| 摘要 |
When in an operation mode in which an alternating current voltage Vout is output using a positive voltage V1 of a direct current power source 1 input via a switching element Q1, a negative voltage V2 of the direct current power source 1 input via a switching element Q2, and a zero voltage Vz input via a bidirectional switch element BS1 or an alternating current voltage Vs input via a bidirectional switch element BS2, in the period in which the polarity of the output voltage Vout and the polarity of an output current Iout are the same, a control signal of an element to be caused to perform an on/off operation is generated by being pulse-width modulated using a carrier signal S with a first frequency, and in the period in which the polarity of the output voltage Vout and the polarity of the output current Iout are different, a control signal of an element to be caused to perform an on/off operation is generated by being pulse-width modulated using a carrier signal with a second frequency lower than the first frequency. |
