Description:TECHNICAL FIELD
[0001] The present invention relates to a regenerative braking control apparatus for vehicles. More particularly, it relates to a system, methods, and apparatus for recirculating and controlling a regenerative current.
BACKGROUND
[0002] In general, an electric vehicle is a vehicle with an electric propulsion system. A electric vehicle utilizes the power generated from a battery of the vehicle or to provide driving force to the vehicle. Nowadays, the electric vehicle uses advanced technologies which improves the efficiency of the vehicle as compared to conventional internal combustion propulsion system. One such technology is a regenerative braking. In regenerative braking, the kinetic energy of the vehicle is converted into electric energy which may be stored in a battery or used to run electrical equipment of the vehicle.
[0003] During a process referred to as regenerative braking in a an electric vehicle powertrain, charging a high-voltage/low voltage battery during vehicle braking collects the potential and kinetic energy stored in the braking vehicle. During the regenerative braking, required wheel braking torque is allocated between friction brakes and the motor, which acts as a generator.
[0004] Regenerative braking is an important part of an EV driving experience. The regenerative braking in EVs is used for recouping energy of a moving vehicle by applying a braking torque on the motor hence converting the kinetic energy of the system into electrical energy. However, in practise regenerative braking in EV is restricted to the lower third of a SOC (State of Charge) (0-80%) because at high SOCs the regenerative current that results from regenerative braking cause the battery terminal voltage to temporarily spike. Cell life as well safety is usually affected by these increased voltages. Thus, most EVs restrict regenerative braking at a higher SOCs. However, restricting regenerative braking results due to the lack of regenerative torque at the wheels it provides an inconsistent ride experience.
[0005] In light of the above-stated discussion, it is the need for solutions around this restriction, by being able to achieve both a controlled regenerative current as well as a consistent ride performance. Therefore, the present invention provides a system and a method for recirculating and controlling a regenerative current for a consistent driving experience and a braking experience at all state of charge (SOCs).
[0006] Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
OBJECT OF THE DISCLOSURE
[0007] A primary objective of the present disclosure is to provide a system for recirculating and controlling a regenerative current to provide a consistent driving experience and a braking experience to a user at any state of charge (SOCs) in an electric vehicle.
[0008] Another objective is to provide a method for recirculating and controlling the regenerative current to provide the consistent driving experience and the braking experience at any state of charge (SOCs).

SUMMARY
[0009] An embodiment of the present invention relates to a system for recirculating and controlling a regenerative current to provide a consistent driving experience and a braking experience to a user at any state of charge (SOCs) in an electric vehicle comprising a drivetrain assembly in the electric vehicle comprises at least one motor position sensors configured with a motor and a motor controller of the electric vehicle to collect motor information, a battery connected at both terminals to the motor controller connected via a plurality of phase cables to the motor of the electric vehicle and an electronic control unit comprises the motor controller associated with the motor to provide a controlled regenerative current for a consistent driving experience, a dissipative current controller configured to dissipate the controlled regenerative current in a motor stator at a torque operating point and an electronic braking controller configured to dissipate and blend the controlled regenerative current into a braking system of the electric vehicle. In particular, the regenerative current is anyone of the controlled regenerative current or a dissipative regenerative current.
[0010] In accordance with an embodiment of the present invention, the motor controller is configured for generating a braking torque within the motor for the braking experience, recirculating the controlled regenerative current within the motor for dissipating excess energy to a plurality of motor coils with simultaneous generation of the braking torque and managing the controlled regenerative current and a regenerative torque by controlling a plurality of switches for the consistent driving experience.
[0011] In accordance with an embodiment of the present invention, the motor controller is configured to calculate the regenerative current requirement for the motor based on the regenerative torque request and a regenerative current limit. Moreover, the motor controller may be a field oriented controller. Further, the field-oriented controller is configured with a current control and torque control. Also, the motor controller sends the controlled regenerative current to the battery.
[0012] In accordance with an embodiment of the present invention, the system comprises a traction motor control shunt bleed resistor, a current sensor for estimating current, a controlled loop is configured to control a torque generated by the motor and a battery return current by modulating a plurality of voltages of different phases of the motor.
[0013] In accordance with an embodiment of the present invention, at least one torque input is provided to the motor controller. In particular, the at least one torque input is a user throttle regeneration torque input, a coasting regeneration input, an active regeneration or any other regeneration input.
[0014] In accordance with an embodiment of the present invention, the regenerative current generates the regenerative/braking torque at a low State of charge (SOCs) and a high State of charge (SOCs). In a high phase regenerative current produces a low regenerative torque.
[0015] Another embodiment relates to a method for recirculating and a regenerative current to provide a consistent driving experience and a braking experience to a user at any state of charge (SOCs) in an electric vehicle comprising steps of obtaining a motor information by at least one of motor position sensors, connecting a battery at both terminals to a motor controller connected via a plurality of phase cables to the motor of the electric vehicle; the electronic control unit performs providing, by the motor controller associated with the motor, a controlled regenerative current for a consistent driving experience, dissipating, by a dissipative current controller, the controlled regenerative current in a motor stator at a torque operating point; and dissipating and blending, by an electronic braking controller, the controlled regenerative current into a braking system of the electric vehicle.
[0016] The motor controller further comprises steps of generating a braking torque within the motor for the braking experience, recirculating the controlled regenerative current within the motor for dissipating excess energy to a plurality of motor coils with simultaneous generation of a torque and managing the controlled regenerative current and a regenerative torque by controlling a plurality of switches for the consistent driving experience.
[0017] These and other aspects herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawing. It should be understood, however, that the following descriptions are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the invention herein without departing from the spirit thereof.
BRIEF DESCRIPTION OF FIGURE
[0018] Having thus described the disclosure in general terms, reference will now be made to the accompanying figure.
[0019] Fig. 1A is a block diagram illustrating various components of a system for recirculating and controlling a regenerative current for a consistent driving and braking experience in accordance with an embodiment of the invention;
[0020] Fig. 1B is a schematic diagram illustrating a system architecture for recirculating and controlling regenerative current for the consistent driving and braking experience in accordance with an embodiment of the invention;
[0021] Fig. 1C is a pictorial snapshot illustrating a drivetrain of an electric vehicle in accordance with an embodiment of the present invention;
[0022] Fig. 1D is a block diagram illustrating recirculating and controlling regenerative current for consistent driving experience by the motor controller in accordance with another embodiment of the present invention;
[0023] Fig. 2A, Fig. 2B and Fig. 2C are schematic snapshots illustrating a flow of regenerative current in accordance with one or more embodiments of the present invention;
[0024] Fig. 3 is a flowchart illustrating a method for recirculating and controlling a regenerative current in accordance with an embodiment of the present invention;
[0025] Fig. 4 is a flowchart illustrating a method for recirculating a regenerative current in accordance with an embodiment of the present invention.
[0026] It should be noted that the accompanying figure is intended to present illustrations of a few examples of the present disclosure. The figure is not intended to limit the scope of the present disclosure. It should also be noted that the accompanying figure is not necessarily drawn to scale.
DETAILED DESCRIPTION
[0027] In the following detailed description of the invention, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be obvious to a person skilled in the art that the invention may be practiced with or without these specific details. In other instances, well known methods, procedures and components have not been described in detail so as not to unnecessarily obscure aspects of the invention. Furthermore, it will be clear that the invention is not limited to these alternatives only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art, without parting from the scope of the invention.
[0028] The accompanying drawing is used to help easily understand various technical features and it should be understood that the alternatives presented herein are not limited by the accompanying drawing. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawing. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
[0029] Conditional language used herein, such as, among others, "can," "may," "might," "may," “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain alternatives include, while other alternatives do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more alternatives or that one or more alternatives necessarily include logic for deciding, with or without other input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular alternative. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.
