Patent ID: 6542390
Filing Date: 2003-04-01
Classification: H02M,H02P

Abstract:
A power conversion system for driving a load, the 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 the load, an SCR arrangement including a gate drive and at least one SCR connected to the power cell input and a DC bus, an SCR controller connected to the SCR 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 SCR arrangement and the SCR controller are configured for controlling a DC bus voltage, the PWM switches are configured for controlling power flow to the single phase output, and the local modulation controller is configured for controlling activation of the PWM power switches; and a master controller in communication with the SCR controller and the local modulation controller of each of the at least one power cell, the master controller being connectable to the load to monitor power flow thereto, wherein the SCR controller includes a DC bus voltage controller connected to the DC bus, the DC bus voltage controller including a summing junction configured for determining a voltage error between the DC bus voltage and a voltage reference, a DC bus voltage regulator in communication with the summing junction, and a firing angle controller in communication with the DC bus voltage regulator.