Power Quality in Class-D High-Frequency Power Inverter: Input and Resonant Tank Distortion Power, Total Harmonic Distortion, and Power Factor

This paper presents a power quality evaluation of the Class-D high-frequency power amplifier/inverter. The real, reactive, complex, apparent, distortion, and non-active powers at the input of the resonant circuit are derived and illustrated as functions of frequency. Also, the total harmonic distortion and power factor are determined. Similar analysis of the power quality at the dc input of the amplifier is given. Experimental results are given to verify the theory. It is shown that the input current of the Class-D inverter contains a significant ac component that does not contribute to the real dc input power, resulting in high distortion power, high total harmonic distortion, and poor power factor. The Class-D inverter was designed, built and tested to verify the theory.