DSP Microprocessor Based-On Power Factor Correction to Improve Power Quality of Converters Using Predictive Control

摘要

In this study, the predictive control approach is adapted to the current control strategy for the Bridgeless Power Factor Correction (PFC) converter. The control approach is developed to eliminate the input line current harmonics of the PFC converter without needing for the current sampling. In this approach, the zero crossing points of the input voltage are detected using DSP microprocessor. A sinusoidal signal is generated based on the detected points and used as a reference to control the converter switch to obtain unity power factor and lower input current Total Harmonic Distortion (THD). An adaptive digital FIR filter is designed and embedded into the control loop cancel the effects of noises and distortions on the output voltage. The feed forward technique is also used in the control algorithm by taking into account the maximum value of the input voltage. The implementation of feed forward and adaptive digital filter into the control algorithm improves the converter performance. The average current control (ACC) loop is used in the converter operating in continuous conduction mode (CCM). The converter used in simulation and experimental studies is a bridgeless power factor converter. The conduction losses of the switches of this converter are lower comparing to the similar PFC converters. The simulation and experimental results show that the proposed control strategy works well and the unity power factor operation can be achieved with a wide input voltage and load variation ranges. The results are compatible with IEC 61000-3-2 Current Harmonic Standard.