一种适用于变频器电源切换装置的合闸方法

A closing method for inverter power transfer device

在工业企业电力系统中,用变频器驱动电动机运行非常普遍。当变频器自身故障时,需要将电动机切换到由备用电源供电。目前一般采用残压合闸方式进行电源切换,然而由于变频器初始频率较低且该方法忽略了相位差的因素,所以在实际运行中往往会产生较大的冲击电流,造成电动机速断保护跳闸。本文提出一种适用于变频器电源切换装置的同期捕捉合闸方法,能在20~50Hz频率范围内实施电源切换。仿真表明,该合闸方法的冲击电流明显小于残压合闸方法的冲击电流,可以满足变频器电源切换的需求。

Inverter-driven motors are widely used in industrial power system.When inverter fails,motors must be transferred to standby power.Currently,residual voltage closing method is often used to implement power transfer.However,in practical operation,this method often produces large impulse current which makes motor’s instantaneous protection act,because the inverter initial frequency is very low and this method ignores phase difference.This paper develops a new delayed in-phase closing method that is suitable for inverter power transfer device.This method can implement transfer in the frequency range of 20~50Hz.Simulation proves this method produces less current than that of the residual voltage closing method,and it can meet the demand of inverter power transfer.