Motor open-phase protection method and device, storage medium, controller and program product

Abstract

The invention provides a motor open-phase protection method and device, a storage medium, a controller and a program product, and the method comprises the steps: judging whether a motor is in a load state or a no-load state or not according to the size of the output current of the motor; if the motor is judged to be in the no-load state, not judging whether the motor is open in phase or not; if it is judged that the motor is in the load state, whether the motor is in phase loss or not is judged according to the magnitude of the output current of the motor; and if the motor is judged to be in the open-phase state, controlling the motor to stop so as to carry out open-phase protection on the motor. According to the scheme provided by the invention, open-phase judgment and protection are not carried out in a no-load state, and no-load open-phase false triggering is avoided.

Description

Technical Field

[0001] The present invention relates to the field of control, and in particular to a motor phase loss protection method, device, storage medium, controller and program product. Background Art

[0002] At present, in the application of sensorless vector control of permanent magnet synchronous motor, output phase loss protection has become an important research object. Its main function is to effectively identify when the motor encounters output phase loss during the operation of the motor, and trigger the phase loss protection to stop the motor operation, thereby protecting the motor.

[0003] The phase loss protection in the related technology includes: 1. By collecting the magnitude of the three-phase current output by the motor, if one of the phase currents approaches zero, it is determined that a phase loss occurs and the motor is protected; 2. By collecting the current output by the motor, the difference between the two-phase current is compared with the third-phase current to determine whether there is a phase loss. The above two control methods both determine whether there is a phase loss by collecting the magnitude of the phase current. However, in actual applications, some motors have relatively small phase currents under no-load conditions, which will falsely report a phase loss fault, or the sampled current has abnormal fluctuations under high temperature conditions, which will also cause the motor to falsely report a phase loss fault. The reliability of these solutions is poor. Summary of the invention

[0004] The main purpose of the present invention is to overcome the defects of the above-mentioned related technologies and provide a motor phase loss protection method, device, storage medium, controller and program product to solve the problem of false reporting of motor phase loss fault under no-load conditions or high temperature conditions in the related technologies.

[0005] On one hand, the present invention provides a motor phase-loss protection method, comprising: judging whether the motor is in a load state or a no-load state according to the output current of the motor; if the motor is judged to be in a no-load state, not judging whether the motor is phase-loss; if the motor is judged to be in a load state, judging whether the motor is phase-loss according to the output current of the motor; if the motor is judged to be phase-loss, controlling the motor to stop so as to perform phase-loss protection on the motor.

[0006] Optionally, judging whether the motor is in a load state or a no-load state based on the output current of the motor includes: judging whether the output current of the motor is greater than zero and less than or equal to a first preset output current threshold; if it is judged that the output current of the motor is greater than zero and less than or equal to the first preset output current threshold, determining that the motor is in a load state; if it is judged that the output current of the motor is equal to zero or greater than the first preset output current threshold, determining that the motor is in a no-load state.

[0007] Optionally, the first preset output current threshold is obtained by: detecting the average value of the three-phase output current at the highest speed of the motor in a no-load state and the average value of the three-phase output current at the lowest speed of the motor in a loaded state; determining the first preset output current threshold according to the average value of the three-phase output current at the highest speed of the no-load state and the average value of the three-phase output current at the lowest speed of the loaded state; wherein the first preset output current threshold is equal to the sum of the average value of the three-phase output current at the highest speed of the motor in a no-load state and the preset current value, and the first preset output current threshold is less than the average value of the three-phase output current at the lowest speed of the motor in a loaded state.

[0008] Optionally, judging whether the motor is lacking a phase is based on the output current of the motor, including: judging whether the output current of the motor is less than a second preset output current threshold and lasts for a first preset time; if it is judged that the output current of the motor is less than the second preset output current threshold and lasts for the first preset time, controlling the motor to stop for a second preset time and then restart, and re-judging whether the motor is lacking a phase, and so on; when it is judged that the output current of the motor is less than the second preset output current threshold and lasts for the first preset time for N consecutive times, it is determined that the motor is lacking a phase.

[0009] Optionally, the second preset output current threshold is obtained by respectively detecting the output currents of the other two phases when one of the three phases of the motor is disconnected at the lowest speed in the load state, and taking the average value of the detected three-phase output current as the second preset output current threshold.

[0010] On the other hand, the present invention provides a motor phase-loss protection device, comprising: a first judgment unit, used to judge whether the motor is in a load state or a no-load state according to the output current of the motor; a second judgment unit, used to not judge whether the motor is phase-loss if the first judgment unit judges that the motor is in a no-load state, and to judge whether the motor is phase-loss according to the output current of the motor if the first judgment unit judges that the motor is in a load state; a phase-loss protection unit, used to perform phase-loss protection on the motor if the second judgment unit judges that the motor is phase-loss.

[0011] Optionally, the first judgment unit judges whether the motor is in a load state or a no-load state according to the output current of the motor, including: judging whether the output current of the motor is greater than zero and less than or equal to a first preset output current threshold; if it is judged that the output current of the motor is greater than zero and less than or equal to the first preset output current threshold, it is determined that the motor is in a load state; if it is judged that the output current of the motor is equal to zero or greater than the first preset output current threshold, it is determined that the motor is in a no-load state.

[0012] Optionally, the first preset output current threshold is obtained by: detecting the average value of the three-phase output current at the highest speed of the motor in a no-load state and the average value of the three-phase output current at the lowest speed of the motor in a loaded state; determining the first preset output current threshold according to the average value of the three-phase output current at the highest speed of the no-load state and the average value of the three-phase output current at the lowest speed of the loaded state; wherein the first preset output current threshold is equal to the sum of the average value of the three-phase output current at the highest speed of the motor in a no-load state and the preset current value, and the first preset output current threshold is less than the average value of the three-phase output current at the lowest speed of the motor in a loaded state.

[0013] Optionally, the second judgment unit judges whether the motor is phase-deficient according to the output current of the motor, including: judging whether the output current of the motor is less than a second preset output current threshold and lasts for a first preset time; if it is judged that the output current of the motor is less than the second preset output current threshold and lasts for the first preset time, then controlling the motor to stop for the second preset time and then restart, and re-judging whether the motor is phase-deficient, and so on; when it is judged that the output current of the motor is less than the second preset output current threshold and lasts for the first preset time for N consecutive times, it is determined that the motor is phase-deficient.

[0014] Optionally, the second preset output current threshold is obtained by respectively detecting the output currents of the other two phases when one of the three phases of the motor is disconnected at the lowest speed in the load state, and taking the average value of the detected three-phase output current as the second preset output current threshold.

[0015] Another aspect of the present invention provides a storage medium having a computer program stored thereon, wherein the program implements the steps of any of the aforementioned methods when executed by a processor.

[0016] Another aspect of the present invention provides a motor controller, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the aforementioned methods when executing the program.

[0017] In another aspect, the present invention provides a motor controller, comprising any of the above-mentioned motor phase loss protection devices.

[0018] In yet another aspect, the present invention provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of any of the aforementioned methods are implemented.

[0019] According to the technical solution of the present invention, the motor is determined to be in a no-load state or a loaded state by judging the magnitude of the motor output current value. Phase loss protection is not performed in the no-load state, thereby avoiding false triggering of no-load phase loss. In the loaded state, whether the motor is phase-lost is determined based on the magnitude of the motor output current value, thereby performing phase loss protection when it is determined that the motor is phase-lost.

[0020] According to the technical solution of the present invention, the output current threshold for no-load judgment is determined based on the average value of the three-phase output current at the highest speed in the no-load state and the average value of the three-phase output current at the lowest speed in the load state, so as to judge whether the motor is in a no-load state and avoid the phenomenon of false triggering of the phase loss protection in the no-load state.

[0021] According to the technical solution of the present invention, the output current threshold of the motor phase loss is determined according to the output currents of the other two phases when each motor is missing one phase under the lowest speed in the load state, so that it is possible to accurately judge whether the motor is missing a phase, so as to perform phase loss protection and solve the abnormal problems of low reliability of phase loss, excessive output current caused by untimely protection, and motor damage.

[0022] According to the technical solution of the present invention, when the motor output current value is lower than the threshold and lasts for a period of time, it is judged that the motor is phase-lost once. The motor phase-lost is determined only after the preset number of phase-lost identifications have been performed, which makes the identification of the motor phase-lost more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 1 is a method schematic diagram of an embodiment of a motor phase loss protection method provided by the present invention;

[0025] Figure 2 It is a method schematic diagram of a specific embodiment of the motor phase loss protection method provided by the present invention;

[0026] Figure 3 It is a structural block diagram of an embodiment of a motor phase loss protection device provided by the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] The present invention provides a motor phase loss protection method. The method is mainly used for phase loss protection of a permanent magnet synchronous motor, and is particularly suitable for a phase loss protection algorithm of a permanent magnet synchronous motor in sensorless vector control.

[0030] Figure 1 It is a method schematic diagram of an embodiment of a motor phase loss protection method provided by the present invention.

[0031] like Figure 1 As shown, according to one embodiment of the present invention, the motor phase loss protection method at least includes step S110, step S120 and step S130.

[0032] Step S110, judging whether the motor is in a loaded state or an unloaded state according to the output current of the motor.

[0033] In a specific implementation, it is determined whether the output current of the motor is greater than zero and less than or equal to a first preset output current threshold; if it is determined that the output current of the motor is greater than zero and less than or equal to the first preset output current threshold, it is determined that the motor is in a loaded state; if it is determined that the output current of the motor is equal to zero or greater than the first preset output current threshold, it is determined that the motor is in a no-load state. The output current can specifically be the current of any one of the three phases of the motor.

[0034] The first preset output current threshold is obtained by: detecting the average value of the three-phase output current at the highest speed of the motor in the no-load state and the average value of the three-phase output current at the lowest speed of the motor in the load state; determining the first preset output current threshold according to the average value of the three-phase output current at the highest speed of the no-load state and the average value of the three-phase output current at the lowest speed of the load state. The first preset output current threshold is equal to the sum of the average value of the three-phase output current at the highest speed of the motor in the no-load state and the preset current value, and the first preset output current threshold is less than the average value of the three-phase output current at the lowest speed of the motor in the load state.

[0035] For example, Table 1 shows the three-phase output current at different speeds in the no-load state of the motor, and Table 2 shows the three-phase output current at different speeds in the load state of the motor. It can be obtained from Tables 1 and 2 that the output current at the highest speed N4 in the no-load state of the motor is less than the output current at the lowest speed N5 in the load state, that is, the values ​​of Iu4, Iv4, and Iw4 are all less than Iu5, Iv5, and Iw5. The average value of the three-phase output current at the highest speed in the no-load state is I4, and the average value of the three-phase output current at the lowest speed in the load state is I5, then the output current threshold for motor no-load identification is obtained, that is, the first output current threshold Im=I4+preset current value<I5, and the preset current value is the preset margin. Since the output current of the motor will have abnormal fluctuations during the sampling process or under high temperature conditions, adding a certain margin can prevent recognition errors.

[0036] Table 1

[0037]

[0038] Table 2

[0039]

[0040] The motor's no-load condition is determined based on the output current threshold value obtained when the motor is in no-load condition. The motor's current real-time output current is Is. When 0<Is≤Im, the motor is determined to be in a load condition and phase loss protection can be performed (the main control chip issues a command to shut down the PWM to stop the motor). Otherwise, the motor is determined to be in a no-load condition and no phase loss protection is performed.

[0041] Step S120: If it is determined that the motor is in a no-load state, it is not determined whether the motor is missing a phase.

[0042] Step S130: If it is determined that the motor is in a load state, whether the motor is missing a phase is determined according to the output current of the motor.

[0043] If the motor is judged to be in a load state, phase loss protection can be performed (the main control chip sends a command to shut down the PWM to stop the motor). Otherwise, the motor is judged to be in a no-load state and no phase loss protection is performed. No-load is generally used for long-term, reliability, protection and other experimental verifications in the motor development stage. If the motor stops due to the accidental triggering of phase loss protection during long-term experiments, it will increase the R&D cost and delay the progress of product development. According to the current output current of the motor, it is judged whether the motor is in a no-load state. No phase loss protection is performed in the no-load state to avoid the no-load phase loss error triggering.

[0044] In a specific embodiment, it is determined whether the output current of the motor is less than a second preset output current threshold and lasts for a first preset duration; if it is determined that the output current of the motor is less than the second preset output current threshold and lasts for the first preset duration, the motor is controlled to stop for a second preset duration and then restarted, and it is determined again whether the motor is phase - missing, and so on; when it is continuously determined N times that the output current of the motor is less than the second preset output current threshold and lasts for the first preset duration, it is determined that the motor is phase - missing.

[0045] The second preset output current threshold is obtained in the following way: the output currents of the other two phases when one phase of the three - phase of the motor is disconnected at the lowest rotational speed of the load state are respectively detected, and the average value of the detected three - phase output currents is taken as the output current threshold for motor phase - missing, that is, the second preset output current threshold.

[0046] For example, Table 3 shows the output currents of the other two phases when one phase is missing at the lowest rotational speed of the motor load state. As shown in Table 3, when any one of the three phases is disconnected, the average value of the three - phase output currents Iu5e, Iv5e, and Iw5e in the table is taken as Iq, which is used as the output current threshold for motor phase - missing, that is, the second preset output current threshold. The first preset duration Tq can be taken as 1 s, for example, and the second preset duration can be taken as 10 s, for example. N≥3, and is taken as N = 3 times, for example. When Is < Iq and lasts for a certain time Tq, it is determined that there is one phase - missing, and the motor stops for 10 s and then restarts until it is determined that there is a "real" phase - missing after repeating the phase - missing action 3 times.

[0047] Table 3

[0048]

[0049] In step S140, if it is determined that the motor is phase - missing, the motor is controlled to stop to perform phase - missing protection on the motor.

[0050] Specifically, the motor is controlled to stop. For example, the main control chip can issue an instruction to turn off the PWM to stop the motor. The main control chip issues an instruction to turn off the tubes of the power switch module to stop the motor to achieve the protection effect. If the motor is not found to be phase - missing, it continues to run stably.

[0051] According to the above embodiments of the present invention, the output current threshold for motor phase loss is determined based on the output currents of the other two phases when each phase of the motor is missing at the lowest rotational speed according to the load state, so that it is possible to accurately determine whether the motor is missing a phase for phase loss protection. It can avoid the phenomenon that under high-temperature working conditions, parameters such as the motor resistance and inductance change, causing the output current to fluctuate close to the phase loss threshold (in the phase loss protection in the related art, the motor phase loss threshold is set very small, and the output current under no-load is also very small. When the current has abnormal fluctuations, their values are very close, resulting in phase loss), and the phenomenon of motor phase loss protection shutdown. At the same time, this control method can also identify that the motor is in an unloaded state and does not perform phase loss protection under no-load conditions, which can avoid false triggering of no-load phase loss and save the time of the experimental process. During the process of judging phase loss, the method of combining the judgment time and the number of times is adopted, which prevents the problem of phase loss protection shutdown caused by sudden abnormal current, has strong reliability, and is applicable to motors controlled by the sensorless vector scheme.

[0052] To clearly illustrate the technical solution of the present invention, the execution process of the motor phase loss protection method provided by the present invention will be described below with a specific embodiment.

[0053] Figure 2 It is a schematic diagram of the method of a specific embodiment of the motor phase loss protection method provided by the present invention. As Figure 2 shown, the current value of the motor winding is detected, and the real-time current value is taken as Is. By the output currents of the three phases U, V, and W of the motor in each preset rotational speed section under no-load and load states of the motor, the output current threshold Im for no-load state recognition is obtained.

[0054] Based on the obtained output current threshold (i.e., the first preset output current threshold) Im for no-load state recognition of the motor, the no-load and load conditions of the motor are judged. The output current of the motor during real-time operation is Is. When 0 < Is ≤ Im, it is judged that the motor is in a loaded state and phase loss protection can be performed. Otherwise, it is judged that the motor is in an unloaded state and no phase loss protection is performed.

[0055] When it is judged that the motor is in a loaded state, according to the output currents of the other two phases when any one of the three phases is disconnected at the lowest rotational speed of the detected load state, the average value of the three-phase currents is taken as the output current threshold Iq (i.e., the second preset output current threshold) for motor phase loss. When Is < Iq and it lasts for a certain time Tq, for example, Tq is greater than 1 s to determine a phase loss once. After the motor stops for 10 s, it restarts again until it is determined that the motor is phase lost after repeating the phase loss action 3 times, and phase loss protection is performed. If no phase loss is found in the motor, it continues to run stably.

