Phase loss detection methods, systems, media, and electronic equipment for three-phase permanent magnet motors

Abstract

This invention provides a method, system, medium, and electronic device for detecting phase loss in a three-phase permanent magnet motor. The method includes: outputting a drive signal to control the motor to enter a pre-start working state; in the pre-start working state, the drive signal controls the lower bridge arm switch of the first phase of the motor to turn on and then turn off after a delay to charge the bootstrap capacitor of the motor drive circuit; after the bootstrap capacitor is charged, the drive signal controls the upper bridge arm switch of the first phase, the lower bridge arm switch of the second phase, and the lower bridge arm switch of the third phase of the motor to turn on for a preset time period and then turn off; during the preset time period, the current of the second phase and the current of the third phase of the motor are collected; if the current of the second phase or the current of the third phase is less than a preset threshold, the motor is determined to have a phase loss; otherwise, no phase loss is detected. This invention can detect phase loss faults in three-phase permanent magnet motors in a timely manner, avoid operation with faults, and improve operating efficiency.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology, and in particular relates to a method, system, medium and electronic equipment for detecting phase loss in a three-phase permanent magnet motor. Background Technology

[0002] Currently, indoor fans in air conditioning systems typically use three-phase permanent magnet motors as drive motors. If, before the motor starts, there is a loose or broken connection in the three-phase stator windings to the driver, the motor will exhibit noticeable vibration and abnormal noise. Existing phase loss detection methods require the motor to be running and the current value to be sampled to determine if a phase is missing. However, running the motor under abnormal conditions can cause damage to the motor itself and affect the accuracy of phase loss detection. Summary of the Invention

[0003] The purpose of this invention is to provide a method, system, medium, and electronic equipment for detecting phase loss in a three-phase permanent magnet motor, in order to solve the problem of how to detect phase loss faults in a three-phase permanent magnet motor in a timely manner and prevent the motor from operating in an abnormal state.

[0004] In a first aspect, the present invention provides a method for detecting a phase loss in a three-phase permanent magnet motor, the method comprising: outputting a drive signal to control the three-phase permanent magnet motor to enter a pre-start working state; in the pre-start working state, controlling the three-phase permanent magnet motor to start but not reach full speed rotation; in the pre-start working state, the drive signal controls the lower bridge arm switch of the first phase of the three-phase permanent magnet motor to be turned on and then turned off after a delay, to charge the bootstrap capacitor of the drive circuit of the three-phase permanent magnet motor; after the bootstrap capacitor is charged, the drive signal controls the upper bridge arm switch of the first phase and the lower bridge arm switch of the second phase of the three-phase permanent magnet motor to be turned on. The switch tubes of the first phase and the lower bridge arm of the third phase are turned on for a preset time period and then turned off. During the preset time period, the upper bridge arm switch tubes of the first phase, the lower bridge arm switch tubes of the second phase, and the lower bridge arm switch tubes of the third phase of the three-phase permanent magnet motor are all turned on to form a circuit loop, generating current that flows from the first phase of the three-phase permanent magnet motor to the second phase and the third phase of the three-phase permanent magnet motor, respectively. During the preset time period, the current of the second phase and the current of the third phase of the three-phase permanent magnet motor are collected. If the current of the second phase or the current of the third phase is less than a preset threshold, it is determined that the three-phase permanent magnet motor is missing a phase; otherwise, there is no phase loss.

[0005] In this invention, only one voltage pulse needs to be generated by controlling the three-phase permanent magnet motor drive circuit. The phase loss fault can be reliably detected without the three-phase permanent magnet motor rotating. The method is simple and reliable. Furthermore, based on cost considerations, the hardware circuit design of this invention adopts a dual-resistor current sampling design without speed and position sensors.

[0006] In one implementation of the first aspect, the length of the preset time period is: T = L * I / (VR * I); where L is the inductance parameter of the three-phase permanent magnet motor, I is the desired current value of the three-phase permanent magnet motor, V is the voltage value of the DC bus of the three-phase permanent magnet motor driver, and R is the resistance of the three-phase permanent magnet motor.

[0007] In one implementation of the first aspect, determining that the three-phase permanent magnet motor is missing a phase if the current of the second phase or the current of the third phase is less than a preset threshold includes: determining that the second phase of the three-phase permanent magnet motor is missing a phase if the current of the second phase is less than the preset threshold and the current of the third phase is not less than the preset threshold; determining that the third phase of the three-phase permanent magnet motor is missing a phase if the current of the third phase is less than the preset threshold and the current of the second phase is not less than the preset threshold; and determining that the first phase of the three-phase permanent magnet motor is missing a phase if both the current of the second phase and the current of the third phase are less than the preset threshold.

[0008] In one implementation of the first aspect, the current of the second phase of the three-phase permanent magnet motor is collected multiple times within the preset time period to obtain multiple second-phase current sampling values; if at least two of the multiple second-phase current sampling values ​​are greater than the preset threshold, it is determined that the second phase of the three-phase permanent magnet motor is not missing a phase; otherwise, it is determined that the second phase of the three-phase permanent magnet motor is missing a phase.

[0009] In one implementation of the first aspect, the current of the third phase of the three-phase permanent magnet motor is collected multiple times within the preset time period to obtain multiple third-phase current sampling values; if at least two of the multiple third-phase current sampling values ​​are greater than the preset threshold, it is determined that the third phase of the three-phase permanent magnet motor is not missing a phase; otherwise, it is determined that the third phase of the three-phase permanent magnet motor is missing a phase.

