Real-time detection method for three-phase full phase dislocation sequence of permanent magnet synchronous motor

Abstract

The invention relates to the technical field of permanent magnet synchronous motor fault diagnosis, in particular to a permanent magnet synchronous motor three-phase full-fault phase sequence real-time detection method, which comprises the following steps: acquiring resistance parameters of a permanent magnet synchronous motor; judging whether the permanent magnet synchronous motor meets a three-phase full-fault phase sequence detection condition or not; when it is judged that the permanent magnet synchronous motor meets the three-phase full-fault phase sequence detection condition, whether phase sequence wiring between the motor and a driver is in a three-phase full-fault state or not is judged; recording the rotating speed Nr1 of the motor at the moment when the phase sequence wiring three-phase fully-staggered phase sequence state between the motor and the driver is judged; the duration time of the three-phase full fault state is monitored, and when the duration time of the three-phase full fault state exceeds a preset detection time threshold value, the rotating speed Nr2 of the motor is recorded; when Nr2gt; and Nr1, triggering a three-phase full phase fault sequence alarm. According to the method, whether the motor is in the three-phase full phase sequence dislocation state or not is judged through the three-phase full phase sequence dislocation formula, the detection process is simple, convenient and efficient, equipment damage and safety accidents caused by phase sequence errors can be avoided, and system safety and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motor fault diagnosis, and in particular to a real-time detection method for a permanent magnet synchronous motor three-phase full-fault phase sequence. Background Art

[0002] Permanent magnet synchronous motors are widely used in industrial drives, new energy vehicles, intelligent equipment, and other fields. In practical applications, incorrect phase sequence wiring between the motor and the drive is a common fault type and is particularly harmful. Phase mismatch can be categorized as two-phase mismatch or three-phase mismatch. A two-phase mismatch causes the motor to oscillate at its steady-state point, leading to unstable operation and abnormal vibration. A three-phase mismatch, where the U, V, and W phases are completely misaligned, causes the rotor to rotate in the opposite direction of the command, causing the motor to run in the reverse direction. Compared to a two-phase mismatch, a three-phase mismatch can cause more serious equipment damage and safety risks, such as motor reversal, current overload, drive system damage, electrical accidents, and mechanical injuries.

[0003] In the existing technology, the detection methods for phase mismatch mostly focus on non-real-time offline judgment and simple judgment through motor reversal conditions. Traditional phase sequence detection methods are mainly based on tools such as phase sequence tables. These methods require manual operation, which is not only inefficient but also unable to monitor the phase sequence status in real time. In addition, although some phase sequence detection methods based on digital circuits can realize automated detection, the recognition accuracy of three-phase fully wrong phase sequence is not high, and it is easy to make misjudgments and missed judgments. Some existing technologies have certain limitations and cannot timely and accurately identify three-phase fully wrong phase sequence. When the offline judgment fails, it is difficult to take real-time and rapid protection measures for the high-risk three-phase fully wrong state during the operation of the motor, resulting in serious safety accidents. Therefore, there is a need for a method that can accurately identify the three-phase fully wrong phase sequence in real time, so as to trigger the protection mechanism in time at the early stage of the fault during the operation process to avoid equipment damage and safety accidents. Summary of the Invention

[0004] In order to solve the technical problems existing in the prior art, the present invention provides a real-time detection method for a three-phase fully wrong phase sequence of a permanent magnet synchronous motor, which is used to perform real-time detection of a three-phase fully wrong phase sequence fault between the permanent magnet synchronous motor and the driver, thereby avoiding equipment damage and safety accidents caused by phase sequence errors and improving system safety and reliability.

[0005] The purpose of the present invention can be achieved by taking the following technical solutions:

[0006] A method for real-time detection of three-phase full-fault phase sequence of permanent magnet synchronous motor includes the following steps:

[0007] Get the resistance parameters of the permanent magnet synchronous motor;

[0008] When the permanent magnet synchronous motor enters the enabled state, the motor speed is collected in real time through the encoder, and the detection speed threshold is set. When the motor speed is greater than the preset detection speed threshold, it is determined that the permanent magnet synchronous motor meets the three-phase full phase sequence detection condition;

[0009] When it is determined that the permanent magnet synchronous motor meets the three-phase full phase sequence detection conditions, judge whether the phase sequence connection between the motor and the driver is in a three-phase full phase sequence state based on the q-axis voltage, q-axis current, motor speed and resistance parameters of the permanent magnet synchronous motor; when it is determined that the phase sequence connection between the motor and the driver is in a three-phase full phase sequence state, record the motor speed N at this time. r 1;

[0010] Monitor the duration of the three-phase full fault state. When the duration of the three-phase full fault state exceeds the preset detection time threshold, the motor speed N is recorded. r 2; when | N r 2|>|N r 1|, triggering a three-phase phase sequence error alarm.

