| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation of a harmonic by inhibiting the distortion of an output current, by selecting whether or not zero-voltage switching by a zero-voltage circuit is conducted in response to the pulse width of pulses for controlling the switching of an inverter circuit. SOLUTION: In an inverter, a selecting circuit 24 selecting whether or not the zero-voltage switching of an inverter circuit 2 by a zero-voltage circuit 3 is performed on the basis of pulse width detected by a pulse width detector 11 of pulses TPWM from a PWM timing generating circuit 6 and a reference pulse width Tsw is installed. Zero-voltage switching is conducted when the pulse width of PWM pulses TPWM exceeds a reference pulse width Tsw by controlling first and second switching circuit 12, 13, and zero-voltage switching is not executed when pulse width is narrowed and the pulse width of PWM pulses TPWM reaches reference pulses or less. Accordingly, since zero-voltage switching is not performed for a period when distortion is generated at an output voltage, the distortion of an output current can be improved, and the generation of a harmonic can be prevented. |
