Field current control method, system, vehicle, device, medium, and program product

Abstract

The application relates to an excitation current control method, system, vehicle, device, medium and program product. The method comprises the following steps: in the case that it is detected that an executing load has left a resistance point, switching off a switching device in a three-phase full-bridge circuit; in the case that the amplitudes of three-phase currents in the three-phase full-bridge circuit are all less than or equal to a preset current threshold value, switching on the switching device in the three-phase full-bridge circuit, and increasing an excitation current reference value to a first target current value; in the case that it is detected that an actual excitation current reaches the first target current value, indicating that an angle difference between an estimated electric angle of a current observer for a motor rotor and an actual angle of the motor rotor is less than or equal to an angle difference threshold value, and reducing the excitation current reference value from the first target current value to a second target current value. By using the method, smooth switching from open loop to FOC closed loop can be quickly and reliably completed after the executing load leaves the resistance point.

Description

Technical Field

[0001] This application relates to the field of excitation current control technology, and in particular to an excitation current control method, system, vehicle, equipment, medium, and program product. Background Technology

[0002] As people's demands for car aesthetics have increased, concealed windshield wipers have emerged. Concealed wipers are usually hidden under the vehicle's trim panel, and only pop out from under the trim panel to clean the windshield when needed.

[0003] To make the wipers pop out from under the trim panel, the motor needs to be controlled using a high-current open-loop push method to ensure that the wipers can reliably pop out of the trim panel by overcoming high mechanical resistance under the motor's drive. To ensure smooth operation of the wipers, the motor needs to quickly switch into FOC (Field-Oriented Control) closed-loop control after the wipers pop out. However, in this case, the estimated electrical angle of the motor rotor by the current-type observer in the motor is forcibly fed in by the open-loop command, and the high current will overwhelm the back EMF information, causing the current-type observer to fail to converge to the actual angle of the motor rotor. This may lead to adverse phenomena such as motor step loss, vibration, and abnormal noise, which affect the normal operation of the wipers. Summary of the Invention

[0004] Therefore, it is necessary to provide an excitation current control method, system, vehicle, computer equipment, computer-readable storage medium, and computer program product that can quickly and reliably complete the smooth switching from open-loop to FOC closed-loop after the load leaves the resistance point, in order to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides an excitation current control method, the method comprising:

[0006] When it is detected that the load has moved away from the resistance point, the switching devices in the three-phase full-bridge circuit are turned off.

[0007] When the amplitude of the three-phase current in the three-phase full-bridge circuit is less than or equal to the preset current threshold, the switching device in the three-phase full-bridge circuit is turned on, and the excitation current reference value is increased to the first target current value.

[0008] The actual excitation current is determined based on the voltage across the sampling resistor and the resistance value of the sampling resistor in the three-phase full-bridge circuit.

[0009] If the actual excitation current is detected to reach the first target current value, it means that the angle difference between the estimated electrical angle of the motor rotor and the actual angle of the motor rotor by the current-type observer is less than or equal to the angle difference threshold, and the excitation current reference value is reduced from the first target current value to the second target current value.

[0010] In one exemplary embodiment, the method further includes:

[0011] When it is detected that the load needs to be removed from the resistance point, the three-phase full-bridge circuit provides the motor with a current corresponding to the third target current value, so as to instruct the motor to work under the third target current value, so as to drive the load to move in the set direction, and the resistance point is located in the set direction.

[0012] In one exemplary embodiment, a Hall sensor element is provided at the location of the resistance point of the applied load;

[0013] The step of turning off the switching devices in the three-phase full-bridge circuit when it is detected that the load has moved away from the resistance point includes:

[0014] If the Hall output value of the Hall sensor is collected, it is determined that the load has moved away from the resistance point;

[0015] After confirming that the load has moved away from the resistance point, turn off the switching devices in the three-phase full-bridge circuit.

[0016] In one exemplary embodiment, the three-phase full-bridge circuit is connected to the pre-driver chip;

[0017] The switching devices in the three-phase full-bridge circuit that are turned off include:

[0018] By stopping the transmission of electrical signals to the pre-driver chip, the switching devices in the three-phase full-bridge circuit are turned off.

[0019] The switching devices in the conducting three-phase full-bridge circuit include:

[0020] The switching devices in the three-phase full-bridge circuit are turned on by resending an electrical signal to the pre-drive chip.

[0021] In one exemplary embodiment, the magnitude of the first target current value is 2 to 3 times the magnitude of the second target current value.

[0022] In an exemplary embodiment, the step of reducing the excitation current reference value from the first target current value to the second target current value when the actual excitation current is detected to have reached the first target current value includes:

[0023] Detect the motor rotor speed and actual excitation current;

[0024] When the motor rotor speed is within the preset speed range and the actual excitation current increases to the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value; or,

[0025] Detect torque current and actual excitation current;

[0026] If the torque current is within the preset current range and the actual excitation current increases to the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value; or,

[0027] Detect the motor rotor speed, torque current, and actual excitation current;

[0028] When the motor rotor speed is within the preset speed range, the torque current is within the preset current range, and the actual excitation current increases to the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value.

[0029] In one exemplary embodiment, the method further includes:

[0030] Noise current is collected when no current flows through a three-phase full-bridge circuit.

[0031] Based on the noise current and the current margin, a preset current threshold is determined.

[0032] In an exemplary embodiment, determining the preset current threshold based on the noise current and the current margin includes:

[0033] The preset current threshold is determined based on noise current, current margin, and temperature compensation.

[0034] In an exemplary embodiment, the step of turning on the switching devices in the three-phase full-bridge circuit and increasing the excitation current reference value to the first target current value when the amplitudes of the three-phase currents in the three-phase full-bridge circuit are all less than or equal to a preset current threshold includes:

[0035] Determine the actual bus voltage;

[0036] The dynamic scaling value for the preset current threshold is determined based on the actual bus voltage;

[0037] The preset current threshold is scaled based on the dynamic scaling value to obtain the scaled current threshold.

[0038] When the amplitudes of the three-phase currents in the three-phase full-bridge circuit are all less than or equal to the scaled current threshold, the switching devices in the three-phase full-bridge circuit are turned on, and the excitation current reference value is increased to the first target current value.

[0039] In one exemplary embodiment, the load is the windshield wiper, and the resistance point is the location of the wiper outlet.

[0040] Secondly, this application also provides an excitation current control system, the system including an execution load, a motor and a controller, the controller including a three-phase full-bridge circuit, the three-phase full-bridge circuit being connected to the motor, and the motor being connected to the execution load;

[0041] The controller is used to implement the steps of the method described in any of the first aspects of this application.

[0042] Thirdly, this application also provides a vehicle that includes an excitation current control system as described in the second aspect of this application.

[0043] Fourthly, this application also provides a computer device. The computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement some or all of the steps described in any method of the first aspect of the embodiments of this application.

[0044] Fifthly, this application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements some or all of the steps described in any method of the first aspect of the embodiments of this application.

[0045] Sixthly, this application also provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements some or all of the steps described in any method of the first aspect of the embodiments of this application.

[0046] The aforementioned excitation current control method, system, vehicle, computer equipment, computer-readable storage medium, and computer program product, upon detecting that the load has moved away from the resistance point, do not directly switch to the FOC closed loop. Instead, they turn off the switching devices in the three-phase full-bridge circuit, allowing the three-phase current to flow freely. When the amplitudes of the three-phase currents are relatively small, they then turn the switching devices in the three-phase full-bridge circuit back on to re-engage the FOC closed loop. Furthermore, by increasing the excitation current reference value to a first target current value greater than the steady-state value, they provide excitation current to the current-type observer to accelerate the convergence speed of its estimated electrical angle towards the actual angle of the motor rotor. When the actual excitation current reaches the first target current value, it indicates that the angle difference between the estimated electrical angle of the motor rotor and the actual angle of the motor rotor is less than or equal to the angle difference threshold. In this case, the excitation current reference value is reduced from the first target current value to the second target current value. Thus, a smooth switch from open loop to FOC closed loop is completed. As can be seen, the method of this embodiment does not require explicit angle alignment. It can quickly and reliably complete the smooth switching from open loop to FOC closed loop after the load leaves the resistance point. By avoiding entering FOC closed loop before the estimated electrical angle has converged, it can not only avoid adverse phenomena such as motor step loss, vibration, and abnormal noise, but also make the entire FOC closed loop process imperceptible to the user. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A structural block diagram of an excitation current control system provided in this application embodiment;

[0049] Figure 2 A flowchart illustrating an excitation current control method provided in an embodiment of this application;

[0050] Figure 3 A schematic flowchart of another excitation current control method provided in an embodiment of this application;

[0051] Figure 4 A structural block diagram of a vehicle provided in an embodiment of this application;

[0052] Figure 5 This is an internal structural diagram of a computer device provided in an embodiment of this application. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0054] The excitation current control method provided in this application embodiment can be applied to, for example... Figure 1 The excitation current control system 100 shown includes a controller 102. The excitation current control system 100 includes an execution load 104, a motor 106, and a controller 102. The controller 102 includes a three-phase full-bridge circuit 1022, which is connected to the motor 106. The motor 106 is connected to the execution load 104. The controller 102 is used to implement the steps of the excitation current control method provided in this embodiment.

[0055] An execution load is a load that is connected to a motor, driven by the motor, and outputs mechanical work to the outside.

[0056] Alternatively, the motor can be a brushless motor.

[0057] Optionally, the controller may also include a microcontroller unit (MCU), which is connected to a three-phase full-bridge circuit.

[0058] A three-phase full-bridge circuit is a circuit consisting of six switching devices connected to the three-phase stator windings of a motor. The three-phase full-bridge circuit includes three bridge arms, each corresponding to the U, V, and W phases of the motor. Each bridge arm is formed by connecting an upper and lower transistor in series, creating an upper bridge arm and a lower bridge arm. The connection point between the upper and lower transistors is led out to the motor stator windings. Each lower bridge arm is connected in series with a sampling resistor to collect the phase current and feed it back to the controller.

[0059] It should be noted that the three-phase full-bridge circuit in this embodiment is a mature standard topology in the field of power electronics. Therefore, the specific circuit structure of the three-phase full-bridge circuit is not illustrated in this embodiment.

[0060] In one exemplary embodiment, such as Figure 2 As shown, an excitation current control method is provided, which is applied to... Figure 1 The controller in the process includes the following steps 202 to 208. Wherein:

[0061] Step 202: When it is detected that the load has moved away from the resistance point, the switching devices in the three-phase full-bridge circuit are turned off.

[0062] Optionally, the load being executed can be a windshield wiper, pump, valve, etc.

[0063] The resistance point is the location where the load experiences the greatest resistance during its movement in a set direction. It can also be understood as the point where the equivalent load torque reaches its maximum value during the load's movement in the set direction.

[0064] Optionally, the direction can be set, which can refer to a horizontal direction from right to left or a horizontal direction from left to right.

[0065] This can be understood as follows: in order for the load to perform its function smoothly, it must move along its set direction to pass the resistance point, i.e., leave the resistance point. If the motor cannot drive the load to leave the resistance point, the load cannot perform its function.

[0066] For example, when the load is a windshield wiper, the wiper can be a hidden wiper or a pop-up wiper, and the resistance point is the location where the wiper outlet is located. That is, the resistance point is the location point that causes the wiper to switch from a hidden state to a non-hidden state. Switching the wiper from a hidden state to a non-hidden state can be understood as the wiper popping out from the location of the outlet.

[0067] As a further example, the resistance point can be the location where the wiper makes direct contact with the trim panel. Based on this, if the wiper cannot disengage from the resistance point, the wiper cannot pop up to clean the windshield or the vehicle's lidar glass surface.

[0068] Optionally, the six switching devices included in the three-phase full-bridge circuit can be MOS (Metal-Oxide-Semiconductor Field-Effect Transistor) or IGBT (Insulated Gate Bipolar Transistor).

[0069] Optionally, the switching devices in the three-phase full-bridge circuit can be turned off by either connecting the controller to the pre-drive chip and stopping the transmission of electrical signals to the pre-drive chip, or by reducing the duty cycle of the drive signals provided to the switching devices in the three-phase full-bridge circuit. Compared to turning off the switching devices by reducing the duty cycle of the drive signals provided to the switching devices in the three-phase full-bridge circuit, stopping the transmission of electrical signals to the pre-drive chip allows for faster and more direct turn-off of the switching devices.

