Fault diagnosis method and system for Hall position sensor of multiphase brushless direct current motor

Abstract

The invention discloses a fault diagnosis method and system for a Hall position sensor of a multi-phase brushless direct current motor. The fault diagnosis method comprises the following steps: defining a fault detection and positioning mark of a Hall position signal, and collecting the magnitude of current of each phase of the multi-phase brushless direct current motor and the signal of the Hall position sensor in real time; according to the collected Hall position signal, judging whether a condition of inconsistent time sequence or leading or lagging of the position signal exists or not, and if yes, letting hdetx = 1; extracting the current value of each phase of the motor collected within a preset threshold tmax time, judging whether a current abrupt change condition exists or not, and if the current abrupt change condition exists, enabling hdetx to be equal to 1; and counting and outputting the position and fault characteristics of the Hall position sensor of which the hdetx is equal to 1.

Description

Technical Field

[0001] The present invention relates to the field of multiphase motor drive control, and particularly to a method and system for fault diagnosis of Hall position sensors of a multiphase brushless DC motor. Background Art

[0002] Motors are indispensable devices in industrial production and technological development. The progress of technology and the needs of industrial production have further expanded the application fields of motor systems. With the increasing demands for low voltage and high power, etc., traditional three-phase motors are already difficult to meet the actual production and innovative engineering needs. Especially in the integrated power system of ships, large-capacity motors play a crucial role in the electric propulsion system. Compared with traditional three-phase motor drive systems, multiphase motors have advantages such as small torque ripple, high control freedom, and strong fault tolerance. These advantages mean that multiphase motor drive systems are more capable of meeting a wide range of application requirements. To give full play to the advantages of advanced multiphase motors, a good control method plays a crucial role.

[0003] Brushless DC motors need to control the conduction sequence and conduction time of each phase through position sensors to achieve precise control of the output torque. Correct processing of the position signal can ensure that the motor commutes at the correct position, enabling the motor to operate according to a predetermined target. Therefore, the position signal is very important. In multiphase motor drive systems, pulse width modulation and position sensors are still used to achieve precise current control and commutation. It is precisely relying on the precise position feedback provided by the position sensor (such as a Hall position sensor) at every instant of the rotor rotation that its efficient rotational motion can be achieved. The diagnostic methods for Hall position sensor faults mainly include fault diagnosis based on the timing of the position signal, the lead or lag of the position signal, and current mutations, etc. However, in actual operation, due to various reasons such as harsh environments and vibrations, the position sensor may fail. The failure of the position sensor will cause the commutation logic of the motor drive system to be chaotic, resulting in a decrease in the motor output torque and even the inability to operate normally. Therefore, in order to improve the reliability of multiphase brushless DC motor drive systems, it is necessary to conduct research on the fault diagnosis of Hall position sensors.

[0004] CN106411190A discloses a fault-tolerant control method applicable to Hall sensors of multiphase permanent magnet brushless DC motors. This method analyzes the relationship between error codes and normal codes to keep the system running stably even in the case of a small number of Hall sensor faults. Summary of the Invention

[0005] The object of the present invention is to provide a method and system for diagnosing faults of Hall position sensors of a multi-phase brushless DC motor. The diagnosis method can judge faults through various ways such as the timing of position signals, the lead or lag of position signals, and current mutations, and can effectively distinguish different types of Hall position sensor faults, such as timing faults, lead or lag faults, current mutation faults, etc., and perform positioning.

[0006] The object of the present invention is achieved by the following technical solutions:

[0007] The first aspect of the present invention discloses a method for diagnosing faults of Hall position sensors of a multi-phase brushless DC motor, including:

[0008] Steps of signal acquisition and definition: Define the fault detection and positioning flag h of the Hall position signal detx , and initialize the fault detection and positioning flag h detx = 0, indicating that all Hall position sensors are fault-free; real-time collect the current magnitudes of each phase of the multi-phase brushless DC motor and the Hall position sensor signals, and use them to judge whether there are faults in the Hall position sensors respectively according to the timing of the Hall position signals, the lead or lag of the signals, and the mutation of the current values.

