针对传统加权平均电流(weighted average current,WAC)控制策略未考虑数字控制延时使系统出现相位滞后而导致系统带宽减小、鲁棒性差的问题,提出了基于准比例谐振控制和超前补偿器结合的WAC控制策略。首先,引入电容电流反馈,抑制反向谐...针对传统加权平均电流(weighted average current,WAC)控制策略未考虑数字控制延时使系统出现相位滞后而导致系统带宽减小、鲁棒性差的问题,提出了基于准比例谐振控制和超前补偿器结合的WAC控制策略。首先,引入电容电流反馈,抑制反向谐振峰;其次,在逆变桥传递函数处串联超前补偿器,提高系统的相位裕度;最后,应用准比例谐振控制器作为电流调节器,提高基频增益、降低系统的静态误差。经仿真验证,所提控制策略对弱电网具有良好的适应能力,并网电流谐波畸变率从1.84%降低到0.26%,增强了系统的鲁棒性、改善了并网电流的质量。展开更多
加权平均电流(weighted average current,WAC)控制方法由于其环路降阶特性,在并网逆变器系统中得到了广泛的应用。然而,传统WAC控制方法并未充分考虑数字控制延时对并网逆变器系统造成的影响。该文分析表明,数字控制延时引入的相位滞后...加权平均电流(weighted average current,WAC)控制方法由于其环路降阶特性,在并网逆变器系统中得到了广泛的应用。然而,传统WAC控制方法并未充分考虑数字控制延时对并网逆变器系统造成的影响。该文分析表明,数字控制延时引入的相位滞后导致传统WAC控制方法不再具备环路降阶特性,而使得环路增益中出现一个随电网阻抗变化的反向谐振峰,使并网系统存在失稳的风险。针对此问题,该文提出一种基于超前补偿器的高鲁棒性WAC控制策略,该策略利用前馈通道中引入的超前补偿器来补偿反向谐振峰频率范围内的相位滞后,以此来实现环路降阶特性及弱电网适应性。对比分析和实验研究表明,所提控制策略能够保留传统WAC控制的降阶优点,同时对弱电网亦有很强的适应能力。展开更多
为解决加权平均电流反馈(weighted average current feedback,WACC)控制下,并网电流存在谐振且开环增益中存在反谐振现象的问题,提出了一种改进的WACC方法。首先,引入电容电流反馈控制,以提升并网电流质量;然后,通过引入补偿环节,保证...为解决加权平均电流反馈(weighted average current feedback,WACC)控制下,并网电流存在谐振且开环增益中存在反谐振现象的问题,提出了一种改进的WACC方法。首先,引入电容电流反馈控制,以提升并网电流质量;然后,通过引入补偿环节,保证控制系统的降阶特性,从而有效抑制计及数字控制延时情况下控制系统中出现的反谐振和并网电流谐振。研究结果表明,所提方法可有效地将控制系统的幅值裕度从2.2 d B提升至8 d B,增强了系统鲁棒性,将并网电流谐波畸变率从5.46%降低到0.71%,改善了并网电流质量。所提方法可为实际工程中的并网逆变器控制提供参考。展开更多
针对传统LCL型并网逆变器存在谐振尖峰和传统加权平均电流控制的并网逆变器存在并网电流谐波含量大的问题,提出了一种以滤波电容电流为内环、加权平均电流为外环的改进型加权平均电流控制策略;然后以容量为3 k W的单相全桥并网逆变器为...针对传统LCL型并网逆变器存在谐振尖峰和传统加权平均电流控制的并网逆变器存在并网电流谐波含量大的问题,提出了一种以滤波电容电流为内环、加权平均电流为外环的改进型加权平均电流控制策略;然后以容量为3 k W的单相全桥并网逆变器为例进行了仿真,验证了该策略的可行性.仿真结果表明,与传统有源阻尼控制策略、传统加权平均电流控制策略相比,采用本文控制策略的并网逆变器能够以总谐波失真为1.38%、功率因数为0.998实现并网,更好地满足了并网要求.展开更多
Receding horizon H∞ control scheme which can deal with both the H∞ disturbance attenuation and mean square stability is proposed for a class of discrete-time Markovian jump linear systems when minimizing a given qua...Receding horizon H∞ control scheme which can deal with both the H∞ disturbance attenuation and mean square stability is proposed for a class of discrete-time Markovian jump linear systems when minimizing a given quadratic performance criteria. First, a control law is established for jump systems based on pontryagin’s minimum principle and it can be constructed through numerical solution of iterative equations. The aim of this control strategy is to obtain an optimal control which can minimize the cost function under the worst disturbance at every sampling time. Due to the difficulty of the assurance of stability, then the above mentioned approach is improved by determining terminal weighting matrix which satisfies cost monotonicity condition. The control move which is calculated by using this type of terminal weighting matrix as boundary condition naturally guarantees the mean square stability of the closed-loop system. A sufficient condition for the existence of the terminal weighting matrix is presented in linear matrix inequality （LMI） form which can be solved efficiently by available software toolbox. Finally, a numerical example is given to illustrate the feasibility and effectiveness of the proposed method.展开更多
