A method and device for detecting phase loss in a permanent magnet synchronous motor

Abstract

The present invention discloses a method and device for detecting phase loss in a permanent magnet synchronous motor. The permanent magnet synchronous motor adopts a star connection, phase current sampling adopts a resistance method, and the motor adopts a sine wave control method. The method determines whether any phase current in the three-phase current is in a zero-crossing region based on the current value of the three-phase current at the previous moment; and determines whether there is a phase loss current based on the current current value of the three-phase current, the current difference of the three-phase current, and whether the phase current is in the zero-crossing region, wherein the current difference of the three-phase current is the difference between the current current value of the three-phase current and the current value at the previous moment. The detection method and device provided by the present invention solve the delay problem during phase loss detection, the algorithm is easy to implement, and no additional hardware cost is added, thereby improving the speed and reliability of motor control phase loss detection.

Description

Technical Field

[0001] The present invention relates to a method and device for detecting phase loss of a three-phase circuit, and in particular to a method and device for detecting phase loss of a permanent magnet synchronous motor. Background Art

[0002] Existing household appliances widely use permanent magnet synchronous motors. When one or more phases fail to function during motor operation, this fault is called phase loss. This fault can be caused by a variety of factors, including poor contact between the motor wiring and the driver board, or disconnected internal coils. Phase loss can prevent the motor's stator winding current from flowing according to the preset pattern, resulting in unbalanced torque, increased vibration and noise, and potentially causing the motor to burn out.

[0003] A star connection for motors involves connecting the ends of the three motor windings together to form a common point. In my country, star connection is commonly used for stator windings in motors under 3 kW. This reduces the winding's withstand voltage, thereby lowering the insulation rating and starting current. However, the drawback is that the motor's output power is reduced compared to a delta connection.

[0004] Among existing phase loss detection methods, one commonly used approach is to detect phase loss by comparing the difference between the maximum and minimum phase currents of each phase within each cycle with a current difference threshold. Another method is to determine phase loss by taking the difference between the maximum phase currents of each phase within each cycle and comparing it with a preset current threshold. However, the problem with these two methods is that once a phase loss occurs, the phase current value must be collected for at least one cycle to detect the defect. If the motor is running at a low speed at this time, for example, at an electrical frequency of 1Hz, a delay of at least 1s is required to detect the phase loss fault. Furthermore, if a phase of the motor has a defect at the zero crossing point, the phase current is zero at this time, making it impossible to quickly determine the phase loss. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defect of phase loss detection delay in the prior art and to provide a detection method and device that can quickly and accurately detect phase loss.

[0006] The present invention solves the above technical problems through the following technical solutions: a method for detecting phase loss in a permanent magnet synchronous motor, wherein the permanent magnet synchronous motor adopts a star connection, phase current sampling adopts a resistance method, and the motor adopts a sine wave control method, and is characterized in that:

[0007] Judging whether any phase current among the three-phase currents is in a zero-crossing region according to the current value of the three-phase current at the previous moment;

[0008] Whether there is a phase loss current is determined based on the current current value of the three-phase current, the current difference of the three-phase current, and whether there is a phase current in the zero-crossing region, wherein the current difference of the three-phase current is the difference between the current current value of the three-phase current and the current value at the previous moment.

[0009] Preferably, it is determined whether any phase current in the three-phase current is in the zero-crossing region according to the current value of the three-phase current at the previous moment; specifically, it is determined whether the absolute value of the current value of the three-phase current at the previous moment is greater than the preset current threshold value I min If yes, it means that no phase current is in the zero-crossing region; if no, it means that a phase current is in the zero-crossing region.

[0010] Preferably, judging whether there is a phase loss current based on the current value of the three-phase current, the current difference of the three-phase current, and whether any phase current is in the zero-crossing region includes:

[0011] If no phase current is in the zero-crossing region, it is determined whether any one of the three-phase currents satisfies the current value of zero and the absolute value of the corresponding current difference is greater than the first threshold current difference ΔI th1 If yes, then the phase current is missing; if no, then there is no missing phase current.

[0012] Preferably, judging whether there is a phase loss current based on the current value of the three-phase current, the current difference of the three-phase current, and whether any phase current is in the zero-crossing region includes:

[0013] If any phase current is in the zero-crossing region, it is gradually determined whether each phase in the three-phase current is missing.