[0056] The present invention also provides a motor phase loss protection device. This device is mainly used for the phase loss protection of permanent magnet synchronous motors, especially applicable to the phase loss protection algorithm of permanent magnet synchronous motors in sensorless vector control.

[0057] Figure 3 1 is a structural block diagram of an embodiment of the motor phase loss protection device provided by the present invention. Figure 3 As shown, the motor phase loss protection device 100 includes: a first judgment unit 110 , a second judgment unit 120 and a phase loss protection unit 130 .

[0058] The first judging unit 110 is used to judge whether the motor is in a loaded state or an unloaded state according to the output current of the motor.

[0059] In a specific implementation, it is determined whether the output current of the motor is greater than zero and less than or equal to a first preset output current threshold; if it is determined that the output current of the motor is greater than zero and less than or equal to the first preset output current threshold, it is determined that the motor is in a loaded state; if it is determined that the output current of the motor is equal to zero or greater than the first preset output current threshold, it is determined that the motor is in a no-load state. The output current can specifically be the current of any one of the three phases of the motor.

[0060] The first preset output current threshold is obtained by: detecting the average value of the three-phase output current at the highest speed of the motor in the no-load state and the average value of the three-phase output current at the lowest speed of the motor in the load state; determining the first preset output current threshold according to the average value of the three-phase output current at the highest speed of the no-load state and the average value of the three-phase output current at the lowest speed of the load state. The first preset output current threshold is equal to the sum of the average value of the three-phase output current at the highest speed of the motor in the no-load state and the preset current value, and the first preset output current threshold is less than the average value of the three-phase output current at the lowest speed of the motor in the load state.

[0061] For example, Table 1 shows the three-phase output current at different speeds in the no-load state of the motor, and Table 2 shows the three-phase output current at different speeds in the load state of the motor. It can be obtained from Tables 1 and 2 that the output current at the highest speed N4 in the no-load state of the motor is less than the output current at the lowest speed N5 in the load state, that is, the values ​​of Iu4, Iv4, and Iw4 are all less than Iu5, Iv5, and Iw5. The average value of the three-phase output current at the highest speed in the no-load state is I4, and the average value of the three-phase output current at the lowest speed in the load state is I5, then the output current threshold for motor no-load identification is obtained, that is, the first output current threshold Im=I4+preset current value<I5, and the preset current value is the preset margin. Since the output current of the motor will have abnormal fluctuations during the sampling process or under high temperature conditions, adding a certain margin can prevent recognition errors.

[0062] Table 1

[0063]

[0064] Table 2

[0065]

[0066] The motor's no-load condition is determined based on the output current threshold value obtained when the motor is in no-load condition. The motor's current real-time output current is Is. When 0<Is≤Im, the motor is determined to be in a load condition and phase loss protection can be performed (the main control chip issues a command to shut down the PWM to stop the motor). Otherwise, the motor is determined to be in a no-load condition and no phase loss protection is performed.

[0067] No-load is generally used for long-term, reliability, protection and other experimental verifications in the motor development stage. If the motor stops due to mistaken triggering of phase loss protection during long-term experiments, it will increase R&D costs and delay product development progress. Judging whether the motor is in a no-load state based on the current output current of the motor can avoid mistaken triggering of no-load phase loss.

[0068] The second judgment unit 120 is used for not judging whether the motor is missing a phase if the first judgment unit judges that the motor is in a no-load state; if the first judgment unit judges that the motor is in a load state, judging whether the motor is missing a phase according to the output current of the motor.

[0069] Specifically, if the first judgment unit 110 judges that the motor is in a no-load state, the second judgment unit 120 does not judge whether the motor is out of phase; if the first judgment unit 110 judges that the motor is in a load state, the second judgment unit 120 judges whether the motor is out of phase according to the output current of the motor. In a specific implementation, it is judged whether the output current of the motor is less than the second preset output current threshold and lasts for a first preset time; if it is judged that the output current of the motor is less than the second preset output current threshold and lasts for the first preset time, the motor is controlled to be stopped for the second preset time and then restarted, and whether the motor is out of phase is re-judged, and so on; when it is judged that the output current of the motor is less than the second preset output current threshold and lasts for the first preset time for N consecutive times, it is determined that the motor is out of phase.

