Research On LVRT Technology Of D-PMSG Based On SIMULINK-DSP Model

With the continuous development of wind power industry, the low voltage ride through (LVRT) problem of direct drive wind power generation (D-PMSG) has become more serious. D-PMSG has advantages of low speed, high power factor, high efficiency and flexible control of active and reactive power. It’s connected with the grid through back-to-back converter, so its LVRT capability is more outstanding than double fed type wind machine (DFIG).At present, the feasible method of D-PMSG LVRT problems is allocating power storage system in wind farm. The super capacitor,because of the merits of high power density, long cycle life, high charge discharge efficiency, good performance under high and low temperature, can effectively prolong the operation time of energy storage system and improve its economic performance and power output capability.This paper takes the D-PMSG as the research object, analyzes and summarizes the LVRT technology of D-PMSG. According to the working characteristics of super capacitor, design the super capacitor charging and discharging control strategy based on the bidirectional DC-DC circuit to realize the LVRT of D-PMSG.Combined with the concrete operation parameters of super capacitor and D-PMSG, build equipment modeling in SIMULINK environment, build a complete D-PMSG system.Based on Crowbar protection circuit, to realize the LVRT of D-PMSG with the energy storage super capacitor, and design a charge and discharge control strategy. In the bidirectional DC-DC circuit as the control system, using LLC half bridge resonant circuit to realize the electrical isolation. Modeling of the control circuit in SIMULINK and the simulation is conducted for different fault conditions.Improved on MATLAB-DSP integrated design technology, puts forward the SIMULINK-DSP integrated design technology, direct transform SIMULINK model to DSP code. Aiming at the problem of low efficiency of the generated code, and puts forward several measures for code optimization. Finish the optimization of super capacitor charging and discharging control system DSP chip code.Finally test the control device in laboratory environment, verify the effect of super capacitor to LVRT ability of D-PMSG.