[0011] Specifically, judging whether the phase sequence connection between the motor and the driver is in a three-phase full-fault state based on the q-axis voltage, q-axis current, motor speed, and resistance parameters of the permanent magnet synchronous motor includes:

[0012] According to the phase sequence of the three-phase full fault between the motor and the driver, the three-phase full fault phase sequence formula is calculated based on the motor stator voltage equation;

[0013] Based on the q-axis voltage, q-axis current, motor speed, and resistance parameters of the permanent magnet synchronous motor, the three-phase full-fault phase sequence formula is used to determine whether the phase sequence connection between the motor and the driver is in a three-phase full-fault state. The three-phase full-fault phase sequence formula is expressed as:

[0014] (u q * -Ri q * )(N r )<-1

[0015] Among them, u q * represents the q-axis voltage, i q * represents the q-axis current, Nr is the motor speed, and R is the resistance parameter.

[0016] Specifically, the q-axis voltage is set in real time by a program instruction of a motor drive controller, and the q-axis current is collected in real time by a current sensor.

[0017] Specifically, the detection speed threshold is 20%-100% of the rated speed of the motor.

[0018] Specifically, the detection time threshold value ranges from 1 millisecond to 100 milliseconds.

[0019] Specifically, the triggering of the three-phase full phase sequence error alarm includes: triggering the driver to shut down for protection or communicating an alarm to a host computer, automatically cutting off the power supply to the motor or prompting a fault message through a human-machine interface.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] The present invention provides a real-time detection method for a three-phase fully misaligned phase sequence in a permanent magnet synchronous motor. By collecting motor operating data in real time and setting a detection speed threshold, the permanent magnet synchronous motor is determined to meet the three-phase fully misaligned phase sequence detection condition when the motor speed exceeds the preset detection speed threshold. Based on the permanent magnet synchronous motor's q-axis voltage, q-axis current, motor speed, and resistance parameters, the method determines whether the phase sequence wiring between the motor and the driver is in a three-phase fully misaligned state. Combined with a formula representing a three-phase fully misaligned phase sequence, the method can quickly and accurately identify three-phase fully misaligned phase sequence faults, avoiding motor damage or system loss of control due to wiring errors, significantly improving system safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0023] Figure 1 1 is a flow chart of a method for real-time detection of a three-phase full-fault phase sequence of a permanent magnet synchronous motor according to an embodiment of the present invention;

[0024] Figure 2 1 is a schematic diagram showing the principle of a control method for a permanent magnet synchronous motor according to an embodiment of the present invention;

[0025] Figure 3 Schematic diagram of the phase sequence between the power line and the motor line in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is obvious that the embodiments described are only some embodiments of the present invention, not all embodiments, and the implementation of the present invention is not limited to these. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Example 1:

[0028] This embodiment provides a new method for real-time detection of a three-phase fully faulty phase sequence in a permanent magnet synchronous motor. This detection method only requires obtaining a small amount of data and can determine in real time whether the motor is in a three-phase fully faulty phase sequence state based on the corresponding relationship. By collecting motor operating data in real time and combining it with the formula that characterizes the three-phase fully faulty phase sequence, it can quickly and accurately identify three-phase fully faulty phase sequence faults, avoid motor damage or system loss of control due to wiring errors, and significantly improve system safety and reliability. The detection process is simple, does not require additional measuring instruments or hardware circuits, and has the characteristics of low cost and strong applicability.

[0029] like Figure 1 As shown, the method for real-time detection of a three-phase full-wrong phase sequence of a permanent magnet synchronous motor according to the present invention comprises the following steps:

[0030] Step 1: Obtain the resistance parameters of the permanent magnet synchronous motor.

[0031] Specifically, the permanent magnet synchronous motor resistance parameter R can be obtained from the permanent magnet synchronous motor nameplate data or offline test methods. Alternatively, the resistance between the two phases of the motor can be directly measured using a multimeter, and the resistance parameter R is half of the measurement result.

