鉴频／鉴相组合分时切换的锁相环控制

传统的同步切换控制只能实现同步电动机在切换前后运行频率和相序的一致。由于切换前后交流电源的相位不同，往往会导致电机的电流和转矩发生较大的瞬时冲击性波动，对变频器、电网、电动机及其负载都会带来严重冲击。同时会缩短设备寿命，甚至会导致设备损坏。本文设计实现了一种将变频器作为锁相环路中的一个环节一压控振荡器的系统组成方案，提出了一种鉴频／鉴相组合分时切换的PLL控制方法。通过锁相环闭环自动调节变频器输出频率。与电网达到同频同相后。产生控制切换指令信号，使接触器发生切换，实现并网平滑切换的锁相同步控制。

The comparing of frequency/phase combination system by the switching way of time-sharing controlling

Traditional variable synchronization switching control systems only make frequency and phase sequence of synchronous motor identical switching around, as difference of AC power supply pha- ses switching around, often can result in instantaneous impact of fluctuations of motor current and torque, this can bring serious impact to transducer, electrified netting, motor and load, shorten equipment life at the same time, even leads to damage equipments. The paper designs one composition program which makes transducer as a tache of PLL; puts forward a control method about the comparing of frequency/phase combination system by the switching way of time-sharing. This system uses PLL close loop to make output frequency of transducer fulfill self-regulation, after output frequency and phase of transducer is the same as electrified netting, produces control instruction signals to make contactors switch, completes phase-locked synchronization control of variable grid connection smooth switching.