Modeling and Control of Modern Electrical Energy Systems

1Power Electronics

This chapter reviews fundamentals pertaining to power electronics. The concept of power electronic conversion is first introduced which is followed by a short discussion on various types of power electronic switches and different types of power electronic converters (PECs). The chapter concludes by reviewing diverse applications of power electronics in power industry.

1.1 Power Electronics Based Conversion

A PEC (also called a power processor) uses power electronic switches (such as power diodes and power transistors) and passive circuit components (such as inductors and capacitors) to convert one form of electrical power to another form (e.g. dc to ac, ac to dc) or change its level (dc to dc) or change its frequency, phase, magnitude (ac to ac) or change the number of phases (single-phase to three-phase). In addition to this change, the converter can control the flow of power. The flow of power may be unidirectional (only from one side to other) or bidirectional (between both sides). The PEC achieves its objective by fast turning of the switches at a rate called the switching frequency.

Figure 1.1 shows a block diagram for a converter with its control system. The converter works as an interface between side A and side B. The controller is a feedback system that generates the control inputs based on the system measurements and references (also called set-points or desired values). The measurements generally are taken from both sides and may also be taken ...