In this paper, a perturb and observe (P&O) based voltage regulator (POVR) and a capacitor compensator (CC) circuit are proposed for the implementation on 31-level asymmetrical switch-diode based multi-level DC-link (MLDCL) inverter. Since the application of MLDCL in a standalone photovoltaic (PV) system requires constant DC voltages from PV panels, the POVR strategy is deployed to regulate the voltage along with the capability to deliver the maximum power at full load. Boost DC-DC converters are used as the interface between the panels and the inverter for the POVR operation. The results show that POVR is capable of achieving the desired fixed DC voltages even under varying environmental and load conditions, with a steady 230 V at the output. At full load, the standalone system successfully delivers 97.21% of the theoretical maximum power. Additionally, CC is incorporated to mitigate voltage spikes at the output when supplying power to inductive loads. It successfully eliminates the spikes and also reduces the total harmonic distortion (THD) of output current and voltage from more than 10% to less than 5%, as recommended in IEEE 519 standard.

中文翻译：

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带有扰动和基于观测的电压调节器和电容器补偿器的光伏能源系统不对称多电平直流链路逆变器

本文提出了一种基于扰动和观测（P＆O）的电压调节器（POVR）和电容器补偿器（CC）电路，以实现基于31级非对称开关二极管的多级直流母线（MLDCL）逆变器。由于MLDCL在独立光伏（PV）系统中的应用需要来自光伏面板的恒定DC电压，因此采用了POVR策略来调节电压，并具有在满负载下提供最大功率的能力。Boost DC-DC转换器用作面板和逆变器之间的接口，以进行POVR操作。结果表明，即使在变化的环境和负载条件下，POVR仍能够实现所需的固定DC电压，并且输出端具有稳定的230V。在满负载下，独立系统成功提供了理论最大功率的97.21％。此外，并入CC可以减轻向感性负载供电时输出端的电压尖峰。它成功消除了尖峰，并且按照IEEE 519标准的建议，将输出电流和电压的总谐波失真（THD）从大于10％减小到小于5％。