Abstract:

The fast braking of resistant load and the falling speed control of the potential energy load are of great significance to improve the operation efficiency and the safety of motor drive equipments. In this paper, a method of constant current braking and dynamic adjustment of falling speed of lifiting objects for DC motor is proposed, in which the conventional energy consumption braking resistor is replaced by a power MOSFET and the equivalent resistance between its leakage and source can be adjusted by voltage control. Under the condition of no need to change the hardware, the double closed?loop control technology of current and speed is adopted to realize the requirements of the whole process constant current fast parking brake, the fast dropping of suspended objects and the falling speed continous adjustment control in the motor drive system. Theoretical analysis and experimental results show that the time for the parking brake and the time for the falling speed of the liftting object to reach stability are reduced respectively to 66.7% and 33.3% of the conventional braking method without chaning changing the hardware system, which effectively improves the dynamic working efficiency of the motor drive system and the flexibility of the control system.

Key words: Constant current braking, Fast braking, Falling speed regulation, DC motor control, Double closed loop control

摘要：

反抗性负载的快速制动与位能负载的落速控制对提高电机拖动装置的运行效率和安全具有重要意义。提出了一种由功率场效应管取代常规能耗制动电阻，通过压控方式在线调节其漏极与源极之间等效阻值实现直流电机全程恒流制动和吊物落速动态调节的方法。理论分析和实验结果表明，在无须改变硬件系统的条件下，该方法可将停车制动时间和吊物落速达到稳定的时间分别缩短为常规能耗制动方法的66.7%和33.3%，有效提高了电机拖动系统的动态工作效率以及控制系统的灵活性。

关键词: 恒流制动, 快速制动, 负载落速调节, 直流电机控制, 双闭环控制