The main application of off-grid solar photovoltaic (SPV) systems is water extraction in rural areas where access to the grid is restricted. In this application, photovoltaic (PV) and pump system regulation are crucial to increase its overall efficiency. In this context, this work presents a simple and efficient off-grid SPV water pumping system (SPVWPS). The designed system is based on a DC-DC boost converter, a three-phase DC-AC inverter, and a three-phase induction motor (IM) coupled to the centrifugal pump. The proposed solution is operated using a control strategy that associates an improved fractional open-circuit voltage (FOCV) method for maximum power point tracking (MPPT) and closed-loop scalar control. This association avoids the use of a speed sensor/encoder and a current sensor for the IM. Finally, the effectiveness of the proposed off-grid SPVWPS and its control system for both steady-state and dynamic conditions of insolation change is verified using a 1KVA rated prototype. The relevance of the drive is also checked in various operating conditions and is found to be adequate for pumping water. Moreover, the proposed method guarantees a fast response, less oscillations around the MPP, a system efficiency of 99%, and a high flow rate due to the extraction of maximum power.

中文翻译：

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基于改进分数开路电压MPPT技术的高效离网太阳能光伏抽水系统设计

离网太阳能光伏 (SPV) 系统的主要应用是在限制接入电网的农村地区取水。在此应用中，光伏 (PV) 和泵系统调节对于提高其整体效率至关重要。在这种情况下，这项工作提出了一种简单高效的离网 SPV 抽水系统 (SPVWPS)。设计的系统基于 DC-DC 升压转换器、三相 DC-AC 逆变器和与离心泵耦合的三相感应电机 (IM)。建议的解决方案使用控制策略进行操作，该策略将改进的分数开路电压 (FOCV) 方法与最大功率点跟踪 (MPPT) 和闭环标量控制相关联。这种关联避免了对 IM 使用速度传感器/编码器和电流传感器。最后，所提出的离网 SPVWPS 及其控制系统对日照变化的稳态和动态条件的有效性使用 1KVA 额定原型进行了验证。驱动器的相关性也在各种操作条件下进行检查，发现足以泵送水。此外，所提出的方法保证了快速响应、围绕 MPP 的振荡较少、系统效率为 99% 以及由于提取最大功率而产生的高流速。