A brushless motor controller fault diagnosis method and device

Abstract

The present invention relates to a brushless motor controller fault diagnosis method, comprising the following steps: Step S1, diagnosing whether inverter circuits Q1, Q2, Q3, Q4, Q5, and Q6 are short-circuited; Step S2, diagnosing whether inverter circuit Q1 is controllable; Step S3, diagnosing whether inverter circuit Q3 is controllable; Step S4, diagnosing whether inverter circuit Q5 is controllable; Step S5, diagnosing whether inverter circuit Q2 is controllable and whether motor phase lines U and V are open-circuited; Step S6, diagnosing whether inverter circuit Q4 is controllable and whether motor phase lines V and W are open-circuited; Step S7, diagnosing whether inverter circuit Q6 is controllable and whether motor phase lines U and W are open-circuited. The present invention also provides a diagnostic device for implementing the diagnostic method. The diagnostic method proposed in the present invention completes the diagnosis before the motor is started. Regarding detecting whether the MOSFET is short-circuited, the present invention does not cause impact on the MOSFET, reduces motor vibration, and improves system reliability and diagnostic stability.

Description

Technical Field

[0001] The present invention relates to the field of automobile brushless motor controllers, in particular to a brushless motor controller fault diagnosis method and device. Background Art

[0002] Brushless Direct Current Motor (BLDCM), also known as BLDC motor, is an improved motor that combines the advantages of DC and AC motors. Its rotor uses permanent magnet excitation, resulting in a small size, light weight, simple structure, and easy maintenance. BLDC motors also offer advantages such as easy control and high efficiency and energy saving. They are widely used in new energy vehicle water pumps, electronic fan water pumps, and electronic oil pumps.

[0003] Currently, controllers generally diagnose whether the MOSFET is short-circuited while the motor is running. The general diagnostic method uses a comparator to detect the conduction voltage drop of the MOSFET, which requires a large current to flow through the MOSFET. This method will damage the MOSFET; if the MOSFET is already short-circuited, the short-circuit risk may be increased.

[0004] To diagnose whether the MOS is open during motor operation, the general detection method needs to determine whether the three-phase current is balanced. When the current is small, it is easy to misdetect or not detect when the current is small. In addition, the motor speed will be unstable during operation, causing vibration and damage to other components.

[0005] Reference patent: CN202410515726.2 <Vehicle-based motor phase loss detection method, vehicle and related equipment>, specifically diagnoses whether the motor is phase-lost based on the detected current imbalance when the motor is running; Reference patent: CN118432486A <Motor controller, phase loss fault detection method and powertrain> also performs detection when the motor is running.

[0006] Both patents have the following problems: both are tested when the motor is running, and each test will impact the MOS tube, causing a MOS short circuit; at the same time, they diagnose whether the motor is open-circuited. If the motor is open-circuited, it will cause unbalanced torque of the motor and cause vibration, which is easy to cause false detection when running at a lower current. Summary of the Invention

[0007] In response to the above problems, the present invention provides a brushless motor controller fault diagnosis method and device that completes diagnosis before the motor is started, thereby improving system reliability and diagnostic stability.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: a brushless motor controller fault diagnosis method, which specifically includes the following steps:

[0009] The sampling circuit detects the voltages at points A, B, and C as Va, Vb, and Vc, and also detects the power supply voltage as Vdh.

[0010] Step S1, diagnose whether the inverter circuits Q1, Q2, Q3, Q4, Q5, and Q6 are short-circuited;

[0011] Turn off Q1, Q2, Q3, Q4, Q5, and Q6, and detect Va, Vb, Vc, and Vhd;

[0012] If Va is in the range [(0+Voffset), (Vdh-Voffset)], Q1 is not short-circuited to Vdh, and Q2 is not short-circuited to SL;

[0013] If Vb is in the range [(0+Voffset), (Vdh-Voffset)], Q3 is not short-circuited to Vdh, and Q4 is not short-circuited to SL.

[0014] If Vb is in the range [(0+Voffset), (Vdh-Voffset)], Q5 is not short-circuited to Vdh, and Q6 is not short-circuited to SL.

