Monday, January 1, 2024

How to test IGBT Module with multimeter

 Test    IGBT   Module   with   multimeter

We  can  check  IGBT module condition :  good or bad with  analog  multimeter.  It is a basic testing with the most common tester.   Besides checking good or bad condition ,  we   check  to compare the measured  parameter  of   IGBT  from  different   supplier  as    maintenance  experience sometime we found IGBT is a  good condition when checking with multimeter  ,  but  when comparing  the measured  parameter  it has  some difference in detail.  Note   IGBT  module is a  power electronic devices  which is working at high current and high voltage ,  we  check  it  with a   multimeter that  is  a  low voltage testing ( analog multimeter 3VDC and 9VDC from Ohm range and  digital multimeter around  2.7V) sometime it found that it is a good IGBT if checking it with multimeter but  it fail when working  at high voltage and current.   However , checking it  with   multimeter  is  still  useful  and  necessary for repairing circuit.


How to to test  IGBT  Module  with  multimeter


How to to test  IGBT  Module  with  multimeter

                                    Internal    circuit   diagram   of    example   IGBT


Look  at  the  body of IGBT there is  terminal Gate ( G) , Collector ( C ) and Emitter ( E). Some model there is  one IGBT inside the module and some model has  2 IGBT inside the module.

Test    IGBT    Part   2

How  to  check  electronic  device

Choose   topics   below   to   read.




Step to  test  IGBT module with analog  Multimeter.

1.  Discharge  IGBT  by  shorting  3  terminal together ( G-C-E short).   The test IGBT must remove from circuit and there is no power present while checking.

2.  After discharging ,  do not touch any  metal terminal   and   hold at insulated case  if  need.


Test   IGBT
                                Discharge IGBT by shorting  3 terminal together


3.  Checking diode No. 1 at C1-E1 terminal  and  Diode No.2  at  C2-E2 terminal.  Set  range switch to  Rx1.  Good diode , the pointer will point at low resistance when forward biasing and the pointer will point at  ∞ Infinity scale when reverse biasing.   Shorted diode the pointer will point at  O Ohm and open diode   the  pointer  will  point  at   ∞ Infinity scale  2 time.


testing electronic components with multimeter
                    Forward bias to diode ,  the pointer will point  at  low resistance



Test   IGBT
                 Reverse  bias to diode ,  the pointer will point  at  ∞ Infinity scale  2 time.


4. Checking Gate biasing  to  ON  and  OFF  the   IGBT.  Set the range switch to  Rx10K  as this range of  multimeter supply  9VDC from  the  test lead to provide  basic  bias  IGBT.  Good IGBT can bias to ON and OFF.  Bad  IGBT can not bias (fail) to ON and OFF.


Test   IGBT  with multimeter
        Connect the test lead with IGBT ,  terminal  C1  E1 and G1  as photo below.



test  IGBT  Module  with  multimeter

   Trig   G1  to turn on   the IGBT , connect the test lead with   terminal  C1  E1 and  G1  



test   IGBT  Module  with  multimeter
       Remove  trig voltage from G1 , the IGBT still let current flow and the pointer still   point at the same scale as   time  when  connecting voltage to  trig  G1.


test  IGBT  Module  with  multimeter
 Turn  OFF  IGBT  by  short  G1 to  E1 terminal , the pointer move backward  to  ∞  scale 


5.  Repeat process  step 4 to check  Gate biasing  to  ON  and  OFF   IGBT No.2  (  C2 , E2 , G2)


Note  this  is  a  basic and  low  voltage  testing.  It tend to be good condition  when IGBT working at high voltage at specific circuit  , but sometime we found  it fail  at high voltage test.  You need to test and compare measured  Ohm  value  of  IGBT    that  from difference supplier.