Voltage, Current and Temperature Measurement Concepts Enabling Intelligent Gate Drives
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
ECPE Workshop Munich
Electronics around the power switch:
Gate drives, sensors and control
2011/06/29-30
Voltage, Current and Temperature Measurement Concepts
Enabling Intelligent Gate Drives
Yanick Lobsiger, Johann W. Kolar
Swiss Federal Institute of Technology (ETH) Zurich
Power Electronic Systems Laboratory
www.pes.ee.ethz.ch | lobsiger@lem.ee.ethz.ch
Motivation 2
Intelligent Gate Drive Need for measurements
Integratable in gate driver, external circuits
Digital control unit (FPGA, CPLD, DSP) and IGBT; typ. without galvanic isolation
with computing power close to the
power semiconductor Current measurement concepts
Programmable output characteristics Collector current: iC
[Hemmer2009] Collector current slope: diC/dt
Advanced control (diC/dt, duCE/dt)
[Kuhn2008]
Voltage measurement concepts
Extended and adjustable protection
Collector-Emitter voltage: uCE
functionality (short-circuit, over-current,
overvoltage-limiting, health monitoring, …) Collector-Emitter on-state voltage: uCE,on
Extensive communication possibilities Collector-Emitter voltage slope: duCE/dt
(digital transmission bus with control unit)
Temperature measurement concepts
Junction temperature: Tj
InPower digital gate driver
Y. Lobsiger | 2011/06/30 @ ECPE Workshop Munich
Current measurement: iC 3
Shunt resistor
Semikron Semitrans® Infineon MIPAQ™ IGBT module
IGBT module with with integrated shunts
integrated shunts (in the output phases)
uS(t) ≈ RS·iC(t) + LS · diC(t)/dt
uS,f(t) = RS·iC(t) (for Rf· Cf = LS / RS)
(+)
(–) Simple, cheap, passive
(low noise & low disturbance)
Losses: PL ≈ RS · iC2
Possibility of integration in IGBT module
Low losses = low amplitude resolution
(Infineon MIPAQ™, Semikron Semitrans®)
Temperature drift or busbar (well dissipated losses)
Parasitic (commutation) inductance LS DC & AC measurement uS,f(t) ~ iC(t)
Accurate compensation needed (high bandwidth due to compensation of LS)
Y. Lobsiger | 2011/06/30 @ ECPE Workshop Munich
Current measurement: iC 4
Current sense IGBT
(split-cells: nS / ntot)
Mitsubishi Electric IGBT module with integrated
uS(t) = RS·iS(t) current sense IGBT and corresponding terminals
≈ RS·iC(t) ·nS /ntot
(typ.: nS /ntot = 1/100 … 1/1000)
(+)
Simple, passive
(–) (low noise & low disturbance)
High accuracy = low resolution Integrated in IGBT module
Small RS is needed for right scaling (Fuji Electric, Mitsubishi Electric)
Cost, rarity High bandwidth
Only few types available AC & DC measurement: uS(t) ~ iC(t)
Often no alternatives Low losses
Y. Lobsiger | 2011/06/30 @ ECPE Workshop Munich
Current measurement: iC 5
Rogowski coil (passive integration) Amplitude characteristic of ur / iC | uf / ur | uf / iC
(+)
Simple, cheap, passive
ur(t) = Mr·diC(t)/dt (low noise & low disturbance)
High upper bandwidth (typ. fu > 50 MHz)
(-) Integration in PCB / IPEM possible
No DC current measurement High freq. AC measurement: ur(t) ~ iC(t)
(high lower bandwidth fc) Low losses
Typ. too low amplitude resolution Isolated, no saturation effects
Signal integration needed No additional commutation inductance
Y. Lobsiger | 2011/06/30 @ ECPE Workshop Munich
Current measurement: iC 6
Rogowski coil (activeintegration) Amplitude characteristic of ur / iC | ui / ur | ui / iC
(+)
Simple, cheap
ui(t) ≈ Mr / (Ri·Ci) ·iC(t) (for fiC > fc) High upper bandwidth (typ. fu > 50 MHz)
(-) Small lower bandwidth (typ. fc < 50 Hz)
Active (noise) Integration in PCB / IPEM possible
Parasitic effects of operational amplifier Low to high freq. AC measurement: ui(t) ~ iC(t)
Bias current, offset voltage (Rd avoids DC-drift) Low losses
