Patent ID: 7170767

Claim:
A power conversion system comprising: a power transformer having at least one primary winding circuit and at least one secondary winding circuit, the primary winding circuit being electrically connectable to an AC power source; at least one power cell, each of the at least one power cell having a power cell input connected to a respective one of the at least one secondary winding circuit, a single phase output connectable to a load, a power switching arrangement including at least one power switch connected to the power cell input and a DC bus, a switch controller connected to the power switching arrangement and the power cell input, a PWM output stage having a plurality of PWM switches connected to the DC bus and the single phase output, and a local modulation controller connected to the PWM output stage, wherein the switch controller is adapted for monitoring and controlling a DC bus voltage according to a predetermined control methodology in both a motoring mode in which power from the AC power source is supplied to the load by the at least one power cell and a regeneration mode in which power from the load is supplied to the AC power source by the at least one power cell; and wherein the switch controller and the local modulation controller of each of the at least one power cell are connectable to a master controller that is connectable to the load to monitor power flow thereto.