Switched Reluctance Motor Controller Design and Implementation

This report provides a comprehensive overview of switched reluctance motor (SRM) controller design. It begins with an introduction to SR motors, highlighting their construction and advantages. The report then delves into the controller design, discussing various control strategies such as voltage PWM and angular position control. It also covers the hardware design, focusing on the power converter, rotor position detection using photoelectric sensors, and phase current detection. The software design section explains the use of DSP C language and modular programming. The document emphasizes the importance of addressing nonlinear properties and challenges in SRM control, aiming to provide a reliable and efficient motor drive system. The report concludes by referencing key components like the TMS320F2812 DSP chip and IGBT modules, offering a detailed insight into the practical implementation of an SRM controller.

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Introduction;
Switched reluctance motor is a brushless AC motor, it is always referred to as SR. This
motor has a very easy mechanical construction and it doesn't need a permanent magnet for it to
work perfectly. It rotor and starter always have main poles. There is no exact number of the
poles on the starter since this will always depend on the number of phases the motor is made to
work on. Usually, one phase of this motor is realized through having two stator poles at opposite
ends. And in this arrangement, a three-phase can be realized by having 6 starter poles. The
number of poles of the rotor is selected not to be the same to the number of poles of the stator
(Gieras, 2014).
SR motor will contain the phase winding only on its stator. Intense windings are always
employed for such motor (Miller, 2014). The windings are put onto the poles of the stator and
then connected in series in order to make one phase of the motor. For a three Phase motor, there
must be 3 pairs of intense windings where each pair of the winding should be connected in series
to make each phase respectively. The mechanical assembly of a 6/4 3-Phase motor is illustrated
in Figure 1 (Hughes, 2011). Other arrangements of such motor are like 4/2 2-Phase SR motor
(having uneven rotor) and 8/6 4-Phase motor is illustrated in Figure 2 and Figure 3 as shown
below.

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Fig 1. Fig 2 Fig 3
Fig 1: Showing the arrangements of 4/2 2-Phase SR motor (having uneven rotor) and 8/6 4-
Phase motor. (Hughes, 2011)
A real structure of the switched reluctance motor for a 4- phase machine having 4 rotor- poles
and 3 rotor pair is shown in the diagram below;
Fig 2: Showing a real structure of the switched reluctance motor for a 4- phase machine having 4
rotor- poles and 3 rotor pair. (Janardnan, 2014)

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The main aim of this project is to come up with a controller for the stepper motor and relate its
design to the controller of the switched reluctance motor (Janardnan, 2014). The micro controller
is then interfaced with the stepper motor as seen in the diagram below;
Fig 3: Showing controller module interfaced with the stepper motor. (Boldea, 2012)
Reflected back from 1980s, the motor drive of a switched reluctance has been considered as one
of the best, reliable and promising speed adjusting driving systems. In both the ac and dc drives
of motors, the SRD has become a good and sufficient competitor as a result of it being simple,
robust, and reliably efficient and possession of high power density. The products that relates to
the switched reluctance motors have been in the late past been applied in various fields and
sectors which includes: electric driving vehicle, appliances used in the household, system of the

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servo, aviation industry and other many more. This has been widely achieved through the
product having much market potential.
It is however difficult creating accurate mathematical models for SRM due to the fact that
magnetic saturation causes many problems relating to nonlinear properties. In addition the SRM
mathematical model inaccuracies are also caused by the effect originating from the eddy together
with hysteresis effects. Nevertheless, the constant change in the strategy of control of the SRM
are always in consideration to the structure and parameters of the SRM thus leading to the
difficulty in achieving a reliable performance of control through the use of a pure traditional
strategy of the PID. This literature therefore discusses the fuzzy PI strategy through a
combination of PID algorithm together with fuzzy algorithm and eventually the 4 phase designs,
the 8/6 pole SRD that is basically grounded on the 32 bit digital signal processor with a general
motive of solving the previously mentioned challenges and problems. The results which are
obtained from the experiment clearly show that certain extents of the challenges and problems
originating from the effects of the nonlinear properties of the SRM can be solved by the scheme.
Strategy of control and structure of the system
The power converter, SRM, detector and the controller are usually the main or major
components of the SRD system. The SRM structure is shown in the below figure 1 of the
literature. Through the control of the motors current of winding switch, the 4-phase, SRM 8/6
pole, power converter energy is transferred. The SRD systems normally have the controller as
the core part or component which is capable of adjusting the current at the phase and the SRM
speed of motor. In addition, its properties greatly and directly have impacts on the SRD system
performance. Rotor position detection and the detection of the winding current forms the general

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components of the detector module. The detector module mainly performs the role of providing
important information of rotor position and the motor winding of the switch state.
Fig. 4 the 4 phase 8/6 pole SRM structure (Athani, 2014)
Maintenance of the SRM speed within the desired parameters is normally the key function or the
obligation of the system of the SRD and the significant point of the system of driving is usually
the torque control. Turn on angle, turn off angle, voltage of the phase and the current of the
phase are the common parameters of control possessed by the system of the SRD. Some of the
strategies for control entails control foe the angular position, chopped current control and finally
the control of voltage pulse width modulation. Angular position control mainly deals with the
speed control and SRM torque through regulation of the turn on angle and turn off angle of the
devices of the main switch while maintaining the input voltage. This strategy is very applicable
and suitable for the high speed, efficient and torque maximum control but extremely not for the
low speed control due to the high peak of current.
Chopped current control is often achieved via control of the switch devices IGBT with an aim
limiting the peak of winding current with an aim of achieving the torque control while
maintaining the turn on angle and turn off angle. Voltage PWM control have a number of
advantages including a possibility of it regulating indirectly the winding current through

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adjustments of the average value of phase windings. In addition, voltage PWM control is
propitious to both high speed and low speed drive systems. Nevertheless, it also possess a faster
dynamic response on disturbances opposing the load which is eventually significant as it aids in
achievement of an effective and reliable SRD operation performance.in consideration to all the
above characteristics or properties, this literature mainly considers voltage PWM as the key
strategy for control.
Design for the system hardware
Diagram below represents the general structure of the hardware with the control chip DSP
TMS320F2812 as a basis. In addition, figure 3 illustrate a picture of TMS320F2812 system of
PCB. TMS320F2812 as a component of the advanced 32 bit DSP chip of a fixed point, has the
capability of reaching 150MIPS as a processing speed. It too have a capability relating to signal
processing and can efficiently achieve very complicated algorithm of control.
In figure 2, the dotted line partially represents the TMS320F2812 inclusive of the all parts of
control of the system which entails the control of current, control of speed and eventually the
control for motor commutation which are fulfilled by DSP software. The power circuit is driven
by the output logic level of the PWM signal originating from the DSP hence controlling the
current and speed of the SRM. Hall current sensors detects the feedback signals which are
delivered to DSP unit of ADC with an intention of implementing the current closed loop control
as the photoelectric sensors detects the feedback signals of the rotor position and is delivered to
the DSP CAP unit with an intention of achieving the speed closed loop control. Nevertheless,
significant information relating to the speed of the motor, current of the winding phase and the
torque output are sent to the display of the LCD through the DSP interface.