Limited gain-bandwidth-product Isolated, no saturation effects
Limited lower bandwidth fc, no DC No additional commutation inductance
Y. Lobsiger | 2011/06/30 @ ECPE Workshop Munich
Current measurement: iC 7
Integration of Rogowski coil to
IPEM
PCB
[Bortis2008]
PCB integrated Rogowski coils
around single screwed terminals
[Xiao2003] [Bortis2008]
Prototype of IPEM embedded PCB integrated Rogowski coil
Rogowski coil sensor around multiple screwed terminals
Y. Lobsiger | 2011/06/30 @ ECPE Workshop Munich
Current measurement: iC 8
IGBT bonding inductance (-)
Auxiliary (kelvin) emitter terminal needed
Dependency on gate current
Resettable integrator circuit beneficial
Parasitic effects of operational amplifier & switch
Bias current, offset voltage (Rd or si to avoid DC-drift)
Limited gain-bandwidth-product
Limited lower bandwidth fc, no DC measurement
Parasitic inductance LE integrated in IGBT module
Depencency on tolerances of manufacturing process
for accurate measurements without calibration
(+)
Simple, cheap
uEe(t) = -LE·diC(t)/dt High upper bandwidth (typ. fu > 50 MHz)
Small lower bandwidth (typ. fc < 50 Hz)
ui(t) ≈ (LE·iC(t) ) / (Ri·Ci) Parasitic inductance LE integrated in IGBT module
no sensing hardware needed
si is used to minimize the influence of iG Low to high freq. AC measurement: ui(t) ~ iC(t)
(si closed during the gate current transients, Low losses
i.e. before the switching transients of iC) No additional commutation inductance
Y. Lobsiger | 2011/06/30 @ ECPE Workshop Munich
Current measurement: iC 9
Giant Magnetoresistive (GMR) Sensor Prototype of
Sensitec’s GMR
High resistance [Shah2004] Low resistance current sensor
(CMS) fu ≈ 4 MHz
[Slatter2011]
[Olson2003] (-)
Additional commutation inductance
(+) Limited upper bandwidth (cf. Rogowski coil)
DC to AC current measurement Sensitec CMS series: fu ≈ 4 MHz
Possibility of integration to IPEM Active (noise)
Low losses Evaluation & compensation circuit needed
Y. Lobsiger | 2011/06/30 @ ECPE Workshop Munich
Current derivative measurement: diC/dt 10
Bonding inductance Rogowski coil
uEe(t) = – LE·diC(t)/dt ur(t) =Mr·diC(t)/dt
(+) (+)
Simple, cheap, no sensing hardware needed Simple, cheap
Accurate (direct signal measurement) Accurate (direct signal measurement)
(-) (-)
Auxiliary (kelvin) emitter terminal needed Rogowski coil needed
Dependency on manufacturing process Dependency on stray field
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichCurrent derivative measurement: diC/dt 11
Passive derivation of current signal uin Active derivation of current signal uin
uf(t) = a · duin(t)/dt = b · diC(t)/dt (for fin < fc) ud(t) = a · duin(t)/dt = b · diC(t)/dt
(+) (+)
Simple, cheap Simple, cheap
Passive (low noise) High amplitude
(-) (-)
Indirect measurement (derivation) Indirect measurement (derivation)
Low amplitude resolution Active (noise)
High amplitude = low bandwidth High amplitude = high noise
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichVoltage measurement: uCE 12
Compensated passive voltage divider
(+)
Simple, cheap
Passive (low noise)
High bandwidth, adjustable gain
[Wang2009]
uCE,L(t) = RL / (RH + RL) ∙ uCE(t) (-)
Additional IGBT output capacitance
(for CL = CH ∙ RH / RL) Blocking voltage of RH is about uCE,max
Typ. no additional capacitor CH needed as the parasitic capacitances of RH and the PCB layout are
high enough for compensation with CL
Minimal possible output capacitance
High impedance
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichVoltage measurement: uCE,on 13
Decoupling diode D
uCE,lim(t) = uCE(t) + uD,f (for uCE < u+ - uD,f)
uCE,lim(t) = u+ (for uCE >= u+ - uD,f)
Voltages of uCE above u+ - uD,f are clipped by
[Huan2007]
