A Coordinated Compensation Strategy for Module Mismatch of CHB-PV Systems Based on Improved LS-PWM and Reactive Power Injection
The cascaded H-bridge (CHB) converter has become a promising candidate topology for utility-scale photovoltaic systems thanks to merits like modular structure, distributed maximum power point tracking (MPPT), and direct distribution grid access without medium-voltage transformers. However, module mi...
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Published in | IEEE transactions on industrial electronics (1982) Vol. 66; no. 4; pp. 2825 - 2836 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
New York
IEEE
01.04.2019
The Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
Subjects | |
Online Access | Get full text |
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Summary: | The cascaded H-bridge (CHB) converter has become a promising candidate topology for utility-scale photovoltaic systems thanks to merits like modular structure, distributed maximum power point tracking (MPPT), and direct distribution grid access without medium-voltage transformers. However, module mismatches arising from nonideal elements like partial shading and parameter variations pose a technical challenge for such systems. If not dealt with properly, module mismatches can lead to adverse effects like unbalanced dc-link voltages of the modules, distortion of grid current, and reduced power generation. Conventional methods, such as reactive power compensation and level-shifted pulsewidth modulation (LS-PWM) based compensation, can alleviate this issue, but their performances are still limited by the allowable modulation range of power converters. In this paper, a compensation strategy combining reactive power compensation with a novel modulation method is proposed to extend the operating range in terms of module mismatch. Experimental results on a 2.4 kW/208 V single-phase setup are presented and have demonstrated that the proposed method can not only ride through a larger range of module mismatches but also improve solar power utilization and system efficiency owing to reduced switching events, noncompromised MPPT, and less required reactive power. |
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Bibliography: | USDOE Office of Electricity Delivery and Energy Reliability (OE) AC05-00OR22725 |
ISSN: | 0278-0046 1557-9948 |
DOI: | 10.1109/TIE.2018.2842789 |