Concordia University
Department of Electrical and Computer
Engineering
Power Electronics (I) ELEC-433/6411
Week 2
Overview of static power switches
(Chapter 2)
, Outline
• Introduction: Classification of switches
• Main power semiconductor switches:
– Diodes, thyristors and power control characteristics;
– Controllable switches: BJT, MOSFET, IGBT and GTO;
• Practical switching characteristics and losses
• Comparison of controllable switches
• Heat sink and gate drive circuits.
2
, Classification of switches
• According to the degree of controllability:
• Uncontrolled: On and Off states controlled by the
power circuit (Diode).
• Semi-controlled: Turned On by a control signal but
turned off by the power circuit (SCR thyristors).
• Controlled switches: Can be turned On and Off by
a control signal (Transistors and GTO thyristors)
For analysis purposes power switches are usually
considered ideal: Instantaneous, lossless, and
infinite current and voltage handling capability.
3
Department of Electrical and Computer
Engineering
Power Electronics (I) ELEC-433/6411
Week 2
Overview of static power switches
(Chapter 2)
, Outline
• Introduction: Classification of switches
• Main power semiconductor switches:
– Diodes, thyristors and power control characteristics;
– Controllable switches: BJT, MOSFET, IGBT and GTO;
• Practical switching characteristics and losses
• Comparison of controllable switches
• Heat sink and gate drive circuits.
2
, Classification of switches
• According to the degree of controllability:
• Uncontrolled: On and Off states controlled by the
power circuit (Diode).
• Semi-controlled: Turned On by a control signal but
turned off by the power circuit (SCR thyristors).
• Controlled switches: Can be turned On and Off by
a control signal (Transistors and GTO thyristors)
For analysis purposes power switches are usually
considered ideal: Instantaneous, lossless, and
infinite current and voltage handling capability.
3
