# Single phase bridge inverter

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## Single phase bridge inverter

The function of inverter is convert DC to AC voltage.

• Two types of single phase bridge inverter
1. single phase half bridge inverter
2. single phase full bridge inverter

## Single phase half bridge inverter

##### Circuit Description :-
•  Two Thyristor S1 and S2 are used along with two feedback diode D1 and D2 respectively.
• Resistive load is connect between point A and B, as shown in fig:-
• Supply voltage is divided intp 2 parts, here two DC voltage source are used V/2 and V/2.
• Fig of the single phase half bridge inverter is given below:

### Working:

Mode 1 (0 to T/2):-

• During this mode switch S1 is ON and switch S2 is OFF From period 0 to T/2.
• Current flowing path during this mode is V/2-S1-B-R(Load resistor)-A-V/2.
• Hence the voltage across the load is positive V/2

Mode 2 (T/2 to T):-

• During this mode switch S1 is OFF and switch S2 is ON From period T/2 to T.
• Current flowing path during this mode is V/2-A-R(Load resistor)-B-S2-V/2.
• Hence the voltage across the load is negative V/2.

1. Load is resistive hence it does not store any charge therefore feedback diode D1 and D2 are not effective here.
2. The main drawback of half bridge inverter is that two DC voltage source are require. By using full bridge inverter we can overcome that drawback.

## Single phase Full bridge inverter

##### Circuit Description :-
• Four thyristor are used in full bridge inverter. Thyristor S1 and S2 are used along with two feedback diode D1 and D2 and thyristor S3 and S4 are used along with another two feedback diode D3 and D4 respectively.
• Fesistive load is connect between point A and B,as shown in fig:-
• DC voltage source is applied to circuit.
• Fig of the single phase full bridge inverter is given below:

Mode 1 (0 to T/2):-

• During this mode switch S1 and switch S2 are ON and switch S3 and switch S4 are  OFF From period 0 to T/2.
• Current flowing path during this mode is Vdc – S1- P -R(load reistor) – Q – S2 – Vdc.
• Voltage across the load resistor is   positive Vdc

Mode 2 (T/2 to T):-

• During this mode switch S3 and switch S4 are ON and switch S1 and switch S2 are OFF From period T/2 to T.
• Current flowing path during this mode is Vdc – S3 – Q – R(load reistor) – P – S4 – Vdc.
• Voltage across the load resistor is negative Vdc.
1. Load is resistive hence it does not store any charge. therefore, feedback diode D1, D2, D3 and D4 are not effective here.
###### WAVEFORM OF OUTPUT VOLTAGE THYRISTOR CURRENT WITH RESISTIVE LOAD ARE SHOWN IN FIG: 1. Jim
2. Radha adhikari