一种提高LCL型并网逆变器电流控制性能的延时补偿方法  

A Delay Compensation Method to Improve the Current Control Performance of the LCL-type Grid-connected Inverter

作　　者：王林 孙鹏菊[1] 薛统宇 李强[1] 杜雄[1] 罗全明[1] WANG Lin;SUN Pengju;XUE Tongyu;LI Qiang;DU Xiong;LUO Quanming(State Key Laboratory of Power Transmission Equipment&System Security and New Technology(Chongqing University),Shapingba District,Chongqing 400044,China)

机构地区：[1]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆市沙坪坝区400044

出　　处：《中国电机工程学报》2020年第19期6320-6329,共10页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51677016)。

摘　　要：电容电流反馈有源阻尼广泛应用于LCL型并网逆变器中,可有效抑制系统的谐振尖峰。然而,在数字控制系统中,控制延时的存在会改变电容电流反馈有源阻尼的特性,使其等效在滤波电容两端的电阻的正负分界频率为fs/6,影响并网逆变器的稳定性和对电网阻抗的鲁棒性;同时,控制延时还会导致系统相位滞后,使得控制环路带宽受到限制。为此,提出一种兼顾有源阻尼特性和环路带宽的延时补偿方法,将有源阻尼等效电阻的正负分界频率扩大到0.43fs,大大提高系统的鲁棒性和动态性能。搭建一台3kW的单相LCL型并网逆变器样机,对比分析和实验结果验证了所提方法的有效性。Capacitive current feedback active damping is widely used in the LCL-type grid-connected inverter, which can effectively suppress the resonance peak of the system. However, the control delay in digital control system can change the characteristic of capacitive current feedback active damping and make the positive and negative boundary frequency of equivalent resistance is fs/6,which affects the stability of the grid-connected inverter and the robustness to grid impedance. At the same time, the control delay would introduce phase lag and limit the bandwidth of the control loop. Therefore, a delay compensation method considering both active damping characteristics and loop bandwidth was proposed, which can expand the positive and negative boundary frequency of equivalent resistance to 0.43 fs and greatly improve the robustness and dynamic performance of the system. A 3 kW single-phase LCL-type grid-connected inverter prototype was built. The comparative analysis and experimental results confirm the effectiveness of the proposed method.

关 键 词：并网逆变器 数字控制 延时补偿 鲁棒性 分界频率 

分 类 号：TM46[电气工程—电器]