文摘针对传统加权平均电流(weighted average current,WAC)控制策略未考虑数字控制延时使系统出现相位滞后而导致系统带宽减小、鲁棒性差的问题,提出了基于准比例谐振控制和超前补偿器结合的WAC控制策略。首先,引入电容电流反馈,抑制反向谐振峰;其次,在逆变桥传递函数处串联超前补偿器,提高系统的相位裕度;最后,应用准比例谐振控制器作为电流调节器,提高基频增益、降低系统的静态误差。经仿真验证,所提控制策略对弱电网具有良好的适应能力,并网电流谐波畸变率从1.84%降低到0.26%,增强了系统的鲁棒性、改善了并网电流的质量。
文摘加权平均电流(weighted average current,WAC)控制方法由于其环路降阶特性,在并网逆变器系统中得到了广泛的应用。然而,传统WAC控制方法并未充分考虑数字控制延时对并网逆变器系统造成的影响。该文分析表明,数字控制延时引入的相位滞后导致传统WAC控制方法不再具备环路降阶特性,而使得环路增益中出现一个随电网阻抗变化的反向谐振峰,使并网系统存在失稳的风险。针对此问题,该文提出一种基于超前补偿器的高鲁棒性WAC控制策略,该策略利用前馈通道中引入的超前补偿器来补偿反向谐振峰频率范围内的相位滞后,以此来实现环路降阶特性及弱电网适应性。对比分析和实验研究表明,所提控制策略能够保留传统WAC控制的降阶优点,同时对弱电网亦有很强的适应能力。
文摘为解决加权平均电流反馈(weighted average current feedback,WACC)控制下,并网电流存在谐振且开环增益中存在反谐振现象的问题,提出了一种改进的WACC方法。首先,引入电容电流反馈控制,以提升并网电流质量;然后,通过引入补偿环节,保证控制系统的降阶特性,从而有效抑制计及数字控制延时情况下控制系统中出现的反谐振和并网电流谐振。研究结果表明,所提方法可有效地将控制系统的幅值裕度从2.2 d B提升至8 d B,增强了系统鲁棒性,将并网电流谐波畸变率从5.46%降低到0.71%,改善了并网电流质量。所提方法可为实际工程中的并网逆变器控制提供参考。
文摘针对传统LCL型并网逆变器存在谐振尖峰和传统加权平均电流控制的并网逆变器存在并网电流谐波含量大的问题,提出了一种以滤波电容电流为内环、加权平均电流为外环的改进型加权平均电流控制策略;然后以容量为3 k W的单相全桥并网逆变器为例进行了仿真,验证了该策略的可行性.仿真结果表明,与传统有源阻尼控制策略、传统加权平均电流控制策略相比,采用本文控制策略的并网逆变器能够以总谐波失真为1.38%、功率因数为0.998实现并网,更好地满足了并网要求.
基金supported by the National Natural Science Foundation of China (60974001)Jiangsu "Six Personnel Peak" Talent-Funded Projects
文摘Receding horizon H∞ control scheme which can deal with both the H∞ disturbance attenuation and mean square stability is proposed for a class of discrete-time Markovian jump linear systems when minimizing a given quadratic performance criteria. First, a control law is established for jump systems based on pontryagin’s minimum principle and it can be constructed through numerical solution of iterative equations. The aim of this control strategy is to obtain an optimal control which can minimize the cost function under the worst disturbance at every sampling time. Due to the difficulty of the assurance of stability, then the above mentioned approach is improved by determining terminal weighting matrix which satisfies cost monotonicity condition. The control move which is calculated by using this type of terminal weighting matrix as boundary condition naturally guarantees the mean square stability of the closed-loop system. A sufficient condition for the existence of the terminal weighting matrix is presented in linear matrix inequality （LMI） form which can be solved efficiently by available software toolbox. Finally, a numerical example is given to illustrate the feasibility and effectiveness of the proposed method.