[0009] Steps of timing fault judgment: Extract the collected Hall position signals, and judge whether the current rotor position information is consistent with the timing table according to the motor rotation direction and the timing table of the Hall binary combination under forward / backward rotation of the motor. If they are the same, maintain the fault detection and positioning flag h detx = 0, and execute the steps of judging the lead or lag fault of the signal; otherwise, judge it as a faulty Hall position sensor according to the timing table, and set h detx = 1, and execute the steps of fault positioning and cause acquisition;

[0010] Steps of judging the lead or lag fault of the signal: Continue to judge the Hall position signal with the fault detection flag h detx = 0 in the steps of timing fault judgment, and further judge whether there is a fault according to the lead or lag of the Hall position signal; if the time difference between the ideal jump moment and the current actual jump moment exceeds the threshold range (△t min , △t max ), then judge that the Hall position sensor is faulty, and set the fault detection and positioning flag h detx = 1, and execute the steps of fault positioning and cause acquisition; otherwise, maintain h detx = 0, and execute the steps of judging current mutation;

[0011] Steps of judging current mutation: Extract the current values of each phase of the motor collected in the steps of signal acquisition and definition, and judge one by one whether any one of the current values in the specific two-phase currents corresponding to the Hall position sensor x is greater than the current diagnosis threshold i th, and the current value of another phase is zero. If not, maintain h detx = 0, execute the fault location and cause acquisition steps; if so, continue to judge whether the duration of the current mutation characteristic is less than a preset threshold △t max and greater than the motor adjustment time t s , if so, set the fault detection flag h of the Hall position sensor detx = 1, otherwise maintain h detx = 0, execute the fault location and cause acquisition steps;

[0012] Fault location and cause acquisition steps: According to the results of the timing judgment step, the signal lead or lag fault judgment step, and the current mutation judgment step, if h detx = 0, it means that the Hall position sensor labeled x is healthy; when h detx = 1, it means that the Hall position sensor labeled x is faulty, and output the position and fault characteristics of the faulty Hall position sensor.

[0013] Further, the fault characteristics include timing faults, lead or lag faults of Hall position signals, and current mutation faults.

[0014] Further, the steps of real-time collecting the current magnitudes of each phase of the multi-phase brushless DC motor and the Hall position sensor signals include: using a current sensor to collect the current values of each phase of the multi-phase brushless DC motor, and the collection time is the sampling time; using a position signal processing circuit to convert the square wave pulses generated by the Hall position sensor into signals that can be collected by the DSP, so as to collect the signals of each Hall position sensor.

[0015] Further, the selection basis of the specific two-phase currents corresponding to the Hall position sensor x in the current mutation judgment step is: in the multi-phase conduction mode of the multi-phase brushless DC motor, the corresponding Hall signal jump edge after the installation of the Hall position sensor corresponds to a specific commutation point, and the two-phase currents participating in the commutation corresponding to the specific commutation point.

[0016] Further, the timing judgment step specifically includes:

[0017] Convert the high and low levels of the Hall position signal into binary information of "1" and "0" signals respectively; represent the Hall state of the multi-phase brushless DC motor in the form of a binary combination; compare the obtained Hall state with the preset timing table of the motor's forward / backward rotation direction. If they are consistent, maintain the fault detection and location flag h detx = 0, execute the signal lead or lag fault judgment step; otherwise, determine the faulty Hall position sensor according to the timing table, and set h detx = 1, execute the fault location and cause acquisition steps.