[0032] Step 2: When the permanent magnet synchronous motor enters the enabled state, the motor speed N is collected in real time through the encoder. r , set the detection speed threshold. When the motor speed is greater than the preset detection speed threshold, it is determined that the permanent magnet synchronous motor meets the three-phase full-fault phase sequence detection conditions.

[0033] like Figure 2 Figure 2 shows a schematic diagram of a control method for a permanent magnet synchronous motor. The motor controller includes an inverter power module and a microcontroller. The inverter power module converts the DC bus voltage into a three-phase AC voltage, while the microcontroller executes a real-time space vector pulse width modulation (SVPWM) algorithm to output PWM signals. The motor controller power lines have three-phase connections (A, B, and C), while the permanent magnet synchronous motor power lines have three-phase connections (U, V, and W). The motor controller power lines (A, B, and C) and the permanent magnet synchronous motor power lines (U, V, and W) must be connected in a specific phase sequence for the motor to operate properly. A three-phase full phase sequence error occurs when the phase order of the motor's three-phase power supply is completely reversed (for example, ABC becomes CAB), resulting in motor reverse rotation or abnormal torque, threatening system safety.

[0034] The Enable State of a permanent magnet synchronous motor refers to the state in which the motor control system switches the motor from a standby or disabled state to a ready state for controlled operation through specific instructions or signals. In this state, the motor driver is activated and ready to receive control instructions. When the motor enters the Enable State, the motor speed N is collected in real time through the encoder. r, motor speed N r The unit is rpm. The encoder is sampled at a period of T s The motor position signal is collected in real time. The motor controller calculates the real-time speed (unit: rpm) of the permanent magnet synchronous motor by reading the position information fed back by the encoder and combining it with the timer interrupt mechanism. The calculation formula of the real-time speed of the permanent magnet synchronous motor is:

[0035]

[0036] Where ΔN is the position increment within the sampling period, T s is the sampling time, N ppr The number of lines per encoder revolution.

[0037] The preset detection speed threshold is N th , for example, detecting the speed threshold N th It can be set to 20% of the rated speed of the motor when |Nr|>|N th |, it is determined that the three-phase full phase sequence detection condition is met. If not, the speed is continuously monitored until the condition is met. The rated speed of the motor is 1200rpm, and N is set th =240rpm, when it is detected that the speed increases to 300rpm (exceeding the threshold), it is determined that the three-phase full fault phase sequence detection condition is met, and the next step of three-phase full fault phase sequence state determination is entered.

[0038] When the motor is enabled, the stator winding generates a rotating magnetic field vector. Under the correct phase sequence, the spatial angle θ between the rotor flux and the stator magnetic field remains in dynamic equilibrium. When the phase sequence is completely wrong, the magnetic field reverses its direction of rotation, causing torque distortion.

[0039] Step 3: When it is determined that the permanent magnet synchronous motor meets the three-phase full-wrong phase sequence detection conditions, determine whether the phase sequence connection between the motor and the driver is in a three-phase full-wrong state based on the q-axis voltage, q-axis current, motor speed and resistance parameters of the permanent magnet synchronous motor; when it is determined that the phase sequence connection between the motor and the driver is in a three-phase full-wrong state, record the motor speed N at this time. r 1.

[0040] S31. According to the phase sequence of the three-phase full fault between the motor and the driver, a three-phase full fault phase sequence formula is calculated based on the motor stator voltage equation.

[0041] like Figure 3The following figure shows the phase sequence between the drive power line and the motor line. In a permanent magnet synchronous motor, the normal phase sequence between the power line and the motor line is set to UVW. The voltage phase difference between the U phase and the V phase is 120 degrees. The voltage phase difference between the V phase and the W phase is also 120 degrees. The voltage phase difference between the W phase and the U phase is also 120 degrees. The phase sequence for a three-phase full fault is: VWU and WUV. In this case, the order of the phases is swapped. VWU is equivalent to a zero point offset of 120 degrees, and WUV is equivalent to a zero point offset of -120 degrees.

[0042] The motor stator voltage equation is as follows:

[0043]

[0044] u d 、u q represents the d-axis voltage and q-axis voltage, i.e., the d-axis and q-axis components of the stator voltage, i d 、i q represents the d-axis current and q-axis current, i.e., the d-axis and q-axis components of the stator current, i d 、i q represents the synchronous inductance of the d-axis and q-axis, ω e represents the rotor electrical angular velocity (rad / s), ψ f is the magnetic linkage parameter.

