Optimizing motor stop position to reduce loss and vehicle start-up

Abstract

Methods and systems for controlling torque of an electric machine that propels a vehicle while the vehicle is stopped are presented herein. These methods and systems may be applied to configuring synchronization and induction motors for propelling vehicles. When the vehicle speed and the motor speed are zero, the methods and systems may cause the motor to output consistent torque.

Description

Technical Field

[0001] The present disclosure relates to a method and system for positioning a motor that propels a vehicle before the vehicle is started. Background Art

[0002] Electric vehicles may stop from time to time. After the electric vehicle stops, the vehicle may start from zero speed as the vehicle brakes are released and / or the driver requests an increase in torque. The amount of torque required to move the vehicle in the intended forward or reverse direction may be a function of the mass of the vehicle and the grade of the road or road surface on which the vehicle is parked. If the torque output by the propulsion source (e.g., an electric machine) of the electric vehicle is less than the torque required to overcome the mass of the vehicle and the grade of the road surface on which the vehicle is located, then when the brakes of the vehicle are released, the vehicle may not move or move in an unintended direction. To ensure that the electric vehicle has a startable output torque to enable it to move in the intended direction, one method is to set the inverter of the electric vehicle that supplies power to the vehicle propulsion source to be oversized so as to provide more current to the vehicle propulsion source. Another potential solution to the above problem is to increase the size of the vehicle propulsion motor so that the electric vehicle propulsion can produce more torque. However, oversizing the inverter and motor may increase the financial cost of the system and increase system losses. Therefore, it is best to provide a method to increase the starting torque without oversizing the inverter or motor of the vehicle. Summary of the invention

[0003] The inventors of the present invention recognized the above problems and developed a method of operating a vehicle, which includes rotating a motor to a predetermined position when the vehicle is parked on a first surface having a first slope greater than a threshold slope.

[0004] By rotating the motor according to the slope of the vehicle's parking surface, a technical achievement of generating uniform torque capacity for a motor configured to propel a vehicle can be achieved. In particular, the angular position of the motor rotor can be adjusted from a position where the motor can generate a smaller torque at zero speed to a position where a larger torque can be generated at zero speed. For example, if the rotor of the electric machine is in a first angular position, the torque output capacity of the electric machine (e.g., the ability to generate a certain amount of torque) can generate 52,000 Newtons of traction at zero speed of the vehicle. However, if the rotor angular position is adjusted by 30 (or 15 or 7.5) degrees, the torque output capacity of the motor at zero vehicle speed can reach 60,000 Newtons. Therefore, when the output torque capacity of the motor is less than the maximum output torque capacity of the motor at zero vehicle speed, the rotation angle of the motor rotor can be adjusted.

[0005] The present invention has several advantages. In particular, the method can produce high torque output at zero motor speed. In addition, the method can also provide a more stable motor torque output at zero motor speed. In addition, the method can be applied to synchronous and induction motors of different configurations (such as 3-phase and 6-phase).

[0006] It should be understood that the above summary is intended to introduce some concepts further described in the detailed description in a simplified form. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is solely determined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic diagram of an example vehicle including an electric machine configured to propel the vehicle.

[0008] Figure 2 A graph of the hypothetical traction forces that can be produced by the motor is shown.

[0009] Figure 3-8 An example of the operating characteristics of a three-phase motor is shown.

[0010] Fig. 9 An example of a method of operating a vehicle motor is shown.

[0011] Fig.10 and Fig.11 An example of a driveline clutch is shown. DETAILED DESCRIPTION

[0012] A method and system for operating a vehicle electric propulsion source is described herein. The method and system are applicable to electric vehicles and hybrid vehicles. In one example, the method and system rotates a rotor of an electric machine under selected vehicle operating conditions to provide consistent tractive effort and consistent electric machine output torque. Figure 1 A schematic diagram of an example vehicle is shown. Figure 2 Shows the relationship between vehicle traction and vehicle speed. Figure 3-8 The operating characteristics of a synchronous motor are shown. Fig. 9 A flow chart of an example method of operating a vehicle and an electric machine is shown. Fig.10 and Fig.11 An example of a driveline clutch is shown.

[0013] Figure 1An example of a vehicle propulsion system 199 for a vehicle 10 is shown. A front end 110 of the vehicle 10 is labeled, and a rear end 111 of the vehicle 10 is also labeled. When the front of the vehicle moves the vehicle 10, the vehicle 10 moves in a forward direction. When the rear of the vehicle moves the vehicle 10, the vehicle 10 moves in a reverse direction. The vehicle propulsion system 199 includes a propulsion source 105 (e.g., a motor), but two or more propulsion sources may be provided in other examples. In one example, the propulsion source 105 may be a synchronous or induction motor that may operate as a motor or a generator. The propulsion source 105 is fixed to the electrified axle 190 and transmits power from the rotor 105a to the gear set 107. Figure 1 In the figure, the mechanical connections between the components are represented by solid lines, while the electrical connections between the components are represented by dotted lines.

[0014] The vehicle propulsion system 199 includes an electrified axle 190 (e.g., an axle including an integrated electric machine that provides propulsion for the vehicle). The electrified axle 190 may include two axles, including a first or right axle 190a and a second or left axle 190b. The vehicle 10 also includes front wheels 102 and rear wheels 103.

