A feedback linearizing control scheme for a PWM converter-inverter having a very small DC-link capacitor

This paper addresses a control method of reducing the size of the DC-link capacitors of a converter-inverter system. The main idea is to utilize the inverter operation status in the current control of the converter. Specifically, the information on the load power is incorporated in synthesizing the converter current control input so that a proper DC voltage level is maintained. We describe the dynamics of load current and apply feedback linearization theory to obtain an input output linearized system. Theoretically, this control strategy is effective in regulating the DC voltage level, even though the DC-link capacitor is arbitrarily small and load varies abruptly. The superior performance is demonstrated through simulation and experiment. An experiment was performed with a 9-kW pulsewidth modulation converter-vector inverter system having a 75-μF DC-link capacitor