Design of the controller and improvement of the dynamic performance for single-phase PWM rectifiers

The double loop control strategy with which proportional integral (PI) controller used in voltage loop and proportional-resonant controller used in current loop is analyzed by establishing mathematical model of the single-phase pulse width modulation (PWM) rectifier, and the design formula of voltage loop PI controller is given. The problem of proportional-resonant controller of current loop was system stability reduction due to the narrow bandwidth. The quasi-proportional resonant controller used increased the bandwidth, and reduced the sensitivity of the system to circuit parameters and grid frequency fluctuations. Second harmonic voltage in the output DC voltage limits the bandwidth of the voltage loop. Therefore, three ways of suppressing second harmonic voltage in voltage loop controller were compared and analyzed. A voltage outer loop controller which is parallel notch filter on the proportional integral filter controller was proposed. Its validity and feasibility are verified through simulation and experiment results. © 2020, Harbin University of Science and Technology Publication. All right reserved.