A zero-risk motor runaway control method

Abstract

This invention discloses a zero-risk motor overspeed control method applicable to situations where the motor rotates in a combination of clockwise and counterclockwise directions. The method involves connecting the normally closed contact of a microswitch in series with the DO input signal of the motor driver's power supply control circuit via an electrical connection line. The microswitch detects the cable winding state, and automatically disconnects the normally closed contact when an abnormality occurs, thereby cutting off power to the motor. This invention utilizes a commercially available, low-value microswitch to detect the cable winding state, achieving a self-power-off function for the motor. It is simple, low-value, and provides 100% protection for the product.

Description

Technical Field

[0001] This invention belongs to the field of test control, specifically relating to a zero-risk motor overrun control method. Background Technology

[0002] In aerospace, security, medical, and power industries, electric motors are widely used as a power source to drive loads. In some testing scenarios, due to the fixed connection of the rotor load leads, the motor cannot rotate continuously in the same direction. It can only be controlled to rotate clockwise and counterclockwise in combination, provided the lead length allows. For example, when testing the electrical characteristics of a conductive slip ring during rotation, each lead of the stator and rotor is usually connected to the same fixed test fixture. Because of the connecting wires, the motor cannot rotate continuously in the same direction while driving the conductive slip ring rotor. A safe rotation control method is n (n≧1) turns clockwise / counterclockwise, then n turns counterclockwise / clockwise. To ensure this rotational characteristic, common practices include setting a manual emergency brake switch and adding a watchdog timer to the motor's rotation control software to prevent motor overshoot. However, these methods cannot completely eliminate the risk of overshoot. If the software malfunctions and there is no emergency braking, the rotor leads may still be stressed, potentially damaging the product.

[0003] To reduce the risk of a runaway vehicle to zero, the motor needs to be able to automatically recognize the runaway state. This requires the power source itself to have hardware protection measures so that manual emergency braking is not needed in case of an accident. A simple and low-cost method is to add a limit block. However, since the motor rotates at least once in the same direction, i.e., the rotation angle is at least 360 degrees, this is problematic. 0 Therefore, limit blocks are not suitable. A more complex approach is to add position detection hardware to provide real-time feedback on the motor's status and implement real-time protection. However, this method requires replacing or modifying the existing motor due to the addition of new components, and it also increases weight, size, and hardware and software costs. Therefore, if a zero-risk flying car control method can be made both low-cost and simple, it would have great application potential. Summary of the Invention

[0004] The purpose of this invention is to provide a low-cost, simple, and zero-risk motor overrun control method applicable to situations where the motor rotates in a combination of clockwise and counterclockwise directions.

[0005] To achieve the objective of this invention, a zero-risk motor-driven overrunning control method is provided, and the technical solution is as follows:

[0006] On the input control signal DO link of the motor driver power supply control circuit, the normally closed contact of the micro switch is connected in series with the control signal DO input terminal of the motor driver power supply control circuit through an electrical connection line. The micro switch is used to detect the winding state of the pull wire. When an abnormality occurs, the normally closed contact of the micro switch is automatically opened, thereby cutting off the power to the motor.

[0007] Furthermore, the stress-sensing end of the micro switch is connected to one end of a pull wire, and the other end of the pull wire is connected to the motor rotor, motor load, or motor steering shaft. The length of the pull wire is designed to allow the motor to rotate more than n+0.5 revolutions normally. When a motor overrun occurs, the pull wire will immediately generate a pulling force on the sensing end of the micro switch.

[0008] Furthermore, a detection circuit for the control signal DO and a voice / buzzer alarm circuit are added to the microswitch.

[0009] Furthermore, the micro switch is mounted on the motor or at a fixed position near the motor.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] This invention provides a low-cost, simple, zero-risk motor overrun control method. Starting from the motor power supply control, it utilizes the currently mature low-cost microswitches on the market to detect the winding state of the pull wire, thereby realizing the motor's self-power-off function. At the same time, it notifies the staff of the unexpected situation through voice or buzzer alarm, ultimately achieving the goal of zero overrun risk and thus achieving 100% protection for the product. Attached Figure Description

[0012] Figure 1 A schematic diagram of the working principle of the power supply control circuit for the original motor drive is shown.

[0013] Figure 2 A schematic diagram illustrating the working principle of the power supply control circuit for the improved motor drive according to an embodiment of the present invention is shown. Detailed Implementation

[0014] The specific embodiments of the present invention will be described in detail below.