[0015] Voffset is the voltage offset and is set to 1.5V;

[0016] Step S2, diagnosing whether the inverter circuit Q1 is controllable;

[0017] Step S3, diagnosing whether the inverter circuit Q3 is controllable;

[0018] Step S4, diagnose whether the inverter circuit Q5 is controllable;

[0019] Step S5, diagnose whether the inverter circuit Q2 is controllable and whether the motor phase lines U and V are open;

[0020] Step S6, diagnose whether the inverter circuit Q4 is controllable and whether the motor phase lines V and W are open;

[0021] Step S7: diagnose whether the inverter circuit Q6 is controllable and whether the motor phase lines U and W are open.

[0022] Preferably, the specific operation of step S2 is as follows:

[0023] The control circuit turns on Q1, turns off Q2, Q3, Q4, Q5, and Q6, and detects Va, Vb, Vc, and Vhd;

[0024] If the voltage at point A is Va>Vdh-Voffset, Q1 can be controlled so that point A is connected to Vhd.

[0025] Preferably, the specific operation of step S3 is as follows:

[0026] The control circuit turns on Q3 and turns off Q1, Q2, Q4, Q5, Q6, and detects Va, Vb, Vc, Vhd;

[0027] If the voltage at point A, Vb > Vdh - Voffset, then Q3 can be controlled to connect point B to Vhd.

[0028] Preferably, the specific operation of step S4 is as follows,

[0029] The control circuit turns on Q5 and turns off Q1, Q2, Q3, Q4, Q6, and detects Va, Vb, Vc, Vhd;

[0030] If the voltage at point A, Vac > Vdh - Voffset, then Q5 can be controlled to connect point C to Vhd.

[0031] Preferably, the specific operation of step S5 is as follows,

[0032] The control circuit turns on Q2 and turns off Q1, Q3, Q4, Q5, Q6, and detects Va, Vb, Vc, Vhd;

[0033] If the voltage at point A, Va < GND + Voffset, then Q2 can be controlled to connect point A to SL;

[0034] If the voltage at point B, Vb < GND + Voffset, then the motor phase lines U, V are connected to point A, that is, the motor phase lines U and V are not open;

[0035] If the voltage at point B, Vb is in the range of [(Vibsh + Voffset), (Vibsh - Voffset)], then at least one of the motor phase lines U, V and point A is open.

[0036] Preferably, the specific operation of step S6 is as follows,

[0037] The control circuit turns on Q4 and turns off Q1, Q, Q3, Q5, Q6; detects Va, Vb, Vc, Vhd;

[0038] If the voltage at point B, Vb < GND + Voffset, then Q4 can be controlled to connect point B to SL;

[0039] If the voltage at point C, Vc < GND + Voffset, then the motor phase lines V, W are connected to point B, that is, the motor phase lines V and W are not open;

[0040] If the voltage at point C, Vc is in the range of [(Vibsh + Voffset), (Vibsh - Voffset)], then at least one of the motor phase lines V, W and point B is open.

[0041] Preferably, the specific operation of step S7 is as follows,

[0042] The control circuit turns on Q6 and turns off Q1, Q2, Q3, Q4, and Q5; Va, Vb, Vc, and Vhd are detected.

[0043] If the voltage Vc at point A < GND + Voffset, then Q6 can be controlled so that point C is connected to SL.

[0044] If the voltage Va at point B < GND + Voffset, then the motor phase lines U, W, and point C are connected, that is, the motor phase lines U and W are not open.

[0045] If the voltage Va at point B is in the range of [(Vibsh + Voffset), (Vibsh - Voffset)], then at least one of the motor phase lines U, W, and point C is open.

[0046] The present invention also provides a brushless motor controller fault diagnosis device, which is characterized in that it is used to implement the above brushless motor controller fault diagnosis method, including:

[0047] A power supply circuit, a control circuit, a pre-drive circuit, an inverter circuit, and a detection circuit. The power supply circuit is used to supply power to the entire device. The control circuit is used to control the operation of the motor and sample and diagnose the signals of the detection circuit. The inverter circuit is used to drive the mosfet switches and provide a constant current Ibsh, and the inverter circuit is electrically connected to the motor. The detection circuit is used to detect and drive the output voltage, and at the same time, the output end of the detection circuit is connected to the ADC sampling circuit of the control circuit.

