電力電子元件簡介 - 清華大學電機系-NTHUEE

1 Introduction to Power Electronic Devices C. M. Liaw Department of Electrical Engineering National Tsing Hua University Hsinchu, Taiwan, ROC.. ( Power diode) ( SCR). Power diode SCR. AC P. AC. source source Load Load Firing circuit Diode: Uncontrolled turn-on and SCR: Controlled turn-on and turn-off uncontrolled turn-off .. Page 1. ( ). Voltage/current ratings Switching frequency (speed). Switching time On-state resistance (or on-state voltage/current).. (A) (Thyristor) (Silicon Controlled . Rectifier, SCR) : Controlled turn-on, uncontrolled turn-off (B) (Bidirectional Thyristor TRIAC). (C) GTO (Gate Turn-off Thysistor). (D) (Integrated Gate-Commutated Thyristor, IGCT): It is introduced by ABB in 1997.

2 It is a high-voltage, hard-driven, asymmetrical-blocking GTO with unity gain. The gate drive circuit is built-in on the device module. (E) (Power BJT) : Current control device (F) IGBT (Insulated Gate Bipolar Transistor): - Combines the conduction characteristic of BJT and the control characteristic of the MOSFET. (G) MOS (MOS -controlled Thyristor, MCT): - Combines the load characteristic of the thyristor and the control characteristic of the MOSFET. - Low on-state voltage (H) (Power MOSFET) : Voltage control device (I) . Page 2.. (1) Uncontrolled turn-on and off: (diode). (2) Controlled turn-on and uncontrolled turn-off: (SCR). (3) Controlled turn-on and off (Controllable switches): (GTO, IGCT, MCT, BJT, IGBT, MOSFET).

3 (4) Continuous gate signal requirement: (IGCT, BJT, IGBT, MOSFET). (5) Pulse gate signal requirement: (MCT, SCR, TRIAC, GTO). (6) Bipolar voltage-withstanding capability: (SCR). (7) Unipolar voltage-withstanding capability: (GTO, IGCT, MCT, BJT, IGBT, MOSFET). (8) Bidirectional current capability: (TRIAC). (9) Unidirectional current capability: (SCR, GTO, IGCT, MCT, BJT, IGBT, MOSFET, diode). Power Semiconductors Classification of SiC. state-of-the-art Power Semi- conductors Page 3.. ( ). Power Input Power Output Output source source filter Converter filter (to load). (AC, DC). ( / . ( ) Loads: ). Power supplies Switching Feedback Command Control Signal Motor drives Generator ( ).

4 : : (Cycloconverter). ( ). (Converter): Phase control, integral cycle control (Inverter): VVVF, VVFF. (Chopper): PWM control, FM control Page 4. ?? . (1) . (2) .. (3) . (4) . (5) ( ) . (6) . (7) . (8) . (9) ( ) .. Power diodes: General purpose (for high-power rectification). High speed (for switching application). Schottky (for extra-low voltage rectification). Thyristors Power transistors Page 5. SCR ( ). (Thyristor)- (Silicon Controlled Rectifier, SCR) : Controlled turn-on, uncontrolled turn-off Construction, symbol, equivalent circuit, triggering control, v-i characteristics: A A A. A. P P. N Q1. N N. G. G. P P P i c1 = ib2. G i c2 = ib1.

5 G Q2. N N. K. K K. K. Two-transistor model Page 6. SCR . v AK > V RB (V RWM ) Breakdown i AK. A. i AK 0. P. N. RB. - G FB. P IH iG1 > iG2 > iG3. vAK. N. RB + VRB (VRWM ). VFB (VBO ). K. SCR . : i AK. A. i AK. P. FB. N + IH iG1 > iG2 > iG3. G RB VRB (VRWM ) vAK. P. N. FB - VFB (VBO ). iGK. K. Page 7. Two-transistor model ib i c ib i c (Current is cumulatively amplified). Normally triggered: v AK > 0 i GS > 0. A. Abnormally triggered: High dv/dt High temperature Q1. v AK > V FB. i c1 = i b 2. i c2 = i b1. Q2. G. K.. Turn on: v AK > 0 i GS > 0. Turn off: i AK < I H ( Holding current ).. i AK. V FB V RB . VRB (VRWM ). IH iG1 > iG2 > iG3. vAK.

