Paper
This paper proposes a novel control strategy of a PWM converter with no power source voltage sensors. The strategy has two features to improve a total power factor including harmonic components without detecting the voltages. One is an estimation technique of the power source voltages, which can estimate instantaneous values of the voltages by evaluating instantaneous active and reactive power according to every switching mode of the converter. The other is a direct instantaneous power control technique, which can directly control the instantaneous active and reactive power by using switching modes as manipulated values for the converter. A DSP based experimental system was developed, and experimental tests were conducted. The control period of the system was only 15 /spl mu/s. It was confirmed that the maximum total power factor was more than 99%, and the maximum efficiency was 96.2%. The results have proven excellent performance of the proposed system.