[0015] The electrified axle 190 may be an integrated axle including a differential gear 106, a gear set 107, and a propulsion source 105. The gear set 107 may be referred to as a step ratio transmission and may include a plurality of gears and one or more clutches for shifting between gears. In one example, the gear set may include a first gear 108, a second gear 109, and a third gear 131. In addition, the electrified axle 190 may also include one or more clutch actuators 112 for shifting one or more clutches 145. The clutch 145 may be configured as a dog clutch, a wet clutch, a friction clutch, a curved clutch, or other known configurations. The encoder 168 provides an indication of the position of the motor and one half of the clutch 145 (e.g., the upstream power path side of the clutch 145), and the encoder 169 provides an indication of the clutch position of the downstream clutch power path side of the clutch 145. Fig.10 and Fig.11 Two clutch configuration examples are shown. The electric axle 190 may include a first speed sensor 119 for sensing the speed of the propulsion source 105 on the input side of the clutch 145 and a second speed sensor 122 for sensing the speed on the output side of the clutch 145. The power inverter 115 is electrically coupled to the propulsion source 105. The axle control unit 116 is electrically connected to the sensors and actuators of the electrified axle 190.

[0016] The propulsion source 105 may transmit mechanical power to or receive mechanical power from the gear set 107. Therefore, the gear set 107 may be a multi-speed gear set that can shift between gears (e.g., the first gear 108 and the second gear 109) when a command is issued through the axle control unit 116. The axle control unit 116 includes a processor 116a and a memory 116b. The memory 116b may include a read-only memory, a random access memory, and a keep-alive memory. The axle control unit 116 may receive a transmission temperature through a sensor 133. The gear set 107 may transmit mechanical power to or receive mechanical power from the differential gear 106. The differential gear 106 may transmit mechanical power to or receive mechanical power from the rear wheels 103 through the right axle 190a and the left axle 190b. The propulsion source 105 may consume alternating current (AC) power provided by the power inverter 115. Alternatively, the propulsion source 105 may provide AC power to the power inverter 115. The power inverter 115 may receive high voltage direct current (DC) from a battery 160 (e.g., a traction battery, which may also be referred to as an energy storage device or battery pack). The power inverter 115 may convert the DC power from the battery 160 into AC power for use by the propulsion source 105. In addition, the power inverter 115 may also provide AC power from the propulsion source 105. The power inverter 115 may convert the AC power from the propulsion source 105 into DC power for storage in the battery 160.

[0017] The battery 160 may periodically receive electrical energy from a power source, such as a fixed power grid 5 located outside the vehicle (e.g., not part of the vehicle). As a non-limiting example, the vehicle propulsion system 199 may be configured as a plug-in electric vehicle (EV), whereby the battery 160 may be provided with electrical energy via the power grid 5 and the charging station 12. The charge may be delivered to the battery 160 via the plug socket 100.

[0018] The battery 160 may include a BMS controller 139 (e.g., a battery management system controller) and a distribution box 162. The BMS controller 139 may provide charge balancing between energy storage elements (e.g., battery cells) and communication with other vehicle controllers (e.g., the vehicle control unit 152). The BMS controller 139 includes a core processor 139a and memory 139b (e.g., random access memory, read-only memory, and update retention memory).

[0019] The vehicle 10 may include a vehicle control unit (VCU) 152 that can communicate with a power inverter 115, an axle control unit 116, a friction or foundation brake controller 170, a global positioning system (GPS) 188, a BMS controller 139, a dashboard 130, and components therein via a controller area network (CAN) 120. The VCU 152 includes a memory 114, which may include a read-only memory (ROM or non-transitory memory) and a random access memory (RAM). The VCU also includes a digital processor or central processing unit (CPU) 153 and inputs and outputs (I / O) 118 (e.g., digital inputs, digital outputs, analog inputs, and analog outputs including counters, timers, and discrete inputs). The VCU may receive signals from sensors 154 and provide control signal outputs to actuators 156. The sensors 154 may include, but are not limited to, lateral acceleration sensors, longitudinal acceleration sensors, yaw rate sensors, tilt sensors, temperature sensors, battery voltage and current sensors, and other sensors described herein. In addition, the sensors 154 may also include a steering angle sensor 197, a driver demand pedal position sensor 141, a vehicle ranging sensor (including radio detection and ranging (RADAR), light detection and ranging (LIDAR), sound navigation and ranging (SONAR), and a brake pedal position sensor 151). The actuators may include, but are not limited to, the inverter, transmission controller, display device, human-machine interface, friction brake system, and battery controller described herein.

[0020] The driver demand pedal position sensor 141 is connected to the driver demand pedal 140 for determining the degree of depression of the driver demand pedal 140 by a human 142. The brake pedal position sensor 151 is connected to the brake pedal 150 for determining the degree of depression of the brake pedal 150 by a human 142. The steering angle sensor 197 is configured to determine the steering angle according to the position of the steering wheel 198.

[0021] The vehicle propulsion system 199 is provided with a global positioning system 188 which receives timing and position data from one or more GPS satellites 189. The global positioning system may also include a geographic map in ROM for determining the location of the vehicle 10 and the characteristics of the roads on which the vehicle 10 may be traveling.

