Performance characteristics of the combined zero-voltage switching inverter with the auxiliary input-current controller

The combined zero-voltage switching inverter with a single main power switch has been proposed as an electronic ballast for fluorescent lamps, in which the zero-voltage switching active filter and inverter are combined, and a main power switch in the active filter is used commonly as that in the inverter. This combined inverter has the superior advantages of simple circuit configuration, high power efficiency, high power factor, low distortion factor and so forth. However, the power factor and distortion factor of this combined inverter deteriorate when the AC input voltage or load vary. This paper presents a new control circuit to improve the performance characteristics such as the power factor, distortion factor of the input current, the crest factor of the output voltage, the voltage stress of the main power switch and so forth even when the AC input voltage or load vary.