Research Of Four-quadrant Rectifier Controlling Method

The main content of this research on the DVR of China Epri Science&technology Company’s Excellent Quality Department as background, because I am in the company engaged in design work on the DVR in the four-quadrant power unit hardware.With the continuously improve the performance of power semiconductor switching devices, PWM power electronic devices is becoming increasingly widespread. Because it has a series of advantages such as high-power operation, the stability of the DC voltage, the grid-side of the current sine, and can reach two-way transmission of energy, low harmonic pollution, in line with the future of green energy technology developments. PWM rectifier is the best choice of four-quadrant Power unit.The object of this paper is three-phase voltage source PWM rectifier, the majority of three-phase VSR control strategy is the use of double closed loop control strategy, that is, the inner current loop, outer voltage loop, current loop control has become the key of the system can be achieved.First, this paper describes the beginning of the basic working principle of the PWM rectifier, modulation and PWM rectifier topology.Then, detailed derivation the three-phase VSR’S three-phase stationary coordinate system, the two-phase stationary coordinate system, as well as the mathematical model of two-phase synchronous rotating coordinate system in the equilibrium conditions of the grid. This paper presents a combination of a space vector control and hysteresis current control method, and the current limit in a given hysteresis band. This is method of SVPWM current control based on indeterminate frequency hysteresis.Second, a detailed description of the dual closed-loop control strategy. Conduct modeling and simulation to compare two current control mode by the SIMULINK of MATLAB. The SVPWM current control based on indeterminate frequency hysteresis is better than the SVPWM current control.Third, hardware and software design on the four-quadrant power unit. It include control circuit, the detection circuit, protection circuit and power circuit and so on. And describe some of the circuits detailed. The software part describe the main program and interrupt subroutine simply.At the end of the paper, the design of the four-quadrant power unit meet to the experimental requirements expected.