三相抛物线PWM电流控制解耦方法(方法II)

Three-phase Parabolic PWM Current Control Decoupling Method(Method II)

抛物线脉宽调制(pulse width modulation,PWM)电流控制方法可直接用于单相或三相四线电压型变换器,具有良好的动、静态电流控制性能,并能保持开关频率基本恒定。但三相三线系统中,由于三相电流之间存在耦合关系,直接采用该电流控制方法,其控制性能会有所下降。通过线性变换,将三相三线变换器输出电流变换成虚构的两相电流,提出一种三相抛物线PWM电流控制解耦方法。该方法采用固定某一相开关状态,用两个单相抛物线PWM电流控制器产生另外两相开关信号,通过控制两相虚拟电流跟踪其参考电流,间接实现三相三线变换器实际电流的高精度快速跟踪控制。仿真和实验结果验证了该解耦控制方法的可行性和有效性。

The parabolic pulse width modulation（PWM） current control technique could be used in single-phase or three-phase four-wire voltage source converters（VSC） with a good dynamic and static characteristics as well as an almost constant switching frequency.However,when the parabolic PWM current controller（PCC） is used directly in three-phase three-wire VSC,the control performance will be deteriorated due to the mutual coupling of three-phase currents.In this paper,a three-phase PCC decoupling scheme was proposed by converting the three-phase three-wire VSC currents into virtual two-phase currents using linear transformation.With this scheme,one of the three phase PWM switching signals is fixed and the other two are generated by two independent PCCs to control the virtual two-phase currents tracking accurately their reference currents,and to control indirectly the actual currents of the three-phase three-wire VSC with high-performance.Both simulation and experimental results verify validity and correctness of the proposed three-phase PCC decoupling scheme.