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Fig 5. The switched reluctance drive system block diagram (Acarnley, 2013)
Fig 6. TMS320F2812 32 bit digital signal processor photograph (Bartelt, 2013)
The power converter design
In order to improve or enhance the operational reliability, a circuit of half bridge asymmetry is
implanted as the SRD system circuit of power. This enables each phase to be independently
controlled avoiding the phase connections and the idea of the direct connection phenomenon
existing between the arms power circuit bridge. The asymmetry half bridge possesses an
improved utilization of power in comparison to other circuits of power making it more efficient
and reliable. Figure 4 of the diagram clearly represent the asymmetry half bridge topology

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Fig 7. Circuit for power converter (Angila, 2014)
The power switching device 300a/1200v was chosen. It was categorically the switched device
IGBT module SKM300GB123D which is developed by the SEMIKRON Company. It contained
a number of advantages which includes a limited loss in power, an relatively higher speed of
switching and a simple circuit of driving.
The IGBT was driven by the driving module EXB841 which was developed by the FUJI
Corporation. . EXXB841 possess a separated output and input together with it being an
integrated circuit. Nevertheless, EXB841 has a capability performing the over current properties.
The EXB841 is capable of immediately disabling the trigger signals hence avoiding the IGBT
damaging in scenerios that the quantity of current limitation in the IGBT is exceeded.
Detection of the rotor position
There exist 2 rotor position signals functional aspects including:
 Accurate indication of the relative position existing between the rotor and the stator.
 Calculation of the SRM real time speed.
Photoelectric sensors are the position sensors adopted in this literature. Both the two sensors are
installed on the motor shell as illustrated in the figure 5 of the literature with an aim of
generating double square signals of wave possessing 15 mechanical degrees in a period of rotor
angle as the phase difference. 4 distinct positions of reference of the SRM rotor are represented

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by 2 signals in four varying states. Figure 8 of the literature illustrate the position of rotor signals
obtained in the experiment. With an aim of determining the rotor position and the motor speed
after completion of the optical coupling isolation and conditioning of the signal, position signals
are delivered to DSP CAP unit.
Fig 8 : Showing position of rotor signals (Parab, 2012)
a) Stator and rotor relative position
b) Photoelectric sensors P&S relative positions
Fig 9. Detected rotor position signals by the photoelectric sensors (Krishnan, 2013)
Detection of phase current

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Within the system of SRD, phase current detection plays an essential role since it is capable of
providing the winding current information which helpful in achieving the phase current closed
loop control. The current out put sensor mode possess an improved interference resistance
capability when compared to voltage output mode sensor. This is achieved through the high
frequency power switched circuit. In relation to this literature, adoption of LT300-C current
output mode sensor is adopted with an aim of detecting the phase current. Output signals
originating from the hall current sensors are delivered to DSP ADC unit in order to obtain the
SRM value of speed immediately on completion of signal sampling and filtering processes.
Design of the system software
The DSP C language of programming is utilized together with programming method of modular
which utilized during the designing of the software. With an aim of improving the readability
and portability of the programs, subroutines are achieved through compiling of all the shared
programs together with varying functions. The components of the SRD programs of software
entails the main program, AD interrupt program, the initialization system program, the fuzzy
speed control program and the PI current control program.
Control of the motor speed
Control of the SRM speed is managed through the adoption of the fuzzy algorithm due to its
nonlinear variation of parameters suitability. Online adjustments of the PID parameters form one
of the key goals of the fuzzy controller. Analysis of the SRD system should form the basic
grounds for control strategies of the adjustments. Natural language is transformed from the input
variable by the fuzzy controller then secondly to information relating to numerical that contain a
possibility of being identified by the fuzzy controller. In order to blur the achieved results or

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finding, fuzzy reasoning is conducted. The below listed are the most common language
variables:
NB, NS, NM, ZE, PS, PB and lastly PB. These variables are usually selected in the fuzzy
algorithm.
The rule of control of fuzzy controller is generally derived from the operators experience and
relevant experts knowledge. The fuzzy table of control rule takes into reference the common
system features to step response and the input variables relationship. The below diagram is of
fuzzy control table
Fig 10: Showing the diagram of fuzzy control table. (Mangudi, 2013)
Phase current control
The control strategy of the PID is normally adopted in the current closed loop control. The
variables comprised in the linear proportion parameter P, combination are controlled in order to
too control the object. The integral parameter I and the differential parameter D are also
controlled. The below is a description of the discrete PID
In the closed loop control of the SRD, the differential parameter normally overreacts to the
change in the phase current resulting to the system being unstable. This forms the main reason as
to why PI algorithm has been applied in place of PID controlling algorithm.

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Software process
On the commencement of the program, the whole system is immediately initialized. Then on
completion of the digital or analog transformation, in cycles and inquiries are repeated. The
output value is then calculated and modified. At the same time, the LCD will also display the
system information of speed and current. The main flow chart and the A/D interruption and
program is illustrated in the below flow chart.
Fig 11: Showing flow chart and the A/D interruption and program (Bakshi, 2014)
Whereas this flowchart underneath illustrates the current feedback, feedback for the speed and
the initialization of the system.

