同步参考坐标系锁相环是高压直流(high voltage direct current，HVDC)同步触发控制系统中广泛应用的一种窄带宽锁相环，在交流系统故障引起相位跳变情况下，其动态响应缓慢。为增大锁相环的带宽，一种滑动平均滤波器(moving average filter，MAF)被前置于锁相环路，然而MAF本身存在响应延迟，制约了锁相环的同步速度。为了缓解响应延迟问题，文中提出一种考虑MAF延时和前馈补偿的HVDC快速锁相环。首先，利用MAF线性暂态特征预测相位变化，并分别针对故障接入和切除引起的相位跳变问题提出不同的补偿策略;接着，利用不变性原理对锁相环路进行前馈补偿，在负反馈控制和前馈补偿共同构成的复合校正控制系统的作用下，锁相环能够在较小PI参数下实现快速响应;最后，将所提快速锁相环在CIGRE HVDC标准模型和三峡—上海直流工程模型中进行仿真验证。结果表明，该快速锁相环能够有效缓解滤波器响应延迟的制约，缩短失锁时间，进而提高高压直流逆变侧抵御换相失败的能力。
HVDC Fast Phase-locked Loop Considering MAF Delay and Feedforward Compensation
Synchronous reference frame phase-locked loop(SRF-PLL)is a narrow-bandwidth PLL widely used in high voltage direct current(HVDC)synchronous firing control systems,whose dynamic response is slow in the case of phase jumps caused by AC system faults.In order to increase the bandwidth of PLL,a moving average filter(MAF)is placed in front of PLL.However,there is a response delay in MAF,which restricts the synchronous speed of PLL.In order to alleviate the problem of response delay,this paper proposes an HVDC fast PLL considering MAF delay and feedforward compensation.First,the linear transient characteristic of MAF is used to predict the phase change,and different compensation strategies are proposed for the phase jump caused by fault being connected and removed,respectively.Then,the invariance principle is used to perform feedforward compensation on PLL.Under the action of the composite correction control system composed of negative feedback control and feedforward compensation,PLL can achieve fast response with small PI parameters.Finally,the proposed fast PLL is simulated and verified in the CIGRE HVDC benchmark model and the Three Gorges-Shanghai DC project model.The results show that the fast PLL can effectively alleviate the restriction of the filter response delay,shorten the loss-of-lock time,and further improve the ability of the HVDC inverter side to resist commutation failure.
high voltage direct current(HVDC)phase-locked loop(PLL)the delay of filterfeedforward compensationcommutation failure
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维普
