Power Control and Sensing Method of kW Range Class E Power Amplifier

Dielectric heating systems uses high power circuit operating at high frequency. To apply the dielectric heating to the consumer electronics like dryer, the dielectric heating system needs a kW range power amplifier operating at above 1MHz of switching frequency. In high power circuit operating at high frequency, the power sensing circuit measuring voltage and current can measure inaccurate value because of high frequency noise. A method for control and measure accurate power value is proposed. The power sensing circuit can measure correct value because it operates at low power region. To avoid non-zero voltage switching (ZVS) at low voltage, the power circuit is turned on around the peak voltage. The 1kW class E power amplifier operating at 13.56MHz was tested to verify the proposed method.