A control method and device for a permanent magnet operating mechanism of a pwm monostable vacuum circuit breaker

Abstract

The invention relates to a PWM (pulse width modulation) based monostable vacuum circuit breaker permanent magnetic operating mechanism control method and a device for implementing the same. Adjustments are performed through three closed loops including a contact position loop, a contact speed loop and a mechanism coil current loop. Exciting current is adjusted by the contact position loop according to the contact position. A PWM duty cycle is adjusted by the contact speed loop according to feedback signals of the contact position loop. Switch-on-off operations are controlled by the mechanism coil current in real-time according to the exciting current and the PWM duty cycle. A fuzzy PID (proportional integral derivative) controller is adopted in the contact position loop and the contact speed loop. PI (priority interrupt) control is adopted in the mechanism coil current loop. The PWM based monostable vacuum circuit breaker permanent magnetic operating mechanism control method has the advantages that synchronous operation capacity and reliability of the mechanism are improved; the main coil current detection and the auxiliary contact travel detection are cooperated with each other; and a pulse width modulation technology is adopted in operations of a circuit breaker, closed-loop control of contact movement features in the switch-on-off operations of the circuit breaker is realized through changing the coil current, stability of operation time is guaranteed, and accuracy of switch-on-off phases is improved.

Description

Technical field [0001] The invention relates to the field of electrical appliance automation control, and in particular to a method and a device for controlling a permanent magnet operating mechanism of a monostable vacuum circuit breaker based on PWM. Background technique [0002] The operating phase of the traditional switch is random, and it is easy to generate a large inrush current and a high induced overvoltage when the power system is switched on and off, which leads to a reduction in the service life of the switch device and the power supply quality of the power system. Therefore, studying the intelligent control technology of the circuit breaker can not only ensure the reliability, stability and improve the power quality of the power supply, but also have important meanings to effectively improve the production efficiency of enterprises and the service life of equipment. [0003] In principle, the synchronous closing and closing control technology can effectively weaken th...

AI Technical Summary

Problems solved by technology

The current traditional action time compensation method is that the control system detects various influencing factors online and calculates the value of the action time change caused by them to determine the moment when the action signal is issued. This method can only adjust the opening and closing time The error is controlled at ±2ms, and the opening and closing phase error reaches ±36°. However, the premise of the practical application of synchronous closing and closing control technology in the smart grid is that the closing time error must be within ±0.5ms, so that it is possible to be more accurate Therefore, the current control system has a low ability to suppress inrush current and overvoltage in actual operation.

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