ABSTRACT

DC-DC converters are widely used in solar power systems to extract maximum power from solar photovoltaic (SPV) sources by matching the reflected load resistance to the internal resistance of the SPV source. This paper proposes a non-isolated buck-boost converter with extended range of voltage gain operating within practical limits of duty ratio. The gain of the proposed converter has been enhanced by lifting the voltage level of a classical buck-boost converter through a simple auxiliary network, comprising a semiconductor switch, an inductor and a capacitor. In the present work, the proposed converter has been used to extract maximum power from the SPV source with wide range of load resistance and under wide variation in solar irradiance and ambient temperature. Steady-state analysis of voltage gain, boundary condition analysis and design guidelines of the proposed converter have been presented in this paper. Finally, the theoretical analysis has been validated by experimentally verifying the performance of the proposed converter with a laboratory scale hardware prototype, tested with DSPIC33FJ32MC204 microcontroller for maximum power point tracking (MPPT) of SPV source. Real-time performance of the proposed converter has been found to match the predicted behaviour of the SPV system.

摘要

DC-DC 转换器广泛用于太阳能发电系统，通过将反射负载电阻与 SPV 源的内阻相匹配，从太阳能光伏 (SPV) 源中提取最大功率。本文提出了一种非隔离式降压-升压转换器，它具有在实际占空比限制内工作的扩展电压增益范围。通过一个简单的辅助网络（包括一个半导体开关、一个电感器和一个电容器）提升经典降压-升压转换器的电压电平，所提出的转换器的增益得到了增强。在目前的工作中，所提出的转换器已被用于从具有宽负载电阻范围和太阳辐照度和环境温度变化很大的 SPV 源中提取最大功率。电压增益的稳态分析，本文提出了所提出的转换器的边界条件分析和设计指南。最后，通过使用实验室规模的硬件原型对所提出的转换器的性能进行实验验证，理论分析得到了验证，并使用 DSPIC33FJ32MC204 微控制器对 SPV 源的最大功率点跟踪 (MPPT) 进行了测试。已发现所提出的转换器的实时性能与 SPV 系统的预测行为相匹配。