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Fig 12: Showing feedback for the speed and the initialization of the system (Williams, 2014)
The a- phase current begins to rise rapidly on energization of the a-phase and an important
phenomenon of the chopper is witnessed as the process continues. The value of the current starts
to reduce towards zero steadily on blockage of the a-phase. The brief reflowing time for current
is essential to the motors practical operation although the peak value of the current remains
relatively high affecting the reliability of the switching devices. Nevertheless, the velocity of the
phase current which rises is not sufficiently fast due to the limitation of the maximum PWM
cycle duty. The later experiments will tend to improve all the limitations.
A static torque curve is illustrated in the figure 12 indicating the capability of the machine to
start from any available rotor position. The actual value of measure of torque variation with the
position of rotor under a phase current of 30A is represented by the dotted line while the

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calculated value is represented by the solid line which is calculated through use of an analysis of
ANSYS of infinite element software under a similar condition.
Flow chart in the figure 8 of the main program and interruption of A/D has a calculated value
that is larger in comparison to the actual value of measure since the finite element calculation
adopts the 2-D model while ignoring the motors end effect. The curve of the torque shows that
pole of stator coincides with the rotor pole within 0-8 mechanical degrees of range. However
between 7-9 degrees, the stator pole starts to coincide with the rotor pole. The torque value
rapidly increases beyond 9 degrees and as degree increase, the value of torque output decreases
till 0 at 30 degrees.
With an aim of evaluating the proposed SRM drive system performance, a portion of the results
of the experiments are here shown.
4-phase, 88/6 pole, and 75kw switched reluctance motor shown in fig below are the basis of the
experiment. The drive system range of speed may vary between 1500r/min to 4500 r/min. 336v
forms the rated dc power voltage. The waveforms of the experiment are measured through use of
Tektronix digital storage.
Fig 13: Showing a 4 phases , 8/6 pole switched reluctance motor (Krishnan, 2013)

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STEPPER MOTOR
This type of motor also does not contain any brush just like the switched reluctance .It is
an electromechanical machine that changes electric pulses supplied at their windings in the
excitation to exactly definite step-by-step rotation of the shaft of the motor (Boldea, 2012). This
shaft always rotates at an immobile angle for every discrete pulse. The rotation in most cases is
angular or linear. If the pulses are supplied to it, it will be turned through a given angle (Dubey,
2013). This angle is known as the step angle, it is usually given in degrees. The number of pulses
at the input of the motor will determine the step angle thus determining the locus of the shaft of
the motor will be highly managed through controlling the number of pulses of the motor
(Krishnan, 2013). This distinctive nature of the motor makes it be highly appropriate for open-
loop control system where the exact location of the shaft is kept with a particular amount of
pulses minus employing a sensor at the feedback (Mohan, 2014).
Then a number of steps per revolution will be higher for a less step angle and more will be the
precision of the location obtained (Krishnan, 2017). The step angles in some case are up to 900
and can go as low as 0.720, nonetheless, the usually employed step angles are as follows 1.80,
2.50, 7.50 and 150. The direction of rotation of the shaft is subject to on the arrangement of pulses
supplied to the stator (Emadi, 2014). The usual motor speed or speediness of the shaft is always
proportionate to the input pulses frequency that is supplied at excitation windings (Rashid,
2012). Hence, with a low frequency, this motor will revolve in steps and when in high frequency,
the motor will continuously revolve like a DC motor this is because of the force of inertia
(Sheets, 2012).

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As for all electric motors, stepper motor contains a stator and a rotor. The rotor is always the
mobile part and it has no brushes, a commutator and windings. Usually, the rotors are either
mutable reluctance type or a permanent magnet (Gieras, 2011). The stator is always built with
multiphase and multi pole windings, generally of four phase or three windings wound for an
essential number of poles defined by anticipated angular displacement for every input pulse.
Contrasting other types of motors, it works on a programmed logics distinct control pulse which
is supplied to the windings at the stator through an electronic drive (Athani, 2013). The
revolution transpires as results of the interaction of the magnets between the poles of the rotor
and poles of the successively energized stator winding. And because this motor always works in
a programmable way it basically used with the controller modules like 8086 microprocessor.
And such motors can be illustrated by the diagram below;
Fig 14: Showing the connection of stepper motor. (Athani, 2013).
CONSTRUCTION OF A STEPPER MOTOR

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For the construction of this kind of motor, it entails a wound stator and soft iron multi-tooth
rotor. The stator contains a heap of silicon steel laminations where windings at the stator are
always wound. Ordinarily, the wound is done in three phases that are dispersed amid the pole
pairs (Acarnley, 2013). The number of poles on stator hence made is equivalent to an even
several the number of phases where windings are made on the stator. In the diagram below, the
stator contains 12 evenly spaced protrusive poles for which every pole is wound with an exciting
coil (Russell, 2010).
The rotor contains no windings hence it is of salient pole kind formed exclusively of laminations
of slotted steel (Bakshi, 2014). The pole of the rotor protruded teeth contain equal width like that
of the teeth of the stator. The amount of poles available on stator varies to the poles of the rotor
that give the capability to rotation of the motor which is bidirectional and self-start (Husain,
2013). The below is the relationship of rotor poles as far as poles of the stator for a 3 phase
motor is concerned;
Nr = Ns ± (Ns / q).
Here q= 3, Ns = 12 therefore
Nr = 12 ± (12 / 3) = 16 or 8.
The diagrams below show parts of the stepper motor that are employed in its construction.

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Fig 15: showing parts of the stepper motor that are employed in its construction. (Sugawara,
2014)
But there are several types of the stepper motor hence the construction may slightly differ from
one type of the motor to another (Sugawara, 2014). The given process of construction above is
basically the general one which is almost employed for the all types of the stepper motors used in
the building of the magnetic circuit there are three kinds of motors (King, 2012):
 Hybrid.
 Permanent magnet ( this is an active type)
 Variable reluctance (this is a reactive type)
Variable reluctance (VR) stepper motors:

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This motor contains evenly dispersed teeth which are of iron, on both the rotor and the stator,
control windings that are attached to the teeth of stator whereas the rotor is treated to be passive
(Bakshi, 2014). Through activating one phase or many, the rotor will hence rotate in such a way
that the field lines of the magnetic must follow the least path of the reluctance, for instance, the
teeth rotor should bring into line either with the bisectrix of the electromagnetic poles of stator or
teeth on the stator,
For this type of construction, it will permit realizing small to medium step angles and function at
high frequencies which are highly controlled (Irwin, 2014). Nonetheless, this type of motor can’t
hold its location, for example, it lacks holding torque if no current passes via the windings in the
stator (Scarpino, 2015).
The movement of the current via the VR motor windings must not be inverted to achieve
reversion the rotation direction, this is realized by the impulse arrangement. Hence this kind of
control, where the movement of current must not be inverted is known as unipolar (Hughes,
2014).
Permanent magnet (PM) stepper motors:
This type of stepper motor has a several constructions, for the PM the rotor’s teeth are
permanent magnet having poles put in a radial orientation, but the stator construction is the same
(Liptak, 2015). If the stator windings are energized, magnetic fields which are produced due to
the interacting with the PM’s flux, producing torque to help the rotor to rotate (Miller, 2015).
Control arrangements for this are the same to VR motors nevertheless when for example the
south pole of a PM reaches an electromagnetic south pole on the stator, the current moving via