[0045] In the permanent magnet synchronous motor vector control, I is usually used d =0 control strategy, that is, the component of the stator current in the direct axis direction is zero. When the current is in steady state, the value of its differential part is small, that is, in the case of normal phase sequence UVW, its given u q The simplified results are as follows:

[0046] u q ≈Ri q +ω e ψ f (3)

[0047] Taking the VWU phase sequence as an example, the d-axis current i is collected in real time by the current sensor. d * and q-axis current i q * , and the actual current i d and i q Does not correspond, at this time the actual current i d and i q as follows:

[0048]

[0049] The d-axis voltage u given by the motor drive controller program d* and q-axis voltage u q * , and the actual u d and u q It also does not correspond to the given u d * and u q * as follows:

[0050]

[0051] Substituting formula (4) into formula (2), we get u d and u q Substituting it into formula (5), the simplified result is as follows:

[0052]

[0053] Normally, in the permanent magnet synchronous motor vector control, I d =0 control strategy, that is, the component of the stator current in the direct axis direction is zero. d and L q The values of u are close and the differential value is small when the current is in steady state. Therefore, given u q * The simplified results are as follows:

[0054]

[0055] Continuing to simplify, we can get:

[0056]

[0057] Where p is the number of motor pole pairs.

[0058] Based on the above simplification results, the three-phase full-fault phase sequence formula for judging whether the phase sequence connection between the motor and the driver is in a three-phase full-fault state is obtained as follows:

[0059]

[0060] Among them, i q * Indicates the q-axis current collected by the current sensor in real time, u q * It represents the q-axis voltage given by the motor drive controller program, Nr is the motor speed, and R is the resistance parameter.

[0061] Specifically, the motor speed Nr needs to satisfy the following inequality, and the above inequality (9) holds:

[0062]

[0063] Similarly, the results of WUV phase sequence are also consistent.

[0064] The normal phase sequence can be derived from the following inequality:

[0065]

[0066] Among them, the following inequality needs to be satisfied, and the above inequality (11) holds:

[0067]

[0068] By comparing the derivation results of normal phase sequence and three-phase full-fault phase sequence, it can be concluded that when the following inequality is satisfied

[0069]

[0070] Formula (9) can be used to judge the normal phase sequence and the three-phase completely wrong phase sequence.

[0071] Since the above derivation is simplified, the higher the speed, the more accurate the three-phase full fault state judgment formula is. Combining formula (13) and actual engineering experience, it is preferred that the detection speed threshold N th It can be set to 20%-100% of the rated speed of the motor. It can quickly and accurately determine the three-phase phase sequence error. In actual application, it can be selected based on speed and accuracy.

[0072] S32. Based on the q-axis voltage, q-axis current, motor speed, and resistance parameters of the permanent magnet synchronous motor, determine whether the phase sequence connection between the motor and the driver is in a three-phase full-fault state using the three-phase full-fault phase sequence formula. The three-phase full-fault phase sequence formula is expressed as:

[0073] (u q * -Ri q * )(N r )<-1(14)

[0074] Among them, u q * represents the q-axis voltage, i q * represents the q-axis current, Nr is the motor speed, and R is the resistance parameter.

[0075] Specifically, the q-axis voltage is set in real time by the motor drive controller program, and the q-axis voltage output by the driver is controlled. The q-axis current (unit: A) is collected in real time by the current sensor.

[0076] When formula (14) is satisfied, the phase sequence connection between the motor and the driver is determined to be in a three-phase full-fault state, and the motor speed N that satisfies the condition is recorded.r 1.

[0077] Step 4: Monitor the duration of the three-phase full fault state. When the duration of the three-phase full fault state exceeds the preset detection time threshold, record the motor speed N. r 2; when | N r 2|>|N r 1|, triggering a three-phase phase sequence error alarm.

[0078] Monitor the duration T of the three-phase full fault state and preset the detection time threshold as T th (For example, 1 millisecond to 100 milliseconds). When the following conditions are met, the alarm signal is triggered, and the conditions include:

[0079] (1)T>T th ;

[0080] (2) When T>T th When the motor speed Nr2 is recorded, and |Nr2|>|Nr1| is satisfied, it indicates that the motor continues to accelerate or reverse due to the wrong phase sequence, triggering the three-phase wrong phase sequence alarm.

[0081] Specifically, a three-phase fault sequence alarm triggers: driver shutdown protection, communication to a higher-level computer, automatic motor power cutoff, or fault notification via the human-machine interface. Dual verification of time thresholds and speed changes reduces false positives, ensuring equipment and personnel safety.