[0014] Preferably, the step of determining whether each phase of the three-phase current is missing comprises:

[0015] Determine the phase current in the zero-crossing region among the three-phase currents, and judge whether the absolute values of the current differences of the other two phases are both less than the second threshold current difference ΔI th2 If so, the phase current in the zero-crossing region is missing.

[0016] If not, it is determined whether the other two phases meet the current value of zero and the absolute value of the corresponding current difference is greater than the first threshold current difference ΔI th1 If yes, then the phase current is missing, if not, then there is no missing phase current.

[0017] Preferably, the detection method further comprises: if there is a phase loss current, determining that the motor is phase-loss and stopping the motor; if there is no phase loss current, resampling the current current value of the three-phase current and re-judging.

[0018] Preferably, the detection method further comprises acquiring a current value of the three-phase current and a current value at a previous moment, and calculating a difference between the current value of the three-phase current and the current value at a previous moment to obtain a current difference.

[0019] Preferably, the preset current threshold I min 200mA≤I min ≤400mA.

[0020] Preferably, the first threshold current difference ΔI th1 100mA≤ΔI th1 ≤200mA.

[0021] Preferably, the second threshold current difference ΔI th2 5mA≤ΔI th2 ≤10mA.

[0022] Another aspect of the present invention provides a permanent magnet synchronous motor phase loss detection device, wherein the permanent magnet synchronous motor adopts a star connection, phase current sampling adopts a resistance method, and the motor adopts a sine wave control method, and is characterized by comprising:

[0023] The sampling unit is used to obtain the current value of the three-phase current in real time, including the current value and the current value at the previous moment;

[0024] an operation unit, for calculating the difference between a current value of the three-phase current and a current value at a previous moment;

[0025] A first judging unit is configured to judge whether any phase current among the three-phase currents falls into a zero-crossing region;

[0026] The second judging unit is configured to judge whether there is a missing phase current when no phase current falls into the zero-crossing region;

[0027] The third judgment unit is used to judge whether there is a phase loss current when a phase current falls into the zero-crossing area.

[0028] Preferably, the device further comprises a control unit, which controls the motor to stop if there is a phase loss current, and controls the motor to continue moving if there is no phase loss current, and the device continues to perform cyclic detection.

[0029] Preferably, the first judgment unit judges whether any phase current in the three-phase current falls into the zero-crossing region, specifically judging whether the absolute values of the current values of the three-phase current are all greater than the preset current threshold value I min If yes, it means that no phase current is in the zero-crossing region; if no, it means that a phase current is in the zero-crossing region.

[0030] Preferably, the second judgment unit includes

[0031] A first current judging unit is configured to judge whether any of the three currents has a current value of zero;

[0032] The first current difference judgment unit judges that the current value of any phase in the three-phase current is zero and the absolute value of the corresponding current difference is greater than the first threshold current difference ΔI th1 .

[0033] Preferably, the third judgment unit includes

[0034] a determination unit, configured to determine a phase in a zero-crossing region among the three-phase currents;

[0035] The second current difference judgment unit is used to judge whether the absolute values of the current differences of the other two phases are both less than the second threshold current difference ΔI th2 ;

[0036] A second current determination unit is configured to determine whether the absolute values of the current values of the other two phases are zero;

[0037] The third current difference judgment unit is used to judge whether the absolute value of the current difference between the other two phases is greater than the first threshold current difference ΔI th1 .

[0038] Another aspect of the present invention further provides an electronic device, comprising:

[0039] at least one processor; and

[0040] a memory communicatively connected to the at least one processor; wherein,

[0041] The memory stores instructions that can be executed by the at least one processor. The instructions are executed by the at least one processor to enable the at least one processor to perform the above method.

[0042] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause the computer to execute the above method.

[0043] The positive progressive effect of the present invention is that the permanent magnet synchronous motor phase loss detection method and detection device of the embodiment of the present invention solve the delay problem during phase loss detection, the algorithm is easy to implement, and does not increase the hardware cost, thereby improving the speed and reliability of motor control phase loss detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of current sampling of permanent magnet synchronous motor;

[0045] Figure 2 Schematic diagram of a three-phase star connection of a permanent magnet synchronous motor;

[0046] Figure 3 Schematic diagram of normal phase current of permanent magnet synchronous motor;

[0047] Figure 4 Schematic diagram of voltage injection in the zero-crossing region of a three-phase star-connected permanent magnet synchronous motor;

[0048] Figure 5 This is a schematic diagram of normal current in the non-zero-crossing region of a three-phase star-connected permanent magnet synchronous motor;

[0049] Figure 6 Schematic diagram of phase loss current in the non-zero-crossing region of a three-phase star-connected permanent magnet synchronous motor;

[0050] Figure 7 This is a schematic diagram of normal current in the zero-crossing region of a three-phase star-connected permanent magnet synchronous motor;

[0051] Figure 8 Schematic diagram of phase loss current in the zero-crossing region of a three-phase star-connected permanent magnet synchronous motor;

[0052] Figure 9 Schematic diagram of the flow of a method for detecting phase loss in a permanent magnet synchronous motor according to embodiment 1 of the present invention.

[0053] Figure 10 Schematic diagram of a permanent magnet synchronous motor phase loss detection device according to embodiment 2 of the present invention.

[0054] Figure 11 This is a schematic block diagram of an exemplary electronic device 500 provided in accordance with Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0055] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0056] like Figure 1-8 As shown in the figure, the permanent magnet synchronous motor is an AC three-phase motor, and adopts a three-phase star connection method. Phase current sampling adopts a resistance method. When the motor is operating normally, a sine wave control method is adopted, such as Figure 3 As shown in FIG, there are schematic diagrams of normal phase currents of phases a, b, and c.

[0057] Therefore, if the absolute values of the three-phase currents are all greater than the preset current threshold I min When , it means that no phase current is in the zero-crossing region, and the three-phase currents are all in the non-zero-crossing region. If the absolute value of any phase current is less than the preset current threshold, it means that there is a current in the three phases in the zero-crossing region.

[0058] like Figure 5 、 6As shown, it is a schematic diagram of the normal phase current and the phase current with a phase loss in the non-zero-crossing area. The three-phase currents are displayed with different icons respectively. Therefore, the phase current of the phase loss has a magnitude change that is greater than the first current threshold difference. Therefore, by judging the magnitude of the current difference between the current phase current and the phase current at the previous moment, it can also be judged whether there is a phase loss.

[0059] like Figure 7 、 8 As shown in the figure, it is a schematic diagram of normal phase current and phase missing current in the zero-crossing area. The three-phase currents are also displayed with different icons. If there is a zero-crossing phase current, it is necessary to use the magnitude of the absolute value of the phase current and the magnitude of the current difference to assist in judging whether there is a phase missing.

[0060] Example 1

[0061] like Figure 9 FIG. 1 is a flow chart of a method for detecting phase loss in a permanent magnet synchronous motor according to the present invention.

[0062] The specific steps are:

[0063] S1, motor operation, the motor operation adopts sine wave control mode;

[0064] S2, sampling the phase current, the phase current sampling adopts the resistance method; respectively obtain the current value of the three-phase current and the current value of the previous moment, for example, if they are phases a, b, and c, then the current values of the three phases are I a , I b , I c , the current values at the previous moment are I alast , I blast , I clast The previous moment and the current moment are related to the sampling frequency. The previous moment is the previous sampling point, and the current moment is the current sampling point. Therefore, the lag time of the phase loss detection is only the time interval between the previous and next samplings. The sampling frequency is consistent with the PWM frequency that generates the phase current. And the current difference of the three-phase current is calculated separately, that is,

[0065] ΔI a =I a -I alast

[0066] ΔI b =I b -I blast

[0067] ΔI c =I c -I clast

[0068] S3, judging whether any phase current in the three-phase current is in the zero-crossing region according to the current value of the three-phase current at the previous moment; specifically, judging whether the absolute value of the current value of the three-phase current at the previous moment is greater than the preset current threshold I min If yes, it means that no phase current is in the zero-crossing region; if no, it means that a phase current is in the zero-crossing region.

[0069] More specifically, the current values of the three phases at the previous moment are I alast , I blast , I clast , then judge {|I alast |,|I blast |,|I clast |} min >I min , that is, to determine whether the minimum value of the absolute value of the current value of the three-phase current at the previous moment is greater than the preset current threshold. If it is satisfied, it means that no phase current is in the zero-crossing region; if it is not satisfied, it means that a phase current is in the zero-crossing region. Preferably, the preset current threshold I min The size is 200mA≤I min ≤400mA, more preferably, I min =300mA.

[0070] S4: If no phase current is in the zero-crossing region, determine whether any of the three-phase currents satisfies the current value of zero and the absolute value of the corresponding current difference is greater than the first threshold current difference ΔI th1 If yes, then the phase current is missing; if no, then there is no missing phase current. The judgment process is to judge the three-phase currents abc in sequence.

[0071] This step is specifically to determine in steps whether there is a phase current whose current value is zero and the absolute value of the current difference is greater than the first threshold current difference ΔI th1 .

[0072] Preferably, it is to sequentially determine whether the current value of each phase is zero and the absolute value of the current difference is greater than the first threshold current difference ΔI th1 .

[0073] Specifically, including

[0074] S41, determine whether the a-phase current is zero and whether the absolute value of the current difference is greater than the first threshold current difference ΔI th1 , that is, to determine whether the following formula is true,

[0075] (I a = = 0) & & ( | ΔI a |>ΔI th1 ),

[0076] If the above equation is satisfied, then phase a is determined to be missing; if not, then phase a is not missing;

[0077] S42, determine whether the b-phase current is zero and whether the absolute value of the current difference is greater than the first threshold current difference ΔI th1 , that is, to determine whether the following formula is true,

[0078] (I b = = 0) & & ( | ΔI b |>ΔI th1 )

[0079] If the above equation is satisfied, then phase b is determined to be missing; if not, then phase b is not missing;

[0080] S43, determine whether the phase c current is zero and whether the absolute value of the current difference is greater than the first threshold current difference ΔI th1 , that is, to determine whether the following formula is true,

[0081] (I c = = 0) & & ( | ΔI c |>ΔI th1 )

[0082] If the above equation is satisfied, it is determined that phase C is missing. If not satisfied, phase C is not missing.

[0083] The above formula can be used to determine whether there is a current phase loss in the non-zero-crossing area. Preferably, the first threshold current difference ΔI th1 The size is 100mA≤ΔI th1 ≤200mA, more preferably, ΔI th1 =150mA.

[0084] S5: If any phase current is in the zero-crossing region, it is gradually determined whether each phase in the three-phase current is missing.

[0085] Specifically, it is determined step by step whether each phase of the three-phase current is missing, including:

[0086] S51 determines which phase of the three-phase current is in the zero-crossing region. Because this step requires that one phase be in the zero-crossing region, determining whether the absolute value of the phase current's value at the previous moment is less than or equal to a first preset current threshold is performed. After determining the phase current in the zero-crossing region, the phase current is set to x, and the other two phases are y and z. For example, if phase a is in the zero-crossing region, phase a is set to x, and phases b and c are y and z, respectively. That is, if x = a or b or c, then the other two phase currents {y, z} are non-zero-crossing phase currents, with {y, z} = {b, c} or {a, c} or {a, b}. Because the phase current in the zero-crossing region may be c or b, this setting is made to prevent confusion.

[0087] S52, determine whether the absolute values of the current differences of the other two phases are both less than the second threshold current difference ΔI th2 Specifically, determine the current difference ΔI between the other two phases, y and z y and ΔI z Whether the absolute values of are both less than the second threshold current difference, that is, whether the following formula is satisfied, whether the maximum value of the absolute values of the two is less than the second threshold current difference,

[0088] {|ΔI y |,|ΔI z |} max <ΔI th2

[0089] If yes, then the x-phase current in the zero-crossing region is out of phase; for example, in this embodiment, the a-phase current is out of phase. If no, proceed to the next step.

[0090] S53, respectively determine whether the other two phases meet the requirement that the current value is zero and the absolute value of the corresponding current difference is greater than the first threshold current difference ΔI th1 If yes, then the phase current is missing, if not, then there is no missing phase current.

[0091] This step is also a step-by-step judgment, that is, first judge whether the current value of the phase b current in the two phases is 0 and the current difference is greater than the first threshold current difference ΔI th1 , that is, whether the following formula is satisfied:

[0092] (I y = = 0) & & ( | ΔI y |>ΔI th1 )

[0093] If yes, the y-phase current is missing, if no, the y-phase is not missing.

[0094] Then determine whether the current value of the z-phase current in the two phases is 0 and the current difference is greater than the first threshold current difference ΔIth1 , that is, whether the following formula is satisfied:

[0095] (I z = = 0) & & ( | ΔI z |>ΔI th1 )

[0096] If yes, then the z phase current is missing, if no, then the z phase is not missing.

