静止同步补偿器电压控制策略

为寻求性能优良、容易实现的配电静止同步补偿器(DSTATCOM)的电压控制策略,根据DSTATCOM系统中的瞬时功率平衡理论,推导出了DSTATCOM用于控制电压时的直接电压控制策略。该控制策略中无需电流检测电路,跟传统的串级控制相比较具有控制简单、响应速度快等优点;针对直接电压控制策略中控制器的控制性能受系统参数影响较大的缺陷,提出了DSTATCOM的直接电压模糊PI控制策略,使根据瞬时功率平衡的直接电压控制具有更好的控制性能;同时考虑到实际电网中的电压不平衡现象普遍存在,在DSTATCOM电压控制器中引入电网电压负序分量的前馈控制,从而有效的提高了DSTATCOM在电网电压不平衡条件下的生存能力。理论分析和仿真结果证明了所提控制方法的正确性和有效性。

New Control Strategy of Distribution Static Synchronous Compensator Used for Voltage Control

Based on the balance of the instantaneous power of the distribution static synchronous compensator(DSTATCOM) system the direct output voltage control strategy for voltage control is proposed.In the proposed control strategy,the current detection circuit is not demanded.Compared with the cascade control strategy the proposed control strategy has the merits of simple structure and fast response time.But the direct output voltage control strategy has not excellent control performance when the parameters of the system change.In order to overcome this problem the Fuzzy PI control is proposed.The Fuzzy PI can adjust the PI parameters according to the performance index of the control system and has the adaptability.The Fuzzy PI control makes the direct output voltage control strategy possess the better control performance.By consideration of the unbalance of the main source voltage,a negative sequence voltage feedforward control strategy is adopted in order to improve the survival capability of the DSTATCOM under unbalanced conditions.The effective and validity of the control strategy are verified by the theoretic analysis and digital simulation.Under fixed parameter condition the control strategy proposed in this paper has the better dynamical and steady performances than conventional PI control.When the parameters of the control system changed the conventional PI control in lost stability,the performance of the control strategy proposed in this paper is not affected.