Abstract: An ac drive controller including a phase assembly for each phase of a polyphase supply to a motor, each phase assembly including an invertor module and a corresponding filter module. The electrical interconnections between each filter module and each invertor module occur through electrically conductive clips and corresponding bus bars to which the electronic switching devices in the invertor are also connected. The filter and invertor module interconnections are located as close as possible to the points where the electronic switching devices are connected to the buses to minimize stray reactances while allowing for simplified assembly and servicing of the controller.

Abstract: A hybrid inverter for a slip energy recovery system for a wound rotor motor employs six thyristors (for 3 phase operation) or equivalent devices. Three of these are operated continuously in the inversion mode, the other three being operated from zero degrees to 180 degrees. The result is that a characteristic that is identical to a semi-converter is obtained except in the inversion mode. The hybrid inverter produces zero quadrature current at the full speed of the wound rotor motor and, as desired, zero volts at maximum current and maximum volts at zero current.