WO2024051227A1

WO2024051227A1 - Control method and apparatus, and storage medium

Info

Publication number: WO2024051227A1
Application number: PCT/CN2023/098313
Authority: WO
Inventors: 周严鉴; 杨雷
Original assignee: 广东美的白色家电技术创新中心有限公司; 美的集团股份有限公司
Priority date: 2022-09-07
Filing date: 2023-06-05
Publication date: 2024-03-14
Also published as: CN116317817A

Abstract

Disclosed in the embodiments of the present application is a control method. The method is used for controlling a BLDCM. A driving circuit of the BLDCM comprises a DC-DC converter and a three-phase inverter. The method comprises: acquiring a target value of a parameter to be controlled of a BLDCM; on the basis of the target value, adjusting both the current duty ratio of a DC-DC converter and the current turning-on length of a switch tube of a three-phase inverter, so as to obtain a target duty ratio of the DC-DC converter and a target turning-on length of the switch tube in the three-phase inverter, wherein the current turning-on length and the target turning-on length are turning-on lengths with respect to an electrical angle of the BLDCM; and controlling the DC-DC converter on the basis of the target duty ratio, and controlling the three-phase inverter on the basis of the target turning-on length, so as to drive the BLDCM. Further disclosed in the embodiments of the present application are a control apparatus and a storage medium.

Description

A control method, device and storage medium

Cross-references to related applications

This application is filed based on the Chinese patent application with application number 202211088835.8 and the filing date is September 7, 2022, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby incorporated into this application as a reference.

Technical field

This application relates to the field of control technology of brushless direct current motor (BLDCM), and in particular to a control method, device and storage medium.

Background technique

At present, BLDCM usually adjusts the PWM duty cycle to adjust the motor power/speed, or uses PAM technology to control the inverter bridge by adjusting the duty cycle of the buck circuit to achieve an effect similar to adjusting the PWM duty cycle in BLDCM. The input voltage is used to adjust the motor power/speed. However, in the above scheme, the adjustment range of the BLDCM power/speed is very limited.

Contents of the invention

The embodiments of the present application are expected to provide a control method, device and storage medium to solve the problem in the related art that the power/speed adjustment range of BLDCM is very limited.

The technical solution of this application is implemented as follows:

A control method, the method is used to control a BLDCM, the hardware drive circuit of the BLDCM includes: a DC-DC converter and a three-phase inverter, including:

Obtain the target value of the parameter to be controlled of the BLDCM;

Based on the target value, the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter are respectively adjusted to obtain the target duty cycle of the DC-DC converter. The empty ratio and the target conduction length of the switching tube in the three-phase inverter; wherein the current conduction length and the target conduction length are the conduction lengths relative to the electrical angle of the BLDCM;

The DC-DC converter is controlled based on the target duty cycle, and the three-phase inverter is controlled based on the target conduction length to drive the BLDCM.

A control device, the device is used to control a BLDCM, the hardware drive circuit of the BLDCM includes: a DC-DC converter and a three-phase inverter, including:

An acquisition module, used to acquire the target value of the parameter to be controlled by the BLDCM;

an adjustment module, configured to respectively adjust the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter based on the target value to obtain the DC-DC The target duty cycle of the converter and the target conduction length of the switching tube in the three-phase inverter; wherein the current conduction length and the target conduction length are conduction relative to the electrical angle of the BLDCM. pass length;

A control module configured to control the DC-DC converter based on the target duty cycle, and control the three-phase inverter based on the target conduction length to drive the BLDCM.

A control device including:

A processor and a storage medium storing instructions executable by the processor. The storage medium relies on the processor to perform operations through a communication bus. When the instructions are executed by the processor, one or more of the above are executed. The control method described in the embodiment.

A storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the control method described in one or more embodiments above.

The control method, device and storage medium provided by the embodiment of the present application are used to control BLDCM. The hardware driver circuit of BLDCM includes: DC-DC converter and three-phase inverter, including: obtaining the BLDCM to be controlled Based on the target value of the parameter, the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter are adjusted respectively to obtain the target duty cycle and The target conduction length of the switching tube in the three-phase inverter; where the current conduction length and the target conduction length are the conduction lengths relative to the electrical angle of the BLDCM, and the DC-DC converter is controlled based on the target duty cycle, based on The target conduction length controls the three-phase inverter to drive the BLDCM; that is to say, in the embodiment of the present application, the current duty cycle of the DC-DC converter is respectively adjusted based on the acquired target value of the parameter to be controlled. By adjusting the current conduction length of the switch tube of the three-phase inverter, the target duty cycle of the DC-DC converter and the target conduction length of the switch tube in the three-phase inverter can be obtained, and based on this, the BLDCM Control is performed so that the controlled parameters of the BLDCM are getting closer and closer to the target value. Here, the target value is used not only to adjust the duty cycle of the DC-DC converter, but also to adjust the conduction length of the switching tube of the three-phase inverter. Adjustment is made such that after the output voltage of the DC-DC converter is minimum, the effective value of the phase current of the BLDCM can be further reduced, thereby achieving the purpose of expanding the power/speed adjustment range, that is, increasing the power/speed of the BLDCM. Adjustment range of rotational speed.

Description of the drawings

Figure 1 is a schematic flowchart of an optional control method provided by an embodiment of the present application;

Figure 2 is a schematic diagram of an optional BLDCM control provided by an embodiment of the present application;

Figure 3a is a schematic flowchart of Example 1 of an optional control method provided by the embodiment of the present application;

Figure 3b is a schematic flowchart of Example 2 of an optional control method provided by the embodiment of the present application;

Figure 4a is a schematic flow chart of Example 1 of an optional control parameter provided by the embodiment of the present application;

Figure 4b is a schematic flow chart of Example 2 of an optional control parameter provided by the embodiment of the present application;

Figure 5a is a schematic flowchart of Example 3 of an optional control method provided by the embodiment of the present application;

Figure 5b is a schematic flowchart of Example 4 of an optional control method provided by the embodiment of the present application;

Figure 6 is a schematic diagram of optional BLDCM control parameters provided by an embodiment of the present application;

Figure 7 is a waveform diagram of the phase current of an optional BLDCM provided by the embodiment of the present application;

Figure 8 is a schematic structural diagram of an optional control device provided by an embodiment of the present application;

Figure 9 is a schematic structural diagram of another optional control device provided by an embodiment of the present application.

