New snubber circuit with passive energy recovery for power inverters

The paper proposes a new passive circuit for partial snubber-energy recovery in GTO thyristor high-power voltage-source inverters. The analysis and simulations show that the proposed bridge-leg snubber circuit can recover greater than sixty five per cent of the total snubber energy, as well as the freewheel diode reverse recovery energy. This energy is recovered back to the DC supply through a closely coupled transformer, without any active devices or associated control circuitry. This snubber circuit, being simple, is particularly suitable for use in GTO thyristor high-power inverters. Design equations, simulations and experimental results are given.