A Method to Determine Minimum DC-Link Capacitance in PWM Rectifier-Inverter Systems

Abstract

A method to determine minimum DC-link capacitance in PWM rectifier-inverter systems is proposed. First, a method to calculate the required DC-link capacitance at the steady state is investigated. Next, a method to calculate the DC-link voltage variation of PWM rectifier-inverter systems at a stepwise change in the output power is proposed. The results of the calculation are confirmed by experimental investigation. In addition, when the capacitance of the DC-link is reduced, the parameters that have a significant influence on the DC-link voltage variation are extracted. Then, based on the proposed calculation method for the DC link voltage variation and the constrained conditions determined by the parameters of the PWM rectifier, a calculation method for the minimum required DC-link capacitance at a stepwise change in output power is proposed.