Detailed ways

In order to better understand the purpose, structure and function of the present application, an example of the present application is described below in conjunction with the accompanying drawings. The control method, device and storage medium are described in further detail.

Embodiments of the present application provide a control method for controlling BLDCM. The driving circuit of the BLDCM may include: a DC-DC converter and a three-phase inverter. Figure 1 is provided by an embodiment of the present application. A schematic flow chart of an optional control method is shown in Figure 1. The method may include:

S101: Obtain the target value of the BLDCM parameter to be controlled;

At present, the commonly used high-speed motor control scheme is BLDCM control using PWM technology, especially the BLDCM control with 120-degree drive. However, because conventional BLDCM control technology needs to adjust the PWM duty cycle to adjust the motor speed/power, this will cause PWM The control frequency is much higher than the operating frequency of the motor itself. When the motor speed is very high, the PWM control frequency will be too high. This will not only significantly increase the switching loss and cost of the inverter, but also require the BLDCM control system to The control parameter calculation is completed in a shorter control cycle, thereby increasing the cost and software design difficulty of the Microcontroller Unit (MCU).

In order to solve the above-mentioned conventional BLDCM control problems, a high-speed motor control scheme based on PAM (pulse amplitude adjustment) was proposed. Compared with the BLDCM control scheme, the PAM scheme requires a DC-DC converter at the front end of the inverter bridge. Therefore, the switching frequency of the inverter can be equal to the motor operating frequency in the PAM scheme, and the control strategy will be controlled by adjusting the duty cycle of the DC-DC converter (to achieve an effect similar to adjusting the PWM duty cycle in BLDCM). The input voltage of the inverter bridge is used to adjust the motor speed/power. Compared with the traditional BLDCM solution, the inverter bridge loss and cost in the PAM solution will be lower due to its lower switching frequency, and its requirements for MCU computing power are also lower, and these advantages will increase with the speed of the motor. It is more obvious with improvement, so PAM-based control schemes are used in many ultra-high-speed motor systems.

However, due to cost and size considerations, the front-end DC-DC converter circuit cannot reduce the output voltage (i.e., the inverter input voltage) to a small enough level, resulting in a very limited speed regulation capability of the motor system in the small electric power range, and conduction The loss is higher.

In order to expand the speed/power adjustment capability of the BLDCM, an embodiment of the present application provides a control method. First, obtain the target value of the parameter to be controlled of the BLDCM, where the parameters to be controlled include any of the following: the speed of the BLDCM, the speed of the BLDCM Power; that is, obtain the target speed of the BLDCM, or obtain the target power of the BLDCM, and use it as a target value to adjust the duty cycle of the DC-DC converter and the conduction length of the switching tube of the three-phase inverter. In this way, the rotation speed and power of the BLDCM can be adjusted within a wide range.

S102: Based on the target value, adjust the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter to obtain the target duty cycle of the DC-DC converter and the three-phase inverter. The target conduction length of the switching tube in the transformer;

After obtaining the target value, the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter can be adjusted based on the target value, where the current duty cycle of the DC-DC converter The air ratio and the current conduction length of the switching tube of the three-phase inverter are stored locally and can be obtained directly.

Among them, the current conduction length and the target conduction length are the conduction lengths relative to the electrical angle of the BLDCM; it can be seen that the state of the switching tube of the three-phase inverter is related to the electrical angle of the BLDCM and is driven at 120 degrees For BLDCM, when the rotor is a pair of magnetic poles, the electrical angle is equal to the mechanical angle, which is 360 degrees. In order to control the BLDCM, the maximum conduction length of the switching tube of the three-phase inverter is usually set to 120. That is to say, the maximum conduction length of the switching tube is 120 degrees at an electrical angle of 360 degrees, and the switching tube is closed at the remaining electrical angles; here, it should be noted that in order to control the BLDCM, usually a three-phase inverter The electrical angle range corresponding to the conduction length of each switch tube in the device is different.

Wherein, the above-mentioned current conduction length and target conduction length include the current conduction length of each switch tube and the target conduction length of each switch tube.

In this way, the target duty cycle and target conduction length can be obtained based on the target value.

S103: Control the DC-DC converter based on the target duty cycle, and control the three-phase inverter based on the target conduction length to drive the BLDCM.

After obtaining the target duty cycle and the target conduction length, the target duty cycle can be used to control the state of the switching tube in the DC-DC converter, so that the duty cycle of the DC-DC converter is the target duty cycle. , the target conduction length can be used to control the state of the switching tube in the three-phase inverter, so that the conduction length of the switching tube in the three-phase inverter is the target conduction length, thereby achieving control of the BLDCM speed or power. Control, so that the BLDCM speed is close to the target speed, or the BLDCM power is close to the target power.

For BLDCM startup, in order to adjust the BLDCM rotation speed or the BLDCM power, in an optional embodiment, the above method also includes:

Get the current voltage supplied by the DC-DC converter to the three-phase inverter;

Based on the preset mapping relationship, determine the target duty cycle of the DC-DC converter and the target conduction length of the switching tube in the three-phase inverter according to the target value and current voltage;

It can be understood that when the BLDCM is first started, a preset mapping relationship can be stored in advance for the duty cycle of the DC-DC converter and the conduction length of the switching tube in the three-phase inverter, where the preset The mapping relationship is from the parameters to be controlled and voltage to the duty cycle and conduction length. In this way, after obtaining the current voltage supplied by the DC-DC converter to the three-phase inverter, the target value and the current Voltage, find the corresponding duty cycle and conduction length from the preset mapping relationship, which is the target duty cycle of the DC-DC converter and the target conduction length of the switching tube in the three-phase inverter.

That is to say, after the BLDCM startup is completed, through the mapping relationship, the target value and the current voltage supplied by the DC-DC converter to the three-phase inverter can be obtained, and the target duty cycle of the DC-DC converter and the three-phase inverter can be obtained by mapping. The target conduction length of the switching tube in the converter is used to control the BLDCM based on the target duty cycle and target conduction length to make it close to the target value.

It should be noted that here, the lead angle of the BLDCM can also be adjusted to control the speed or power of the BLDCM. Therefore, the preset mapping relationship can also map the parameters to be controlled and the voltage to the duty cycle and conduction length. and lead angle. Using this mapping relationship, the target duty cycle, target conduction length and target lead angle can be obtained.

