Utilization of the series resonant DC link as a DC motor drive

The use of a high-frequency series-resonant DC link power converter as a DC motor drive is described. This system generates a resonant current in a series link, and switching is performed at zero current instants, reducing switching losses to a minimum value. A pulse-density modulation (PDM) strategy, utilizing a current regulator loop and an external motor speed feedback loop, controls the resonant converter. A sinusoidal input fundamental current and nearly unity input power factor are observed in different load conditions. The overall characteristics of the system, including such variables as maximum power, input current, start up, and transient responses, are presented by digital simulation and verified on a prototype system.< >