Description:SYSTEM AND METHOD FOR MANAGING CURRENT IN AN ELECTRIC VEHICLE
Field of the Invention
[0001] The present disclosure generally relates to electric vehicles and more particularly to a power management system for electric vehicles. Moreover, the present disclosure provides a system and method for managing current in an electric vehicle (EV).
Background
[0002] Generally, electric vehicles (EV) that were previously available in the market were of simple construction and operation. For instance, most EVs (such as electric cars) of yesteryears had only one driving mode and a limited top speed that was significantly under 90 km/h. However, as EV technology evolved and EVs start to become more sophisticated, most modern electric cars are provided with multiple driving modes such as an ‘Eco’ mode that is associated with providing low torque to wheels of the EV, a ‘Sport’ mode that is associated with providing intermediate torque to the wheels of the EV as well as other modes wherein high or very high torque may be provided to the wheels of the EV based on a make and design of the EV. Correspondingly, a significant number of modern EVs can achieve top speeds that are well over 100 km/h, which was unfathomable for the EVs of previous.
[0003] Usually, most modern EVs are provided with a motor controller that controls supply of electric current to the motor to enable the EV to be driven in any one of various driving modes as well as any of the predetermined speeds for that particular driving mode. Such electric current supply is accomplished via use of power switching elements such as, field-effect transistors, etc. However, in such EVs, all the transistors are maintained in an active state irrespective of the driving mode selected for the EV, a speed in which the EV is driven, a load carried by the EV and the like, causing the transistors to become stressed and/or overheated, thereby, leading to damage of the transistors. It will be appreciated that such damage to the transistors may potentially lead to breakdown of supply of electric current to the motor of the EV, possibly causing the EV to stop operating altogether.
[0004] Thus, there remains a need for further contributions in this area of technology. More specifically, a need exists in technology to managing current in an electric vehicle (EV).
Objects of the Invention
[0005] An object of the present invention is to provide an improved current/power management of electric vehicle.
[0006] Another object of the present invention is to improve efficiency of a power converter.
[0007] Yet another object of the present invention is to reduce stress and/or heating of switching elements of a power converter of the power management system.
[0008] Still another object of the present invention is to increase an operating life of the switching elements of power converter and consequently, power management system of electric vehicle.
Summary
[0009] The present disclosure generally relates to electric vehicles and more particularly to a power management system for electric vehicles. Moreover, the present disclosure provides a system and method for managing current in an electric vehicle (EV).
[00010] In an implementation, the present disclosure provides a system for managing current in an electric vehicle (EV). The system may include a battery pack, a motor, a power converter and a control unit. The power converter may be operably coupled to the battery pack and the motor, wherein the power converter comprises a set of switching elements arranged in a parallel configuration, wherein the each of the switching elements is associated with a power rating, wherein the each of the switching elements is configured to operate at a first predetermined range of the power rating. The control unit operably coupled to the power converter, wherein the control unit is configured to: determine an operating current requirement to be provided to the motor based on based on a torque requirement of EV, determine a first number of switching elements to be selected from the set of switching elements, based on the determined operating current requirement, such that each of the determined first number of switching elements is configured to operate at the first predetermined range; and activate the determined first number of switching elements to enable delivery of the determined operating current requirement to the motor.
[00011] In an implementation, the present disclosure provides a method for managing current in an electric vehicle (EV), the method may include: determining, an operating current requirement to be provided to a motor based on based on a torque requirement of EV; determining, a first number of switching elements to be selected from a set of switching elements of a power converter, based on the determined operating current requirement, such that each of the determined first number of switching elements is configured to operate at a first predetermined range; and activating, the determined first number of switching elements to enable delivery of the determined operating current requirement to the motor.
Brief Description of the Drawings
[00012] FIG. 1 shows a prior art power management system for an electric vehicle (EV);
[00013] FIG. 2 shows a schematic of schematic of managing current in an electric vehicle (EV), in accordance with an embodiment of the present disclosure;
[00014] FIG. 3 shows a table illustrating various exemplary driving modes for the EV, torque output from the motor as well as operating current requirement to be provided by the battery pack, in accordance with an embodiment of the present disclosure;
[00015] FIG. 4 shows a top view of an electric scooter having a display, in accordance with an embodiment of the present disclosure;
[00016] FIG. 5 shows a circuit diagram of a power converter, in accordance with an embodiment of the present disclosure;
[00017] FIG. 6 shows a table illustrating exemplary scenarios of selection of switching elements for an electric scooter (such as, the electric scooter of FIG. 4) and an electric car (such as, the electric scooter of FIG. 1), in accordance with an embodiment of the present disclosure; and
[00018] FIG. 7 shows a flowchart of a method of managing power for an EV, in accordance with an embodiment of the present disclosure.
[00019] Fig. 8 represents exemplary efficiency of the power converter in a first switch operating mode and a second switch operating mode, in accordance with an embodiment of the present disclosure.
[00020] Fig. 9 represents exemplary efficiency of the power converter in a third switch operating mode and a fourth switch operating mode, in accordance with an embodiment of the present disclosure.

