RF band power supply device and pulse width modulation control method

An RF band power supply device, comprising:

• a DC power source;
• a single-phase PWM inverter that comprises a single-phase full-bridge circuit formed by parallel-connecting two legs having switching elements on upper and lower arms between a positive end and a negative end of the DC power source, and convert a DC input supplied from the DC power source into an AC output by an ON/OFF operation of each switching element;
• and
• an inverter controller that compares a modulation wave with a carrier wave to generate a gate signal, and turns on and off the switching element by using the gate signal as a PWM pulse signal, so as to perform pulse width modulation (PWM) control on the single-phase PWM inverter,
• wherein the inverter controller comprises:
• a PWM control unit and a modulation wave/carrier wave generation unit for generating the gate signal,
• the modulation wave/carrier wave generation unit sets a modulation wave frequency fs of the modulation wave as a frequency in an RF band,
• wherein the modulation wave/carrier wave generation unit further comprises:
• a frequency synchronization unit that makes a carrier wave frequency fc of the carrier wave to be even-number N times higher than the modulation wave frequency fs;
• an odd function control unit that controls the modulation wave to be a sine wave of an odd function and the carrier wave to be a triangular wave of an odd function;
• and
• a phase synchronization unit that synchronizes a phase of the carrier wave with a phase of the modulation wave in each period of the modulation wave.