Introduction to Power Electronics

Introduction to Power Electronics

  • Power Electronics (PE) merges the field of electric power, solid-state semiconductor power devices (electronics), and control systems. Power engineering deals with the static and rotating devices for generating, transmitting, and distributing electric power.  The semiconductor devices and circuits are used to convert the power to meet the required control objectives.  
  • Therefore, PE may be described as the application of solid-state power semiconductor devices to control and convert electric power.  In an electrical system, voltage, frequency, and current will be regulated to control the flow of power by PE devices, as shown in Figure 1.  A power-processing unit, i.e., power electronics circuit with a control algorithm, is present between source and load to save energy.

Basic power supply schematic

Figure 1: Basic power supply schematic

Difference between power electronics versus linear electronics?

  • In electronics, it is possible to handle a low voltage range, i.e., ±5 volts, ±15 volts, 3.3 volts, etc. The current rating is also nearly in the range of microampere, mill ampere, and a few amperes.  

  • Therefore, power levels are a few watts or a few milliwatts. The linear amplifier is mostly emphasizing signal amplification. Thus, transistors are operated strictly in the linear (active) zone.

  • In the case of power electronics, the same electronic circuit is normally designed to handle higher current (increasing cross-sectional area) and higher voltage (increasing length).

  • Semiconductor switches operated in the saturated (ON) and cut-off (OFF) mode only. Therefore, losses in the system are reduced. The system offers better efficiency in comparison with linear electronics.