Optimal Control of DC Capacitor Voltage for Cascaded Multilevel Converter

Cascaded H-bridge (CHB) multilevel converters have been widely used in industrial applications due to the low voltage stress, as well as high output power quality. Typically, the dc side of each module of cascaded converter requires a bulky capacitance, which increases the cost and size of the hardware system, and reduces the reliability. In order to solve the problem, aiming at reducing the dc capacitance, the mathematical model of the dc capacitance voltage of cascaded H-bridge multilevel is established. And then, a new optimal control system is proposed for dc capacitor voltage based on fixed integral filter algorithm. The test results verify the effectiveness of the proposed solution.