[0010] In this invention, the current sampling time is controlled at the microsecond level, making the entire detection process very fast. It does not require complex coordinate changes or PWM control. At the microsecond level, people will hardly feel any startup delay.

[0011] Secondly, the present invention provides a phase loss detection system for a three-phase permanent magnet motor, comprising: a control module connected to the three-phase permanent magnet motor and the upper arm, lower arm, upper arm, lower arm, upper arm, and lower arm of the first phase, respectively; for outputting control signals to control the operation of the three-phase permanent magnet motor; a first acquisition module connected to the second phase of the three-phase permanent magnet motor for acquiring the current of the second phase; a second acquisition module connected to the third phase of the three-phase permanent magnet motor for acquiring the current of the third phase; a first storage module connected to the first acquisition module for storing the current sampling values ​​acquired by the first acquisition module; a second storage module connected to the second acquisition module for storing the current sampling values ​​acquired by the second acquisition module; and a judgment module, built into the control module, for comparing the current sampling values ​​stored in the first storage module and the current sampling values ​​stored in the second storage module with preset thresholds respectively to determine whether the three-phase permanent magnet motor is missing a phase.

[0012] In one implementation of the second aspect, the control module includes: the control module is used to output a drive signal to control the three-phase permanent magnet motor to enter a pre-start working state; in the pre-start working state, the drive signal controls the lower bridge arm switch of the first phase of the three-phase permanent magnet motor to be turned on, so as to charge the bootstrap capacitor of the drive circuit of the three-phase permanent magnet motor; after the bootstrap capacitor is charged, the drive signal controls the upper bridge arm switch of the first phase, the lower bridge arm switch of the second phase, and the lower bridge arm switch of the third phase of the three-phase permanent magnet motor to be turned on for a preset time period and then turned off.

[0013] In one implementation of the second aspect, the first acquisition module is used to acquire the current flowing from the first phase to the second phase of the three-phase permanent magnet motor in the circuit and store it in the first storage module; the second acquisition module is used to acquire the current flowing from the first phase to the third phase of the three-phase permanent magnet motor in the circuit and store it in the second storage module. The judgment module is connected to the first storage module and the second storage module respectively, and is used to compare the current sampling value stored in the first storage module and the current sampling value stored in the second storage module with preset thresholds in sequence to determine whether the three-phase permanent magnet motor is missing a phase.

[0014] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that the computer program is executed by a processor to implement the phase loss detection method described in any of the preceding claims.

[0015] Fourthly, the present invention provides an electronic device, including at least one processor and a memory; the memory is used to store a computer program; the processor is connected to the memory and is used to execute the computer program stored in the memory, so that the phase loss detection device performs the phase loss detection method described above.

[0016] In summary, the phase loss detection method, system, medium, and electronic equipment for a three-phase permanent magnet motor described in this invention have the following beneficial effects:

[0017] (1) The phase loss detection method described in this invention is simple and reliable. It only requires a three-phase permanent magnet motor to generate a voltage pulse, and it can reliably detect phase loss faults without the three-phase permanent magnet motor rotating.

[0018] (2) The hardware circuit design of the present invention adopts a dual-resistance current sampling and no speed position sensor design, which saves costs.

[0019] (3) The present invention has strong anti-interference ability. When a voltage pulse is generated, the current value that can be detected is relatively large, which is much larger than the sampling error and static interference. The whole detection process is very fast and does not require complex coordinate changes and PWM control. The voltage pulse duration is controlled at the microsecond level, and people will not feel any start-up delay. Attached Figure Description

[0020] Figure 1 The diagram shown is a structural diagram of a three-phase permanent magnet motor drive circuit according to an embodiment of the present invention.

[0021] Figure 2 The flowchart shown is a process for detecting phase loss according to an embodiment of the present invention.

[0022] Figure 3 The diagram shown is a schematic diagram of the bootstrap capacitor charging according to an embodiment of the present invention.

[0023] Figure 4 The diagram shown is a schematic of the drive circuit according to an embodiment of the present invention.

[0024] Figure 5 The diagram shows the drive current flow direction as described in an embodiment of the present invention.

[0025] Figure 6 The diagram shown is a software implementation logic diagram according to an embodiment of the present invention.

[0026] Figure 7 The diagram shown is a schematic diagram of the phase loss detection system for a three-phase permanent magnet motor according to an embodiment of the present invention.

[0027] Figure 8 The diagram shown is a schematic representation of the electronic device structure according to an embodiment of the present invention.

[0028] Component designation explanation

[0029] 51 Control Module

[0030] 52 First Acquisition Module

[0031] 53 Second Acquisition Module

[0032] 54 First Storage Module

[0033] 55 Second storage module

[0034] 61 processor

[0035] 62 Memory

[0036] Steps S1 to S5 Detailed Implementation

[0037] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0038] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0039] The following embodiments of the present invention provide a method, system, medium and electronic equipment for detecting phase loss in a three-phase permanent magnet motor, which solves the technical problem of how to detect phase loss faults in a three-phase permanent magnet motor in a timely manner and prevent the motor from operating in an abnormal state.

[0040] The following will describe in detail, with reference to the accompanying drawings, the principle and implementation of a phase loss detection method, system, medium and electronic equipment for a three-phase permanent magnet motor according to this embodiment, so that those skilled in the art can understand the phase loss detection method, system, medium and electronic equipment for a three-phase permanent magnet motor according to this embodiment without creative effort.

[0041] The technical solutions of the present invention will now be described in detail with reference to the accompanying drawings.

[0042] like Figure 1As shown in the figure, the present invention provides a drive circuit structure diagram of a three-phase permanent magnet motor, including a three-phase permanent magnet motor M and a controller MCU. The controller MCU is used to send drive signals to control the operation of the three-phase permanent magnet motor.

[0043] Specifically, MCU stands for Microcontroller Unit, which refers to a microcontroller unit, also known as a single-chip microcomputer or microcontroller. It is a chip-level computer that appropriately reduces the frequency and specifications of the central processing unit (CPU) and integrates peripheral interfaces such as memory, timer, USB, A / D conversion, UART, PLC, DMA, and even LCD driver circuits onto a single chip, forming a chip-level computer that can perform different combinations of control for different applications.

[0044] Specifically, the controller MCU mainly includes a CPU (including an arithmetic logic unit, a control unit, and a register set), memory (including ROM and RAM), input and output I / O interfaces, timers, an interrupt system, special registers, etc.

[0045] The CPU in an MCU mainly consists of an arithmetic logic unit (ALU), a control unit, and a register set. It is the core component of the MCU, composed of two main parts: the ALU and the control unit. The ALU performs arithmetic and logical operations, bit variable processing, and data transfer. The control unit coordinates operations according to a specific timing sequence and is responsible for analyzing and executing instructions.

[0046] The memory (RAM and ROM) in an MCU includes ROM and RAM. ROM is the program memory; the MCU operates by executing pre-programmed instructions sequentially, and ROM stores this program (the system program is written and executed by the manufacturer). Storing data in ROM does not erase data after power loss. ROM is further divided into on-chip memory and off-chip (extended) memory. RAM is the data memory; data can be written to and retrieved at any time during program execution. Storing data in RAM does not retain data after power loss. RAM is also divided into on-chip data memory and off-chip (extended) memory.

[0047] The I / O interfaces in an MCU connect to external input and output (circuit) devices. Digital I / O interfaces such as P0 / P1 / P2 / P3 contain internal circuits including port latches, output drivers, and input buffers.

[0048] like Figure 2 As shown, in one embodiment of the present invention, the present invention provides a method for detecting phase loss in a three-phase permanent magnet motor, the detection method comprising the following steps:

[0049] Step S1: Output a drive signal to control the three-phase permanent magnet motor to enter the pre-start working state; in the pre-start working state, control the three-phase permanent magnet motor to start but not reach full speed rotation.

[0050] Specifically, the pre-start working state refers to the three-phase permanent magnet motor starting up but not yet reaching full speed rotation. Full speed rotation refers to the rotational speed of the motor during normal operation.

[0051] More specifically, in order to prevent the three-phase permanent magnet motor from rotating at large angles, the time for controlling the three-phase permanent magnet motor to be in the pre-start working state is generally selected to be relatively short, controlled in the microsecond range. The specific time selection depends on the parameters of the three-phase permanent magnet motor.

[0052] Step S2: In the pre-start working state, the drive signal controls the lower bridge arm switch of the first phase of the three-phase permanent magnet motor to turn on and then turn off after a delay, so as to charge the bootstrap capacitor of the three-phase permanent magnet motor drive circuit.

[0053] Specifically, such as Figure 3 The diagram shows a schematic of the bootstrap capacitor charging process according to an embodiment of the present invention. Taking phase W as an example, i.e., the first phase is phase W, the diagram illustrates the bootstrap capacitor charging process. L1 is the charging circuit for the bootstrap capacitor. When the drive signal controls the upper arm Q1 switch of the three-phase permanent magnet motor phase W to turn off and the lower arm Q2 switch of phase W to turn on, a 15V voltage source charges the bootstrap capacitor C1 through diode D1. After charging, there will be a 15V voltage across C1. In the next cycle, when the upper arm switch of phase W turns on and the lower arm switch of phase W turns off, the voltage at point A will approach 310V. Since the voltage across the capacitor cannot change abruptly, point B at the top of capacitor C1 will be raised to approximately 325V (ignoring the voltage drop in the circuit and the components themselves), thus ensuring the stable turn-on of the upper arm Q1 switch of phase W. Without the bootstrap capacitor C1, the gate voltage of the upper bridge arm Q1 of phase W would be almost equal to the emitter voltage the instant it is turned on, and thus the upper bridge arm Q1 of phase W would not be able to be turned on.

[0054] Step S3: After the bootstrap capacitor is fully charged, the drive signal controls the upper bridge arm switch of the first phase, the lower bridge arm switch of the second phase, and the lower bridge arm switch of the third phase of the three-phase permanent magnet motor to be turned on for a preset time period and then turned off.

[0055] Specifically, the length of the preset time period is: T = L * I / (VR * I); where L is the inductance parameter of the three-phase permanent magnet motor, I is the desired current value of the three-phase permanent magnet motor, V is the voltage value of the DC bus of the three-phase permanent magnet motor driver, and R is the resistance of the three-phase permanent magnet motor.