[0030] Terms controlled regenerative current is battery regenerative current and controlled regenerative current can be used interchangeably throughout for convenience.
[0031] Fig. 1A is a block diagram 100 and Fig. 1B 100 is a system architecture illustrating various components of a system for recirculating and controlling regenerative current for a consistent driving and braking experience at any state of charge (SOCs) in an electric vehicle in accordance with an embodiment of the invention. The system 100 comprises at least one motor position sensors 105 configured with a motor 110 and a motor controller 115 of the electric vehicle to collect a motor information, a battery 120 connected at both terminals to the motor controller 115 connected via a plurality of phase cables to the motor 110 of the electric vehicle and an electronic control unit 125 comprises the motor controller 115 associated with the motor 110 to provide a controlled regenerative current for the consistent driving experience, a dissipative current controller 130 configured to dissipate the controlled regenerative current in a motor stator at a torque operating point and an electronic braking controller 135 configured to dissipate and blend the controlled regenerative current into a braking system of the electric vehicle. In particular, the regenerative current is anyone of the controlled regenerative current or a dissipative regenerative current.
[0032] In accordance with an embodiment of the present invention, the motor controller 115 is configured for generating a braking torque within the motor 110 for the braking experience, recirculating the controlled regenerative current within the motor 110 for dissipating excess energy to a plurality of motor coils with simultaneous generation of the braking torque and managing the controlled regenerative current and a regenerative torque by controlling a plurality of switches for the consistent driving experience.
[0033] In accordance with an embodiment of the present invention, at least one torque input is provided to the motor controller 115. In particular, the at least one torque input is a user throttle regeneration torque input, a coasting regeneration input, an active regeneration or any other regeneration input.
[0034] In accordance with an embodiment of the present invention, the motor controller 115 is configured to calculate a regenerative current requirement for the motor 110 based on a regenerative torque request and a regenerative current limit.
[0035] Fig. 1C is a pictorial snapshot illustrating a drivetrain of the electric vehicle in accordance with an embodiment of the present invention. In particular, the battery 120 is connected via the B+, B- terminals to the motor controller 115 which is connected via phase cables to the motor 110. Further, the maximum voltage allowed at battery terminals during charge or discharge is Vmax, which is the max allowable current to control the degradation of the battery. During discharge this is defined as:
Vt = Vcell - I*R
[0036] During charge and regeneration, this is defined as
Vt = Vcell + I*R, f
[0037] It is inferred that the voltage during the charge increases as the amount of regenerative current increases. Further, this may go beyond the max allowable voltage threshold. Thus, at high SOCs large regenerative currents are not allowed.
[0038] Further, the amount of regenerative current is also related to the amount of braking torque felt by the user, reducing the amount of regenerative current affects the ride behavior due to loss of braking torque. Thus, the regenerative current recirculated within the motor 110 also generates the braking torque for the consistent driving experience.
[0039] In accordance with an alternative embodiment of the present invention, the system 100 comprises a traction motor control shunt bleed resistor, a current sensor for estimating current, a controlled loop is configured to control a torque generated by the motor 110 and a battery return current by modulating a plurality of voltages of different phases of the motor 110. The shunt resistor is configured to ensure that the regenerative current is not sent back to the battery 120 for the consistent driving experience.
[0040] Fig. 1D is a diagram 100 for recirculating and controlling regenerative current for consistent driving experience by the motor controller 115 in accordance with another embodiment of the present invention. The motor controller 115 may be a field-oriented controller. Further, the field oriented controller computes the required currents for the motor 110 based on both the regenerative torque request and the regenerative current limit. The field oriented controller is configured with a current control and torque control. Also, the motor controller 115 sends the controlled regenerative current to the battery 120. Further, the field oriented controller is configured to simultaneously satisfy the regenerative current and torque requirement.
