Motor open-phase detection method and detection device
By real-time monitoring and analysis of the three-phase current, speed feedback and torque signals of the motor, combined with current imbalance and torque deviation, the reliability problem of phase loss detection when the motor speed changes greatly is solved, and the phase loss of the motor is achieved The accurate judgment improves the stability and safety of motor operation.
Patent Information
- Application Number
- CN202411327604.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2024-12-20
AI Technical Summary
The existing motor phase-lost detection methods are poor in detection when the motor speed changes greatly, and are prone to incorrect triggering or missed judgments, making it difficult to accurately judge the motor phase-lost condition.
By obtaining the three-phase current signal, speed feedback signal, torque reference signal and torque feedback signal, calculate the current imbalance and torque deviation, and correct it with the sliding average filter and speed feedback to determine whether the motor is in a phase-free state. , suitable for detection during high-speed and low-speed operation.
It improves the reliability of motor phase loss detection, accurately determines whether the motor is missing, avoids motor damage and production accidents caused by phase loss, and enhances the stability and safety of motor operation.
Smart Images
Figure CN119165350A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of robotics, and in particular to a motor phase loss detection method and a detection device. Background Art
[0002] SCARA robots are widely used in 3C, automobile, electronics, food, packaging, printing, automobile manufacturing and other industries. They can achieve high-precision and high-efficiency repeated positioning and have broad market prospects and application space. SCARA robots realize motor drive through an integrated controller unit and have the advantages of compact structure, high integration, small size, low cost and reliable operation. As an important component of robots, motor drive has developed rapidly in recent years, the technology has become increasingly mature, and the market share has continued to increase.
[0003] The drive motor is an important part of the robot system, mainly used to perform the robot's linear and rotational motion in space. The reliability and stability of its working state directly affects the operating safety and efficiency of the robot system. The operating state monitoring and fault diagnosis technology of the drive motor is an important part of the operating state monitoring and fault diagnosis technology of the robot system, and is a necessary prerequisite for realizing the operating state monitoring and fault diagnosis of the robot system. Monitoring and protecting the motor's operating state can detect motor faults in time, avoid motor damage, extend the motor's life, ensure the normal operation of the motor, improve the motor's operating reliability and efficiency, and improve the operating efficiency of the drive motor system. It is of great significance to improve the operating efficiency of the drive motor system.
[0004] At present, the motor operation status monitoring and fault diagnosis technology has been widely studied, mainly divided into two categories: fault detection and fault diagnosis. The motor fault detection technology is mainly divided into current detection and vibration detection. Current detection is based on the current characteristics of the motor. By detecting the input current, output current, current imbalance, current harmonics and other characteristic quantities of the motor, the motor operation status is judged, and the motor fault detection and diagnosis are realized. Vibration detection is based on the vibration characteristics of the motor. By detecting the vibration characteristic quantity of the motor, the motor operation status is judged, and the motor fault detection and diagnosis are realized.
[0005] Motor fault diagnosis technology is mainly divided into two categories: self-diagnosis and fault diagnosis. Self-diagnosis technology is mainly based on the self-diagnosis function of the motor. By integrating the fault diagnosis function module inside the motor, the internal fault of the motor is diagnosed, and the self-diagnosis function of the motor is realized. Fault diagnosis technology is mainly based on the fault characteristics of the motor. By detecting the fault characteristic quantity of the motor, the fault of the motor is diagnosed, and the fault diagnosis function of the motor is realized.
[0006] During the operation of the motor, a phase loss fault may occur due to poor contact, loose terminals, etc. The motor can run for a short period of time in the phase loss state, but the motor output becomes larger and the stability becomes lower, causing the robot performance to seriously deteriorate. Long-term operation may cause multiple fault alarms, resulting in the inability to find the correct direction when troubleshooting the alarm cause, increasing subsequent maintenance costs. Therefore, the robot controller needs to accurately detect the motor phase loss.
[0007] The existing motor phase loss algorithm can only determine the phase loss of a uniform speed motor. However, when the speed changes greatly, false triggering or missed detection is likely to occur, resulting in poor reliability of motor phase loss detection. Summary of the invention
[0008] The main purpose of the present invention is to provide a motor phase loss detection method and detection device, which can effectively detect the phase loss state when the motor speed changes greatly, and improve the reliability of motor phase loss detection.
