Interleaved Four-Phase Buck-Based Current Source With Isolated Energy-Recovery Scheme for Electrical Discharge Machining

This paper presents the interleaved four-phase buck-based current source in continuous conduction mode with proposed isolated energy-recovery scheme for electrical discharge machining (EDM). EDM requires a pulse current with high slew rate in the output current of the current source. The interleaving technique allows the output slew rate of the buck-based current source to be improved due to the existence of the paralleled inductors at the start of discharge. The proposed isolated energy-recovery scheme provides a major path for the inductor to release its stored energy, thus avoiding high voltage stress in the output terminal when the gap reverts to the high-impedance state. The energy stored in the inductor is recycled to the input capacitor and can be reused for machining. The experimental results validate that the output current slew rate is high and that the energy is recovered when the gap is in the high-impedance state.