新型准Z源三电平逆变器的性能分析及其并网控制特性

Performance Analysis and Grid-Connected Control Characteristics of a Novel Quasi-Z Source Three-Level Inverter

针对传统Z源逆变器起动冲击电流大,升压能力不足,电容电压应力大等局限性,提出了一种准Z源中性点钳位式(neutral point clamped, NPC)三电平逆变器拓扑结构。首先,分析了所提结构的工作原理及其准Z源参数的设计,在低直通占空比情况下,实现了较高逆变器电压输出,优化了电能质量,降低了准Z源网络的电容电压;其次,引入了简化PQ控制策略,实现了单位功率因数并网,电流谐波畸变率低;最后,经过Simulink软件和实验硬件研究,验证了新型准Z源三电平逆变器的优越性及其并网控制策略的有效性。

Aiming at the limitation that the traditional Z-source inverter has large starting impulse current insufficient boosting ability, and large capacitance voltage stress, a quasi-Z source neutral point clamped (NPC) three-level inverse topology is proposed. Firstly, the working principle of the proposed structure and the design of the quasi-Z source parameters are analyzed, the inverter can achieve higher voltage output at low shoot-through duty ratio, which optimizes the power quality and reduces quasi-Z source network capacitor voltage. Secondly, simplified PQ control strategy is introduced to achieve unit power factor grid connection, and current harmonic distortion rate is reduced. Finally, through the simulink software and experimental hardware research, the superiority of the new quasi-Z source three-level inverter and the effectiveness of the grid-connected control strategy are verified.