AC/DC Circuit Theorems, Electromagnetic Principles and Properties

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AC/DC Circuit Theorems, Electromagnetic Principles and Properties
AC/DC CIRCUIT THEOREMS, ELECTROMAGNETIC PRINCIPLES AND
PROPERTIES
A Research Paper on Energy By
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AC/DC Circuit Theorems, Electromagnetic Principles and Properties
INTRODUCTION
As a junior engineer in a global engineering consultancy firm and then transferred to
the Electrical Power team where there is need of contributing a broad understanding of
AD/DC circuit theorems, electromagnetics principles, and properties. There is need of
provision of information on the characteristics of circuits connected to either the AC or DC
buses from the flywheel-based energy storage system shown below:
Task 1.1
Operation of Motor/Generator in flywheel energy storage system
The motor/generator forms the electrical machines in the flywheel by working as a
motor to transfer electrical energy to this energy storage device and as a generator to restore
the energy stored into the flywheel. When acting as a generator, kinetic energy stored in the
rotor is transformed into electrical energy (Hans, 2014).
Figure 1: Basics of Motor/Generator in Flywheel

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AC/DC Circuit Theorems, Electromagnetic Principles and Properties
When performing as a motor, the supplied electrical energy to the windings of stator
is changed into mechanical energy leading to an increase in the velocity of the flywheel. It is
important to build a generator which generates high voltage that is greater than 10kV and low
current, which would lead to low power losses and high power supply. The electrical energy
input accelerates the mass to velocity through an integrated motor-generator. The energy is
discharged through reducing the kinetic energy by the use of the same motor-generator
(Kerry, 2013).
Low rotor losses, robust rotor structure, and high efficiency are the major
requirements for the motor/generator of the flywheel system. The figure below shows the rate
of radiated heat loss against rotor temperature:
The quantity of transfer of heat through radiation is minute except at high temperatures, and
high path of thermal through the bearings is minimal hence controlling the losses of the rotor
is important to prevent the rotor from overheating (Hans, 2014).
Task 1.2
Using Kirchhoff’s laws determine the magnitude and direction of the currents through each
resistor in the circuit below where the V1 and V2 of 12 V are connected to the DC pick- off
shown from the AC/DC/AC Power Converter above. From these currents determine the
voltage drops across each resistor: