中高压软启动控制器的设计

直接启动电动机会产生很强的冲击电流,降低了电动机的使用寿命,对电网也会造成很大的冲击。设计一种限流PI调节降压式软启动,该软启动以TMS320F28335为控制核心,通过在同步信号作用下,采集电动机启动时电流、电压信号,对晶闸管触发角移相的控制实现电动机启动电压和电流的调节,电动机启动过程中的参数可以根据电动机不同负载特性来设置,启动过程设计了过压、过流检测电路和电动机保护回路,可以确保电动机安全平稳的启动。对该设计方案进行仿真和实验验证,仿真和实验表明在相同负载下,直接启动方式下电动机启动时会产生5~7倍额定电流强度的启动电流,而在软启动方式下减小到2倍左右,验证了本设计能显著地降低电机启动电流。

Design of Medium and High Voltage Soft Start Controller

Direct start of electric power will produce a strong impact current,which will reduce the service life of the motor and will also have a great impact on the power grid.In this paper,a kind of current limiting PI regulating pressure-relief soft start is designed.The soft start takes TMS320F28335 as the control core,and it collectes the current and voltage signals at the start of the motor under the action of synchronous signals.The control of the trigger angle conduction and shift direction of the thyristor realizes the adjustment of the three-phase start-up voltage and current of the motor.The parameters during the start-up process of the motor can be set according to the different load characteristics of the motor.The circuit of over-voltage and overflow detection and motor protection circuit are designed to ensure the safe and steady start of motor during the start-up process.The simulation and experimental verification of the design project show that under the same load,the start-up current of 5-7 times the rated current intensity will be generated when the motor is started under the same load,and it will be reduced to about 2 times in the soft start-up mode.It is proved that the design can significantly reduce the electric current and the voltage of the motor.