Dynamic Harmonic Analysis of Power Router with Common High-frequency AC Bus Based on Phase Shift Control

Abstract

With the increase of users' DC power consumption and loads including DC links, the DC distribution network has become a better solution to solve the DC problem. As an intermediate device for AC and DC grid connection, the power router has functions such as controlling power flow and transmitting real-time information. However, the application of power electronic devices also introduces high-frequency and wide-frequency uncertain harmonic currents. This article mainly analyzes the dynamic influence of different operating conditions of the multi-port power router into the power grid on the current harmonics on the AC side of the power grid. The main task is to analyze the specific source and generation mechanism of harmonics, and propose an optimization method for phase-shifting control to suppress harmonics. First, the current research status of power routers is introduced, and the topology of routers in different application scenarios is given. Then, based on the power router with common high-frequency AC bus topology, a phase-shifting control strategy is proposed. The phase-shifting control strategy not only fulfills the frequency requirements of the high-frequency bus, but also removes the voltage limitation of the DC port, and has advantages over traditional PWM control in suppressing the harmonics of the AC side current. Finally, in the design process of high-voltage side rectification, the DC side voltage is set as the outer loop control, and the inner loop controls the power flow by parker transform of the AC power decomposition, and the AC voltage comparison link is added before the output control signal link to ensure modulation The signal is stable. In the simulation verification, this paper analyzes the suppression of harmonics by different control strategies, the dynamic AC side harmonics under different load changes, and the real-time changes of current harmonics when multi-ports are put into operation. The simulation results verify that the phase-shifting control can suppress harmonics better than traditional PWM control. The heavier load has a significant inhibitory effect on inter-harmonics, and the single resistive load port can be put into operation to reduce the total harmonic content of the system.