Protection device for preventing dry rotation of motor

Abstract

The invention discloses a protection device for preventing dry rotation of a motor. The protection device comprises the motor and a protection loop. The motor comprises a control loop which controls operation of the motor and receives sampling signals of the motor. The protection loop is electrically connected with a control loop of the motor and comprises a signal sampling unit, a signal judging unit and a switch. The signal sampling unit is used for receiving and sampling a sampling signal so as to output a first sampling signal and a second sampling signal; the signal judgment unit is electrically connected with the signal sampling unit and used for receiving the first sampling signal and the second sampling signal to judge whether the motor rotates in a dry mode or not and outputting a decision signal when the motor rotates in the dry mode. The switch is electrically connected with the signal judgment unit and the control loop and receives the decision signal to output the driving signal to the control loop, and the control loop receives the driving signal to close the motor or reduce the rotating speed of the motor.

Description

Technical Field

[0001] The present invention relates to a protection device for preventing a motor from dry-running, and more particularly to a protection device capable of actively detecting the dry-running of a motor. Background Art

[0002] With the rapid advancement of technology, the computing power of computers and servers has greatly improved. As a result, the heat generated by chips has become increasingly high. Conventional air cooling is no longer sufficient, and liquid cooling (also known as water cooling) has begun to be widely used for high-energy-consuming chips.

[0003] Liquid cooling uses a liquid (such as deionized water or a specialized coolant) as a heat transfer medium, transferring heat through cooling pipes to an external heat sink. However, after a period of use, the water pump (or motor) may run dry (also known as idling). Since the pump requires liquid as a lubricant, idling causes frictional wear. Short dry runs are generally harmless, but prolonged dry runs (which vary from pump to pump and can range from one minute, two minutes, or five minutes) can damage the computer or server hardware.

[0004] Currently, water pump dry-run detection typically involves engineers checking the liquid cooling system's monitoring software to see if the speed, temperature, or flow rate are normal, or by hearing unusual noises from a computer or server. These types of detection require engineers to make their own judgments. If engineers fail to detect a dry-run pump, it can easily lead to pump failure and even damage to the computer or server hardware.

[0005] In view of the above shortcomings, the inventors of this case and related manufacturers engaged in this industry are eager to study and improve the direction. Summary of the Invention

[0006] The main purpose of the present invention is to provide a protection device for preventing a motor from running dry, without requiring an engineer to monitor the motor at all times to check whether the motor is running dry.

[0007] In addition, another object of the present invention is to provide a protection device for preventing a motor from dry-running, and the protection device can avoid the occurrence of a misjudgment of a motor dry-running.

[0008] In order to achieve the above-mentioned purpose and effect, the present invention provides a protection device for preventing a motor from running dry, which includes a motor and a protection circuit. The motor includes a control circuit, which controls the operation of the motor and receives a sampling signal of the motor. The protection circuit is electrically connected to the control circuit of the motor and includes a signal sampling unit, a signal judgment unit and a switch. The signal sampling unit is used to receive and sample the sampling signal to output a first sampling signal and a second sampling signal; the signal judgment unit is electrically connected to the signal sampling unit, and is used to receive the first sampling signal and the second sampling signal to determine whether the motor is running dry, and outputs a decision signal when the motor is running dry; the switch is electrically connected to the signal judgment unit and the control circuit, and receives the decision signal to output a drive signal to the control circuit, and the control circuit receives the drive signal to turn off the motor or reduce the speed of the motor.

[0009] In order to enable those skilled in the art to understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific embodiments and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram of a protection device for preventing a motor from dry-running according to the present invention;

[0011] Figure 2 A method flow chart of a protection method for preventing a motor from dry-running according to the present invention; and

[0012] Figure 3A and Figure 3B The waveform diagram is for actually testing the protection device for preventing motor dry rotation of the present invention.

[0013] Explanation of the accompanying symbols: 10-protection device; 12-motor; 14-protection circuit; 122-control circuit; 142-signal sampling unit; 144-signal judgment unit; 146-switch; 1442-memory module; 1444-comparison module; 1446-counting module; S201~S206-steps; 302-detection time interval; 304-phase current frequency. DETAILED DESCRIPTION

[0014] The above-mentioned objectives and structural and functional characteristics of the present invention will be described with reference to the preferred embodiments shown in the accompanying drawings.

