A control method and control device for an EPS system

Abstract

The application relates to the technical field of motor control, and discloses a control method and a control device of an EPS system, the method comprising the following steps: after receiving a driving instruction sent by an upper computer, sampling the current of a motor, sending the sampled current to a code subdivision processing module after processing the sampled current by a DSP; collecting an electric angle of the motor operation fed back by an encoder, and sending the collected electric angle value to the code subdivision processing module, wherein the angle rotated by the motor in one rotation is divided into six sectors; the code subdivision processing module determines the area where the electric angle is located, and determines the position of the motor according to the processing result of the sampled current by the DSP. The whole 360-degree rotation period is divided into six sectors, and the accurate position information is updated once every 60 degrees, so that the accuracy of the position information of the motor in the rotation process is improved, and the control effect of the power-assisted steering part of the whole vehicle is improved.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a control method and control device for an EPS system. Background Technology

[0002] Electric power steering (EPS) represents the future direction of automotive steering systems. This system eliminates the need for the power steering pump, hoses, hydraulic fluid, drive belt, and engine-mounted pulley required by hydraulic power steering systems, thus saving energy and protecting the environment. Furthermore, it features simple adjustment, flexible assembly, and the ability to provide steering assistance in various conditions. These advantages have led to EPS as a promising new steering technology.

[0003] EPS systems generally consist of a mechanical steering system plus a torque sensor, vehicle speed sensor, electronic control unit, reducer, and electric motor. Based on the traditional mechanical steering system, it uses an electronic control device to generate auxiliary power of corresponding magnitude and direction from the electric motor according to the torque signal on the steering wheel and the vehicle speed signal, to assist the driver in steering operations.

[0004] Currently, the mainstream EPS motor control system integrates the vehicle controller and motor driver into a single unit, lacking a separate drive unit for the steering motor. Existing technology for EPS servo motors uses encoder feedback units with switch Hall effect sensors, typically consisting of five switch Hall effect sensors spaced at a certain angle at the motor's tail. The output signal format is generally ABUVW level signals. The states of AB indicate the motor's rotation direction, while UVW indicates position information. Current technology processes the position signal by determining the motor's magnetic pole position based on the state of the first UVW signal, then estimating position and speed information based on the number of pulses fed back from the encoder. However, this estimation method cannot accurately determine the motor's position during rotation.

[0005] In view of this, it is necessary to propose a new control method for EPS systems. Summary of the Invention

[0006] The main objective of this invention is to provide a control method, device, and terminal equipment for an EPS system to solve the problem of inaccurate position information determination during motor rotation in the prior art.

[0007] To achieve the above objectives, a first aspect of the present invention provides a control method for an EPS system, the control method comprising:

[0008] After receiving the drive command sent by the host computer, the motor current is sampled, and the sampled current is processed by the DSP and then sent to the encoding subdivision processing module.

[0009] The electrical angle of the motor rotation fed back by the encoder is collected and the collected electrical angle value is sent to the encoding subdivision processing module. The angle of rotation of the motor in one revolution is divided into 6 sectors.

[0010] The encoding subdivision processing module determines the region where the electrical angle is located, and determines the position of the motor based on the processing result of the sampled current obtained by the DSP.

[0011] Optionally, the drive commands sent by the host computer include position commands, speed commands, and current commands.

[0012] Optionally, the encoding subdivision processing module determines the region where the electrical angle is located, including:

[0013] The initial state of the signal from the Hall sensor is acquired to determine the initial sector for motor startup;

[0014] After the motor starts running, the signal from the Hall sensor is collected again to determine the current area of ​​motor rotation.

[0015] Optionally, determining the motor position based on the DSP's processing result of the sampled current includes:

[0016] The electrical angle of the motor's operation is determined based on the differences in the sector where the motor is located.

[0017] The motor's position is calculated based on the electrical angle of the motor's rotation and the signal from the Hall sensor.

[0018] Optionally, calculating the motor's position based on the electrical angle of the motor's operation and the signal from the Hall sensor includes:

[0019] Receive the HA and HB pulse signals corresponding to when the motor runs to the current sector;

[0020] When entering the next PWM interrupt handler function, the initial electrical angle value θ e The calculated result of the pulse difference COUNT*7.5° between the two interruptions is the electrical angle position of the motor in the current cycle.