[0022] The vehicle propulsion system 199 may also include a dashboard 130 with which the vehicle operator can interact. The dashboard 130 may include a display system 132 configured to display information to the vehicle operator. As a non-limiting example, the display system 132 may include a touch screen or a human-machine interface (HMI) display that enables the vehicle operator to view graphical information and enter commands. In some examples, the display system 132 may be wirelessly connected to the Internet (not shown) via the VCU 152. Thus, in some examples, the vehicle operator may communicate with an Internet website or software application (App) and the VCU 152 via the display system 132.

[0023] The instrument panel 130 may further include an operator interface 136 through which the vehicle operator can adjust the operating state of the vehicle. Specifically, the operator interface 136 can be configured to activate and / or deactivate the operation of the vehicle drive system (e.g., the propulsion source 105) based on the operator input. In addition, the operator can request the axle mode (e.g., parking, reverse, neutral, drive) through the operator interface. Various examples of the operator interface 136 may include an interface using a physical device (e.g., a key) that can be inserted into the operator interface 136 to activate the electric axle 190 and the propulsion source 105 and turn on the vehicle 10, and can also be removed to turn off the electric axle and the propulsion source 105 to turn off the vehicle 10. The electric axle 190 and the propulsion source 105 can be started by supplying power to the propulsion source 105 and / or the power inverter 115. The electric axle 190 and the motor can be deactivated by stopping the supply of power to the electric axle 190 and the propulsion source 105 and / or the power inverter 115. Still other examples may additionally or alternatively use a start / stop button that is manually pressed by an operator to start or stop the electric axle 190 and the propulsion source 105 to start or shut down the vehicle. In other examples, remote electric axle or electric machine activation may be initiated by a remote computing device (not shown), such as a cell phone or smartphone-based system, where the user's cell phone sends data to a server that communicates with the vehicle control unit 152 to activate the electric axle 190 including the inverter and electric machine. The spatial orientation of the vehicle 10 is indicated by the axis 175.

[0024] Also shown is a base or friction brake controller 170 of the vehicle 10. The friction brake controller 170 can selectively apply and release the friction brakes (e.g., 172a and 172b) by allowing hydraulic fluid to flow to the friction brakes. The application and release of the friction brakes can prevent the friction brakes from locking the front wheels 102 and the rear wheels 103. The wheel position or vehicle speed sensor 161 can provide wheel speed data to the friction brake controller 170. The vehicle propulsion system 199 can provide torque to the rear wheels 103 to propel the vehicle 10.

[0025] A human or autonomous driver may request a driver requested wheel torque, or a driver requested wheel power, by depressing a driver requested pedal 140 or issuing a driver requested wheel torque / power request to the vehicle control unit 152. The vehicle control unit 152 may then request the propulsion source 105 to provide torque or power by instructing the axle control unit 116. The axle control unit 116 may command the power inverter 115 to provide the driver requested wheel torque / power through the electrified axle 190 and the propulsion source 105. The power inverter 115 may convert the direct current of the battery 160 into alternating current and supply the alternating current to the propulsion source 105. The propulsion source 105 rotates and transmits torque / power to the gear set 107. The gear set 107 may transmit the torque of the propulsion source 105 to the differential gear 106, and the differential gear 106 transmits the torque of the propulsion source 105 to the rear wheels 103 through the axles 190a and 190b.

[0026] In the event that the driver requests a full release of the pedal, when the speed of the vehicle 10 is greater than a threshold speed, the vehicle control unit 152 may request a small amount of negative braking power or regenerative braking power to gradually slow the speed of the vehicle 10. The amount of regenerative braking force requested may be a function of the driver's requested pedal position, the battery state of charge (SOC), the vehicle speed, and other conditions. If the driver requests a full release of the pedal 140, and the vehicle speed is less than a threshold speed, the vehicle control unit 152 may request a small amount of positive torque / positive power (e.g., propulsion torque) from the propulsion source 105, which may be referred to as a climbing torque or climbing power. The creeping torque or power may keep the vehicle 10 stationary when traveling on a slight slope.

[0027] The human or autonomous driver may also request a negative or regenerative driver requested braking torque, or a driver requested braking force, by depressing the brake pedal 150 or issuing a driver requested braking force request to the vehicle control unit 152. The vehicle control unit 152 may request that a first portion of the driver requested braking force be generated by the electric axle 190 and the propulsion source 105 by instructing the axle control unit 116. In addition, the vehicle control unit 152 may also request that a portion of the driver requested braking force be provided by the friction brake 172 through the friction brake controller 170 to provide a second portion of the driver requested braking force.

[0028] After the vehicle control unit 152 determines the braking power request, the vehicle control unit 152 may instruct the axle control unit 116 to distribute the portion of the braking power requested by the driver to the electrified axle 190. The power inverter 115 may convert the AC power generated by the propulsion source 105 into DC power for storage in the battery 160. The propulsion source 105 may convert the vehicle kinetic energy into AC power.

[0029] The axle control unit 116 includes a predetermined transmission shift schedule according to which the fixed ratio gears of the gear set 107 are selectively engaged and disengaged. The shift schedule stored in the axle control unit 116 selects shift points or shift conditions based on the wheel torque requested by the driver and the vehicle speed.

