PLL-Less Nonlinear Current-Limiting Controller for Single-Phase Grid-Tied Inverters: Design, Stability Analysis, and Operation Under Grid Faults
PLL-Less Nonlinear Current-Limiting Controller for Single-Phase Grid-Tied Inverters: Design, Stability Analysis, and Operation Under Grid Faults
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DOI：
10.1109/tie.2016.2564340
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发表时间：
2016-09
影响因子：
7.7
通讯作者：
G. Konstantopoulos;Qing-Chang Zhong;Wen-Long Ming
中科院分区：
文献类型：
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作者：
G. Konstantopoulos;Qing-Chang Zhong;Wen-Long Ming
提出了一种单相并网逆变器的非线性控制器，该控制器既可以在正常电网下运行，也可以在故障电网下运行，并保证了闭环系统的稳定性。该控制器与系统参数无关，不需要锁相环，可以实现所需的有功功率调节和单位功率因数运算。基于非线性输入-状态稳定理论，分析证明了逆变器电流始终保持在给定值以下，即使在暂态过程中，与电网变化或故障(短路或电压凹陷)无关。由于控制器的结构不需要任何开关、附加限制器或监控设备来实现，因此闭环系统的期望性能和稳定性得到了严格的证明。因此，在电网正常和故障情况下，证明了具有给定限流特性的并网逆变器的非线性稳定性。通过实验验证了该方法在不同电网运行条件下的有效性。
A nonlinear controller for single-phase grid-tied inverters, that can operate under both a normal and a faulty grid with guaranteed closed-loop stability, is proposed. The proposed controller acts independently from the system parameters, does not require a phase-locked loop, and can achieve the desired real power regulation and unity power factor operation. Based on nonlinear input-to-state stability theory, it is analytically proven that the inverter current always remains below a given value, even during transients, independently from grid variations or faults (short circuit or voltage sag). The desired performance and stability of the closed-loop system are rigorously proven since the controller has a structure that does not require any switches, additional limiters, or monitoring devices for its implementation. Therefore, nonlinear stability of a grid-tied inverter with a given current-limiting property is proven for both normal and faulty grid conditions. The effectiveness of the proposed approach is experimentally verified under different operating conditions of the grid.