Half Bridge Inverter

Half Bridge Inverter

Q. What is half bridge inverter?

Q. Single Phase Half Bridge Inverter Explained

Q. Half H-Bridge Inverter

Circuit Diagram of Half Bridge Inverter :

• Figure A shows the circuit diagram of a half bridge inverter.
• Only two thyristors S₁ and S₂, are used along with the feed-back diodes D₁ and D₂, connected across them. It is important to note that we can use any power device such as power transistor, power MOSFET of IGBT in place of the two SCR_S  S₁ and S₂ in this circuit.
• The DC power supply has been divided into two halves each one having a terminal voltage of V2 volts.
• The triggering and commutation circuits for SCRs have not been shown.

Figure A

Operation of Half Bridge Inverter with resistive load : 

• The thyristor S₁ is turned on at t = 0 for a time T₀/2, which makes the instantaneous voltage across the load V = V / 2. 
• If thyristor S₂  is turned on at instant T₀/2, by turning S₁ off then - V / 2 appears across the load. Thus a square wave is produced across the load.
•  A precaution must be taken while designing the control circuit so that both the thyristors are not turned on simultaneously, as it will short circuit the source and may damage the thyristors.

Waveforms of Half Bridge Inverter :

• Figure B shows the waveforms of output voltage and thyristor currents with a resistive load. The voltage across the thyristor when it is off is V and not V / 2.

Figure B