In the conventional photovoltaic (PV) fed quasi-Z (qZ) network-based impedance-source converters (ISCs), the PV array is connected to their input, whereas in the proposed topology in this article, an additional array is paralleled to the second qZ-network's capacitor (C2). This modification allows harvesting more PV power through full utilization of the employed qZ-network in the classical ISCs. Moreover, the proposal offers higher conversion efficiency since the current in the second qZ-network's inductor (iL2) is smaller. The voltage of the added PV array (PV2) is independent of the voltage of the primary array (PV1) in a wide range, which promotes tracking their maximum power points (MPPs) separatly, achieving a higher efficiency even under partial shading. The use of two separate maximum power point trackings (MPPTs) in one converter is a challenge since the perturbation done by the first MPPT alters the power in PV2 as well, and vice versa. Therefore, a two MPPs tracker algorithm, which perturbs two parameters and observes four variables, is proposed for the presented converter. The theoretical analysis is validated through realtime hardware-in-the-loop tests, and it demonstrates that at least 11% more power can be harvested compared to the conventional qZ-network-based ISC.

中文翻译：

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双输入准 Z 源光伏逆变器：动态建模、设计和控制


在传统的光伏 (PV) 馈电准 Z (qZ) 网络阻抗源转换器 (ISC) 中，光伏阵列连接到其输入，而在本文提出的拓扑中，额外的阵列并联到第二个 qZ 网络的电容器 (C2)。这种修改允许通过充分利用经典 ISC 中使用的 qZ 网络来收集更多的光伏电力。此外，由于第二个 qZ 网络电感器 (iL2) 中的电流较小，因此该方案提供了更高的转换效率。所添加的光伏阵列（PV2）的电压在很大范围内独立于主阵列（PV1）的电压，这有助于单独跟踪它们的最大功率点（MPP），即使在部分遮蔽下也能实现更高的效率。在一个转换器中使用两个独立的最大功率点跟踪 (MPPT) 是一项挑战，因为第一个 MPPT 所做的扰动也会改变 PV2 中的功率，反之亦然。因此，为所提出的转换器提出了一种双 MPP 跟踪算法，该算法扰动两个参数并观察四个变量。理论分析通过实时硬件在环测试得到验证，表明与传统的基于 qZ 网络的 ISC 相比，可以获得至少 11% 以上的功率。