[0048] Preferably, the motor includes motor three-phase lines U, V, and W. The inverter circuit includes three detection points, namely point A, point B, and point C. The inverter circuit also includes triodes Q1, Q2, Q3, Q4, Q5, and Q6. Q1, Q2, and Q3 are connected in parallel and connected to Vhd. Q4, Q5, and Q6 are connected in parallel and connected to GND. At the same time, Q1 and Q2, Q3 and Q4, and Q5 and Q6 are all connected in series. And point A is located between Q1 and Q2, point B is located between Q3 and Q4, and point C is located between Q5 and Q6. The motor phase lines U, V, and W are respectively connected to point A, point B, and point C.

[0049] Preferably, the detection circuit includes resistors R1, R2, and capacitor C. Resistors R1 and R2 are connected in parallel to form a voltage division circuit, and the resistors R1, R2, and capacitor C are connected in series to form a filtering circuit.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] 1. The diagnostic method proposed by the present invention completes the diagnosis before the motor is started, and does not need to be started when the motor is running. For detecting whether the MOS is short-circuited, the present invention will not cause impact on the MOS tube and will not cause the damage of the MOS short circuit to expand;

[0052] 2. The present invention can diagnose whether the motor is open-circuited, thereby avoiding vibration caused by torque imbalance due to phase loss in the motor.

[0053] 3. The present invention can avoid the problem of false detection when the motor is running at low current;

[0054] 4. The present invention improves the reliability and diagnostic stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a schematic structural diagram of the diagnostic device of the present invention;

[0056] Figure 2 It is a schematic diagram of the control circuit in the present invention;

[0057] Figure 3 This is a schematic diagram of the inverter side in the present invention;

[0058] Figure 4 It is a schematic diagram of the detection circuit principle in the present invention;

[0059] Figure 5 This is a schematic diagram of the detection circuit connection in the present invention;

[0060] Figure 6 It is a schematic flow chart of the diagnostic method of the present invention. DETAILED DESCRIPTION

[0061] The following will be combined Figure 1-6 The present invention will be described in detail. The exemplary embodiments and descriptions of the present invention are provided herein to explain the present invention but not to limit the present invention.

[0062] A method for diagnosing a fault in a brushless motor controller comprises the following steps:

[0063] The sampling circuit detects the voltages at points A, B, and C as Va, Vb, and Vc, and also detects the power supply voltage as Vdh.

[0064] like Figure 4 As shown in the detection principle diagram, the pre-driver Ibsh generates a current of 40uA, and the voltage generated by the overcurrent resistor Rsh1 is Vibsh = Ibsh*Rsh1 = 40uA*80KΩ = 3.2V.

[0065] If Q1 and the power supply Vdh are short-circuited, the Va voltage is equal to Vdh; if Q2 and SL are short-circuited, since SL is connected to GND, Va = 0V.

[0066] Step S1, diagnose whether the inverter circuits Q1, Q2, Q3, Q4, Q5, and Q6 are short-circuited;

[0067] Turn off Q1, Q2, Q3, Q4, Q5, and Q6, and detect Va, Vb, Vc, and Vhd;

[0068] If Va is in the range [(0+Voffset), (Vdh-Voffset)], Q1 is not short-circuited to Vdh, and Q2 is not short-circuited to SL;

[0069] If Vb is in the range [(0+Voffset), (Vdh-Voffset)], Q3 is not short-circuited to Vdh, and Q4 is not short-circuited to SL.

[0070] If Vb is in the range [(0+Voffset), (Vdh-Voffset)], Q5 is not short-circuited to Vdh, and Q6 is not short-circuited to SL.