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the respective winding should be inverted, so as to produce an electromagnetic north pole to help
maintain the direction of the forces (Melkote, 2013). Therefore, the phases are energized through
charging the polarity impulses, hence this kind of stepper motor is known as bipolar. In this
motor, a higher torque is provided and it also has the ability to hold torque, if the windings are
not energized (Hu, 2014). Steps will be large, for example from 450 to 1200, since the number of
permanent magnets that can be attached on the rotor is lesser than the number of teeth on the VR
motor’s stator (Angila, 2014).
Hybrid stepper motors:
Hybrid stepper motor always combines the above discussed two types of motors. Therefore in
its construction in combines the construction techniques for the above two (John, 2014). In this
motor, the rotor is constructed from a permanent magnet, having two toothed crowns
Ferromagnet, and it is mounted on both poles of the magnet, this will hence make the teeth of
one crown to be north poles and the other crown south poles (Angila, 2014).
The diagram below illustrates the basics behind the connection of the stepper motor

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Fig 16: Showing overall connection to the stepper motor (Angila, 2014).
PRINCIPLE OF OPERATION
As it is known for all motors that they convert electrical energy to motion (mechanical energy).
The same is for the stepper motor but with it, it converts the electrical energy to mechanical
energy in (motion/ rotation in a specific direction). The movement produced by every pulse is
exact and repeatable, and for that matter, stepper motors are very actual for location applications
(Clade, 2014).
PM stepper motors integrate coil windings, magnetically conductive stators and
permanent magnet rotor. Energizing winding of a coil makes an electromagnetic field having a
South and the North Pole. The stator conveys the magnetic field. It is highly possible to alter

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magnetic field through successively energizing the stator coils that produce rotary movement.
This can be illustrated by the help of figure 17 below for the two-phase motor,
For the first Step phase, A of a two-phase stator will get (activated) energized. This will
magnetically lock the rotor in the location indicated, this is due to the fact that unlike poles will
attract if phase A is turned off while phase B is turned on, the rotating of the rotor will be in
clockwise 90°. In the third step, phase B is turned on having the inverted polarity from Step 1,
this will make another rotation of 90°. For Step 4, phase B turned on and phase A will be turned
off, having polarity inverted from Step2. Doing this step again will make the rotor to have
another rotation in 90° steps in the clockwise direction. This stepping arrangement is shown in
figure 1 is known as "one-phase on" stepping. An elaborate communal technique of stepping is
"two-phase-on" in this case the two phases of the motor will get energized.
Nevertheless, it is only the polarity of a single phase is turned on at a given time.
The stepper motor can as well be "half stepped" through introducing an off state amid
transitioning phases. This will cut a complete step angle in half of the stepper. For instance, a 90°
stepping motor would rotate 450 on each half step. Nevertheless, half stepping classically leads to
a 20% to about 30% loss of torque but this will depend upon step rate if equated to the two-
phase-on stepping arrangement. Because one of the windings is not activated when every
alternating half step there is the fewer force of electromagnetic applied to the rotor leading to a
loss in torque. These are further illustrated by the following diagrams

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Fig 17: Showing diagram for the principle of operation of a stepper motor. (Angila, 2014).
Using the following prototype diagram of the stepper motor as a reference point
Fig 18: Showing a principle diagram of stepper motor operation. (Angila, 2014).

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For the PM kind of stepper motor, a PM is employed for coils and rotor are put to the
stator. The motor prototype that contains 4-poles as illustrated in figure 9 below. For this
arrangement, the rotor step angle is 900. Coil X, coil x̅ and coil Y, coil Ȳ coil coincides
respectively. For instance, coil Y and coil Ȳ should be the upper pole and below pole
respectively. Coil Y and coil Ȳ are rolled up for the path of the pole which should be reversed if
an electric current to the coil Y is used and then using an electric current to the coil Ȳ. This is
similar to X and also x̅ .
For the clockwise operation of this stepper motor, its analysis will appear as below
Fig 19: Showing the stepper motor clockwise motion in step 1. (Angila, 2014).

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Fig 20: Showing the stepper motor clockwise motion in step 2. (Angila, 2014).
Fig 21: Showing the stepper motor clockwise motion in step 3. (Angila, 2014).
Fig 22: Showing the stepper motor clockwise motion in step 4. (Angila, 2014).

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The below table 1 summarizes the inputs for the stepper motor operating in a clockwise direction
for all the four possible steps.
Motion Steps X x̅ Y Ȳ Hex Values Angle
Clockwise
1 0 1 0 1 5H 00
2 1 0 0 1 9H 900
3 1 0 1 0 AH 1800
4 0 1 1 0 06H 2700
Table 1: Showing the summary the inputs for the stepper motor operating in a clockwise
direction for all the four possible steps.
The Movement of the stepper motor in table 1 above, it is highly possible to obtain the angle for
each of the steps as seen in table 2 below;
For the anticlockwise operation of this stepper motor, its analysis will appear as below
Fig 23: Showing the stepper motor anticlockwise motion in step 1. (Angila, 2014).

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Fig 24: Showing the stepper motor anticlockwise motion in step 2. (Angila, 2014).
Fig 25: Showing the stepper motor anticlockwise motion in step 3. (Angila, 2014).

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Fig 26: Showing the stepper motor anticlockwise motion in step 4. (Angila, 2014).
The below table 2 summarizes the inputs for the stepper motor operating in anticlockwise
direction for all the four possible steps.
Motion Steps X x̅ Y Ȳ Hex Values Angle
Anticlockwis
e
1 0 1 0 1 5H 00
2 0 1 1 0 6H -900
3 1 0 1 0 AH -1800
4 1 0 0 1 9H -2700
Table 2: Showing the summary the inputs for the stepper motor operating in anticlockwise
direction for all the four possible steps.
It is possible to see the figure that the rotor is steady in the center of 2 poles of the stator. But if
one side of the polarity of the stator is altered, the bound by the magnetism will transpire. This
will lead to the direction of rotor's turn being fixed.
The nature of this motor is that it is possible to manage the angle appropriately and to be in a

