Abstract: A control and regulation system for use with a harmonic neutralization frequency changer system. In the generalized frequency changer system, a direct converter frequency changer is used to convert bulk power, but unwanted harmonics are introduced. Input and output power distortion is monitored by a control system, and groups of high performance inverters inject shunt/series harmonic currents/voltages into a specially designed transformer to neutralize the power distortion to a specific acceptable level. Two control strategies are used including one that is based on discrete narrow band harmonic regulation and another that is based on wide band harmonic control. Each of these control strategies can be used at the input and/or output of the frequency changer and can be injected using shunt-current and series-voltage schemes.

Abstract: A power converter that produces variable frequency multiphase AC power from fixed or variable frequency AC power. The converter can be used to drive an AC motor for propulsion applications or other motors and loads that require variable frequency AC power. The power converter system is based on a combination of several power conversion technologies used in a power circuit topology and a regulator control system that allows for higher electrical efficiency, higher power density and lower power distortion to be achieved than is possible from any of the individual technologies. Specifically, the input and output power distortion of a frequency changer is monitored, and a group of high performance inverters are used to inject harmonic currents into a specially designed transformer to neutralize the power distortion to a specified acceptable level. By this neutralization, the power density of a solid-state electric power converter is increased (e.g., by a factor of 5-6) and power quality distortion is reduced (e.