基于虚拟电压矢量的五相电压源逆变器空间矢量调制算法

Virtual Voltage Vectors Based Space Vector PWM Method for Five Phase Voltage Source Inverters

在多相电机驱动系统中,逆变器控制和调制算法引起的共模电压将会产生电磁干扰,从而影响系统正常工作、损坏电机定子绕组绝缘,降低电机使用寿命等;五相逆变器输出电流低次谐波将会导致定子铜耗增加,转矩脉动变大,影响电机控制性能。因此,为抑制输出电流中所含的低次谐波分量,并减小共模电压,提出一种基于虚拟电压矢量的五相电压源逆变器空间电压矢量脉宽调制算法(virtual voltage vector based space vector pulse width modulation,V3-SVPWM)。首先,根据伏秒平衡原理,选择相邻4个大矢量按照特定占空比合成有效虚拟电压矢量,选择2个方向相反的大矢量合成虚拟零矢量。然后,使用虚拟电压矢量合成参考电压,计算过程简单,便于数字实现。最后,将所提算法与最近2矢量SVPWM(near-two vectors based space vector pulse width modulation,NTV-SVPWM)和最近4矢量SVPWM(near-four vectors based space vector pulse width modulation,NFV-SVPWM)进行仿真和实验对比研究,验证所提算法的正确性和有效性。

In multiphase machine drive system,the common mode voltage(CMV)resulting from the control and modulation schemes will bring electromagnetic interference,which leads the system to work abnormally.The CMV will also destroy the stator isolation,reduce the machine service life.Besides,the low-order harmonics in the phase currents increases copper losses and torque ripple.As a result,the system performance is deteriorated.In order to suppress the low-order harmonic currents and reduce the CMV,a virtual voltage vectors based space vector pulse width modulation(V3-SVPWM)scheme for five-phase VSIs was proposed.Firstly,four adjacent large vectors were selected to synthesize active virtual voltage vectors with the redefined duty ratio,zero virtual voltage vectors were synthesized with two opposing large vectors,according to volt-second balance law.Then,the reference voltage was synthesized using the virtual voltage vectors.The process was simple and easy to realize on embedded controllers.Finally,a performance comparison of the proposed V3-SVPWM,near-two vectors SVPWM(NTV-SVPWM)and near-four vectors SVPWM(NFV-SVPWM)schemes has been presented on Matlab/Simulink and experimental platform.Simulation and experimental results have verified the feasibility and effectiveness of the proposed V3-SVPWM scheme.