Direct current brushless motor drive circuit

Abstract

A direct-current brushless motor driving circuit includes a power stage circuit for driving a direct-current brushless motor according to a pulse width modulation signal, and an abnormality diagnosis circuit for judging a rotation abnormality state of the direct-current brushless motor according to a second parameter under a condition that a first parameter is controlled, wherein the first parameter and the second parameter are related to rotation of the direct-current brushless motor.

Description

TECHNICAL FIELD

[0001] The present invention relates to a direct current brushless motor driving circuit, and in particular, to a direct current brushless motor driving circuit capable of detecting abnormal rotation of a direct current brushless motor. BACKGROUND

[0002] Due to the high efficiency of direct current brushless motor, the application of direct current brushless motor has become more and more popular. Figure 1 Fig. 1 is a block diagram showing a known direct current brushless motor driving circuit. Figure 1 The known direct current brushless motor driving circuit 101 is used to receive signals from an external host 103 and drive a direct current brushless motor 102 accordingly. The conventional direct current brushless motor driving circuit 101 only provides protection mechanisms to protect power stage circuits from overcurrent, overvoltage, undervoltage, temperature overheat, etc. However, mechanical components of the motor can be aged or failed due to long-term operation, such as bearing failure, fan blade breakage, etc. Such conditions cannot be detected by the prior art.

[0003] In view of the above, the present invention proposes an innovative direct current brushless motor driving circuit to overcome the deficiencies of the prior art. SUMMARY

[0004] In one aspect, the present invention provides a direct current brushless motor driving circuit comprising: a power stage circuit for driving a direct current brushless motor according to a pulse width modulation (PWM) signal; and an abnormality diagnosis circuit for judging an abnormal rotation state of the direct current brushless motor according to a second parameter under a condition that a first parameter is controlled; wherein the first parameter and the second parameter are related to rotation of the direct current brushless motor.

[0005] In one embodiment, the first parameter comprises at least one of the following motor parameters, and the second parameter comprises at least another one of the motor parameters: (1) a rotation speed of the direct current brushless motor; (2) a motor temperature; (3) an ambient temperature; (4) an input current of the direct current brushless motor; (5) an input voltage of the direct current brushless motor; (6) a duty cycle of the PWM signal; wherein the first parameter and the second parameter are different.

[0006] In one embodiment, when the first parameter is controlled at a preset fixed value, the abnormality diagnosis circuit judges the abnormal rotation state of the direct current brushless motor according to whether the second parameter exceeds a parameter preset range.

[0007] In one embodiment, the motor parameter is detected or estimated by a corresponding parameter detection element.

[0008] In one embodiment, the parameter detection element includes at least one of the following: (1) a speed detection element for detecting the speed of the brushless DC motor; (2) a motor temperature detection element for detecting the motor temperature; (3) an ambient temperature detection element for detecting the ambient temperature; (4) a current detection element for detecting the input current; (5) a voltage detection element for detecting the input voltage; and (6) a speed estimation element for estimating the speed of the brushless DC motor.

[0009] In one embodiment, the preset range of the parameter corresponding to the second parameter is related to at least one of the plurality of motor parameters.

[0010] In one embodiment, when the first parameter is the rotational speed of the brushless DC motor, the brushless DC motor drive circuit further includes a rotational speed detection element and a rotational speed control element. The rotational speed detection element is used to detect the rotational speed of the brushless DC motor, and the rotational speed control element is used to control the rotational speed of the brushless DC motor to the fixed value based on a rotational speed reference value and the rotational speed of the brushless DC motor fed back by the rotational speed detection element.

[0011] In one embodiment, the preset range of the parameter is stored in the power stage circuit or the fault diagnosis circuit, or is set by multiple external pins or by an external host.

[0012] In one embodiment, the brushless DC motor drive circuit is coupled to the external host via an interface that includes a communication bus or multiple dedicated pins.

[0013] In one embodiment, the DC brushless motor drive circuit further includes a commutation and PWM control circuit for generating the PWM signal based on a rotor angle and the duty cycle.

[0014] In one embodiment, the brushless DC motor drive circuit further includes a speed control element for generating the duty cycle based on the difference between a speed reference value and the speed of the brushless DC motor.

[0015] In one embodiment, the first parameter is the duty cycle of the PWM signal, and the second parameter is the rotational speed of the brushless DC motor.

