Passive Snubber Research Articles

Improvements to the passive lossless snubbers for power bridge legs

The paper considers three common snubber circuits used on gate turn-off thyristor and/or insulated gate bipolar transistor inverters. The three snubbers are passive lossless circuits for power bridge legs, and the improvements and modifications to these snubber circuits are presented. The comparative features and operation of the three improved energy recovery snubbers are discussed and supported by PSPICE simulations and experimental results.

Passive snubber energy recovery for a GTO thyristor inverter bridge leg

This paper presents a turn-on and turn-off passive energy recovery snubber circuit suitable for high-voltage high-power gate-turn-off thyristor inverter bridge configurations. The circuit recovers not only inductive turn-on and capacitive turn-off snubber energies, but also energies associated with freewheel diode reverse recovery. Energy is transferred back to the DC supply via a high-frequency transformer, that is fully reset. A method for reducing the transformer secondary diode voltage stress is presented. The performance of the circuit is supported by PSpice simulation, mathematical analysis, and practical results.

A novel lossless passive snubber for soft-switching boost-type converters

A novel lossless passive snubber is proposed for soft switching boost-type converters. The proposed snubber does not use any auxiliary switches, but uses two identical snubber capacitors which are charged in parallel at turn off of the main switch and discharged in series at turn on automatically, and the discharged energy is recovered effectively (more than 95% recovery) into the output capacitor. Thus, the snubber provides zero-voltage switching for the converter main switch, reducing both the turn-off losses and the electromagnetic interference (EMI) noise, which improves the converter performance. The experimental results of a 20 kHz 600 W DC-DC boost converter and a single-phase AC-DC boost rectifier with the new snubber are presented.

High power GTO thyristor chopper applications with passive snubber energy recovery

Single ended GTO thyristor chopper circuits find considerable use in high-power applications. The paper presents a single ended GTO chopper that achieves 100% recovery of all snubber energies. The limits of operation and minimum reset times are quantified and possible improvements to the basic circuit are presented. Circuit performance is supported by mathematical, time domain simulations and experimental results.

A novel unified passive lossless turn-on and turn-off snubber for highfrequency power converter applications

A novel unified passive lossless turn-on and turn-off snubber is proposed for a single-ended switch, where energy trapped in the snubber inductor and the capacitor is recovered into the DC rail and the load, without any active devices or resistors. The maximum over-shoot voltage on the switch is fixed, peak switch current is low, circuit reset is fast and the operational range of load current is wide, making this circuit suitable for use in high-frequency, power, single-ended GTO thyristor choppers and asymmetrical half-bridges. The recovery circuit may be operated as a soft-clamp. Design equations, simulations and practical results are given.

A novel passive dual energy recovery snubber for high power GTO converters

A novel passive dual energy recovery snubber circuit is presented where energy trapped in the snubber inductor and capacitor is recovered into the both DC rail and load, without any active devices or resistors. The maximum over-shoot voltage on the switch is fixed, peak switch current is low, circuit reset is fast and the operational range of load current is wide. This circuit is suitable for use in high frequency, single ended power gate turn-off (GTO) thyrister choppers. Main design equations, some simulations and practical results are included.