多包络线谐振软开关逆变器控制策略

为了满足光伏微型逆变器高功率密度、高性能、低总谐波畸变率(total harmonic distortion,THD)的要求,文中基于临界电流模式提出一种多包络线谐振软开关逆变器控制策略,通过进行开关管的分时控制达到平衡电感电流上升下降时间的目的,从而缓解过零点畸变。随后,详细介绍多包络线谐振软开关逆变器控制策略的工作模态,并从软开关、开关频率、开关管损耗与逆变效率、过零点畸变程度等方面与传统临界电流模式进行对比分析。为验证控制策略的有效性,文中基于PSIM搭建了500 W谐振软开关单相全桥逆变器进行开环仿真验证。仿真结果表明,与传统的单极性临界电流模式相比,多包络线临界电流模式可以有效优化过零点问题,能够滤除谐波、降低THD,并且实现零电流开关(zero current switch,ZCS)和全部开关管的零电压开关(zero voltage switch,ZVS)。

Control strategy of multi-envelope resonant soft switching inverter

In order to meet the requirements of high power density,high performance and low total harmonic distortion (THD) for photovoltaic microinverters, a multi-envelope resonant soft-switch inverter control strategy based on the critical current mode is proposed. Through time-sharing control of switching tubes,the rise and fall time of inductance current is balanced,so as to alleviate zero-crossing distortion. Then,the working mode of the control strategy of multi-envelope resonant soft-switch inverter is introduced in detail,and compared with the traditional critical current mode in terms of soft switch,switching frequency,switching tube loss and inverter efficiency,zero-crossing distortion degree. In order to verify the effectiveness of the control strategy,a 500 W soft-switched single-phase full-bridge inverter is built based on PSIM for open-loop simulation verification. The simulation results indicate that the multi-envelope mode,when compared to the traditional unipolar critical current mode,offers several advantages. These advantages include effective optimization of the zero crossing issue,harmonic filtration leading to reduced THD,and the achievement of zero current switch (ZCS) and zero voltage switch (ZVS) for all switches.