摘要
为了满足光伏发电系统稳定性要求,解决传统非隔离单相逆变器存在的泄漏电流大和脉动功率导致的二次纹波电流含量大等问题,该文提出一种具有功率解耦功能的五开关共地逆变器。在全桥变换器基础上引入Boost变换器进行拓扑构造,拓扑结构紧凑,器件复用率高,可实现升降压功能。直流输入和交流输出共地将寄生电容短路,消除了共模电压,理论上泄漏电流为零。分析电流路径和控制策略,将脉动的功率储存在中间电容中,加入二次纹波抑制算法,抑制直流二次纹波,避免了直流环节需要使用体积大且笨重的电解电容,提高了系统的寿命。该文详细介绍所提拓扑结构的工作原理和实现功率解耦的控制策略,搭建了500 W的实验样机,在不同功率因数下进行功率解耦对比实验,验证了所提拓扑结构的良好性能和控制策略的有效性。
As a key component of the photovoltaic power generation system,the inverter significantly impacts the system’s stability.Traditional non-isolated single-phase inverters cannot perform buck-boost functions and have high leakage and large secondary ripple currents caused by pulsating power.This paper proposes a five-switch common-ground inverter with a power decoupling function to achieve buck-boost functionality.This topology solves the leakage current problem for common-ground topologies,decouples power in the mode,and incorporates secondary ripple suppression control to mitigate the inherent secondary ripple of single-phase inverters.Firstly,the proposed topology introduces a Boost converter based on the full-bridge converter to construct a compact and efficient design.The topology utilizes a minimal number of switching devices,i.e.,five switches without diodes.Hence,the device reuse rate is enhanced,and the stability of the photovoltaic power generation system is ensured.The topology can achieve buck and boost functionalities by integrating the Boost converter,providing greater flexibility and adaptability to varying input conditions.Secondly,the paper delves into the mechanism and impact of secondary ripples.A detailed current path is planned to store the pulsating power in the intermediate capacitor,decoupling effective power without additional devices.The proposed secondary ripple suppression strategy further reduces the secondary ripple in the input current,ensuring smooth and stable operation.The need for large,bulky electrolytic capacitors in the DC link is eliminated,enhancing the system’s lifespan and reliability.Finally,a simulation model and experimental platform are built to verify the proposed topology and the control strategy under different power factors.The simulation and experimental results demonstrate that the proposed topology and control strategy significantly suppress the secondary ripple of DC current at unity power factors of PF=0.8 and PF=−0.8,greatly reducing the pulsation of DC current.The total harmonic distortion(THD)of the output voltage and current is maintained below 2.0%.When the inverter output power transitions from 500 W to 250 W and back to 500 W,the dynamic response time is approximately 0.65 s,with the voltage fluctuation of the intermediate capacitor not exceeding 40 V.The common-mode voltage is approximately 0 V,and the root mean square value of the leakage current is only 7.25 mA,meeting the safety standard DIN VDE 0126-1-1.At a rated power of 500 W,the maximum efficiency can reach 95.62%.The following conclusions can be drawn.(1)The proposed topology is compact without electrolytic capacitors.It has a wide input/output range and low leakage current,which is suitable for photovoltaic power generation systems.(2)The power decoupling function and the proposed control strategy effectively suppress the secondary ripple of DC current under different power factors.(3)Compared to existing research,the proposed topology achieves the most functions with the least number of devices.
作者
陈贺驰
杨江朋
张恒鹏
白方林
舒泽亮
Chen Hechi;Yang Jiangpeng;Zhang Hengpeng;Bai Fanglin;Shu Zeliang(School of Electrical Engineering,Southwest Jiaotong University,Chengdu 611756,China)
出处
《电工技术学报》
北大核心
2025年第18期5988-5997,共10页
Transactions of China Electrotechnical Society
基金
国家自然科学基金资助项目(52077183,52207138)。
关键词
非隔离型逆变器
升降压
无电解电容
功率解耦
Non-isolated inverter
Boost and Buck converter
non-electrolytic capacitor
power decoupling
