lecture3(Cnt) - Very short switching Very low loss Power...

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1 Page 1 Use Power Semiconductor Devices for Switching Diodes Thyristors Gate Turn-off Thyristors Triacs Power Transistors Insulated Gate Bipolar Transistors Smart Power Devices 3. Control of Drives 3. Control of Drives    
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2 Page 2 Diodes Current flows in ONE direction only For protection Thyristors Turned on when fires at the gate. A pulse is used as forward bias Gate Turn-off Thyristors Turned off by a negative current at the gate Gate controlled feature permits power switching Power Semiconductor Devices Power Semiconductor Devices
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3 Page 3 Triacs Consists of two thyristors in reverse parallel Can be turned on in both directions For controlling motors and heating loads Power  Power  Semiconductor Devices Semiconductor Devices
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4 Page 4 Power Transistors Used for switching When the base current is high, it is ON When the base current is zero, it is OFF Switching is faster than thyristors High losses Power MOSFETs Similar to above
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Unformatted text preview: Very short switching Very low loss Power Power Semiconductor Devices Semiconductor Devices 5 Page 5 Insulated Gate BipolarTransistors (IGBT) Also for switching Much less control current Improved switching Switching is faster than thyristors High losses Smart Power Devices Can monitor & control operation Can show status e.g. has simultaneous control & protection Power Semiconductor Devices Power Semiconductor Devices 6 Page 6 Electrohydraulic/Pneumatic Control Spool Valves Hydraulic Cylinders Solenoids Controllers - PLCs or others Control Valves Manual Solenoid Operated Servovalves Actuator Controllers Actuator Controllers 7 Page 7 Electrohydraulic Control More Powerful More Precise Electropneumatic Control Faster More Environmental Friendlier Cheaper Comparison Comparison...
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This note was uploaded on 11/09/2009 for the course ENG 91301 taught by Professor Lui during the Spring '08 term at Hong Kong Institute of Vocational Education.

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lecture3(Cnt) - Very short switching Very low loss Power...

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