5EE1 POWER ELECTRONICS-III

Unit-1

Power Semiconductor Devices:

Characteristics of Power Transistor, Thyristor, GTO, Power

MOSFET and IGBT. Two-Transistor Model of Thyristor.

Unit-2

SCR:

Construction and characteristics, specification and ratings, pulse transformer, optical

isolators, methods of turn on: R, RC, UJT relaxation oscillator, Rating extension by series and

parallel connections, string efficiency. Protection of SCR-Protection against over voltage, over

current, dv/dt, di/dt, Gate protection.

Unit-3

Converters-I:

Single Phase half & full wave converters with RL load, Single phase dual

converters, Three phase half wave converters, Three phase full converters with RL load, Three

phase dual converters.

Unit-4

Converters-II:

Single and three-phase semi converters with RL load. Power Factor

Improvement-Extinction angle control, symmetrical angle control, pulse width modulation

control and sinusoidal pulse width modulation control. Inversion operation. Effect of load and

source impedances.

Unit-5

DC-DC Converters: Choppers:

Step Up/Down Copper, Chopper Configurations, analysis of