[0016] In one embodiment, the first parameter is the duty cycle of the PWM signal, and the second parameter is the motor temperature and / or the ambient temperature.

[0017] In one embodiment, the first parameter is the input current of the brushless DC motor, and the second parameter is the rotational speed of the brushless DC motor.

[0018] In one embodiment, the first parameter is the input current, and the second parameter is the motor temperature and / or the ambient temperature.

[0019] One advantage of this invention is that it can diagnose mechanical faults of a motor by monitoring the duty cycle, motor speed, motor input current, motor input voltage, motor temperature, or ambient temperature.

[0020] Another advantage of this invention is that it can report warnings or errors about the motor status to an external host.

[0021] The following detailed description through specific embodiments will make it easier to understand the purpose, technical content, features, and effects achieved by the present invention. Attached Figure Description

[0022] Figure 1 This is a block diagram showing a known DC brushless motor drive circuit.

[0023] Figure 2A This is a circuit diagram showing a DC brushless motor drive circuit according to an embodiment of the present invention.

[0024] Figure 2B This is a schematic diagram showing the characteristic curves of a DC brushless motor drive circuit according to an embodiment of the present invention.

[0025] Figure 3 This is a circuit diagram showing a DC brushless motor drive circuit according to another embodiment of the present invention.

[0026] Figure 4 This is a circuit diagram showing a DC brushless motor drive circuit according to another embodiment of the present invention.

[0027] Figure 5 This is a circuit diagram showing a DC brushless motor drive circuit according to another embodiment of the present invention.

[0028] Explanation of symbols in the diagram

[0029] 101, 201, 201', 201", 201"': DC brushless motor drive circuit

[0030] 102, 202: DC brushless motor

[0031] 103, 203: External Host

[0032] 2011: Power Stage Circuits

[0033] 2012: Anomaly Diagnosis Circuit

[0034] 2013, 2013': Parameter detection element

[0035] 2013a: Rotational speed detection element

[0036] 2013b: Motor temperature detection element

[0037] 2013c: Ambient temperature detection element

[0038] 2013d: Current Detection Element

[0039] 2013e: Voltage Detection Element

[0040] 2013f: Speed ​​Estimation Element

[0041] 2014: Commutation and PWM Control Circuits

[0042] 2015: Interface Circuit

[0043] 20121: Anomaly Diagnosis Controller

[0044] 20122: Analog-to-Digital Converter (ADC)

[0045] 20123: Multitasking Module (MUX)

[0046] D: Duty Cycle

[0047] Dm: Minimum duty cycle

[0048] DM: Maximum duty cycle

[0049] dUH, dUL, dVH, dVL, dWH, dWL: Pulse Width Modulation (PWM) signals; eu, ev, ew: Back Electromotive Force

[0050] Iin: Input current

[0051] Iinm: Minimum input current

[0052] IinM: Maximum input current

[0053] Inp: Input pulse width modulation (PWM) signal

[0054] Iu, Iv, Iw: Operating current

[0055] Lu, Lv, Lw: Phase inductance

[0056] N: Neutral point

[0057] P1: First parameter

[0058] P2: Second parameter

[0059] θ, θe: Rotor angle

[0060] Qh1, Qh2, Qh3: Upper bridge power components

[0061] Ql1, Ql2, Ql3: Lower bridge power components

[0062] Rcs: Resistance

[0063] Ru, Rv, Rw: Phase resistance

[0064] Te: Ambient temperature

[0065] Tem: Minimum ambient temperature

[0066] TeM: Maximum ambient temperature

[0067] Tm: Motor temperature

[0068] Tmm: Minimum motor temperature

[0069] TmM: Maximum motor temperature

[0070] Vin: Input voltage

[0071] Vinm: Minimum input voltage

[0072] VinM: Maximum input voltage

[0073] ω, ωe: rotational speed

[0074] ωm: Minimum rotational speed

[0075] ωM: Maximum rotational speed

[0076] ωref: Reference value for rotational speed

[0077] Wn: Abnormal warning message Detailed Implementation

[0078] The accompanying drawings in this invention are all schematic and are mainly intended to show the coupling relationship between various circuits and the relationship between various signal waveforms. The circuits, signal waveforms and frequencies are not drawn to scale.

