Double-closed-loop feedback-control module

Abstract

The invention relates to a double-closed-loop feedback-control module, wherein two closed-loop control loops are formed in the starting process and the holding stage of a contactor to directly and accurately control the coil current of the contactor, so that the optimizing control for the integral action characteristic of the contactor can be carried out, and the integral performance index of the contactor is comprehensively improved. The double-closed-loop feedback-control module has low hardware cost, the voltage-adjusting rate of a system can be improved, the transient response speed of the system is increased, and the stability of the system is enhanced.

Description

technical field [0001] The invention relates to the field of intelligent control of equipment, in particular to a double-closed-loop feedback control module of an AC contactor. Background technique [0002] The intelligent control and design technology of low-voltage electrical appliances has made great progress in recent years at home and abroad, and new design ideas continue to emerge. Taking the electromagnetic AC and DC contactors widely used in the system as an example, new products have emerged continuously in recent years. With the construction of smart grid, various performance indicators such as intelligence and communication of electrical products in the primary circuit, secondary circuit, and detection and monitoring circuit have been widely valued. [0003] The current main control ideas and control methods of intelligent AC contactors are as follows: [0004] (1) Control scheme for high-voltage DC starting and low-voltage DC holding [0005] For the tradi...

AI Technical Summary

Problems solved by technology

During the control process, the switching tube of the starting circuit will bear a huge current impact, especially for large-capacity contactors (such as AC contactors above 630A), the control is very difficult

[0009] Secondly, it is necessary to monitor the current change law in the contactor coil in real time, so as to realize the optimal control of the whole process, which is difficult to realize by using the voltage control scheme.

[0010] Third, in the high-voltage starting and low-voltage maintenance scheme, two power electronic switches are required to perform high-low level conversion, and the voltage and current stress of the high-voltage starting power electronic switch increases rapidly with the increase of the contactor capacity, and the cost also increases rapidly; When holding, the auxiliary power supply is required to provide the coil holding voltage, and the capacity of the auxiliary power supply also increases with the increase of the capacity of the contactor, and the cost of the protection of the switch tube and the control circuit also increases

[0016] However, the single closed-loop control scheme with current feedback is still a voltage-type PWM control scheme. By adjusting the PWM duty cycle to change the effective voltage of the coil, the overall response speed is still relatively slow, and the control effect needs to be improved.

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