Control Strategy Research Of APFC And Energy Feedback Of Motor Drive System

The development of economy is rapidly making progress in China, the and industrial 4.0 concept is popular in the world and gradually leads the trend of industrial development. Energy issue has become the focus of the economic development. According to the statistics, the electric energy consumed by the motor drive load accounts more than 70%. With the improvement of frequency conversion technology, it has brought the hope for industrial energy-saving and consumptioreducing. Because of the frequent braking, positive reverse and fast starting(such as lifting machine, fast elevator, automobile, air conditioning). The traditional general inverter can not have the function of energy feedback, and produces pump voltage rises. The traditional method is this way that connects the braking resistor in parallel with the DC link in order to consume braking energy, but this solution will produce heat and a waste of energy. So the APFC and energy feedback technology has important practical significance, also accords with the theme of the sustainable development strategy of the times.A series of studies about APFC and energy feedback control strategy are made. Rectifier circuit structure of inverter front-end is improved to realize the function of two-way flow of energy. Study double closed loop PI control strategy, establish the mathematical model, design the parameters of main circuit, design phase locked loop(PLL) and SVPWM. The simulation model of control circuit is established in MATLAB and double closed loop control of direct current control is realized.Because, double closed-loop PI control of direct current control has some problems, The input of the voltage loop was transformed to the difference of the voltage square and T/4 time-delay phase-locked loop was designed to solve the problems that cannot control system well and achieve accurate phase locking in the unbalanced grid in the traditional PLL.The direct power control strategy of the nonlinear control technology is proposed because of the complex nonlinearity of the motor drive system. On the basis of traditional direct power control, the fuzzy algorithm is introduced, in order to solve the contradiction between the hysteresis comparators and switching frequency of traditional direct power control, and improve the control effect.Finally, the simulation experiment of the proposed strategy is done, and results that the direct power control strategy is reliable.