[0079] Figure 2A This is a circuit diagram showing a DC brushless motor drive circuit 201 according to an embodiment of the present invention. Figure 2A As shown, the DC brushless motor drive circuit 201 includes a power stage circuit 2011, an abnormality diagnosis circuit 2012, a speed detection element 2013a, a commutation and pulse width modulation (PWM) control circuit 2014, and an interface circuit 2015.

[0080] Power stage circuit 2011 drives DC brushless motor 202 according to pulse width modulation (PWM) signals dUH, dUL, dVH, dVL, dWH, and dWL. Power stage circuit 2011 is coupled to commutation and PWM control circuit 2014. An anomaly diagnosis circuit 2012 is used to determine an abnormal rotation state of DC brushless motor 202 based on a second parameter P2 when a first parameter P1 is controlled, and is coupled to interface circuit 2015. When the anomaly diagnosis circuit 2012 determines that DC brushless motor 202 has an abnormal rotation, it generates an anomaly warning message Wn to interface circuit 2015. In one embodiment, the first parameter P1 and the second parameter P2 are related to the rotation of DC brushless motor 202. In one embodiment, when the first parameter P1 is controlled at a preset fixed value, the anomaly diagnosis circuit 2012 determines the abnormal rotation state of DC brushless motor 202 based on whether the second parameter P2 exceeds a preset parameter range. In one embodiment, the aforementioned parameter preset range is stored in the power stage circuit 2011 or the fault diagnosis circuit 2012, or set by multiple external pins or by the external host 203. The method of controlling the first parameter P1 to a preset fixed value can be controlled by the feedback mechanism of the DC brushless motor drive circuit 201, such as, but not limited to, the rotational speed ω of the DC brushless motor 202; or it can be controlled by the fault diagnosis circuit 2012 sending a request signal, such as the motor temperature Tm, and so on.

[0081] like Figure 2AAs shown, the speed detection element 2013a is used to detect the speed ω and rotor angle θ of the brushless DC motor 202. The speed detection element 2013a is coupled to the commutation and PWM control circuit 2014 and the interface circuit 2015, thereby transmitting the rotor angle θ to the commutation and PWM control circuit 2014 and the speed ω of the brushless DC motor 202 to the interface circuit 2015. The brushless DC motor drive circuit 201 is coupled to the external host 203 via an interface. In one embodiment, the aforementioned interface includes a communication bus or multiple dedicated pins (e.g., FG pins). Furthermore, the interface circuit 2015 is used to receive the input pulse width modulation (PWM) signal Inp from the external host 203, extract the duty cycle from it, and transmit the duty cycle D to the commutation and PWM control circuit 2014, and to transmit the abnormal warning information Wn received from the abnormal diagnosis circuit 2012 to the external host 203, and is coupled to the external host 203. The commutation and PWM control circuit 2014 generates PWM signals dUH, dUL, dVH, dVL, dWH, and dWL based on the rotor angle θ and duty cycle D, and is coupled to the speed detection element 2013a, the power stage circuit 2011, and the interface circuit 2015. The brushless DC motor 202 has multiple coils; taking a three-phase brushless DC motor as an example, the brushless DC motor 202 has, for example, U-phase, V-phase, and W-phase coils. Figure 2A Only a three-phase brushless DC motor is shown; however, this invention is not limited to three-phase brushless DC motors, but can also be applied to two-phase brushless DC motors, five-phase brushless DC motors, or other multi-phase brushless DC motors.

[0082] In one embodiment, the first parameter P1 includes at least one of the following plurality of motor parameters, and the second parameter P2 includes at least another of the following plurality of motor parameters: (1) the rotational speed ω of the brushless DC motor 202; (2) the motor temperature Tm; (3) the ambient temperature Te; (4) the input current Iin of the brushless DC motor 202; (5) the input voltage Vin of the brushless DC motor 202; and (6) the duty cycle D of the PWM signal. In one embodiment, the first parameter P1 and the second parameter P2 are different. For example, when the first parameter P1 is the rotational speed ω of the brushless DC motor 202, the second parameter P2 may be at least one of the following: motor temperature Tm, ambient temperature Te, input current Iin of the brushless DC motor 202, input voltage Vin of the brushless DC motor 202, and duty cycle D of the PWM signal. Similarly, when the first parameter P1 is the motor temperature Tm, the second parameter P2 can be at least one of the following: the rotational speed ω of the brushless DC motor 202, the ambient temperature Te, the input current Iin of the brushless DC motor 202, the input voltage Vin of the brushless DC motor 202, and the duty cycle D of the PWM signal, and so on. When the first parameter P1 is both the motor temperature Tm and the ambient temperature Te, the second parameter P2 can be at least one of the following: the rotational speed ω of the brushless DC motor 202, the input current Iin of the brushless DC motor 202, the input voltage Vin of the brushless DC motor 202, and the duty cycle D of the PWM signal, and so on.

[0083] In one embodiment, the preset range of parameters corresponding to the second parameter P2 is related to at least one of a plurality of motor parameters. The aforementioned preset range of parameters includes, but is not limited to, maximum speed (ωM), minimum speed (ωm), maximum input current (IinM), minimum input current (Iinm), maximum input voltage (VinM), minimum input voltage (Vinm), maximum motor temperature (TmM), minimum motor temperature (Tmm), maximum ambient temperature (TeM), minimum ambient temperature (Tem), maximum duty cycle (DM), and minimum duty cycle (Dm). For example, in one embodiment, the preset range of parameters corresponding to the duty cycle D of the PWM signal can be set based on at least one of the following: the speed ω of the brushless DC motor 202, the motor temperature Tm, the ambient temperature Te, the input current Iin of the brushless DC motor 202, the input voltage Vin of the brushless DC motor 202, and the duty cycle D of the PWM signal. Similarly, the preset range of parameters corresponding to the speed ω of the brushless DC motor 202 can be set according to at least one of the speed ω of the brushless DC motor 202, the motor temperature Tm, the ambient temperature Te, the input current Iin of the brushless DC motor 202, the input voltage Vin of the brushless DC motor 202, and the duty cycle D of the PWM signal, and so on.

[0084] In another embodiment, the preset range of the parameter corresponding to the duty cycle D of the PWM signal can also be determined by taking a fixed difference / percentage based on the characteristic curve between the duty cycle D of the PWM signal and the rotational speed ω of the brushless DC motor 202, or the motor temperature Tm, or the ambient temperature Te, or the input current Iin of the brushless DC motor 202, or the input voltage Vin of the brushless DC motor 202. Similarly, the preset range of the parameter corresponding to the rotational speed ω of the brushless DC motor 202 can also be determined by taking a fixed difference / percentage based on the characteristic curve between the rotational speed ω of the brushless DC motor 202 and the duty cycle D of the PWM signal, or the motor temperature Tm, or the ambient temperature Te, or the input current Iin of the brushless DC motor 202, or the input voltage Vin of the brushless DC motor 202, and so on. Figure 2B As shown, in this embodiment, the characteristic curve between the rotational speed ω of the brushless DC motor 202 and the duty cycle D of the PWM signal is used to determine the maximum and minimum rotational speeds (ωM and ωm) within the preset parameter range by taking a fixed difference / percentage. In another embodiment, the aforementioned preset parameter range can also be obtained from a lookup table. In one embodiment, the aforementioned lookup table can be stored in the power stage circuit 2011 or the fault diagnosis circuit 2012.

[0085] like Figure 2B As shown, when the duty cycle D is fixed, the abnormality diagnosis circuit 2012 detects the rotational speed ω. When the rotational speed ω is lower than the minimum rotational speed (ωm) or higher than the maximum rotational speed (ωM), it determines that the DC brushless motor 202 is in an abnormal rotational state and generates an abnormality warning message Wn to the interface circuit 2015.

[0086] The power stage circuit 2011 provides multiple operating currents Iu, Iv, and Iw to supply the corresponding U-phase, V-phase, and W-phase coils, thereby controlling the rotor rotation. The power stage circuit 2011 may include multiple half-bridge power elements to generate the corresponding operating currents. These half-bridge power elements include, for example, upper-bridge power elements Qh1, Qh2, and Qh3, and lower-bridge power elements Ql1, Ql2, and Ql3. Upper-bridge power element Qh1 is connected in series with lower-bridge power element Ql1, upper-bridge power element Qh2 is connected in series with lower-bridge power element Ql2, and upper-bridge power element Qh3 is connected in series with lower-bridge power element Ql3. Lower-bridge power elements Ql1, Ql2, and Ql3 are collectively coupled to a resistor Rcs, which is coupled to ground potential. Upper-bridge power elements Qh1, Qh2, and Qh3 are collectively coupled to the input voltage Vin. The nodes between the upper bridge power elements Qh1, Qh2, Qh3 and the lower bridge power elements Ql1, Ql2, Ql3 are respectively coupled to the corresponding phase inductors Lu, Lv, Lw in the DC brushless motor 202.

