A Sensorless Technique to Improve the Third Harmonic Content in Single-phase DCM Boost Rectifier

This paper approaches a novel control strategy for boost rectifiers in discontinuous-conduction mode (DCM) to improve the power factor. Conventional DCM boost rectifier operates using a single output-voltage control loop, an excellent advantage for low-power applications. This strategy is simple, easier to be implemented and low cost. However, as drawback, it presents a high third harmonic component in the input current, resulting in a high total harmonic distortion (THD) and decreasing the rectifier’s power factor. Several techniques have been proposed in the literature to improve this drawback, all requiring either a current or input voltage sensor to improve the power factor correction (PFC). This paper achieves the PFC through the inherent output voltage-ripple of single-phase rectifiers without adding sensors. Experimental results verify a reduction in THD from 30% to under 5% over a wide range.