Power Electronics Lab Experiments

To study Bridge inverter using IGBT. in Power Electronics Lab

Nov 27 2023

Aim

To study Bridge inverter using IGBT.

Apparatus Required:

S.No.	Apparatus/Software Used	Specification	Range/Rating	Quantity
1
2
3
4
5

Theory & Formulae Used:

Inverter is a unit to change DC supply to AC. There are several methods to achieve the same. Selection is depending upon our required AC data and DC availability. One question arrives that oscillator is also used for the same purpose. What is the difference between Oscillator and inverter? The oscillator is used to generate few milli watts and KH Hz AC. The circuit efficiency is non considerable factor and frequency accuracy is most important. But by inverter AC generated in several watts and KHz AC. The circuit efficiency is inconsiderable factor and frequency accuracy is most important. But by inverter AC generated in several watts or KWs at 50 Hz or nearby frequency. Here efficiency is most considerable factor. The bridge inverter has higher efficiency to generate AC wave. Generating frequency can vary by the potentiometer. Generated wave can be observed at CRO. The circuit is operated at 110 V DC. At short circuit condition or protective resistance 200 W lamp is given. The circuit along with power supply is capable to tolerate the short circuiting by IGBT of two one or two minute along with protective resistance.

Gate Frequency Generation: The gate frequency generation circuit is given in fig. ‘1’. To operate gate wave circuit +5 V DC is developed through diode D10, D11, D 12, D 13 , C 7, C8 and IC7. IC1 is astable multi-vibrator VR1 to control its frequency. It will give the output from pin no. 3 and fed to IC2 that is JK flip flop and its output will come through pin No. 3 and fed to IC2 that is JK flip flop and its output will come through pin no. 14 & pin no. 15. The frequency at 14 & 15 will half the astable multivibrator frequency. The output from pin no 15 will feed to pulse generator using IC3. Here IC3 is monostable mult ivibrator and gives the pulse to diode side of opto coupler IC4. The opto coupler is given for electrically isolation between gate frequency to Mosfet 1 & 2. The output of IC2 (JK FLIP FLOP) pin no. 14 is also fed to another monostable multivibrator using IC 5. The output of IC 5 from pin no. 3 is fed to opto coupler IC6.