[0030] therefore, Figure 1 A system provides a vehicle system, the system comprising: an electric machine configured to propel the vehicle; a transmission system clutch; an inverter electrically coupled to the electric machine; and a controller, the controller comprising executable instructions stored in a non-transitory memory, the instructions causing the controller to adjust the rotational position of the rotor of the electric machine in response to the ground slope when the vehicle is stopped or the amount of starting when the vehicle is stopped. In a first example, the vehicle system further comprises additional executable instructions, the instructions causing the controller to further adjust the rotational position of the rotor in response to the rotational position of the electric machine, at which position the power loss of the electric machine is minimized at zero speed of the electric machine. In a second example, which may include the first example, the vehicle system further comprises additional executable instructions, the additional executable instructions causing the controller to further adjust the rotational position of the rotor in response to the rotational position of the electric machine, wherein the torque output of the electric machine is maximized at zero speed of the electric machine. In a third example, which may include one or both of the first and second examples, the vehicle system further comprises additional executable instructions causing the controller to apply vehicle brakes in response to the vehicle stopping. In a fourth example, which may include one or more of the first to third examples, the vehicle system further includes additional executable instructions that cause the controller to open the clutch when the vehicle is stopped and the surface level is greater than a threshold amount or the amount of launch is greater than a threshold amount, and then adjust the rotational position of the rotor when the vehicle is stopped. In a fifth embodiment, which may include one or more of the first to fourth embodiments, the vehicle system includes a clutch wherein the clutch is a dog clutch. In a sixth example, which may include one or more of the first to fourth examples, the vehicle system includes a clutch wherein the clutch is a friction clutch.

[0031] Now watch Figure 2 , a hypothetical motor diagram is shown illustrating the performance of a vehicle with a two speed gear set. The graph 200 includes a vertical axis 201 representing the tractive effort generated by the vehicle. In the graph, the tractive effort generated by the vehicle and the motor when the vehicle speed is zero represents the non-optimal tractive effort of the vehicle at zero vehicle speed. The tractive effort of the vehicle increases in the direction of the vertical axis arrow. The graph 200 also includes a horizontal axis 203 representing the vehicle speed. The vehicle speed increases from Figure 2 increases from the left to the right. Figure 2Also shown are lines 250-260 representing traction required to meet the vehicle performance criteria when the vehicle is traveling on a road surface with a constant grade, as a function of vehicle speed. Line 250 represents the traction required to meet the vehicle performance criteria when the vehicle is traveling on a road surface with a grade of 35%. Line 252 represents the traction required to meet the vehicle performance criteria when the vehicle is traveling on a road surface with a grade of 30%. Line 254 represents the traction required to meet the vehicle performance criteria when the vehicle is traveling on a road surface with a grade of 15%. Line 256 represents the traction required to meet the vehicle performance criteria when the vehicle is traveling on a road surface with a grade of 5%. Line 260 represents the traction required to meet the vehicle performance criteria when the vehicle is traveling on a road surface with a grade of 0%.

[0032] Line 202 represents the maximum first gear peak power tractive effort of the vehicle (e.g., the maximum tractive effort that the vehicle can generate) that can be generated within a predetermined time (e.g., 10 seconds) when the vehicle transmission is engaged in first gear. Line 204 represents the maximum second gear peak power tractive effort of the vehicle that can be generated within a predetermined time when the vehicle transmission is engaged in second gear. Line 206 represents the maximum first gear continuous power tractive effort capacity of the vehicle (e.g., the maximum tractive effort that the vehicle can generate continuously) that can be generated continuously when the vehicle transmission is engaged in first gear. Line 208 represents the maximum second gear continuous power tractive effort that can be generated continuously when the vehicle transmission is engaged in second gear.

[0033] It can be observed that when the vehicle speed is zero, the vehicle's maximum first gear peak power tractive force is 15% lower than when the vehicle speed is between 2 and 20 km / h (e.g., the force shown by triangle 213). Similarly, when the vehicle speed is zero, the vehicle's maximum second gear peak power tractive force is 15% lower than when the vehicle speed is between 2 and 20 km / h. At a vehicle speed of approximately 2 km / h, based on the vehicle's performance indicators, the vehicle may have sufficient tractive force to negotiate a 35% grade when the vehicle is in first gear. However, at zero vehicle speed, based on the vehicle's performance indicators, the vehicle's tractive force is insufficient to negotiate a 35% grade when the vehicle is in first gear. However, when the vehicle is in first gear, based on the vehicle's performance indicators, the vehicle's tractive force 213 is sufficient to negotiate a 30% grade 252. The systems and methods described herein are intended to eliminate the problem of insufficient motor torque so that the vehicle can obtain motor torque even at zero speed. Highlighted area 215 represents traction, which in a system not including the traction optimization method described herein would enable the vehicle to negotiate a 30% grade by increasing the output of the motor and its associated inverter to meet the vehicle performance target. In contrast, the system and method described herein enables the motor and vehicle to provide traction to negotiate a 35% grade at zero vehicle speed and higher.

[0034] Now please see Figure 3-8 , the figure shows the operating characteristics of a three-phase synchronous motor. Figure 3301 represents the unit current or normalized current of the motor. The horizontal axis 303 represents the current angle, which is marked below the horizontal axis.

[0035] Trace 302 shows the current of the first phase of the motor. Trace 304 shows the current of the second phase of the motor. Trace 306 shows the current of the third phase of the motor. The phase currents are 120 degrees apart.

[0036] Now please see Figure 4 , the figure shows the absolute value of each phase current in the three-phase current of the motor. The vertical axis 401 represents the unit current or normalized current of the motor. The horizontal axis 403 represents the current angle, which is displayed below the horizontal axis.

[0037] Trace 402 represents the absolute value of the first phase current of the motor. Trace 404 represents the absolute value of the second phase current of the motor. Trace 406 represents the absolute value of the third phase current of the motor.

[0038] Now please see Figure 5 , the graph shows the conduction power loss of all phases of a three-phase motor operating at a constant torque output as a function of the current angle. The vertical axis 501 represents the unit or normalized power loss, and the power loss increases in the direction of the vertical axis arrow. The horizontal axis 503 represents the current angle, and the motor current angle is represented below the horizontal axis.

[0039] Trace 502 represents the conduction power loss of the motor under a-phase current (e.g., first phase current). Trace 504 represents the conduction power loss of the motor under b-phase current (e.g., second phase current). Trace 506 represents the conduction power loss of the motor under c-phase current (e.g., third phase current). Trace 508 represents the average power loss.

[0040] Now please see Figure 6 , the maximum conduction power loss of all current phases of a three-phase motor operating at a constant torque output is shown as a function of the current angle. The vertical axis 601 represents the unit or normalized power loss, and the power loss increases in the direction of the vertical axis arrow. The horizontal axis 603 represents the current angle, and the current angle is marked below the horizontal axis.

[0041] Trace 602 represents the maximum conduction power loss of all current phases of the motor. It can be seen that the maximum conduction power loss can be minimized when the motor electrical angle is 0 degrees, 60 degrees, 120 degrees, 180 degrees, 240 degrees, 300 degrees and 360 degrees. By positioning the rotor at 0 degrees, 60 degrees, 120 degrees, 180 degrees, 240 degrees or 300 degrees, the motor losses can be minimized, thereby maximizing the motor torque output. Therefore, if the motor rotor stops at 140 degrees, the motor rotor can be rotated backward by 20 degrees to optimize the motor output torque. On the other hand, if the motor rotor stops at 170 degrees, the rotor can be rotated forward by 10 degrees to maximize the motor torque and power output, so that the rotor stops at 180 degrees to maximize the motor power output.

[0042] See also Figure 7 , the figure shows the maximum current value among all phase currents of a three-phase motor running at a constant torque output. The vertical axis 701 represents the unit or normalized current value of all phase currents of the three-phase motor, and the current value increases in the direction of the vertical axis arrow. The horizontal axis 703 represents the current angle, and the current angle is displayed below the horizontal axis.

[0043] Trace 702 represents the maximum current value among all phase currents of a three-phase motor operating at constant torque. It can be seen that the maximum current occurs at 30 degrees, 90 degrees, 150 degrees, 210 degrees, 270 degrees, and 330 degrees. The minimum current level for operating the motor at a constant torque output occurs at 0 degrees, 60 degrees, 120 degrees, 180 degrees, 240 degrees, 300 degrees, and 360 degrees. Therefore, when the motor speed is zero, the current can be minimized by positioning the rotor at 0, 60, 120, 180, 240, or 300 electrical degrees.

[0044] See also Figure 8 , the figure shows the peak or maximum torque output of a three-phase motor running at a constant peak current as a function of the current angle. The vertical axis 801 represents the peak torque output of the motor when running at a constant peak current. The horizontal axis 803 represents the current angle, which is indicated below the horizontal axis.

[0045] Trace 802 represents the maximum or peak torque at a constant peak current. It can be seen that the maximum or peak torque output of the motor occurs at electrical angles of 0, 60, 120, 180, 240, 300 and 360 degrees. By positioning the rotor at 0, 60, 120, 180, 240 or 300 electrical degrees, the motor torque output can be maximized when the motor speed is zero. Therefore, if the motor rotor stops at 140 degrees, the motor rotor can be rotated backward 20 degrees to optimize the motor output torque. On the other hand, if the motor rotor stops at 170 degrees, the rotor can be rotated forward 10 degrees to maximize the motor torque and power output, so that the rotor stops at 180 degrees, at which time the motor power output can be maximized.

[0046] Understandably, Figure 3-8 The operating conditions shown can be used as a basis for adjusting the position of the rotor of the three-phase motor of the propulsion source to stop (e.g., not rotate). The operating conditions for adjusting the rotor position of the six-phase motor can also be used as a basis for adjusting the rotor position of the motor. The diagram and data of the six-phase motor can be generated similarly. Figure 3-8 This is determined by the method of graphs and data.

[0047] Now please see Fig. 9 , a flow chart of a method for operating a vehicle including an electric motor is shown. Fig. 9 The method can be used with Figure 1 The one or more controllers may execute at least a portion of method 900 by changing the working state of one or more actuators in the real world. Method 900 may be implemented at least in part as executable instructions stored in a computer such as Figure 1 In the non-scratch register of the controller in the system shown.

[0048] At 902, method 900 determines whether the vehicle speed (VS) is within a zero threshold speed range. In one example, the threshold speed may be 3 km / h. If method 900 determines that the vehicle speed is within a zero threshold speed range, the answer is "yes", and method 900 proceeds to 904. Otherwise, the answer is no, and method 900 proceeds to 950.

[0049] At 950, method 900 adjusts the motor torque output based on a function of the requested driver demand torque and the requested brake torque. The requested driver demand torque may be based on the position of the driver demand pedal, and the requested brake torque may be based on the position of the brake pedal. Thus, if the position of the driver demand pedal indicates that the motor 105 is required to output 100 Newton-meters of torque, the motor 105 will be commanded to output 100 Newton-meters of torque. Method 900 exits.

