| 摘要 |
PURPOSE:To enable to continuously switch the carrier frequency by dividing the pulses of a carrier pulse train into a plurality of pulses in response to a command voltage when the command voltage is smller than the set value. CONSTITUTION:A carrier signal fc'' is composed of a waveform of rectangular tridecagonal shape formed of 5 points of voltage V0, V2, voltage 0 and a waveform of a triangular shape of the point of the voltage V2 as a vertex and the other two point voltages being 0. Accordingly, as the command voltage Vref decreases from the voltage V0 to the voltage V2, the pulse width gradually decreases, and the pulse interval increases. When the voltage Vref becomes smaller than the voltage V2, the pulses in case of Vref=V2 is isolated into two pulses from the center of the pulse width. The pulse width of the both pulse decreases in response to the voltage Vref. Sincs the carrier pulse CP continuously varies in frequency, the carrier frequency can be switched without a shock. |