[0056] Specifically, during the preset time period, the upper bridge arm switch of the first phase, the lower bridge arm switch of the second phase, and the lower bridge arm switch of the third phase of the three-phase permanent magnet motor are all turned on to form a circuit loop, generating current that flows from the first phase of the three-phase permanent magnet motor to the second phase and the third phase of the three-phase permanent magnet motor, respectively.

[0057] Specifically, such as Figures 4-5 As shown, Figure 4 This diagram shows a driving circuit according to an embodiment of the present invention. Figure 5 The diagram shows the drive current flow as described in this embodiment of the invention. The lower bridge arm of the first phase of the three-phase permanent magnet motor is controlled to turn on and then turn off after a delay to charge the bootstrap capacitor. After the bootstrap capacitor is fully charged, the drive signal controls the upper bridge arm switch of the first phase, the lower bridge arm switch of the second phase, and the lower bridge arm switch of the third phase of the three-phase permanent magnet motor to all turn on for a preset time period and then turn off, forming a loop. Current is generated flowing from the first phase of the three-phase permanent magnet motor to the second and third phases of the three-phase permanent magnet motor, respectively. (Example...) Figure 5 As shown, the current flows from the upper bridge arm of the first phase (W phase) into the interior of the three-phase permanent magnet motor, and then flows out of the three-phase permanent magnet motor from the lower bridge arm of the second phase (U phase) along the L2 direction and the lower bridge arm of the third phase (V phase) along the L3 direction, respectively.

[0058] More specifically, the registers inside the MCU controller are manipulated to output high and low levels on the corresponding I / O ports. These high and low level signals are processed by the subsequent drive circuit and then control the upper and lower bridge arms of the inverter module's switching transistors. The upper bridge arm is generally connected to the positive terminal of the DC bus, and the lower bridge arm is connected to the negative terminal of the DC bus. Therefore, by controlling the lower bridge arm switch of the first phase of the three-phase permanent magnet motor to turn on and then turn off after a delay, the bootstrap capacitor of the three-phase permanent magnet motor drive circuit is charged. Then, by controlling the upper bridge arm of the first phase (e.g., the W phase) of the three-phase permanent magnet motor to turn on and then turn off within a preset time period, a voltage pulse is generated on the three-phase permanent magnet motor side. The peak value of this voltage pulse is the DC bus voltage value, and the duration of the voltage pulse is the aforementioned preset time period. At the same time, by controlling the lower bridge arms of the second and third phases (e.g., the U / V phases) of the three-phase permanent magnet motor to turn on, a loop is formed, and current flows from the first phase of the three-phase permanent magnet motor to the second and third phases, respectively.

[0059] More specifically, there are multiple implementation methods for the first, second, and third phases of the three-phase permanent magnet motor, and no specific limitation is made. In this embodiment of the invention, the first phase of the three-phase permanent magnet motor is the W phase, the second phase is the U phase, and the third phase is the V phase. That is, in the pre-start working state, a drive signal is output to control the lower bridge arm switch of the W phase of the three-phase permanent magnet motor to be turned on and then turned off after a delay, charging the bootstrap capacitor of the drive circuit of the three-phase permanent magnet motor. Then, the upper bridge arm of the W phase of the three-phase permanent magnet motor is turned on and then turned off within a preset time period. A voltage pulse is generated on the side of the three-phase permanent magnet motor. The duration of the voltage pulse is the preset time period mentioned above. At the same time, the lower bridge arms of the U phase and V phase of the three-phase permanent magnet motor are turned on, forming a circuit. Current flows from the W phase of the three-phase permanent magnet motor to the U phase and V phase of the three-phase permanent magnet motor, respectively.

[0060] Step S4: Collect the current of the second phase and the current of the third phase of the three-phase permanent magnet motor within the preset time period;

[0061] Specifically, during the preset time period, the upper bridge arm switch of the first phase, the lower bridge arm switch of the second phase, and the lower bridge arm switch of the third phase of the three-phase permanent magnet motor are all turned on to form a circuit loop, generating current that flows from the first phase of the three-phase permanent magnet motor to the second phase and the third phase of the three-phase permanent magnet motor, respectively. At the same time, the current of the second phase and the current of the third phase of the three-phase permanent magnet motor are collected during the preset time period.

[0062] More specifically, within the preset time period, after controlling the upper bridge arm of the first phase of the three-phase permanent magnet motor to turn on and then turn off within the preset time period, a voltage pulse is generated on the three-phase permanent magnet motor side. The duration of the voltage pulse is the aforementioned preset time period. Simultaneously, controlling the lower bridge arms of the second and third phases of the three-phase permanent magnet motor to turn on forms a loop, generating current that flows from the first phase of the three-phase permanent magnet motor to the second and third phases, respectively. Under the action of the voltage pulse, the detected current peak value only needs to be about two-thirds of the full-load current peak value. In this way, the current will flow from the first phase of the three-phase permanent magnet motor to the second and third phases. The current of the second and third phases is acquired at the same time as the switching transistor turns on. The current of the second and third phases is updated in a faster interruption, which is at least less than one-tenth of the aforementioned voltage pulse duration.

[0063] It should be noted that the detected peak current under voltage pulse is a variable that can be adjusted according to the actual situation of the three-phase permanent magnet motor. In this embodiment, the detected peak current is about two-thirds of the peak current at full load. In other embodiments, the detected peak current is 3 / 4 or 3 / 5 of the peak current at full load, etc., as long as there is current flowing from the first phase of the three-phase permanent magnet motor to the second and third phases, and the current of the second and third phases can be collected multiple times at the same time.

