级联H桥D-STATCOM双机并联系统PR重复控制策略研究

针对级联H桥型配电网静止同步补偿器(D-STATCOM)并联系统,文中分析双机载波相位差所导致的机间谐波环流问题,并根据单极倍频调制原理解释了载波移相产生谐波环流继而发生直流电压振荡的原因.为明确直流电压振荡对D-STATCOM所带来的负面影响,从双D-STATCOM的输出阻抗模型和直流侧电压的传递函数所反映的D-STATCOM机间的交互耦合特性入手,文中提出一种采用比例谐振(PR)重复控制抑制直流电压振荡的D-STATCOM电流内环控制策略,理论分析和系统仿真证明,该控制策略可使系统谐波含量减少,避免了谐波环流时D-STATCOM系统直流电压振荡导致直流电压失稳的情况.最后通过RT-LAB实时仿真平台验证了上述理论分析的正确性和控制策略的有效性.

Research on PR Repeat Control Strategy of Cascaded H-Bridge D-STATCOM Dual-Machine Parallel System

For the cascaded system of cascaded H-bridge distribution network static synchronous compensator(D-STATCOM),the inter-machine harmonic circulation problem caused by the phase difference of the two-carrier is analyzed,and the carrier phase shift generation is explained according to the principle of single-pole frequency doubling modulation.The cause of the DC voltage oscillations in the harmonic current loop.In order to clarify the negative impact of DC voltage oscillation on D-STATCOM,the interaction coupling between the D-STATCOM output impedance model and the DC-side voltage transfer function is proposed.The D-STATCOM current inner loop control strategy of proportional resonance(PR)repetitive control to suppress DC voltage oscillation,theoretical analysis and system simulation prove that the control strategy can reduce the harmonic content of the system and avoid the DC voltage oscillation of D-STATCOM system caused by harmonic circulation.The case of voltage instability.Finally,the correctness of the above theoretical analysis and the effectiveness of the control strategy are verified by RT-LAB real-time simulation platform.