[0070] After the switching devices in the three-phase full-bridge circuit are turned off, the residual current in the three-phase windings can only be discharged quickly and freely through the body diodes of each switching device. Based on this, the three-phase current will gradually decrease. During this process, the motor rotor will slide freely under inertia.

[0071] After the switching devices in the three-phase full-bridge circuit are turned off, the current-type observer cannot be excited by current, so the estimated electrical angle of the current-type observer is unreliable. That is to say, the estimated electrical angle output by the current-type observer will be regarded as an invalid signal before the switching devices in the three-phase full-bridge circuit are turned back on.

[0072] Step 204: When the amplitude of the three-phase current in the three-phase full-bridge circuit is less than or equal to the preset current threshold, turn on the switching device in the three-phase full-bridge circuit and increase the excitation current reference value to the first target current value.

[0073] Optionally, the controller can detect the three-phase current amplitude in real time using an ADC (Analog-to-Digital Converter) connected to a three-phase full-bridge circuit.

[0074] The preset current threshold is a current threshold close to zero. It can be understood as a threshold indicating whether the three-phase current has been completely discharged after the switching devices in a three-phase full-bridge circuit have been turned off. Optionally, the preset current threshold can be 0, 0.01A, 0.05A, or other near-zero current values.

[0075] The three-phase current amplitudes are all less than or equal to the preset current threshold, which means that the amplitudes of the three-phase currents U, V, and W are all less than or equal to the preset current threshold.

[0076] Optionally, the switching devices in the three-phase full-bridge circuit can be turned on by the controller connecting to the pre-drive chip and re-sending electrical signals to the pre-drive chip, or by increasing the duty cycle of the drive signal provided to the switching devices in the three-phase full-bridge circuit. Compared to turning off the switching devices by increasing the duty cycle of the drive signal provided to the switching devices in the three-phase full-bridge circuit, continuing to send electrical signals to the pre-drive chip can turn on the switching devices faster and more directly.

[0077] The excitation current reference value refers to the current reference value set by the user in the rotating coordinate system of FOC, composed of the d-axis and q-axis, used to control the strength of the internal magnetic field of the motor, and corresponding to the d-axis current. In the rotating coordinate system of FOC, the d-axis current is the excitation current, and the q-axis current is the torque current. The excitation current and torque current are orthogonal. The excitation current is aligned with the direction of the motor rotor magnetic field, and the torque current leads the excitation current by 90° electrical angle to generate torque.

[0078] The first target current value is greater than the steady-state current value of the motor, which can be understood as the first target current value being greater than the current value required to maintain the load movement at the rated speed.

[0079] The process of increasing the excitation current reference value to the first target current value can be as follows: The current PI (Proportional-Integral) regulator in the controller calculates the required d-axis voltage based on the first target current value set by the user, performs SVPWM (Space Vector Pulse Width Modulation) conversion on the d-axis voltage to obtain the duty cycle of the switching devices in the three-phase full-bridge circuit, and drives the switching devices in the three-phase full-bridge circuit to work based on the duty cycle.

[0080] After the switching devices in the three-phase full-bridge circuit operate according to the duty cycle corresponding to the first target current value, the three-phase full-bridge circuit will drive the motor to rotate to provide current excitation. The current-type observation will take the three-phase current, i.e. the motor stator current signal and the known motor mathematical model as input, quickly establish the estimated electrical angle and converge the estimated electrical angle to the actual angle of the motor rotor. The converged estimated electrical angle is then fed back to the inverse PARK transform to adjust the motor rotor angle. Thus, the FOC closed loop is realized.

[0081] It can be seen that step 204 uses the near-zero amplitude of the three-phase current obtained by real-time detection as the adaptive termination criterion. That is, when the amplitude of the three-phase current in the three-phase full-bridge circuit is less than or equal to the preset current threshold, the free-flow discharge time window is considered to have ended. Based on this method, compared with the use of a fixed delay time window, this embodiment can achieve adaptation to the mechanical resistance, pop-out overshoot, and power supply state experienced by different execution loads during the process of leaving the resistance point.

[0082] Increasing the excitation current reference value to the first target current value is equivalent to providing a sufficiently large current excitation for the current-type sensorless observer, enabling the current-type observer to quickly establish the estimated electrical angle and converge the estimated electrical angle to the actual angle of the motor rotor.

[0083] Step 206: Determine the actual excitation current based on the voltage across the sampling resistor in the three-phase full-bridge circuit and the resistance value of the sampling resistor.

[0084] The sampling resistor is a resistor connected in series on the DC bus side or the three-phase output side of a three-phase full-bridge inverter circuit (usually located between the lower bridge arm and ground) to convert the instantaneous large current flowing through the motor windings into a differential voltage signal according to a proportional relationship.

[0085] Based on the voltage across the sampling resistor and the resistance value of the sampling resistor in the three-phase full-bridge circuit, the three-phase current is determined. After performing Clarke and Park transformations on the three-phase current, the actual instantaneous current in the d-axis direction in the FOC rotating coordinate system is the actual excitation current, and the actual instantaneous current in the q-axis direction in the FOC rotating coordinate system is the actual torque current.

[0086] It should be noted that after increasing the excitation current reference value to the first target current value, the current PI regulator will match the first target current value with the actual excitation current in real time. Based on the matching result, the required d-axis voltage will be adjusted in real time to accurately adjust the actual excitation current to the first target current value. Accordingly, the duty cycle of the switching devices in the three-phase full-bridge circuit is also adjusted in real time. It can be seen that the integral action of the current PI regulator can eliminate steady-state errors, ensuring that the actual excitation current reaches the first target current value.

[0087] Step 208: If the actual excitation current is detected to reach the first target current value, it means that the angle difference between the estimated electrical angle of the motor rotor by the current-type observer and the actual angle of the motor rotor is less than or equal to the angle difference threshold, and the excitation current reference value is reduced from the first target current value to the second target current value.

[0088] Among them, the current-type observer refers to an observer in FOC that relies solely on the motor stator current signal and the known mathematical model of the motor to calculate the actual angle of the motor rotor by reconstructing the back electromotive force.

[0089] The estimated electrical angle of a motor rotor by a current-type observer refers to a virtual calculated electrical angle that is calculated and output in real time by the current-type observer based on the stator phase current and the motor mathematical model. This angle represents the spatial phase of the permanent magnet flux linkage axis of the motor rotor in the stator coordinate system.

[0090] When the angle difference between the estimated electrical angle and the actual angle of the motor rotor is less than or equal to the angle difference threshold, it means that the estimated electrical angle has converged towards the actual angle of the motor rotor. In other words, the current-type observer has achieved steady-state convergence of the motor rotor position. This can also be understood as the current loop catching up, and the estimated electrical angle of the current-type observer aligning with the actual angle of the motor rotor. Therefore, the excitation current reference value is reduced from the first target current value to the second target current value corresponding to the steady-state value to maintain normal FOC closed-loop operation. Based on this, both the convergence speed of the estimated electrical angle and the efficiency of the motor entering steady-state operation can be considered.

[0091] Optionally, the angle difference threshold can be an angle difference of 0.5°, 1°, or other numerical values.

[0092] Optionally, the second target current value can correspond to the steady-state current value of the motor, that is, the second target current value can be the current value required to maintain the motion of the load at the rated motion speed.

[0093] Optionally, the first target current value can be 0.10, 0.15, or other values ​​of the peak current that the motor can withstand. That is, based on the peak current that the motor can withstand, the first target current value can be set to 0.10, 0.15, or other values; the second target current value can be 0.05 or other values ​​of the peak current that the motor can withstand. That is, based on the peak current that the motor can withstand, the second target current value can be set to 0.05 or other values.

[0094] This can be understood as follows: the purpose of making the actual excitation current reach the first target current value is to provide sufficient current excitation so that the current-type observer can converge quickly. That is, the angle difference between the estimated electrical angle of the motor rotor by the current-type observer and the actual angle of the motor rotor is less than or equal to the angle difference threshold. Therefore, after the convergence is completed, the excitation current reference value is reduced from the first target current value to the second target current value so that the motor can operate in steady state and achieve FOC closed-loop control.

[0095] Since this embodiment does not rely on any sensors (for example, sensors such as Hall elements, photoelectric encoders, rotary transformers, etc.) to obtain the actual angle of the motor rotor, the FOC closed-loop control in this embodiment refers to sensorless FOC closed-loop control.

[0096] In the above-described excitation current control method, when it is detected that the load has moved away from the resistance point, the system does not directly switch to the FOC closed loop. Instead, it turns off the switching devices in the three-phase full-bridge circuit, allowing the three-phase current to flow freely. When the amplitudes of the three-phase currents are relatively small, the switching devices in the three-phase full-bridge circuit are turned on again to re-engage the FOC closed loop. Furthermore, by increasing the excitation current reference value to a first target current value greater than the steady-state value, an excitation current is provided to the current-type observer to accelerate the convergence speed of its estimated electrical angle towards the actual angle of the motor rotor. When it is detected that the actual excitation current has reached the first target current value, it indicates that the angle difference between the estimated electrical angle of the motor rotor by the current-type observer and the actual angle of the motor rotor is less than or equal to the angle difference threshold. Then, the excitation current reference value is reduced from the first target current value to the second target current value. Thus, the smooth switching from open loop to FOC closed loop is completed. As can be seen, the method of this embodiment does not require explicit angle alignment. It can quickly and reliably complete the smooth switching from open loop to FOC closed loop after the load leaves the resistance point. By avoiding entering FOC closed loop before the estimated electrical angle has converged, it can not only avoid adverse phenomena such as motor step loss, vibration, and abnormal noise, but also make the entire FOC closed loop process imperceptible to the user.

[0097] In this embodiment, no position sensor is provided. Based on this, the current loop of the controller can only operate in the dq coordinate system estimated by the current-type observer. That is, the controller will apply the d-axis voltage to provide excitation current according to "the rotor angle it assumes".

[0098] When the estimated electrical angle of the current-type observer is aligned with the actual angle of the motor rotor, the controller will apply a d-axis voltage to "what it thinks is the d-axis". This d-axis voltage happens to fall on the actual d-axis of the motor rotor. Based on this, the d-axis voltage excitation is almost entirely applied to the actual d-axis, generating only excitation current and basically no torque. Therefore, the actual excitation current will increase to the first target current value.

[0099] When there is a deviation between the estimated electrical angle of the current-type observer and the actual angle of the motor rotor, the controller assumes that it is applying a d-axis voltage to the actual d-axis of the motor rotor. However, in reality, a portion of this d-axis voltage leaks onto the q-axis, causing the q-axis current to generate a corresponding torque, which in turn causes the motor rotor to rotate and the back electromotive force to change. These phenomena, in turn, interfere with the magnitude of the excitation current, preventing the actual excitation current from increasing effectively, or causing it to increase very slowly or fluctuate wildly, i.e., "jittering". In other words, as long as the estimated electrical angle of the current-type observer cannot converge effectively, the actual excitation current will be difficult to increase to the first target current value.

[0100] During the excitation process of the current-type observer, which is excited by the excitation current reference value corresponding to the first target current value, the deviation angle between the estimated electrical angle and the actual angle of the motor rotor will automatically converge to 0. Therefore, in this embodiment, since the actual excitation current is calculated by the estimated electrical angle through Park transformation and the current PI works in the same estimation coordinate system, its integration effect will cause the steady-state actual excitation current to tend to the reference value. Therefore, "the actual excitation current reaches the first target current value" can be used as a necessary proxy indicator for the convergence of the estimated electrical angle. Optionally, in order to eliminate the false convergence of "the measured excitation current reaches the reference value" under extreme deviation angles, the estimated electrical angle can also be determined by combining the three conditions of "the actual excitation current stably reaches the first target current value within a preset time threshold, and the motor rotor speed is within a preset speed range and the torque current is within a preset current range".

[0101] In an exemplary embodiment, when the actual excitation current is detected to have reached a first target current value, reducing the excitation current reference value from the first target current value to a second target current value includes:

[0102] Detect the motor rotor speed and actual excitation current;

[0103] When the motor rotor speed is within the preset speed range and the actual excitation current increases to the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value; or,

[0104] Detect torque current and actual excitation current;

[0105] If the torque current is within the preset current range and the actual excitation current increases to the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value; or,

[0106] Detect the motor rotor speed, torque current, and actual excitation current;

[0107] When the motor rotor speed is within the preset speed range, the torque current is within the preset current range, and the actual excitation current increases to the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value.

[0108] The preset speed range corresponds to the rated speed range of the motor. Based on this, the motor rotor speed being within the preset speed range indicates that there is no abnormality in the motor rotor speed.

[0109] Ensuring that the motor rotor speed is within the preset speed range is to ensure that the motor rotor does not experience any abnormal conditions such as jumps, divergence, or discrepancies with the Hall effect measurement value, which could lead to false convergence of the current-type observer.

[0110] The torque current being within the preset current range indicates that there are no abnormalities in the torque current of the motor.

[0111] Optionally, the torque current being within a preset current range can mean that the amplitude of the torque current is within a preset current amplitude range, and the direction of the torque current is within a preset direction range. This avoids undesirable situations where the current-type observer might experience false convergence, such as abnormally large or small amplitudes or abnormal directions of the torque current.

[0112] The motor rotor speed is within the preset speed range, and the torque current is within the preset current range, indicating that there is no abnormality in the motor rotor speed and the motor torque current.

[0113] In this embodiment, for applications with higher reliability requirements, the motor rotor speed, torque current, and any combination thereof can be combined with the actual excitation current to form a multi-criteria redundancy anti-false convergence mechanism. This mechanism avoids false convergence situations where the actual excitation current has increased to the first target current value, but the motor rotor speed and / or torque current are abnormal. This further improves the robustness of the FOC closed loop and the safety of the executed load.

[0114] In an exemplary embodiment, the above-mentioned reduction of the excitation current reference value from the first target current value to the second target current value when the actual excitation current is detected to reach the first target current value indicates that the angle difference between the estimated electrical angle of the motor rotor by the current-type observer and the actual angle of the motor rotor is less than or equal to the angle difference threshold includes:

[0115] If the actual excitation current is detected to reach the first target current value within a preset time threshold, it means that the angle difference between the estimated electrical angle of the motor rotor and the actual angle of the motor rotor by the current-type observer is less than or equal to the angle difference threshold, and the excitation current reference value is reduced from the first target current value to the second target current value.

[0116] In one exemplary embodiment, the method further includes:

[0117] When it is detected that the load needs to be removed from the resistance point, the three-phase full-bridge circuit provides the motor with a current corresponding to the third target current value, so as to instruct the motor to work under the third target current value, so as to drive the load to move in the set direction, and the resistance point is located in the set direction.

[0118] This could be achieved when the controller receives an execution command for the execution load and determines that the execution load needs to move away from the resistance point.

[0119] For example, when the load being executed is the windshield wipers, the execution command may be generated by the vehicle's central control system and transmitted to the controller. In this case, the execution command is used to instruct the windshield wipers to clean the windshield or the vehicle's lidar glass surface.

[0120] Optionally, the third target current value can be 0.7, 0.75, 0.8, or other values ​​of the peak current that the motor can withstand. That is, based on the peak current that the motor can withstand, the third target current value can be set to 0.7, 0.75, 0.8, or other values. The peak current that the motor can withstand is greater than the rated current of the motor. Based on this, providing the motor with a current corresponding to the third target current value can be understood as providing the motor with a large open-loop current, so that the electromagnetic torque generated by this large current will force the load out of the resistance point.

[0121] Since the large current is to provide the electromagnetic torque that enables the load to move away from the resistance point, the current corresponding to the third target current value is the torque current, i.e., the q-axis current. Since the resistance point is located in the set direction, the current corresponding to the third target current value is applied along the set direction of the load, i.e., the direction of the current corresponding to the third target current value is the same as the direction of movement of the load along the resistance point.

[0122] Optionally, the time point at which the execution load needs to leave the resistance point can be when the execution load is at the starting position in its direction of movement, or when the execution load has already moved along the direction of movement and the distance between its position and the resistance point is less than or equal to a distance threshold.

[0123] The time window during which the three-phase current can freely flow and rapidly discharge after the switching devices in a three-phase full-bridge circuit are turned off is to reset the electrical transients left by the current open loop corresponding to the third target current value to a clean state that can be re-entered into the FOC closed loop.

[0124] In this embodiment, when it is detected that the load needs to move away from the resistance point, in order to avoid the conventional electromagnetic torque being insufficient to ensure that the load moves past the resistance point, a large current needs to be temporarily injected into the motor when the load is close to the resistance point so that the motor generates a large electromagnetic torque. The motor is supplied with a current corresponding to the third target current value through the three-phase full-bridge circuit to instruct the motor to work at the third target current value, so as to drive the load to move in the set direction and successfully move away from the resistance point based on the large electromagnetic torque. It can be understood that the way the load moves away from the resistance point in this embodiment is a large current open-loop forced push method. Based on this large current open-loop forced push method, it can ensure that the load moves away from the resistance point smoothly to achieve its functional role.

[0125] Meanwhile, in this embodiment, which uses a high-current open-loop push method to achieve the load separation from the resistance point, the switching devices in the three-phase full-bridge circuit will only be turned on when the amplitude of the three-phase current in the three-phase full-bridge circuit is less than or equal to the preset current threshold, that is, when the amplitude of the three-phase current is close to zero. Therefore, there is no electrical angle drive during the process of the motor re-entering the FOC closed loop. Thus, this embodiment does not need to and cannot perform continuity between the open-loop command angle and the estimated electrical angle. The smoothness between the open-loop command angle and the estimated electrical angle is guaranteed by the "current zero reset mechanism" ensured by the preset current threshold and the "current fast relock mechanism" that increases the excitation current reference value to the first target current value. As a result, the process of FOC re-entering the closed-loop control is invisible to the user's naked eye.

[0126] In one exemplary embodiment, a Hall sensor element is provided at the location of the resistance point of the applied load;

[0127] The above-mentioned action of turning off the switching devices in the three-phase full-bridge circuit when the load has been detected to have moved away from the resistance point includes:

[0128] If the Hall output value of the Hall sensor is collected, it is determined that the load has moved away from the resistance point;

[0129] After confirming that the load has moved away from the resistance point, turn off the switching devices in the three-phase full-bridge circuit.

[0130] The Hall sensor element is positioned to correspond to the location of the resistance point. Based on this, when the load has moved away from the resistance point, it indicates that the load has passed the Hall sensor element. Therefore, the Hall sensor element will output a Hall output value so that the controller can determine that the load has moved away from the resistance point.

[0131] Since a Hall sensor is located at the resistance point of the load, the load will inevitably pass through the Hall sensor once it leaves the resistance point.

[0132] Optionally, since the load has a fixed mechanical stroke from the starting point to the resistance point, which corresponds to the motor rotating through a fixed angle, the first Hall transition edge of the Hall sensor element can be calibrated as detecting that the load has moved away from the resistance point.

[0133] Optionally, the Hall sensing element may include at least one Hall sensor.

[0134] In this embodiment, a Hall sensor element is provided at the location of the resistance point of the load. Based on this, when the Hall output value of the Hall sensor element is collected, it is determined that the load has moved away from the resistance point, thereby turning off the switching devices in the three-phase full-bridge circuit. Based on this, by accurately determining that the load has moved away from the resistance point, the switching devices in the three-phase full-bridge circuit can be turned off at the accurate time point, so as to ensure that the smooth switching from open loop to FOC closed loop can be completed quickly and reliably.

[0135] Of course, this is not the only option. In addition to using Hall effect sensors to detect whether the load has moved away from the resistance point, specific encoder values ​​and IO feedback jump values ​​caused by external mechanical structures can also be used as the basis for determining whether the load has moved away from the resistance point.

[0136] In one exemplary embodiment, the three-phase full-bridge circuit is connected to the pre-driver chip;

[0137] The switching devices in the above-mentioned three-phase full-bridge circuit for turning off include:

[0138] By stopping the transmission of electrical signals to the pre-driver chip, the switching devices in the three-phase full-bridge circuit are turned off.

[0139] The switching devices in the above-mentioned conducting three-phase full-bridge circuit include:

[0140] The switching devices in the three-phase full-bridge circuit are turned on by resending an electrical signal to the pre-drive chip.

[0141] Optionally, the pre-drive chip is connected to the gate of the switching device in the three-phase full-bridge circuit so as to control the switching device to turn on or off by providing a control signal to the gate of the switching device.

[0142] Optionally, the pre-drive chip can be a dedicated three-phase pre-drive chip, a discrete half-bridge pre-drive chip, or other chips that can turn on or off the switching devices in a three-phase full-bridge circuit.

[0143] Optionally, the electrical signal sent by the controller to the pre-drive chip may be a signal used to keep the pre-drive chip in a conducting state so that the pre-drive chip can turn on or off the switching devices in the three-phase full-bridge circuit.

[0144] Stopping the transmission of electrical signals to the pre-driver chip enables the pre-driver chip to stop working and quickly turn off the switching devices in the three-phase full-bridge circuit.

[0145] After the electrical signals sent to the pre-driver chip are stopped and the switching devices in the three-phase full-bridge circuit are turned off, the three-phase current is allowed to freely flow through the body diodes of the switching devices. The time window for this freewheeling discharge is extremely short, on the order of milliseconds or sub-milliseconds.

[0146] Obviously, compared to the traditional method of turning off the switching devices in the three-phase full-bridge circuit by gradually reducing the duty cycle of the control signals sent to the switching devices in the three-phase full-bridge circuit, this embodiment can turn off the switching devices in the three-phase full-bridge circuit more quickly by stopping the sending of electrical signals to the pre-drive chip. Furthermore, after the switching devices are turned off, the three-phase current can be rapidly attenuated through the freewheeling current of the body diodes of the switching devices. That is, the amplitude of the three-phase current can be attenuated to less than or equal to the preset current threshold at a relatively fast speed. Therefore, this helps to ensure that the user is unaware of the entire FOC closed-loop process.

[0147] After the switching devices in the three-phase full-bridge circuit are turned off, the motor rotor continues to glide freely for a very small angle distance solely due to inertia, allowing the load to move away from the resistance point until the FOC closed loop is achieved. This entire process is imperceptible to the user's naked eye.

[0148] In this embodiment, since the three-phase full-bridge circuit is connected to the pre-drive chip, the switching devices in the three-phase full-bridge circuit can be turned off by stopping the transmission of electrical signals to the pre-drive chip, while the switching devices in the three-phase full-bridge circuit can be turned on by retransmitting electrical signals to the pre-drive chip. Therefore, compared with the traditional method of gradually reducing the duty cycle supplied to the switching devices in the three-phase full-bridge circuit, this embodiment can turn off the switching devices in the three-phase full-bridge circuit more quickly and make the three-phase current amplitude decay to near zero more quickly. That is to say, this embodiment can greatly reduce the length of the discharge window, thereby ensuring that the user is unaware of the entire FOC closed-loop process.

[0149] In one exemplary embodiment, the magnitude of the first target current value is 2 to 3 times the magnitude of the second target current value.

[0150] For example, if the second target current value is set to 0.05 based on the peak current that the motor can withstand, then the first target current value is set to 0.10~0.15.

[0151] In this embodiment, the first target current value is greater than the second target current value, and the magnitude of the first target current value is 2 to 3 times the magnitude of the second target current value. Based on this, when it is detected that the load needs to leave the resistance point, the three-phase full-bridge circuit provides the motor with a current corresponding to the first target current value, which is equivalent to providing the motor with a large excitation current to ensure that the large current open-loop strong push method can ensure that the load leaves the resistance point smoothly.

[0152] As can be seen, in this embodiment, the preset current threshold, the first target current value, the second target current value, and the third target current value can all be based on the peak current that the motor can withstand. That is, the preset current threshold, the first target current value, the second target current value, and the third target current value are all expressed in per-unit value form, rather than using a fixed absolute value. Based on this, the method provided in this embodiment can be decoupled from the motor characteristics, thereby improving the applicability of the method provided in this embodiment to different motors.

[0153] In one exemplary embodiment, the method further includes:

[0154] Noise current is collected when no current flows through a three-phase full-bridge circuit.

[0155] Based on the noise current and the current margin, a preset current threshold is determined.

[0156] In this context, "no current flows through the three-phase full-bridge circuit" can refer to either the motor controller not being in operation or the switching devices in the three-phase full-bridge circuit being turned off.

[0157] Noise current refers to the current generated by the background noise in a three-phase full-bridge circuit when no current flows through it.

[0158] Optionally, the noise current can be acquired by the controller from the three-phase full-bridge circuit via the ADC module.

[0159] The time point for collecting noise current should be a time point before the time point for detecting whether the load needs to move away from the resistance point.

[0160] Optionally, the current margin can be preset manually.

[0161] Optionally, the current margin can be a current value of 0.01A, 0.02A, 0.03A, or other values.

[0162] Optionally, the preset current threshold can be determined based on the sum of the noise current and the current margin.

[0163] In this embodiment, the preset current threshold is determined based on the noise current and the current margin. Therefore, since the preset current threshold takes into account the existence of the noise current in the three-phase full-bridge circuit, the preset current threshold has high accuracy and reliability. Thus, based on the preset current threshold, it can be accurately ensured that the three-phase current has indeed been discharged completely before the switching devices of the three-phase full-bridge circuit are turned on again, thereby improving the reliability of the FOC closed-loop process.

[0164] In an exemplary embodiment, determining the preset current threshold based on the noise current and the current margin includes:

[0165] The preset current threshold is determined based on noise current, current margin, and temperature compensation.

[0166] Optionally, the motor may be equipped with an on-chip temperature sensor, so that the temperature compensation amount can be determined by the controller through the temperature value collected by the on-chip temperature sensor.

[0167] It can be determined by the temperature of the sampling resistor in the three-phase full-bridge circuit and the temperature drift of the operational amplifier in the controller.

[0168] Alternatively, the preset current threshold can be determined based on the production line self-learning of the load. During the calibration phase, different near-zero current thresholds are scanned, and the minimum current threshold and production line current margin that enable the current-type observer to converge reliably are recorded. The sum of this minimum current threshold and the production line current margin is then used as the preset current threshold.

[0169] In an exemplary embodiment, when the amplitudes of the three-phase currents in the three-phase full-bridge circuit are all less than or equal to a preset current threshold, turning on the switching devices in the three-phase full-bridge circuit and increasing the excitation current reference value to the first target current value includes:

[0170] Determine the actual bus voltage;

[0171] The dynamic scaling value for the preset current threshold is determined based on the actual bus voltage;

[0172] The preset current threshold is scaled based on the dynamic scaling value to obtain the scaled current threshold.

[0173] When the amplitudes of the three-phase currents in the three-phase full-bridge circuit are all less than or equal to the scaled current threshold, the switching devices in the three-phase full-bridge circuit are turned on, and the excitation current reference value is increased to the first target current value.

[0174] Optionally, when the scaled current threshold is the product of the dynamic scaling value and the preset current threshold, the actual bus voltage and the dynamic scaling value can be positively correlated.

[0175] In this embodiment, the dynamic scaling value is determined by the actual bus voltage, and the preset current threshold is scaled based on the dynamic scaling value. Based on the scaled current threshold, the conduction time of the switching devices in the three-phase full-bridge circuit can be made more accurate and reliable, further ensuring the reliability of the smooth switching from open loop to FOC closed loop.

[0176] In one exemplary embodiment, the load is the windshield wiper, and the resistance point is the location of the wiper outlet.

[0177] In the case of concealed / pop-up windshield wipers, the wipers are hidden inside the vehicle trim panel when not in use. Based on this, the location of the wiper outlet can be understood as the position where the trim panel is popped open by the wiper. That is to say, the location of the wiper outlet can be understood as the position where the wiper pops out, that is, the position where the wiper appears on the working surface when it switches from the concealed state to the non-concealed state.

[0178] In one exemplary embodiment, the load being executed is a pump or a valve, and the resistance point is a self-locking point or a mechanical jamming point of the load being executed.

[0179] It should be noted that this embodiment does not limit the specific type of the execution load. As long as the resistance point is the location where the execution load needs to be excited by a large current to break the mechanical jamming or mechanical stall phenomenon, and the execution load needs to seamlessly switch the FOC closed loop after leaving the resistance point, the method provided in this embodiment can be applied. That is to say, the method provided in this embodiment has a wide range of applicability.

[0180] The application process of the above-mentioned excitation current control method will be illustrated below with a detailed embodiment, such as... Figure 3 As shown, the details are as follows:

[0181] Step 302: When it is detected that the load needs to be removed from the resistance point, the motor is supplied with a current corresponding to the third target current value through the three-phase full-bridge circuit to instruct the motor to work under the current of the third target current value so as to drive the load to move in the set direction.

[0182] Step 304: If the Hall output value of the Hall sensor is collected, determine that the load has moved away from the resistance point.

[0183] Step 306: After determining that the load has moved away from the resistance point, the switching devices in the three-phase full-bridge circuit are turned off by stopping the transmission of electrical signals to the pre-drive chip.

[0184] Step 308: When the amplitude of the three-phase current in the three-phase full-bridge circuit is less than or equal to the preset current threshold, the switching devices in the three-phase full-bridge circuit are turned on by re-sending an electrical signal to the pre-drive chip, and the excitation current reference value is increased to the first target current value.

[0185] Step 310: Determine the actual excitation current based on the voltage across the sampling resistor in the three-phase full-bridge circuit and the resistance value of the sampling resistor.

[0186] Step 312: If the actual excitation current is detected to reach the first target current value, it means that the angle difference between the estimated electrical angle of the motor rotor by the current-type observer and the actual angle of the motor rotor is less than or equal to the angle difference threshold. The excitation current reference value is then reduced from the first target current value to the second target current value.

[0187] In this embodiment, firstly, after the load moves along the set direction and leaves the resistance point by a large open-loop push with a current corresponding to the third target current value, the load is first discharged through the time window corresponding to the time window after the switching devices in the three-phase full-bridge circuit are turned off, so that the three-phase current decays to near zero to reset the electrical transient. Then, the excitation current reference value is raised to the first target current value so that the current-type observer can re-converge the estimated electrical angle and then realize the FOC closed loop. Based on this, the undesirable phenomena such as motor step loss, vibration, and abnormal noise caused by forcibly entering the FOC closed loop before the estimated electrical angle has converged are eliminated.

[0188] In this embodiment, the second aspect is that it is neither necessary nor possible to make the open-loop command angle and the estimated electrical angle continuous, that is, it is not necessary to rely on smooth drag and gradual handshake. Instead, a "current zero reset mechanism" ensured by a preset current threshold and a "current fast relock mechanism" that increases the excitation current reference value to the first target current value are used to deal with severe high current transients, so that the process of FOC re-entering closed-loop control is invisible to the user's naked eye.

[0189] In this embodiment, the third aspect is that the discharge time window is determined by the fact that the amplitude of all three phase currents is less than or equal to a preset current threshold. At the same time, the current-type observer is also determined by the fact that the actual excitation current reaches the first target current value to estimate the completion of electrical angle convergence. Based on this, since both the end of discharge and the estimated electrical angle convergence are determined by the measured current value, the method provided in this embodiment can adapt to the mechanical and power supply discreteness of different execution loads and can be stably implemented on multiple different execution loads. By covering batch consistency, the production yield of the excitation current control system using the method provided in this embodiment is improved.

[0190] In this embodiment, the fourth aspect is that by increasing the excitation current reference value to the first target current value, the actual excitation current transient is raised to provide current excitation to the current-type observer, which accelerates the convergence of the current-type observer for estimating the electrical angle, so that after a large current open-loop push, it can quickly, smoothly, and without jolts switch to the FOC closed loop, meeting the user's requirements for the smoothness of the execution load's motion.

[0191] In this embodiment, the fifth aspect is that the method provided in this embodiment only needs to reuse the current sampling capability of a typical motor controller and the pre-drive switching capability for the switching devices in a three-phase full-bridge circuit. That is to say, the method provided in this embodiment can be implemented based on pure software timing control without additional hardware costs, which is conducive to the commercialization of the excitation current control system using the method provided in this embodiment.

[0192] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0193] Based on the same inventive concept, this application also provides an excitation current control device for implementing the excitation current control method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the excitation current control device provided below can be found in the limitations of the excitation current control method described above, and will not be repeated here.

[0194] In one exemplary embodiment, such as Figure 1 As shown, an excitation current control system 100 is also provided. The system includes an execution load 104, a motor 106 and a controller 102. The controller 102 includes a three-phase full-bridge circuit 1022, which is connected to the motor 106. The motor 106 is connected to the execution load 104.

[0195] The controller 102 is used to implement the steps of any of the above embodiments of the excitation current control method.

[0196] In one exemplary embodiment, such as Figure 4 As shown, a vehicle 400 is also provided, which includes an excitation current control system 100 as described in any of the above embodiments of the excitation current control system.

[0197] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows: Figure 5As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores data related to the excitation current control method. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external devices via a network connection. When the computer program is executed by the processor, it implements an excitation current control method.

[0198] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0199] In one exemplary embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0200] In one exemplary embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above-described method embodiments.

[0201] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0202] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0203] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0204] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for controlling excitation current, characterized in that, The method includes: When it is detected that the load has moved away from the resistance point, the switching devices in the three-phase full-bridge circuit are turned off. When the amplitude of the three-phase current in the three-phase full-bridge circuit is less than or equal to the preset current threshold, the switching device in the three-phase full-bridge circuit is turned on, and the excitation current reference value is increased to the first target current value. The actual excitation current is determined based on the voltage across the sampling resistor and the resistance value of the sampling resistor in the three-phase full-bridge circuit. If the actual excitation current is detected to reach the first target current value, it means that the angle difference between the estimated electrical angle of the motor rotor by the current-type observer and the actual angle of the motor rotor is less than or equal to the angle difference threshold, and the excitation current reference value is reduced from the first target current value to the second target current value.

2. The method according to claim 1, characterized in that, The method further includes: When it is detected that the load needs to be removed from the resistance point, the three-phase full-bridge circuit provides the motor with a current corresponding to the third target current value, so as to instruct the motor to work under the current of the third target current value, so as to drive the load to move in a set direction, and the resistance point is located in the set direction.

3. The method according to claim 1, characterized in that, A Hall sensor element is provided at the location of the resistance point of the applied load; The step of turning off the switching devices in the three-phase full-bridge circuit when it is detected that the load has moved away from the resistance point includes: If the Hall output value of the Hall sensor is collected, it is determined that the load has moved away from the resistance point; After determining that the load has moved away from the resistance point, the switching devices in the three-phase full-bridge circuit are turned off.

4. The method according to claim 1, characterized in that, The three-phase full-bridge circuit is connected to the pre-drive chip; The switching devices in the three-phase full-bridge circuit that are turned off include: By stopping the transmission of electrical signals to the pre-drive chip, the switching devices in the three-phase full-bridge circuit are turned off. The switching device that enables the three-phase full-bridge circuit includes: By re-sending an electrical signal to the pre-drive chip, the switching devices in the three-phase full-bridge circuit are turned on.

5. The method according to claim 1, characterized in that, The magnitude of the first target current value is 2 to 3 times the magnitude of the second target current value.

6. The method according to claim 1, characterized in that, If the actual excitation current is detected to have reached the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value, including: Detect the motor rotor speed and actual excitation current; When the motor rotor speed is within a preset speed range and the actual excitation current increases to the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value; or, Detect torque current and actual excitation current; When the torque current is within a preset current range and the actual excitation current increases to the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value; or, Detect the motor rotor speed, torque current, and actual excitation current; When the motor rotor speed is within a preset speed range, the torque current is within a preset current range, and the actual excitation current increases to the first target current value, the excitation current reference value is reduced from the first target current value to the second target current value.

7. The method according to claim 1, characterized in that, The method further includes: When no current flows through the three-phase full-bridge circuit, the noise current is collected; The preset current threshold is determined based on the noise current and the current margin.

8. The method according to claim 7, characterized in that, Determining the preset current threshold based on the noise current and the current margin includes: The preset current threshold is determined based on the noise current, the current margin, and the temperature compensation.

9. The method according to claim 1, characterized in that, When the amplitudes of the three-phase currents in the three-phase full-bridge circuit are all less than or equal to a preset current threshold, the switching devices in the three-phase full-bridge circuit are turned on, and the excitation current reference value is increased to the first target current value, including: Determine the actual bus voltage; A dynamic scaling value for the preset current threshold is determined based on the actual bus voltage; The preset current threshold is scaled based on the dynamic scaling value to obtain the scaled current threshold. When the amplitudes of the three-phase currents in the three-phase full-bridge circuit are all less than or equal to the scaled current threshold, the switching devices in the three-phase full-bridge circuit are turned on, and the excitation current reference value is increased to the first target current value.

10. The method according to claim 1, characterized in that, The load being executed is the windshield wiper, and the resistance point is the location of the wiper outlet.

11. An excitation current control system, characterized in that, The system includes an execution load, a motor, and a controller. The controller includes a three-phase full-bridge circuit, which is connected to the motor, and the motor is connected to the execution load. The controller is used to implement the steps of the method according to any one of claims 1 to 10.

12. A vehicle, characterized in that, The vehicle includes the excitation current control system as described in claim 11.

13. A computer device, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method according to any one of claims 1 to 10.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 10.

15. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 10.

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