[0064] Step S5: If the current of the second phase or the current of the third phase is less than a preset threshold, it is determined that the three-phase permanent magnet motor is missing a phase; otherwise, it is not missing a phase.

[0065] Specifically, if the current of the second phase or the current of the third phase is less than a preset threshold, the three-phase permanent magnet motor is determined to be missing a phase, including: if the current of the second phase is less than the preset threshold and the current of the third phase is not less than the preset threshold, the second phase of the three-phase permanent magnet motor is determined to be missing a phase; if the current of the third phase is less than the preset threshold and the current of the second phase is not less than the preset threshold, the third phase of the three-phase permanent magnet motor is determined to be missing a phase; if both the current of the second phase and the current of the third phase are less than the preset threshold, the first phase of the three-phase permanent magnet motor is determined to be missing a phase.

[0066] To be more specific, in order to avoid interference and sampling errors, the current of the second and third phases of the three-phase permanent magnet motor can be sampled multiple times, and the recorded sampled data can be compared with the set threshold one by one. Only when at least two of the sampled data are greater than the threshold will it be determined as a missing phase.

[0067] Specifically, the current of the second phase of the three-phase permanent magnet motor is collected multiple times within the preset time period to obtain multiple second-phase current sampling values; if at least two of the multiple second-phase current sampling values ​​are greater than the preset threshold, it is determined that the second phase of the three-phase permanent magnet motor is not missing a phase; otherwise, it is determined that the second phase of the three-phase permanent magnet motor is missing a phase.

[0068] Specifically, the current of the third phase of the three-phase permanent magnet motor is collected multiple times within the preset time period to obtain multiple third-phase current sampling values; if at least two of the multiple third-phase current sampling values ​​are greater than the preset threshold, it is determined that the third phase of the three-phase permanent magnet motor is not missing a phase; otherwise, it is determined that the third phase of the three-phase permanent magnet motor is missing a phase.

[0069] In this embodiment of the invention, it is only necessary to control the three-phase permanent magnet motor to generate a voltage pulse, without the need for the three-phase permanent magnet motor to rotate, to reliably detect the phase loss fault. The method is simple and reliable. Furthermore, based on cost considerations, the hardware circuit design of this invention adopts a dual-resistor current sampling design without speed and position sensors.

[0070] like Figure 6 The diagram shown is a software implementation logic diagram of an embodiment of the present invention, which further helps those skilled in the art to understand a phase loss detection method for a three-phase permanent magnet motor without creative effort.

[0071] Specifically, such as Figure 6 As shown, before starting the three-phase permanent magnet motor, it is first determined whether the three-phase permanent magnet motor is in a stopped state and without faults. If the three-phase permanent magnet motor is in a stopped state and without faults, then defect detection is performed on the three-phase permanent magnet motor; otherwise, the operation is interrupted.

[0072] Determine whether the three-phase permanent magnet motor is in a stopped state and without faults, obtain the speed command of the three-phase permanent magnet motor, and evaluate the speed command. If the speed command is greater than 0, determine whether the three-phase permanent magnet motor is in a stopped state and without faults; otherwise, clear the current value detected before the last start of the three-phase permanent magnet motor.

[0073] If the three-phase permanent magnet motor is in a stopped and fault-free state, a phase loss detection is performed. First, LosePhaseDetectFinish_Flag = 0, stop_flag = 0, and current_ADcapture_flag = 1. That is, LosePhaseDetectFinish_Flag = 0 means that the phase loss detection completion flag of the three-phase permanent magnet motor is cleared to prevent the three-phase permanent magnet motor from entering the normal start-up process. Stop_flag = 0 means that the three-phase permanent magnet motor is in a non-stop state to prevent repeated phase loss judgment. Current_ADcapture_flag = 1 means that the flag for acquiring the sampling current has started.

[0074] Where stop_flag is the flag for the motor to stop; ErroType is the fault code, which equals 0 to indicate no fault; LosePhaseDetectFinish_Flag is the flag for the completion of static phase loss detection, which equals 1 to enter the normal startup logic; current_ADcapture_flag is the flag for starting to update current AD sampling, which equals 1 to start updating current AD sampling.

[0075] The three-phase permanent magnet motor is controlled to enter a pre-start working state. In the pre-start working state, the three-phase permanent magnet motor is started but not rotated. In the pre-start working state, the drive signal controls the lower bridge arm switch of the first phase of the three-phase permanent magnet motor to turn on and then turn off after a delay, charging the bootstrap capacitor of the three-phase permanent magnet motor drive circuit. After the bootstrap capacitor is charged, the drive signal controls the upper bridge arm switch of the first phase, the lower bridge arm switch of the second phase, and the lower bridge arm switch of the third phase of the three-phase permanent magnet motor to all turn on for a preset time period and then turn off. During the preset time period, the upper bridge arm switch of the first phase, the lower bridge arm switch of the second phase, and the lower bridge arm switch of the third phase of the three-phase permanent magnet motor are all turned on to form a circuit loop, generating current flowing from the first phase of the three-phase permanent magnet motor to the second and third phases of the three-phase permanent magnet motor, respectively.

