POWER SEMICONDUCTOR SYSTEMS I Author: Ales Havel Phone number: 4287 Headquarters: E227 Web page:

Presentation contents  Main types of converters  AC-DC converters  DC-DC converters 1-quadrant choppers Buck converter Boost converter Buck-Boost converter Resistance converters 2-quadrant choppers 4-quadrant choppers  DC-AC converters  AC-AC converters

Power converters  A power semiconductor converter is an electrical device for converting electrical energy.

1-Quadrant choppers Buck converter (step down chopper) Continuous load current Discontinuous load current Load voltage for continuous load current case: Load voltage for discontinuous load current case: Load current transistor time: Load current diode time:

1-Quadrant choppers Example 1: The Buck converter is working with the R + L + U i type of the load. The duty cycle of the converter (z) is 15% and the switching frequency (f) is 200Hz. Evaluate the U AV load voltage for these cases: (U = 100V, U i = 20V) 1)Continuous load current 2)Bypass diode conducting time is T/3. Solution: 1) 2)

1-Quadrant choppers Boost converter (step up chopper) Continuous load current Discontinuous load current Load voltage for continuous load current case: Load voltage for discontinuous load current case: Max. load current transistor time: Min. load current diode time:

1-Quadrant choppers Example 1: The Boost converter is working with the R + L + U i type of the load. The transistor conducting time T 1 = 1ms, the bypass diode conducting time is 1ms. The switching frequency (f) is 400Hz. Evaluate the U AV load voltage, if U = 100V and U i = 30V. Solution:

1-Quadrant choppers Resistance converter without capacitorResistance converter with capacitor Regulation range of equivalent resistance:

2-Quadrant choppers 2-Quadrant DC/DC converter with current reversion:

2-Quadrant choppers 2-Quadrant DC/DC converter with voltage reversion:

4-Quadrant chopper 2 ways of control: - Bipolar

4-Quadrant chopper 2 ways of control: - Unipolar

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