The Research On Four-quadrant Converter Of Motor Driving Base On Energy Or Power Control

With the development of the power electronics technology and the modern control theory, four-quadrant converter was widely used in the industry and the new-energy field, like the back-to-back wind power systems, the HVDC systems, the four-quadrant converter for motor driving.Motor-driven four-quadrant converter control system was made up of the front-end PWM rectifier and the back-end motor controller, and the supporting capacitor connected the two parts. Compared to the motor controller powered by the non-controlled rectifier, four-quadrant converter had many advantages, such as the two-way flow of energy, the power factor control, the less harmonic component, the controllable DC voltage. The research on the motor-driven four-quadrant converter can be divided into two parts:the PWM rectifier control system and the PMSM control system.Firstly, the physical and mathematical models for the surface mounted permanent magnet synchronous motor were analyzed in the paper. At the same time, three control strategies for the PMSM, the speed measurement and the starting method of the motor were described. The mathematical model of the PWM rectifier was also analyzed, and the paper mainly said the vector control strategy based on grid voltage oriented for the PWM rectifier. On the basis of the above analysis, the similarity of the PMSM control system and the PWM rectifier could be gotten.Secondly, the new control strategy, the power/energy control, was proposed in this paper, and was applied successfully in the PMSM control system and the PWM rectifier. By the two comparative experiments, one is the vector control strategy with the outer loop of the energy storage of the motor rotor to the vector control strategy based on the rotor field oriented in the PMSM control system, the other is the control with the feedback the DC capacitor discharging energy and the feedforward of the load power to the vector control strategy based on grid voltage oriented in the PWM Rectifier, the new control strategy is validated.At last this paper combined the two control strategies, and applied them to the motor-driven four-quadrant converter. The effectiveness of energy/power control was verified by the further experiments.In this paper, some common problems of the control for the inverter were studied:(1)The influence on the fundamental and harmonic output voltage of the inverter by the dead time was analyzed, and the result of the simulation experiment verified the conclusions. (2) The similarity between the SPWM modulation and the SVPWM modulation wad concluded. And the method by injecting common-mode voltages into the SPWM modulation has an equivalent affection on the SVPWM modulation strategy.