[0097] Preferably, the second threshold current difference ΔI th2 5mA≤ΔI th2 ≤10mA, more preferably, ΔI th2 =7.5mA.

[0098] S6, if there is a phase loss current, the motor is judged to be phase-lost and the motor is shut down; if there is no phase loss current, return to step S2, resample the current current value of the three-phase current, and re-judge.

[0099] The method of this embodiment analyzes and judges the characteristics of the phase current in the zero-crossing area and the non-zero-crossing area, and uses the phase current at the previous moment to determine whether it is in the zero-crossing area. It can accurately determine whether the motor is missing a phase at the current moment without causing any delay, and can reliably and quickly detect motor phase loss without adding additional hardware costs.

[0100] Example 2

[0101] like Figure 10 The figure shows a permanent magnet synchronous motor phase loss detection device, which specifically includes

[0102] The sampling unit 1 is used to obtain the current value of the three-phase current in real time. It includes three sub-units, each of which obtains the current value of the three-phase current. The sampling method of the sampling unit 1 adopts the resistance method, and the sampling frequency is consistent with the PWM frequency of the phase current. Therefore, the sampling unit specifically samples the current value and the current value at the previous moment. For example, if the current values of the three phases a, b, and c are respectively I a , I b , I c , the current values at the previous moment are I alast , I blast , I clast .

[0103] The calculation unit 2 is used to calculate the difference between the current value of the three-phase current and the current value at the previous moment.

[0104] ΔI a =I a -I alast

[0105] ΔI b =I b -I blast

[0106] ΔI c =I c -I clast

[0107] The first judgment unit 31 judges whether any phase current in the three-phase current falls into the zero-crossing region; specifically, it judges whether the absolute values of the current values of the three-phase current at the previous moment are all greater than the preset current threshold value I min If yes, it means that no phase current is in the zero-crossing region; if no, it means that a phase current is in the zero-crossing region.

[0108] Preferably, the current values of the three phases at the previous moment are I alast , I blast , I clast , then judge {|I alast |,|I blast |,|I clast |} min >I min , that is, to determine whether the minimum value of the absolute value of the current value of the three-phase current at the previous moment is greater than the preset current threshold. If it is satisfied, it means that no phase current is in the zero-crossing region; if it is not satisfied, it means that a phase current is in the zero-crossing region. Preferably, the preset current threshold I min The size is 200mA≤I min ≤400mA, more preferably, I min =300mA.

[0109] The second judgment unit 32 is used to judge whether there is a phase loss current when no phase current falls into the zero crossing area. Specifically, the second judgment unit 32 includes a first current judgment unit 341 and a first current difference judgment unit 351. The first current judgment unit 341 judges whether any of the three currents has a current value of zero, that is, judges I a = = 0, or I b = = 0, or I c = = 0; the first current difference judgment unit 351, determines whether the absolute value of the current difference in the three-phase current is greater than the first threshold current difference ΔI th1 |ΔI a |>ΔI th1 , or |ΔI b |>ΔI th1 , or |ΔI c |>ΔI th1 .

[0110] If a phase current satisfies both judgments at the same time, then the phase current is missing. If no phase current satisfies both judgments at the same time, then there is no current missing phase.

[0111] The device further includes a third judgment unit 33 for judging whether there is a phase loss current when a phase current falls into a zero-crossing region.

[0112] The third judgment unit 33 includes a determination unit 36, a second current difference judgment unit 352, a second current judgment unit 342 and a third current difference judgment unit 353. The determination unit 36 is used to determine a phase current in the zero-crossing region of the three-phase current. The determination method is to determine whether the absolute value of the current value of a phase of the three-phase current at the previous moment is less than the first preset current threshold, that is, I alast , I blast , I clast Is the absolute value of a phase in the current less than the first preset current threshold I min After the judgment, the current of the phase is set as phase x, and the other two phases are phases y and z. For example, if phase a is in the zero-crossing region after the judgment, then phase a is set as phase x, and the other two phases b and c are phases y and z, respectively.

[0113] The second current difference judgment unit 352 judges whether the absolute values of the current differences of the other two phases are both less than the second threshold current difference ΔI th2 That is, it is determined whether the absolute value of the current difference between the y-phase and the z-phase is less than the second threshold current difference ΔI th2 In this embodiment, it is determined whether

[0114] {|ΔI y |,|ΔI z |} max <ΔI th2 .

