Control system configured to control a rotating electric machine of a battery electric vehicle

Abstract

A control system configured to control a rotary electric machine of a battery electric vehicle (BEV), the control system having one or more microprocessors that execute a low efficiency operating mode for the BEV such that the low efficiency operating mode includes determining a high efficiency mode current command corresponding to operation of a rotor of the rotary electric machine at a commanded torque value at a determined physical rotor angular velocity, and increasing current supplied to the rotary electric machine to a level corresponding to operation of the rotor at the commanded torque value at an angular velocity higher than the determined physical angular velocity.

Description

Technical Field

[0001] This application relates to control systems, and more specifically to control systems included in battery electric vehicles (BEVs). Background Technology

[0002] Modern vehicles are increasingly propelled, entirely or at least partially, by one or more electric motors (also known as rotary motors). Power electronics are able to receive electrical power from the vehicle battery and regulate the current supply to the BEV. BEVs operate in a variety of environments with wide temperature ranges. Power electronics can be assigned the task of optimizing the control of the electric motors on the BEV over a wide temperature range, ensuring that specific performance metrics are met across that range. Ensuring that these performance metrics are feasible at low temperatures is helpful. Summary of the Invention

[0003] In one implementation, a control system configured to control a rotating motor of a battery electric vehicle (BEV) has one or more microprocessors that execute an inefficient operating mode for the BEV, such that the inefficient operating mode includes: determining a high-efficiency mode current command corresponding to operation of the rotating motor's rotor at a determined physical rotor angular velocity at a commanded torque value, and increasing the current supplied to the rotating motor to a level corresponding to operation of the rotor at an angular velocity higher than the determined physical angular velocity at the commanded torque value.

[0004] In another implementation, a control system for a rotating electric motor configured to control a BEV has one or more microprocessors that execute an inefficient operating mode for the BEV, such that the inefficient operating mode includes: determining that the ambient temperature or a portion of the BEV is at or below a predetermined temperature; determining the maximum permissible rotor angular velocity at a commanded torque value; and adding a desired inefficiency amount to a high-efficiency current command value, which is equal to or less than the current command value at the maximum permissible rotor angular velocity at the commanded torque value.

[0005] In another implementation, a control system for a rotating electric motor configured to control a battery electric vehicle (BEV) has one or more microprocessors that execute an inefficient operating mode for the BEV, such that the inefficient operating mode includes: determining that the ambient temperature or a portion of the BEV is at or below a predetermined temperature; determining a high-efficiency d-axis current command for a commanded torque; determining a maximum d-axis current command for the commanded torque; and determining a desired inefficiency amount to be applied to the high-efficiency d-axis current command to generate an inefficient mode current command that is equal to or less than the maximum d-axis current command. Attached Figure Description

[0006] Figure 1 It is a block diagram depicting how battery-electric vehicles are implemented;

[0007] Figure 2 It is a block diagram depicting how a part of the control system is implemented;

[0008] Figure 3 It is a block diagram depicting the implementation of another part of the control system;

[0009] Figure 4 This is another graphical representation depicting how a battery electric vehicle (BEV) operates in a low-efficiency mode; and

[0010] Figure 5 It is a block diagram depicting another implementation of a part of the control system. Detailed Implementation

[0011] The control system is capable of intentionally operating the rotary motor (electric motor) of a battery electric vehicle (BEV) in a low-efficiency mode for use at low temperatures (e.g., <20°C). O Cold start at temperatures exceeding 100 degrees Celsius (C). The low-efficiency mode rapidly increases battery and rotary motor hardware temperatures while maintaining the ability to produce the commanded torque output from the rotary motor. The low-efficiency mode can involve increasing the current flow rate beyond what is typically specified at the commanded torque value.

[0012] Go to Figure 1 The diagram illustrates an implementation of electrical system 10. System 10 includes a power grid 12 and a battery electric vehicle (BEV) 14 capable of receiving electrical power from the power grid 12. The power grid 12 can include a power transmission mechanism and any of a plurality of power generators. A generator (not shown) generates AC power, which can then be transmitted over considerable distances away from the generator for residential and commercial use. The generator can be coupled to the power grid 12, which transmits AC power from the generator to end users, such as residences or businesses.

[0013] BEV 14 includes one or more rotary motors 16 (also referred to as electric motors), each rotary motor 16 comprising a stator having stator windings and a rotor (not shown) capable of angular displacement relative to the stator. In one implementation, the rotary motor 16 is a permanent magnet synchronous motor comprising a rotor having a plurality of angularly spaced permanent magnets. The permanent magnets can be made of any of a variety of different materials, one example being neodymium alloys or other rare earth elements. As noted above, the stator windings are capable of receiving current, the supply of which can be regulated by a control system 18, which causes angular displacement of the rotor relative to the stator. The control system 18 can include a microprocessor and an array of power control electronics that facilitate the operation of the rotary motor 16. These electronics can include an inverter implemented using a plurality of MOSFETs that are switched on and off in the direction of the motor controller according to a programmed sequence and timing to cause angular movement of the rotor. The control system 18 is capable of outputting current commands that regulate the current supplied to the rotary motor 16. As part of a field-oriented control system, the current commands can be divided into orthogonal (I0) q Current command and DC (I) d Current commands. The motor controller can be implemented using one or more microprocessors with input / output and non-volatile memory, where data can be stored and accessed. In addition to the inverter, the control system 18 can also include a DC-DC converter to regulate the voltage level of the electrical power supplied to the motor 16. The control system 18 can also include one or more thermistors for determining the ambient temperature and the temperature of the rotating motor 16.

[0014] BEV service equipment 20 (also referred to as a BEV charging station) is capable of receiving AC power from the power grid 12 and supplying that power to the BEV 14. BEV service equipment 20 may include input terminals for receiving AC power from the power grid 12 and transferring it to an on-board battery charger included on the BEV 14. The on-board battery charger may include an AC / DC inverter, enabling the AC power received from the power grid 12 to be supplied to the vehicle battery 26. Cable 24 may be detachably connected to an electrical outlet on the BEV 14 and electrically link the BEV charging station to the BEV 14, allowing AC power to be transferred between the charging station and the BEV 14. The BEV charging station may be classified as a "Level 2" BEV service equipment that receives 240VAC from the power grid 12 and supplies 240VAC to the BEV 14. In other implementations, the levels of AC power input to and / or output from the charging station may be different.

[0015] The term "battery electric vehicle" or "BEV" can refer to a vehicle that is propelled wholly or partially by a rotating electric motor or electric motor. BEV can refer to electric vehicles, plug-in electric vehicles, hybrid electric vehicles, and battery-powered vehicles. The vehicle battery 26 supplies DC power, converted from AC power, to one or more motors 16 that propel the BEV. As noted above, the control system 18 converts DC power back to AC power to cause angular motion of the rotor relative to the stator. One or more vehicle batteries 26 are rechargeable and, to name just a few, can include lead-acid batteries, nickel-cadmium (NiCd) batteries, nickel-metal hydride batteries, lithium-ion batteries, and lithium polymer batteries. Typical BEV battery voltages are 200 to 800 VDC.

[0016] Go to Figure 2-3 The following shows aspects of the control system 18 in more detail. The control system 18 can include a lookup table (LUT) and a controller, such as a PI controller or a PID controller, for controlling the current supplied to (or less than one) rotating motor 16. The current LUT 50 can receive data including the rotor magnet temperature (T0). mag 52. DC link voltage (V) dc 54. Expected torque (τ) cmd )56 and the commanded low-efficiency mode rotor angular velocity (ω op The input of 58 commands the low-efficiency mode rotor angular velocity (ω). op )58 can be added to the determined physical rotor angular velocity (ω) by changing the allowable change of the rotor angular velocity (Δω) 60. 实际 The low-efficiency mode rotor angular velocity (ω) is determined by 62. op )58 can be set to a speed higher than the physical rotor angular velocity (ω 实际 62, but lower than the maximum value (ω) corresponding to the maximum physical rotor angular velocity. max The value of ) is the expected torque (τ) at the maximum physical rotor angular velocity. cmd This is feasible. These inputs can be used to access the current LUT 50 stored in non-volatile memory and determine the corresponding I. d Current command 64 and I q Current command 66.

[0017] Generally, the low-efficiency mode used for cold starts can be initiated when the ambient temperature, a portion of the rotating motor 16, or both are at or below a predetermined temperature. The control system 18 can then determine the maximum permissible change (Δω) in the commanded rotor angular velocity. max The maximum permissible energy change (Δω) given the rotor angular velocity. maxIt can identify the expected loss or inefficiency, and based on the expected loss, can select values ​​equal to or less than Δω. max The value of Δω is calculated and added to the determined physical rotor angular velocity (ω). 实际 ), to generate a low-efficiency mode rotor angular velocity (ω op 70.

[0018] Figure 3 This describes the implementation of a portion of the control system 18. The control system 18 can include features for determining the maximum allowable change in rotor angular velocity (Δω). max Part 300 and capable of adjusting the loss or inefficiency during inefficient modes and generating I q Current command and I d Another part 310 of the current command. The control system 18, including parts 300 and 310, can be applied to existing BEV control systems, enabling system 18 to use existing high-efficiency dq-current command LUTs. Determine Δω max Able to use relationship ω op (k) = Δω max (k-1)+ω 实际 (k) to find τ' max (k)72 starts, where k relates to the number of executions of the digital control system. The value of the maximum torque can be defined and stored in the peak torque LUT 68. The commanded or desired torque τ can be expressed as... cmd (k)76 divided by τ' max (k)72 determines the ratio (τ') of the commanded or desired torque. 比率 (k))74. τ' 比率 (k)74 can use integral control relative to τ* 比率 (k) 78 adjustment. Integral control output ω * op (k)58 can saturate between 0 and the rotor's maximum operating angular velocity. The maximum change in rotor angular velocity Δω max (k)80 can be obtained from ω op (k)58 minus ω 实际 (k)62 is used to determine this.

[0019] Δω max The value of (k)80 can be changed from the maximum allowable change in the rotor angular velocity (Δω). max Part 300 provides adjustment of loss or inefficiency during cold mode and generates I. q Current command 64 and I d The other part of the current command 66, 310. The commanded loss value P* 损失(k)82 can be provided by a portion of the control system 18 outside of portions 300 and 310. A proportional-integral (PI) controller can transfer P... 损失 (k)84 adjusted to P* 损失 (k) 82. The estimated loss expected and incurred during the inefficient mode can be stored in the control system 18. The control system 18 can limit the output Δω of the PI controller. qd，LUT (k) to maintain at 0 and Δω max Within the range of (k) and derive ω qd，LUT (k) 86. The control system 18 is able to access the LUT to use ω qd，LUT (k) = Δω qd，LUT (k) + ω 实际 (k) to generate the current command value (I*) dq (k))64, 66.

[0020] Figure 4 The relationship between the torque (τ) output by the rotary motor 16 and the angular velocity (ω) of the rotor of the rotary motor 16 is depicted. During high-efficiency mode, the current command I... q and current command I d Based on the determined physical rotor angular velocity (ω) 实际 This is determined by [the specific parameters]. However, when in low-efficiency mode, the current command I [is used]. q and current command I d It can be determined that although the rotor's angular velocity is higher, it is less than ω. max Current command I q and current command I d It can be determined that even though the rotor of the rotating electric motor 16 is not moving at a speed higher than ω 实际 The angular velocity operation, the rotor's angular velocity is also ω. op .

[0021] Figure 5 Another implementation of control system 18' is described. Control system 18' is able to look up the high-efficiency d-axis current command (I) for the current operating conditions in the high-efficiency d-axis current LUT88. d，高，ŋ (k)). The control system 18' can then find the maximum possible d-axis current command (I) for the current operating conditions in the maximum d-axis current LUT 90. d，max (k)). The control system 18' can then include a PI controller 94, which regulates power loss and outputs 0 with ΔI. d，max ΔI between (k) d (k). The control system 18' can then calculate the d-axis current command as I*. d (k) = Id，高，ŋ (k)-ΔI d (k). Then, by changing the high-efficiency d-axis current command, the amount of power loss can be generated by increasing the d-axis command current by an amount higher than the high-efficiency value but less than the maximum possible value. The control system 18' can then, based on the determined d-axis current command (I*), d To find the q-axis current command (I*) q The processor 96 is capable of receiving data including the rotor magnet temperature T. mag (k) DC link voltage V dc (k) Desired torque τ cmd (k) and the determined physical rotor angular velocity (ω) 实际 The input of the control system 18' is capable of including the maximum possible d-axis current LUT, the normal mode (high efficiency) d-axis current LUT, and the q-axis current LUT 92.

