Abstract This research paper presents stand-alone and grid-tied micro-inverters for Photo Voltaic (PV) applications. It also addresses several key technical control related issues in the domain of micro-inverter technology for PVs. One portion of this research deals with the digital control strategies for micro-inverters. One Sampling Ahead Preview (OSAP) control has been used to track sinusoidal ac voltage/current of micro-inverters. Microinverter is controlled and analyzed in stand-alone and grid-tied states of operation. In each state, initially the OSAP controller is applied and inverter performance is analyzed. An improved OSAP controller (conventional OSAP + digital resonant controller) is also then applied to compensate the drawbacks of OSAP alone and better track the reference signal. Simulation results are provided which confirm the effectiveness of the proposed control for micro-inverter based solar systems. Another contribution is performance analysis of the proposed control scheme with a Maximum Power Point Tracking (MPPT) strategy. Atmospheric conditions being one of the most influential and uncontrollable factor in solar generation, vary the output of the solar panel nonlinearly. MPPT techniques enable PV panels to operate at the optimal power point and hence generate maximum power. Therefore, various MPPT strategies were considered, and finally an improved variable step size P&O MPPT strategy is used in this research work. Simulation results are given to demonstrate the validity of P&O MPPT strategy along with the proposed control scheme in the events of step changes in irradiation and ac current.

中文翻译：

---

并网光伏微型逆变器的数字控制

摘要 本研究论文介绍了用于光伏 (PV) 应用的独立和并网微型逆变器。它还解决了光伏微型逆变器技术领域中的几个关键技术控制相关问题。本研究的一部分涉及微型逆变器的数字控制策略。一种提前采样预览 (OSAP) 控件已用于跟踪微逆变器的正弦交流电压/电流。微型逆变器在独立和并网运行状态下进行控制和分析。在每种状态下，最初应用 OSAP 控制器并分析逆变器性能。然后还应用了改进的 OSAP 控制器（常规 OSAP + 数字谐振控制器），以补偿单独 OSAP 的缺点并更好地跟踪参考信号。提供的仿真结果证实了所提出的基于微型逆变器的太阳能系统的控制的有效性。另一个贡献是使用最大功率点跟踪 (MPPT) 策略对建议的控制方案进行性能分析。大气条件是太阳能发电中最有影响和最不可控的因素之一，它会非线性地改变太阳能电池板的输出。MPPT 技术使光伏电池板能够在最佳功率点运行，从而产生最大功率。因此，考虑了各种 MPPT 策略，最后在本研究工作中使用了改进的可变步长 P&O MPPT 策略。仿真结果证明了 P&O MPPT 策略以及所提出的控制方案在辐照和交流电流发生阶跃变化的情况下的有效性。