In addition, after the BLDCM completes startup, in addition to using the target value to obtain the target duty cycle and the target conduction length, in an optional embodiment, the above method also includes:

When the current voltage is less than the preset voltage threshold, return to execution based on the preset mapping relationship, and determine the target duty cycle of the DC-DC converter and the target of the switching tube in the three-phase inverter based on the target value and the current voltage. conduction length.

In practical applications, the current voltage will decrease with the use of BLDCM. In order to prevent the current voltage from decreasing, the control of BLDCM is more suitable for the actual use of BLDCM. Here, in the control of BLDCM, the change of the current voltage is detected, When the current voltage is less than the preset voltage threshold, return to the above-mentioned preset mapping relationship to re-determine the target duty cycle and target conduction length; for the situation where the current voltage is greater than or equal to the preset voltage threshold, the above S102 and S103 is used to control BLDCM to make it closer to the target value.

In order to achieve a larger range of rotation speed/power adjustment for BLDCM, in an optional embodiment, S102 may include:

Obtain the measured value of the BLDCM parameter to be controlled, and calculate the difference between the measured value and the target value;

When the difference is positive and greater than the preset threshold, based on the relationship between the current duty cycle of the DC-DC converter and the preset first duty cycle threshold, the current duty cycle of the DC-DC converter is calculated respectively. The ratio and the current conduction length of the switch tube of the three-phase inverter are adjusted to obtain the target duty cycle of the DC-DC converter and the target conduction length of the switch tube of the three-phase inverter;

When the difference is negative and the absolute value of the difference is greater than the preset threshold, based on the relationship between the current conduction length of the switching tube of the three-phase inverter and the preset conduction length threshold, the DC- The current duty cycle of the DC converter and the current conduction length of the switching tube of the three-phase inverter are adjusted to obtain the target duty cycle of the DC-DC converter and the target conduction length of the switching tube of the three-phase inverter. .

Understandably, the measured value of the parameter to be controlled by the BLDCM is first obtained, and after calculating the difference between the target value and the measured value, if the absolute value of the difference is less than the preset threshold, the DC-DC converter will not be used. The current duty cycle and the target conduction length of the switching tube in the three-phase inverter can be adjusted, and the original parameters can be maintained.

If the absolute value of the difference is greater than the preset threshold and the difference is positive, in order to adjust the duty cycle and conduction length, here, based on the current duty cycle of the DC-DC converter and the preset The relationship between the first duty cycle threshold is used to adjust the current duty cycle and the current conduction length to obtain the target duty cycle and the target conduction length. Here, the preset first duty cycle threshold is less than the preset Set the second duty cycle threshold.

If the absolute value of the difference is less than the preset threshold and the difference is negative, in order to adjust the duty cycle and conduction length, here, based on the current conduction length of the switching tube in the three-phase inverter and the preset The relationship between the set conduction length thresholds is used to adjust the current duty cycle and the current conduction length to obtain the target duty cycle and target conduction length. Here, the preset conduction length threshold can be The maximum value of the length, for example, for a BLDCM driven at 120 degrees, the preset conduction length threshold is 120 degrees.

For the situation where the absolute value of the difference is equal to the preset threshold, the original duty cycle and the original conduction length can be maintained, or they can be classified according to the positive and negative values of the difference. When the difference is positive, Based on the relationship between the current duty cycle of the DC-DC converter and the preset first duty cycle threshold, the current duty cycle and the current conduction length are adjusted to obtain the target duty cycle and target conduction Length, for negative difference values, based on three phases The relationship between the current conduction length of the switching tube in the inverter and the preset conduction length threshold is used to adjust the current duty cycle and current conduction length to obtain the target duty cycle and target conduction length. In this way, the duty cycle and the conduction length are adjusted. Currently, the current duty cycle and the current conduction length can also be adjusted in other ways. Here, the embodiments of the present application do not specifically limit this.

In order to obtain the target duty cycle and the target conduction length based on the relationship between the current duty cycle and the preset first duty cycle threshold, in an optional embodiment, based on the current duty cycle of the DC-DC converter, The relationship between the duty cycle and the preset first duty cycle threshold is adjusted respectively to the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter to obtain the DC-DC The target duty cycle of the converter and the target conduction length of the switching tube of the three-phase inverter include:

When the current duty cycle of the DC-DC converter is less than the preset first duty cycle threshold, the difference between the current duty cycle of the DC-DC converter and the preset duty cycle step is determined as DC- The target duty cycle of the DC converter;

When the current duty cycle of the DC-DC converter is greater than the preset first duty cycle threshold, the difference between the current conduction length of the switching tube of the three-phase inverter and the preset conduction length step is determined. is the target conduction length of the switching tube of the three-phase inverter.

Here, first determine the size between the current duty cycle and the preset first duty cycle threshold. When the current duty cycle is less than the preset first duty cycle threshold, the current duty cycle needs to be reduced to reduce power. , where the target duty cycle can be obtained by reducing the current duty cycle by a preset duty cycle step. Of course, other methods can also be used to reduce the current duty cycle to obtain the target duty cycle. Here, this The application examples do not specifically limit this.

Through judgment, when the current duty cycle is greater than the preset first duty cycle threshold, it is necessary to reduce the current conduction length to reduce power, wherein the current conduction length can be reduced by a preset conduction length step. To obtain the target conduction length, of course, other methods can be used to reduce the current conduction length to obtain the target conduction length. Here, the embodiments of the present application do not specifically limit this.

In addition, for the situation where the current duty cycle is equal to the preset first duty cycle threshold, the situation where the current duty cycle is less than the preset first duty cycle threshold can be used, or the current duty cycle can be used The situation is handled when it is greater than the preset first duty cycle threshold. Here, the embodiment of the present application does not specifically limit this.

Furthermore, in order to expand the speed/power adjustment range, the lead angle of the BLDCM can also be adjusted. In an optional embodiment, when the current duty cycle of the DC-DC converter is less than the preset duty cycle When the threshold is reached, the difference between the current duty cycle of the DC-DC converter and the preset duty cycle step is determined as the target duty cycle of the DC-DC converter, including:

When the current lead angle of the BLDCM is greater than the preset angle threshold, the difference between the current lead angle of the BLDCM and the preset lead angle step is determined as the target lead angle of the BLDCM;

When the current lead angle of the BLDCM is less than the preset angle threshold and the current duty cycle of the DC-DC converter is less than the preset first duty cycle threshold, compare the current duty cycle of the DC-DC converter with the preset The difference between the duty cycle steps is determined as the target duty cycle of the DC-DC converter.

In the process of adjusting the current duty cycle and current conduction length, first determine the relationship between the current lead angle of BLDC and the preset angle threshold. After judgment, when the current lead angle of BLDCM is greater than the preset angle When the threshold is reached, the current lead angle needs to be reduced to reduce power. Here, the target lead angle is obtained by reducing the current lead angle by a preset lead angle step.

If it is judged that when the current lead angle of BLDCM is less than the preset angle threshold, it is necessary to further determine the relationship between the current duty cycle and the preset first duty cycle threshold time. If it is less than the preset first duty cycle threshold time, the current duty cycle needs to be reduced. Here, the target duty cycle is obtained by reducing the current duty cycle by a preset duty cycle step.

For the situation where the current lead angle is equal to the preset angle threshold, the above situation of greater than or below can be used to handle the situation. Here, the embodiment of the present application does not specifically limit this.

In adjusting the lead angle of the BLDCM, in an optional embodiment, when the current duty cycle of the DC-DC converter is greater than the preset first duty cycle threshold, the three-phase inverter is The difference between the current conduction length of the switch tube and the preset conduction length step is determined as the target conduction length of the switch tube of the three-phase inverter, including:

When the current lead angle of the BLDCM is less than the preset angle threshold and the current duty cycle of the DC-DC converter is greater than the preset first duty cycle threshold, the current conduction length of the switching tube of the three-phase inverter is The difference from the preset conduction length step is determined as the target conduction length of the switching tube of the three-phase inverter.

It can be understood that when the current lead angle is less than the preset angle threshold and the current duty cycle is greater than the preset first duty cycle threshold, the current conduction length needs to be smaller to reduce the power. Here, the current conduction length is The conduction length is reduced by a preset conduction length step to obtain the target conduction length. Of course, other methods can also be used to reduce the current conduction length. Here, the embodiments of the present application do not specifically limit this.

In addition, for the situation where the current duty cycle is equal to the preset first duty cycle threshold, it can be processed with reference to the situation of less than, or with reference to the situation of greater. Here, the embodiment of the present application does not specifically limit this.

In the adjustment of the current duty cycle and the current conduction length, in an optional embodiment, based on the current conduction length of the switching tube of the three-phase inverter and the preset conduction length threshold Relationship, respectively adjust the current duty cycle of the DC-DC converter and the current conduction length of the switch tube of the three-phase inverter to obtain the target duty cycle of the DC-DC converter or the switch of the three-phase inverter. The target conductive length of the tube, including:

When the current conduction length of the switch tube of the three-phase inverter is less than the preset conduction length threshold, the sum of the current conduction length and the preset conduction length step is determined as the switch of the three-phase inverter. The target conduction length of the tube;

When the current conduction length of the switching tube of the three-phase inverter is equal to the preset conduction length threshold, and the current duty cycle of the DC-DC converter is less than the preset second duty cycle threshold, the DC-DC The sum of the current duty cycle of the converter and the preset duty cycle step is determined as the target duty cycle of the DC-DC converter.

Understandably, the relationship between the current conduction length and the preset conduction length threshold is first determined. When the current conduction length is less than the preset conduction length threshold, the current conduction length needs to be increased to increase power. , so the current conduction length is added to the preset conduction length step to obtain the target conduction length. Of course, other methods can also be used to increase the current conduction length. Here, the embodiment of the present application does not elaborate on this. limited.

When the current conduction length is equal to the preset conduction length threshold, it is necessary to further determine the relationship between the current duty cycle and the preset second duty cycle. When the current duty cycle is less than the preset second duty cycle When the ratio is higher than the threshold, increase the current duty cycle to increase power. You can add the current duty cycle to the preset duty cycle step. Thus, the target duty cycle is obtained. Of course, other methods can also be used to increase the current duty cycle. Here, the embodiments of the present application do not specifically limit this.

Further, in order to expand the speed/power adjustment range, the current lead angle of the BLDCM can be adjusted. In an optional embodiment, when the current conduction length of the switching tube of the three-phase inverter is equal to the preset conduction length threshold, and the current duty cycle of the DC-DC converter is less than the preset second duty cycle threshold, the current duty cycle of the DC-DC converter is divided into the preset duty cycle step length. and, determined as the target duty cycle of the DC-DC converter, including:

When the current conduction length of the switch tube of the three-phase inverter is equal to the preset conduction length threshold, and the current duty cycle of the DC-DC converter is equal to the preset second duty cycle threshold, the current conduction length of the BLDCM is equal to the preset second duty cycle threshold. The sum of the lead angle and the preset lead angle step is determined as the target lead angle of BLDCM;

That is to say, when the current conduction length is equal to the preset conduction length threshold and the current duty cycle is equal to the preset second duty cycle threshold, the current lead angle needs to be increased to increase the power. You can use the current The lead angle is added to the preset lead angle step to obtain the target lead angle of BLDCM. Of course, other methods can be used to increase the current lead angle. Here, the embodiment of the present application does not specifically limit this.

When the current conduction length is equal to the preset conduction length threshold and the current duty cycle is less than the preset second duty cycle threshold, the current duty cycle needs to be increased. You can add the current duty cycle to the preset The duty cycle step size is used to obtain the target duty cycle to increase the power. Of course, other methods can also be used to increase the current duty cycle. Here, the embodiments of the present application do not specifically limit this.

The following examples are used to illustrate the control method described in one or more of the above embodiments.

Figure 2 is a schematic diagram of an optional BLDCM control provided by the embodiment of the present application. As shown in Figure 2, the BLDCM hardware drive circuit includes: battery, DC-DC converter (also called a buck circuit) and three-phase inverter. In this example, the control parameter table and speed/power closed-loop control system are used to control the drive circuit to control the BLDCM.

Among them, the closed-loop control system includes a current and voltage measurement module for input power calculation and a rotor position detection module for motor speed estimation.

In Figure 2, the main software module "control parameter table and speed/power closed-loop control system" receives and processes information such as target power (or target speed), measured voltage, measured power, measured speed, and rotor position. Generate parameters such as the duty cycle parameters of the DC-DC converter (equivalent to the above target duty cycle), the conduction time of the inverter bridge (equivalent to the above target conduction length) and the lead angle (equivalent to the above target lead angle). , and ultimately achieve the purpose of controlling the motor power (or speed).

Based on the structure and control strategy of Figure 2 above, Figure 3a is a schematic flowchart of Example 1 of an optional control method provided by the embodiment of the present application. As shown in Figure 3a, the control method may include:

S3a01: Boot acceleration;

S3a02: The startup process is completed;

S3a03: Obtain the target power value;

S3a04: Use the control parameter table to set initial control parameters;

S3a05: Enter the control parameter setting cycle of the next control cycle; when there is a new target power command, return to S3a03;

S3a06: After obtaining the shutdown command, shut down and slow down.

Based on the structure and control strategy of Figure 2 above, Figure 3b is a schematic flow chart of Example 2 of an optional control method provided by the embodiment of the present application. As shown in Figure 3b,

S3b01: Boot acceleration;

S3b02: The startup process is completed;

S3b03: Get the target speed value;

S3b04: Use the control parameter table to set initial control parameters;

S3b05: Enter the control parameter setting cycle of the next control cycle; when there is a new target speed command, return to S3b03;

S3b06: After receiving the shutdown command, shut down and slow down.

That is to say, BLDCM accelerates after starting up. After the startup process is completed, the target power value or target speed value is obtained, and the initial control parameters are set using the control parameter table. That is, the target power value and the current voltage are used to query the control parameter table. Obtain the duty cycle, conduction length and lead angle by using the table, or use the target speed value and current voltage to obtain the duty cycle, conduction length and lead angle from the control parameter table by looking up the table, before entering the next control The cycle uses the obtained duty cycle, conduction length and lead angle to control the hardware driver circuit. When a new target power value or a new target speed value is received, the settings of the duty cycle, conduction length and lead angle are executed upon return. .

It should be noted that Figure 3a and Figure 3b show two startup/operation/shutdown processes based on power control and speed control respectively. After the initial startup process is completed or the system receives a new target power/target speed command, the system The control parameter table will be used to look up the initial control parameters to quickly approach the target power/speed, and then the system will enter the control parameter setting process for the next control cycle.

Wherein, the above-mentioned control period is a period including at least one electrical angle or more than one electrical angle.

Based on the above Figure 3a, Figure 4a is a schematic flow chart of Example 1 of an optional control parameter provided by the embodiment of the present application. As shown in Figure 4a, the output item of the control parameter table is the duty cycle of the DC-DC converter. , the conduction length of the switching tube of the three-phase inverter (can be marked as a percentage), and the leading angle of BLDCM. In the power control mode, the input items of the control parameter table are the target power and the current voltage, and the current voltage is the DC-DC converter output voltage (the input voltage of the three-phase inverter).

Based on the above-mentioned Figure 3b, Figure 4b is a flow diagram of Example 2 of an optional control parameter provided by the embodiment of the present application. As shown in Figure 4b, the output item of the control parameter table is the duty cycle of the DC-DC converter. , the conduction length of the switching tube of the three-phase inverter, and the lead angle of the three-phase inverter. In the speed control mode, the input items of the control parameter table are the target speed and the current voltage, Figure 4(b).

After the control parameters of the current control period are set, the system enters the control parameter setting process of the next control period. Figure 5a is a flow diagram of Example 3 of an optional control method provided by the embodiment of the present application, as shown in Figure 5a As shown, the control method may include:

S5a01: Start setting the control parameters of the next control cycle;

S5a02: Obtain the Hall signal and update the speed information based on the latest acquired signal;

S5a03: Obtain the target power and the measured power, and calculate the power difference (measured power from - target power);

S5a04: Determine whether the power difference is greater than the preset threshold? If yes, execute S5a05; if no, execute S5a06;

S5a05: Determine whether the power difference is positive? If yes, execute S5a07; if no, execute S5a08;

S5a06: The next control cycle uses the same control parameters as this control cycle and executes S5a17.

S5a07: Determine whether the lead angle is the minimum value of the lead angle? If yes, execute S5a09; if no, execute S5a11;

S5a08: Determine whether the conduction length reaches 120 degrees? If yes, execute S5a10; if no, execute S5a16;

S5a09: Determine whether the duty cycle reaches the lower limit of the duty cycle? If yes, execute S5a13; if no, execute S5a12;

S5a10: Determine whether the duty cycle reaches the upper limit of the duty cycle? If yes, execute S5a14; if no, execute S5a15;

S5a11: In the next control cycle, the lead angle decreases by a preset lead angle step, and S5a17 is executed.

S5a12: In the next control cycle, the duty cycle decreases by a preset duty cycle step, and S5a17 is executed.

S5a13: In the next control cycle, the conduction length decreases by a preset conduction length step, and S5a17 is executed.

S5a14: In the next control cycle, the lead angle increases by a preset lead angle step, and S5a17 is executed.

S5a15: In the next control cycle, the duty cycle increases by a preset duty cycle step, and S5a17 is executed.

S5a16: In the next control cycle, the conduction length increases by a preset conduction length step, and S5a17 is executed.

S5a17: End the setting of control parameters.

Figure 5b is a schematic flowchart of Example 4 of an optional control method provided by the embodiment of the present application. As shown in Figure 5b,

S5b01: Start setting the control parameters of the next control cycle;

S5b02: Obtain the Hall signal and update the speed information based on the latest acquired signal;

S5b03: Obtain the current target speed and measured speed of the motor, and calculate the power difference (measured speed from - target speed);

S5b04: Determine whether the speed difference is greater than the preset threshold? If yes, execute S5b05; if no, execute S5b06;

S5b05: Determine whether the speed difference is positive? If yes, execute S5b07; if no, execute S5b08;

S5b06: The next control cycle uses the same control parameters as this control cycle and executes S5b17.

S5b07: Determine whether the lead angle is the minimum value of the lead angle? If yes, execute S5b09; if no, execute S5b11;

S5b08: Determine whether the conduction length reaches 120 degrees? If yes, execute S5b10; if no, execute S5b16;

S5b09: Determine whether the duty cycle reaches the lower limit of the duty cycle? If yes, execute S5b13; if no, execute S5b12;

S5b10: Determine whether the duty cycle reaches the upper limit of the duty cycle? If yes, execute S5b14; if no, execute S5b15;

S5b11: In the next control cycle, the lead angle decreases by a preset lead angle step, and S5b17 is executed.

S5b12: In the next control cycle, the duty cycle decreases by a preset duty cycle step, and S5b17 is executed.

S5b13: In the next control cycle, the conduction length decreases by a preset conduction length step, and S5b17 is executed.

S5b14: In the next control cycle, the lead angle increases by a preset lead angle step, and S5b17 is executed.

S5b15: In the next control cycle, the duty cycle increases by a preset duty cycle step, and S5b17 is executed.

S5b16: In the next control cycle, the conduction length increases by a preset conduction length step, and S5b17 is executed.

S5b17: End the setting of control parameters.

As can be seen from Figure 5a and Figure 5b above, in order to reduce system disturbance, when the difference between the target power or target speed and the actual measured power or measured speed is less than the set threshold, the control parameters of the next control cycle will inherit the current control parameters, and End the control parameter setting process.

When the system determines that the difference in power or speed is positive and exceeds the threshold, if the current BLDCM lead angle does not reach the preset minimum lead angle, the system will reduce the lead angle step by one in the next control cycle and end the control. Parameter setting process; otherwise, if the current BLDCM lead angle has reached the preset minimum value of the lead angle, the system will continue to determine whether the current duty cycle of the DC-DC converter has reached the preset lower limit of the duty cycle. , if yes, reduce a preset duty cycle step in the next control cycle and end the control parameter setting process; otherwise, reduce a preset conduction length step in the next control cycle and end Control the parameter setting process.

When the system determines that the difference in power or speed is negative and exceeds the preset threshold, if the current BLDCM conduction length does not reach the preset maximum conduction length (120 degrees electrical angle in 120-degree BLDCM control), The system will add a preset conduction length step in the next control cycle and end the control parameter setting process; otherwise, if the current BLDCM conduction length has reached the preset maximum conduction length, the system will continue to determine Whether the current duty cycle of the DC-DC converter reaches the preset upper limit of the duty cycle, if so, add a preset lead angle step in the next control cycle and end the control parameter setting process; Otherwise, a preset duty cycle step is added in the next control cycle and the control parameter setting process ends.

Figure 6 is a schematic diagram of the control parameters of an optional BLDCM provided by the embodiment of the present application. As shown in Figure 6, switch tube S1, switch tube S2, switch tube S3, switch tube S4, switch tube S5 and switch tube S6 in 360 The conduction length in an electrical angle of degrees. When the BLDCM lead angle and conduction length parameters of the next control cycle are determined, the system will estimate the back electromotive force in the next control cycle based on the speed and rotor position signals of this control cycle. The zero-crossing point position, and the control parameters set in advance turn on the corresponding switch tube in the inverter bridge in advance, and the conduction length of each switch tube is less than or equal to 120 degrees of electrical angle.

Figure 7 is a waveform diagram of the phase current of an optional BLDCM provided by the embodiment of the present application. As shown in Figure 7, the dotted line is the minimum current waveform in the traditional PAM solution, and the solid line is the minimum current waveform after adjusting the conduction length. From the waveform diagram, it can be seen that the conduction length of the switching tube of the three-phase inverter is adjustable. Compared with traditional PAM control, this can further reduce the effective value of the phase current after the output voltage of the DC-DC converter is minimum. The purpose of extending the lower limit of the debugging range is achieved, and this beneficial effect will not lead to an increase in system costs or a decrease in efficiency.

It should be noted that the above adjustment and control of the control parameters can be achieved by using a proportional integral (Proportional Integral, PI) controller.

The control method provided by the embodiment of the present application is used to control BLDCM. The hardware driver circuit of BLDCM includes: DC-DC converter and three-phase inverter, including: obtaining the target value of the parameter to be controlled by BLDCM, Based on the target value, the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter are adjusted respectively to obtain the target duty cycle of the DC-DC converter and the three-phase inverter. The target conduction length of the middle switch tube; where the current conduction length and the target conduction length are the conduction lengths relative to the electrical angle of the BLDCM, the DC-DC converter is controlled based on the target duty cycle, and the DC-DC converter is controlled based on the target conduction length. A three-phase inverter to drive the BLDCM; that is to say, in the embodiment of the present application, the current duty cycle of the DC-DC converter and the three-phase inverter are respectively adjusted based on the obtained target values of the parameters to be controlled. By adjusting the current conduction length of the switching tube of the inverter, the target duty cycle of the DC-DC converter and the target conduction length of the switching tube in the three-phase inverter can be obtained, and based on this, the BLDCM is controlled so that the BLDCM The parameters to be controlled are getting closer and closer to the target value. Here, the target value is used not only to adjust the duty cycle of the DC-DC converter, but also to adjust the conduction length of the switching tube of the three-phase inverter. In this way, After the output voltage of the DC-DC converter is minimum, the effective value of the phase current of the BLDCM can be further reduced, thereby achieving the purpose of expanding the power/speed adjustment range, that is, increasing the power/speed adjustment range of the BLDCM.

Based on the same inventive concept, embodiments of the present application provide a control device. Figure 8 is a schematic structural diagram of an optional control device provided by the embodiment of the present application. Refer to Figure 8 and include: an acquisition module 81 and an adjustment module. 82 and control module 83; where,

Obtaining module 81 is used to obtain the target value of the parameter to be controlled by BLDCM;

The adjustment module 82 is used to respectively adjust the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter based on the target value to obtain the target duty cycle of the DC-DC converter. and the target conduction length of the switching tube in the three-phase inverter; where the current conduction length and the target conduction length are the conduction lengths relative to the electrical angle of the BLDCM;

The control module 83 is used to control the DC-DC converter based on the target duty cycle and the three-phase inverter based on the target conduction length to drive the BLDCM.

In other embodiments of this application, the parameters to be controlled include any of the following:

The speed of BLDCM, the power of BLDCM.

In other embodiments of this application, the above control device is also used for:

Among them, the preset mapping relationship is the mapping relationship from the parameter to be controlled and the voltage to the duty cycle and the conduction length.

When the current voltage is less than the preset voltage threshold, return to the preset mapping relationship to determine the target duty cycle of the DC-DC converter and the target conduction of the switching tube in the three-phase inverter based on the target value and the current voltage. pass length.

In other embodiments of this application, the adjustment module 82 is specifically used for:

In other embodiments of the present application, the adjustment module 82 adjusts the current duty cycle of the DC-DC converter and the three preset duty cycle thresholds based on the relationship between the current duty cycle of the DC-DC converter and the preset first duty cycle threshold. The current conduction length of the switching tube of the three-phase inverter is adjusted to obtain the target duty cycle of the DC-DC converter and the target conduction length of the switching tube of the three-phase inverter, including:

In other embodiments of the present application, when the current duty cycle of the DC-DC converter is less than the preset duty cycle threshold, the adjustment module 82 sets the current duty cycle of the DC-DC converter to the preset duty cycle step. The long difference, determined as the target duty cycle of the DC-DC converter, includes:

When the current lead angle of the BLDCM is less than the preset angle threshold and the current duty of the DC-DC converter When the ratio is less than the preset first duty cycle threshold, the difference between the current duty cycle of the DC-DC converter and the preset duty cycle step is determined as the target duty cycle of the DC-DC converter.

In other embodiments of the present application, when the current duty cycle of the DC-DC converter is greater than the preset first duty cycle threshold, the adjustment module 82 changes the current conduction length of the switch tube of the three-phase inverter to the preset The difference between the step lengths is determined as the target conduction length of the switching tube of the three-phase inverter, including:

In other embodiments of the present application, the adjustment module 82 adjusts the current duty cycle and the preset conduction length threshold of the DC-DC converter based on the relationship between the current conduction length of the switching tube of the three-phase inverter and the preset conduction length threshold. The current conduction length of the switch tube of the three-phase inverter is adjusted to obtain the target duty cycle of the DC-DC converter or the target conduction length of the switch tube of the three-phase inverter, including:

In other embodiments of the present application, the adjustment module 82 adjusts when the current conduction length of the switch tube of the three-phase inverter is equal to the preset conduction length threshold, and the current duty cycle of the DC-DC converter is less than the preset second When the duty cycle threshold is set, the sum of the current duty cycle of the DC-DC converter and the preset duty cycle step is determined as the target duty cycle of the DC-DC converter, including:

In practical applications, the above-mentioned acquisition module 81, adjustment module 82 and control module 83 can be implemented by a processor located on the control device, specifically a central processing unit (CPU, Central Processing Unit), a microprocessor (MPU, Microprocessor Unit), Digital signal processor (DSP, Digital Signal Processing) or field programmable gate array (FPGA, Field Programmable Gate Array) and other implementations.

Figure 9 is a schematic structural diagram of an optional control device provided by an embodiment of the present application. As shown in Figure 9, an embodiment of the present application provides a control device 900, which includes:

The processor 91 and the storage medium 92 that stores instructions executable by the processor 91. The storage medium 92 relies on the processor 91 to perform operations through the communication bus 93. When the instructions are executed by the processor 91, Execute the control method described in one or more of the above embodiments.

It should be noted that in actual application, various components in the terminal are coupled together through the communication bus 93 . It can be understood that the communication bus 93 is used to implement connection communication between these components. In addition to the data bus, the communication bus 93 also includes a power bus, a control bus and a status signal bus. However, for the sake of clarity, the various buses are labeled as communication bus 93 in FIG. 9 .

Embodiments of the present application provide a storage medium that stores one or more programs, and the one or more programs can be executed by one or more processors according to the control method provided by the embodiments of the present application.

Those skilled in the art will understand that embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, magnetic disk storage and optical storage, etc.) embodying computer-usable program code therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each process and/or block in the flowchart illustrations and/or block diagrams, and combinations of processes and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce a use A device for realizing the functions specified in one process or multiple processes of the flowchart and/or one block or multiple blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory that causes a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction means, the instructions The device implements the functions specified in a process or processes of the flowchart and/or a block or blocks of the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device, causing a series of operating steps to be performed on the computer or other programmable device to produce computer-implemented processing, thereby executing on the computer or other programmable device. Instructions provide steps for implementing the functions specified in a process or processes of a flowchart diagram and/or a block or blocks of a block diagram.

The above descriptions are only preferred embodiments of the present application and are not intended to limit the scope of protection of the present application.

Industrial applicability

The control method, device and storage medium provided by the embodiment of the present application are used to control BLDCM. The hardware driver circuit of BLDCM includes: DC-DC converter and three-phase inverter, including: obtaining the BLDCM to be controlled Based on the target value of the parameter, the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter are adjusted respectively to obtain the target duty cycle and The target conduction length of the switching tube in the three-phase inverter; where the current conduction length and the target conduction length are the conduction lengths relative to the electrical angle of the BLDCM, and the DC-DC converter is controlled based on the target duty cycle, based on The target conduction length controls the three-phase inverter to drive the BLDCM; that is to say, in the embodiment of this application, through Based on the obtained target values of the parameters to be controlled, the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter are adjusted respectively, so that the target of the DC-DC converter can be obtained The duty cycle and the target conduction length of the switching tube in the three-phase inverter are used to control the BLDCM, so that the controlled parameters of the BLDCM are getting closer and closer to the target value. Here, the target value is used not only to control the DC-DC The duty cycle of the converter is adjusted, and the conduction length of the switching tube of the three-phase inverter is also adjusted. In this way, the effective phase current of the BLDCM can be further reduced after the output voltage of the DC-DC converter is minimum. value, thereby achieving the purpose of expanding the power/speed adjustment range, that is, improving the power/speed adjustment range of the BLDCM.

Claims

A control method, the method is used to control a brushless DC motor, the hardware drive circuit of the brushless DC motor includes: a DC-DC converter and a three-phase inverter, including:

Obtain the target value of the parameter to be controlled of the brushless DC motor;

Based on the target value, the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter are respectively adjusted to obtain the target duty cycle of the DC-DC converter. The air ratio and the target conduction length of the switching tube in the three-phase inverter; wherein the current conduction length and the target conduction length are the conduction lengths relative to the electrical angle of the brushless DC motor. ;

The DC-DC converter is controlled based on the target duty cycle, and the three-phase inverter is controlled based on the target conduction length to drive the brushless DC motor.
The method according to claim 1, wherein the parameters to be controlled include any of the following:

The rotation speed of the brushless DC motor and the power of the brushless DC motor.
The method of claim 1, further comprising:

Obtain the current voltage supplied by the DC-DC converter to the three-phase inverter;

Based on the preset mapping relationship, determine the target duty cycle of the DC-DC converter and the target conduction length of the switching tube in the three-phase inverter according to the target value and the current voltage;

Wherein, the preset mapping relationship is a mapping relationship from parameters to be controlled and voltage to duty cycle and conduction length.
The method of claim 3, further comprising:

When the current voltage is less than the preset voltage threshold, return to the preset-based mapping relationship, and determine the target duty cycle and the target duty cycle of the DC-DC converter based on the target value and the current voltage. Describe the target conduction length of the switching tube in the three-phase inverter.
The method according to claim 1, wherein based on the target value, the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter are respectively determined. Adjust to obtain the target duty cycle of the DC-DC converter and the target conduction length of the switching tube in the three-phase inverter, including:

Obtain the measured value of the parameter to be controlled of the brushless DC motor, and calculate the difference between the measured value and the target value;

When the difference is positive and greater than the preset threshold, based on the relationship between the current duty cycle of the DC-DC converter and the preset first duty cycle threshold, the DC-DC converter is The current duty cycle of the converter and the current conduction length of the switching tube of the three-phase inverter are adjusted to obtain the target duty cycle of the DC-DC converter and the switching tube of the three-phase inverter. The target conduction length;

When the difference is a negative value and the absolute value of the difference is greater than the preset threshold, based on the current conduction length of the switching tube of the three-phase inverter and the preset conduction length threshold relationship, respectively adjust the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter to obtain the target duty cycle of the DC-DC converter and the required Describe the target conduction length of the switching tube of the three-phase inverter.
The method according to claim 5, wherein the current occupation based on the DC-DC converter The relationship between the duty cycle and the preset first duty cycle threshold is to adjust the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter respectively, Obtain the target duty cycle of the DC-DC converter and the target conduction length of the switching tube of the three-phase inverter, including:

When the current duty cycle of the DC-DC converter is less than the preset first duty cycle threshold, the difference between the current duty cycle of the DC-DC converter and the preset duty cycle step is, Determine the target duty cycle of the DC-DC converter;

When the current duty cycle of the DC-DC converter is greater than the preset first duty cycle threshold, the current conduction length of the switch tube of the three-phase inverter is compared with the preset conduction length step The difference is determined as the target conduction length of the switching tube of the three-phase inverter.
The method of claim 6, wherein when the current duty cycle of the DC-DC converter is less than a preset duty cycle threshold, comparing the current duty cycle of the DC-DC converter with The difference between the preset duty cycle steps is determined as the target duty cycle of the DC-DC converter, including:

When the current lead angle of the brushless DC motor is greater than the preset angle threshold, the difference between the current lead angle of the brushless DC motor and the preset lead angle step is determined as the Target lead angle;

When the current lead angle of the brushless DC motor is less than the preset angle threshold, and the current duty cycle of the DC-DC converter is less than the preset first duty cycle threshold, the DC-DC converter The difference between the current duty cycle of the converter and the preset duty cycle step is determined as the target duty cycle of the DC-DC converter.
The method according to claim 7, wherein when the current duty cycle of the DC-DC converter is greater than a preset first duty cycle threshold, the switch tube of the three-phase inverter is turned on. The difference between the current conduction length and the preset conduction length step is determined as the target conduction length of the switching tube of the three-phase inverter, including:

When the current lead angle of the brushless DC motor is less than the preset angle threshold and the current duty cycle of the DC-DC converter is greater than the preset first duty cycle threshold, the three-phase inverter is The difference between the current conduction length of the switch tube of the inverter and the preset conduction length step is determined as the target conduction length of the switch tube of the three-phase inverter.
The method according to claim 5, wherein the DC-DC conversion is performed respectively based on the relationship between the current conduction length of the switching tube of the three-phase inverter and a preset conduction length threshold. The current duty cycle of the converter and the current conduction length of the switching tube of the three-phase inverter are adjusted to obtain the target duty cycle of the DC-DC converter or the switching tube of the three-phase inverter. Target conduction length, including:

When the current conduction length of the switching tube of the three-phase inverter is less than the preset conduction length threshold, the sum of the current conduction length and the preset conduction length step is determined as the three-phase conduction length. The target conduction length of the switching tube of the phase inverter;

When the current conduction length of the switching tube of the three-phase inverter is equal to the preset conduction length threshold, and the current duty cycle of the DC-DC converter is less than the preset second duty cycle threshold, The sum of the current duty cycle of the DC-DC converter and the preset duty cycle step is determined as the target duty cycle of the DC-DC converter.
The method according to claim 9, wherein when the current conduction length of the switching tube of the three-phase inverter is equal to a preset conduction length threshold, and the current duty of the DC-DC converter Ratio is less than default When the second duty cycle threshold is reached, the sum of the current duty cycle of the DC-DC converter and the preset duty cycle step is determined as the target duty cycle of the DC-DC converter, including :

When the current conduction length of the switching tube of the three-phase inverter is equal to the preset conduction length threshold, and the current duty cycle of the DC-DC converter is equal to the preset second duty cycle threshold, The sum of the current lead angle of the brushless DC motor and the preset lead angle step is determined as the target lead angle of the brushless DC motor;

When the current conduction length of the switching tube of the three-phase inverter is equal to the preset conduction length threshold, and the current duty cycle of the DC-DC converter is less than the preset second duty cycle threshold, The sum of the current duty cycle of the DC-DC converter and the preset duty cycle step is determined as the target duty cycle of the DC-DC converter.
A control device used to control a brushless DC motor. The hardware drive circuit of the brushless DC motor includes: a DC-DC converter and a three-phase inverter, including:

An acquisition module, used to acquire target values of parameters to be controlled of the brushless DC motor;

an adjustment module, configured to respectively adjust the current duty cycle of the DC-DC converter and the current conduction length of the switching tube of the three-phase inverter based on the target value to obtain the DC-DC The target duty cycle of the converter and the target conduction length of the switching tube in the three-phase inverter; wherein the current conduction length and the target conduction length are relative to the electrical current of the brushless DC motor. Angle conduction length;

A control module configured to control the DC-DC converter based on the target duty cycle, and control the three-phase inverter based on the target conduction length to drive the brushless DC motor.
A control device including:

A processor and a storage medium storing instructions executable by the processor. The storage medium relies on the processor to perform operations through a communication bus. When the instructions are executed by the processor, the above-mentioned claims 1 to 1 are executed. The control method described in any one of 10.
A storage medium that stores one or more programs that can be executed by one or more processors to implement the control as described in any one of claims 1 to 10 method.