[0076] Within the preset time period, the current of the second phase and the current of the third phase of the three-phase permanent magnet motor are collected. Simultaneously, the current sampling values ​​of the second phase and the third phase are obtained and recorded 10 times continuously to obtain the current sampling value set Iu of the second phase and the current sampling value set Iv of the third phase. The recorded sets Iu and Iv are compared with preset thresholds in turn. The number of current sampling values ​​in sets Iu and Iv that are greater than the preset thresholds, Nu and Nv, are recorded respectively. If either Nu or Nv has less than two values, the three-phase permanent magnet motor is considered to be missing a phase; otherwise, the three-phase permanent magnet motor is determined to be not missing a phase, and the normal start-up process is entered.

[0077] The determination of a phase loss in the three-phase permanent magnet motor includes the following detailed conditions: If the number of times the current sampling value of the second phase and the current sampling value of the third phase are greater than a preset threshold is less than 2, that is, Nu and Nv are both less than 2, then the three-phase permanent magnet motor is determined to be missing a phase or the first phase is missing a phase; if the number of times the current sampling value of the second phase is greater than the preset threshold is less than 2, that is, Nu is less than 2, then the second phase of the three-phase permanent magnet motor is determined to be missing a phase; if the number of times the current sampling value of the third phase is greater than the preset threshold is less than 2, that is, Nv is less than 2, then the third phase of the three-phase permanent magnet motor is determined to be missing a phase; otherwise, if Nu and Nv are both greater than 2, then the three-phase permanent magnet motor is determined to be not missing a phase and enters the normal start-up process.

[0078] If it is not necessary to determine which specific phase of the three-phase permanent magnet motor is missing, then if the number of current sampling values ​​of any phase of the three-phase permanent magnet motor that are greater than a preset threshold is less than 2, then the three-phase permanent magnet motor is determined to be missing a phase.

[0079] In another embodiment of the present invention, the present invention provides a phase loss detection system for a three-phase permanent magnet motor, including a control module, a first acquisition module, a second acquisition module, a first storage module, a second storage module, and a judgment module. A control module is connected to the three-phase permanent magnet motor and the upper arm, lower arm, upper arm, lower arm, upper arm, and lower arm of the first phase, the third phase, and the third phase, respectively; it is used to output control signals to control the operation of the three-phase permanent magnet motor. A first acquisition module is connected to the second phase of the three-phase permanent magnet motor and is used to acquire the current of the second phase of the three-phase permanent magnet motor. A second acquisition module is connected to the third phase of the three-phase permanent magnet motor and is used to acquire the current of the third phase of the three-phase permanent magnet motor. A first storage module is connected to the first acquisition module and is used to store the current sampling values ​​acquired by the first acquisition module. A second storage module is connected to the second acquisition module and is used to store the current sampling values ​​acquired by the second acquisition module. A judgment module is built into the control module and is used to compare the current sampling values ​​stored in the first and second storage modules with preset thresholds to determine whether the three-phase permanent magnet motor is missing a phase.

[0080] Specifically, such as Figure 7 As shown in another embodiment of the present invention, a phase loss detection system for a three-phase permanent magnet motor includes a control module 51, a first acquisition module 52, a second acquisition module 53, a first storage module 54, a second storage module 55, and a judgment module 56. The control module is connected to the three-phase permanent magnet motor and the upper arm, lower arm, upper arm, lower arm, upper arm, and lower arm of the first phase, the third phase, and the third phase, respectively; it is used to output control signals to control the operation of the three-phase permanent magnet motor. The first acquisition module is connected to the second phase of the three-phase permanent magnet motor and is used to acquire the current of the second phase of the three-phase permanent magnet motor. The second acquisition module is connected to the third phase of the three-phase permanent magnet motor and is used to acquire the current of the third phase of the three-phase permanent magnet motor. The first storage module is connected to the first acquisition module and is used to store the current sampling values ​​acquired by the first acquisition module. The second storage module is connected to the second acquisition module and is used to store the current sampling values ​​acquired by the second acquisition module. The judgment module is built into the control module and is used to compare the current sampling values ​​stored in the first storage module and the current sampling values ​​stored in the second storage module with preset thresholds to determine whether the three-phase permanent magnet motor is missing a phase.

[0081] More specifically, in this embodiment of the invention, the first storage module and the second storage module are two separate storage modules, respectively used to store the currents collected by the first acquisition module and the second acquisition module. In another embodiment of the invention, the first storage module and the second storage module may be a single storage module used to store the currents collected by the first acquisition module and the second acquisition module; this will not be elaborated further here.

[0082] More specifically, the judgment module can have various implementation forms. In one embodiment of the present invention, the judgment module is built into the control module. In another embodiment of the present invention, the control module can exist independently of the control module and can be flexibly set according to the actual use scenario. This will not be explained in detail here.

[0083] In one embodiment of the present invention, the control module is used to output a drive signal to control the three-phase permanent magnet motor to enter a pre-start working state. In the pre-start working state, the drive signal controls the lower bridge arm switch of the first phase of the three-phase permanent magnet motor to be turned on, so as to charge the bootstrap capacitor of the three-phase permanent magnet motor drive circuit. After the bootstrap capacitor is charged, the drive signal controls the upper bridge arm switch of the first phase, the lower bridge arm switch of the second phase, and the lower bridge arm switch of the third phase of the three-phase permanent magnet motor to be turned on for a preset time period and then turned off.

