JIA Yu-hong，HE Chao，CHEN Guo-zhu
（College of Electrical Engineering，Zhejiang University，Hangzhou 310027，China）
Abstract：In order to solve the troublesome problem that traditional converter devices need to inspect the three-phase sequence of theelectricity grid before they connect to it，the phase sequence adaptive control method was applied to the control of the converter. If phasesequence is not correct when a device is connected to the electricity grid，the normal work of it will be influenced，considering theprerequisite of safe and reliable work of inverters is accurately acquiring the phase information. After the analysis of the fundamentalprinciple of three-phase digital phase-locked loop，the relationship between phase sequence and synchronous rotation transformation was
obtained，on the basis of summarizing the results of synchronous rotation transformation when the phase sequence was positive andnegative respectively. Then the detection method of three-phase sequence was put forward，and the phase sequence adaptive controlalgorithm was designed. By making use ofDSPTMS320F2812 programthephasesequenceadaptivecontrolstrategyoftheinverterwasobtained.SimulationresultsofMatlab/Simulink prove that the phase sequence is correct and the system runs stably. Thestrategy wasapplied to a small wind power back-to-back converter. The experimental results are accordant with that of simulation. They show that the
proposed method is simple and feasible，economic and convenient，which has great value in engineering application.
Key words：grid-connected inverter；adaptive three-phase sequence；phase-locked loop；synchronous rotation transformation