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steady rotation. Furthermore, because of the fixation of the rotor by the magnetism in the still
circumstance as illustrated in the principle pics above, the static power is enormous.
The case of the clockwise control is illustrated in the table below. The arrangement of X, x̅, Y
and Ȳ echoes the four patterns as below.
X x̅ Y Ȳ Step angle
0 1 0 1 0.0°
1 0 0 1 7.5°
1 0 1 0 15.0°
0 1 1 0 22.5°
0 1 0 1 30.0°
1 0 0 1 37.5°
1 0 1 0 45.0°
0 1 1 0 52.5°
0 1 0 1 60.0°
1 0 0 1 67.5°
1 0 1 0 75.0°
0 1 1 0 82.5°
0 1 0 1 90.0°
1 0 0 1 97.5°
1 0 1 0 105.0°
X x̅ Y Ȳ Step angle
0 1 0 1 180.0°
1 0 0 1 187.5°
1 0 1 0 195.0°
0 1 1 0 202.5°
0 1 0 1 210.0°
1 0 0 1 217.5°
1 0 1 0 225.0°
0 1 1 0 232.5°
0 1 0 1 240.0°
1 0 0 1 247.5°
1 0 1 0 255.0°
0 1 1 0 262.5°
0 1 0 1 270.0°
1 0 0 1 277.5°
1 0 1 0 285.0°

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0 1 1 0 112.5°
0 1 0 1 120.0°
1 0 0 1 127.5°
1 0 1 0 135.0°
0 1 1 0 142.5°
0 1 0 1 150.0°
1 0 0 1 157.5°
1 0 1 0 165.0°
0 1 1 0 172.5°
0 1 1 0 292.5°
0 1 0 1 300.0°
1 0 0 1 307.5°
1 0 1 0 315.0°
0 1 1 0 322.5°
0 1 0 1 330.0°
1 0 0 1 337.5°
1 0 1 0 345.0°
0 1 1 0 352.5°
With the switched reluctance motor operation, the machine torque production is illustrated
through utilization and the aid of the electromechanical energy production principle applied in
the machine coil. The phase windings inductance of a particular machine differs in relation to the
inductance values in comparison to the angle of the rotor during rotation of the rotor. As a result
of the variable reluctance motor possessing the nonlinear motor behavior, the current level and
the rotor position are major factors that have impacts on the phase inductance.in addition, there is
too speed dependent vback emf that usually large below and above the average common speed
that forms the underlying drive behavior. Despite the machine containing structures that are
simple, its electromagnetic mode of conduct is usually convivial. The below is an illustration of
an expression of the energy for the electrical input:
Nevertheless, the back emf and the switched reluctance motor model linear inductance are
usually directly proportional to the speed of machine which normally significantly aids in finding

Electrical Engineering 32
out the behavior of the drive type or nature. The below are diagrams and characteristics or
features of the solenoid coil:
The back emf is usually ignored in an operation mode with a low speed in a manner that it can be
placed in a comparison with the voltage of a dc bus. The machine can be further concluded or
assumed to be a machine for current fed driving. This mode of operation of current fed is usually
achieved through the technique for regulation of current pulse width modulation. The current of
the phase is normally to be designed with an aim of making it close to a square form of wave
which is aimed at minimizing pulsations for the torque in company to proper converter and
converter. In a medium speed range machine, the back emf usually increases. During designing
of the waveform, the phase is occasionally excited with an aim of compensating the loss. At this
state, the speed of the machine runs at acceleration below and above the base speed.
The phase windings are further fed with the voltage during this mode of operation leading to the
technique being called the pulse dropping mode. This type of designing system for drives must at
all times be kept to maintain the design capability for the pulses of the current generally for
maintaining accurately the variable reluctance motor values even at any suitable power
converter or controller.

Electrical Engineering 33
Fig 28 : Showing ross sectional model of a three phase VR motor, winding arrangement, and
equilibrium position with phase 1 excited (Bakshi, 2014)
The conduction angle for the phase current is controlled and synchronized with the rotor
position, typically through a way of a sensor shaft position. Since the movement of the rotor, and
thus the
generation of power and torque, contains a switching of currents to stator windings when there
is a variation of reluctance, this variable speed SR motor is referred to as a switched reluctance
motor (SRM)
TORQUE OF THE STEPPER MOTOR
Torque is the amount of rotational force which is generated by a motor as it runs. In a particular
use, the torque for every axis is determined through a precise necessity in the machine, this is
needed to make the object being driven by the motor. The torque necessity of the axis defines
the motor size and any lubrication (gearing) required.
Several engineers like those at Portescap aim at improving the output torque of the motor during
its design. The chief constituents employed in the production of torque of this motor are the
winding, flux path and the magnet. The energy of the magnet helps in the driving of the motor
but the balancing in the motor should be realized between the cost and power. Similarly, the
amount of torque will be higher when the number of the pole in the magnet is also higher for the
same power dissipated. The stepper motors having high torque are examples of this because they
contain many pole pairs for a specified size motor. Portescap engineers improved the design of

Electrical Engineering 34
the motor based on the motor’s energy content, physical size, the geometry of the magnet and the
pole pair count.
The content of the copper winding adds to the power supplied by the motor. Striking the right
balance is significant for producing high torque stepper motors which can optimize torque but
drawing relatively less amount of power. Flux path controls all of the fields in the magnet for the
functional channel and reducing losses. A high torque stepper motor which is capable of
producing high power but contains high losses which will not hence benefit the application of
this type of motor. Fathoming the full design of the motor enables Portescap engineers to make
the most power possible into the smallest package of the motor.
Portescap came up with the Athlonix DC motor having no core to help maximize output torque
of the motor whilst maintaining minimal length and minimal length. High-energy neodymium
magnets are employed to offer the foundation for the torque density of this stepper motor. High-
capacity windings of the motor will help to increase electromagnetic intensity and current
density with slight joule heating. The advanced air gap design needs less power to realize the
high torque output, permitting the motor to function at a high efficiency. An extra method to
optimize torque output is through using gearheads which help in reducing the friction operation.
The DC gear motors offer a higher output torque by the gearbox containing the supplementary
decrease in output speed. And such design of stepper motor is shown in the figure below;

Electrical Engineering 35
Fig 29: Showing a stepper motor designed to maintain the higher torque but to reduce losses.
(Bakshi, 2014)
For the stepper motor or any other type of motor, there is a relationship between the speed and
the torque. It is highly necessary to be familiar with how to interpret a torque-speed graph since
it defines what a stepper motor is capable of doing and what it cannot do (Bakshi, 2014). It is as
well worth noting that a torque-speed graph is for a particular driver and particular motor.
Torque is will fully depend on the voltage and driver type. A single motor may contain diverse
torque-speed curve if employed with a diverse driver. The torque-speed graphs for this catalogue
are only for reference. A given motor with the same drive, same voltage, and same current must
give the same operation (Bartelt, 2013). Torque-speed graphs may as well be employed to
approximately approximate the torque generated using diverse drivers at changing currents and
voltages.

