A power supply generates alternating current and direct current from a constant-voltage source. A multi-phase pulse width modulation voltage source inverter is connected across the source to output multi-phase alternating current. At least one waveform generator is bridged in parallel with the inverter, with each waveform generator outputting zero-sequence waveform current compensated to maintain the multi-phase current within a predetermined tolerance from a desired set point. A rectifier receives the waveform current and generates direct current.