Power Electronics

Power Electronics is a technology associated with flexible and efficient way of conversion and control of electric power. It is the application of electronic principles at the power level instead of at the signal level as used in electronic circuits. There are various power semiconductor
devices like SCR, GTO, PMOSFET etc. used in power electronics which work on the principles of electronics but they carry high power in contrast to low power semiconductors devices like diodes and BJT in electronics.

Power electronics plays an important role in modern power, energy conversion and control systems. The modern age of power electronics began with the introduction of power semiconductor devices in the late 1950s. Presently there are several types of power semiconductor devices available for high-power and high-frequency applications. The widely used power semiconductor devices are SCR, GTO (gate turn-off thyristor), power MOSFETs, and insulated-gate bipolar transistors (IGBTs).

Power Semiconductor Devices

The development of the power semiconductor devices has begun with the introduction of Silicon controlled rectifier in 1957. After that various devices have been developed. The below is the various popular power semiconductor devices.

1. Diode

2. SCR-Silicon Controlled Rectifier

3. GTO-Gate Turn Off thyristor

4. LASCR-Light Activated SCR 

5. RCT-Reverse Conducting Thyristor

6. Triac

7. Diac

8. MCT-MOS Controlled Thyristor

9. SITH-Static Induction THyristor

10. BJT-Bipolar Junction Transistor

11. Power MOSFET

12. SIT-Static Induction Transistor

13. IGBT- Insulated Gate Bipolar Transistor.

Various Power Electronics converters

(Goto Types of power electronic converters for full text)

Power electronics converters generally classified into following types

1. Rectifiers: AC to DC converters

2. Inverters: DC to AC converters

3. Choppers: DC to DC converters

4. AC voltage controllers: AC to AC converters

5. Cycloconverters: AC to AC converters

Applications of Power Electronics:

Power semiconductor device is the basic element in all power electronic conversion devices or power electronic circuits. These are used in power supplies, Electric Heating, Traction control, motor control systems, Battery chargers, VAR compensations, UPS - Uninterruptible power supplies, HVDC high-voltage DC transmission systems, and in many other power conversion applications.

Advantages and Disadvantages:

(Go to Advantages of Power Electronics for full article on advantages)

Power electronic conversion systems offer high efficiency, high reliability, less maintenance, reduced size, long life and fast dynamic response in comparison with the conventional system. The flexible speed control of the alternating current motors is made possible with the power electronics. However the power electronics has some disadvantages. The power electronics circuits may tend to generate harmonics, operate at low power factor and have low overload capacity. Despite these disadvantages the advantages far outweigh its disadvantages.