[0009] In order to achieve the above object, according to one aspect of the present invention, a method for detecting a phase loss in a motor is provided, comprising:
[0010] Obtain three-phase current signal, speed feedback signal, torque given signal and torque feedback signal;
[0011] Determine the current unbalance degree according to the three-phase current signal;
[0012] Determine the corrected current imbalance according to the current imbalance and the speed feedback signal;
[0013] Determine the torque deviation square according to the torque given signal and the torque feedback signal;
[0014] Determine whether the motor is missing a phase based on the corrected current imbalance and the square of the torque deviation.
[0015] Furthermore, the step of determining the current imbalance degree according to the three-phase current signal includes:
[0016] Filter the three-phase current;
[0017] Compare and calculate the filtered three-phase current to obtain the maximum filtered current value Imax and the minimum filtered current value Imin;
[0018] The current imbalance Iimb is calculated based on the maximum filtered current value Imax and the minimum filtered current value Imin.
[0019] Furthermore, the step of filtering the three-phase current includes:
[0020] The u-phase current Iu, the v-phase current Iv, and the w-phase current Iw are squared and directly connected to the sliding average filter to obtain the filtered u-phase current Isu, the v-phase current Isv, and the w-phase current Isw. The calculation formula is as follows:
[0021]
[0022] Where n is the number of interruptions and N is the number of queues of the moving average filter.
[0023] Further, the step of determining the corrected current imbalance according to the current imbalance and the speed feedback signal includes:
[0024] Link the current imbalance Iimb with the motor running speed Vfdb;
[0025] The corrected current imbalance Ib is calculated by the following formula:
[0026]
[0027] Among them, K1 and K2 are fixed constants, K1>K2, V1 and V2 are fixed rates, V1>V2.
[0028] Further, Where V0 is the high and low speed dividing line for phase loss detection, b>a>1, N is the number of queues of the sliding average filter, T is the interruption time, and P is the number of motor pole pairs.
[0029] Further, Among them I b0 is the imbalance degree when running at a constant speed of 2V0, V0 is the high-speed and low-speed dividing line for phase loss detection, I b1 is the maximum current imbalance when operating in the range of V2 to V1; I b2 is the maximum current imbalance when operating in the range of 0 to V2, N is the number of queues of the sliding average filter, T is the interruption time, and P is the number of motor pole pairs.
[0030] Furthermore, K1=6, K2=1.5, V1=300r / min, V2=50r / min.
[0031] Further, the step of determining whether the motor is missing a phase according to the corrected current imbalance and the square of the torque deviation includes:
[0032] When the corrected current imbalance is greater than the set threshold, or the square of the torque deviation is greater than the set threshold and lasts for a preset time t1, it is determined that the motor is in a phase loss state.
[0033] Furthermore, the setting threshold of the corrected current imbalance Ib is 2 to 5 times the maximum phase loss protection imbalance when the motor is operating normally; the setting threshold of the torque deviation square is 5 to 10 times the maximum torque deviation square when the motor is operating normally.
[0034] According to another aspect of the present invention, there is provided a motor phase loss detection device, comprising:
[0035] The current acquisition module is used to collect the three-phase current signals of the motor in real time, including the u-phase current Iu, the v-phase current Iv, and the w-phase current Iw;
[0036] A filtering processing module is used to perform sliding average filtering on the collected three-phase current signals to obtain filtered three-phase currents Isu, Isv, and Isw;
[0037] The imbalance calculation module is used to calculate the current imbalance Iimb according to the filtered three-phase current;
[0038] Speed feedback module, used to obtain the real-time speed feedback Vfdb of the motor;
[0039] The torque reference module is used to obtain the set torque reference value Trq_ref;
[0040] Torque feedback module, used to obtain the real-time torque feedback Trq_fdb of the motor;
[0041] The phase loss judgment module is used to judge whether the motor is in a phase loss state based on the current imbalance Iimb, the speed feedback Vfdb, and the torque deviation Trq_eer. When the motor is running at a low speed, the phase loss judgment is performed by the current imbalance Ib and the set threshold. When the motor is running at a high speed, the phase loss judgment is performed by the square of the torque deviation and the set threshold.
[0042] The technical scheme of the present invention is applied, and the motor phase loss detection method includes: obtaining three-phase current signal, speed feedback signal, torque given signal and torque feedback signal; determining current imbalance according to the three-phase current signal; determining the corrected current imbalance according to the current imbalance and speed feedback signal; determining the torque deviation square according to the torque given signal and the torque feedback signal; judging whether the motor is phase-lost according to the corrected current imbalance and torque deviation square. The motor phase loss detection method combines two detection methods of current imbalance and torque deviation by real-time monitoring and analysis of the three-phase current, speed feedback, torque given value and torque feedback of the motor, and detects the phase loss state of the motor when running at high speed and low speed respectively, which can effectively detect the phase loss state when the motor speed changes greatly, accurately judge whether the motor is phase-lost, effectively avoid motor damage and production accidents caused by phase loss, and improve the stability and safety of motor operation. By real-time monitoring of the running state of the motor, the method can effectively prevent problems such as motor overheating, vibration aggravation and efficiency reduction caused by phase loss, and is suitable for equipment using three-phase motors in a wide range of fields such as industrial production, transportation, and construction facilities. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The drawings constituting a part of the present application are used to provide a further understanding 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:
[0044] Figure 1 A schematic structural diagram showing a cooling channel of an electric spindle structure according to an embodiment of the present invention; and
[0045] Figure 2 A schematic diagram of the rear end waterproof structure of the electric spindle structure of an embodiment of the present invention is shown. DETAILED DESCRIPTION
[0046] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0047] See also Figure 1 to Figure 2 As shown, according to an embodiment of the present invention, a motor phase loss detection method includes:
[0048] Obtain three-phase current signal, speed feedback signal, torque given signal and torque feedback signal;
[0049] Determine the current unbalance degree according to the three-phase current signal;
[0050] Determine the corrected current imbalance according to the current imbalance and the speed feedback signal;
[0051] Determine the torque deviation square according to the torque given signal and the torque feedback signal;
[0052] Determine whether the motor is missing a phase based on the corrected current imbalance and the square of the torque deviation.
[0053] The motor phase loss detection method combines the current imbalance and torque deviation detection methods by real-time monitoring and analysis of the motor's three-phase current, speed feedback, torque set value and torque feedback, and detects the motor phase loss state at high and low speeds respectively. It can effectively detect the phase loss state when the motor speed changes greatly, accurately determine whether the motor is phase-lost, effectively avoid motor damage and production accidents caused by phase loss, and improve the stability and safety of motor operation. By real-time monitoring of the motor's operating status, this method can effectively prevent problems such as motor overheating, increased vibration and reduced efficiency caused by phase loss, and is suitable for equipment using three-phase motors in a wide range of fields such as industrial production, transportation, and construction facilities.
[0054] The embodiment of the present invention obtains the u-phase current Iu, v-phase current Iv, w-phase current Iw, speed feedback Vfdb, torque reference Trq_ref, and torque feedback Trq_fdb through an acquisition module to calculate the current imbalance and torque deviation to detect the motor's phase loss operation condition in two ways.
[0055] Among the various detection methods for motor phase loss detection, current imbalance is suitable for high-speed detection, and torque deviation is suitable for low-speed detection. The number of sampled currents limits the detection of imbalance at low speed. Therefore, the torque deviation and current imbalance are combined to work together to detect the motor phase loss. This can accurately detect the phase loss when the motor is running at high speed, and can accurately detect the phase loss when the motor is running at low speed. This allows the motor phase loss detection method to adapt to different motor speeds, effectively detect the phase loss state when the motor speed changes greatly, and improve the reliability of motor phase loss detection. After using torque deviation to detect phase loss at low speed of the motor, the number of sampled currents is fixed when calculating the current imbalance, and no additional calculation is required. Only a single threshold needs to be confirmed, thereby lowering the threshold for using current imbalance.
[0056] After the motor phase loss is detected by combining the current imbalance and the torque deviation, the motor phase loss can be detected timely and accurately, and the alarm protection can be timely, thus improving the reliability of the motor phase loss detection.
[0057] In this embodiment, the original data of the three-phase current of the motor is acquired in real time through the current acquisition module of the motor controller. At the same time, the speed feedback and torque feedback signals of the motor are acquired. These data are the basis of the detection method.
[0058] In one embodiment, the step of determining the current imbalance according to the three-phase current signal includes:
[0059] Filter the three-phase current;
[0060] Compare and calculate the filtered three-phase current to obtain the maximum filtered current value Imax and the minimum filtered current value Imin;
[0061] The current imbalance Iimb is calculated based on the maximum filtered current value Imax and the minimum filtered current value Imin.
[0062] The maximum filter current value Imax and the minimum filter current value Imin are obtained by comparing and calculating the filtered u-phase current, v-phase current and w-phase current Isu Isv Isw. The current imbalance Iimb is calculated by the ratio of the maximum filter current value Imax to the minimum filter current value Imin.