[0015] The working principle of the power supply control circuit for the original motor drive is as follows: Figure 1 As shown, the DO signal output from the board enters the motor driver power supply control circuit after passing through the manual control switch. When the DO signal is valid and the manual switch is closed simultaneously, the controlled DC power supply voltage is output normally to the motor driver. The motor driver outputs corresponding multi-phase AC power to the motor according to different control signals, thereby controlling the motor rotation.

[0016] The working principle of the power supply control circuit for the original motor drive is as follows: Figure 1As shown, the control signal DO output from the board enters the motor driver power supply control circuit after passing through the manual control switch. When the control signal DO is valid and the manual switch is closed simultaneously, the controlled DC power supply voltage is output normally to the motor driver. The motor driver outputs corresponding multi-phase AC power to the motor according to different control signals, thereby controlling the motor rotation. As long as the control signal DO is valid and the manual switch is closed simultaneously, the motor will rotate. In case of accidental runaway, the motor can only be stopped by manually disconnecting the manual switch in an emergency. This method requires personnel to be on duty at all times.

[0017] The present invention provides a zero-risk motor overrun control method, the working principle of which is as follows: Figure 2 As shown, in the input control signal DO link of the motor driver power supply control circuit, the normally closed contact of a microswitch is connected in series to the DO input terminal of the motor driver power supply control circuit. The microswitch detects the winding state of the pull wire, and automatically disconnects the normally closed contact of the microswitch when an abnormality occurs, thereby cutting off power to the motor. The stress-sensing end of the microswitch is connected to one end of the pull wire, and the other end of the pull wire is connected to the motor rotor, motor load, or motor steering shaft. The length of the pull wire should be designed such that the motor rotates at least n+0.5 revolutions to generate tension on the pull wire. The pull wire will immediately generate tension on the sensing end of the microswitch, causing the microswitch to actuate and the normally closed contact to open.

[0018] In one specific embodiment, the microswitch can be installed on the motor or at a fixed position near the motor. A pull cable of a certain length reliably connects the microswitch to the motor load, ensuring that the pull cable and the motor load rotate in the same direction. The length of the pull cable is determined to ensure that the motor can maintain normal n+0.5 revolutions in both clockwise and counterclockwise directions, while also ensuring that the microswitch can sense the motor load in advance after a runaway event, thus achieving 100% protection for the motor load.

[0019] In one specific embodiment, the micro switch is mounted on the motor, and the two ends of the normally closed contact of the micro switch are connected in series through its electrical connection wire. Figure 2 The power supply control circuit of the motor drive is shown. The micro switch and slip ring connection device are reliably connected by a pull wire. The pull wire rotates in the same way as the motor. The length of the pull wire must ensure that the motor can maintain normal n+0.5 revolutions in both clockwise and counterclockwise directions, and also ensure that the micro switch can sense in advance before the motor steering shaft is subjected to force after the motor overruns, and the normally closed contact opens, thereby cutting off the power supply to the motor and achieving 100% protection for the conductive slip ring.

[0020] In one specific embodiment, a detection circuit for the control signal DO and a voice / buzzer alarm circuit are added to the micro switch to provide real-time protection for the motor and achieve comprehensive prevention of accidental runaway.

Claims

1. A zero risk electric motor runaway control method, characterized by, The normally closed point of the micro switch is connected to the input control signal DO link of the motor driver power supply control circuit through an electric connection line, the normally closed point of the micro switch is connected to the control signal DO input end of the motor driver power supply control circuit, the micro switch is used to detect the pulling ring winding state, and the normally closed point of the micro switch is automatically disconnected when an abnormal situation occurs, so that the motor is powered off.

2. A zero risk electric machine runaway control method according to claim 1, characterized in that, The stress sensing end of the micro switch is connected to one end of the pull wire, the other end of the pull wire is connected to the motor rotor or the motor load or the motor steering shaft, and the length of the pull wire is designed to be more than n+0.5 turns in normal motor rotation. When the motor flywheel fault occurs, the pull wire will immediately generate a pulling force on the sensing end of the micro switch.

3. A zero risk electric machine runaway control method according to claim 1 or 2, characterized in that, A detection circuit and a voice / buzzing alarm circuit of the control signal DO are added to the micro switch.

4. The zero-risk electric machine runaway control method of claim 1, wherein, The micro switch is installed on the motor or in a fixed position near the motor.

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