[0087] The DC brushless motor 202 includes the phase inductance Lu and phase resistance Ru of phase U, the phase inductance Lv and phase resistance Rv of phase V, and the phase inductance Lw and phase resistance Rw of phase W. The phase inductance Lu and phase resistance Ru are connected in series, the phase inductance Lv and phase resistance Rv are connected in series, and the phase inductance Lw and phase resistance Rw are connected in series. The phase resistances Ru, Rv, and Rw of each phase are coupled to the neutral point N.

[0088] Figure 3 This is a circuit diagram illustrating a DC brushless motor drive circuit according to another embodiment of the present invention. This embodiment is similar to... Figure 2A The difference in this embodiment lies in that the anomaly diagnosis circuit 2012 includes an anomaly diagnosis controller 20121, an analog-to-digital converter (ADC) 20122, and a multiplexer (MUX) 20123. Furthermore, the DC brushless motor drive circuit 201' in this embodiment also includes a motor temperature detection element 2013b, an ambient temperature detection element 2013c, a current detection element 2013d, and a voltage detection element 2013e. The speed detection element 2013a, motor temperature detection element 2013b, ambient temperature detection element 2013c, current detection element 2013d, and voltage detection element 2013e can be collectively referred to as the parameter detection element 2013. The power stage circuit 2011, speed detection element 2013a, commutation and PWM control circuit 2014, interface circuit 2015, DC brushless motor 202, and external host 203 in this embodiment are similar to... Figure 2A The power stage circuit 2011, speed detection element 2013a, commutation and PWM control circuit 2014, interface circuit 2015, DC brushless motor 202, and external host 203 are omitted in detail.

[0089] Motor temperature sensing element 2013b is used to detect the temperature Tm (also referred to as motor temperature) of the brushless DC motor 202, while ambient temperature sensing element 2013c is used to detect the ambient temperature Te. The ambient temperature referred to here is the circuit board temperature. Current sensing element 2013d is used to detect the input current Iin, while voltage sensing element 2013e is used to detect the input voltage Vin. Motor temperature sensing element 2013b, ambient temperature sensing element 2013c, current sensing element 2013d, and voltage sensing element 2013e are all coupled to the input terminal of multiplexer 20123. The output of the multiplexer 20123 is coupled to the input of the analog-to-digital converter (ADC) 20122. Thus, the ADC 20122 can convert one of the following parameters—temperature Tm, ambient temperature Te, input current Iin, and input voltage Vin of the brushless DC motor 202 detected by the motor temperature sensing element 2013b, ambient temperature sensing element 2013c, current sensing element 2013d, and voltage sensing element 2013e—into a digital signal and provide it to the fault diagnosis controller 20121.

[0090] The anomaly diagnosis controller 20121 is used to determine an abnormal rotation state of the brushless DC motor 202 based on a second parameter when the first parameter is controlled. It can also receive the rotational speed ω of the brushless DC motor 202 and the duty cycle D of the PWM signal from the interface circuit 2015. When the anomaly diagnosis controller 20121 determines that the brushless DC motor 202 has an abnormal rotation, it generates an anomaly warning message Wn to the interface circuit 2015. In one embodiment, the first parameter and the second parameter are related to the rotation of the brushless DC motor 202. In one embodiment, when the first parameter is controlled at a preset fixed value, the anomaly diagnosis controller 20121 determines the abnormal rotation state of the brushless DC motor 202 based on whether the second parameter exceeds a preset range. The operation of the anomaly diagnosis controller 20121 can be found in [reference needed]. Figure 2A The relevant description of the abnormal diagnosis circuit in 2012.