[0063] The calculation formula of current imbalance Iimb is as follows:
[0064]
[0065] Isu, Isv, and Isw are the filter current values. The maximum filter current value Imax and the minimum filter current value Imin are obtained by comparing the three values. The formula is:
[0066] Imax=max(Isu,Isv,Isw);
[0067] Imin=min(Isu, Isv, Isw).
[0068] Current imbalance reflects the degree of imbalance of three-phase current and is a key indicator for detecting motor phase loss.
[0069] The acquired three-phase current data needs to be preprocessed to eliminate the influence of high-frequency noise. The preprocessing method includes squaring the original current data and then feeding it into a sliding average filter. The queue number N of the filter is a fixed parameter used to smooth the current data, reduce the influence of noise, and obtain the filtered three-phase currents Isu, Isv, and Isw.
[0070] Filtering can effectively remove noise from current signals and improve detection accuracy. It is particularly suitable for environments with severe electromagnetic interference, such as factory workshops and power systems.
[0071] In one embodiment, the step of filtering the three-phase current includes:
[0072] The u-phase current Iu, the v-phase current Iv, and the w-phase current Iw are squared and directly connected to the sliding average filter to obtain the filtered u-phase current Isu, the v-phase current Isv, and the w-phase current Isw. The calculation formula is as follows:
[0073]
[0074] Where n is the number of interruptions and N is the number of queues of the moving average filter.
[0075] In this embodiment, n, T and P are all determined according to the motor model and are related to the motor model. The number of queues N of the sliding average filter can be set by the user. The value of N cannot be too large, otherwise it will lead to excessive redundancy of data operations and low computing efficiency. The value of N cannot be too small, otherwise it will lead to too small data volume and poor accuracy of detection results. In one embodiment, N is 160.
[0076] In one embodiment, the step of determining the corrected current imbalance according to the current imbalance and the speed feedback signal comprises:
[0077] Link the current imbalance Iimb with the motor running speed Vfdb;
[0078] The corrected current imbalance Ib is calculated by the following formula:
[0079]
[0080] Among them, K1 and K2 are fixed constants, K1>K2, V1 and V2 are fixed rates, V1>V2.
[0081] When the motor runs at a low speed, the calculated current imbalance will increase as the speed feedback becomes lower. In order to prevent false triggering and missed triggering, the current imbalance of the phase loss protection needs to be linked to the motor's running speed. Different current imbalance thresholds are determined according to the motor's speed to improve the accuracy of the motor's phase loss detection at different speeds. By linking the current imbalance with the motor's running speed, the corrected current imbalance Ib can be obtained.
[0082] The embodiment of the present invention proposes a strategy for correcting the imbalance Iimb according to the speed feedback Vfdb to form the corrected current imbalance Ib. By setting the imbalance threshold value related to the motor speed, the sensitivity of the phase loss protection can be adjusted according to the different motor operating speeds, which is suitable for a wide range of motor operating ranges from low speed to high speed, and can effectively avoid the problems of false alarms and missed alarms at low speeds.
[0083] In one embodiment, Where V0 is the high and low speed dividing line for phase loss detection, b>a>1,
[0084] N is the number of queues of the sliding average filter, T is the interruption time, and P is the number of motor pole pairs.
[0085] This segmented setting can ensure that within different speed ranges, the phase loss protection is neither too sensitive to cause false alarms nor too slow to miss the protection opportunity, effectively improving the reliability of the protection.
[0086] Among them, V0 is the high and low speed dividing line of phase loss detection, which is related to the constant , 60 is the conversion factor of the speed unit r / min to r / s. In one embodiment,
[0087] In one embodiment, Among them I b0 is the imbalance degree when running at a constant speed of 2V0, V0 is the high-speed and low-speed dividing line for phase loss detection, I b1 is the maximum current imbalance when operating in the range of V2 to V1; I b2 is the maximum current imbalance when operating in the range of 0 to V2.
[0088] By properly setting the values of K1 and K2, the phase loss protection can maintain the best detection effect in all speed ranges of the motor operation. It is particularly suitable for motor applications that require frequent speed adjustment, such as elevators, cranes, etc.
[0089] In one embodiment, K1=6, K2=1.5, V1=300 r / min, V2=50 r / min.
[0090] The specific value setting needs to be adjusted according to the actual operating characteristics and working environment of the motor to ensure that the phase loss fault can be detected promptly and accurately at different speeds. It is suitable for industrial equipment that may occur at both high and low speeds.