[0070] The second preset output current threshold is obtained in the following manner: respectively detecting the output currents of the other two phases when one of the three phases of the motor is disconnected at the lowest speed in the load state, and taking the average value of the detected three-phase output currents as the output current threshold of the motor's missing phase, that is, the second preset output current threshold.

[0071] For example, Table 3 shows the output currents of the other two phases when one phase is missing at the lowest rotational speed of the motor load state. As shown in Table 3, when any one of the three phases is disconnected, the average value of the three-phase output currents Iu5e, Iv5e, and Iw5e in the table is taken as Iq, which serves as the output current threshold for motor single-phase loss, that is, the second preset output current threshold. The first preset duration Tq can be taken as 1 s, for example, and the second preset duration can be taken as 10 s, for example. N ≥ 3, and is taken as N = 3 times, for example. When Is < Iq and lasts for a certain time Tq, it is determined that there is a single-phase loss once. The motor stops and restarts after 10 s until it is determined that there is a "real" single-phase loss after repeating the single-phase loss action 3 times.

[0072] Table 3

[0073]

[0074] The single-phase loss protection unit 130 is used to control the motor to stop when the second judgment unit determines that the motor has a single-phase loss, so as to perform single-phase loss protection on the motor.

[0075] Specifically, control the motor to stop. For example, the main control chip can issue an instruction to turn off the PWM to stop the motor. The main control chip issues an instruction to turn off the tubes of the power switch module to stop the motor to achieve the protection effect. If the motor does not detect a single-phase loss, it will continue to run stably.

[0076] According to the above embodiments of the present invention, the output current threshold for motor single-phase loss is determined based on the output currents of the other two phases when each phase of the motor is missing at the lowest rotational speed of the load state, so as to accurately judge whether the motor has a single-phase loss for single-phase loss protection. It can avoid the phenomenon that under high-temperature working conditions, parameters such as the motor resistance and inductance change, causing the output current to fluctuate close to the single-phase loss threshold (in the single-phase loss protection of the related art, the single-phase loss threshold of the motor is set very small, and the output current under no-load is also very small. When the current has abnormal fluctuations, their values are very close, resulting in single-phase loss), and the phenomenon of the motor stopping due to single-phase loss protection. At the same time, this control method can also identify that the motor is in an unloaded state and does not perform single-phase loss protection under no-load conditions, which can avoid mis-triggering of single-phase loss under no-load and save the time of the experimental process. In the process of judging single-phase loss, the method of combining long judgment time and number of times is adopted to prevent the problem of the motor stopping due to sudden abnormal current, with strong reliability, and is applicable to motors controlled by the sensorless vector control scheme.

[0077] The present invention also provides a storage medium corresponding to the motor single-phase loss protection method, on which a computer program is stored. When the program is executed by a processor, the steps of any of the foregoing methods are implemented.

[0078] The present invention also provides a motor controller corresponding to the motor phase loss protection method, including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the aforementioned methods when executing the program.

[0079] The present invention also provides a motor controller corresponding to the motor phase loss protection device, comprising any of the motor phase loss protection devices described above.

[0080] The present invention also provides a computer program product corresponding to the motor phase loss protection method, including a computer program, and when the computer program is executed by a processor, the steps of any of the aforementioned methods are implemented.

[0081] Accordingly, the solution provided by the present invention determines whether the motor is in a no-load state or a loaded state by judging the size of the motor output current value. In the no-load state, no phase loss protection is performed, thereby avoiding false triggering of no-load phase loss. In the loaded state, whether the motor is phase-lost is determined according to the size of the motor output current value, thereby performing phase loss protection when it is determined that the motor is phase-lost.

[0082] According to the technical solution of the present invention, the output current threshold for no-load judgment is determined based on the average value of the three-phase output current at the highest speed in the no-load state and the average value of the three-phase output current at the lowest speed in the load state, so as to judge whether the motor is in the no-load state and avoid false triggering of the phase loss protection in the no-load state.

[0083] According to the technical solution of the present invention, the output current threshold of the motor phase loss is determined according to the output currents of the other two phases when each motor loses one phase at the lowest speed in the load state, so that it is possible to accurately judge whether the motor is phase-lost for phase loss protection.

[0084] According to the technical solution of the present invention, when the motor output current value is lower than the threshold and lasts for a period of time, it is judged that the motor is phase-lost once. The motor phase-lost is determined only after the preset number of phase-lost identifications have been performed, which makes the identification of the motor phase-lost more accurate.

