基于空间矢量调制的非隔离型V2G系统共模电流抑制

发布时间：2018-02-27 00:04

本文关键词： 非隔离VG 共模电流中点电位平衡新型虚拟矢量法 H桥平衡电路协同控制　出处：《电力自动化设备》2017年09期 　论文类型：期刊论文

【摘要】：从系统高频共模等效模型入手,分析确定产生共模电流的激励源;改进传统抑制共模电压空间矢量调制(SVM)算法,优化三相三电平车网互动(V2G)开关状态转换次序,形成五段式去冗余SVM算法,有效抑制共模电压,但三相三电平V2G中点电位不平衡会对共模电压产生影响,限制了共模电流抑制效果。提出了从控制算法和拓扑改进2条途径分别实现中点电位平衡的控制方法。采用控制算法途径时,引入虚拟空间矢量调制(NTV2),剔除输出共模电压幅值较大的冗余小矢量,保证了共模电流抑制效果;重新定义虚拟小矢量和虚拟中矢量,在新型虚拟矢量空间下,提出分区域的混合调制策略,使其开关频率固定,通过控制开关周期内的平均中线电流为零实现中点电位平衡。采用拓扑改进途径时,调制方式仍采用上述五段式去冗余算法,以抑制共模电流;在直流母线处引入H桥平衡电路(或与之等效的单桥平衡电路),根据中点电位的偏移方向,选择平衡电路工作模式来调整直流母线电容所带电荷量,从而抑制中点电位的偏移,并可设置电压误差滞环,进一步增强了该方法的普适性和鲁棒性。仿真实验验证了理论分析和2套协同控制策略的正确性。
[Abstract]:Starting with the high frequency common-mode equivalent model of the system, the excitation source for generating common-mode current is analyzed and determined, and the conventional SVM algorithm for suppressing common-mode voltage space vector modulation (SVM) is improved to optimize the switching order of the switching state of the three-phase three-level network. A five-segment de-redundancy SVM algorithm is formed to suppress the common-mode voltage effectively, but the unbalanced neutral-point potential of three-phase three-level V2G will affect the common-mode voltage. The common mode current suppression effect is limited. A control method is proposed to realize the midpoint potential balance from the control algorithm and the topology improvement respectively. When the control algorithm is adopted, Virtual space vector modulation (VSM) is introduced to eliminate redundant small vectors with large output common-mode voltage amplitude, which ensures common mode current suppression effect, redefines virtual small vector and virtual middle vector, and redefines virtual vector in new virtual vector space. In this paper, a hybrid modulation strategy is proposed to stabilize the switching frequency, and to balance the midpoint potential by controlling the average midline current at zero in the switching cycle. When the topology improvement approach is adopted, the above-mentioned five-segment de-redundancy algorithm is still used in the modulation mode. In order to restrain common-mode current, H bridge balance circuit (or equivalent single bridge balance circuit) is introduced at DC bus. According to the offset direction of midpoint potential, the working mode of balancing circuit is selected to adjust the charge quantity of DC bus capacitance. Thus the offset of the midpoint potential can be suppressed and the hysteresis loop of voltage error can be set, which further enhances the universality and robustness of the method. The simulation results verify the correctness of the theoretical analysis and two sets of cooperative control strategies.
【作者单位】：华北电力大学新能源电力系统国家重点实验室;
【基金】：河北省自然科学基金资助项目(E2014502109) 中央高校基本科研业务费专项资金资助项目(2014ZD30)~~
【分类号】：TM464;TM73

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