[0091] Figure 4 This is a circuit diagram illustrating a DC brushless motor drive circuit according to yet another embodiment of the present invention. This embodiment is similar to... Figure 3 The difference from the previous embodiment is that the DC brushless motor drive circuit 201" in this embodiment further includes a speed control element 2016. The power stage circuit 2011, fault diagnosis circuit 2012, parameter detection element 2013, commutation and PWM control circuit 2014, interface circuit 2015, DC brushless motor 202, and external host 203 in this embodiment are similar to... Figure 3The power stage circuit 2011, the abnormal diagnosis circuit 2012, the parameter detection element 2013, the commutation and PWM control circuit 2014, the interface circuit 2015, the DC brushless motor 202, and the external host 203 are omitted in detail.

[0092] The speed control element 2016 controls the speed ω of the brushless DC motor 202 to a fixed value based on a speed reference value ωref and the speed ω of the brushless DC motor 202 fed back by the speed detection element 2013a. It also generates a duty cycle D based on the difference between the speed reference value ωref and the speed ω of the brushless DC motor 202, and provides the duty cycle D to the commutation and PWM control circuit 2014. Therefore, when the first parameter, such as the speed ω of the brushless DC motor 202 mentioned above, is controlled to a preset fixed value, the fault diagnosis controller 20121 determines whether a second parameter (e.g., but not limited to, duty cycle D and / or input current Iin and / or input voltage Vin and / or temperature Tm of the brushless DC motor 202 and / or ambient temperature Te) exceeds a preset range of a parameter (e.g., but not limited to...). Figure 4 The abnormal rotation state of the DC brushless motor 202 is determined by the duty cycle minimum value Dm to the duty cycle maximum value DM, the input current minimum value Iinm to the input current maximum value IinM, the input voltage minimum value Vinnm to the input voltage maximum value VinM, the motor temperature minimum value Tmm to the motor temperature maximum value TmM, and the ambient temperature minimum value Tem to the ambient temperature maximum value TeM.

[0093] In other embodiments, one or more of the duty cycle D, input current Iin, input voltage Vin, temperature Tm of the brushless DC motor 202, and ambient temperature Te can also be controlled to a fixed value. The abnormality diagnosis controller 20121 determines the abnormal rotation state of the brushless DC motor 202 based on whether the second parameter (at least one of the parameters other than the parameters controlled to a fixed value, such as the rotational speed ω of the brushless DC motor 202, duty cycle D, input current Iin, input voltage Vin, temperature Tm of the brushless DC motor 202, and ambient temperature Te) exceeds a preset range corresponding to the second parameter.

[0094] Figure 5 This is a circuit diagram illustrating a brushless DC motor drive circuit according to another embodiment of the present invention. This embodiment is used to drive a brushless DC motor without a speed sensor. Therefore, this embodiment is similar to... Figure 3The difference in this embodiment is that the parameter detection element 2013' of the DC brushless motor drive circuit 201"' in this embodiment includes a speed estimation element 2013f, which is used to estimate the speed of the DC brushless motor 202 and the rotor angle of the DC brushless motor 202, and transmits the estimated speed ωe of the DC brushless motor 202 to the interface circuit 2015, and transmits the estimated rotor angle θe of the DC brushless motor 202 to the commutation and PWM control circuit 2014. Since this embodiment uses a DC brushless motor without a speed sensor, the speed estimation element 2013f is used instead of the speed detection element 2013a.

[0095] The power stage circuit 2011, fault diagnosis circuit 2012, motor temperature detection element 2013b, ambient temperature detection element 2013c, current detection element 2013d, voltage detection element 2013e, commutation and PWM control circuit 2014, interface circuit 2015, brushless DC motor 202, and external host 203 in this embodiment are similar to those in the present embodiment. Figure 3 The power stage circuit 2011, the abnormal diagnosis circuit 2012, the motor temperature detection element 2013b, the ambient temperature detection element 2013c, the current detection element 2013d, the voltage detection element 2013e, the commutation and PWM control circuit 2014, the interface circuit 2015, the DC brushless motor 202, and the external host 203 are omitted in detail.

[0096] As described above, the DC brushless motor drive circuit of the present invention can diagnose mechanical faults of the motor by monitoring the duty cycle, motor speed, motor input current, motor input voltage, motor temperature or ambient temperature, and can report warnings or errors of the motor status to an external host.

[0097] The present invention has been described above with reference to preferred embodiments. However, the above description is only intended to facilitate understanding of the invention by those skilled in the art and is not intended to limit the broadest scope of the invention. The described embodiments are not limited to individual application and can also be used in combination. For example, two or more embodiments can be used in combination, and some components of one embodiment can be used to replace corresponding components in another embodiment. Furthermore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations. For example, the phrase "processing or calculating based on a signal or generating an output result" in the present invention is not limited to the signal itself, but also includes, when necessary, performing voltage-to-current conversion, current-to-voltage conversion, and / or proportional conversion on the signal, and then processing or calculating based on the converted signal to generate an output result. Therefore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations, and there are many combinations, which will not be listed here. Therefore, the scope of the present invention should cover the above and all other equivalent changes.

Claims

1. A DC brushless motor drive circuit, comprising: A power stage circuit for driving a DC brushless motor according to a pulse width modulation signal; and An abnormality diagnosis circuit is used to determine an abnormal rotation state of the brushless DC motor based on a second parameter when a first parameter is controlled. in, The first parameter and the second parameter are related to the rotation of the brushless DC motor; The first parameter includes at least one of the following motor parameters, and the second parameter includes at least another of the following motor parameters: (1) The rotational speed of the brushless DC motor; (2) Motor temperature; (3) Ambient temperature; (4) The input current of the brushless DC motor; (5) One input voltage of the brushless DC motor; (6) The duty cycle of the pulse width modulation signal; The first parameter is different from the second parameter; when the first parameter is controlled to a preset fixed value, the abnormality diagnosis circuit determines the abnormal rotation state of the DC brushless motor based on whether the second parameter exceeds a preset range.

2. The DC brushless motor drive circuit as described in claim 1, wherein, The motor parameters are detected or estimated by a corresponding parameter detection element.

3. The DC brushless motor drive circuit as described in claim 2, wherein, The parameter detection element includes at least one of the following: (1) A speed detection element for detecting the speed of the brushless DC motor; (2) A motor temperature sensing element for detecting the temperature of the motor; (3) An ambient temperature sensing element for detecting the ambient temperature; (4) A current sensing element for detecting the input current; (5) A voltage sensing element for detecting the input voltage; (6) A speed estimation element for estimating the speed of the brushless DC motor.

4. The DC brushless motor drive circuit as described in claim 1, wherein, The parameter preset range corresponding to the second parameter relates to at least one of the plurality of motor parameters.

5. The DC brushless motor drive circuit as described in claim 1, wherein, When the first parameter is the rotational speed of the brushless DC motor, the brushless DC motor drive circuit further includes a rotational speed detection element and a rotational speed control element. The rotational speed detection element is used to detect the rotational speed of the brushless DC motor, and the rotational speed control element is used to control the rotational speed of the brushless DC motor to the fixed value based on a rotational speed reference value and the rotational speed of the brushless DC motor fed back by the rotational speed detection element.

6. The DC brushless motor drive circuit as described in claim 1, wherein, The preset range of this parameter is stored in the power stage circuit or the fault diagnosis circuit, or is set by multiple external pins or by an external host.

7. The DC brushless motor drive circuit as described in claim 6, wherein, The brushless DC motor drive circuit is coupled to the external host via an interface that includes a communication bus or multiple dedicated pins.

8. The DC brushless motor drive circuit as described in claim 1, wherein, It also includes a commutation and pulse width modulation control circuit for generating the pulse width modulation signal based on a rotor angle and the duty cycle.

9. The DC brushless motor drive circuit as described in claim 8, wherein, It also includes a speed control element for generating the duty cycle based on the difference between a speed reference value and the speed of the brushless DC motor.

10. The DC brushless motor drive circuit as described in claim 1, wherein, The first parameter is the duty cycle of the pulse width modulation signal, and the second parameter is the rotational speed of the brushless DC motor.

11. The DC brushless motor drive circuit as described in claim 1, wherein, The first parameter is the duty cycle of the pulse width modulation signal, and the second parameter is the motor temperature and / or the ambient temperature.

12. The DC brushless motor drive circuit as described in claim 1, wherein, The first parameter is the input current of the brushless DC motor, and the second parameter is the rotational speed of the brushless DC motor.

13. The DC brushless motor drive circuit as described in claim 1, wherein, The first parameter is the input current, and the second parameter is the motor temperature and / or the ambient temperature.

Images