Electrical Engineering 36
Holding Torque
Holding torque is the quantity of torque which the motor generates if it contain rated current
moving via the windings of the stepper motor when the motor is at rest.
Detent Torque
Detent Torque quantity of torque which the motor generates when it is not yet energized.
Therefore for this torque, there is no current is moving via the motor windings.
Pull-in Torque graph
Pull-in Torque graph indicates the highest quantity of torque at particular speeds which the motor
is able of starting operation, stopping operation or even retrogressing in synchronism having the
input pulses. The motor can’t commence its operation at any speed that is above this curve. It
can’t suddenly stop or reverse with any precision at a point above this curve.
Stop / Start Region
Stop / Start Section is an area below and on the pull-in curve. For every value of load in this
location, the motor can stop, start, or even inverse “suddenly” (there is no ramping needed) at the
conforming the value of speed.
Pull-out Torque Curve

Electrical Engineering 37
Pull-out Torque graph indicates the optimum torque value at particular speeds where the motor is
able of producing torque as it operates synchronism. When the motor is operating beyond of this
graph curve, it will definitely stall.
Slew Range
Slew Range is the area amid the pull-out curves and the pull-in, where to keep synchronism, and
the speed of the motor should be ramped (Ltd, 2015).
The below graph illustrates the above definitions
Fig 30: Showing the definition of terms in a torque-speed graph. (Ltd, 2015)
The diagram below fully illustrates the relationship between the speed and the torque for
the stepper motor.

Electrical Engineering 38
Fig 31: Showing the relationship between the speed and the torque in a stepper motor.
(Ltd, 2015)
And in the above diagram of the speed- torque, it is vividly shown that torque is inversely
proportionate to the motor speed. When the motor speed is higher the torque is lower and when
the torque is higher the speed is lower.
The time is related to the inductor and the resistor of the motor as shown in the below equation.
t = L
R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Where L is Inductance in mH , R is resistance in Ω and t is electrical time constant in ms.
In summary, the quantity of coil turns in the windings and the current defines the optimum
torque output a motor, whereas the voltage supplied to the stepper motor as well as the windings
of the inductor will influence the speed at which a particular amount of torque can be produced.

Electrical Engineering 39
generation in SRM is explained through the fundamental standard of electro-mechanical energy
transformation.
The incremental mechanical energy in terms of the electromagnetic torque and variation in
position of the rotor:
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The electromagnetic torque is given by the following equation
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The torque physical characteristics of SRM are reliant on the relationship amid flux linkages and
position of rotor as a function of current.
• For rectangular currents, it can be viewed that the motoring torque is generated for a short
duration in pulsed form, causing in a big torque ripple.
• The following two ways can be used to minimize the ripples torque:
- Shape the phase current
- Optimal design of inductance profile

Electrical Engineering 40
Electrical equation is given by the below equation
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The electrical equivalent circuit is given below,
Fig 32: Showing electrical equivalent circuit
The SRM drive system is shown in the diagram below

Electrical Engineering 41
Fig 33: Showing SRM drive system is shown in the diagram below
The following diagram illustrates the sensors used in the switched reluctance motor
Fig: 34 Showing the Phototransistor position sensor
EFFICIENCY OF THE STEPPER MOTOR
The efficiency of the electrical motor can be obtained using the below two equation;
The first equation is the efficiency when the shaft power is in terms of watts
1. Ƞm = Pout
Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Where Ƞm = efficiency of the motor, Pin is the input power of the motor, Pout is the output power
of the motor
The second equation is the efficiency when the shaft power is in terms of watts in Horsepower

Electrical Engineering 42
2. Ƞm = 746 Pout
Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The electrical power lost in the secondary and motor stator winding resistance is known as
copper losses. It can be expressed as below
Pcl = R I2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
LOAD ANGLE OF STEPPER MOTOR
Stepper motors are perfectly made for positioning tasks for open-loop at a relatively low
power consumption. The position of the rotor of the motor can easily be controlled by the
operator of the motor. Each time a next pulse is sent by the operator, the stepper motor driver
excites the accurate phases of the stator to rotate the rotor over an already defined distinct
angular position. For that matter, counting the command pulses step permits open-loop locating
of the stepper motor (Maas, 2012). Nonetheless, if the motor is stuck or overloaded, the
relationship between the anticipated position of the rotor based on the number of step command
pulses and the real position of the rotor is completely lost. This is known as step loss. Open-loop
stepper motor techniques do not notice this step loss. Whereas the total position of the rotor is
lost, the control of open-loop continues to send needless and undesirable step command pulses.
This will then results in excessive vibrations, wear and eventually noise during the operation of
the stepper motor. Particularly for vigorously demanding applications of the stepper motor, step
loss must be evaded or at least be detected and then reduced (Alciatore, 2013). Using a sensor for
mechanical position to realize closed loop control would make the cost of this motor high and
make it more complex of the system and omits the forthright open loop control. Hence in this
research article, a sensorless estimator pegged on a Phase Locked Loop is availed that gives a

Electrical Engineering 43
feedback of the even during transients and load angle. The load angle has info on the generation
of the torque and the margin to step loss. To approximate the load angle, the back-EMF is always
taken into account (Parab, 2012). This algorithm is always employed with the typical half-, full -
and micro-stepping algorithm and it only requires one voltage and one current measurement and
electrical parameters like inductance and resistance to approximate the back-EMF of the stepper
motor and afterwards estimate the load angle. Graphically the load angle of the stepper motor
can be illustrated as below
Fig: 36: Showing the load angle of the stepper motor graphically. (Parab, 2012

Electrical Engineering 44
TYPES OF STEPPER MOTORS
Variable Reluctance
Variable Reluctance is a type of motor which doesn’t need a permanent magnet in its operation.
Therefore the rotor can run without ‘detent’ or constraint torque.
This type of motor is not common and is usually employed in applications which do not need a
high degree of torque, like the location of a micro slide.
Permanent Magnet
This type of motor is also known as to as a tin can or can stack motor, its rotor is built using a
permanent magnet. It has a relatively low speed and relative a low torque, and it has large step
angles which are either 45 or 90 degrees. The simple building allows these motors to be
manufactured at low cost, this will hence make them the idyllic choice for low power uses.
Hybrid Stepper
This version of a Stepper Motor is a clever combination of the variable reluctance and
permanent-magnet types.
APPLICATIONS OF A STEPPER MOTOR
1. Industrial Machines – Stepper motors are always employed in machine tooling
automated manufacturing equipment and automotive gauges. In most industrial
machines, motions like rotations are always required hence such motors are always used.

