High Weighted Efficiency in Single-Phase Solar Inverters by a Variable-Frequency Peak Current Controller
High Weighted Efficiency in Single-Phase Solar Inverters by a Variable-Frequency Peak Current Controller
复制标题
DOI：
10.1109/tpel.2015.2399418
复制
发表时间：
2016
影响因子：
6.7
通讯作者：
Y. Levron;R. Erickson
中科院分区：
文献类型：
--
作者：
Y. Levron;R. Erickson
本文讨论了一种在太阳能微型逆变器中实现高加权效率的控制方法。微型逆变器的一个挑战是在一系列输出功率上实现高效率。为了应对这一挑战，建议的控制器提供了两个主要优点，以实现这样的效率曲线，即随功率变化的开关频率，以及使电感能够进行高效磁化设计的低峰值电流。在高功率时，开关频率提高以最小化均方根(RMS)电流，而在低功率时，开关频率降低以最小化开关损耗。由于峰值电感电流低，电感可以设计成较少的导线匝数或较低的磁通密度，因此效率很高。所提出的恒峰值电流切换方案由逐周期预测控制器实现，该控制器使用快速积分器来控制切换周期，从而获得高带宽和稳定性。该控制器只检测峰值电感电流，因此不需要昂贵的平均电流传感器。我们展示了一个使用300瓦太阳能电池板的低成本逆变器样机。该样机使用标准硅器件和一个360μH的小电感来实现99.15%的加权效率。
This paper discusses a control method that achieves high weighted efficiency in solar microinverters. A challenge in microinverters is to achieve high efficiency over a range of output powers. To address this challenge, the proposed controller presents two primary benefits that enable such an efficiency profile, a switching frequency that scales with power, and a low peak current that enables efficient magnetic design of the inductor. At high powers, the switching frequency increases to minimize the root-mean-square (rms) current, and at low powers, the switching frequency decreases to minimize the switching loss. Since the peak inductor current is low, the inductor may be designed with fewer turns of wire, or with lower flux density, and is thus highly efficient. The proposed constant peak current switching scheme is implemented by a cycle-by-cycle predictive controller that uses a fast integrator to control the switching period, achieving high bandwidth and stability. This controller senses only the peak inductor current and, therefore, does not require expensive average current sensors. We demonstrate a low-cost inverter prototype with a 300-W solar panel. The prototype uses standard silicon devices and a small inductor of 360 μH to achieve a weighted efficiency of 99.15%.