The Research Of Energy Feedback System Based On Three-phase PWM Rectifier

With the advantages of energy-saving and excellent motor control performance,general inverter is widely used in AC speed control system.When motor runs during regenerative braking,the regenerative energy is fed back from motor to the filtering capacitance which installed in the DC side of general inverter and will generate pump voltage.The traditional energy-consuming braking can no longer meet the needs of the development of times.However,using energy feedback unit to feed regenerative energy back to grid is the most cost-effective way.In this paper,an energy feedback control system is designed based on three-phase voltage-type PWM rectifier.Firstly,PWM rectifier four-quadrant operation mode is analyzed.Furthermore,the main circuit structure of energy feedback unit is introduced.According to mathematical model,the current control strategy is established.In order to solve the current circulation problem caused by parallel connection of energy feedback unit and the rectifier of inverter,the cause of current circulation is analyzed by equivalent circuit.A novel dual-carried wave SVPWM modulation method without zero vector is proposed.The rationality of the system control strategy is verified by simulation.Finally,a 380V/33kW energy feedback unit prototype was developed based on the theoretical analysis and simulation.In the hardware design part of the system,the main circuit and control circuit are designed.In the software design part,the algorithm of energy feedback unit is designed based on a RX63T microcomputer of Renesas.Based on the experimental platform of energy feedback system,some experiment of prototype has been done,the experimental waveforms and analysis of the results demonstarte that the system can feed regenerative energy back to grid effiectively.With the current circulation suppression algorithm,the system can achieve the desired function and improve efficiency.