基于永磁开关的电容器组同步投切装置的研制

同步投切技术的实质是根据不同的负载特性,控制永磁开关在电压或电流最有利的相位下完成合闸或分闸,以主动消除开关过程中产生的过电压和涌流等电磁暂态效应。无功补偿电容器组的同步投切是当前同步开关技术的主要应用领域。笔者研制了一台以DSP F2812为核心的电容器组同步投切装置,利用锁相环电路实现同步采样,通过FFT算法准确提取参考信号的过零点,进而实现同步投切。在实验室对样机进行了测试,该投切装置的同步性能优于1 ms,能显著改善了电容器组投切过程的暂态效应。

Development of Synchronous Switching Device for Capacitor Bank Based on Permanent Magnet Switch

The essential of synchronous switching technology is to control switching action of a permanent magnet switch at optimum phase of voltage or current according to different load characteristics,thus to eliminate such electromagnetic transient effects as overvoltage and surge current.At present,the synchronous switching technology is mainly applied to synchronous switching of reactive power compensation capacitor bank.The authors developed a synchronous switching device for capacitor bank based on digital signal processor TMS320F2812.Synchronous switching is implemented with this device by using phase-locked loop to realize synchronous sampling,and by accurately extracting signal zero via FFT algorithm.This device is suitable for predicting the switching time with neural network,and can realize synchronous switching control.Experiment indicates that the synchronous switching time of the device is within 1 ms,and it can significantly weaken the transient effect in switching process of capacitor bank.