Power electronics deals with the applications of solid state electronics for the control and conversion of electric power. The conversion systems require switching power semiconductor devices on and off.
The key components of an electric drive controlled by a power semiconductor converter are illustrated in the figure below:
The converter regulates the flow of power from the source to the motor in such a way that the motor speed-torque and speed-current characteristics become compatible with the load requirements.
The low-voltage control unit, which may consist of integrated transistorized circuits or a microprocessor, is electrically isolated from the converter motor circuit and controls the converter. The sensing unit, required for closed loop operation or protection or both is used to sense the power circuit’s electrical parameters, such as converter current, voltage and motor speed. The command signal forms an input to the control unit, adjusting the operating point of the drive. The complete electric drive system is treated as an integrated system.
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