A medium voltage power supply with enhanced ignition characteristics for plasma torch in waste disposal system

This paper investigates a power supply of medium voltage with enhanced ignition characteristics for plasma torch in waste disposal system. Series resonant half-bridge topology is presented to be a suitable ignition circuitry. The ignition circuitry is integrated into the main power conversion system of a multi-phase staggered three-level dc-dc converter with a diode front-end rectifier. The plasma torch rated for 3MW, 2kA and having the physical size of 1m long is selected to be a high enthalpy source in waste disposal system. The steady-state and transient operations of plasma torch are simulated. Circuit simulation waveform shows that the ripple of arc current can be maintained within ±10% of its rated value under the existence of load disturbance. This power conversion configuration provides high enough ignition voltage around 30kV during ignition phase and high arc stability under the existence of arc disturbance noise resulting in a high-performance and reliable plasma torch system.