[0022] It should be understood that the foregoing description is of one or more embodiments of the invention. The invention is not limited to the specific embodiments disclosed herein, but is instead defined solely by the claims below. Furthermore, except where terms or phrases are expressly defined in the foregoing description, statements contained herein relate to specific embodiments and are not intended to be construed as limiting the scope of the invention or the definitions of the terms used in the claims. Various other embodiments and various changes and modifications to the disclosed embodiments will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to fall within the scope of the appended claims.

[0023] As used in this specification and claims, when used in conjunction with a list of one or more components or other items, the terms “for example,” “for instance,” “like,” “as,” and “similar,” as well as the verbs “comprising,” “having,” “including,” and their other verb forms, shall each be interpreted as open-ended, meaning that the list is not intended to exclude other additional components or items. Other terms shall be interpreted in their broadest reasonable sense unless used in a context that requires a different interpretation.

Claims

1. A control system configured to control a rotary electric machine of a battery electric vehicle, the control system comprising: one or more microprocessors that execute a low efficiency operating mode for a battery electric vehicle, wherein the low efficiency operating mode comprises: determining a high efficiency mode current command corresponding to operation of a rotor of the rotary electric machine at a commanded torque value at a determined physical rotor angular velocity, and increasing current supplied to the rotary electric machine to a level corresponding to operation of the rotor at the commanded torque value at an angular velocity higher than the determined physical angular velocity to intentionally increase a temperature of the rotary electric machine.

2. The control system of claim 1, further comprising a current lookup table for determining the current command.

3. The control system of claim 1, further comprising a torque lookup table for determining a maximum torque value.

4. The control system of claim 1, further comprising determining a rotor magnet temperature.

5. The control system of claim 1, further comprising determining an inverter voltage limit and an inverter current limit.

6. The control system of claim 1, further comprising determining that an ambient temperature or a rotor magnet temperature is below a predetermined temperature threshold.

7. The control system of claim 1, further comprising determining that a vehicle battery temperature is below a predetermined temperature threshold.

8. The control system of claim 1, further comprising determining a ratio of the commanded torque relative to a maximum torque value.

9. A control system configured to control a rotary electric machine of a battery electric vehicle, the control system comprising: one or more microprocessors that execute a low efficiency operating mode for a battery electric vehicle, wherein the low efficiency operating mode comprises: determining that an ambient temperature or a portion of the battery electric vehicle is at or below a predetermined temperature; determining a maximum allowable rotor angular velocity at a commanded torque value; and adding a desired inefficiency amount to a high efficiency current command value that is equal to or less than a current command value at the maximum allowable rotor angular velocity at the commanded torque value.

10. The control system of claim 9, further comprising a current lookup table for determining the current command value.

11. The control system of claim 9, further comprising a torque lookup table for determining a maximum allowable change of the commanded rotor angular velocity.

12. The control system of claim 9, further comprising determining a rotor magnet temperature.

13. The control system of claim 9, further comprising determining an inverter voltage limit and an inverter current limit.

14. The control system of claim 9, further comprising determining that an ambient temperature or a rotor magnet temperature is below a predetermined temperature threshold.

15. The control system of claim 8, further comprising determining a ratio of the commanded torque relative to a maximum torque value.

16. A control system configured to control a rotary electric machine of a battery electric vehicle, the control system comprising: one or more microprocessors to perform a low efficiency operating mode for a battery electric vehicle, wherein the low efficiency operating mode comprises: determining that an ambient temperature or a portion of the battery electric vehicle is at or below a predetermined temperature; determining a high efficiency d-axis current command for a commanded torque; determining a maximum d-axis current command for the commanded torque; determining an amount of desired inefficiency to add to the high efficiency d-axis current command to generate a low efficiency mode current command, the high efficiency d-axis current command to be equal to or less than the maximum d-axis current command.

17. The control system of claim 16, further comprising a current lookup table for determining a maximum d-axis current.

18. The control system of claim 16, further comprising a high efficiency d-axis current lookup table for determining the high efficiency d-axis current command.

19. The control system of claim 16, further comprising a q-axis current lookup table for determining a q-axis current corresponding to an output d-axis current command.

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