diode D that is then in blocking state
Compensation of uD,f is needed if the
exact value of uCE,on is needed
(-) (+)
Offset uD in measured voltage uCE,lim Simple, cheap
Dependency of uD on Passive (low noise)
Temperature TD High bandwidth
Current iD
High blocking voltage of diode D needed
(about uCE,max)
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichVoltage measurement: uCE,on 14
Limiting Z-diode
uCE,lim(t) = uCE(t) (for uCE < uZ + uD,f)
uCE,lim(t) = uZ + uD,f (for uCE >= uZ + uD,f)
Voltages of uCE above uZ + uD,f are clipped by
Z-diode Z and diode D
[Carsten1995]
(-) (+)
Low bandwidth (Z and D conducting Simple, cheap
before vCE drops below vZ + vD,f)
Passive (low noise)
Charge recovery of diodes
Low-pass of R and diode’s capacitances
No offset voltage in uCE,lim
High voltage rating for R (about uCE,max) Low blocking voltages of D & Z needed
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichVoltage measurement: uCE,on 15
Parallel switch S
uCE,lim(t) = min(uCE(t),ulim)
When s = 1 then: uCE,lim = uCE,on
[Kaiser1987]
(+) (-)
Direct connection when switch is Switch S needs same blocking voltage
closed (s = 1) (low noise) as IGBT (about uCE,max)
No offset voltage in uCE,lim Separate switching signal s needed
Derived passively by uCE [Kaiser1987]
Provided by digital control unit
Limited bandwidth due to delayed
switching of S
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichVoltage derivative measurement: duCE/dt 16
Passive derivation of voltage signal uCE Amplitude characteristic
[Wang2009]
uf(t) ≈ Rf ∙ Cf ∙ duCE(t)/dt
(+)
(for ufTemperature measurement: Tj 17
NTC thermistor: Rt = f(T) Sensing pn-diode: vf = f(T,if)
On-chip integration On-chip integration
Distance to IGBT cell Arranged directly next to IGBT cell
Typ. resolution: Rt / T ≈ 10kΩ / 200 ºC Typ. resolution vf / T ≈ 1.7 mV / ºC
Powerex IGBT
module with
integrated NTC
thermistor Fuji Electric IGBT
[Motto2005] module with int. Fuji Electric
on-chip sensing diodes [Ichikawa2009]
[Motto2005]
Infineon Datasheet [Schmidt2009] [Ichikawa2009] [Maxim AN3500,2005]
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichTemperature measurement: Tj 18
Gate driving characteristic: IGBT output characteristic: Tj = f(iC, vCE,on)
Tj = f(vGE,th) - resolution: typ. 1 V /100 ºC Need for and dependency on
(depending on IGBT) iC & vCE,on measurements
Infineon
datasheet
f(td,on, td,off) - resolution: typ. < 2ns / ºC
(depending on IGBT & gate current)
[Kim1998] [Schmidt2009]
Evaluation by DSP / FPGA in
interpolated 3D-table
Not usable around the crossover-point
between positive and negative temperature
coefficient, that is typ.
above nominal current for PT IGBTs
[Kuhn2009] [Kuhn2009] well below nominal current for NPT IGBTs
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichTemperature measurement: Tj 19
Internal gate resistor: Tj = f(RG,int) Thermocouple (e.g. Pt100)
Integrated in IGBT module Glued on the IGBT chip
No additional sensor needed Glue with low thermal impedance needed
Very small distance to IGBT junction Location close to IGBT chip center
Connection to int. gate terminal needed Large time constant of thermocouple
Low temperature dependency of RG,int (≈ 200 ms)
Positive temp. coefficient Switching transients of Tj can not be measured
Precise acquisition system needed High accuracy for Tj,avg measurement
Opening of IGBT module needed
[Brekel2009] [Brekel2009]
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichLiterature 20
[Bortis2008] D. Bortis, J. Biela and J. W. Kolar, “Active gate control for current balancing of parallel-connected IGBT modules in solid-state
modulators,” IEEE Transactions on Plasma Science, vol. 36, no. 5, pp. 2632—2637, Oct. 2008.