[0015] Figure 1 FIG. 1 is a schematic diagram of a protection device for preventing a motor from dry-running according to the present invention. Figure 1As shown, the protection device 10 for preventing the motor from running dry of the present invention includes a motor 12 and a protection circuit 14. The motor 12 includes a control circuit 122, and the control circuit 122 is used to receive the sampling signal output by the motor 12 and to control the operation and switching of the motor 12. The motor 12 of the present invention is preferably a motor used for liquid cooling, but is not limited thereto. In a preferred embodiment of the present invention, the control circuit 122 and / or the protection circuit 14 can be composed of a microcontroller (Micro Controller Unit, MCU), but in different embodiments, the control circuit 122 and the protection circuit 14 can also be composed of multiple circuit elements, which is not limited thereto. The control circuit 122 of the motor 12 is electrically connected to the protection circuit 14, and the control circuit 122 outputs the sampling signal of the motor 12 to the protection circuit 14. The protection circuit 14 determines whether the motor 12 is in a dry running state based on the sampling signal. When the motor 12 runs dry for more than a certain time, the protection circuit 14 outputs a control signal to the control circuit 122 of the motor 12. The control circuit 122 stops the motor 12 according to the control signal, or reduces the speed of the motor 12 according to the control signal.

[0016] Specifically, the protection circuit 14 includes a signal sampling unit 142, a signal determination unit 144, and a switch 146. The signal sampling unit 142 is electrically connected to the control circuit 122 of the motor 12 and the signal determination unit 144. The signal sampling unit 142 is configured to receive a sampling signal output from the control circuit 122. The sampling signal of the present invention is an analog signal of the motor 12 (e.g., a motor current signal, etc.). The signal sampling unit 142 performs signal sampling processing on the received sampling signal and then outputs the processed signal to the signal determination unit 144. It should be noted that the signal sampling processing performed by the signal sampling unit 142 on the received sampling signal may involve analog-to-digital conversion of the signal. Converting a signal from an analog signal in the continuous time domain to a discrete signal in the discrete time domain is well known to those skilled in the art and will not be elaborated upon herein.

[0017] The signal determination unit 144 is electrically connected to the switch 146, and the switch 146 is electrically connected to the motor 12. The signal determination unit 144 receives the sampling signal output from the signal sampling unit 142 and determines whether the dry-run condition of the motor 12 is met based on the received sampling signal, thereby determining whether to trigger the protection mechanism. Furthermore, the signal sampling unit 142 samples or calculates the received sampling signal to separate it into a first sampling signal and a second sampling signal. The first sampling signal is the motor phase current frequency, and the second sampling signal is the motor average current. The signal determination unit 144 includes a memory module 1442, a comparison module 1444, and a counting module 1446. The memory module 1442 stores a first sampling threshold and a second sampling threshold. The comparison module 1444 is electrically connected to the memory module 1442. The counting module 1446 is electrically connected to the comparison module 1444. The comparison module 1444 compares the first sampling signal with the first sampling threshold and the second sampling signal with the second sampling threshold, respectively. Then, the counting module 1446 counts the number of times the abnormal state of the motor 1212 occurs according to the comparison result of the comparison module 1444. When the comparison module 1444 compares that the motor 12 may be running dry, the counting module 1446 will count by 1. When the counting module 1446 accumulates to a certain value within a certain period of time, the signal judgment unit 144 determines that the motor 12 is in a dry-running state and outputs a judgment signal to the switch 146 to decide whether to activate the switch 146 to turn off the motor 12 or reduce the speed of the motor 12.

[0018] Specifically, the first sampling signal represents the phase current frequency of motor 12, the first sampling threshold represents the phase current frequency threshold, the second sampling signal represents the average current of motor 12, and the second sampling threshold represents the average current threshold. For example, the first sampling threshold represents the phase current frequency threshold of 210 Hz, and the second sampling threshold represents the average current threshold of 1.9 A. When the first sampling signal (phase current frequency) of motor 12 is less than 210 Hz and the second sampling signal (average current) is greater than 1.9 A, comparison module 1444 records an abnormality and increments its count by 1. If the number of abnormality occurrences recorded by comparison module 1444 exceeds a predetermined value within a time interval (e.g., 10 seconds or 11 seconds), comparison module 1444 outputs a determination signal to switch 146, which in turn outputs a drive signal to control circuit 122 to shut down or decelerate motor 12. In addition, it should be noted that the values ​​of the first sampling threshold and the second sampling threshold in the present invention are not limited to the above-mentioned values. There are also detection cycles and abnormality count constants. In different embodiments, different motors 12 may have different thresholds, detection cycles, and abnormality count constants.

