This document discusses a parallel inverter circuit. It contains two SCRs that act as the main load carrying components. Diodes allow reactive power from the load to be fed back to the DC supply. When SCR1 conducts, the load voltage is positive and equal to the input voltage. When SCR1 turns off, the energy stored in the capacitor is fed back to the load through the transformer. This reverses the load voltage polarity. The parallel inverter has advantages over series and bridge inverters in that the load voltage is not dependent on the load, only two SCRs are needed, and commutation components do not carry the full load current.

1. Name :- Smit Shah -140410109096
T.Y Electrical 2 Sem 6
Subject:-Power Electronics 2
Topic :-Parallel Inverter
1

2. • The Inverter mainly classification based on the
configuration.
1. Series Inverter
2. Parallel Inverter or Push pull Inverter
3. Bridge Inverter
2

3. Circuit Diagram
3

4. Working Operation
• SCRs 1 &2 are the main load carrying SCR.
• The commutating components are L&C.
• Diodes 1& 2 permit load reactive power to be fed back to the
DC supply.
• These are called the feedback diodes.
• When sCR1 is conducting supply voltage Edc will appear
across the left half of
• the transformer primary winding OA.
• Terminal O is positive with reference to A thus, capacitor
• C will get charged to twice the input voltage.
• The load voltage will be positive and of magnitude Edc.
4

5. Working Operation
• At the end of the half period, SCR2 is fired.
• Capacitor C will immediately apply a reverse voltage of 2Edc
across SCR 1 and turns it off.
• When SCR 1 is turned off the capacitor will discharge through
SCR2, inductor L, Diode D1 and a portion of the transformer
winding LA.
• Thus the energy stored in the capacitance will be fed back to
the load through the transformer
• coupling of windings LA and PQ.
• During this period, the potential of point L will be fixed by the
• DC input supply and voltage will still be positive.
5

6. Working Operation
• The load current which earlier was flowing
• through SCR1 will flow through OL and diode D1 to the
negative input terminal.
• The current through the inductor L will now flow through D2,
M, B & S2 .
• The trapped energy in L will be fedback to the load. Since the
point M is now connected to the negative supply terminal, the
load voltage polarity will be reversed.
• Also the capacitor will be charged in the opposite direction.
6

7. Wave Form
7

8. Advantage of parallel Inverter
• The load voltage waveform is not depend on
load , as it does in series inverter.
• Only 2 scr are required as compared to at least
four in brige inverter configuration.
• It uses the simple class c commutation.
• It is simple & economical circuit.
• Commutation components do not have to
carry the entire load current.
8

9. 9