IGBT driving aspect Zhou Yizheng IGBT driving n

IGBT driving aspect Zhou Yizheng

IGBT driving n Driving voltage level n Effect of turn on/off ¬ Rge, Cge, Lg ¬ Driving capability n Isolation n Thermal n Protection ¬ Parasitic turn on ¬ Over voltage ¬ Short circuit/over current Copyright © Infineon Technologies 2009. All rights reserved.

Driving voltage level Tvj=125 C n Positive voltage Effect to Vcesat Vge ，Vcesat note：max. allowed Vge is 20 V Effect to short cicuit Vge ，Isc （tsc ） Copyright © Infineon Technologies 2009. All rights reserved. Tvj=125 C

Driving voltage level n Negative voltage ¬ To guarantee safety off state, avoid parasitic miller turn on ¬ Turn on delay increase (dead time) ¬ Slightly reduce tf and Eoff Miller capability effect ¬ Increase driving power Copyright © Infineon Technologies 2009. All rights reserved.

Effect of turn on/off n Rgon Control of dv/dt and di/dt with gate resistor Turn-on with smaller than nominal gate resistor: Turn-on with nominal gate resistor (datasheet value): Turn-on with larger than nominal gate resistor: dv/dt = 1. 4 k. V/µs di/dt = 8. 7 k. A/µs ICpeak = 2. 7 k. A Eon = 544 m. Ws dv/dt = 0. 9 k. V/µs di/dt = 6. 4 k. A/µs ICpeak = 2. 4 k. A Eon = 816 m. Ws dv/dt = 0. 3 k. V/µs di/dt = 3. 0 k. A/µs ICpeak = 1. 8 k. A Eon = 2558 m. Ws Copyright © Infineon Technologies 2009. All rights reserved.

Effect of turn on/off n Rgoff Control of dv/dt and di/dt with gate resistor • dv/dt is controllable with gate resistor. A larger resistor will result in a smaller dv/dt. • di/dt is only controllable if the gate voltage doesn’t drop below the Miller Plateau level before IC starts to decrease. This is in general the case for a gate resistor value close to the datasheet value. With larger resistors a control of di/dt starts to work. Copyright © Infineon Technologies 2009. All rights reserved.

Effect of turn on/off n Cge Independently control of dv/dt and di/dt Range Determined by Condition Influenced by Influence on 1 VGE < VGEth Ciss = const RG, CGE tdon 2 VGEth < VGEM Ciss = const RG, CGE di/ 3 VGE = VGEM VGE = const RG, CGC dv/ Copyright © Infineon Technologies 2009. All rights reserved. dt dt

For similar Eon, we can: Rge Cge Eon Di/dt Ipeak tdon Vge_p 4. 6 ohm 0 nf 650 m. J 3283 k. A/ us 1. 487 k. A 1. 76 us 13. 6 V 1. 7 ohm 200 nf 635 m. J 2492 k. A/ us 1. 386 k. A 1. 67 us 13. 7 V 1. 7 ohm 200 n. F 4. 6 ohm 0 n. F Copyright © Infineon Technologies 2009. All rights reserved.

For similar di/dt, we can: Rge Cge Eon Di/dt Ipeak tdon Vge_p 2. 6 ohm 0 nf 437 m. J 4270 k. A/ us 1. 639 k. A 1. 29 us 14. 0 V 1. 7 ohm 46 nf 386 m. J 4324 k. A/ us 1. 635 k. A 1. 23 us 15. 0 V 1. 7 ohm 46 n. F 2. 6 ohm 0 n. F Copyright © Infineon Technologies 2009. All rights reserved.

Rge vs. Cge n Using Cge shows better Eon*di/dt coefficient n Using Cge can significantly increase driving power P=∆U*(Qge+Cge*∆U)*f n Using Cge can significantly increase driving peak current, require more powerful driver (output peak current capability) n The tolerance of Cge should be taken care when used in IGBT paralleling application n Using Cge may cause gate current oscillation, which leads to higher gate peak voltage. Copyright © Infineon Technologies 2009. All rights reserved.

Cable length influence With long cable With short cable Calbe Rge Short Long Cge Eon Di/dt 0. 9 ohm 0 nf 196 m. J 0. 9 ohm 0 nf 87 m. J Ipeak tdon Vge_p 6128 k. A 1. 978 k /us A 0. 92 us 14. 7 V 6920 k. A 2. 220 k /us A 0. 92 us 18. 3 V Copyright © Infineon Technologies 2009. All rights reserved.

For similar Eon, we can: n With fixed Cge Calbe Rge Short Long Cge Eon Di/dt 0. 9 ohm 22 nf 210 m. J 1. 7 ohm 22 nf Ipeak tdon Vge_p 5882 k. A 1. 908 k /us A 0. 92 us 17. 0 V 231 m. J 5587 k. A 1. 874 k /us A 1. 21 us 17. 5 V Eon Di/dt tdon Vge_p n With fixed Rge Calbe Rge Cge Ipeak Short 1. 7 ohm 22 nf 351 m. J 4717 k. A 1. 711 k /us A 1. 17 us 15. 8 V Long 1. 7 ohm 91 nf 347 m. J 4065 k. A 1. 673 k /us A 1. 39 us 15. 6 V Copyright © Infineon Technologies 2009. All rights reserved.

Cable length influence n Cable length (Lg) shows similar Eon*di/dt coefficient as Rge, This mainly due to Lg effect both during di/dt period and dv/dt period (same as Rge) n Long cable significantly induce the turn on delay time n Long cable is a EMI receiver, which can cause Vge spike and unstable. n Loosing gate cable inductance will significantly increase Eon, which should especially paid attention in active adaptor design. Adaptor board Rge Cge Eon Di/dt Ipeak Active 1. 0 ohm 0 nf 332 m. J 5650 k. A/us 1. 708 k. A Passive(8 mm) 1. 0 ohm 0 nf 187 m. J 7700 k. A/us 1. 895 k. A Long cable should be avoid to be used. But loosing gate inductance should also be paid attention Copyright © Infineon Technologies 2009. All rights reserved.

Effect of turn on/off n Driving capability ¬ Peak current capability l Maximum driver peak current Slow down turn on/off speed Driver losses U = 30 V @ 15 V switching ¬ Power capability l Driver power Vge goes down Power supply losses Copyright © Infineon Technologies 2009. All rights reserved.

Effect of turn on/off n Turn on/off criteria Redundant information on di/dt and dv/dt 3 Diode SOA ! 2000 IR(t) [A] 2 ! 1 1000 0 locus i. R(t)*v. R(t) 2 0 1 0 0 Copyright © Infineon Technologies 2009. All rights reserved. 1000 2000 VR(t) [V] 3 3000

Isolation + Optocoupler § High isolation capability Optical Fiber § Aging of electrical characteristic § Reduced reliability due to aging § No energy transmission Monolithic Level Shifter § Cost effective § No galvanic isolation § Integration of logic suitable § EMI sensitivity § No energy transmission Discrete Transformer § Very high isolation Capability § Energy transmission possible Coreless Transformer (CLT) § High isolation capability § Expensive § Device Volume § No energy transmission § Very cost effective § Easy integration of logic function Copyright © Infineon Technologies 2009. All rights reserved.

Isolation n Isolation transformer ¬ Isolation test ¬ Partial discharge test ¬ Parasitic capacitor

Thermal n Influenced parameters o Module case temperature o Driving power (switching frequency, Qg) o Driving peak current n Sensitive parts o Gate resistor o Booster o Power supply o Fiber Copyright © Infineon Technologies 2009. All rights reserved.

Thermal n If system internal ambient temperature is known. n From delt Tca, we can check temperature rise due to module itself heating n Adding temperature rise due to driving signal, real driver board temperature can be gotten. System cooling can significant improve driver cooling condition Copyright © Infineon Technologies 2009. All rights reserved.

Protection n UVLO n Interlock / generating deadtime n Vge over voltage n Parasitic turn on n Short circuit protection n Over voltage protection (for short circuit off) ¬ Active Clamping ¬ DVRC (Dynamik Voltage Raise Control) ¬ di/dt-Feedback ¬ Soft-Shut-Down ¬ Two-Level Turn-off Copyright © Infineon Technologies 2009. All rights reserved.

Protection n UVLO ¬ Avoid driving IGBT with low voltage causing thermal issue ¬ Avoid series break down n Interlock / generating deadtime ¬ Avoid short through by software mistake ¬ Hardware deadtime should be shorter than software deadtime Copyright © Infineon Technologies 2009. All rights reserved.

Protection n Vge over voltage ¬ Limitation of increase of gate voltage due to positive feedback over C GC and due to di/dt ¬ Limitation of short circuit currents Methode 1 Gate-Supply Clamping Methode 2 Gate-Emitter Clamping Copyright © Infineon Technologies 2009. All rights reserved.

Protection n Parasitic turn on ¬ minus voltage off ¬ separate gate resistors, using small Rgoff and big Rgon ¬ Additional gate emitter capacitor to shunt the Miller current ¬ Active Miller clamping Copyright © Infineon Technologies 2009. All rights reserved.

Protection n Short circuit protection o Desaturation detect Vce Ic SC I OC Copyright

Protection n Short circuit protection o Desaturation detect Based on fixed reference voltage Based

Protection n Short circuit protection o Desaturation detect o Over current protection? – Noise immunity is poor – Blanking time hard to set for fixed reference voltage concept, especially for high voltage module – Current protect point hard to be accurate ¬ Directly detect collector current ¬ Digital controller to detect di/dt ¬ By system current sensor Copyright © Infineon Technologies 2009. All rights reserved.

Protection n Over voltage protection ¬ Active clamping Copyright © Infineon Technologies 2009. All

Protection n Over voltage protection ¬ DVRC (Dynamic Voltage Raise Control) u. GE(t) i. C(t) UF 4007 100 p. F dic/dt=11 k. A/µs @ Tj=25°C 3 x. SM 6 T 220 A IRFD 120 UF 4007 47 R UAC 4 x. SM 6 T 220 A +16 V RMO u. CE(t) RG=3. 6 W EOFF=0. 9 J BYD 77 S 56 ZPD 16 44 H 11 MFP-D PWM 15 R BYD 77 MFN-D 45 H 11 URAC RAC=15 W RG=1. 5 W FZ 2400 R 17 KE 3 u. GE(t) i. C(t) dic/dt=3. 4 k. A/µs @ Tj=25°C -16 V u. CE(t) Copyright © Infineon Technologies 2009. All rights reserved. RG=13 W EOFF=1. 95 J

Protection n Over voltage protection ¬ di/dt protection Copyright © Infineon Technologies 2009. All

Protection n Over voltage protection ¬ Soft shut down Copyright © Infineon Technologies 2009.

Protection n Over voltage protection ¬ Two level turn off Driver Out IC VGE Driver Out VCE Without Two-Level Turn-Off VCE reaches 1000 V IC VGE VCE With Two-Level Turn-Off VCE reduced to 640 V Copyright © Infineon Technologies 2009. All rights reserved.