[0115] If it is satisfied, it can be judged that phase x is phase a, that is, the phase x in the zero-crossing region, that is, phase a is missing. If it is not satisfied, phase x is not missing, that is, phase a is not missing.

[0116] The second current judging unit 342 judges whether the absolute values of the current values of the other two phases are zero; specifically, it is to judge whether the absolute values of the current values of the other two phases are zero. y = = 0, or I z ==0.

[0117] The third current difference judgment unit 353 judges whether the absolute value of the current difference between the other two phases is greater than the first threshold current difference ΔI th1 , that is, to judge |ΔI y |>ΔI th1 , or |ΔI z |>ΔI th1 .

[0118] If one of the other two phases satisfies both conditions, then the phase is missing; if not, then the phase is not missing. Preferably, the determination is sequential, i.e., first determining whether phase y satisfies both conditions, and then determining whether phase z satisfies both conditions.

[0119] The device further comprises a control unit 4, which controls the motor to stop if there is a phase loss current, and controls the motor to continue to move if there is no phase loss current, and the device continues to cycle detection.

[0120] Example 3

[0121] Figure 11 A schematic block diagram of an example electronic device 500 that can be used to implement an embodiment of the present invention is shown. The device 500 includes a computing unit 501, which can perform various appropriate actions and processes according to a computer program stored in a ROM (Read-Only Memory) 502 or a computer program loaded from a storage unit 508 into a RAM (Random Access Memory) 503. Various programs and data required for the operation of the device 500 can also be stored in the RAM 503. The computing unit 501, the ROM 502, and the RAM 503 are connected to each other via a bus 504. An I / O (Input / Output) interface 505 is also connected to the bus 504.

[0122] Various components in device 500 are connected to I / O interface 505, including: an input unit 506, such as a keyboard, mouse, etc.; an output unit 507, such as various types of displays, speakers, etc.; a storage unit 508, such as a magnetic disk, optical disk, etc.; and a communication unit 509, such as a network card, modem, wireless communication transceiver, etc. The communication unit 509 allows device 500 to exchange information / data with other devices via a computer network such as the Internet and / or various telecommunication networks.

[0123] The computing unit 501 can be any general-purpose and / or specialized processing component with processing and computing capabilities. Some examples of the computing unit 501 include, but are not limited to, a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), various specialized AI (Artificial Intelligence) computing chips, various computing units that run machine learning model algorithms, a DSP (Digital Signal Processor), and any suitable processor, controller, microcontroller, etc. The computing unit 501 performs the various methods and processes described above, such as the phase loss detection method for a permanent magnet synchronous motor. For example, in some embodiments, the phase loss detection method for a permanent magnet synchronous motor can be implemented as a computer software program tangibly embodied in a machine-readable medium, such as the storage unit 508. In some embodiments, part or all of the computer program can be loaded and / or installed on the device 500 via the ROM 502 and / or the communication unit 509. When the computer program is loaded into the RAM 503 and executed by the computing unit 501, one or more steps of the method described above can be performed. Alternatively, in other embodiments, the computing unit 501 may be configured to execute the aforementioned method for detecting phase loss in a permanent magnet synchronous motor in any other appropriate manner (for example, by means of firmware).

[0124] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0125] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0126] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0127] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A method for detecting phase loss in a permanent magnet synchronous motor, wherein the permanent magnet synchronous motor adopts a star connection, phase current sampling adopts a resistance method, and the motor adopts a sine wave control method, characterized in that: Judging whether any phase current among the three-phase currents is in a zero-crossing region according to the current value of the three-phase current at the previous moment; Determining whether there is a phase loss current based on the current current value of the three-phase current, the current difference of the three-phase current, and whether the phase current is in a zero-crossing region, wherein the current difference of the three-phase current is the difference between the current current value of the three-phase current and the current value at the previous moment; Determine whether any phase current in the three-phase current is in the zero-crossing region based on the current value of the three-phase current at the previous moment; specifically, determine whether the absolute value of the current value of the three-phase current at the previous moment is greater than the preset current threshold If yes, it means that no phase current is in the zero-crossing region; if no, it means that a phase current is in the zero-crossing region; According to the current value of the three-phase current, the current difference of the three-phase current, and whether there is a phase current in the zero-crossing area, it is judged whether there is a phase current loss, including: If no phase current is in the zero crossing region, it is determined whether any one of the three phase currents satisfies the current value of zero and the absolute value of the corresponding current difference is greater than the first threshold current difference. If yes, then the phase current is missing; if no, then there is no missing phase current.

