Abstract

The reference input dc voltage of grid connected voltage source inverter (GCVSI) is altered in this article based on power (both active and reactive) injection from GCVSI for minimizing inverter switching losses, and total harmonic distortion (THD) of grid current. If the GCVSI is exclusively used for actual power injection from the photo-voltaic (PV) system to the utility grid, the needed input dc voltage of GCVSI is twice the utility grid phase peak voltage. According to the literature, GCVSI is also used to compensate for power quality issues, and in these circumstances, the dc-link voltage value is determined by the maximum power injection of GCVSI. Under reduced load, and reduced power generation from the PV system, keeping maximum GCVSI input dc voltage reference causes extra voltage stress at GCVSI switches, and the grid current THD is worse due to high ripple current in filter inductance. Therefore, to reduce the inverter switching losses and to improve the grid current THD, the relationship between the GCVSI input dc voltage reference and the power flow from GCVSI has been formulated. The proposed work is verified using simulation studies, as well as hardware studies, and the results are compared with existing methods for validation.

摘要

本文基于来自 GCVSI 的功率（有功和无功）注入改变了并网电压源逆变器 (GCVSI) 的参考输入直流电压，以最大限度地降低逆变器开关损耗和电网电流的总谐波失真 (THD)。如果 GCVSI 专门用于从光伏 (PV) 系统到公用电网的实际功率注入，则 GCVSI 所需的输入直流电压是公用电网相位峰值电压的两倍。根据文献，GCVSI 也用于补偿电能质量问题，在这种情况下，直流母线电压值由 GCVSI 的最大功率注入决定。在负载降低和光伏系统发电量减少的情况下，保持最大 GCVSI 输入直流电压基准会在 GCVSI 开关处产生额外的电压应力，由于滤波电感中的纹波电流较大，电网电流 THD 更差。因此，为降低逆变器开关损耗并改善电网电流 THD，制定了 GCVSI 输入直流电压基准与来自 GCVSI 的功率流之间的关系。使用模拟研究和硬件研究验证了所提出的工作，并将结果与​​现有的验证方法进行了比较。