Electrical Engineering 45
2. Security – Stepper motors are used in new surveillance products for the security industry,
this will enable a keen and accurate surveillance.
3. Medical – Stepper motors are employed in medical machines like samplers, scanners,
and as well used in fluid pumps, digital dental photography, and blood analysis and
machinery of respirators.
4. Consumer Electronics – Stepper motors are also employed in cameras for programmed
digital camera emphasis and zoom functions of the camera.
BENEFITS OF STEPPER MOTOR:
1. The angle of rotation of the motor is proportionate to the pulse input.
2. Accurate repeatability and positioning of motion because decent stepper motors operate
at a precision of 3 – 5 %.
3. Exceptional response to starting, stopping and even reversing.
4. The response of the motors to digital input pulses gives an open-loop control. This makes
the motor less costly and simpler to control.
5. It is highly consistent because there is no brush contact in the motor. Hence the life of the
motor is simply reliant on on the life of the motor’s bearing.
6. An extensive range of revolusion speeds can be realized as the speed is proportionate to
the frequency of the input pulses.
7. The motor operates at a full torque at standstill.
DRAWBACK OF STEPPER MOTOR
 The motor operates at a relatively low speed

Electrical Engineering 46
 The motor has a low power efficiency
 It has a low torque
 The motor has a fixed step value
Driving a Stepper of a stepper
Driving a stepper motor is somehow more complex than driving a normal brushed DC motor.
Stepper motors need a stepper controller to energize the phases in a sequence which is timely to
cause the rotation of the motor. The stepper controllers which help in the driving of such a motor
is shown in the diagram below;
Fig 37: Showing the driver controllers of a stepper motor. (Marston, 2014)
Simple Unipolar Driver

Electrical Engineering 47
As the name suggests this is the simplest type of driver which is being built with a bit of
transistor. These transistors are simply switched off and on in sequence to energize the step the
motor and phases. Unipolar drivers are comparatively cheap to develop but only operate with
unipolar motors. The diagram below illustrates the stepper motors connected with the control
driver module;
Fig 38: Showing the stepper motors connected with the driver control unit. (Krishnan, 2017)
With either the configuration of the motor, the motor will always manage a single step every
time there is a change in polarity of the current stator winding. For a motor having a single pole
pair on the rotor which relates to 4 steps per electrical cycle. Figure 24 illustrates the step
arrangement and ideal current waveform for a two-phase bipolar stepper motor. For Figure 24,

Electrical Engineering 48
every time the current in one winding is inverted, this makes the motor to makes just a step of
90°. Certainly, no stepper motors would use such a course step. Usual stepper motors are 7.5° or
1.8° per step conforming to 48 or 200 steps for every rotation. A 200 step per rotation motor
contain 50 pole pairs on the rotor and require 50 electrical cycles for every mechanical rotation
of the motor.
Fig 39: Showing half-step sequence for a two-phase bipolar motor. (Williams, 2014)
Figure 23 above illustrates the arrangement for half-step drive and the ideal current waveform
for a two-phase bipolar stepper motor. For a half-step, we will have about 8 half-steps for every
electrical sequence and the operational resolution of the motor will be doubled.

Electrical Engineering 49
Fig 40: Showing Full-step sequence for a two-phase bipolar motor. (Parab, 2012
The key benefit of half-step is the improved resolution. And the key drawback of half-step
working is such a way that in the half-step state the motor will contain just about 70 percent of
the torque as when operated to the full-step state. And that is the direct outcome of lower flux
density in the stator.
For the full-step state, the vector of magnetic produced by the stator is the total amount of the
vectors of magnetic of the two coils. If both coils are agitated equally, the vector sum of the two
is obtained to be at a 45° angle and contain a size of √2 times that size of every individual vector.
If only a coil is driven, as in the half-step states, the sum of magnetic vector is just the vector for
one coil. This is about 30% decrease in torque for the half-steps. The decrease in torque is
always compensated for through cumulative the current in the one coil being driven for the half-
steps. When the current is increased by √ 2 if only a coil is driven, as illustrated in
Figure 25 below. The torque is fundamentally alike for the half-step and full-step and states.

Electrical Engineering 50
Fig 41: Showing the arrangement for half-step drive and the ideal current waveform for a two-
phase bipolar stepper motor. (Parab, 2012)
Controlling stepper motors is better explained through using some of the below types of motors
we can easily get to fully understand the controlling techniques. This can be well illustrated
through the below two types of the stepper motor.

Electrical Engineering 51
Fig 42: Showing the bipolar motor. (Parab, 2012)
This type of motor contains two coils and four wires. To ensure it operate, one needs to supply
current via the coils. Every wire should be able to be driven low and high. The diagram below
illustrates how to drive the current to make the stepper motor rotate.
Fig 43: Showing the different positions of working motor. (Parab, 2012)
Fig 50: Showing the different positions of working motor. (Mangudi, 2013)
Obviously, utmost stepper motors contain more than 4 steps. The typical stepper motor will
always contain 200 steps for every rotation (Kridner, 2014). Rotation of the motor this way is
known as full-stepping (Athani, 2014). Half-stepping is very simple when one has a full-

Electrical Engineering 52
stepping operation (Mangudi, 2013). One can send current via the two coils simultaneously, and
this will definitely double the resolution (Rhama, 2014).
Fig 51: Showing the connection of the motor with the circuit diagram for the driver. (Kridner,
2014).
How stepper motor is related to a switched reluctance motor
Unlike other ordinary motors which contain the brush in their operation, both the stepper motors
and switched reluctance motors are brushless, they always operate perfectly without any brush
(Scarpino, 2014).
Controller design for stepper motor using transistor, diode and timer circuit
Components required for the design
 555 Timer IC
 4 x 1 KΩ Resistors (1/4 Watt)

Electrical Engineering 53
 CD4017 Johnson Decade Counter
 4 x 1N4007 PN Junction Diodes
 470 Ω Resistor (1/4 Watt)
 100 KΩ Potentiometer (Knob type)
 4 x 2N2222 NPN Transistors
 2.2 KΩ Resistor (1/4 Watt)
 100 pF Ceramic Disc Capacitor
 1μF 16V Polarized Capacitor
 12V Power supply
 Connecting Wires
 Breadboard (Prototyping Board)
 12V Stepper Motor (Unipolar – 5 Wire)
 The below is the circuit diagram of the stepper motor speed control circuit diagram

Electrical Engineering 54
Fig 52: Showing the circuit diagram for the stepper motor speed control circuit diagram.
(Hughes, 2011)
Circuit Design
The design will be begun by the Square wave Generator for instance 555 IC in Astable Mode. A
resistor value of about say 2.2 KΩ is coupled between the Discharge Pin and VCC of 555. A
100 kΩ is then employed by connecting it between the Threshold pin (Pin 6), and Discharge Pin
(Pin 7) that is in turn shorted with the Initiated Pin (Pin 2) (Hu, 2014).
A Capacitor of 1 μF is wired amid the GND and the Trigger pin (Pin 2). A capacitor of 100 pF
which is a Bypass is wired to the Control Voltage Pin which is at Pin 5. The other pins like Pin 8
(VCC) is wired to a supply12V Reset Pin (which is Pin 4) to a supply 12V and Ground Pin
(which Pin 1) to GND (Maas, 2012).