[0050] At 904, method 900 estimates the grade of the road or road surface on which the vehicle is traveling. In one example, the grade of the road or road surface can be estimated by an inclinometer. In other examples, method 900 can determine a vehicle performance indicator based on the mass of the vehicle (including the mass of the load applied to the vehicle) and the grade of the road or road surface. In one example, the performance indicator can be the rate of change of vehicle speed for a given driver demand torque or power. After determining the grade of the road or road surface and / or the vehicle performance indicator, method 900 proceeds to 906.

[0051] At 906, method 900 determines whether the road or road slope can be overcome when the vehicle speed is zero and the motor rotor is not positioned so that the motor produces maximum torque when the motor speed is zero. In other words, method 900 determines whether the vehicle and its total mass (e.g., the mass of the vehicle plus the mass of the load loaded on the vehicle) can be advanced from zero speed to a predetermined speed (e.g., 3 km / h) under the power of the motor without engaging the first gear when driving on a road or road with a determined slope when the motor rotor is not positioned so that the motor produces maximum torque at zero speed. If so, the answer is "yes" and method 900 enters 952. Otherwise, the answer is no and method 900 enters 908. When the performance of the vehicle on the slope can meet the requirements, step 906 allows avoiding adjusting the motor rotor. In addition, when the speed of the motor rotor is zero, the position of the motor rotor does not reach the maximum torque output, step 906 can prevent adjusting the position of the motor rotor when the vehicle launch index is met.

[0052] In some embodiments, method 900 may adjust the angular position of the motor rotor based on the rotor not rotating and the expected rate of change of vehicle speed from zero speed to a predetermined speed during vehicle launch is less than a vehicle launch index. The launch index may be the rate of change of vehicle speed from zero vehicle speed to a predetermined vehicle speed. A simplified expected rate of change of vehicle speed may be based on the stopped position of the rotor (to estimate the motor torque at zero vehicle speed, which is determined by a lookup table containing predetermined torque values), the vehicle mass, and the gear ratio between the motor and the wheel (vehicle speed change = force applied to the wheel / vehicle mass, where the force applied to the wheel is the motor torque at zero vehicle speed multiplied by the gear ratio between the motor and the wheel divided by the wheel radius).

[0053] At 952, method 900 adjusts the motor torque based on the creep torque demand and the driver demand torque. The creep torque demand can be a constant torque that allows the vehicle to travel at a low speed (e.g., less than 5 km / h) without providing the driver demand torque shortly after the vehicle stops on a flat road and the brake pedal is released. For roads with lower slopes, the creep torque is sufficient to keep the vehicle speed at or above zero. Method 900 can also adjust the motor torque based on the torque required by the driver. For example, if the driver demand torque is adjusted to 0 to 40 Newton-meters, the motor output torque can be adjusted to 0 to 40 Newton-meters. In other examples, the driver's demand can be a required wheel torque, and the electric machine torque can be adjusted to a torque that produces the required wheel torque. Method 900 returns to 902.

[0054] At 908, method 900 determines whether the vehicle speed is zero. If so, the answer is "yes" and method 900 proceeds to 910. Otherwise, the answer is no and method 900 proceeds to 952. The tires, drivetrain, and gear clearance of the vehicle may affect the resting position of the motor rotor. When the motor speed is zero, the position of the motor rotor may affect the amount of torque generated by the motor at zero speed.

[0055] At 910 , method 900 applies the vehicle brakes to maintain the vehicle at zero speed. Method 900 proceeds to 912 .

[0056] At 912, method 900 retrieves one or more target motor rotor positions from a memory (e.g., a read-only memory). The one or more target motor rotor positions may be determined by modeling or commanding a maximum motor torque, each increment of one rotor degree, while monitoring the motor torque while the motor speed is held at zero. Figure 6 and Figure 8 As shown in , the rotor position can be the rotor position where the motor produces the maximum output torque, or the rotor position where the motor loss is the minimum. Figure 6 and Figure 8 As shown, for a three-phase motor, the rotor positions may be 0 degrees, 60 degrees, 120 degrees, 180 degrees, 240 degrees, and 300 degrees. Other rotor positions for a six-phase motor may also be generated in a similar manner. Method 900 proceeds to 914.

[0057] At 914, method 900 opens a clutch in the vehicle driveline to decouple the motor from the wheels. By decoupling the motor from the vehicle wheels, the motor rotor can be rotated to a position where the motor can produce maximum torque output at zero motor speed without moving the vehicle. In some examples, the clutch can be a toothed dog clutch, while in other examples, the clutch can be a wet friction clutch or other known clutch type. The clutch type may affect the position of the rotor to increase the torque output at zero motor speed. For example, for a toothed dog clutch, the number of dog teeth and their angular orientation become part of the equation when considering which rotor positions 912 can be used to increase the motor torque output at zero motor speed. In one case, the rotor position 912 is calculated using the motor orientation and the last angular orientation of the dog teeth with the brake locked 910, the power path fixed, and the vehicle speed at zero. In another example, the motor will have an encoder (e.g., Figure 1 168), so the motor angular position is known, the angular position of the first clutch tooth 1002 (e.g. Fig.10 ) can be oriented and calibrated according to the motor encoder, and the encoder calibrated according to the angular orientation of the second clutch tooth 1004 (for example Figure 1 169) can be added to the second clutch power path side to understand the mating tooth orientation. When one or two encoders are used, brake lock 910 can be used or not to calculate rotor positions 912, which can be used to increase the motor torque output when the motor speed is zero, such as in the event of a vehicle rollover. In cases where the clutch design may limit the motor rotor position due to tooth interference, the rotor can be rotated to a position closest to one of the rotor positions retrieved from memory. The motor may need to rotate more and skip some clutch teeth to achieve the optimal clutch tooth motor angle, thereby increasing the motor torque output when the motor speed is zero. When the clutch type does not interfere with the rotor position adjustment, the method 900 can rotate the rotor to one of the exact rotor positions retrieved from memory.

