Research On Model-Based Predictive Direct Power Control For PWM Rectifier

With the development of power electronic technology, people also have a higher requirement to the power quality. The harmonic in power system is mainly from the power electronic equipment. With the use of these devices, the harmonic pollution is becoming more seriously, so improving the power quality has been widely concerned. Compared with other rectification devices, the PWM rectifier is widely studied by people.For the three-phase voltage source PWM rectifier, a proper control strategy can realize unity power factor. For traditional direct power control, its switching frequency is not fixed and it depends on the precision and sampling frequency of the sensor transformation.This paper proposes an improved direct power control(DPC) for the PWM rectifier by using model predictive control(MPC). This method is based on the principle of minimizing power error to choose the best vector. This control system designs the control delay compensation scheme, which is used to eliminate the power error produced by the control delay. Results show that this strategy not only achieves the sine current and the unity power factor, but also obtains a better steady performance and a faster dynamic response. This strategy achieves the fixed switching frequency and simplifies the design parameters of the rectifier system.