IEC60747-9

This chapter first describes the important parts of the IEC 60747-9 standard with regards to switching times and energies. Afterwards it gives some notes and explains how PD1000A software adapts this standard or deviates from it. The standard is applicable for discrete (according to title) IGBTs.

Test setup

The test setup for both switching times and energies is a standard clamped inductive load double pulse test.

 

Measurement Procedure and Waveform

Measurement Procedure

The gate voltage level V_GG1 and V_GG2 and the supply voltage V_CC are set to the specified values. The minimum turn-on pulse duration must ensure a complete saturation of the IGBT. The collector current I_C, the gate emitter voltage V_GE and the collector emitter voltage V_CE are monitored simultaneously.

E_OFF is the integral of V_CE x I_C x dt. Integral time T_I starts from the 90 % fall point of V_GE and ends at the specified low I_C point, the 2 % point of I_C before turn-off. The turn-off power dissipation is the product of the switching frequency and the turn-off energy per pulse as determined by the integration.

Specified Conditions

• Case or ambient or virtual junction temperature of the IGBT and the diode
• Voltage of intermediate circuit V_CC
• Collector current I_C just before 1^st turn-off (I_CM)
• Gate voltage -V_GE before and +V_GE after turn-on
• Gate resistor R₁ (R_GON)
• Characteristics of freewheeling diode

Voltage and Current Levels:

• Some levels are not defined properly in the standard
• 0.9 V_GE and 0.1 V_GE is with reference to 0 V, not the negative gate voltage.
  • Example: gate voltages of 20 V/-5 V would lead to 10 %=2 V and 10 %=18 V

• 0.9 I_CM, 0.1 I_CM and 0.02 I_CM are with reference to 0 A.
• 0.02 V_CC should be 0.02 of supply voltage according to standard. We measure V_CE between pulses and use this as 100 % reference. 0 % reference is measured at the end of the first pulse while device is still fully turned on. This way 2 % is mostly able to be reached. Without this it is often not possible for high currents due to beginning of saturation etc.
  • Example: Test is measured at V_CC = 800 V. At the end of first pulse we measure V_CE = 10 V, between pulses we measure V_CE = 795 V. This is 0 % and 100 %. Because of this 0.02 V_CC is 25.7 V instead of 16 V or 15.9 V.

• The levels are measured on the original signals, except for 100 % of I_CE. To extract 100 %, the I_CE signal is low pass filtered with a frequency of 10 MHz.

Start and end times

• Currently software always searches first crossing of voltage/current levels searching from left to right. This can lead to smaller times or energies when there is a lot of ringing in the system etc.. Infineon suggested searching from the right for searching for e. g. the end of t_i
• The following formulas are used as start and end times of turn on/off:
  • start time = turn on/off time
  • end time = start + delay + rise/fall time