[0058] The method 900 rotates the motor rotor to a position closest to one of the positions retrieved from the controller memory at step 912, which position is dependent on the teeth of the dog clutch (if present). When the vehicle includes a dog clutch, the clutch teeth on the motor side of the dog clutch are aligned so as to immediately engage the teeth on the clutch side opposite the motor side without tooth butting, rotation, or jumping, so that the motor is not moved from a position closest to its optimal position due to tooth engagement. For example, if the motor rotor stops at 100 degrees, and the closest position (e.g., 300 degrees) where the motor rotor can stop positioning to output maximum torque when engaged with the dog clutch teeth is 298 degrees, the motor rotor is rotated to 298 degrees. For a friction clutch, the motor rotor can be adjusted to a position retrieved from the controller memory (e.g., 180 degrees, 240 degrees, 300 degrees, etc.). The motor rotor can be rotated clockwise or counterclockwise to adjust the rotor position to the closest rotor position retrieved from the memory. After adjusting the position of the motor rotor, the method 900 enters 918.

[0059] At 918 , method 900 closes the driveline clutch to re-couple the electric machine to the wheels of the vehicle after adjusting the position of the electric machine rotor to maximize the torque output of the electric machine at zero speed. Method 900 proceeds to 920 .

[0060] At 920, method 900 adjusts the motor torque and brake torque based on the creep torque demand, the requested driver demand torque, and the requested brake torque. The creep torque demand can be a constant torque that allows the vehicle to travel at a low speed (e.g., less than 5 km / h) without providing the driver demand torque shortly after the vehicle stops on a flat road and the brake pedal is released. For roads with lower slopes, the creep torque is sufficient to keep the vehicle speed at or above zero. Method 900 also adjusts the motor torque based on the driver's requested torque and adjusts the friction brake torque based on the requested brake torque. For example, if the required brake torque is 50 Newton-meters and the required driver demand torque is 40 Newton-meters, the vehicle friction brakes can be adjusted to provide the required brake torque, and the motor output torque can be adjusted to equal the required driver demand torque. In other examples, the requested driver demand can be a requested wheel torque, and the electric machine torque can be adjusted to a torque that produces the requested wheel torque. Method 900 continues to exit.

[0061] Thus, as the torque output of the motor varies with the angular position of the motor rotor, the position of the motor rotor can be rotated to optimize the torque output of the motor. When the motor speed is zero, the position of the motor rotor can be adjusted to a position where the motor output torque is the maximum available torque of the motor.

[0062] therefore, Fig. 9A method of operating a vehicle is provided, the method comprising: when The method further includes: when the vehicle is parked on a first surface, rotating the electric machine to a predetermined position, and the first level of the first surface is greater than the threshold level. In a first example, the method further includes: when the vehicle is parked on a second surface, not rotating the electric machine to a predetermined position, and the second level of the second surface is less than the threshold level. In a second example, which may include the first example, the method includes wherein the predetermined position is a position within a predetermined range of the electric machine angular rotor position, and wherein the torque output of the electric machine is the maximum torque output of the electric machine at zero speed. In a third example, which may include one or both of the first and second examples, the method includes wherein the electric machine is a synchronous motor or an induction motor. In a fourth example, which may include one or more of the first to third examples, the method includes wherein the predetermined position is stored in a memory of the controller, and the first encoder and the second encoder provide data to rotate the electric machine to the predetermined position. In a fifth example, which may include one or more of the first to fourth examples, the method includes wherein the predetermined position is a function of the current angle provided to the motor. In a sixth example, which may include one or more of the first to fifth examples, the method includes wherein the first level is estimated by an inclinometer. In a seventh example, which may include one or more of the first to sixth examples, the method further includes adjusting a torque output of the electric machine in response to a creep torque request, a driver demand torque request, and a brake torque request after rotating the electric machine to a predetermined position.

[0063] also, Fig. 9 The method may also provide a method for operating a vehicle, comprising: Applying a vehicle brake, opening a transmission clutch, and rotating the electric machine to a predetermined position in response to the vehicle stopping. In a first example, the method includes: wherein the predetermined position is the closest angular position of the electric machine rotor relative to the electric machine position when the vehicle initially stops, at which position the power loss of the electric machine is minimized. In a second example, which may include the first example, the method includes wherein the predetermined position is the closest angular position of the electric machine rotor relative to the electric machine position when the vehicle initially stops, at which position the torque output of the electric machine is maximum. In a fourth embodiment, which may include one or more of the first to third embodiments, the method includes wherein the clutch is a dog clutch including teeth, and wherein the predetermined position is within a predetermined angular tooth position range of the dog clutch, wherein the torque output of the electric machine is equal to the maximum output torque of the electric machine at zero speed of the electric machine. In a fifth embodiment, which may include one or more of the first to fourth embodiments, the method includes the clutch being a friction clutch.

