Welcome to electrical and electronics engineering Q&A site...

Welcome to electrical and electronics engineering discussion website, Please login or register to continue.

Join our WhatsApp group

Subscribe To Our YouTube Channel

85 views
in Unit 1 by
Also, highlight the problem faced during parallel operation.

Amazon Shopping

Please log in or register to answer this question.

1 Answer

0 votes
by
 
Best answer

Parallel operation of IGBT:

Parallel operation of IGBT is done for obtaining high current rating. Paralleling of IGBT reduces conduction losses and thermal stress. IGBT combines the qualities of BJT and MOSFET. So, IGBT have both negative and positive temperature coefficient. Means for collector current up to about 70% of rated value IGBT shows negative temperature coefficient and after that IGBT shows positive temperature coefficient. For example, if IGBT is rated for 10A then for up to 7A the IGBT will show negative temperature coefficient and after that up to 10A IGBT will show positive temperature coefficient.

For successful parallel operation of IGBT

1.Each IGBT should have its own gate resistor.

2.The arrangement of the layout of the chips should be such that the current flow path should be symmetrical.

3.The IGBT should be thermally coupled by mounting them on the same heatsink.


image


Problem faced during parallel operation of IGBT:

  • IGBT have static and dynamic current sharing problem.
  • The static current sharing problem is related to magnitudes of individual collector current.
  • The dynamic current sharing problem is related to turning on and  turning off times
  • For better current sharing in parallel IGBT require gate-emitter threshold voltage and transconductance (g) which is the ratio of collector current (Ic) to gate voltage (VGE) to match.
  • The turning on and turning off time of IGBTs must be same.
  • High frequency may cause dynamic unbalance problem.
  • A drive circuit is needed for equal turn on and turn off time.
  • IGBTs must share losses equally otherwise IGBT may get failure due to thermal differences.

Amazon Shopping

Welcome to Q&A site for electrical and electronics engineering discussion for diploma, B.E./B.Tech, M.E./M.Tech, & PhD study.
If you have a new question please ask in English.
If you want to help this community answer these questions.

Categories

Most popular tags

power motor dc circuit transformer voltage current used system phase factor resistance load synchronous energy ac induction generator electric series frequency capacitor use speed between electrical meter line type mosfet control transmission difference magnetic plant high single instrument bjt source advantages function diode machine unit winding torque amplifier define supply thyristor motors arduino field shunt maximum relay armature problem electricity time parallel on transformers types coil diagram state flow value material three starting and direction theorem method emf operating digital microprocessor test instruments efficiency ratio loss measure operation connected low applications wave effect single-phase working losses different network wattmeter temperature measuring constant signal controlled breaker device full compare drive wire resistivity logic materials machines inductance switch flux disadvantages converter transistor gain protection scr angle force core measurement number free principle rc generators law negative bridge friction open pole conductor conservation steam iron loop resistors hysteresis short computer using lines secondary station battery rectifier inverter linear relays nuclear regulation circuits design analog work rotor electronics gate forces diesel damping rlc connection factors capacitors minimum insulation basic moving running reactance systems air fault range direct main stability quality starter igbt eddy ideal ammeter rl 3-phase plants arc induced thermal error fuzzy biasing dielectric pressure balanced superposition errors rotation characteristics feedback measured electronic start alternator off back curve over solar three-phase tariff locomotive peak bias zener capacitance commutator surge rating universal potentiometer permanent mechanical copper self transducer capacity electrons memory adc excitation inductive transfer explain fuse pure harmonics application inductor internal pmmc average reaction welding resonance traction breakers designed electromagnetic si generation brushes density switching shaded rate impedance distribution methods star oscillator reluctance semiconductor simplification algebra 8085 boolean weston dynamometer insulating strength installation permeability definition fuel heating earth units neutral rms rated engineering conductors coefficient controller usually reverse excited analysis change body components
...