[0091] In one embodiment, the step of determining whether the motor is missing a phase according to the corrected current imbalance and the square of the torque deviation includes:
[0092] When the corrected current imbalance is greater than a set threshold, or the square of the torque deviation is greater than a set threshold and lasts for a preset time t1, it is determined that the motor is in a phase loss state. In one embodiment, t1 is 10 ms.
[0093] The setting of the preset time takes into account the changes in the motor operating conditions. Specifically, when the motor is running at a low speed, the preset time t1 is longer, and when the motor is running at a high speed, the preset time t1 is shorter.
[0094] Combining the current imbalance and the square of the torque deviation for judgment can effectively avoid false alarms or missed alarms that may be caused by single indicator judgment, and improve the accuracy and reliability of phase loss detection.
[0095] In one embodiment, the threshold value of the corrected current imbalance Ib is 2 to 5 times the maximum phase loss protection imbalance when the motor is operating normally; the threshold value of the torque deviation square is 5 to 10 times the maximum torque deviation square when the motor is operating normally.
[0096] Reasonable setting of the threshold can ensure that no false alarm is triggered when the motor is operating normally, and that a timely response can be given when a phase failure occurs. It is suitable for motor equipment that requires continuous and stable operation, such as drive motors on production lines, wind turbines, etc.
[0097] In one embodiment, the determination of the phase loss state of the motor further includes monitoring the phase angle of the three-phase current signal. When the phase angle of any phase differs from the remaining two phases by more than a set angle, the phase loss state is further confirmed.
[0098] In one embodiment, in the motor phase loss detection method, when the motor is running at low speed, the phase loss is judged by the current imbalance Ib and the set threshold, and when the motor is running at high speed, the phase loss is judged by the square of the torque deviation and the set threshold. This speed-based phase loss detection strategy can effectively deal with the difference in phase loss characteristics of the motor at different operating speeds, ensure accurate phase loss protection at any speed, and is suitable for motors that need to operate stably in a wide speed range, such as drive motors of electric vehicles, high-speed rotating industrial pumps, etc.
[0099] According to an embodiment of the present invention, a motor phase loss detection device comprises:
[0100] The current acquisition module is used to collect the three-phase current signals of the motor in real time, including the u-phase current Iu, the v-phase current Iv, and the w-phase current Iw;
[0101] A filtering processing module is used to perform sliding average filtering on the collected three-phase current signals to obtain filtered three-phase currents Isu, Isv, and Isw;
[0102] The imbalance calculation module is used to calculate the current imbalance Iimb according to the filtered three-phase current;
[0103] Speed feedback module, used to obtain the real-time speed feedback Vfdb of the motor;
[0104] The torque reference module is used to obtain the set torque reference value Trq_ref;
[0105] Torque feedback module, used to obtain the real-time torque feedback Trq_fdb of the motor;
[0106] The phase loss judgment module is used to judge whether the motor is in a phase loss state based on the current imbalance Iimb, the speed feedback Vfdb, and the torque deviation Trq_eer. When the motor is running at a low speed, the phase loss judgment is performed by the current imbalance Ib and the set threshold. When the motor is running at a high speed, the phase loss judgment is performed by the square of the torque deviation and the set threshold.
[0107] The device can not only monitor the motor's operating status in real time, but also automatically adjust the phase loss detection strategy according to the motor's operating speed, effectively improving the safety and efficiency of the motor's operation. It is suitable for various motor applications that require high reliability and high-precision phase loss protection, such as precision machining equipment, automated production lines, new energy vehicles, etc.
[0108] The motor phase loss detection method and device of the embodiment of the present invention can accurately determine whether the motor is phase-lost by real-time monitoring and analysis of the three-phase current, speed feedback, torque set value and torque feedback of the motor, effectively avoiding motor damage and production accidents caused by phase loss, and improving the stability and safety of motor operation. The method and device are not only applicable to various types of motors, but also can provide accurate phase loss protection at different stages of motor operation, and have broad application prospects and significant economic benefits. For example, in the field of industrial automation, by implementing the phase loss detection method, the equipment downtime and maintenance costs caused by phase loss can be significantly reduced, and production efficiency and product quality can be improved. In the field of new energy vehicles, the device can ensure the stable operation of the drive motor under complex working conditions, improve the safety and driving experience of the vehicle. In building facilities, such as elevators and air-conditioning systems, the use of the phase loss detection method can effectively prevent motor failures, ensure the long-term reliable operation of equipment, and reduce maintenance workload. In addition, the method and device can also be applied to multiple fields such as power systems, transportation, and agricultural machinery, providing strong guarantees for the safe operation and efficiency improvement of motor equipment. In practical applications, the detection parameters should be optimized and adjusted according to the specific motor operating characteristics and working environment to achieve the best phase loss detection effect.
