Device and method for controlling DC motor to lower roller shutter door at constant speed

Abstract

The invention discloses a control device of a DC motor for lowering a roller shutter door at constant speed, which comprises a rectifying module, a sampling comparison module, a switch module and a load module, wherein the switch module is serially connected with the load module and then parallelly connected to both ends of the DC motor; the input end of the rectifying module is parallel connected to both ends of the DC motor to rectify voltage signals at both end of the DC motor; and the sampling comparison module is connected with the output end of the rectifying module and he switch module and samples the rectified voltage signals, and the sampling comparison module sends out a control signal to the switch control according to a comparison result after a sampling value is compared with a setting value. The control device can block voltage at both ends of the DC motor within a certain range so as to lower the roller shutter door at constant speed, prolong the service life, and eliminate potential safety hazard. The invention also discloses a method for controlling the DC motor to lower the roller shutter door by using the device.

Description

[0001] technical field [0002] The invention relates to a DC motor for driving a rolling door to go up and down, in particular to a DC motor control device and method for making a rolling door go down at a constant speed. Background technique [0003] Due to its advantages of high safety performance and small footprint, the rolling shutter door is now used in more and more fields. The current rolling shutter door is generally driven by a DC motor, and its circuit connection is as follows: figure 1 As shown, the DC motor 1 (M) is connected to the power supply through the controller 2, and the controller 2 controls whether the DC motor 1 is started or not, and loads the power supply voltage in different directions, and then the DC motor 1 drives the upper end of the rolling door. The rotating shaft rotates in different directions to make the shutter door go up or down. [0004] When the rolling door moves upward, since the voltage at both ends of the DC motor 1 does not change...

AI Technical Summary

Problems solved by technology

[0004] When the rolling door moves upward, since the voltage at both ends of the DC motor 1 does not change much, the speed of dragging the rotating shaft is relatively stable, so that the rolling door can basically maintain a constant speed and a stable state when the rolling door moves upward; Slowly put down, as the door panel of the rolling shutter door goes down more and more, its center of gravity gradually moves down from the center of the rotating shaft, and the gravity it receives gradually increases, so it drives the rotating shaft to rotate faster and faster. At the same time, its gravitational potential energy is also transformed into The electric energy is supplied to the DC motor 1, at this time, the DC motor 1 is equivalent to a generator, and the voltage at both ends increases rapidly (it can be increased from 24V under normal conditions to more than 63V, which is related to factors such as the size of the door body mechanism), and the driving shaft rotates rapidly When the rolling door is lowered, the downward speed of the rolling door will become faster and faster due to the increase in acceleration until it is completely lowered; especially in some large shopping malls or garages, the weight of the rolling door is often very large, and the downward speed is even more amazing. At the moment of stopping, the lower end of the rolling door hits the ground heavily, which not only easily damages the structure of the rolling door body, the motor and the floor, but also shortens the service life of the DC motor 1 due to prolonged heating, and the downward speed of the rolling door is uncontrollable, which easily poses a threat to the human body ,There are security risks

[0005] In order to overcome the above-mentioned defects, someone now connects a load 30 in parallel at both ends of the DC motor 1, such as figure 2 As shown, the load 30 can shunt the current in the circuit, thereby reducing the voltage at both ends of the DC motor 1, reducing the output power of the DC motor 1, and driving the rotation speed of the rotating shaft to decrease, thereby reducing the downward speed of the rolling door; , connect the load 30 to the circuit, but since the DC motor 1 will only turn into a generator after the shutter door is lowered for a certain distance, it will reduce its working efficiency during normal operation; The current of the load 30 is very large, so it will consume a large amount of electric energy, and it is also working when the rolling door is in normal operation, resulting in a large amount of waste of electric energy, and the required load 30 must have enough power to be actually used, otherwise, The load 30 will be damaged due to overload, which further consumes electric energy; the high-power load 30 has high cost, which increases the manufacturing cost of the DC motor 1, and at the same time, the load 30 generates a large amount of heat, which makes the local temperature too high and affects the service life of other components.

Images