A composite passive and active power decoupling method is proposed and optimized for a photovoltaic (PV) inverter. The proposed composite power decoupling (CPD) method has the following merits: 1) the dc side passive power decoupling (DC-PPD) can be automatically activated/deactivated according to the solar power to maintain more than 99% maximum power point tracking efficiency and low total harmonic current distortion (THDi); 2) the film capacitor with high reliability can be used due to the optimization of the energy buffer, e.g., a reduction of 52% and 23% in capacitance (or buffer energy) compared to DC-PPD and ac side active power decoupling, respectively; 3) control scheme developed in the d-q frame has more simple structure and requires less measurements than the existing methods. The experimental results show that the proposed CPD can dynamically control the dc-link voltage ripple under various conditions such as the abrupt change of the solar power and the load. Besides, low dc-link voltage ripple and low THDi are achieved in both steady-state and transient periods. Particularly when the solar power is less than 74%, the proposed CPD (with 261 μ F) has better performance than the traditional used PPD (with 1120 μ F). This article is accompanied by a video demonstrating the parameters optimization and measured waveforms.

中文翻译：

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一种优化能量缓冲的光伏逆变器复合功率解耦方法

针对光伏 (PV) 逆变器提出并优化了一种复合无源和有源功率解耦方法。所提出的复合功率去耦（CPD）方法具有以下优点：1）直流侧无源功率去耦（DC-PPD）可以根据太阳能功率自动激活/停用，以保持99%以上的最大功率点跟踪效率和低总谐波电流失真 (THDi)；2）由于能量缓冲的优化，可以使用高可靠性的薄膜电容器，例如与DC-PPD和ac侧有功功率去耦相比，电容（或缓冲能量）分别减少52%和23% ; 3) 开发的控制方案dq 框架结构更简单，比现有方法需要更少的测量。实验结果表明，所提出的 CPD 可以在太阳能和负载的突然变化等各种条件下动态控制直流母线电压纹波。此外，在稳态和瞬态期间都实现了低直流链路电压纹波和低 THDi。特别是当太阳能发电量低于 74% 时，建议的 CPD（261μ F) 比传统使用的 PPD（具有 1120 μF)。本文附有演示参数优化和测量波形的视频。