A Simple Control Method of Output Voltage for Three-Phase Multilevel Inverter Considering the DC Voltage Fluctuation

Multilevel inverter circuit generates the stair-like voltage without using transformer and interphase reactor, and it is the circuit which realizes reduction in the harmonics and enlargement of the capacity. In addition, the application of the PWM control improves the waveform, and it reduces the switching component to the conventional half, and the filter capacity is reduced.In this paper, improvement on voltage utilization factor and feed-back control of output voltage are applied to multilevel inverter circuit. For the DC power supply with the intense fluctuation, it is necessary to construct inverter circuit which can supply stabilized AC voltage. One-chip microcomputer with various functions is used for the control equipment of this circuit, and miniaturization and cost reduction of the control equipment are realized. Here, control principle and experimental result of this equipment are mainly reported.