[0018] Further, the signal lead or lag fault judgment step specifically includes:

[0019] Judging the fault detection flag h of the Hall position signal in the timing judgment step detx of the Hall position signal with h = 0, and further judging whether there is a fault according to the lead or lag of the position signal;

[0020] Recording the moment t of the last jump of each Hall position signal with h detx = 0 k-1 and the moment t of the penultimate jump k-2 , and calculating the ideal jump moment t of the Hall position signal in the normal state k * = t k-1 +(t k-1 -t k-2 );

[0021] Judging whether the time difference △t between the ideal jump moment t of the Hall position signal k * and the actual jump moment t of the current Hall signal k is greater than a preset threshold △t max or less than a preset threshold △t min , and the specific fault judgment formula is as follows:

[0022] (1 - δ)△t k-1 = △t min <t k -t k * = △t < △t max = (1 + δ)△t k-1 ;

[0023] If so, it indicates that the x - th Hall signal corresponding to it is faulty, and its fault detection flag h detx = 1, and execute the fault location and cause acquisition step; otherwise, maintain the fault detection and location flag h detx = 0, and execute the current mutation judgment step.

[0024] Further, in the signal lead or lag fault judgment step and the current mutation judgment step, the preset thresholds △t max and △t min are determined according to the time difference △t k-1 between the moment t of the last jump of the Hall position signal k-2 and the moment t of the penultimate jump k-1 , and the specific formula is:

[0025]

[0026] In the formula, δ is a preset constant, taking a positive value between 0 and 1.

[0027] Furthermore, in the signal leading or lagging fault judgment step and the current mutation judgment step, the motor adjustment time t s refers to the time required for the output of the motor to stabilize from the initial state to the new steady state after a step input (such as a change in load or speed). It can be obtained by experimentally measuring the step response curve of the motor or calculated based on parameters such as the inertia and inductance of the motor through a dynamic model. The adjustment time reflects the dynamic response characteristics of the motor system, and its length depends on factors such as load inertia, rotor inertia, and winding inductance. In fault diagnosis, by setting the duration of the current mutation to be greater than the adjustment time t s , the transient change and fault characteristics can be effectively distinguished, thereby improving the accuracy of diagnosis.

[0028] Furthermore, the basis for selecting the specific two-phase current corresponding to the Hall position sensor x is as follows: in the multi-phase conduction mode of the multi-phase brushless DC motor, after the Hall position sensor is installed, the jump edge of the corresponding Hall signal corresponds to a specific commutation point, and the two-phase current participating in commutation corresponding to this specific commutation point.

[0029] The second aspect of the present invention lies in disclosing a multi-phase brushless DC motor Hall position sensor fault diagnosis system, including a signal acquisition and definition unit, a timing judgment fault unit, a signal leading or lagging fault judgment unit, a current mutation judgment fault unit, and a fault location and cause acquisition unit;

[0030] The signal acquisition and definition unit is used to define and initialize the fault detection and location flags of the Hall position signal; collect the phase current values of the multi-phase brushless DC motor using a current sensor, and convert the square wave pulse generated by the Hall position sensor into a signal that can be collected by the DSP using a position signal processing circuit, so as to collect each Hall position sensor signal;

[0031] The timing judgment fault unit is used to judge whether there is a timing fault according to the Hall position signal collected by the signal acquisition and definition unit. If the current rotor position information is consistent with the timing table, the fault detection and location flag h detx = 0 is maintained. Otherwise, it is determined that it is a faulty Hall position sensor, and h detx = 1;

[0032] The signal leading or lagging fault judgment unit is used to judge the Hall position signal with the fault detection and location flag h detx = 0 in the timing judgment fault unit. If the time difference between the ideal jump moment and the current actual jump moment exceeds the threshold range (△t min , △t max) If so, it is determined that the Hall position sensor has a fault, and the fault detection and location flag h detx is set to 1; otherwise, h detx is maintained at 0. The current mutation fault judgment unit is used to judge whether there is a current mutation fault according to the current values of each phase of the motor collected by the signal acquisition and definition unit. If there is a current mutation fault, it continues to judge whether the duration of the current mutation feature is less than a preset threshold △t max and greater than the motor adjustment time t s . If so, the fault detection flag h detx of the Hall position sensor is set to 1; otherwise, h detx is maintained at 0.