[0071] Voffset is the voltage offset, which is set to 1.5V to prevent false detection;

[0072] After step S1, diagnose whether Q1, Q2, Q3, Q4, Q5, and Q6 are short-circuited;

[0073] Step S2, diagnosing whether the inverter circuit Q1 is controllable;

[0074] The control circuit turns on Q1, turns off Q2, Q3, Q4, Q5, and Q6, and detects Va, Vb, Vc, and Vhd;

[0075] If the voltage at point A is Va>Vdh-Voffset, Q1 can be controlled so that point A is connected to Vhd.

[0076] Step S3, diagnosing whether the inverter circuit Q3 is controllable;

[0077] The control circuit turns on Q3, turns off Q1, Q2, Q4, Q5, and Q6, and detects Va, Vb, Vc, and Vhd;

[0078] If the voltage Vb at point A is greater than Vdh-Voffset, Q3 can be controlled so that point B is connected to Vhd.

[0079] Step S4, diagnose whether the inverter circuit Q5 is controllable;

[0080] The control circuit turns on Q5, turns off Q1, Q2, Q3, Q4, and Q6, and detects Va, Vb, Vc, and Vhd;

[0081] If the voltage at point A, Vac, is greater than Vdh-Voffset, Q5 can be controlled so that point C is connected to Vhd;

[0082] After steps S2, S3, and S4, it can be diagnosed whether Q1, Q3, and Q5 are controllable;

[0083] Step S5, diagnose whether the inverter circuit Q2 is controllable and whether the motor phase lines U and V are open;

[0084] The control circuit turns on Q2, turns off Q1, Q3, Q4, Q5, and Q6, and detects Va, Vb, Vc, and Vhd;

[0085] If the voltage Va at point A < GND + Voffset, then Q2 is controllable, and point A is connected to SL;

[0086] If the voltage Vb at point B < GND + Voffset, then the motor phase lines U and V are connected to point A, that is, the motor phase lines U and V are not open;

[0087] If the voltage Vb at point B is in the range of [(Vibsh + Voffset), (Vibsh - Voffset)], then at least one of the motor phase lines U, V, and point A is open;

[0088] Step S6, diagnose whether the inverter circuit Q4 is controllable and whether the motor phase lines V and W are open;

[0089] The control circuit turns on Q4, turns off Q1, Q2, Q3, Q5, and Q6; detects Va, Vb, Vc, and Vhd;

[0090] If the voltage Vb at point B < GND + Voffset, then Q4 is controllable, and point B is connected to SL;

[0091] If the voltage Vc at point C < GND + Voffset, then the motor phase lines V and W are connected to point B, that is, the motor phase lines V and W are not open;

[0092] If the voltage Vc at point C is in the range of [(Vibsh + Voffset), (Vibsh - Voffset)], then at least one of the motor phase lines V, W, and point B is open;

[0093] Step S7, diagnose whether the inverter circuit Q6 is controllable and whether the motor phase lines U and W are open;

[0094] The control circuit turns on Q6, turns off Q1, Q2, Q3, Q4, and Q5; detects Va, Vb, Vc, and Vhd;

[0095] If the voltage Vc at point A < GND + Voffset, then Q6 is controllable, and point C is connected to SL;

[0096] If the voltage Va at point B < GND + Voffset, then the motor phase lines U and W are connected to point C, that is, the motor phase lines U and W are not open;

[0097] If the voltage Va at point B is in the range [(Vibsh+Voffset), (Vibsh-Voffset)], at least one of the motor phase lines U, W and point C is open.

[0098] Through steps S5, S6, and S7, it can be diagnosed whether Q2, Q4, and Q6 are open-circuited; and whether the motor phase lines U, V, and W are open-circuited.

[0099] The present invention also provides a brushless motor controller fault diagnosis device for implementing the above-mentioned brushless motor controller fault diagnosis method, comprising:

[0100] A power supply circuit, a control circuit, a pre-drive circuit, an inverter circuit and a detection circuit. The power supply circuit is used to supply power to the entire device. The control circuit is used to control the operation of the motor and sample the detection circuit signal for diagnosis. The inverter circuit is used to drive the MOSFET switch and provide a constant current Ibsh. The inverter circuit is electrically connected to the motor. The constant current source Ibsh can provide a current of 40uA. The detection circuit is used to detect and drive the output voltage. At the same time, the output end of the detection circuit is connected to the ADC sampling circuit of the control circuit.

