基于对零轴矢量构造d,q坐标系的电流控制方法

The Current Control Method Based on Using Zero Axial Vector to Construct d,q Coordinate System

为解决三相不平衡系统中零序电流无法准确跟踪控制的问题,提出一种对零轴矢量构造新同步旋转d,q坐标系的电流控制方法。在d,q,0坐标系中,通过二阶广义积分器(SOGI)90°移相系统将零轴构造成一个静止虚拟坐标系,对该虚拟坐标系通过Park变换变为旋转面垂直于原d-q平面的新d,q旋转坐标系,使零轴上交流矢量在新d,q坐标系下变换为直流量,利用比例积分(PI)控制器实现无静差跟踪。仿真和实验结果表明,所提控制方法可实现对零序电流准确跟踪,同时对小范围频率偏差具有明显的自适应能力,解决了三相不平衡系统中零序电流补偿的技术难题。

In order to solve the problem of the zero sequence current can＇t be accurately tracked control in threephase unbalanced system,a current control method based on using zero axial vector to construct new d,q coordinate system is proposed.In d,q,0 coordinate system,by 90° phase shifting system of second order generalized integrator（SOGI） can structure zero shaft into a static virtual coordinate system, converting the virtual coordinate system into a new d,q coordinate system which rotating surface is perpendicular to the original d-q plane by Park transformation,making alternating crrent vector in zero axis converted to direct current value under new d,q coordinate,then using proportional integral（PI） controller to realize the astatic tracking.The results of simulation and experiment show that the proposed control method can achieve accurately tracking zero sequence current, which has obvious adaptive ability for a small range of frequency deviation at the same time, which has solved the technical problem of the compensation of zero sequence current in three-phase unbalanced system.