[0033] The fault location and cause acquisition unit is used to obtain the position and fault characteristics of the Hall position sensor with h detx = 1 according to the results of the timing judgment fault unit, the signal lead or lag fault judgment unit, and the current mutation judgment fault unit.

[0034] A device, the device includes a processor, and the processor is used to process the method for diagnosing faults of the Hall position sensor of the multiphase brushless DC motor.

[0035] Compared with the prior art, the beneficial effects brought by the technical solution of the present invention are:

[0036] The method for diagnosing faults of the Hall position sensor of the multiphase brushless DC motor can detect the faults of the Hall position sensor in a timely and accurate manner, ensuring the normal operation of the brushless DC motor; comprehensively judging faults through multiple methods such as the timing of the position signal, the lead or lag of the position signal, and current mutation, with high diagnostic accuracy; can effectively distinguish different types of Hall position sensor faults, such as timing faults, lead or lag faults, current mutation faults, etc., and perform positioning; moreover, by defining the fault detection and location flag, it is convenient to judge the fault situation of each Hall position sensor, and the diagnostic result is intuitive and clear. Description of the Drawings

[0037] Figure 1 is the equivalent circuit diagram of the nine-phase brushless DC motor provided by the embodiment of the present invention;

[0038] Figure 2 is the schematic diagram of the Hall disk structure provided by the embodiment of the present invention;

[0039] Figure 3 is the schematic diagram of the current mutation fault before and after the fault provided in step four occurs in the first Hall position sensor in the embodiment of the present invention;

[0040] Figure 4This is the flowchart of the method for diagnosing faults in the position sensor of the multiphase brushless DC motor of the present invention. Detailed implementation manners

[0041] To make the objectives, technical solutions, beneficial effects and remarkable progress of the embodiments of the present invention clearer, the following describes the technical solutions in the embodiments of the present invention clearly and completely with reference to the accompanying drawings provided in the examples of the present invention. Obviously, all the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0042] In the description of the present application, unless otherwise clearly specified and limited, the terms "first", "second", "third" are only used for the purpose of description and cannot be understood as indicating or implying relative importance; the term "plurality" means two or more; unless otherwise specified or stated, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0043] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0044] The present invention is applicable to the fault diagnosis of the position sensor of a multiphase brushless DC motor, and is a Hall position sensor fault diagnosis method based on position signals and current signals, which can realize independent and rapid fault diagnosis of each position sensor, help to switch to a fault-tolerant strategy in time, and reduce the impact of faults on system performance.

[0045] This embodiment selects a nine-phase brushless DC motor drive system as an application example, and its specific connection method is as Figure 1 shown. This circuit is a conventional circuit in the art and will not be introduced in detail here. The Hall position sensor and disk structure diagram used in the nine-phase brushless DC motor are shown in Figure 2. Nine Hall elements are evenly distributed on the disk. According to the Hall position signals output by the nine Hall position sensors, the 360° electrical angle is divided into 18 sectors, and each sector corresponds to an electrical angle of 20°. This design significantly improves the accuracy of detecting the position of the motor rotor.

[0046] AsFigure 4 As shown, the nine-phase brushless DC motor position sensor fault diagnosis method includes the following steps:

[0047] Step 1: Define the fault detection and location flag h for the Hall position signal detx , and initialize the fault detection and location flag h detx = 0, indicating that all Hall position sensors are fault-free; and obtain the total number of Hall position sensors n = 9; where x represents the label of the Hall position sensor, and x = {1, 2, 3,..., 9}.