[Brekel2009] W. Brekel, Th. Duetemeyer, G. Puk and O. Schilling, “Time resolved in situ Tvj measurements of 6.5kV IGBTs during inverter
operation,” Proc. of the Power Conversion Intelligent Motion Conf. (PCIM Europe), pp. 808—813, 2009.
[Carsten1995] B. Carsten, “A “clipping pre-amplifier” for accurate scope measurement of high voltage switching transistor and diode conduction
voltages,” Proc. of the 31st Int. Power Conversion Electronics Conf. and Exhibit, pp. 335—342, 1995.
[Huan2007] F. Huang and F. Flett, “IGBT fault protection based on di/dt feedback control,” Proc. of the Annual IEEE Power Electronics Specialists
Conf. (PESC), pp. 1478—1484, 2007.
[Ichikawa2009] H. Ichikawa, T. Ichimura and S. Soyano, “IGBT modules for hybrid vehicle motor driving,” Fuji electric review, vol. 55, no. 2, pp. 46—
50, 2009.
[Kaiser1987] K. Kaiser, “Untersuchung der Verluste von Pulswechselrichterstrukturen mit Spannungszwischenkreis und Phasenstromregelung,”
Diss. Vienna Univ. of Tech., pp. 41—45, 1987.
[Kim1998] Y.-S. Kim and S.-K. Sul, “On-line estimation of IGBT junction temperature using on-state voltage drop,” Proc. of the 33rd IEEE
Industry Applications Society Annual Meeting (IAS), pp. 853—859, 1998.
[Kuhn2009] H. Kuhn and A. Mertens, “On-line junction temperature measurement of IGBTs based on temperature sensitive electrical
parameters,” Proc. of the 13th European Conf. on Power Electronics and applications (EPE), 2009.
[Motto2005] E. R. Motto and J. F. Donlon, “New compact IGBT modules with integrated current and temperature sensors,” Powerex technical
library, 2005.
[Musumeci2002] S. Musumeci, R. Pagano, A. Raciti, G. Belverde and A. Melito, “A new gate circuit performing fault protections of IGBTs during short
circuit transients,” Proc. of the 37th IEEE Industry Applications Society Annual Meeting (IAS), pp. 2614—2621, 2002.
[Olson2003] E. R. Olson and R. D. Lorenz, “Integrating giant magnetoresistive current and thermal sensors in power electronic modules,” Proc. of
the 18th Annual IEEE Applied Power Electronics Conf. and Exposition (APEC), pp. 773—777, 2003.
[Schmidt2009] R. Schmidt and U. Scheuermann, “Using the chip as a temperature sensor – the influence of steep lateral temperature gradients on
the Vce(T)-measurement,” Proc. of the 13th European Conf. on Power Electronics and applications (EPE), 2009.
[Shah2004] H. N. Shah, Y. Xiao, T. P. Chow, R. J. Gutmann, E. R. Olson, S.-H. Park, W.-K. Lee, J. J. Connors, T. M. Jahns and R. D. Lorenz, “Power
electronics modules for inverter applications using flip-chip on flex-circuit technology,” Proc. of the 39th IEEE Industry Applications
Society Annual Meeting (IAS), pp. 1526—1533, 2004.
[Slatter2011] R. Slatter, J. Schmitt and G. von Manteuffel, “Highly dynamic current sensors based on magnetoresistive (MR) technology,” Proc. of
the Power Conversion Intelligent Motion Conf. (PCIM Europe), pp. 616—620, 2011.
[Wang2009] Y. Wang, P. R. Palmer, A. T. Bryant, S. J. Finney, M. S. Abu-Khaizaran and G. Li, “An analysis of high-power IGBT switching under
cascade active voltage control,” IEEE Transactions on Industry Applications, vol. 45, no. 2, pp. 861—870, Mar. / Apr. 2009.
[Xiao2003] C. Xiao, L. Zhao, T. Asada, W. G. Odendaal and J. D. van Wyk, “An overview of integratable current sensor technologies,” Proc. of the
38th IEEE Industry Applications Society Annual Meeting (IAS), pp. 1251—1258, 2003.
Y. Lobsiger | 2011/06/30 @ ECPE Workshop MunichYou can also read