[0084] In one embodiment of the present invention, the first acquisition module is used to acquire the current flowing from the first phase to the second phase of the three-phase permanent magnet motor in the circuit and store it in the first storage module; the second acquisition module is used to acquire the current flowing from the first phase to the third phase of the three-phase permanent magnet motor in the circuit and store it in the second storage module. The judgment module is connected to the first storage module and the second storage module respectively, and is used to compare the current sampling value stored in the first storage module and the current sampling value stored in the second storage module with preset thresholds in sequence to determine whether the three-phase permanent magnet motor is missing a phase.

[0085] Specifically, such as Figure 7As shown, the control module outputs a drive signal to control the three-phase permanent magnet motor to enter a pre-start working state. In the pre-start working state, the drive signal controls the lower bridge arm switch of the first phase (W phase) of the three-phase permanent magnet motor to turn on, charging the bootstrap capacitor of the three-phase permanent magnet motor drive circuit. After the bootstrap capacitor is charged, the drive signal controls the upper bridge arm switch of the first phase (W phase), the lower bridge arm switch of the second phase (U phase), and the lower bridge arm switch of the third phase (V phase) of the three-phase permanent magnet motor to turn on for a preset time period and then turn off. During the preset time period, the upper bridge arm switch of the first phase (W phase), the lower bridge arm switch of the second phase (U phase), and the lower bridge arm switch of the third phase (V phase) of the three-phase permanent magnet motor are all turned on to form a circuit loop, generating current that flows from the first phase (W phase) of the three-phase permanent magnet motor to the second phase (U phase) and the third phase (V phase) of the three-phase permanent magnet motor, respectively. During the preset time period, the current of the second phase (U phase) and the current of the third phase (V phase) of the three-phase permanent magnet motor are collected. If the current of the second phase (U phase) or the current of the third phase (V phase) is less than a preset threshold, it is determined that the three-phase permanent magnet motor is missing a phase; otherwise, there is no phase loss.

[0086] In another embodiment, the instruction of whether the three-phase permanent magnet motor is missing a phase, as determined by the judgment module, is transmitted to the control module. The control module is then used to control the three-phase permanent magnet motor to perform corresponding processing according to the transmitted instruction. For example, if the three-phase permanent magnet motor is missing a phase, a fault code is generated and the motor enters the system fault protection state; otherwise, the motor enters the normal start-up process.

[0087] In one embodiment of the present invention, an electronic device is provided, including a processor and a memory, wherein the memory is used to store a computer program; the processor is connected to the memory and is used to execute the computer program stored in the memory, so that the electronic device performs the phase loss detection method of the three-phase permanent magnet motor described above.

[0088] Specifically, such as Figure 8 As shown in the figure, an electronic device according to an embodiment of the present invention includes a processor 61 and a memory 62. The processor and the memory can be connected and controlled via a bus. The memory is used to store computer programs. The processor is connected to the memory and is used to execute the computer programs stored in the memory so that the electronic device performs the phase loss detection method described above.

[0089] The memory may include high-speed random access memory, and may also include non-transitory memory, such as ROM, RAM, magnetic disks, USB flash drives, memory cards, or optical discs, and other media capable of storing program code. In some embodiments, the memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the electronic device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0090] Preferably, the processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0091] In one embodiment of the present invention, a computer-readable storage medium is also provided. Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing a processor. The program can be stored in a computer-readable storage medium, which is a non-transitory medium, such as random access memory, read-only memory, flash memory, hard disk, solid-state drive, magnetic tape, floppy disk, optical disk, and any combination thereof. The storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., digital video disc (DVD)), or a semiconductor medium (e.g., solid-state drive (SSD)).

[0092] In summary, the phase loss detection method, system, medium, and electronic equipment for a three-phase permanent magnet motor described in this invention only requires the three-phase permanent magnet motor to generate a single voltage pulse, reliably detecting phase loss faults without requiring the motor to rotate. The method is simple and reliable. The hardware circuit design employs dual-resistor current sampling and eliminates the need for speed and position sensors, saving costs. It exhibits strong anti-interference capabilities; when a voltage pulse is generated, the detectable current value is relatively large, far exceeding sampling errors and static interference. The entire detection process is very fast, requiring no complex coordinate changes or PWM control; the voltage pulse duration is controlled at the microsecond level, resulting in virtually imperceptible start-up delay. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial applicability.

[0093] The descriptions of the processes or structures corresponding to the above figures each have their own emphasis. For parts of a process or structure that are not described in detail, please refer to the relevant descriptions of other processes or structures.

[0094] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for open-phase detection of a three-phase permanent magnet motor, characterized in that, The open-phase detection method comprises: outputting a driving signal to control the three-phase permanent magnet motor to enter a pre-start working state; in the pre-start working state, the three-phase permanent magnet motor is started but has not reached a full-speed rotating state; in the pre-start working state, the driving signal controls a first-phase lower bridge arm switch tube of the three-phase permanent magnet motor to be turned on and then turned off after a delay, so as to charge a bootstrap capacitor of a driving circuit of the three-phase permanent magnet motor; after the bootstrap capacitor is charged, the driving signal controls a first-phase upper bridge arm switch tube, a second-phase lower bridge arm switch tube and a third-phase lower bridge arm switch tube of the three-phase permanent magnet motor to be turned on for a preset time period and then turned off; in the preset time period, the first-phase upper bridge arm switch tube, the second-phase lower bridge arm switch tube and the third-phase lower bridge arm switch tube of the three-phase permanent magnet motor are all turned on to form a circuit loop, so that a current flows from the first phase of the three-phase permanent magnet motor to the second phase and the third phase of the three-phase permanent magnet motor respectively; in the preset time period, the current of the second phase and the current of the third phase of the three-phase permanent magnet motor are collected; if the current of the second phase or the current of the third phase is less than a preset threshold value, it is determined that the three-phase permanent magnet motor is open-phase, otherwise, it is not open-phase.