[0101] Specifically, the motor includes three-phase lines U, V, and W of the motor, the inverter circuit includes three detection points at points A, B, and C, and the inverter circuit also includes transistors Q1, Q2, Q3, Q4, Q5, and Q6. The Q1, Q2, and Q3 are connected in parallel and connected to Vhd, and the Q4, Q5, and Q6 are connected in parallel and connected to GND. At the same time, Q1 and Q2, Q3 and Q4, Q5 and Q6 are all arranged in series, and point A is set between Q1 and Q2, point B is set between Q3 and Q4, and point C is set between Q5 and Q6. The motor phase lines U, V, and W are connected to points A, B, and C, respectively.

[0102] Specifically, the detection circuit includes resistors R1, R2 and a capacitor C. The resistors R1 and R2 are connected in parallel to form a voltage divider circuit, and the resistors R1, R2 and the capacitor C are connected in series to form a filter circuit. Figure 5 shown.

[0103] By combining the device and the diagnostic method, the present invention can complete the diagnosis before the motor is started, and there is no need to start the diagnosis when the motor is running. For detecting whether the MOS is short-circuited, the present invention will not cause impact on the MOS tube and will not cause the harm of the MOS short circuit to expand; at the same time, the present invention can diagnose whether the motor is open-circuited, which can avoid the vibration caused by the torque imbalance caused by the motor's phase loss operation, and can also avoid the problem of false detection when the motor is running at a low current; thereby improving the reliability of the system and the diagnostic stability.

[0104] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A brushless motor controller fault diagnosis method, characterized in that: The specific steps include: The sampling circuit detects the voltages at points A, B, and C as Va, Vb, and Vc, and also detects the power supply voltage as Vdh. Step S1, diagnose whether the inverter circuits Q1, Q2, Q3, Q4, Q5, and Q6 are short-circuited; Turn off Q1, Q2, Q3, Q4, Q5, and Q6, and detect Va, Vb, Vc, and Vhd; If Va is in the range [(0+Voffset), (Vdh-Voffset)], Q1 is not short-circuited to Vdh, and Q2 is not short-circuited to SL; If Vb is in the range [(0+Voffset), (Vdh-Voffset)], Q3 is not short-circuited to Vdh, and Q4 is not short-circuited to SL; If Vb is in the range [(0+Voffset), (Vdh-Voffset)], Q5 is not short-circuited to Vdh, and Q6 is not short-circuited to SL; Voffset is the voltage offset and is set to 1.5V; Step S2, diagnosing whether the inverter circuit Q1 is controllable; Step S3, diagnosing whether the inverter circuit Q3 is controllable; Step S4, diagnose whether the inverter circuit Q5 is controllable; Step S5, diagnose whether the inverter circuit Q2 is controllable and whether the motor phase lines U and V are open; Step S6, diagnose whether the inverter circuit Q4 is controllable and whether the motor phase lines V and W are open; Step S7, diagnose whether the inverter circuit Q6 is controllable and whether the motor phase lines U and W are open; Through steps S1 to S7, it is diagnosed that the inverter circuits Q1, Q2, Q3, Q4, Q5, and Q6 are not short-circuited and are controllable, and the motor phase lines U, V, and W are not open-circuited, so the brushless motor controller is fault-free.

2. The brushless motor controller fault diagnosis method according to claim 1, characterized in that: The specific operation of step S2 is as follows: The control circuit turns on Q1, turns off Q2, Q3, Q4, Q5, and Q6, and detects Va, Vb, Vc, and Vhd; If the voltage at point A, Va > Vdh-Voffset, then Q1 can be controlled so that point A is connected to Vhd.

3. The brushless motor controller fault diagnosis method according to claim 1, characterized in that: The specific operation of step S3 is as follows: The control circuit turns on Q3, turns off Q1, Q2, Q4, Q5, and Q6, and detects Va, Vb, Vc, and Vhd; If the voltage Vb at point A > Vdh-Voffset, Q3 can be controlled so that point B is connected to Vhd.