[0019] The switch 146 of the present invention is preferably constructed from a metal-oxide-semiconductor field-effect transistor (MOSFET). How to activate the switch 146 based on the magnitude of the signal is well known to those skilled in the art and will not be further described here. The motor dry-run protection device 10 described above can automatically detect whether the motor 12 is in a dry-run state. If the abnormality occurs several times within a certain time interval, the protection circuit 14 of the present invention can determine that the motor 12 is in an idling state and activate the switch 146 to shut down the motor 12 or reduce its speed. The motor 12 can then be restarted after another time interval.

[0020] Furthermore, it should be noted that in the above-described embodiment, two sampling signals are used because an abnormal sampling signal output by motor 12 may simply be caused by unstable current in motor 12, which may be a sudden condition. To prevent misjudgment by the protection circuit 14 of the present invention, the protection mechanism is activated to stop or reduce the speed of motor 12 only when multiple abnormal conditions are detected in the sampling signal. The motor dry-run protection device 10 of the present invention can effectively prevent the motor 12 from dry-running, eliminating the need for engineers to constantly check whether the motor 12 is dry-running and preventing the motor dry-run protection device 10 from misjudging dry-running.

[0021] Figure 2 This is a flow chart of the method for preventing motor dry-rotation protection of the present invention, as shown in FIG. Figure 2 As shown, and reference Figure 1 Component label, in step S201, the motor dry-run protection mechanism is activated. In the present invention, the motor dry-run protection mechanism does not immediately begin detecting abnormalities upon startup of the motor 12. This is because the sampling signal of the motor 12 is unstable when it is first started. If abnormality detection is initiated at this time, it is easy to cause a false positive. Therefore, the motor dry-run protection mechanism of the present invention is not activated until a time T has passed. For example, time T can be 2 seconds or 3 seconds, but this is not limited here.

[0022] In step S202, a determination is made as to whether the first sampling signal is below a first signal threshold and whether the second sampling signal is above a second signal threshold. If so, the process proceeds to step S203; if not, the process proceeds to step S204. In the process of determining motor dry-running of the present invention, the signal sampling unit 142 extracts a first sampling signal and a second sampling signal from the sampling signal. The first sampling signal represents the phase current frequency, and the second sampling signal represents the average current. When the comparison module 1444 determines that the phase current frequency is below the first signal threshold (e.g., 210 Hz) and the average current is above the second signal threshold (e.g., 1.9 A), the process proceeds to step S203. If the phase current frequency is above the first signal threshold or the average current is below the second signal threshold, meaning that one of the abnormal conditions in step S202 was not detected, the process proceeds to step S204. To prevent misjudgments in the motor dry-run protection device of the present invention, both the first sampling signal and the second sampling signal are first checked to see if an abnormality is present before proceeding to the next step of determining whether motor dry-running has occurred.

[0023] In step S203, the accumulated value of the counting module 1446 is checked to see if it is less than a predetermined value. If so, the process proceeds to step S205; if not, the process proceeds to step S206. In step S203, a further determination is made as to whether the total counted by the counting module 1446 exceeds a predetermined value. For example, if the total count is 10,000, the first sampling signal is checked every millisecond to see if both the first sampling signal and the second sampling signal exceed the second signal threshold. Each time both the first sampling signal and the second sampling signal exceed the first signal threshold, the counting module 1446 increments by 1. In step S203, the accumulated count of the counting module 1446 is determined to be less than 10,000. If the accumulated count is less than 10,000, it indicates that the motor has not yet reached the threshold for determining that the motor has run dry for an extended period of time. Step S205 is then entered, and the counting module 1446 increments by 1. If the accumulated count is greater than 10,000, the process proceeds to step S206, indicating that motor 12 has entered or is already in the dry-run protection state. Motor 12 is stopped or its speed is decreasing, and counting module 1446 does not need to perform any increment or decrement operations. After completing step S205 or step S206, the process returns to step S202 to begin the next dry-run detection step.

