Research of Direct Power Control of PWM rectifier based on virtual flux

In PWM rectifier control strategy, Direct Power Control (DPC) has been used more and more widely in order to solve the problem of complex rotating coordinate transformation of Vector Control. Traditional DPC method with variable switching frequency is applied based on instantaneous power theory and switching table. This approach requires more voltage and current sensors to calculate active and reactive power, leading to low anti-jamming capability. And the use of bang-bang control results in large power fluctuation. For these problems, an improved DPC strategy with fixed switching frequency is proposed based on virtual flux and Space Voltage Modulation (SVM). This method simplifies the circuit structure by omitting the voltage sensors and obtains continuous control by SVM instead of switching table. A comprehensive theoretical analysis of two DPC methods above is given and the comparison of simulation results is presented in Matlab/simulink. The simulation results show that DPC based on virtual flux and SVM has better dynamic and static control performance.