4. The brushless motor controller fault diagnosis method according to claim 1, wherein: The specific operation of step S4 is as follows: The control circuit turns on Q5, turns off Q1, Q2, Q3, Q4, and Q6, and detects Va, Vb, Vc, and Vhd; If the voltage at point A, Vac > Vdh-Voffset, then Q5 can be controlled so that point C is connected to Vhd.

5. The brushless motor controller fault diagnosis method according to claim 1, characterized in that: The specific operation of step S5 is as follows: The control circuit turns on Q2, turns off Q1, Q3, Q4, Q5, and Q6, and detects Va, Vb, Vc, and Vhd; If the voltage at point A, Va < GND + Voffset, then Q2 can be controlled so that point A is connected to SL; If the voltage Vb at point B is less than GND+Voffset, the motor phase lines U and V are connected to point A, that is, the motor phase lines U and V are not open; If the voltage Vb at point B is in the range [(Vibsh+Voffset), (Vibsh-Voffset)], then at least one of the motor phase lines U, V and point A is open circuit.

6. The brushless motor controller fault diagnosis method according to claim 1, characterized in that: The specific operation of step S6 is as follows: The control circuit turns on Q4 and turns off Q1, Q2, Q3, Q5, and Q6; detects Va, Vb, Vc, and Vhd; If the voltage at point B, Vb < GND + Voffset, then Q4 can be controlled so that point B is connected to SL; If the voltage Vc at point C is less than GND+Voffset, the motor phase lines V and W are connected to point B, that is, the motor phase lines V and W are not open; If the voltage Vc at point C is in the range [(Vibsh+Voffset), (Vibsh-Voffset)], then at least one of the motor phase lines V, W and point B is open circuit.

7. The brushless motor controller fault diagnosis method according to claim 1, characterized in that: The specific operation of step S7 is as follows: The control circuit turns on Q6 and turns off Q1, Q2, Q3, Q4, and Q5; detects Va, Vb, Vc, and Vhd; If the voltage at point A, Vc < GND + Voffset, then Q6 can be controlled so that point C is connected to SL; If the voltage Va at point B is less than GND+Voffset, the motor phase lines U and W are connected to point C, that is, the motor phase lines U and W are not open; If the voltage Va at point B is in the range [(Vibsh+Voffset), (Vibsh-Voffset)], then at least one of the motor phase lines U, W and point C is open circuit.

8. A brushless motor controller fault diagnosis device, characterized in that: A method for diagnosing a brushless motor controller fault according to any one of claims 1 to 7, comprising: A power supply circuit, a control circuit, a pre-drive circuit, an inverter circuit and a detection circuit. The power supply circuit is used to supply power to the entire device. The control circuit is used to control the operation of the motor and sample the detection circuit signal for diagnosis. The inverter circuit is used to drive the MOSFET switch and provide a constant current Ibsh. The inverter circuit is electrically connected to the motor. The detection circuit is used to detect and drive the output voltage. At the same time, the output end of the detection circuit is connected to the ADC sampling circuit of the control circuit.

9. The brushless motor controller fault diagnosis device according to claim 8, characterized in that: The motor includes three-phase lines U, V, and W of the motor, the inverter circuit includes three detection points at points A, B, and C, and the inverter circuit also includes transistors Q1, Q2, Q3, Q4, Q5, and Q6. The Q1, Q2, and Q3 are connected in parallel and connected to Vhd, and the Q4, Q5, and Q6 are connected in parallel and connected to GND. At the same time, Q1 and Q2, Q3 and Q4, and Q5 and Q6 are all arranged in series, and point A is set between Q1 and Q2, point B is set between Q3 and Q4, and point C is set between Q5 and Q6. The motor phase lines U, V, and W are connected to points A, B, and C, respectively.

10. The brushless motor controller fault diagnosis device according to claim 8, characterized in that: The detection circuit includes resistors R1, R2 and a capacitor C. The resistors R1 and R2 are connected in parallel to form a voltage divider circuit, and the resistors R1, R2 and the capacitor C are connected in series to form a filter circuit.

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