6 VFB (VBO ). Page 8. Gate SCR . (Shockley diode). on off: v AK V FB ON , i AK < I H OFF. A K. Triac (AC Thyristor). A three-terminal, five layer, bilateral semiconductor device. Bidirectional TRIode AC thyristor. TRIAC. Tab electrically connected to T2. T1. T2. G. Page 9. Triac . TRIAC. Power supply IT48TH. - + - +. T1 T2 G. TRIAC. T2. A three-terminal, five layer, bilateral semiconductor device. P2 N3. T 2 T1 : P2 - N2 - P1 - N1. T 1 T 2 : P1 - N2 - P2 - N3. N2. P1. N1 N4. T1 G. Page 10. TRIAC: SCR . bidirectional current capability . G. T1 ( A ) T2 ( K ) T1 T2.. G. v AK > 0 i GK > 0. Turn on: v AK < 0 i GK < 0. Turn off: i AK < I H ( Holding current ).

7 I AK. + iT =. T2 iT 2 - T 1. vT = VRB IH iG 1 > iG 2 > iG 3. vT 2-T1 G vT. T1. VFB 2 -T1. - iG (v AK ). Typical Applications of SCR and TRIAC. n Converter power control (1) Phase control (2) Integral cycle control n SSR (Solid State Relay) or AC Switch Page 11. (Controllable Switches). iT. (1) Forced-commutated SCR Control +. vT. (2) BJT, MOSFET, IGBT, MCT, .. signal - pT =vT iT.. : Switching speed -- : Switching losses . (1) Off : Leakage current vT iT. V ON. (2) On : R ON. , V ON. t p T = v T iT. iT. R ON. V ON Conduction loss . turn-on turn-off (Switching losses). Power BJT. Current-controlled device IB C. B. IC. E. Turn on: I B I C ,sat / b min Page 12.

8 Power BJT. Voltage ratings: (primary breakdown). BV SUS , BV CEO , BV CBO. VCB , max (E is open circuited). VCE , max (B is open circuited). VCE ,max when I C 0. Secondary breakdown: Caused by large di/dt at turn-on instant. Power BJT. b is smaller compared with small-signal BJTs. Hard saturation and quasi-saturation: Quasi-saturation: iC. I B = I C ,sat / b min IB. Hard-saturation: Conduction loss v CE. Switching speed I B > I C , sat / b min Page 13. Power MOSFET. Voltage-controlled device Turn on: v GS > v GS , th i G ,steady - state 0 (very small). D. v GS. v GS G. v GS , th Parasitic C S. Power MOSFET. v GS ,max > v GS > v GS ,th v GS - i D ,sat - , Ron , Pswitching - R DS ,on = k BV DS.

9 2 .5 ~ 2 . 7. n Light load: Switching loss dominant : iD 1 / Ron v GS P g = Q g vGS f sw vGS2 > vGS1. Q g = total gate charge vGS1. n Heavy load: iD2 > iD1. iD1. Conduction loss dominant : v GS - R DS ,on v DS. Page 14. Cool MOSFET. It is a new revolutionary technology for high voltage power MOSFETs. It implements a compensation structure in the vertical drift region of a MOSFET in order to improve the on-state resistance. R DS ,on , Q g , q JA slightly higher (~ 10%). Pulse current rating is lower. Page 15. Page 16. Page 17. Page 18. Page 19. Power MOSFET Power BJT . Power MOSFET R ON. (Enhancement mode). V ON. {. D v GS > v GS ,th , i G , steady - state 0( very small ).}

10 G Turn on: . switching speed +. {. v GS. - S VON = 0, RON .. : Thermal run away . Power BJT. {. I B > I C,sat / bmin , . C Turn on: . B IC switching speed MOSFET . {. IB E V ON = V CE , sat , R ON.. MOSFET . : Thermal run away . Page 20. IGBT (Insulated-Gate Bipolar Transistor). MOSTFET + BJT. IGBT (Insulated Gate Bipolar Transistor): - Combines the conduction characteristic of BJT. and the control characteristic of the MOSFET. Symbol and equivalent circuit: C(D). C(D) C(D). C(D). G G G. G. E(S) E(S). E(S). E(S). v GS. C(D). G. E(S). Printed circuit .. board Damping filter Page 21. MCT (MOS-controlled Thyristor). MOSTFET + Thyristor Combines the load characteristic of thyristor and the control characteristic of MOSFET.}}}