[0041] Fig. 2A, Fig. 2B and Fig. 2C are schematic snapshots illustrating a flow of the regenerative current in accordance with one or more embodiments of the present invention. The regenerative current is anyone of the controlled regenerative current 205 or the dissipative regenerative current 210. Moreover, the regenerative current generates the regenerative/braking torque at a low State of charge (SOCs) and a high State of charge (SOCs). Further, high phase regenerative current produces a low regenerative torque.
[0042] Fig. 3 is a flowchart illustrating a method for recirculating and controlling a regenerative current in accordance with an embodiment of the present invention. The method provides a consistent driving experience and a braking experience to a user at any state of charge (SOCs) in an electric vehicle.
[0043] At step 305, a motor information is obtained by at least one of motor position sensors. The motor position sensor is configured with a motor 110 and a motor controller 115 of the electric vehicle.
[0044] At step 310, a battery 120 is connected at both terminals to the motor controller 115 connected via a plurality of phase cables to the motor 110 of the electric vehicle.
[0045] At step 315, performing by an electronic control unit to provide by the motor controller 115 associated with the motor 110, a controlled regenerative current for the consistent driving experience.
[0046] At step 320, a dissipative current controller (130) dissipates the controlled regenerative current in a motor stator at a torque operating point.
[0047] At step 325, by an electronic braking controller (135) dissipates and blends, the controlled regenerative current into a braking system of the electric vehicle.
[0048] Fig. 4 is a flowchart illustrating a method for recirculating a regenerative current in accordance with an embodiment of the present invention. The method 400 starts at step 405-410. The motor controller 115 is associated with the motor 110 to provide a controlled regenerative current for the consistent driving experience.
[0049] At step 405, a braking torque is generated within the motor 110 for the braking experience.
[0050] At step 410, the controlled regenerative current is recirculated within the motor 110 for dissipating excess energy to a plurality of motor coils with simultaneous generation of a braking torque.
[0051] At step 415, the controlled regenerative current and the regenerative torque is managed by controlling a plurality of switches for the consistent driving experience.
[0052] According to an embodiment of the present disclosure, the method guarantees maximum limit on regenerative current in the electric vehicle while honouring user torque request. Further, the method recirculates regenerative current within the motor 100 and dissipating the energy on the motor coils by avoiding the need to send large currents back to the battery and simultaneously achieving the desired braking torque for a consistent ride and braking experience over all SOC ranges.
[0053] While the detailed description has shown, described, and pointed out novel features as applied to various alternatives, it can be understood that various omissions, substitutions, and changes in the form and details of the devices or algorithms illustrated can be made without departing from the scope of the disclosure. As can be recognized, certain alternatives described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others.
[0054] The disclosures and the description herein are intended to be illustrative and are not in any sense limiting the invention, defined in scope by the following claims.
, Claims:We claim, 1. A system for recirculating and controlling a regenerative current to provide a consistent driving experience and a braking experience to a user at any state of charge (SOCs) in an electric vehicle, wherein the system (100) comprising:
a drivetrain assembly in the electric vehicle comprising:
at least one motor position sensors (105), configured with a motor (110) and a motor controller (115) of the electric vehicle to collect motor information;
a battery (120) connected at both terminals to the motor controller (115) connected via a plurality of phase cables to the motor (110) of the electric vehicle;
an electronic control unit comprising:
the motor controller (115) associated with the motor (110) to provide a controlled regenerative current for the consistent driving experience by:
generating a braking torque within the motor (110) for the braking experience;
recirculating the controlled regenerative current within the motor (110) for dissipating excess energy to a plurality of motor coils with simultaneous generation of the braking torque; and
managing the controlled regenerative current and the regenerative torque by controlling a plurality of switches for the consistent driving experience;
a dissipative current controller (130) configured to dissipate the controlled regenerative current in a motor stator at a torque operating point;
an electronic braking controller (135) configured to dissipate and blend the controlled regenerative current into a braking system of the electric vehicle.
2. The system (100) as claimed in claim 1, wherein the motor controller (115) is configured to calculate a regenerative current requirement for the motor (110) based on a regenerative torque request and a regenerative current limit.