[0082] The real-time detection method for the three-phase full-fault phase sequence of a permanent magnet synchronous motor provided in this embodiment determines the three-phase full-fault phase sequence by a formula that characterizes the motor speed, q-axis voltage, and q-axis current parameters, and combines it with speed change comparison logic. This solves the problem of insufficient real-time phase mismatch detection in the existing technology and the need to take rapid protective measures for high-risk three-phase full-fault states during motor operation, thereby avoiding serious safety accidents.

[0083] In summary, this embodiment provides a method that can accurately identify the three-phase fully wrong phase sequence in real time. This method can effectively identify the three-phase fully wrong phase sequence by real-time acquisition of motor operation data and combined with the three-phase fully wrong phase sequence formula, and promptly trigger the protection mechanism at the early stage of the fault. Compared with the traditional phase sequence detection method, this method has higher accuracy and faster response speed, and can accurately identify the three-phase fully wrong phase sequence in real time without stopping the machine or connecting external sensors. It can directly use the built-in current and voltage signals of the driver to achieve real-time detection. It adapts to complex working conditions through dual verification of time threshold and speed change. It is suitable for online fault diagnosis and protection of permanent magnet synchronous motor drive systems, and is suitable for fields with high reliability and real-time requirements such as electric vehicle drives and industrial servo systems.

[0084] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for real-time detection of three-phase full-wrong phase sequence of permanent magnet synchronous motor, characterized in that: The following steps are involved: Get the resistance parameters of the permanent magnet synchronous motor; When the permanent magnet synchronous motor enters the enabled state, the motor speed is collected in real time through the encoder, and the detection speed threshold is set. When the motor speed is greater than the preset detection speed threshold, it is determined that the permanent magnet synchronous motor meets the three-phase full phase sequence detection condition; When it is determined that the permanent magnet synchronous motor meets the three-phase full phase sequence detection conditions, judge whether the phase sequence connection between the motor and the driver is in a three-phase full phase sequence state based on the q-axis voltage, q-axis current, motor speed and resistance parameters of the permanent magnet synchronous motor; when it is determined that the phase sequence connection between the motor and the driver is in a three-phase full phase sequence state, record the motor speed N at this time. r 1; Monitor the duration of the three-phase full fault state. When the duration of the three-phase full fault state exceeds the preset detection time threshold, the motor speed N is recorded. r 2; when | N r 2|>|N r 1|, triggering a three-phase phase sequence error alarm.

2. A method for real-time detection of three-phase full-wrong phase sequence of a permanent magnet synchronous motor according to claim 1, characterized in that: The determining, based on the q-axis voltage, q-axis current, motor speed, and resistance parameters of the permanent magnet synchronous motor, whether the phase sequence connection between the motor and the driver is in a three-phase full fault state includes: According to the phase sequence of the three-phase full fault between the motor and the driver, the three-phase full fault phase sequence formula is calculated based on the motor stator voltage equation; Based on the q-axis voltage, q-axis current, motor speed, and resistance parameters of the permanent magnet synchronous motor, the three-phase full-fault phase sequence formula is used to determine whether the phase sequence connection between the motor and the driver is in a three-phase full-fault state. The three-phase full-fault phase sequence formula is expressed as: (u q * -Ri q * )(N r )<-1 Among them, u q * represents the q-axis voltage, i q * represents the q-axis current, Nr is the motor speed, and R is the resistance parameter.

3. A method for real-time detection of three-phase full-wrong phase sequence of a permanent magnet synchronous motor according to claim 2, characterized in that: The q-axis voltage is set in real time by a program instruction of a motor drive controller, and the q-axis current is collected in real time by a current sensor.

4. A method for real-time detection of three-phase full-wrong phase sequence of a permanent magnet synchronous motor according to claim 1, characterized in that: The detection speed threshold value has a value range of 20%-100% of the rated speed of the motor.

5. The method for real-time detection of three-phase full-wrong phase sequence of a permanent magnet synchronous motor according to claim 1 is characterized in that: The detection time threshold value ranges from 1 millisecond to 100 milliseconds.

6. A method for real-time detection of three-phase full-wrong phase sequence of a permanent magnet synchronous motor according to claim 1, characterized in that: The triggering of the three-phase full phase sequence error alarm includes: triggering the driver to shut down for protection or communicating an alarm to a host computer, automatically cutting off the power supply to the motor or prompting a fault message through a human-machine interface.

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