TABLE OF CONTENTS AC and DC motor variable-speed drive systems are the main projects of the power electronics . Energy storage in AC and DC motors has recently been investigated and discussed.
AC motors can be supplied by fixed frequency (e.g. f = 50 or 60 Hz) power supply, but its speed cannot be changed. An AC motor variable-speed drive system performs in adjustable speed, so that its power supply frequency is changeable. AC motors working in variable-speed drive system are supplied by choppers, DC/AC pulse-width modulated (PWM) inverters and AC/AC (AC/DC/AC) converters. Therefore, this system is working in discrete state. We can call these AC motor power supplies as discrete AC power supply sources.
DC motors can be supplied by fixed DC voltage power supply, but its speed cannot be changed (under the condition of fixed field flux). A DC motor variable-speed drive system performs in adjustable speed, so that its power supply voltage is changeable. DC motors working in variable-speed drive system are usually supplied by choppers, AC/DC rectifiers and DC/DC converters. Therefore, this system is working in discrete state. We can call these DC motor power supplies as discrete DC power supply sources.
AC and DC motors are an important equipment to convert the electrical energy to mechanical energy. Variable-speed drive system is the main project of the power electronics . Energy storage in motors has recently been investigated and discussed. We can apply the energy factor ( EF) to demonstrate the motor drive system s characteristics.
Although there...