[0048] Step 2: Real-time collect the current magnitudes of each phase of the multi-phase brushless DC motor and the Hall position sensor signals. Specifically, use a current sensor to collect the current values of each phase of the multi-phase brushless DC motor, and the collection time is the sampling time; and use a position signal processing circuit to convert the square wave pulses generated by the Hall position sensors into signals that can be collected by the DSP, so as to collect the signals of each Hall position sensor;

[0049] Step 3: Judge faults according to the timing of the Hall position signals collected in Step 2. Specifically, it includes:

[0050] S301: Convert the high and low levels of the Hall position signal into "1" and "0" signals respectively;

[0051] S302: Determine the current rotor position information according to the binary combination s of the 1-9 Hall position signals; the binary combination s of the nine-phase brushless DC motor can be expressed as

[0052] s = 256·H 1 + 128·H 2 + 64·H 3 + 32·H 4

[0053] + 16·H 5 + 8·H 6 + 4·H 7 + 2·H 8 + 1·H 9

[0054] In the formula, s is the Hall state, and H 1 to H 9 represent the Hall position signals corresponding to the 9 Hall position sensors (the first Hall position sensor, the second Hall position sensor... the ninth Hall position sensor) respectively.

[0055] S303: Preset the correspondence table between the rotor sectors and the Hall position signals according to the binary combination s of the Hall signals in the healthy state of the Hall position sensors as follows:

[0056] Table 1 Correspondence Table between Rotor Sector and Hall Position Signal

[0057] sector Hall signal Hall state s 0°～20° 101010101 341 20°～40° 101010100 340 40°～60° 101010110 342 60°～80° 101010010 338 80°～100° 101011010 346 100°～120° 101001010 330 120°～140° 101101010 362 140°～160° 100101010 298 160°～180° 110101010 426 180°～200° 010101010 170 200°～220° 010101011 171 220°～240° 010101001 169 240°～260° 010101101 173 260°～280° 010100101 165 280°～300° 010110101 181 300°～320° 010010101 149 320°～340° 011010101 213 340°～360° 001010101 85

[0058] As can be seen from Table 1, when there is no fault, looking from the head end of the motor, in the case of the rotor running counterclockwise, the next value of the Hall state s value of 341 should be 340. If not, it can be judged that there is a timing fault in the position signal; if there is a timing fault in the x-th Hall position sensor and the x-th signal is inconsistent with the timing table, it is determined that the x-th Hall position signal is faulty, and its fault detection flag h detx = 1; otherwise, maintain h detx = 0.

[0059] Step 4. Determine whether there is a signal advance or lag fault in the Hall position signal with h detx = 0

[0060] S401: Extract the Hall position signal with the fault detection flag h detx = 0 in Step S303;

[0061] Record the moment t detx of the last jump of each Hall position signal with h k-1 = 0 and the moment t k-2 of the penultimate jump, and calculate the ideal jump moment t k * = t k-1 +(t k-1 -t k-2 );

[0062] S402: Determine whether the time difference △t between the ideal jump moment t k * of the Hall position signal and the actual jump moment t k of the current Hall signal is greater than the preset threshold △t max or less than the preset threshold △t min , and the specific fault judgment formula is as follows:

[0063] (1 - δ)△t k-1 = △t min <t k -t k * = △t < △t max = (1 + δ)△t k-1 ;

[0064] If so, it indicates that the corresponding x-th Hall signal is faulty, and its fault detection flag h detx = 1; otherwise, maintain h detx= 0, perform the next operation.

[0065] Among them, the preset threshold Δt max and the threshold Δt min are determined according to the time t k-1 of the last jump of the Hall position signal and the time t k-2 of the jump before the last one, and the time difference Δt k-1 is determined. The specific formula is:

[0066]

[0067] In the formula, δ is a preset constant, taking a positive value between 0 and 1.

[0068] Step Five: Judge whether there is a fault according to the current mutation of the phase current values collected in Step Two. Specifically, it includes:

[0069] S501: Obtain the phase current signals of the motor collected in Step Two, and preset the current reference value i ref .