3. The system (100) as claimed in claim 1, wherein the system (100) comprises a traction motor control shunt bleed resistor.
4. The system (100) as claimed in claim 1, wherein at least one torque input is provided to the motor controller (115).
5. The system (100) as claimed in claim 1, wherein the at least one torque input is a user throttle regeneration torque input, a coasting regeneration input, an active regeneration or any other regeneration input.
6. The system (100) as claimed in claim 1, wherein the regenerative current generates the regenerative/braking torque at a low State of charge (SOCs) and a high State of charge (SOCs).
7. The system (100) as claimed in claim 1, wherein a high phase regenerative current produces a low regenerative torque.
8. The system (100) as claimed in claim 1, wherein the regenerative current is anyone of the controlled regenerative current or a dissipative regenerative current.
9. The system (100) as claimed in claim 1, wherein the motor controller (115) is a field-oriented controller.
10. The system (100) as claimed in claim 9, wherein the field-oriented controller is configured with a current control and a torque control.
11. The system (100) as claimed in claim 1, wherein the motor controller (115) sends the controlled regenerative current to the battery (120).
12. The system (100) as claimed in claim 1, wherein the system (100) comprises a current sensor for estimating current.
13. The system (100) as claimed in claim 1, wherein the system (100) comprises a controlled loop is configured to control a torque generated by the motor (110) and a battery return current by modulating a plurality of voltages of different phases of the motor (110).
14. A method for recirculating and a regenerative current to provide a consistent driving experience and a braking experience to a user at any state of charge (SOCs) in an electric vehicle comprising steps of:
obtaining a motor information by at least one of motor position sensors (105), wherein the at least one of motor position sensor (105) is configured with a motor (110) and a motor controller (115) of the electric vehicle;
connecting a battery (120) at both terminals to the motor controller (115) connected via a plurality of phase cables to the motor (110) of the electric vehicle;
an electronic control unit performs:
providing, by the motor controller (115) associated with the motor (110), a controlled regenerative current for the consistent driving experience; wherein the motor controller (115) further configured for:
generating a braking torque within the motor (110) for the braking experience;
recirculating the controlled regenerative current within the motor (110) for dissipating excess energy to a plurality of motor coils with simultaneous generation of a torque; and
managing the controlled regenerative current and a regenerative torque by controlling a plurality of switches for the consistent driving experience;
dissipating, by a dissipative current controller (130), the controlled regenerative current in a motor stator at a torque operating point; and
dissipating and blending, by an electronic braking controller (135), the controlled regenerative current into a braking system of the electric vehicle.
15. The method as claimed in claim 14, wherein the motor controller (115) is configured to calculate a regenerative current requirement for the motor (110) based on a regenerative torque request and a regenerative current limit.
16. The method as claimed in claim 14, wherein the method comprises a traction motor control shunt bleed resistor.
17. The method as claimed in claim 14, wherein at least one torque input is provided to the motor controller (115).
18. The method as claimed in claim 17, wherein the at least one torque input is a user throttle regeneration torque input, a coasting regeneration input, an active regeneration or any other regeneration input.
19. The method as claimed in claim 14, wherein the regenerative current generates a regenerative braking torque at a low State of charge (SOCs) and a high State of charge (SOCs).
20. The method as claimed in claim 14, wherein a high phase regenerative current produces a low regenerative torque.
21. The method as claimed in claim 14, wherein the regenerative current is anyone of the controlled regenerative current and a dissipative regenerative current.
22. The method as claimed in claim 14, wherein the motor controller (115) is a field oriented controller.
23. The method as claimed in claim 22, wherein the field oriented controller is configured with a current control and a torque control.
24. The method as claimed in claim 14, wherein the motor controller (115) sends the controlled regenerative current to the battery (120).
25. The method as claimed in claim 14, wherein a controlled loop is configured to control a torque generated by the motor (110) and a battery return current by modulating a plurality of voltages of different phases of the motor (110).