2. The method for detecting phase loss in a permanent magnet synchronous motor according to claim 1, wherein: According to the current value of the three-phase current, the current difference of the three-phase current, and whether there is a phase current in the zero-crossing area, it is judged whether there is a phase current loss. include, If any phase current is in the zero-crossing region, it is gradually determined whether each phase in the three-phase current is missing.

3. The method for detecting phase loss in a permanent magnet synchronous motor according to claim 2, wherein: Step by step, determine whether each phase of the three-phase current is missing, including: Determine the phase current in the zero-crossing region among the three-phase currents, and judge whether the absolute values of the current differences of the other two phases are both less than the second threshold current difference. If so, the phase current in the zero-crossing region is missing. If not, determine whether the other two phases meet the current value of zero and the absolute value of the corresponding current difference is greater than the first threshold current difference. If yes, then the phase current is missing, if not, then there is no missing phase current.

4. The method for detecting phase loss in a permanent magnet synchronous motor according to claim 1, wherein: The detection method further includes, if there is a phase loss current, determining that the motor is phase-lost and stopping the motor; If there is no phase loss current, the current values of the three-phase currents are resampled and the judgment is made again.

5. The method for detecting phase loss in a permanent magnet synchronous motor according to claim 1, wherein: The detection method further includes obtaining a current value of the three-phase current and a current value at a previous moment, and calculating a difference between the current value of the three-phase current and the current value at a previous moment to obtain a current difference.

6. The method for detecting phase loss in a permanent magnet synchronous motor according to claim 1, wherein: The preset current threshold 200mA≤ ≤400mA.

7. The method for detecting phase loss in a permanent magnet synchronous motor according to claim 1, wherein: The first threshold current difference 100mA≤ ≤200mA.

8. The method for detecting phase loss in a permanent magnet synchronous motor according to claim 3, wherein: The second threshold current difference 5mA≤ ≤10mA.

9. A permanent magnet synchronous motor phase loss detection device, wherein the permanent magnet synchronous motor adopts a star connection, phase current sampling adopts a resistance method, and the motor adopts a sine wave control method, characterized by: include, The sampling unit is used to obtain the current value of the three-phase current in real time, including the current value and the current value at the previous moment; an operation unit, for calculating the difference between a current value of the three-phase current and a current value at a previous moment; The first judgment unit is used to judge whether any phase current in the three-phase current falls into the zero-crossing region, specifically to judge whether the absolute value of the current value of the three-phase current is greater than the preset current threshold If yes, it means that no phase current is in the zero-crossing region; if no, it means that a phase current is in the zero-crossing region; The second judging unit is configured to judge whether there is a missing phase current when no phase current falls into the zero-crossing region; A third judgment unit is used to judge whether there is a phase loss current when a phase current falls into the zero-crossing region; The second judgment unit includes A first current judging unit is configured to judge whether any of the three-phase currents has a current value of zero; The first current difference judgment unit judges that the current value of any phase in the three-phase current is zero and the absolute value of the corresponding current difference is greater than the first threshold current difference. .

10. The permanent magnet synchronous motor phase loss detection device according to claim 9, characterized in that: It also includes a control unit, which controls the motor to stop if there is a phase loss current, and controls the motor to continue moving if there is no phase loss current. The device continues to cycle detection.

11. The permanent magnet synchronous motor phase loss detection device according to claim 9, characterized in that: The third judgment unit includes a determination unit, configured to determine a phase in a zero-crossing region among the three-phase currents; The second current difference judgment unit is used to judge whether the absolute values of the current differences of the other two phases are both less than the second threshold current difference. ; A second current determination unit is configured to determine whether the absolute values of the current values of the other two phases are zero; The third current difference judgment unit is used to judge whether the absolute value of the current difference between the other two phases is greater than the first threshold current difference. .

12. An electronic device comprising: at least one processor; as well as a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 8.

13. A non-transitory computer-readable storage medium storing computer instructions, wherein: The computer instructions are used to cause the computer to execute the method according to any one of claims 1-8.

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