[0070] S502: The fault diagnosis current threshold i th is obtained as follows:

[0071] The definition basis of the specific current characteristic judgment flag corresponding to the above Hall position sensor failure is determined according to the relationship between the conducting phase windings of the nine-phase brushless DC motor and the corresponding Hall signals, as shown in the following table:

[0072] Table 2 Relationship between conducting phase windings and corresponding Hall signals in the eight-phase conduction mode of the nine-phase brushless DC motor

[0073]

[0074]

[0075] Taking the failure of the first Hall position sensor as an example, it can be seen from Table 2 that the jump of the Hall signal corresponding to the first Hall position sensor corresponds to the commutation of the A 1 phase winding and the A 9 phase winding. Thus, the current characteristic judgment flag of the first Hall position sensor is determined as shown in the following formula

[0076]

[0077] In the formula, h det1 is the current fault characteristic judgment flag of the first Hall position sensor. A judgment flag of 1 indicates that the first Hall position sensor fails, and the fault diagnosis current threshold i th = (1 + δ A )iref , δ A and ε A are preset constants greater than zero, used to ensure the robustness of the detection method. i ref is the given current value of the current loop.

[0078] When a current mutation fault occurs in the first Hall position sensor, the sum of the forward conduction current and the reverse conduction current should be zero under normal conditions. However, the fault will cause the amplitude of the phase current i A9 to increase, which will cause the current in the A 9 phase windings that are also reverse-conducting with the A 3 , A 5 , A 7 phase windings to decrease, while the current in the forward-conducting A 2 , A 4 , A 6 , A 8 phase windings increases. In a multi-phase motor, since the current changes in other phases are relatively average, the change in the phase current i A9 is particularly significant. At the same time, since the A 1 phase winding is not conducting, its phase current i A1 is zero. At this time, the current situation before and after the fault is as shown in Figure 3 . These changes enable us to accurately locate the faulty Hall position sensor.

[0079] S503: Determine whether the current mutation characteristics are satisfied according to the fault diagnosis current threshold i th obtained in S502. That is, when a current mutation fault occurs in the first Hall position sensor, that is, when any one of the phase current values in the specific two-phase currents corresponding to the first Hall position sensor is greater than the fault diagnosis current threshold i th , and the other phase current value is zero, it indicates that a current mutation has occurred in the x-th Hall signal fault. Let its fault detection flag h detx = 1, and execute S504; otherwise, maintain h detx = 0, and execute step six.

[0080] Among them, the selection basis for the specific two-phase currents corresponding to the Hall position sensor x is: in the multi-phase conduction mode of a multi-phase brushless DC motor, the Hall signal jump edge corresponding to the installed Hall position sensor corresponds to a specific commutation point, and the two-phase currents participating in commutation corresponding to this specific commutation point.

[0081] S504: When the fault detection flag h detx = 1 after S503, that is, the current mutation characteristics of the Hall position sensor are detected, start timing of time t; the time t refers to the duration of the current mutation characteristics; if the time t is less than the preset threshold Δt max and greater than the motor adjustment time ts Set the fault detection flag h detx to 1; otherwise, maintain the fault detection flag h detx at 0. The motor adjustment time t s is determined by experimentally measuring the step response curve of the motor and observing the time when the output enters the steady-state value error band.

[0082] Step Six: Determine the fault diagnosis result according to the fault flag variable h corresponding to each Hall position sensor obtained in Steps Three to Five. detx When h detx = 0, it indicates that the Hall position sensor labeled x is healthy; when h detx = 1, it indicates that the Hall position sensor labeled x is faulty; output the diagnosis result through the host computer to locate the position and fault condition of the faulty Hall position sensor for subsequent processing.

[0083] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or equivalently replace some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Non-essential improvements, adjustments, or replacements made by those skilled in the art according to the content of this specification all fall within the scope protected by the present invention.

