统一电能质量调节器串联变流器多频级联无源控制研究

Study on Multi-frequency Cascade Passivity-based Control for the Series Converter of Unified Power Quality Conditioner

统一电能质量调节器的串联变流器数学模型是高阶模型,为了在频域中提高高阶控制系统的动静态性能,提出一种多频级联无源控制策略。首先,采用傅里叶变换技术对其交流数学模型进行频谱分解及多频直流建模,然后在被指定的频率模型上将系统降阶成级联的低阶模型;针对此级联低阶模型进行了一种新型无源控制器设计,理论分析表明所提的控制器不仅在频域上实现了对串联变流器的灵活控制,而且在无法获知控制对象精确模型时也实现了零稳态误差控制,有效克服了传统无源控制器控制性能依赖控制对象模型精度的缺点。最后,进行实验验证,实验结果表明所提的控制策略是可行的。

Mathematical model of the series converter ofunified power quality conditioner （UPQC） is a high-order model. In order to improve the dynamic and static performance of the high-order system in frequency domain, a control scheme called multi-frequency cascade passivity-based control （PBC） is presented. Firstly, Fourier transform technique is applied to establish the multi-frequency DC model of the series converter, then the high-order system can be considered as a cascade low-order system onthe selected frequency model, anda novel PBC controller is designed based the cascade model. Theoretical analysis shows that it can not only realize flexible control for the series converter on frequency domain, but also achieve zero steady-state error control at selected frequency with inaccurate model parameters, and it can overcome the shortcoming that traditional PBC can hardly achieve zero steady-state error with inaccurate model parameters. Finally, experimental results verifythat the proposed control strategy is feasible.