[0021] A second aspect of the present invention provides a control device for an EPS system, the control device comprising:

[0022] The current sampling module is used to sample the motor current after receiving the drive command sent by the host computer, and then process the sampled current through the DSP and send it to the encoding subdivision processing module.

[0023] The encoder signal acquisition module is used to acquire the electrical angle of the motor operation fed back by the encoder and send the acquired electrical angle value to the encoding subdivision processing module. The angle of rotation of the motor in one revolution is divided into 6 sectors.

[0024] The encoding subdivision processing module is used to determine the region where the electrical angle is located, and to determine the position of the motor based on the processing result of the sampled current obtained by the DSP.

[0025] Optionally, the drive commands sent by the host computer include position commands, speed commands, and current commands.

[0026] Optionally, the encoding subdivision processing module is used to: determine the region where the electrical angle is located.

[0027] The initial state of the signal from the Hall sensor is acquired to determine the initial sector for motor startup;

[0028] After the motor starts running, the signal from the Hall sensor is collected again to determine the current area of ​​motor rotation.

[0029] Optionally, determining the motor position based on the DSP's processing result of the sampled current includes:

[0030] The electrical angle of the motor's operation is determined based on the differences in the sector where the motor is located.

[0031] The motor's position is calculated based on the electrical angle of the motor's rotation and the signal from the Hall sensor.

[0032] Optionally, calculating the motor's position based on the electrical angle of the motor's operation and the signal from the Hall sensor includes:

[0033] Receive the HA and HB pulse signals corresponding to when the motor runs to the current sector;

[0034] When entering the next PWM interrupt handler function, the initial electrical angle value θ e The calculated result of the pulse difference COUNT*7.5° between the two interruptions is the electrical angle position of the motor in the current cycle.

[0035] In the control method provided in this application, after receiving the drive command sent by the host computer, the motor current is sampled. The sampled current is processed by the DSP and then sent to the encoding subdivision processing module. The electrical angle of the motor rotation fed back by the encoder is collected and the collected electrical angle value is sent to the encoding subdivision processing module. The angle of rotation of the motor in one revolution is divided into 6 sectors. The encoding subdivision processing module determines the region where the electrical angle is located and determines the position of the motor based on the processing result of the sampled current by the DSP. The entire 360-degree rotation cycle is divided into 6 sectors, and the accurate position information is updated every 60 degrees, which improves the accuracy of the position information of the motor during rotation and enhances the control effect of the power steering system of the vehicle. Attached Figure Description

[0036] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0037] Figure 1 A schematic diagram illustrating the implementation flow of the control method for the EPS system provided in this embodiment of the invention;

[0038] Figure 2 This is an overall topology diagram of the EPS system provided in an embodiment of the present invention;

[0039] Figure 3 This is an example of encoder signal relationship diagram provided in an embodiment of the present invention;

[0040] Figure 4 Sector partitioning diagram provided for embodiments of the present invention;

[0041] Figure 5 A speed control flowchart provided for an embodiment of the present invention;

[0042] Figure 6 This is a schematic diagram of the control device for the EPS system provided in an embodiment of the present invention. Detailed Implementation

[0043] The technical problems solved by the embodiments of the present invention, the technical solutions adopted, and the practical applications will be described below with reference to the accompanying drawings and specific embodiments.

[0044] The technical effects are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other equivalent or obvious variations of embodiments obtained by those skilled in the art without creative effort fall within the protection scope of this invention. The embodiments of this invention can be embodied in various different ways as defined and covered by the claims.

[0045] It should be noted that many specific details are given in the following description for ease of understanding. However, it is obvious that the present invention may be implemented without these specific details.

[0046] It should be noted that, in the absence of explicit limitations or conflicts, the various embodiments and their technical features in this invention can be combined with each other to form a technical solution.

[0047] Example 1

[0048] Reference Figure 1 The control method of the EPS system of the present invention includes the following steps:

[0049] Step S101: After receiving the drive command sent by the host computer, the motor current is sampled, and the sampled current is processed by the DSP and then sent to the encoding subdivision processing module; the drive command sent by the host computer includes position command, speed command and current command.

[0050] Step S102: Collect the electrical angle of the motor operation fed back by the encoder, and send the collected electrical angle value to the encoding subdivision processing module. The angle of rotation of the motor in one revolution is divided into 6 sectors.

[0051] Specifically, the initial state of the Hall sensor signal is collected to determine the initial sector for motor startup; after the motor starts running, the Hall sensor signal is collected again to determine the current rotation area of ​​the motor. The electrical angle of motor operation is determined based on the difference in the motor's sector; the motor's position is calculated based on the electrical angle of motor operation and the Hall sensor signal.

[0052] The calculation of the motor's position based on the electrical angle of the motor's operation and the signal from the Hall sensor includes:

[0053] Receive the HA and HB pulse signals corresponding to when the motor runs to the current sector;

[0054] When entering the next PWM interrupt handler function, the initial electrical angle value θ e The calculated result of the pulse difference COUNT*7.5° between the two interruptions is the electrical angle position of the motor in the current cycle.

[0055] Step S103: The encoding subdivision processing module determines the region where the electrical angle is located, and determines the position of the motor based on the processing result of the sampled current obtained by the DSP.

[0056] The following is combined Figure 2-5 The above process will be explained as follows:

[0057] As attached Figure 2 As shown. The control method provided in this application can consist of three parts: core control, DSP peripheral modules and encoder signal acquisition, and encoder subdivision processing.

[0058] First, the host computer sends instructions to the EPS driver, which can be position, speed, or current commands. Then, the EPS driver acquires the BLDC current as the input signal to the DSP peripheral; the encoder signal is received by the DSP's QEP peripheral and used as the input signal to the encoder subdivision processing unit; the output signals from these two parts then serve as the input signals to the core control unit. Finally, through the control of the core unit, the drive unit inverter outputs the three-phase voltage required for the motor's rotation to the BLDC.

[0059] The encoder subdivision processing module is the core component, as shown in the attached diagram. Figure 3 and 4 As shown, the encoder signal is... Figure 2 The use case is divided into 6 sectors. The initial starting angle is determined by acquiring the initial state of the HU, HV, and HW signal levels, and the real-time electrical angle processed in each PWM cycle is determined by the frequency of the HA and HB signals. Unlike traditional encoders of this type, after the motor starts, the position information is updated every 60 degrees based on the acquired HU, HV, and HW signal levels, improving the accuracy of the position information and thus enhancing the overall control effect of the EPS system.

[0060] Furthermore, we will use speed control as an example to illustrate the technical protection aspect.

[0061] The EPS driver speed command N is given by the host computer. nf =1000rpm, counterclockwise movement. After receiving the instruction from the host computer, the driver... Figure 2 The three main control modules enable the controlled motor to rotate at a given speed.

[0062] The implementation process for the core control components is shown in the attached document. Figure 5 As shown:

[0063] Step 1: After entering the DSP's PWM interrupt, acquire the current current and position information, and describe the position information processing section in detail. Figure 3It can be seen that, assuming that HU, HV, and HW change from 101 to 100 in the current cycle, the encoder feedback electrical angle information is updated to θ. e =60°, one electrical angle cycle consists of 12 HA and HB pulse signals, by Figure 4 It can be seen that one electrical angle cycle is divided into 6 sectors, so each sector corresponds to 2 HA and HB pulse signals. Since the DSP's QEP peripheral can realize the frequency multiplication function and output 8 new pulse signals, 60° can be divided into 8 equal parts, and each part corresponds to an electrical angle of 7.5°.

[0064] Step 2: When entering the next PWM interrupt handler function, update the initial electrical angle value θ. e The calculation of the pulse difference COUNT*7.5° between the two interrupts and the current real-time electrical angle position of the current cycle.

[0065] Repeat steps 1 and 2 above to complete one cycle of 360° rotation control.

[0066] Example 2

[0067] Figure 6 This is a schematic diagram of the structure of a control device for an EPS system provided in Embodiment 2 of the present invention. For ease of explanation, only the parts related to the embodiments of the present invention are shown.

[0068] The control device includes:

[0069] The current sampling module 61 is used to sample the motor current after receiving the drive command sent by the host computer, process the sampled current through the DSP and send it to the encoding subdivision processing module.

[0070] The encoder signal acquisition module 62 is used to acquire the electrical angle of the motor operation fed back by the encoder and send the acquired electrical angle value to the encoder subdivision processing module. The angle of rotation of the motor in one revolution is divided into 6 sectors.

[0071] The encoding subdivision processing module 63 is used to determine the region where the electrical angle is located, and to determine the position of the motor based on the processing result of the sampled current obtained by the DSP.

[0072] Optionally, the drive commands sent by the host computer include position commands, speed commands, and current commands.

[0073] Optionally, the encoding subdivision processing module is used to: determine the region where the electrical angle is located.

[0074] The initial state of the signal from the Hall sensor is acquired to determine the initial sector for motor startup;

[0075] After the motor starts running, the signal from the Hall sensor is collected again to determine the current area of ​​motor rotation.

[0076] Optionally, determining the motor position based on the DSP's processing result of the sampled current includes:

[0077] The electrical angle of the motor's operation is determined based on the differences in the sector where the motor is located.

[0078] The motor's position is calculated based on the electrical angle of the motor's rotation and the signal from the Hall sensor.

[0079] Optionally, calculating the motor's position based on the electrical angle of the motor's operation and the signal from the Hall sensor includes:

[0080] Receive the HA and HB pulse signals corresponding to when the motor runs to the current sector;

[0081] When entering the next PWM interrupt handler function, the initial electrical angle value θ e The calculated result of the pulse difference COUNT*7.5° between the two interruptions is the electrical angle position of the motor in the current cycle.

[0082] The operation process of the control device of the EPS system is described above in the implementation process based on the control method, and will not be repeated here.

[0083] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0084] Those skilled in the art will recognize that the modules, units, and / or method steps of the various embodiments described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0085] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for an EPS system, characterized in that, The control method includes: After receiving the drive command sent by the host computer, the motor current is sampled, and the sampled current is processed by the DSP and then sent to the encoding subdivision processing module. The electrical angle of the motor rotation fed back by the encoder is collected and the collected electrical angle value is sent to the encoding subdivision processing module. The angle of rotation of the motor in one revolution is divided into 6 sectors. The encoding subdivision processing module determines the region where the electrical angle is located, and determines the position of the motor based on the processing result of the sampled current obtained by the DSP; The encoding subdivision processing module determines the region where the electrical angle is located, including: The initial state of the signal from the Hall sensor is acquired to determine the initial sector for motor startup; After the motor starts running, the signal from the Hall sensor is collected again to determine the current area of ​​motor rotation. The step of determining the motor position based on the DSP's processing result of the sampled current includes: The electrical angle of the motor's operation is determined based on the differences in the sector where the motor is located. The position of the motor is calculated based on the electrical angle of the motor's operation and the signal from the Hall sensor. The calculation of the motor's position based on the electrical angle of the motor's operation and the signal from the Hall sensor includes: Receive the HA and HB pulse signals corresponding to when the motor runs to the current sector; When entering the next PWM interrupt handler function, the initial value of the electrical angle is... The calculated result of the pulse difference COUNT*7.5° between the two interruptions is the electrical angle position of the motor in the current cycle.

2. The control method for an EPS system according to claim 1, characterized in that, The drive commands sent by the host computer include position commands, speed commands, and current commands.

3. The control method for an EPS system according to claim 1, implemented based on a control device, is characterized in that, The control device includes: The current sampling module is used to sample the motor current after receiving the drive command sent by the host computer, and then process the sampled current through the DSP and send it to the encoding subdivision processing module. The encoder signal acquisition module is used to acquire the electrical angle of the motor operation fed back by the encoder and send the acquired electrical angle value to the encoding subdivision processing module. The angle of rotation of the motor in one revolution is divided into 6 sectors. The encoding subdivision processing module is used to determine the region where the electrical angle is located, and to determine the position of the motor based on the processing result of the sampled current obtained by the DSP; The encoding subdivision processing module is used to: determine the region where the electrical angle is located. The initial state of the signal from the Hall sensor is acquired to determine the initial sector for motor startup; After the motor starts running, the signal from the Hall sensor is collected again to determine the current area of ​​motor rotation. The step of determining the motor position based on the DSP's processing result of the sampled current includes: The electrical angle of the motor's operation is determined based on the differences in the sector where the motor is located. The position of the motor is calculated based on the electrical angle of the motor's operation and the signal from the Hall sensor. The calculation of the motor's position based on the electrical angle of the motor's operation and the signal from the Hall sensor includes: Receive the HA and HB pulse signals corresponding to when the motor runs to the current sector; When entering the next PWM interrupt handler function, the initial value of the electrical angle is... The calculated result of the pulse difference COUNT*7.5° between the two interruptions is the electrical angle position of the motor in the current cycle.

4. The control method for an EPS system according to claim 3, characterized in that, The drive commands sent by the host computer include position commands, speed commands, and current commands.

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