Claims

1. A multi-phase brushless DC motor Hall position sensor fault diagnosis method, comprising: Signal acquisition and definition steps: define the fault detection and positioning flag h of the Hall position signal detx , initialize the fault detection and location flag h detx =0, indicating that all Hall position sensors are fault-free; Real-time acquisition of the current magnitude of each phase of the multi-phase brushless DC motor and the Hall position sensor signal, used to determine whether the Hall position sensor is faulty according to the timing of the Hall position signal, signal advance or lag, and sudden change of the current value; Timing judgment step: extract the collected Hall position signal, and judge whether the current rotor position information is consistent with the timing table according to the motor direction and the Hall binary combination under the motor forward / reverse rotation timing table. If they are the same, maintain the fault detection and positioning flag h detx =0, execute the signal leading or lagging fault judgment step; Otherwise, it is determined that it is a faulty Hall position sensor according to the timing table, and h detx =1, execute the fault location and cause acquisition steps; Signal advance or lag fault judgment step: judge the fault detection mark h of the Hall position signal in the timing fault judgment step detx = 0 Hall position signal; if the time difference between the ideal jump time and the current actual jump time exceeds the threshold range (△t min , △t max ), then the Hall position sensor is judged to be faulty, and the fault detection and positioning flag h detx =1, execute the fault location and cause acquisition steps; otherwise, maintain h detx =0, execute the current mutation judgment step; Current mutation judgment step: extract the current values ​​of each phase of the motor collected in the signal acquisition and definition steps, and judge one by one whether any phase current value in the specific two-phase current corresponding to the Hall position sensor is greater than the current diagnosis threshold i th , and the other phase current value is zero, if not, maintain h detx =0, perform the fault location and cause acquisition steps; if yes, continue to determine whether the duration of the current mutation feature is less than the preset threshold △t max And greater than the motor adjustment time t s If yes, set the fault detection flag h of the Hall position sensor detx =1, otherwise maintain h detx =0, execute the fault location and cause acquisition steps; Fault location and cause acquisition steps: According to the results of the timing judgment step, the signal advance or lag fault judgment step and the current mutation judgment step, if h detx = 0, it means that the Hall position sensor labeled x is healthy; when h detx When =1, it means that the Hall position sensor labeled x is faulty, and the position and fault characteristics of the faulty Hall position sensor are output.

2. The multi-phase brushless DC motor Hall position sensor fault diagnosis method according to claim 1, characterized in that: The fault characteristics include timing fault, leading or lagging fault of the Hall position signal, and current sudden change fault.

3. The multi-phase brushless DC motor Hall position sensor fault diagnosis method according to claim 1, characterized in that: The steps of real-time acquisition of the current magnitude of each phase of a multi-phase brushless DC motor and the Hall position sensor signal include: using a current sensor to acquire the current value of each phase of the multi-phase brushless DC motor, and the acquisition time is a sampling time; using a position signal processing circuit to convert the square wave pulse generated by the Hall position sensor into a signal that can be acquired by a DSP, thereby acquiring each Hall position sensor signal.

4. The multi-phase brushless DC motor Hall position sensor fault diagnosis method according to claim 1, characterized in that: The basis for selecting the specific two-phase current corresponding to the Hall position sensor x described in the current mutation judgment step is: in the multi-phase conduction mode of the multi-phase brushless DC motor, the corresponding Hall signal jump edge after the Hall position sensor is installed corresponds to a specific switching point, and the specific switching point corresponds to the two-phase current participating in the switching.

5. The multi-phase brushless DC motor Hall position sensor fault diagnosis method according to claim 3, characterized in that: The timing determination step specifically includes: Convert the high and low levels of the Hall position signal into binary information of "1" and "0" signals respectively; represent the Hall state of the multi-phase brushless DC motor in binary combination form; compare the obtained Hall state with the preset motor sequence clockwise / counterclockwise timing table, and if they are consistent, maintain the fault detection and positioning mark h detx =0; execute the signal leading or lagging fault judgment step; otherwise, set h detx =1, and determine the faulty Hall position sensor according to the timing table, and execute the fault location and cause acquisition steps.

