摘要
为加大中压变频器出力,要求降低开关频率,这就带来了PWM波形谐波大的问题。解决上述问题的办法是采用同步且对称的优化PWM策略,介绍了CHM-PWM和SHE-PWM及其近似简化算法。优化PWM策略不能直接用于矢量控制等高性能系统,因为它在动态会造成PWM紊乱,系统过流。介绍了一种既能减小谐波又能快速响应的定子磁链轨迹跟踪控制方法,它基于优化PWM,又有在动态修正开关角的功能。为解决低开关频率对解耦的影响,出现了一种不同于矢量控制的基于磁链跟踪之新闭环调速系统。
To increase output power of medium voltage inverters, the switching frequency has to be decreased, that causes high harmonic problem. For solving the problem, it is better to adopt synchronized and symmetrical optimal PWM strategies. Two of them, CHM-PWM and SHE-PWM, and their approximate simplified algorithms,were introduced. The optimal strategies can not be used to high performance system directly, that will make system out-off work during transient. The system, stator flux trajectory control, which can both decrease harmonics and have fast response, was investigated, it is based on the optimal PWM and has the function of revising switching angles. For solving the cross-coupling problem caused by low switching frequen- cy a new closed-loop variable speed control system which is based on flux trajectory control and different from vector control was introduced.
出处
《电气传动》
北大核心
2009年第5期3-9,共7页
Electric Drive
关键词
低开关频率
优化PWM
磁链轨迹跟踪控制
闭环调速系统
low switching frequency
optimal PWM strategies
flux trajectory tracking control
closed-loopvariable speed control
