Calibration method, device and equipment of brushless direct current motor and storage medium

Abstract

The application provides a calibration method, device and equipment of a brushless direct current motor and a storage medium, and relates to the technical field of direct current motors. The method comprises the following steps: determining whether the comparison threshold of each phase winding is calibrated according to the calibration data of the phase windings, the comparison threshold of each phase winding being used for back electromotive force zero-crossing detection of the phase windings; if the comparison threshold corresponding to each phase winding is calibrated, input voltage parameters of the phase windings are obtained; according to the input voltage parameters of the phase windings and corresponding neutral point correction constants, target neutral point voltage parameters corresponding to the phase windings are determined, so that the comparison threshold of the phase windings is set according to the target neutral point voltage parameters. Compared with the prior art, the control error caused by the parameter imbalance between the phase windings of the motor is avoided, and the problem of affecting the control efficiency of the brushless direct current motor is solved.

Description

Technical Field

[0001] This application relates to the field of DC motor technology, and more specifically, to a calibration method, apparatus, device, and storage medium for a brushless DC motor. Background Technology

[0002] Nowadays, brushless DC motors and their components are increasingly used in our daily lives and industrial production. A brushless DC motor consists of a motor body and a driver, and is a typical mechatronic product. A brushless motor refers to a motor without brushes and a commutator (or slip rings), also known as a commutatorless motor.

[0003] Compared to brushed motors, brushless DC motors offer advantages such as lower noise, longer lifespan, and more diverse control methods. Compared to permanent magnet synchronous motors, they offer advantages such as lower cost and simpler control. Existing control methods and circuits are designed based on the assumption that the parameters between each phase winding of a brushless DC motor are consistent.

[0004] However, during the production of brushless DC motors, due to batch differences and manufacturing errors, some motors may exhibit unequal winding parameters, i.e., winding imbalance. If it is assumed that the parameters of each phase winding of a brushless DC motor are consistent, control errors will arise due to parameter imbalance between the motor's phase windings, affecting the control efficiency of the brushless DC motor. Summary of the Invention

[0005] The purpose of this application is to address the shortcomings of the prior art by providing a calibration method, apparatus, device, and storage medium for a brushless DC motor, thereby solving the problem of control errors caused by parameter imbalance between the windings of different phases of the motor, which affects the control efficiency of the brushless DC motor.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In a first aspect, one embodiment of this application provides a calibration method for a brushless DC motor, the method comprising: Obtain calibration data for each phase winding in a brushless DC motor; Based on the calibration data of each phase winding, determine whether the comparison threshold of each phase winding has been calibrated. The comparison threshold of each phase winding is used to perform back EMF zero-crossing detection on each phase winding. If the comparison thresholds corresponding to each phase winding are all calibrated, then the input voltage parameters of each phase winding are obtained. Based on the input voltage parameters of each phase winding and the corresponding neutral point correction constant, the target neutral point voltage parameters corresponding to each phase winding are determined, so as to set the comparison threshold of each phase winding according to the target neutral point voltage parameters.

[0007] Optionally, before obtaining the input voltage parameters of each phase winding, the method further includes: Based on the input voltage of each phase winding and the corresponding initial neutral point voltage, the neutral point correction constant corresponding to each phase winding is determined.

[0008] Optionally, the method further includes: If any of the phase windings has an uncalibrated winding to be calibrated, the motor is controlled to stop working; wherein, the winding to be calibrated is in a floating state; Obtain the input voltage at the port of the winding to be calibrated; The neutral point correction constant corresponding to the winding to be calibrated is determined based on the input voltage and the initial neutral point voltage corresponding to the winding to be calibrated. The calibration data of each phase winding is updated based on the neutral point correction constant.

[0009] Optionally, obtaining the input voltage at the port of the winding to be calibrated includes: Detect the current parameters on the two windings other than the one to be calibrated; If the stabilization time of the current parameters on the other two windings is greater than a preset time threshold, then the input voltage of the winding to be calibrated is obtained.

[0010] Optionally, after the motor is stopped from operating, the method further includes: The initial neutral point voltage corresponding to the winding to be calibrated is obtained from the input voltage detection unit.

[0011] Optionally, determining the neutral point correction constant corresponding to the winding to be calibrated based on the input voltage and the initial neutral point voltage corresponding to the winding to be calibrated includes: The ratio between the initial neutral point voltage corresponding to the winding to be calibrated and the input voltage is determined as the neutral point correction constant corresponding to the winding to be calibrated.

[0012] Optionally, before controlling the motor to stop working if there are uncalibrated windings among the phase windings, the method further includes: According to the testing instructions, identify the winding to be calibrated among all the windings; Alternatively, one winding from each winding can be selected as the winding to be calibrated.

[0013] Secondly, another embodiment of this application provides a calibration device for a brushless DC motor, the device comprising: an acquisition module and a determination module, wherein: The acquisition module is used to acquire calibration data of each phase winding in the brushless DC motor; The determining module is used to determine whether the comparison threshold of each phase winding has been calibrated based on the calibration data of each phase winding. The comparison threshold of each phase winding is used to perform back EMF zero-crossing detection on each phase winding. The acquisition module is specifically used to acquire the input voltage parameters of each phase winding if the comparison thresholds corresponding to each phase winding have been calibrated. The determining module is specifically used to determine the target neutral point voltage parameter corresponding to each phase winding based on the input voltage parameter of each phase winding and the corresponding neutral point correction constant, so as to set the comparison threshold of each phase winding according to the target neutral point voltage parameter.

[0014] Optionally, the determining module is specifically used to determine the neutral point correction constant corresponding to each phase winding based on the input voltage of each phase winding and the corresponding initial neutral point voltage; and to update the calibration data of each phase winding based on the neutral point correction constant.

[0015] Optionally, the device further includes: a control module, used to control the motor to stop working if there is an uncalibrated winding to be calibrated in each phase winding; wherein the winding to be calibrated is in a floating state; The acquisition module is specifically used to acquire the input voltage of the port of the winding to be calibrated; The determination module is specifically used to determine the neutral point correction constant corresponding to the winding to be calibrated based on the input voltage and the initial neutral point voltage corresponding to the winding to be calibrated.

[0016] Optionally, the device further includes: a detection module for detecting current parameters on two windings other than the winding to be calibrated; The acquisition module is specifically used to acquire the input voltage of the winding to be calibrated if the stabilization time of the current parameters on the other two windings is greater than a preset time threshold.

[0017] Optionally, the acquisition module is specifically used to acquire the initial neutral point voltage corresponding to the winding to be calibrated sent by the input voltage detection unit.

[0018] Optionally, the determining module is specifically used to determine the ratio between the initial neutral point voltage corresponding to the winding to be calibrated and the input voltage as the neutral point correction constant corresponding to the winding to be calibrated.

[0019] Optionally, the determining module is specifically used to determine the winding to be calibrated among the windings according to the detection instruction; or, sequentially determine one winding among the windings as the winding to be calibrated.

[0020] Thirdly, another embodiment of this application provides a motor control system, the system comprising: a control unit, an input voltage detection unit, a digital-to-analog converter, a first comparator, an inverter unit, and a load motor; wherein, the input voltage detection unit is electrically connected to the control unit and is used to detect the input voltage of the inverter unit in real time; one end of the digital-to-analog converter is electrically connected to the control unit and the other end is electrically connected to the first comparator, and is used to convert the comparison threshold of the first comparator into an analog quantity and transmit it to the first comparator; one end of the inverter unit is electrically connected to the control unit and the other end is electrically connected to the load motor, and is used to determine the voltage form on the load motor; the control unit is used to execute the steps of any of the methods described in the first aspect above.

[0021] Optionally, the input voltage detection unit includes an analog-to-digital converter; or, the input voltage detection unit includes a digital-to-analog converter and a second comparator.

[0022] The beneficial effects of this application are as follows: Using the calibration method for the brushless DC motor provided in this application, since the comparison thresholds of each phase winding in the brushless DC motor are calibrated before the motor starts, even if there are errors between the winding resistance values ​​and the calibration values ​​in the three-phase windings, the method provided in this application ensures that the comparison thresholds of each winding are calibrated during subsequent use of the brushless DC motor. This eliminates the problem of parameter imbalance in the three-phase windings, avoids control errors caused by imbalance, thereby improving the control efficiency of the brushless DC motor and preventing the problem of the brushless DC motor failing to start normally due to errors. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic flowchart illustrating a calibration method for a brushless DC motor provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a motor control system provided in an embodiment of this application; Figure 3 A schematic flowchart of a calibration method for a brushless DC motor provided in another embodiment of this application; Figure 4 This is a schematic diagram of the structure of each winding in a brushless DC motor provided in an embodiment of this application; Figure 5 This is a schematic diagram of the structure of each winding in a brushless DC motor provided in an embodiment of this application; Figure 6 A schematic flowchart of a calibration method for a brushless DC motor provided in another embodiment of this application; Figure 7 This is a schematic diagram of the structure of a calibration device for a brushless DC motor provided in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of a calibration device for a brushless DC motor provided in another embodiment of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0026] The components of the embodiments of this application described and illustrated in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] Furthermore, the flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed in order or performed simultaneously. Moreover, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0028] The following explanation, using several specific application examples, illustrates a calibration method for a brushless DC motor provided in this application. Figure 1 This is a schematic flowchart illustrating a calibration method for a brushless DC motor according to an embodiment of this application. Figure 2 This is a schematic diagram of the structure of a motor control system provided in an embodiment of this application, as shown below. Figure 1 As shown, the method includes: S101: Obtain calibration data for each phase winding in a brushless DC motor.

[0029] In the embodiments of this application, the above method is applied to the control unit in a motor control system, such as... Figure 2As shown, the motor control system includes: a control unit, an input voltage detection unit, a digital-to-analog converter, a load motor phase voltage detection unit, an inverter unit, and a load motor; wherein, the input voltage detection unit is electrically connected to the control unit and is used to detect the input voltage of the inverter unit in real time; one end of the digital-to-analog converter is electrically connected to the control unit, and the other end is electrically connected to the first comparator and the load motor phase voltage detection unit, and is used to convert the comparison threshold of the first comparator into an analog quantity and transmit it to the load motor phase voltage detection unit; one end of the inverter unit is electrically connected to the control unit, and the other end is electrically connected to the load motor, and is used to determine the voltage form on the load motor; the control unit is used to execute the calibration method for the brushless DC motor provided in this application.

[0030] In some possible embodiments, the input voltage detection unit is used to detect the input voltage of the inverter unit in real time. After detecting the input voltage signal of the inverter unit, the input voltage detection unit sends it to the control unit. The input voltage detection unit can be an analog-to-digital conversion device, such as an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), and a comparator.

[0031] The control unit is used to acquire calibration information of the three-phase winding imbalance of the brushless DC motor; the controller is also used to receive the detection data of the load motor phase voltage detection unit, perform back EMF zero crossing judgment and comparator voltage threshold calibration, the control unit is also used to output pulse width modulation (PWM) signal to the inverter unit; in addition, the control unit is also used to output the digital quantity corresponding to the first comparator voltage threshold to the digital-to-analog converter.

[0032] The digital-to-analog converter unit is used to convert the digital quantity corresponding to the voltage threshold signal of the first comparator into the corresponding analog quantity and provide it to the load motor phase voltage detection unit.

[0033] Load motor phase voltage detection unit: used to detect data during the unbalance detection phase when the load motor is stopped. This detection phase can be performed by combining a DAC and a comparator, or directly by an ADC to acquire data in real time when the voltage is fixed. In addition, it is also used for zero-crossing detection of back EMF during the operation of the load motor.

[0034] The inverter unit is used to control different switching combinations of the switching transistors to generate an equivalent sinusoidal or square wave voltage on the stator winding of the load motor through the PWM signal generated by the PWM modulation unit.

[0035] S102: Based on the calibration data of each phase winding, determine whether the comparison threshold of each phase winding has been calibrated.

[0036] The comparison threshold for each phase winding is used to detect the back EMF zero crossing of each phase winding.

[0037] During the production of brushless DC motors, due to batch differences and manufacturing errors, some motors may exhibit unequal winding parameters, i.e., winding imbalance. This can lead to control errors. To avoid the impact of control errors on the control efficiency of brushless DC motors, in the embodiments of this application, each phase winding needs to be calibrated before it can be put into normal use. Therefore, before normal use, it is necessary to determine whether each phase winding has been calibrated to ensure the accuracy of subsequent work and thus improve work efficiency.

[0038] S103: If the comparison thresholds corresponding to each phase winding have been calibrated, then obtain the input voltage parameters of each phase winding.

[0039] In some possible embodiments, the neutral point correction constant corresponding to each phase winding is determined based on the input voltage of each phase winding and the corresponding initial neutral point voltage. For example, the determination method can be based on the ratio of the parameter value of the initial neutral point voltage of each winding to the parameter value of the corresponding input voltage.

[0040] In other words, after the brushless DC motor starts, taking windings A, B, and C as an example, the digital quantity corresponding to the current input voltage V1 of each phase winding is obtained by the input voltage analog-to-digital converter unit as the input voltage parameter. , , .

[0041] S104: Determine the target neutral point voltage parameters for each phase winding based on the input voltage parameters of each phase winding and the corresponding neutral point correction constant, so as to set the comparison threshold of each phase winding according to the target neutral point voltage parameters. For example, let's take determining the target neutral point voltage parameters of winding A as an example. This involves determining the voltage corresponding to winding A. Then, the input voltage Corresponding digital quantities and neutral point voltage parameters Multiply to obtain the target neutral point voltage at the current moment. The corresponding digital quantity, that is, the parameter for determining the neutral point voltage. Then The corresponding digital quantity is converted into an analog voltage by the motor neutral point digital-to-analog converter unit, which serves as the calibrated comparator threshold voltage to detect the zero-crossing back electromotive force of the A-phase winding (winding A) in the motor.

[0042] The calibration method for brushless DC motors provided in this application ensures that the comparison thresholds of each phase winding in the brushless DC motor are calibrated before startup. Even if there are errors between the winding resistance values ​​and the calibration values ​​in the three-phase windings, the method eliminates the problem of parameter imbalance during subsequent use, as the comparison thresholds of each winding are calibrated. This avoids control errors caused by imbalance, thereby improving the control efficiency of the brushless DC motor and preventing the motor from failing to start normally due to errors.

[0043] Optionally, based on the above embodiments, this application embodiment can also provide a calibration method for a brushless DC motor. The implementation process of the above method is illustrated below with reference to the accompanying drawings. Figure 3 A schematic flowchart of a calibration method for a brushless DC motor, as provided in another embodiment of this application, is shown below. Figure 3 As shown, before S103, the method may further include: S111: If there are uncalibrated windings in each phase winding, the motor will stop working.

[0044] The winding to be calibrated is in a floating state.

[0045] If there are uncalibrated windings among the windings, it indicates that there may be a problem that the resistance value of the winding in the current brushless DC motor is inconsistent with the calibration value. In this case, it is necessary to calibrate the uncalibrated windings in the brushless DC motor. During calibration, the motor needs to be stopped, the state of the winding to be calibrated is set to floating, and DC voltage is continuously applied to the other two windings besides the winding to be calibrated.

[0046] For example, in an embodiment of this application, after the control motor stops working, it is also necessary to obtain the initial neutral point voltage corresponding to the winding to be calibrated sent by the input voltage detection unit.

[0047] In some possible embodiments, the input voltage detection unit may include, for example, an analog-to-digital converter (ADC); in this case, the initial neutral point voltage corresponding to the winding to be calibrated can be directly acquired and obtained through the ADC. Alternatively, the input voltage detection unit may also include a digital-to-analog converter (DAC) and a second comparator; in this case, the initial neutral point voltage corresponding to the winding to be calibrated can be determined by the DAC and the second comparator through a successive approximation method. This acquisition method has relatively higher accuracy than directly acquiring the initial neutral point voltage corresponding to the winding to be calibrated through the ADC, thereby ensuring the accuracy of subsequent calculations and reducing calculation errors. It should be understood that the above embodiments are only illustrative examples, and the specific method for determining the initial neutral point voltage corresponding to the winding to be calibrated can be flexibly adjusted according to user needs and is not limited to the methods given in the above embodiments.

[0048] S112: Obtain the input voltage at the port of the winding to be calibrated.

[0049] In some possible embodiments, the input voltage of the port of the winding to be calibrated can be obtained by, for example, detecting the current parameters on the other two windings besides the winding to be calibrated; if the stabilization time of the current parameters on the other two windings is greater than a preset time threshold, it is determined that the current has reached its maximum value, and at this time the input voltage of the winding to be calibrated is obtained.

[0050] S113: Determine the neutral point correction constant corresponding to the winding to be calibrated based on the input voltage and the initial neutral point voltage corresponding to the winding to be calibrated.

[0051] One method for determining this is to use the ratio between the initial neutral point voltage and the input voltage to determine the neutral point correction constant corresponding to the winding to be calibrated.

[0052] In the embodiments of this application, if there are multiple uncalibrated windings to be calibrated, one winding is selected as the winding to be calibrated from among the uncalibrated windings in sequence, and multiple uncalibrated windings are calibrated in sequence until all windings of the brushless DC motor are calibrated. Then, it is determined that the three-phase winding parameter imbalance calibration of the brushless DC motor is completed. At this time, the motor is restored to a stationary state, and the calibration data of each phase winding is updated.

[0053] Example, Figure 4 This is a schematic diagram of the structure of each winding in a brushless DC motor according to an embodiment of this application. Figure 5 This is a schematic diagram of the structure of each winding in a brushless DC motor according to an embodiment of this application. The calibration principle for each phase winding provided in this application is as follows: Taking a brushless three-phase DC motor as an example, the inductance and resistance parameters of the A-phase winding of the load motor are consistent with the calibration values, while the parameters of at least one of the B-phase and C-phase windings deviate from those of the A-phase winding, meaning that there is a parameter imbalance in the three-phase windings of the motor.

[0054] When the back electromotive force of phase A is detected to be zero-crossing during the operation of the load motor, such as Figure 4 As shown, at this time, the A-phase winding of the load motor is in a floating state, that is, the current of the A-phase winding is 0. According to the motor stator voltage equation, the voltages across the B-phase and C-phase windings of the motor can be expressed as follows: ,in , , These are the equivalent resistances of the three-phase windings of the load motor, respectively. , , These are the equivalent inductances of the three-phase windings of the load motor. VBB is the bus voltage applied between phases B and C of the load motor, VN is the voltage between the neutral point of the three-phase winding and ground, and VA is the voltage between the terminals of phase A winding and ground. This refers to the current flowing through the B and C phase windings of the load motor. , These are the induced electromotive forces (back electromotive forces) generated by the rotor magnetic field of the load motor on the A, B, and C phase windings, respectively. During motor operation, the back electromotive forces on the three-phase windings satisfy the following relationship: + + =0; When the A-phase winding of the motor runs parallel to the stator magnetic field, there will be =0, meaning this is the zero-crossing point of the back electromotive force of the motor's A-phase winding, then we have + =0, the terminal voltage of the floating phase A winding of the motor Furthermore, the resistance, inductance, and back electromotive force of the motor windings are all directly proportional to the number of turns in the windings. Therefore, the above formula can be equivalent to... For a three-phase DC motor, the winding voltage and the motor speed are directly proportional, therefore the above formula can be transformed into: .

[0055] like Figure 5 As shown, under the same input voltage of the inverter bridge, when the load motor is in the stopped phase, as... Figure 5 The control unit controls the upper and lower switches of phase A of the motor to turn off, leaving it in a floating state. DC current is then supplied from phase B to phase C, causing the current in phases B and C to reach its maximum value and stabilize for a short period. During this time, the terminal voltage of the floating phase A is monitored. This detected voltage value is .in This is a constant, representing the correction constant for the actual neutral point of the motor; it is used when the three-phase winding parameters of the motor are balanced. = = hour, .

[0056] By way of example, it should be understood that the above embodiments are merely illustrative examples for detecting and correcting imbalances when it is already known which winding is unbalanced. In other possible embodiments, determining which winding to leave unbalanced during imbalance detection depends on the control method of the motor during operation. In some possible embodiments, the winding to be calibrated can be determined from among the windings according to the detection command. That is, if only the x-phase winding is subjected to back EMF zero-crossing detection during motor operation, then the x-phase winding is left unbalanced during imbalance detection, generating a neutral point correction constant. In other possible embodiments, one winding can be determined as the winding to be calibrated sequentially from among the windings. That is, if back EMF zero-crossing detection is performed on each phase winding during motor operation, then each phase winding is left unbalanced sequentially during imbalance detection, generating multiple neutral point correction constants.

[0057] Using the method provided in this application, this detection and correction method is feasible regardless of whether the three winding parameters of the motor are consistent. If the motor parameters are consistent, the result of this correction method is basically the same as the result without correction. If the motor parameters are inconsistent, the beneficial effect of this correction method is reflected, which can effectively improve the control error caused by the imbalance of the three-phase winding parameters of the motor during the operation of the brushless DC motor.

[0058] In some possible embodiments, the update method may be to update the calibration data in the storage unit, and the updated calibration data indicates that the three-phase winding parameters of the brushless DC motor have been calibrated. After the brushless DC motor is started, the calibration data of each phase winding (i.e., the neutral point correction constant) can be used directly.

[0059] Figure 6 The following is a flowchart illustrating a calibration method for a brushless DC motor according to another embodiment of this application. The method flow provided in this application will be explained below using a complete embodiment, taking as an example a brushless DC motor with three-phase windings including winding A, winding B, and winding C, where winding A is an uncalibrated winding to be calibrated: 121: Read data from the storage unit.

[0060] By reading the data in the storage unit, it can be determined whether the comparison threshold of the back EMF zero-crossing comparator of each phase winding in the brushless DC motor has been calibrated.

[0061] 122: Determine whether all phase windings in the brushless DC motor have been calibrated.

[0062] If all phase windings in the brushless DC motor have been calibrated, proceed to step 128; if there is at least one uncalibrated winding in the brushless DC motor, proceed to step 123 to begin the detection and calibration of the comparison threshold of the back EMF zero-crossing comparator.

[0063] 123: When the motor is stopped, the switching transistors controlling the inverter will suspend the winding A to be calibrated in the brushless DC motor, and continuously apply DC voltage to windings B and C.

[0064] The applied DC voltage can be, for example, the detection voltage Vref.

[0065] 124: Wait for the current in windings B and C of the brushless DC motor to reach its maximum value and then stabilize for a short period of time.

[0066] 125: Obtain the digital quantity corresponding to the applied detection voltage Vref through the input voltage detection unit.

[0067] One possible method is to obtain the digital value corresponding to the current neutral point voltage VNref of the motor by means of a motor neutral point digital-to-analog converter unit + comparator CMP in a successive approximation manner; and to obtain the digital value corresponding to the applied detection voltage Vref by means of an input voltage analog-to-digital converter unit.

[0068] 126: The ratio of the digital quantity corresponding to the neutral point voltage VNref to the digital quantity corresponding to the detection voltage Vref is denoted as a constant k.

[0069] Among them, the constant K is the neutral point correction constant; each phase winding in a brushless DC motor has its own corresponding constant k, and the value of the constant k for different windings may be different.

[0070] 127: The three-phase winding parameter imbalance calibration of the brushless DC motor is completed. The motor is restored to a stationary state and the memory unit is written.

[0071] This indicates that the calibration of the unbalanced neutral point of the brushless DC motor has been completed.

[0072] 128: After the brushless DC motor starts, the digital quantity corresponding to the input voltage V1 of the current winding A is obtained through the input voltage analog-to-digital conversion unit.

[0073] 129: Multiply the digital value corresponding to the input voltage V1 of winding A with the constant k of winding A to obtain the digital value corresponding to the target neutral point voltage VN of winding A at the current moment.

[0074] 130: The digital quantity corresponding to VN is converted into an analog voltage by the motor neutral point digital-to-analog converter unit, and used as the calibrated first comparator threshold voltage for zero-crossing detection of the back EMF of the motor A-phase winding.

[0075] The calibration method for brushless DC motors provided in this application determines the neutral point correction constant for each phase winding based on the input voltage and corresponding initial neutral point voltage of each phase winding. Then, the initial neutral point voltage of the electromotive force zero-crossing detection is detected and corrected based on the neutral point correction constant to obtain the corrected target neutral point correction constant. This method effectively improves the control error caused by parameter imbalance of the three-phase windings during the operation of the brushless DC motor. Furthermore, the method provided in this application can acquire the initial neutral point voltage of the motor even when it is in standby mode. The process is simple and does not affect the actual operation of the motor.

[0076] The calibration device for a brushless DC motor provided in this application will be explained below with reference to the accompanying drawings. This calibration device for a brushless DC motor can perform the above-described... Figures 1-6 The calibration method for any brushless DC motor, its specific implementation and beneficial effects are as described above, and will not be repeated below.

[0077] Figure 7 This is a schematic diagram of the structure of a calibration device for a brushless DC motor provided in an embodiment of this application, as shown below. Figure 7 As shown, the device includes: an acquisition module 201 and a determination module 202, wherein: The acquisition module 201 is used to acquire the calibration data of each phase winding in the brushless DC motor; The determination module 202 is used to determine whether the comparison threshold of each phase winding has been calibrated based on the calibration data of each phase winding. The comparison threshold of each phase winding is used to perform back EMF zero crossing detection on each phase winding. The acquisition module 201 is specifically used to acquire the input voltage parameters of each phase winding if the comparison thresholds corresponding to each phase winding have been calibrated. The determination module 202 is specifically used to determine the target neutral point voltage parameters of each phase winding based on the input voltage parameters of each phase winding and the corresponding neutral point correction constant, so as to set the comparison threshold of each phase winding according to the target neutral point voltage parameters.

[0078] Optionally, the determining module 202 is specifically used to determine the neutral point correction constant corresponding to each phase winding based on the input voltage of each phase winding and the corresponding initial neutral point voltage; and to update the calibration data of each phase winding based on the neutral point correction constant.

[0079] Optionally, based on the above embodiments, this application embodiment may also provide a calibration device for a brushless DC motor, as described below with reference to the accompanying drawings. Figure 7 The implementation process of the given device is illustrated with examples. Figure 8 This is a schematic diagram of the structure of a calibration device for a brushless DC motor provided in another embodiment of this application, as shown below. Figure 8 As shown, the device also includes a control module 203, which controls the motor to stop working if there is an uncalibrated winding to be calibrated in each phase winding; wherein the winding to be calibrated is in a floating state. The acquisition module 201 is specifically used to acquire the input voltage of the port of the winding to be calibrated; The determination module 202 is specifically used to determine the neutral point correction constant corresponding to the winding to be calibrated based on the input voltage and the initial neutral point voltage corresponding to the winding to be calibrated.

[0080] Optionally, such as Figure 8 As shown, the device also includes: a detection module 204, used to detect the current parameters on the two windings other than the one to be calibrated; The acquisition module 201 is specifically used to acquire the input voltage of the winding to be calibrated if the stabilization time of the current parameters on the other two windings is greater than a preset time threshold.

[0081] Optionally, the acquisition module 201 is specifically used to acquire the initial neutral point voltage corresponding to the winding to be calibrated sent by the input voltage detection unit.

[0082] Optionally, the determining module 202 is specifically used to determine the ratio between the initial neutral point voltage corresponding to the winding to be calibrated and the input voltage as the neutral point correction constant corresponding to the winding to be calibrated.

[0083] Optionally, the determining module 202 is specifically used to determine the winding to be calibrated among the windings according to the detection instruction; or, sequentially determine one winding among the windings as the winding to be calibrated.

[0084] The above-described device is used to execute the method provided in the foregoing embodiments, and its implementation principle and technical effect are similar, so they will not be described again here.

[0085] These modules can be one or more integrated circuits configured to implement the above methods, such as one or more Application Specific Integrated Circuits (ASICs), one or more microprocessors, or one or more Field Programmable Gate Arrays (FPGAs). Alternatively, when a module is implemented using processing element scheduler code, the processing element can be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor capable of calling program code. Furthermore, these modules can be integrated together as a system-on-a-chip (SOC).

[0086] Optionally, this application also provides a program product, such as a storage medium storing a computer program, including a program that executes the embodiments corresponding to the above-described methods when run by a processor.

[0087] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0088] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0089] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in a combination of hardware and software functional units.

[0090] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A calibration method for a brushless DC motor, characterized in that, The method includes: If there is an uncalibrated winding in any phase winding, the motor is controlled to stop working; wherein, the state of the winding to be calibrated is floating. Obtain the input voltage at the port of the winding to be calibrated; The neutral point correction constant corresponding to the winding to be calibrated is determined based on the input voltage and the initial neutral point voltage corresponding to the winding to be calibrated. The calibration data of each phase winding is updated according to the neutral point correction constant; the calibration data includes the neutral point correction constant corresponding to each phase winding. After the brushless DC motor is started, the calibration data of each phase winding in the brushless DC motor is acquired; Based on the calibration data of each phase winding, determine whether the comparison threshold of each phase winding has been calibrated. The comparison threshold of each phase winding is used to perform back EMF zero-crossing detection on each phase winding. If the comparison thresholds corresponding to each phase winding are all calibrated, then the input voltage parameters of each phase winding are obtained. Based on the input voltage parameters of each phase winding and the corresponding neutral point correction constant, the target neutral point voltage parameters corresponding to each phase winding are determined, so as to set the comparison threshold of each phase winding according to the target neutral point voltage parameters.

2. The method as described in claim 1, characterized in that, Before obtaining the input voltage parameters of each phase winding, the method further includes: Based on the input voltage of each phase winding and the corresponding initial neutral point voltage, the neutral point correction constant corresponding to each phase winding is determined.

3. The method as described in claim 1, characterized in that, The step of obtaining the input voltage at the port of the winding to be calibrated includes: Detect the current parameters on the two windings other than the one to be calibrated; If the stabilization time of the current parameters on the other two windings is greater than a preset time threshold, then the input voltage of the winding to be calibrated is obtained.

4. The method as described in claim 1, characterized in that, After the motor is stopped from operating, the method further includes: The initial neutral point voltage corresponding to the winding to be calibrated is obtained from the input voltage detection unit.

5. The method as described in claim 1, characterized in that, The step of determining the neutral point correction constant corresponding to the winding to be calibrated based on the input voltage and the initial neutral point voltage corresponding to the winding to be calibrated includes: The ratio between the initial neutral point voltage corresponding to the winding to be calibrated and the input voltage is determined as the neutral point correction constant corresponding to the winding to be calibrated.

6. The method as described in claim 1, characterized in that, If there are uncalibrated windings among the phase windings, before controlling the motor to stop working, the method further includes: According to the testing instructions, identify the winding to be calibrated among all the windings; Alternatively, one winding from each winding can be selected as the winding to be calibrated.

7. A calibration device for a brushless DC motor, characterized in that, The device includes: an acquisition module, a determination module, and a control module, wherein: The control module is used to control the motor to stop working if there is an uncalibrated winding to be calibrated in each phase winding; wherein the state of the winding to be calibrated is floating. The acquisition module is specifically used to acquire the input voltage of the port of the winding to be calibrated; The determining module is specifically used to determine the neutral point correction constant corresponding to the winding to be calibrated based on the input voltage and the initial neutral point voltage corresponding to the winding to be calibrated. The acquisition module is used to acquire calibration data of each phase winding in the brushless DC motor after the brushless DC motor is started. The determining module is used to determine whether the comparison threshold of each phase winding has been calibrated based on the calibration data of each phase winding. The comparison threshold of each phase winding is used to perform back EMF zero-crossing detection on each phase winding. The acquisition module is specifically used to acquire the input voltage parameters of each phase winding if the comparison thresholds corresponding to each phase winding have been calibrated. The determining module is specifically used to determine the target neutral point voltage parameter corresponding to each phase winding based on the input voltage parameter of each phase winding and the corresponding neutral point correction constant, so as to set the comparison threshold of each phase winding according to the target neutral point voltage parameter.

8. A motor control system, characterized in that, The system includes: a control unit, an input voltage detection unit, a digital-to-analog converter, a load motor phase voltage detection unit, an inverter unit, and a load motor; wherein, the input voltage detection unit is electrically connected to the control unit and is used to detect the input voltage of the inverter unit in real time; one end of the digital-to-analog converter is electrically connected to the control unit and the other end is electrically connected to the load motor phase voltage detection unit, and is used to convert the comparison threshold of the first comparator into an analog quantity and transmit it to the load motor phase voltage detection unit; one end of the inverter unit is electrically connected to the control unit and the other end is electrically connected to the load motor, and is used to determine the voltage form on the load motor; The control unit is used to perform the method described in any one of claims 1-6.

9. The system as described in claim 8, characterized in that, The input voltage detection unit includes: an analog-to-digital converter, a digital-to-analog converter, and a second comparator; it is used to obtain the neutral point voltage parameters of the motor by successive approximation through the digital-to-analog converter and the second comparator; and to obtain the input voltage parameters of each phase winding through the analog-to-digital converter.

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