Explain with neat circuit diagram the operation of parallel inverter.

Ans:

Circuit diagram: 

Operation:

• Initially, SCR T1 is triggered and current flows through Edc-L-0 -T1 - Edc. As the no. of turns in OA is equal to no. of turns in OB and is equal to no. of turns in PQ, the secondary voltage will be Edc as shown above (Q +ve w.r.t. P)  

•  As the rate of change of load current remains constant, the secondary voltage also remains constant as shown below.  

•  Due to transformer action, capacitor is charged up to 2Edc with right plate +ve and left plate -ve .  

•  When the capacitor is fully charged up to 2Edc, SCR T2 is triggered and the capacitor potential is applied across SCR T1. Hence SCR T1 goes into OFF state due to voltage commutation. As SCR T2 is conducting now current starts flowing through Edc - L- O- B - T2 - Edc. Since the direction of current is reversed, the direction of load voltage is also reversed as shown below. Hence P is +ve w.r.t Q.  

•  Now the capacitor charges upto 2Edc with left plate +ve & right plate -ve. With this capacitor potential SCRT1 is triggered. As soon as SCR comes into conduction SCR T2 goes into off state due to voltage commutation an  

•  and the cycle repeats. 

 Waveforms: