System and method for managing stall conditions in electromechanical braking

Abstract

This disclosure relates to systems and methods for managing stall conditions in electromechanical braking. A method for controlling an electromechanical braking (EMB) unit of a vehicle includes: detecting a stall condition of the motor of the EMB unit; determining a modified current command based on an initial current command to generate a balanced sinusoidal phase current during the stall condition; determining a compensation voltage command in response to detecting the stall condition of the motor and based on the modified current command; and commanding an inverter to apply an output voltage to the motor based on the compensation voltage command, thereby generating a balanced sinusoidal phase current in the windings of the motor during the stall condition while maintaining the clamping force generated by the EMB unit.

Description

Technical Field

[0001] This disclosure relates to braking systems, and more specifically, to systems and methods for controlling electromechanical braking units in vehicles. Background Technology

[0002] Vehicles (such as cars, trucks, SUVs, crossovers, vans, ships, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transport) typically include a braking system. This braking system generally controls various aspects of the vehicle's braking, including providing braking assistance to the operator, anti-lock braking system (ABS) activation, traction control, etc.

[0003] In some braking systems, braking demand may persist for extended periods during specific operating conditions. This prolonged braking demand places thermal and control-related stresses on the components used to generate and maintain braking force. These stresses may vary based on the commanded braking level, the duration of the braking demand, and the vehicle's operating environment.

[0004] However, reducing brake output to address thermal stress can affect the braking system's ability to maintain the requested braking force. Therefore, improved control techniques are needed to manage prolonged braking operations while maintaining braking performance. Summary of the Invention

[0005] This disclosure generally relates to electromechanical braking (EMB) systems for vehicles such as buses and trucks.

[0006] One aspect of the disclosed embodiments includes a method for controlling an electromechanical braking unit in a vehicle. The method includes: detecting a stall condition of the motor of the electromechanical braking unit; determining a modified current command based on an initial current command to generate a balanced sinusoidal phase current during the stall condition; determining a compensation voltage command in response to detecting the stall condition of the motor and based on the modified current command; and commanding an inverter to apply an output voltage to the motor based on the compensation voltage command, thereby generating a balanced sinusoidal phase current in the windings of the motor during the stall condition while maintaining the clamping force generated by the electromechanical braking unit.

[0007] One aspect of the disclosed embodiments includes a braking system for a vehicle. The braking system includes: an electromechanical braking unit including an inverter operatively coupled to a motor and configured to generate a clamping force; and a controller. The controller is configured to: detect a stall condition of the motor; determine a modified current command based on an initial current command to generate a balanced sinusoidal phase current during the stall condition; determine a compensation voltage command in response to detecting the stall condition of the motor and based on the modified current command; and command the inverter to apply an output voltage to the motor based on the compensation voltage command, thereby generating a balanced sinusoidal phase current in the windings of the motor during the stall condition while maintaining the clamping force generated by the electromechanical braking unit.

[0008] These and other aspects of this disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying drawings. Attached Figure Description

[0009] This disclosure is best understood by reading in conjunction with the accompanying drawings and through the following detailed description. It should be emphasized that, by convention, the various features in the drawings are not drawn to scale. Instead, for clarity, the dimensions of the various features have been arbitrarily enlarged or reduced.

[0010] Figure 1 A schematic block diagram of a braking system in a vehicle according to the principles of this disclosure is shown.

[0011] Figure 2 A schematic block diagram of an electromechanical braking unit (EMB) according to the principles of this disclosure is shown.

[0012] Figure 3 A schematic diagram of the braking mechanism of the EMB unit according to the principles of this disclosure is shown.

[0013] Figure 4 A diagram illustrating the principles of this disclosure shows the three-phase current of the motor in the EMB unit after a stall condition.

[0014] Figure 5 A diagram illustrating the principles of this disclosure is shown, illustrating the three-phase current of the motor in the EMB unit before q-axis current adjustment.

[0015] Figure 6 A diagram illustrating the principles of this disclosure is shown, illustrating the three-phase current of the motor in the EMB unit after q-axis current adjustment.

[0016] Figure 7 A flowchart according to one aspect of this disclosure is shown, illustrating a first method for selectively enabling and disabling EMB motor stall control technology.

[0017] Figure 8A schematic block diagram of a controller for an electromechanical braking unit according to one aspect of this disclosure is shown.

[0018] Figure 9 A schematic diagram of a three-phase inverter according to one aspect of this disclosure is shown.

[0019] Figures 10A to 10B A flowchart according to one aspect of this disclosure is shown, which outlines the steps in a second method for controlling an electromechanical braking (EMB) unit in a vehicle. Detailed Implementation

[0020] The following discussion pertains to various embodiments of this disclosure. While one or more of these embodiments may be preferred, the disclosed embodiments should not be construed as or otherwise used to limit the scope of this disclosure, including the claims. Furthermore, those skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is intended only as an illustrative discussion of that embodiment and not to imply that the scope of this disclosure, including the claims, is limited to that embodiment.

[0021] Figure 1 A vehicle 12 based on the principles of this disclosure is generally shown. Vehicle 12 includes four wheels 14 and may include any suitable vehicle, such as a car, truck, SUV, minivan, crossover, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. Although vehicle 12 is illustrated as a passenger vehicle with wheels 14 and used on a road, the principles of this disclosure can be applied to other vehicles, such as airplanes, ships, trains, drones, or other suitable vehicles.

[0022] Figure 1A schematic block diagram of a braking system 10 in a vehicle 12 is shown. The braking system 10 can represent an EMB system with a conventional design. The braking system 10 includes four electromechanical braking units (EBUs) 20a, 20b, 20c, and 20d. EBUs 20a, 20b, 20c, and 20d include: a right front (FR) EBU 20a, a left front (FL) EBU 20b, a right rear EBU 20c, and a left rear EBU 20d. Each of the EBUs 20a, 20b, 20c, and 20d is configured to apply braking force to the corresponding wheel in the wheel 14. The braking system 10 also includes a first brake pedal assembly 22 having a brake pedal 21 actuated by the operator of the vehicle 12. The first brake pedal assembly 22 generates two independent brake actuation signals 26a and 26b, which respectively represent the actuation intensity of the brake pedal 21. Brake actuation signals 26a and 26b can indicate the position of brake pedal 21 or the amount of force applied to brake pedal 21. However, brake actuation signals 26a and 26b can also indicate another related parameter, such as the hydraulic fluid pressure in the brake circuit coupled to brake pedal 21.

[0023] The braking system 10 also includes dual integrated braking units (IBUs) 24a and 24b, each including a first IBU 24a and a second IBU 24b electrically isolated from the first IBU 24a for redundancy. The first IBU 24a is configured to receive a first brake actuation signal 26a from the first brake pedal assembly 22 and transmit a first brake communication signal to each of the EBUs 20a, 20b, 20c, and 20d via a first communication network 28a, thereby causing each of the EBUs 20a, 20b, 20c, and 20d to apply a corresponding braking force to slow down the vehicle. The second IBU 24b is configured to receive a second brake actuation signal 26b from the first brake pedal assembly 22 and transmit a second brake communication signal to each of the EBUs 20a, 20b, 20c, and 20d via the second communication network 28b, thereby causing each of the EBUs 20a, 20b, 20c, and 20d to apply a corresponding braking force to slow down the vehicle. The first communication network 28a and the second communication network 28b may each use a Controller Area Network (CAN) architecture (also known as a CAN bus). However, either or both of the first communication network 28a and / or the second communication network 28b may include different communication architectures, such as Local Interconnect Network (LIN), Ethernet, FlexRay, Data Distribution Service (DDS), or other hardware and / or software standards.

[0024] Figure 2 A schematic block diagram of EMB unit 50 is shown. Figure 2The EMB unit 50 shown can be used for any one or all of the EBUs 20a, 20b, 20c, and 20d in the braking system 10. As shown, the EMB unit 50 includes a first CAN interface 60 for communicating with the first IBU 24a via a first communication network 28a. The EMB unit 50 also includes a second CAN interface 62 for communicating with the second IBU 24b via a second communication network 28b. Therefore, the first CAN interface 60 and the second CAN interface 62 provide bidirectional redundancy to ensure that braking command signals can be transmitted even in the event of a failure of a single component.

[0025] EMB unit 50 also includes a processor 52 coupled to storage memory 54. Processor 52 is also functionally connected to each of the first CAN interface 60 and the second CAN interface 62 to monitor braking communication signals. Storage memory 54 stores instructions, such as program code executed by processor 52, in instruction storage 56. Storage memory 54 also includes data storage 58 for storing data to be used by processor 52. Data storage 58 may record, for example, values ​​of parameters conveyed to processor 52 and / or results of functions calculated by processor 52.

[0026] EMB unit 50 also includes a motor driver 70 coupled to electric motor 72 and braking mechanism 74. Processor 52 will send the final torque command. The power is transmitted to the motor driver 70 to supply power to the electric motor 72, thereby causing the electric motor 72 to generate a corresponding output torque for actuating the braking mechanism 74. However, the processor 52 can transmit different commands (such as voltage commands or current commands) for controlling the electric motor 72, which have different actual clamping forces that cause the electric motor 72 to actuate the braking mechanism 74 to generate braking forces of varying strengths for controlling the vehicle 12. A similar effect.

[0027] The braking mechanism 74 may include, for example, a caliper configured to clamp the rotor between a pair of brake pads. Alternatively, the braking mechanism 74 may include one or more brake shoes that expand to engage the inner surface of the brake drum. The motor driver 70 may include, for example, an inverter or H-bridge, for supplying alternating current (AC) or direct current (DC) power to the electric motor 72 to cause the electric motor 72 to apply an actual clamping force in the braking mechanism 74. This causes vehicle 12 to slow down. Actual clamping force This can describe the force applied by the paired brake pads to clamp the rotor. Alternatively or additionally, the actual clamping force... This can describe the force applied by one or more brake shoes to engage the inner surface of the brake drum. The processor 52 can be programmed or otherwise configured to change the actual clamping force. To match the requested clamping force Request clamping force The clamping force can be determined by the dual integrated braking units (IBU) 24a, 24b based on the actuation strength of the brake pedal 21. It can be determined by another source and / or for another purpose (such as for traction control or torque vectoring).

[0028] EMB unit 50 also includes a function for sensing the actual clamping force applied by braking mechanism 74. The force sensor 76 may include, for example, a load cell or a pressure sensor, for measuring an indication of the actual clamping force applied by the braking mechanism 74. The physical characteristics of the force sensor 76. The force sensor 76 transmits a signal to the processor 52, which is related to the actual clamping force measured by the force sensor 76. Relevant. The force sensor 76 can be integrated into the EMB unit 50, such as... Figure 2 As shown. Alternatively, the force sensor 76 may be located outside the EMB unit 50 and functionally connected to the EMB unit 50.

[0029] The EMB unit 50 also includes a motor position sensor 78 for sensing the rotational position of the electric motor 72. The motor position sensor 78 generates a motor position signal θ representing the angular position of the motor shaft 73 of the electric motor 72. m And then transmit it to processor 52.

[0030] Figure 3 A schematic diagram of the braking mechanism 74 of the EMB unit 50 is shown. As shown, the electric motor 72 includes a motor shaft 73 connected to a gearbox 80. The gearbox 80 rotates the output shaft 82 by rotating the motor shaft 73 and provides gear reduction between the motor shaft 73 and the output shaft 82. Therefore, the gearbox 80 is used to increase torque while reducing angular velocity. The braking mechanism 74 also includes a ball screw 84 with multiple ball bearings configured to convert the rotation of the output shaft 82 into linear motion of a piston 86. The piston 86 then applies the actual clamping force. An application is made to the friction plate 88 to bias it against the rotor 90, which is configured to rotate together with a corresponding one of the four wheels 14. The braking mechanism 74 also includes a caliper 92 that mechanically connects the fixed portion of the ball screw 84 to another friction plate 88 opposite the piston 86.

[0031] As shown, the braking mechanism 74 also includes a brake position sensor 98 configured to measure the position Pos. of the piston 86. The brake position sensor 98 transmits a signal indicating the measured position Pos. of the piston 86 to the processor 52. The brake position sensor 98 can measure the position Pos. of the piston 86 directly, for example, using a linear encoder or potentiometer. Alternatively, the brake position sensor 98 can measure the position Pos. of the piston 86 indirectly, for example, by measuring the rotational position of the motor shaft 73 or the output shaft 82.

[0032] EMB unit 50 uses electric motor 72 to generate motor torque, thereby providing clamping force control. Gearbox 80 and ball screw 84 convert the rotation of motor shaft 73 into displacement of piston 86.

[0033] Figure 4 A graph is shown illustrating the three-phase current of the motor in the EMB unit after stall conditions, using d-axis current tuning as explained in equation (1): (1) in, It is the q-axis component of the initial current command. It is the adjustment coefficient. It is a predetermined reference frequency, and It's time. From Figure 4 The results show that dynamic adjustment of the current phase has been achieved.

[0034] Pure d-axis current cannot achieve current phase adjustment at different stall positions. At the stall position θ = π / 6 rad, the B-phase current phase cannot be adjusted. Therefore, q-axis current adjustment may be necessary to achieve current phase adjustment for all stall positions. Figure 5 A diagram illustrating the principles of this disclosure is shown, illustrating the three-phase current of the motor in the EMB unit before q-axis current adjustment. Figure 6 A diagram illustrating the principles of this disclosure is shown, illustrating the three-phase current of the motor in the EMB unit after q-axis current adjustment.

[0035] Equation (2) below describes the q-axis compensation current ( The calculation of ), while equation (3) describes the calculation of the q-axis compensation current ( Determine the adjusted q-axis current ( Calculation of ) (2) (3) in, It is the q-axis component of the initial current command. and It is a calibration value. It is a predetermined reference frequency, and It's time.

[0036] Figure 7 A flowchart according to one aspect of this disclosure is shown, illustrating a first method 100 for selectively enabling and disabling EMB motor stall control technology. The first method 100 begins at 102 and includes determining a stall speed trigger at step 104. For example, step 104 may include determining that the angular velocity of the electric motor 72 is less than a predetermined threshold speed (such as 3.0 radians per second). However, the predetermined threshold speed may have another value. Alternatively or additionally, step 104 may include measuring another relevant parameter, such as the angular velocity of the output shaft 82 or the change in the position Pos. of the piston 86 (as measured by the brake position sensor 98). This may be based on the motor position signal θ from the motor position sensor 78. m The angular velocity of the motor can be determined using one or more other techniques or sources.

[0037] The first method 100 further includes determining at step 110 that a first stall criterion is met. Step 110 may include determining that the motor torque command is higher than a first torque threshold. For example, step 110 may include determining that the motor torque command is greater than 1.0 Nm. Additionally or alternatively, step 110 may include determining that the clamping force is higher than a first force threshold. For example, step 110 may include determining that the actual or commanded value of the clamping force is greater than 20 kN. However, it should be understood that these are merely examples, and other values ​​may be used for any one or both of the first torque threshold and / or the first force threshold.

[0038] The first method 100 further includes determining at step 112 that a first blocking criterion is continuously met for a first predetermined time period. For example, step 112 may include determining that the first blocking criterion determined at step 110 is maintained for a first predetermined time period. The first predetermined time period may be, for example, 10 seconds (10s). However, the first predetermined time period may be a different amount of time.

[0039] The first method 100 further includes determining at step 114 that a second stall criterion is met. Step 114 may include determining that the motor torque command is higher than a second torque threshold, which is greater than a first torque threshold. For example, step 114 may include determining that the motor torque command is greater than 1.5 Nm. Additionally or alternatively, step 114 may include determining that the clamping force is higher than a second force threshold, which is greater than the first force threshold. For example, step 114 may include determining that the actual or commanded value of the clamping force is greater than 30 kN. However, it should be understood that these are merely examples, and other values ​​may be used for any one or both of the second torque threshold and / or the second force threshold.

[0040] The first method 100 further includes determining at step 116 that a second stall criterion is continuously met for a second predetermined time period. For example, step 116 may include determining that the second stall criterion determined at step 114 is maintained for a second predetermined time period, which is shorter than a first predetermined time period. The second predetermined time period may be, for example, 5 seconds (5s). However, the second predetermined time period may be a different amount of time.

[0041] The first method 100 further includes confirming the stall condition of the motor at step 120. Step 120 may include determining that a first stall criterion is continuously met during a first predetermined time period, or that a second stall criterion is continuously met during a second predetermined time period. For example, step 120 is confirmed in response to either step 112 or 114 determining that the corresponding stall criterion is continuously met during the associated predetermined time period.

[0042] The first method 100 further includes setting a stall control enable flag at step 122. Step 122 may selectively enable the stall control technology of this disclosure in response to confirmation of a stall condition at step 120. Alternatively, step 122 may selectively disable the stall control technology of this disclosure in response to the stall speed trigger no longer being met. For example, step 122 may selectively disable the stall control technology in response to step 104 determining that the angular velocity of the electric motor 72 is not less than a predetermined threshold speed. Step 122 may include selectively setting one or more bits or values ​​in a machine-readable storage memory. Alternatively, step 122 may utilize other techniques, such as selectively executing one or more program functions in response to confirmation of a stall condition, to implement the stall control technology of this disclosure.

[0043] Figure 8 A schematic block diagram of a controller 150 for an electromechanical braking unit according to one aspect of this disclosure is shown. The controller 150 may be implemented in hardware and / or software. In some embodiments, various functions of the controller 150 may be implemented by software instructions executed by a processor 52.

[0044] Controller 150 will send initial current command i d_cmd , i q_cmd As input, the initial current command includes the d-axis current command component. i d_cmd and q-axis current command component i q_cmd The initial current command can be calculated based on the torque command. i d_cmd , i q_cmd This is so that the electric motor 72 generates torque according to the torque command. However, this aspect is not in Figure 8 As shown in the image.

[0045] Controller 150 includes current controller 152, which is based on an initial current command. i d_cmd , i q_cmd Generate initial voltage command U dref U qref Initial voltage command U dref U qref Including the d-axis voltage reference signal U dref and q-axis voltage reference signal U qref The current controller 152 further bases its signal on a feedback current signal I that describes the actual current supplied to the electric motor 72. d_fb I q_fb Generate initial voltage command U dref U qref Feedback current signal I d_fb I q_fb Including d-axis feedback current I d_fb and q-axis feedback current I q_fb The current controller 152 can use a control loop (such as a proportional-integral (PI) or proportional-integral-derivative (PID) control loop) to generate the voltage reference signal U. dref and q-axis voltage reference signal U qref .

[0046] The controller 150 also includes a voltage compensator 154, which generates an initial voltage command U. dref U qref The final voltage command 155 is the sum of the compensation voltage commands 183 and 184. In some embodiments, the final voltage command 155 may include d-axis and q-axis components. However, the final voltage command 155 may take other forms.

[0047] Controller 150 also includes a field-oriented controller 156, which implements a field-oriented control strategy to generate a modulation index signal based on the final voltage command 155. mi And the phase lead angle signal δ. Controller 150 also includes a space vector pulse width modulation (SVPWM) controller 158, which is based on a modulation index signal from the field orientation controller 156. mi The phase lead angle signal δ generates multiple pulse width modulation (PWM) signals 159. The controller 150 also includes an inverter 160, which may include two or more solid-state switches controlled by the PWM signals 159 to selectively conduct current, thereby applying an output voltage to the windings of the electric motor 72. The inverter 160 and the electric motor 72 may each be a multiphase device with three or more phases.

[0048] The controller 150 also includes a current sensor 96, which measures the three-phase current of the current conducted between the inverter 160 and the electric motor 72. Ia, Ib, Ic The controller 150 also includes a current converter 97, which is based on the three-phase current measured by the current sensor 96. Ia, Ib, Ic Determine the feedback current signal I d_fb I q_fb The current converter 97 can employ Clarke transform and / or Park transform, and can use additional information such as the motor position signal θ from the motor position sensor 78. m In order to determine the feedback current signal I d_fb I q_fb .

[0049] The controller 150 also includes a stall trigger 170 that determines a stall condition in the electric motor 72 and generates a stall signal 171 indicating the stall condition. The stall trigger 170 can implement the first method 100 described above. However, the stall trigger 170 can use other techniques to selectively generate the stall signal 171 indicating the stall condition.

[0050] The controller 150 also includes a current phase adjuster 180, which is based on a predetermined reference frequency. And based on the initial current command i d_cmd , i q_cmd q-axis components To generate modified current commands id , iq The current phase regulator 180 can selectively generate a modified current command in response to receiving a stall signal 171 indicating a stall condition. id , iq The current phase adjuster 180 can generate a modified current command according to the above equations (1)-(3). id , iq However, other techniques can be used. The controller 150 also includes a regulating voltage generator 182, which is based on a modified current command. id , iq Generate compensation voltage command 183. Adjust voltage generator 182 can be configured to base on modified current command. id , iq The corresponding d-axis and q-axis components are used to calculate the d-axis and q-axis components of the compensation voltage command 183.

[0051] Figure 9 A schematic diagram of an inverter 160 according to one aspect of this disclosure is shown. The inverter 160 is a three-phase design configured to generate AC power on a group of three-phase leads 162 to supply power to an electric motor 72. The inverter 160 includes a DC source 190 providing DC voltage across DC buses 192p and 192n. DC buses 192p and 192n include a positive conductor 192p and a negative conductor 192n. A group of A-phase switches U_H and U_L are operable to selectively connect either the positive conductor 192p or the negative conductor 192n to the A-phase conductor of the three-phase leads 162. A group of B-phase switches V_H and V_L are operable to selectively connect either the positive conductor 192p or the negative conductor 192n to the B-phase conductor of the three-phase leads 162. The grouped C-phase switches W_H and W_L are operable to selectively connect either the positive conductor 192p or the negative conductor 192n to the C-phase conductor of the three-phase lead 162. Each of the grouped switches U_H and U_L, V_H and V_L, and W_H and W_L includes a high-side switch (as indicated by "H") and a low-side switch (as indicated by "L"), and can be selectively controlled by a PWM signal 159. Each of the switches U_H, U_L, V_H, V_L, W_H, and W_L can be implemented using a metal-oxide-semiconductor field-effect transistor (MOSFET) device. However, other types of switching devices can be used, such as insulated-gate bipolar transistors (IGBTs) or other types of field-effect transistors (FETs), such as gallium nitride high electron mobility transistors (GaN HEMTs) or silicon carbide (SiC) transistor devices.

[0052] The technology disclosed herein provides several advantages for stall mode operation. It has been shown that the technology of this disclosure significantly reduces the temperature of the solid-state switching devices used to implement the switches U_H, U_L, V_H, V_L, W_H, W_L in the inverter 160, thereby allowing continuous operation under stall conditions with minimal impact on the output torque.

[0053] Table 1 below shows the temperature rise (°C) of switches U_H, U_L, V_H, V_L, W_H, W_L in inverter 160 for an electric motor 72 stalled at the first corner position for three different torque command values, without a modified current command and with a modified current command as determined according to this disclosure. Table 1

[0054] Table 2 below shows the temperature rise (°C) of switches U_H, U_L, V_H, V_L, W_H, W_L in inverter 160 for an electric motor 72 stalled at the second corner position for three different torque command values, without a modified current command and with a modified current command as determined according to this disclosure. Table 2

[0055] Table 3 below shows the temperature rise (°C) of switches U_H, U_L, V_H, V_L, W_H, W_L in inverter 160 for an electric motor 72 stalled at the third triangular position for three different torque command values, without a modified current command and with a modified current command as determined according to this disclosure. Table 3

[0056] Tables 1-3 show that the modified current commands generated by the systems and methods of this disclosure provide significantly reduced temperatures and / or significantly increased rise times for a given temperature rise constraint. These increased rise times can be advantageously used to provide a longer duration of stall conditions for the EMB system while maintaining a given clamping force.

[0057] Table 4 below shows the difference in possible stall duration for a given temperature rise constraint on solid-state switching devices in an inverter, with and without the modified current technique (abbreviated as "Mod.Curr.") and with the modified current technique of this disclosure. For a given temperature rise, experimental data show that the system and method of this disclosure significantly extend the stall duration. Table 4

[0058] Table 5 below summarizes the performance of EMBs with and without the modified current technology of this disclosure. Experimental data demonstrate that the system and method of this disclosure have minimal impact on clamping force while significantly reducing the temperature rise of solid-state switching devices in the inverter. Table 5

[0059] Figures 10A to 10B A flowchart according to one aspect of this disclosure is shown, outlining the steps in a second method for controlling an electromechanical braking (EMB) unit of a vehicle. One or more steps of the second method 200 may be performed by an electronic control unit (ECU) (such as one or more of IBUs 24a, 24b, or processor 52). As will be understood from this disclosure, the sequence of operations within the method is not limited to... Figures 10A to 10B The order of execution shown may be performed, but may be performed in one or more different orders as applicable, in accordance with this disclosure.

[0060] The second method 200 includes detecting a stall condition of the motor in the electromechanical braking unit at step 202. Step 202 can be performed, for example, by processor 52 executing program instructions to compare the angular velocity of the electric motor 72 with a predetermined threshold speed (such as 3.0 radians per second). However, the predetermined threshold speed can have other values.

[0061] In some embodiments, step 202 further includes confirming the motor's stall condition based on a timer duration that maintains the torque-related operating value relative to a stall threshold. For example, step 202 may also include processor 52 executing program instructions to implement the first method 100 of this disclosure.

[0062] The second method 200 further includes, at step 204, determining a modified current command based on the initial current command to generate a balanced sinusoidal phase current during stall conditions. Step 204 can, for example, be implemented by processor 52 executing program instructions to implement current phase regulator 180 to generate the modified current command. id , iq To execute.

[0063] In some embodiments, the modified current command may include an adjusted d-axis current command, and step 204 may include determining the adjusted d-axis current command based on the q-axis component and adjustment coefficient of the initial current command. For example, generating the adjusted d-axis current command may include determining the adjusted d-axis current command according to the following formula: ,in, It is the q-axis component of the initial current command. It is the adjustment coefficient. It is a predetermined reference frequency, and It's time.

[0064] In some embodiments, the modified current command may include an adjusted q-axis current command. Step 204 may include, at sub-step 204a, determining a q-axis compensation current based on the q-axis component of the initial current command and multiple calibration values. For example, sub-step 204a may include calculating the q-axis compensation current according to the following formula ( ): ,in, It is the q-axis component of the initial current command. and It is a calibration value. It is a predetermined reference frequency, and It's time.

[0065] Step 204 may further include: at sub-step 204b, combining the q-axis compensation current with the q-axis component of the initial current command. For example, sub-step 204a may include calculating the adjusted q-axis current command according to the following formula ( i q ): .

[0066] The second method 200 further includes confirming the motor's stall condition at step 206 based on a timer duration corresponding to the torque-related operating value relative to the stall threshold. For example, the modified current command and / or the resulting compensated voltage command may be disabled or set to zero unless and until the motor's stall condition is confirmed. In some embodiments, the torque-related operating value is a motor torque command used to determine the initial current command. However, the torque-related operating value may be the actual torque or some other parameter that varies with the motor torque.

[0067] In some embodiments, step 206 includes either: determining at sub-step 206a that a first stall criterion is continuously met for a first predetermined time period; or determining at sub-step 206b that a second stall criterion is continuously met for a second predetermined time period, the second predetermined time period being shorter than the first predetermined time period. The first stall criterion includes a torque-related operating value higher than a first torque threshold. The second stall criterion may include a torque-related operating value higher than a second torque threshold, the second torque threshold being greater than the first torque threshold. In some embodiments, the first stall criterion may further include a clamping force higher than a first force threshold, and the second stall criterion may further include a clamping force higher than a second force threshold, the second force threshold being greater than the first force threshold.

[0068] The second method 200 further includes determining a compensation voltage command based on the modified current command at step 208. Step 208 can, for example, be implemented by executing program instructions via processor 52 based on the modified current command. id , iq The regulating voltage generator 182 executes the compensation voltage command 183.

[0069] In some embodiments, step 208 may be performed in response to confirmation of motor stall. In other words, step 208 may be performed selectively only in response to confirmation of motor stall in step 206. Otherwise, the compensation voltage command may be disabled, such as by being set to zero or some other predetermined default value.

[0070] The second method 200 further includes, at step 210, commanding the inverter to apply the output voltage to the motor based on a compensation voltage command, thereby generating a balanced sinusoidal phase current in the motor windings during a stall condition while maintaining the clamping force generated by the electromechanical braking unit.

[0071] In some embodiments, step 210 includes determining an initial voltage command based on an initial current command at sub-step 210a. Sub-step 210a may, for example, be implemented by processor 52 executing program instructions to enable current controller 152 to perform the initial current command. i d_cmd , i q_cmd Generate initial voltage command U dref U qref To execute.

[0072] In some embodiments, step 210 includes determining the final voltage command at sub-step 210b as the sum of the initial voltage command and the compensation voltage command. Sub-step 210b may, for example, be executed by processor 52 to implement voltage compensator 154 to generate the initial voltage command U. dref U qref The final voltage command 155 is executed by summing the compensation voltage command 183.

[0073] In some embodiments, step 210 further includes commanding the inverter at sub-step 210c based on the final voltage command. Sub-step 210c may be performed, for example, by processor 52 executing program instructions to enable field-oriented controller 156 and SVPWM controller 158 to generate a plurality of PWM signals 159 based on the final voltage command 155 and supply them to inverter 160.

[0074] This disclosure provides a method for controlling an electromechanical braking unit in a vehicle. The method includes: detecting a stall condition of the motor of the electromechanical braking unit; determining a modified current command based on an initial current command to generate a balanced sinusoidal phase current during the stall condition; determining a compensation voltage command in response to detecting the stall condition of the motor and based on the modified current command; and commanding an inverter to apply an output voltage to the motor based on the compensation voltage command, thereby generating a balanced sinusoidal phase current in the windings of the motor during the stall condition while maintaining the clamping force generated by the electromechanical braking unit.

[0075] In some embodiments, the method may further include: determining an initial voltage command based on an initial current command; and determining a final voltage command as the sum of the initial voltage command and a compensation voltage command. In some embodiments, commanding the inverter based on the compensation voltage command includes commanding the inverter to apply an output voltage to the motor based on the final voltage command.

[0076] In some embodiments, the modified current command includes an adjusted d-axis current command, and determining the modified current command includes determining the adjusted d-axis current command based on the q-axis component of the initial current command and an adjustment factor.

[0077] In some embodiments, generating an adjusted d-axis current command includes determining the adjusted d-axis current command according to the following formula: ,in, It is the q-axis component of the initial current command. It is the adjustment coefficient. It is a predetermined reference frequency, and It's time.

[0078] In some embodiments, the modified current command includes an adjusted q-axis current command, and determining the adjusted q-axis current command includes: determining a q-axis compensation current based on the q-axis component of the initial current command and a plurality of calibration values; and combining the q-axis compensation current with the q-axis component of the initial current command.

[0079] In some embodiments, determining the adjusted q-axis current command includes: determining the q-axis compensation current according to the following formula ( ): And determine the adjusted q-axis current command according to the following formula ( i q ): ,in, It is the q-axis component of the initial current command. and It is a calibration value. It is a predetermined reference frequency, and It's time.

[0080] In some embodiments, detecting a stall condition includes comparing the motor's angular velocity with a speed threshold.

[0081] In some embodiments, the method may further include: determining the stall condition of the motor based on a timer duration corresponding to a torque-related operating value relative to a stall threshold, and determining a compensation voltage command based on a modified current command in response to determining the stall condition of the motor.

[0082] In some embodiments, the torque-related operating value is a motor torque command used to determine the initial current command.

[0083] In some embodiments, confirming a stall condition includes any one of the following: determining that a first stall criterion is continuously met for a first predetermined time period; or determining that a second stall criterion is continuously met for a second predetermined time period, the second predetermined time period being shorter than the first predetermined time period. The first stall criterion may include a torque-related operating value higher than a first torque threshold, and the second stall criterion may include a torque-related operating value higher than a second torque threshold, the second torque threshold being greater than the first torque threshold.

[0084] In some embodiments, the first stall criterion further includes a clamping force higher than a first force threshold, and the second stall criterion further includes a clamping force higher than a second force threshold, the second force threshold being greater than the first force threshold.

[0085] One aspect of the disclosed embodiments includes a braking system for a vehicle. The braking system includes: an electromechanical braking unit including an inverter operatively coupled to a motor and configured to generate a clamping force; and a controller. The controller is configured to: detect a stall condition of the motor; determine a modified current command based on an initial current command to generate a balanced sinusoidal phase current during the stall condition; determine a compensation voltage command in response to detecting the stall condition of the motor and based on the modified current command; and command the inverter, based on the compensation voltage command, to apply an output voltage to the motor, thereby generating a balanced sinusoidal phase current in the windings of the motor during the stall condition while maintaining the clamping force generated by the electromechanical braking unit.

[0086] In some embodiments, the controller is further configured to: determine an initial voltage command based on an initial current command; and determine a final voltage command as the sum of the initial voltage command and a compensation voltage command. Commanding the inverter based on the compensation voltage command may include commanding the inverter to apply an output voltage to the motor based on the final voltage command.

[0087] In some embodiments, the modified current command includes an adjusted d-axis current command, and determining the modified current command may include determining the adjusted d-axis current command based on the q-axis component of the initial current command and an adjustment factor.

[0088] In some embodiments, generating an adjusted d-axis current command includes determining the adjusted d-axis current command according to the following formula: ,in, It is the q-axis component of the initial current command. It is the adjustment coefficient. It is the predetermined reference frequency, and It's time.

[0089] In some embodiments, the modified current command includes an adjusted q-axis current command, and determining the adjusted q-axis current command includes: determining a q-axis compensation current based on the q-axis component of the initial current command and a plurality of calibration values; and combining the q-axis compensation current with the q-axis component of the initial current command.

[0090] In some embodiments, determining the adjusted q-axis current command includes:

[0091] The q-axis compensation current is determined according to the following formula ( ): And determine the adjusted q-axis current command according to the following formula ( i q ): ,in, It is the q-axis component of the initial current command. and It is a calibration value. It is a predetermined reference frequency, and It's time.

[0092] In some embodiments, detecting a stall condition includes determining that the motor speed is less than a speed threshold.

[0093] In some embodiments, the controller is further configured to confirm the motor stall condition based on a timer duration that holds a torque-related operating value relative to a stall threshold, and to determine a compensation voltage command based on a modified current command in response to confirming the motor stall condition.

[0094] In some embodiments, confirming a stall condition includes any one of the following: determining that a first stall criterion is continuously met for a first predetermined time period; or determining that a second stall criterion is continuously met for a second predetermined time period, the second predetermined time period being shorter than the first predetermined time period. The first stall criterion may include a torque-related operating value higher than a first torque threshold, and the second stall criterion may include a torque-related operating value higher than a second torque threshold, the second torque threshold being greater than the first torque threshold.

[0095] The foregoing discussion is intended to illustrate the principles and various embodiments of this disclosure. Once the foregoing disclosure is fully understood, many variations and modifications will become apparent to those skilled in the art. The appended claims are intended to be construed as covering all such variations and modifications.

[0096] Ordinal numbers such as “first,” “second,” and “third” can be used to represent different structures, which may be part of the same system or component or different systems or components. Unless the specification clearly describes multiple related structures, such ordinal numbers should not be interpreted as representing any number of related structures in any given system or component.

[0097] The word “example” is used herein to mean something used as an example, illustration, or description. Any aspect or design described herein as an “example” is not necessarily to be construed as being more preferred or advantageous than other aspects or designs. Rather, the use of the word “example” is intended to present a concept in a specific manner. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise stated or clearly apparent from the context, “X comprises A or B” is intended to mean any natural inclusion. That is, if X comprises A; X comprises B; or X comprises both A and B, then “X comprises A or B” is satisfied in any of the foregoing cases. Additionally, the article “a / an” used in this application and the appended claims should generally be interpreted as meaning “one or more” unless otherwise stated or clearly apparent from the context to the singular form. Furthermore, unless so described, the use of the terms “implementation” or “an embodiment” throughout the document is not intended to refer to the same embodiment or implementation.

[0098] The systems, algorithms, methods, and instructions described herein can be implemented in hardware, software, or any combination thereof. Hardware may include, for example, a computer, intellectual property (IP) core, application-specific integrated circuit (ASIC), programmable logic array, optical processor, programmable logic controller, microcode, microcontroller, server, microprocessor, digital signal processor, or any other suitable circuit. In the claims, the term "processor" should be understood to include any of the foregoing hardware, individually or in combination. The terms "signal" and "data" are used interchangeably.

[0099] As used herein, the term "module" can include a packaged functional hardware unit designed for use with other components, a set of instructions executable by a controller (e.g., a processor executing software or firmware), processing circuitry configured to perform a specific function, and self-contained hardware or software components that interface with a larger system. For example, a module can include an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), circuitry, digital logic circuitry, analog circuitry, a combination of discrete circuitry, gate circuits, and other types of hardware, or combinations thereof. In other embodiments, a module can include a memory storing instructions executable by a controller to implement the features of the module.

[0100] Furthermore, in one respect, for example, the system described herein can be implemented using a general-purpose computer or general-purpose processor with a computer program that, when executed, implements any of the corresponding methods, algorithms, and / or instructions described herein. Additionally or alternatively, for example, a special-purpose computer / processor may be utilized, which may contain additional hardware for implementing any of the methods, algorithms, or instructions described herein.

[0101] Furthermore, all or part of the embodiments of this disclosure may take the form of a computer program product accessible from, for example, a computer-usable or computer-readable medium. A computer-usable or computer-readable medium may be, for example, any means capable of tangibly containing, storing, conveying, or transmitting a program for use by or in conjunction with any processor. The medium may be, for example, an electrical, magnetic, optical, electromagnetic, or semiconductor device. Other suitable media may also be used.

[0102] The above embodiments, implementations, and aspects have been described to allow for easy understanding of this disclosure and do not limit it. Rather, this disclosure is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which should be interpreted in the broadest possible sense to cover all such modifications and equivalent structures permitted by law.

Claims

1. A method for controlling an electromechanical braking unit of a vehicle, comprising: Detect the stall status of the motor in the electromechanical braking unit; A modified current command is determined based on the initial current command to generate a balanced sinusoidal phase current during the stall condition. In response to detecting a stall condition in the motor and determining a compensation voltage command based on the modified current command; as well as The inverter is commanded to apply an output voltage to the motor based on the compensation voltage command, thereby generating a balanced sinusoidal phase current in the motor windings during the stall condition, while maintaining the clamping force generated by the electromechanical braking unit.

2. The method according to claim 1, further comprising: Determine the initial voltage command based on the initial current command; as well as The final voltage command is determined to be the sum of the initial voltage command and the compensation voltage command. Specifically, commanding the inverter based on the compensation voltage command includes commanding the inverter to apply the output voltage to the motor based on the final voltage command.

3. The method according to claim 1, wherein, The modified current command includes an adjusted d-axis current command, and Specifically, determining the modified current command includes determining the adjusted d-axis current command based on the q-axis component and adjustment coefficient of the initial current command.

4. The method according to claim 3, wherein, Determining the adjusted d-axis current command includes determining the adjusted d-axis current command according to the following formula: ,in, It is the q-axis component of the initial current command. It is the adjustment coefficient, It is a predetermined reference frequency, and It's time.

5. The method according to claim 1, wherein, The modified current command includes an adjusted q-axis current command, and The command to determine the adjusted q-axis current includes: The q-axis compensation current is determined based on the q-axis component of the initial current command and multiple calibration values; and Combine the q-axis compensation current with the q-axis component of the initial current command.

6. The method according to claim 5, wherein, Determining the adjusted q-axis current command includes: The q-axis compensation current is determined according to the following formula ( ): ,as well as The adjusted q-axis current command is determined according to the following formula ( i q ): , in, It is the q-axis component of the initial current command. and It is a calibration value. It is a predetermined reference frequency, and It's time.

7. The method according to claim 1, wherein, Detecting the stall condition involves comparing the motor's angular velocity with a speed threshold.

8. The method according to claim 1, further comprising: The stall status of the motor is determined based on the duration of a timer that maintains the torque-related operating value relative to the stall threshold. The determination of the compensation voltage command based on the modified current command also responds to confirming the stall status of the motor.

9. The method according to claim 8, wherein, The torque-related operating value is the motor torque command used to determine the initial current command.

10. The method according to claim 8, wherein, The stall condition is confirmed to include any of the following: The first congestion criterion is determined to be continuously met during the first predetermined time period; or The second congestion criterion is determined to be continuously met during a second predetermined time period, which is shorter than the first predetermined time period. The first stall criterion includes the torque-related operating value being higher than a first torque threshold, and The second stall criterion includes the torque-related operating value being higher than the second torque threshold, and the second torque threshold being greater than the first torque threshold.

11. The method according to claim 10, wherein, The first stall criterion also includes the clamping force being higher than a first force threshold, and The second stall criterion further includes the clamping force being higher than a second force threshold, wherein the second force threshold is greater than the first force threshold.

12. A braking system for a vehicle, comprising: An electromechanical braking unit includes an inverter operably coupled to a motor and configured to generate a clamping force; as well as The controller is configured as follows: Detect the stall condition of the motor; A modified current command is determined based on the initial current command to generate a balanced sinusoidal phase current during the stall condition. In response to detecting a stall condition in the motor and determining a compensation voltage command based on the modified current command; as well as The inverter is commanded to apply an output voltage to the motor based on the compensation voltage command, thereby generating a balanced sinusoidal phase current in the motor windings during the stall condition, while maintaining the clamping force generated by the electromechanical braking unit.

13. The braking system according to claim 12, wherein, The controller is also configured to: Determine the initial voltage command based on the initial current command; as well as The final voltage command is determined to be the sum of the initial voltage command and the compensation voltage command. Specifically, commanding the inverter based on the compensation voltage command includes commanding the inverter to apply the output voltage to the motor based on the final voltage command.

14. The braking system according to claim 12, wherein, The modified current command includes an adjusted d-axis current command, and Specifically, determining the modified current command includes determining the adjusted d-axis current command based on the q-axis component and adjustment coefficient of the initial current command.

15. The braking system according to claim 14, wherein, Determining the adjusted d-axis current command includes determining the adjusted d-axis current command according to the following formula: ,in, It is the q-axis component of the initial current command. It is the adjustment coefficient, It is a predetermined reference frequency, and It's time.

16. The braking system according to claim 12, wherein, The modified current command includes an adjusted q-axis current command, and The command to determine the adjusted q-axis current includes: The q-axis compensation current is determined based on the q-axis component of the initial current command and multiple calibration values; and Combine the q-axis compensation current with the q-axis component of the initial current command.

17. The braking system according to claim 16, wherein, Determining the adjusted q-axis current command includes: The q-axis compensation current is determined according to the following formula ( ): ,as well as The adjusted q-axis current command is determined according to the following formula ( i q ): , in, It is the q-axis component of the initial current command. and It is a calibration value. It is a predetermined reference frequency, and It's time.

18. The braking system according to claim 12, wherein, Detecting the stall condition includes determining that the motor speed is less than a speed threshold.

19. The braking system according to claim 12, wherein, The controller is also configured to determine the stall status of the motor based on a timer duration that maintains a torque-related operating value relative to a stall threshold. The determination of the compensation voltage command based on the modified current command also responds to confirming the stall status of the motor.

20. The braking system according to claim 19, wherein, The stall condition is confirmed to include any of the following: The first congestion standard is determined to be continuously met during the first predetermined time period; or The second congestion criterion is determined to be continuously met during a second predetermined time period, which is shorter than the first predetermined time period. The first stall criterion includes the torque-related operating value being higher than a first torque threshold, and The second stall criterion includes the torque-related operating value being higher than the second torque threshold, and the second torque threshold being greater than the first torque threshold.

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