[0024] In step S204, the accumulated value of counting module 1446 is determined to be greater than 0. If so, the process proceeds to step S207; if not, the process returns to step S202. If the phase current frequency is greater than the first signal threshold or the average current is less than the second signal threshold, that is, if one of the abnormal conditions detected in step S202 is not detected, it indicates that motor 12 is not in a dry-run state. If the accumulated count value of counting module 1446 exceeds a certain value (e.g., 10,000), in step S207, counting module 1446 decrements the count by 1, indicating that motor 12 has returned to normal operation from a dry-run state. After decrementing the count by 1, the process returns to step S202 to begin the next dry-run detection. Conversely, if the accumulated count value of counting module 1446 does not exceed 10,000, counting module 1446 does not perform any counting operation. After completing the check of the accumulated count value in step S204, the process returns to step S202 to begin the next dry-run detection.

[0025] Figure 3A and Figure 3B This is a waveform diagram of the protection device for preventing motor dry rotation according to the present invention. Figure 3A As shown, the detection time interval 302 of the motor dry-run protection device of the present invention is 10 seconds, and the time interval can be changed according to different motors or user needs. Figure 3B As shown, at 1.4 seconds, the motor phase current frequency 304 is 222 Hz, which is less than the first sampling threshold (210 Hz ± 50 Hz), indicating that motor 12 may be running dry. The above-described motor dry-run protection device and method can effectively detect motor dry-run conditions and prevent false motor dry-run detection. The motor dry-run protection device and method of the present invention can determine whether a motor dry-run condition has occurred without requiring engineers to frequently monitor the motor's condition.

[0026] The above describes the implementation of the present invention through specific embodiments. Those skilled in the art with ordinary knowledge in the relevant technical field can easily understand other advantages and effects of the present invention from the contents disclosed in the specification of the present invention.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any other equivalent changes or modifications that do not depart from the spirit disclosed by the present invention should be included in the following protection scope.

Claims

1. A protection device for preventing a motor from running dry, characterized in that: Include: a motor comprising a control loop for controlling the operation of the motor and receiving a sampling signal from the motor; and a protection circuit electrically connected to the control circuit of the motor and comprising: a signal sampling unit for receiving and sampling the sampling signal to output a first sampling signal and a second sampling signal; a signal determination unit electrically connected to the signal sampling unit, configured to receive the first sampling signal and the second sampling signal to determine whether the motor is running dry, and output a determination signal when the motor is running dry; and A switch is electrically connected to the signal determination unit and the control circuit, receives the decision signal and outputs a driving signal to the control circuit, and the control circuit receives the driving signal to turn off the motor or reduce the speed of the motor.

2. The protection device for preventing motor dry-running according to claim 1, characterized in that: The signal judgment unit includes: a memory module for storing a first sampling threshold and a second sampling threshold; a comparison module electrically connected to the memory module, for comparing the first sampling signal with the first sampling threshold and the second sampling signal with the second sampling threshold to output a comparison result; and A counting module is electrically connected to the comparison module, and counts the number of times the abnormal state of the motor occurs according to the comparison result of the comparison module.

3. The protection device for preventing motor dry-running according to claim 2, characterized in that: The first sampling signal is a phase current frequency, and the second sampling signal is an average current.

4. The protection device for preventing motor dry-running according to claim 3, characterized in that: When the comparison module compares the first sampling signal and the second sampling signal and finds that they exceed the first sampling threshold and the second sampling threshold respectively, the counting module increases by 1.

5. The protection device for preventing motor dry-running according to claim 4, characterized in that: When the counting module counts to a certain value within a time interval, the signal determination unit determines that the motor is in a dry-run state, and the signal determination unit outputs the determination signal to the switch.

6. The protection device for preventing motor dry-running according to claim 4, characterized in that: When the comparison module determines that the first sampling signal does not exceed the first sampling threshold or the second sampling signal does not exceed the second sampling threshold, the counting module does not add 1.

7. The protection device for preventing motor dry-running according to claim 4, characterized in that: The motor is a water-cooled heat sink.

8. The protection device for preventing motor dry-running according to claim 1, characterized in that: The protection circuit is composed of a microcontroller.

9. The protection device for preventing motor dry-running according to claim 1, characterized in that: The switch is a switch composed of a MOSFET.

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