6. The multi-phase brushless DC motor Hall position sensor fault diagnosis method according to claim 3, characterized in that: The signal leading or lagging fault judgment step specifically includes: Fault detection flag h of the Hall position signal in the timing judgment step detx = 0, further determine whether there is a fault based on the advance or lag of the position signal; Record each h detx = 0, the last time the Hall position signal jumped k-1 and the last jump time t k-2 , calculate the ideal jump time t of the Hall position signal under normal conditions k * =t k-1 +(t k-1 -t k-2 ); Determine the ideal transition time t of the Hall position signal k * The actual transition time of the current Hall signal t k Is the time difference △t greater than the preset threshold △t max Or less than the preset threshold △t min , the specific fault judgment formula is as follows: If yes, it indicates that the corresponding Hall signal No. x is faulty, and its fault detection flag h detx =1, execute the fault location and cause acquisition steps; otherwise, maintain the fault detection and location flag h detx =0, execute the current mutation judgment step.

7. The multi-phase brushless DC motor Hall position sensor fault diagnosis method according to claim 3, characterized in that: In the signal leading or lagging fault judgment step and the current sudden change judgment step, the preset threshold △t max and threshold △t min It is based on the last jump time t of the Hall position signal k-1 and the last jump time t k-2 The time difference △t k-1 Determined, the specific formula is: Wherein, δ is a preset constant, which takes a positive value between 0 and 1.

8. The multi-phase brushless DC motor Hall position sensor fault diagnosis method according to claim 3, characterized in that: The basis for selecting the specific two-phase current corresponding to the Hall position sensor x is: in the multi-phase conduction mode of the multi-phase brushless DC motor, the corresponding Hall signal jump edge after the Hall position sensor is installed corresponds to a specific switching point, and the specific switching point corresponds to the two-phase current participating in the switching.

9. A multi-phase brushless DC motor Hall position sensor fault diagnosis system, characterized in that: It includes a signal acquisition and definition unit, a timing fault judgment unit, a signal advance or lag fault judgment unit, a current mutation fault judgment unit, and a fault location and cause acquisition unit; The signal acquisition and definition unit is used to define and initialize the fault detection and positioning flags that define the Hall position signal; Using a current sensor to collect the current value of each phase of the multi-phase brushless DC motor, using a position signal processing circuit to convert the square wave pulse generated by the Hall position sensor into a signal that can be collected by the DSP, thereby collecting each Hall position sensor signal; The timing fault judgment unit is used to judge whether there is a timing fault according to the Hall position signal collected by the signal collection and definition unit. If the current rotor position information is consistent with the timing table, the fault detection and positioning flag h is maintained. detx = 0, otherwise, it is determined to be a faulty Hall position sensor, let h detx =1; The signal leading or lagging fault judgment unit is used to judge the fault detection and positioning mark h in the timing judgment fault unit detx = 0 Hall position signal, if the time difference between the ideal jump time and the current actual jump time exceeds the threshold range (△t min , △t max ), then the Hall position sensor is judged to be faulty, and the fault detection and positioning flag h detx =1 otherwise maintain h detx =0; The current mutation fault judgment unit is used to judge whether there is a current mutation fault according to the current values ​​of each phase of the motor collected by the signal acquisition and definition unit; if there is a current mutation fault, continue to judge whether the duration of the current mutation feature is less than a preset threshold value △t max And greater than the motor adjustment time t s If so, the fault detection flag h of the Hall position sensor is set to detx =1, otherwise maintain h detx =0; The fault location and cause acquisition unit is used to obtain the results of the time sequence fault judgment unit, the signal advance or lag fault judgment unit and the current mutation fault judgment unit according to the time sequence fault judgment unit, the signal advance or lag fault judgment unit and the current mutation fault judgment unit according to the time sequence fault judgment unit, the signal advance or lag fault judgment unit and the signal advance or lag ... detx =1, the position and fault characteristics of the Hall position sensor.

10. A device, characterized in that: The device includes a processor, and the processor is used to process the multi-phase brushless DC motor Hall position sensor fault diagnosis method according to any one of claims 1-8.

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