抄録
The introduction of a multiple PWM inverter to the power supply system for LSM drive is examined. The author are examining about the output harmonics of the inverter which is composed of a Half Bridge (HB) unit and Full Bridge (FB) ones.
The PWM inverter generates the lowest frequency harmonics of fc (Hz), which is the carrier wave frequency of HB unit. To improve the characteristics of the output harmonics, the author have proposed “the balanced carrier phase method”, which assignes balanced phase angles to the carrier waves of units with HB connection.
In this paper, the principle of the proposed method is described. Then the author derive the analytic expression of the output voltage, and examine quantitatively about the characteristics of output harmonics. Moreover, the author show that the new method shifts the lowest frequency of the harmonics to higher region and reduces whole quantity of harmonics in comparison with conventional method.
