Study Of Three-phase PWM Rectifier Control For Ship Electrical Propulsion Test System

Ship electric propulsion is the inevitable trend of ship-building industry. But the voltage source inverter which is applied in the ship electric propulsion system now exists problems: serious harmonic pollution and low power factor. In this paper, focused on those problems, a three-phase PWM rectifier system has been studied. And its control system has been designed and tested. The three-phase PWM rectifier system studied in this paper has been proved that it can effectively reduce harmonic pollution and improve power factor.In this paper, three-phase half-bridge voltage source PWM rectifier (VSR) is studied since this rectifier fits the ship electric propulsion test system's voltage level, has the right cost and simple structure. Firstly, the analysis of working principle of three-phase PWM rectifier system is given. The mathematical model of three-phase PWM VSR is established under a rotating coordinate system. Secondly, based on the analysis of existing switching dead-time, a new type of non-dead-time control method is discussed. Under the rotating coordinate system, a control method, named line-voltage-oriented dual-closed-loop voltage SVPWM method, is applied. And the SVPWM algorithm is studied. The three-phase PWM VSR test system is developed. On TMS320F2812, the digital control system circuit is designed, including the isolation sample conditioning circuit, IGBT drive circuit, fiber-optic isolation circuit, protection circuit, human-machine interface (LCD, keyboard). The software is programmed and the digital PI regulator and the SVPWM generator algorithms are implemented.Based on the simulation tools of MATLAB/SIMULINK, the desined three-phase PWM-VSR for ship electric propulsion test system is simulated. The results are shown that the designed system is correct and effective. The test results for three-phase PWM VSR system are shown that the designed system has the features of smaller harmonic current, high power factor and good system dynamic performance. So this system meets the design requirements.