Single-phase high power factor hybrid rectifier suitable for high-power applications

The study presents the development and the experimental analysis of a new single-phase hybrid rectifier with high power factor (HPF) and low harmonic distortion of current (THD_I), suitable for high-power application. The proposed structure is composed by an ordinary single-phase diode rectifier with parallel connection of a switched converter. It is demonstrated that the switched converter is capable of composing the input line current waveform assuring HPF and low THD_I, however, the power rating of the switched converter is lesser than 50% of the total output power, assuring robustness and reliability for the proposed hybrid rectifier. A prototype rated at 10%kW was developed and analysed in the laboratory, using low-cost analogue control technique. A pulse-width modulation (PWM) control strategy was implemented imposing quasi-sinusoidal input line current waveform and limiting the switched converter power contribution. It was found that the input line current harmonic spectrum is in accordance with the harmonic limits imposed by IEC61000-3-4. The principle of operation, the mathematical analysis and experimental results from a 10%kW prototype are also presented in this paper.