2. The phase deficiency detection method according to claim 1, characterized by Further comprising: the time length of the preset time period is T=L*I / (V-R*I); wherein, L is an inductance parameter of the three-phase permanent magnet motor, I is a current value expected to be reached by the three-phase permanent magnet motor, V is a voltage value of a direct current bus of the three-phase permanent magnet motor driver, and R is a resistance of the three-phase permanent magnet motor.

3. The phase deficiency detection method of claim 1, wherein if the current of the second phase or the current of the third phase is less than a preset threshold value, it is determined that the three-phase permanent magnet motor is open-phase, comprising: if the current of the second phase is less than the preset threshold value, and the current of the third phase is not less than the preset threshold value, it is determined that the second phase of the three-phase permanent magnet motor is open-phase; if the current of the third phase is less than the preset threshold value, and the current of the second phase is not less than the preset threshold value, it is determined that the third phase of the three-phase permanent magnet motor is open-phase; if the current of the second phase and the current of the third phase are both less than the preset threshold value, it is determined that the first phase of the three-phase permanent magnet motor is open-phase.

4. The phase deficiency detection method of claim 1, wherein Further comprising: in the preset time period, the current of the second phase of the three-phase permanent magnet motor is collected multiple times to obtain multiple second-phase current sampling values; if at least two of the multiple second-phase current sampling values are greater than the preset threshold value, it is determined that the second phase of the three-phase permanent magnet motor is not open-phase; otherwise, it is determined that the second phase of the three-phase permanent magnet motor is open-phase.

5. The phase failure detection method of claim 1, wherein Further comprising: in the preset time period, the current of the third phase of the three-phase permanent magnet motor is collected multiple times to obtain multiple third-phase current sampling values; if at least two of the multiple third-phase current sampling values are greater than the preset threshold value, it is determined that the third phase of the three-phase permanent magnet motor is not open-phase; otherwise, it is determined that the third phase of the three-phase permanent magnet motor is open-phase.

6. A system for open-phase detection of a three-phase permanent magnet motor, characterized by comprising: A control module is connected with the three-phase permanent magnet motor and the upper bridge arm of the first phase, the lower bridge arm of the first phase, the upper bridge arm of the second phase, the lower bridge arm of the second phase, the upper bridge arm of the third phase and the lower bridge arm of the third phase of the three-phase permanent magnet motor respectively; The control module is used for outputting a control signal to control the three-phase permanent magnet motor to work; A first acquisition module is connected with the second phase of the three-phase permanent magnet motor and is used for acquiring the current of the second phase of the three-phase permanent magnet motor; A second acquisition module is connected with the third phase of the three-phase permanent magnet motor and is used for acquiring the current of the third phase of the three-phase permanent magnet motor; A first storage module is connected with the first acquisition module and is used for storing the current sampling value acquired by the first acquisition module; A second storage module is connected with the second acquisition module and is used for storing the current sampling value acquired by the second acquisition module; A judging module is built in the control module and is used for comparing the current sampling value stored by the first storage module and the current sampling value stored by the second storage module with a preset threshold value respectively to determine whether the three-phase permanent magnet motor is open-phase; The control module is used for outputting a driving signal to control the three-phase permanent magnet motor to enter a pre-start working state; in the pre-start working state, the driving signal controls the lower bridge arm switch tube of the first phase of the three-phase permanent magnet motor to be turned on to charge the bootstrap capacitor of the driving circuit of the three-phase permanent magnet motor; after the bootstrap capacitor is charged, the driving signal controls the upper bridge arm switch tube of the first phase, the lower bridge arm switch tube of the second phase and the lower bridge arm switch tube of the third phase of the three-phase permanent magnet motor to be turned on for a preset time period and then turned off; the pre-start working state is that the three-phase permanent magnet motor is started but has not reached a full-speed rotating state.

7. The open phase detection system of claim 6, wherein, The first acquisition module is used for acquiring the current flowing from the first phase to the second phase in the driving circuit of the three-phase permanent magnet motor and saving the current in the first storage module; The second acquisition module is used for acquiring the current flowing from the first phase to the third phase in the driving circuit of the three-phase permanent magnet motor and saving the current in the second storage module; The judging module is connected with the first storage module and the second storage module respectively and is used for comparing the current sampling value stored by the first storage module and the current sampling value stored by the second storage module with a preset threshold value in sequence to determine whether the three-phase permanent magnet motor is open-phase. The computer program is executed by a processor to implement the open-phase detection method in any one of claims 1 to 5.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that, The open-phase detection device comprises at least one processor and a memory; 9. An electronic device, comprising: The memory is used for storing a computer program; The processor is connected with the memory and is used for executing the computer program stored in the memory to enable the open-phase detection device to execute the open-phase detection method in any one of claims 1 to 5. ​

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