[0085] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium or transmitted via a computer-readable medium. Other examples and implementations are within the scope and spirit of the present invention and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of these. In addition, each functional unit may be integrated into a processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit.

[0086] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0087] The units described as separate components may or may not be physically separated, and the components of the control device may or may not be physical units, that is, they may be located in one place or distributed in multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0088] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the relevant technology or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0089] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A motor phase loss protection method, characterized in that: include: According to the output current of the motor, determining whether the motor is in a loaded state or an unloaded state; If it is determined that the motor is in a no-load state, it is not determined whether the motor is phase-lost; If it is determined that the motor is in a load state, determining whether the motor is phase-deficient according to the output current of the motor; If it is determined that the motor is missing a phase, the motor is controlled to stop to perform phase-loss protection on the motor.

2. The method according to claim 1, characterized in that Judging whether the motor is in a loaded state or an unloaded state according to the output current of the motor includes: Determining whether the output current of the motor is greater than zero and less than or equal to a first preset output current threshold; If it is determined that the output current of the motor is greater than zero and less than or equal to a first preset output current threshold, it is determined that the motor is in a load state; If it is determined that the output current of the motor is equal to zero or greater than a first preset output current threshold, it is determined that the motor is in a no-load state.

3. The method according to claim 2, characterized in that The first preset output current threshold is obtained in the following manner: Detecting an average value of the three-phase output current at the highest speed of the motor in a no-load state and an average value of the three-phase output current at the lowest speed of the motor in a loaded state; Determine the first preset output current threshold value according to the average value of the three-phase output current at the highest speed in the no-load state and the average value of the three-phase output current at the lowest speed in the load state; Among them, the first preset output current threshold is equal to the sum of the average value of the three-phase output current at the highest speed of the motor in the no-load state and the preset current value, and the first preset output current threshold is less than the average value of the three-phase output current at the lowest speed of the motor in the load state.

4. The method according to any one of claims 1 to 3, characterized in that: Judging whether the motor is phase-deficient according to the output current of the motor includes: Determining whether the output current of the motor is less than a second preset output current threshold and lasts for a first preset time period; If it is determined that the output current of the motor is less than the second preset output current threshold value and lasts for the first preset time, the motor is controlled to be stopped for the second preset time and then restarted, and whether the motor is missing a phase is re-determined, and so on; When it is determined that the output current of the motor is less than the second preset output current threshold value N times in succession and lasts for a first preset time period, it is determined that the motor is phase-missing.

5. The method according to claim 4, characterized in that The second preset output current threshold is obtained in the following manner: The output currents of the other two phases when one of the three phases of the motor is disconnected at the lowest speed in the load state are respectively detected, and the average value of the detected three-phase output currents is taken as the second preset output current threshold.

6. A motor phase loss protection device, characterized in that: include: A first judging unit, used for judging whether the motor is in a loaded state or an unloaded state according to the output current of the motor; a second judgment unit, configured to not judge whether the motor is phase-lost if the first judgment unit judges that the motor is in a no-load state, and to judge whether the motor is phase-lost according to an output current of the motor if the first judgment unit judges that the motor is in a loaded state; The phase-loss protection unit is used to control the motor to stop if the second judgment unit judges that the motor is phase-loss, so as to perform phase-loss protection on the motor.

7. The device according to claim 6, characterized in that The first judging unit, judging whether the motor is in a loaded state or an unloaded state according to the output current of the motor, comprises: Determining whether the output current of the motor is greater than zero and less than or equal to a first preset output current threshold; If it is determined that the output current of the motor is greater than zero and less than or equal to a first preset output current threshold, it is determined that the motor is in a load state; If it is determined that the output current of the motor is equal to zero or greater than a first preset output current threshold, it is determined that the motor is in a no-load state.

8. A storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the steps of any method described in claims 1-5 are implemented.

9. A motor controller, characterized in that: The invention comprises a processor, a memory and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the method described in any one of claims 1 to 5 are implemented, including the motor phase loss protection device described in any one of claims 6 to 7.

10. A computer program product, characterized in that The invention comprises a computer program, which implements the steps of any one of the methods of claims 1 to 5 when executed by a processor.

Images