This article proposes the development of a model reference adaptive controller (MRAC) for grid integration of a single-stage three-phase grid-connected photovoltaic system (GCPVS). The performance of a GCPVS is influenced by uncertainties such as measurement noise, solar irradiance, photovoltaic (PV) operating point, aging of the dc-link capacitor, and variation in the filter impedance. In order to achieve the desired tracking performance under both nominal and parametric uncertainties, MRACs are designed for both the outer PV voltage control loop and the inner grid current control loop. The proposed control scheme comprises a reference model and a Lyapunov-based parameter adaptation scheme, which provides the nominal tracking performance despite uncertainties in the GCPVS dynamics. As a result, improved performance of the GCPVS is achieved in terms of low dc-link voltage ripple, superior power extraction, and improved grid power quality. The performance of the proposed adaptive controller is verified by pursuing simulation in MATLAB/Simulink followed by experimentation on a 2.5-kW GCPVS. The control algorithm is implemented in real time on the SPARTAN-6 FPGA scheme. The efficiency of maximum power point tracking (MPPT) is obtained as 99.92%. The total harmonic distortion of grid currents and voltages at the point of common coupling is found to be less than 3%, which is well within the limit specified by the IEEE-1547 standard.

中文翻译：

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三相并网光伏系统级联模型参考自适应控制器的设计与实时实现


本文提出开发一种用于单级三相并网光伏系统（GCPVS）并网的模型参考自适应控制器（MRAC）。 GCPVS 的性能受到测量噪声、太阳辐照度、光伏 (PV) 工作点、直流母线电容器老化以及滤波器阻抗变化等不确定性的影响。为了在标称和参数不确定性下实现所需的跟踪性能，MRAC 被设计用于外部光伏电压控制环路和内部电网电流控制环路。所提出的控制方案包括参考模型和基于李亚普诺夫的参数自适应方案，尽管 GCPVS 动态存在不确定性，但该方案仍提供标称跟踪性能。因此，GCPVS 在低直流母线电压纹波、卓越的功率提取和改善的电网电能质量方面实现了改进的性能。通过在 MATLAB/Simulink 中进行仿真，然后在 2.5 kW GCPVS 上进行实验，验证了所提出的自适应控制器的性能。控制算法在SPARTAN-6 FPGA方案上实时实现。最大功率点跟踪（MPPT）效率为99.92%。公共耦合点电网电流和电压的总谐波失真小于3%，完全在IEEE-1547标准规定的限值之内。