[0064] In another way of expressing it, Fig. 9A method for operating a vehicle may be provided, comprising: in response to a rotor not rotating and an expected rate of change of vehicle speed from zero vehicle speed to a predetermined vehicle speed being less than a launch metric for the vehicle, adjusting an angular position of a rotor of an electric motor. In a first example, the launch metric may be a rate of change of vehicle speed from zero vehicle speed to a predetermined vehicle speed (e.g., five kilometers per hour).

[0065] Reference now Fig.10 , a perspective view of the two halves of clutch 145 is shown. In this example, clutch 145 is a dog clutch including teeth 1002 on a first side of clutch 145 that engage teeth 1004 on a second side of clutch 145.

[0066] Now please see Fig.11 , which is a perspective view of the clutch 145. In this example, the clutch 145 is a wet friction clutch. The clutch 145 includes a friction plate 1102 for transmitting torque on the clutch 145.

[0067] Please note that the control and estimation routine examples included herein can be used in various powertrain and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-volatile memory and can be executed by a control system including a controller in combination with various sensors, actuators and other transmission and / or vehicle hardware. In addition, some methods may be physical operations taken in the real world to change the state of the device. Therefore, the actions, operations and / or functions described can graphically represent the code that will be programmed into the non-volatile memory of a computer-readable storage medium in the vehicle and / or transmission control system. The specific routines described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. Therefore, the various operations, operations and / or functions illustrated can be performed in the illustrated order, in parallel, or omitted in some cases. Similarly, the processing order is not necessarily required to achieve the features and advantages of the examples described herein, but is only for ease of illustration and description. Depending on the specific strategy used, one or more of the actions, operations and / or functions illustrated can be repeatedly performed. If necessary, one or more method steps described herein can be omitted.

[0068] Although various embodiments are described above, it should be understood that these embodiments are examples only and not limitations. It is obvious to those familiar with the relevant technology that the disclosed subject matter can be embodied in other specific forms without departing from the spirit of the subject matter. Therefore, the embodiments described above should be regarded as illustrative and not restrictive in all respects. Therefore, the configurations and routines disclosed herein are exemplary in nature, and these specific examples should not be regarded as restrictive because there can be many variations. For example, the above-mentioned technology can be applied to electric vehicles and hybrid vehicles, including induction and synchronous motors. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of various systems and configurations, as well as other features, functions and / or characteristics disclosed herein.

[0069] The following claims particularly point out certain combinations and subcombinations regarded as novel and non-obvious. The claims may refer to "an" element or a "first" element or its equivalent. The claims may be construed to include one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment of the present claims or by presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, are also deemed to be included in the subject matter of the present disclosure.

Claims

1. A method of operating a vehicle, comprising: When the vehicle stops on a first road surface having a first slope greater than a threshold slope, the motor is rotated to a predetermined position. 2 . The method of claim 1 , further comprising not rotating the motor to the predetermined position when the vehicle is parked on a second surface, the second surface having a grade less than a threshold grade.

3. The method according to claim 1, wherein: The predetermined position is a position within a predetermined range of the motor rotor angle position, at which the torque output of the motor is the maximum torque output when the motor is at zero speed. The method according to claim 1 , wherein the motor is a synchronous motor or an induction motor.

5. The method of claim 1, wherein the predetermined position is stored in a memory of a controller, and the first encoder and the second encoder provide data to rotate the motor to the predetermined position.

6. The method of claim 5, wherein the predetermined position is a function of the angle of current supplied to the motor. The method of claim 1 , wherein the first slope is estimated by an inclinometer. 8 . The method of claim 1 , further comprising adjusting a torque output of the electric machine based on a creep torque request, a driver demand torque request, and a brake torque request after rotating the electric machine to the predetermined position.

9. A vehicle system comprising: Electric motors for moving vehicles; The clutch of the transmission system; An inverter, the inverter being electrically connected to the motor; as well as The controller includes executable instructions stored in a non-volatile memory, which enable the controller to adjust the rotational position of the rotor of the motor according to the ground slope when the vehicle is stopped or the starting index when the vehicle is stopped.

10. The vehicle system of claim 9, further comprising additional executable instructions causing the controller to adjust the rotational position of the rotor further in response to the rotational position of the rotor minimizing power loss in the motor when the motor is at zero speed.

11. The vehicle system of claim 9, further comprising additional executable instructions causing the controller to adjust the rotational position of the rotor further in response to the rotational position of the rotor that maximizes the torque output of the motor when the motor is at zero speed.

12. The vehicle system of claim 9, further comprising additional executable instructions causing the controller to apply vehicle brakes when the vehicle is stopped.

13. The vehicle system of claim 12, further comprising additional executable instructions for causing the controller to open the clutch when the vehicle is stopped and the ground level is greater than a threshold, and then adjust the rotational position of the rotor when the vehicle is stopped.

14. The vehicle system of claim 13, wherein the clutch is a dog clutch.

15. The vehicle system of claim 14, wherein the clutch is a friction clutch.

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