[0109] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.
[0110] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application 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 numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.
[0111] The above are only preferred embodiments of the present invention and are 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 replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for detecting a motor phase loss, characterized in that: include: Obtain three-phase current signal, speed feedback signal, torque given signal and torque feedback signal; Determine the current unbalance degree according to the three-phase current signal; Determine the corrected current imbalance according to the current imbalance and the speed feedback signal; Determine the torque deviation square according to the torque given signal and the torque feedback signal; Determine whether the motor is missing a phase based on the corrected current imbalance and the square of the torque deviation.
2. The motor phase loss detection method according to claim 1, characterized in that: The step of determining the current imbalance degree according to the three-phase current signal comprises: Filter the three-phase current; Compare and calculate the filtered three-phase current to obtain the maximum filtered current value Imax and the minimum filtered current value Imin; The current imbalance Iimb is calculated based on the maximum filtered current value Imax and the minimum filtered current value Imin.
3. The motor phase loss detection method according to claim 2, characterized in that: The step of filtering the three-phase current comprises: The u-phase current Iu, the v-phase current Iv, and the w-phase current Iw are squared and directly connected to the sliding average filter to obtain the filtered u-phase current Isu, the v-phase current Isv, and the w-phase current Isw. The calculation formula is as follows: Where n is the number of interruptions and N is the number of queues of the moving average filter.
4. The motor phase loss detection method according to claim 1, characterized in that: The steps of determining the corrected current imbalance according to the current imbalance and the speed feedback signal include: Link the current imbalance Iimb with the motor running speed Vfdb; The corrected current imbalance Ib is calculated by the following formula: Among them, K1 and K2 are fixed constants, K1>K2, V1 and V2 are fixed rates, V1>V2.
5. The motor phase loss detection method according to claim 4, characterized in that: Where V0 is the high and low speed dividing line for phase loss detection, b>a>1, N is the number of queues of the sliding average filter, T is the interruption time, and P is the number of motor pole pairs.
6. The motor phase loss detection method according to claim 4, characterized in that: Among them I b0 is the imbalance degree when running at a constant speed of 2V0, V0 is the high-speed and low-speed dividing line for phase loss detection, I b1 is the maximum current imbalance when operating in the range of V2 to V1; I b2 is the maximum current imbalance when operating in the range of 0 to V2, N is the number of queues of the sliding average filter, T is the interruption time, and P is the number of motor pole pairs.
7. The motor phase loss detection method according to claim 4, characterized in that: K1=6, K2=1.5, V1=300r / min, V2=50r / min.
8. The motor phase loss detection method according to claim 1, characterized in that: The steps of determining whether the motor is missing a phase according to the corrected current imbalance and the square of the torque deviation include: When the corrected current imbalance is greater than the set threshold, or the square of the torque deviation is greater than the set threshold and lasts for a preset time t1, it is determined that the motor is in a phase loss state.
9. The motor phase loss detection method according to claim 8, characterized in that: The setting threshold of the corrected current imbalance Ib is 2 to 5 times the maximum phase loss protection imbalance when the motor is operating normally; the setting threshold of the torque deviation square is 5 to 10 times the maximum torque deviation square when the motor is operating normally.
10. A motor phase loss detection device, characterized in that: include: The current acquisition module is used to collect the three-phase current signals of the motor in real time, including the u-phase current Iu, the v-phase current Iv, and the w-phase current Iw; A filtering processing module is used to perform sliding average filtering on the collected three-phase current signals to obtain filtered three-phase currents Isu, Isv, and Isw; The imbalance calculation module is used to calculate the current imbalance Iimb according to the filtered three-phase current; Speed feedback module, used to obtain the real-time speed feedback Vfdb of the motor; The torque reference module is used to obtain the set torque reference value Trq_ref; Torque feedback module, used to obtain the real-time torque feedback Trq_fdb of the motor; The phase loss judgment module is used to judge whether the motor is in a phase loss state based on the current imbalance Iimb, the speed feedback Vfdb, and the torque deviation Trq_eer. When the motor is running at a low speed, the phase loss judgment is performed by the current imbalance Ib and the set threshold. When the motor is running at a high speed, the phase loss judgment is performed by the square of the torque deviation and the set threshold.