Waveform distortion in a power-factor-corrected constant-voltage constant-current AC power supply using variable capacitance devices

New constant-voltage constant-current ac power supply is presented. Our original Variable Capacitance Device is utilized in the power stage as linear reactance device. This circuit theoretically makes no distortion of output voltage waveform and a high efficiency can be obtained. For output voltage/current control and input power-factor correction, two Variable Capacitance Devices were employed as linear capacitor. The unity input power factor can be obtained all over the constant-voltage region and the constant-current region. Input current becomes almost zero at no load and at short-circuit load.