摘要
外特性是衡量逆变器性能的重要指标,代表了逆变器输出电压受负载的影响程度,性能优良的逆变器通常具有较硬的外特性,其空载到满载过程中输出电压的变化量较小。目前谐振控制器法是提高双环控制逆变器系统较为可靠的方法。但是该方案应用于400Hz中频逆变器时,会在空载或轻载下在低频段产生相移,造成相频曲线穿越??,同时因为中频逆变器的谐振控制器中心频率往往接近截止频率,谐振控制器的相位移设计不当会影响系统开环传递函数的相位裕度,造成系统的不稳定。本文通过对包含谐振控制器的三相四桥臂逆变器在全负载状态下的小信号建模,结合经典控制理论,分析了系统相频曲线低频段穿越??时稳定性判断条件,提出了一套应用于中频逆变器的谐振控制器设计依据。据此设计谐振控制器,逆变器在提高外特性的同时在全负载范围获得了良好的稳定性能和动态性能。最后通过仿真和实验验证了理论分析的正确性。
External characteristic is an important index for inverter performance. It represent that the output of inverter by effects of the load. External characteristic of inverter which has excellent performance is always strong, and output voltage changes little when load increase from empty to full. Until now resonant controller is efficient method to improve external characteristic of inverter. But after using resonant controller in 400 Hz medium frequency inverter, it will lead to phase frequency curve pass through-π by low frequency phase shift influence.Considering centre frequency of resonant controller is close to cut-off frequency of inverter, phase shift of resonant controller will cause inverter unstable by influence phase margin of system open-loop transfer function. This paper set up small signal modeling of three phase four bridge inverter working in full load, combines with principle of automatic control, analyze judgement of stability condition when phase frequency curve passes through-π, and offer design principle of resonant controller used in medium frequency inverter. The inverter gain excellent dynamic performance and steady state performance by using resonant controller design principle. Simulation and experiment results proved theoretical analysis is correct.
出处
《电工技术学报》
EI
CSCD
北大核心
2015年第3期94-102,共9页
Transactions of China Electrotechnical Society
关键词
三相四桥臂逆变器
谐振控制器
小信号建模
奈氏判据
自激振荡
Three bridge four leg inverter,resonant controller,small signal modeling,Nye's criterion,self excited oscillation