Electrical Engineering 55
The Output of this Timer IC which is at the Pin 3 is treated as Input Clock to the Counter IC
CD4017 (to its 14th Pin) (Naibu, 2011). The VSS and VDD pins of CD4017 that is Pin 8 and 16
are connected to GND and 12V Supply in that order (Marston, 2014). This Permits Pin 13 to be
connected to ground (Service, 2015).
The control of the 4 coil termini of two coils in the stepper motor is then required. Therefore, we
require just 4 outputs from the stepper motor driver (Williams, 2014). The outputs of the stepper
motor are Q 0 to Q3 that is Pins 3, 2, 4 and 7 respectively (Alciatore, 2013). The outputs of the
IC are then wired to the base terminals of 4 transistors via a different 1 KΩ Resistors (Hollings,
2013).
The counter should then be reset on the 5th pulse and therefore the Q4 (which is at Pin 10) that is
nothing but the 5th output is wired to help in resetting the pin of CD4017 that is pin 15 and this
pin is wired to GND via a 470 Ω Resistor (Bartelt, 2013).
Timing response for a stepper motor
The timing response for the stepper motor is best explained using the below graph. (McComb,
2012);

Electrical Engineering 56
Fig 53: Showing the timing response for the stepper motor. (Acarnley, 2013).
When the motor starts as it oscillates through the step angle, the oscillation occurs until the
motor is fully settled. And the time it takes to settle is known as the settling time (Acarnley,
2013).
Protocol to design the controller for a stepper motor
Stepper Motor Controller SNAP Protocol Version 0
This protocol communicates by the help of the SNAP communication protocol and admits
several commands to help in controlling a single stepper controller and also doing the
coordinated motion with several stepper motors (Fluck, 2014). The below are some of the
command protocol for the stepper motor controller (Edwards, 2014).
[1] Set forward motion
This will help to start the motor turning indeterminately in a forward direction. If the motor
attains the optimum position sensor then the movement will definitely stop (Margolis, 2014).
Its parameters include
 Speed to turn (0 to 255)
 one byte
And its Returns is
 Nil.

Electrical Engineering 57
[2] Set reverse movement
This protocol begins the motor and turns it indeterminately in an opposite direction (Perrin,
2015). If the motor attains the minimum position sensor motion will hence stop (Hamzah, 2015).
It's Parameters:
 Speed to turn (0 to 255)
 one byte
And its Returns is
 Nil.
[3] Set counter position
Parameters:
 One byte: lower order byte of the 16-bit counter position
 one byte: higher order byte of the 16-bit counter position
Returns:
 Nil
[4] Get position counter
Parameters:

Electrical Engineering 58
 Nil
Returns:
 One byte: lower order byte of the 16-bit counter position
 one byte: higher order byte of the 16-bit counter position
[5] Seek to position
Parameters:
 One byte: Speed to move
 One byte: lower order byte of the 16-bit counter position
 One byte: higher order byte of the 16-bit counter position
[6] Power down motor (torque off)
For this protocol, it will Powers the stepper motor down hence it will turn freely (Ltd, 2015).
This is achieved by dropping the enable line and the outputs for four-stepper (Owings, 2013).
Parameters:
 Nil
Returns:
 Nil
[7] Enable asynchronous notifications

Electrical Engineering 59
This protocols communicate to and informs the stepper board to alert the host when it has
attained the target for its mode (Sugawara, 2016).
Parameters:
 One byte: address to notify
Returns:
 Nil
[8] Prepare for synchronized movement
Parameters:
 One byte: a synchronized mode for the stepper motor, this is based on the table below:
Returns:
 Nothing
Value Meaning
0 No synchronization
1 synchronized seeking
2 Incremental synchronization. Move motor forward 1 step every synchronized pulse
3 Decremental synchronization. move motor backwards 1 step every synchronized pulse

Electrical Engineering 60
[9] Calibrate
This protocol helps to initiate the routine of calibration (Parab, 2012). This contains seeking a
home sensor that is setting the position to zero hence looking for maximum sensor position and
recording it. (Chhabra, 2014)
Parameters:
 One byte: Speed to move ( from1 to 255)
Returns:
 Nil
Returns:
 Nil
I/O pulses for the stepper motor.
Steps Axis Movem
ent
mode
Speed Positio
n
Acceleratio
n
Deceleratio
n
Positionin
g/
Pushing
Area
1
Area
2
In position
mm/s mm mm/s2 mm/s2 mm Mm mm
Axis1 ABS 100 200 1000 1000 0 6 12 0.5
Axis 2 ABS 50 100 1000 1000 0 6 12 0.5
Axis 3 ABS 50 100 1000 1000 0 6 12 0.5
Axis 4 ABS 50 100 1000 1000 0 6 12 0.5

Electrical Engineering 61
1
Axis 1 INC 500 800 1000 1000 1 0 0 0.5
Axis 2 INC 500 900 1000 1000 1 0 0 0.5
Axis 3 INC 500 900 1000 1000 1 0 0 0.5
Axis 4 INC 500 900 1000 1000 1 0 0 0.5
2046 Axis 4 ABS 200 700 500 3000 0 0 0 0.5
2047
Axis 1 ABS 500 0 3000 3000 0 0 0 0.5
Axis 2 ABS 500 0 3000 3000 0 0 0 0.5
Axis 3 ABS 500 0 3000 3000 0 0 0 0.5
Axis 4 ABS 500 0 3000 3000 0 0 0 0.5
Practical Simulation results for the stepper motor
When the simulation for the stepper motor is done using the Simulink software the following are
the results (Kirk, 2015).

Electrical Engineering 62
Fig: Showing the output signal from a signal building block of the stepper motor driver control.
Fig 54: Showing a hybrid stepper motor transient performance characteristic at no load.
From circuit breaker simulation, the following are the waveform obtained (Engineers, 2012).

Electrical Engineering 63
Fig 54: Showing the output signal from a signal building block of the stepper motor driver
control.
Fig 55: Showing a Microstepping Current Waveforms.

Electrical Engineering 64
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Electrical Engineering 65
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Electrical Engineering 66
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