Detailed Description
[00021] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[00022] The present disclosure generally relates to electric vehicles and more particularly to a power management system for electric vehicles. Moreover, the present disclosure provides a system and method for managing current in an electric vehicle (EV).
[00023] In an implementation, the present disclosure provides a system for managing current in an electric vehicle (EV). The system may include a battery pack, a motor, a power converter and a control unit. The power converter may be operably coupled to the battery pack and the motor, wherein the power converter comprises a set of switching elements arranged in a parallel configuration, wherein the each of the switching elements is associated with a power rating, wherein the each of the switching elements is configured to operate at a first predetermined range of the power rating. The control unit operably coupled to the power converter, wherein the control unit is configured to: determine an operating current requirement to be provided to the motor based on based on a torque requirement of EV, determine a first number of switching elements to be selected from the set of switching elements, based on the determined operating current requirement, such that each of the determined first number of switching elements is configured to operate at the first predetermined range; and activate the determined first number of switching elements to enable delivery of the determined operating current requirement to the motor.
[00024] In an implementation, the present disclosure provides a method for managing current in an electric vehicle (EV), the method may include: determining, an operating current requirement to be provided to a motor based on based on a torque requirement of EV; determining, a first number of switching elements to be selected from a set of switching elements of a power converter, based on the determined operating current requirement, such that each of the determined first number of switching elements is configured to operate at a first predetermined range; and activating, the determined first number of switching elements to enable delivery of the determined operating current requirement to the motor.
[00025] Referring to FIG. 1, there is shown a prior art of power management system 10 for an electric vehicle 101 (interchangeably referred as EV 101). As shown, the power management system 10 may comprise a motor controller 12 comprising a microcontroller 14. The microcontroller 14 can be operably coupled to a gate driver 16. The gate driver 16 may be configured to control a set of switching elements 18A, 18B and 18C corresponding to the three phases of a power converter 112. Further, an operating current passing through the set of MOSFETs 18A, 18B and 18C is supplied to a motor 20 that may provide rotational torque to wheels of the EV 101.
[00026] Referring to FIG. 2, there is shown a schematic of managing current in an electric vehicle (EV) 101, in accordance with an embodiment of the present disclosure. The system 100 may comprise a battery pack 102. The battery pack 102 may be configured to supply the operating current to the various electronic components of EV 101. In one example, the battery pack 102 comprises multiple batteries or batter modules, which may be connected in a series and/or parallel connection, such that each battery comprises multiple cells. Non limiting example of such cell are a NiMH (nickel-metal-hydride) cell, a NiCd (nickel-cadmium) cell, a Li-ion (lithium-ion) cell or a LiPo (lithium-polymer) cell.
[00027] In an embodiment, the system 100 may comprise a motor 104 (interchangeably referred as AC motor 104), which can be adapted to generate torque output to drive EV 101. The motor 104 can be operably coupled to the wheels of EV 101 for supplying the torque output to the wheels such that EV 101 can be driven on roads. Further, the motor 104 may be operably coupled to the battery pack 102, to supply the operating current to the motor 104 such that the motor 104 converts the operating current to torque output that can be provided to the wheels of EV 101. The motor 104 can be selected from a permanent magnet synchronous motor (PMSM), switched reluctance motors (SRM), Asynchronous induction motor, a three-phase alternating current (AC) induction motor, other known electric motor.
[00028] In another embodiment, the system 100 may comprise a throttle sensor 106, which can be adapted to detect a throttle input. During usage, the EV 101 might be driven at different speeds corresponding to various factors such as traffic conditions, length of road on which the EV 101 is being driven, road gradients, flat road, climate conditions and the like. Consequently, a driver of EV 101 may utilize an accelerator pedal or rotate throttle to vary an amount of throttle provided to the EV 101 for varying the driving speed of EV 101. The throttle sensor 106 might enable determination of the throttle input when a change in the throttle input is detected. Alternatively, the throttle sensor 106 can be configured to determine the throttle input after predefined intervals. In one example, the throttle sensor 106 can determine the throttle input after every 5 milliseconds.
[00029] In a preceding embodiment, the vehicle torque requirement can be determined based on a road gradient (which can be determined by utilizing one or more orientation sensors, such as, accelerometer, gyro sensor, inclinometer etc.), which may denote a slope of the road at which EV 101 might be driven. In an exemplary embodiment, road gradient or road driving condition can be evaluated by analysing onboard inclination determination sensor such gyro sensor. If the road possesses a rising slope, a higher throttle input may be required to move forward, wherein the higher throttle input may consequently enhance the vehicle torque requirement. If the road possesses a falling slope, a decrease in the vehicle torque might be required as the EV 101 may move forward with a minimum or no throttle input. In an embodiment, the vehicle torque requirement can be determined based on throttle input sensed by the throttle sensor 106, wherein the throttle input can be responsible to increase or decrease of torque output. If, the throttle sensor 106 senses an increase in the throttle input, a higher amount of operating current requirement may be provided to the motor 104 (for generation of a higher torque output), whereas if the throttle sensor 106 senses a decrease in the throttle input, a lower amount of operating current requirement may be provided to the motor 104 for generation of a lower torque output.
[00030] In an alternate embodiment, the system 100 may comprise a drive mode selector 108 adapted to receive a drive mode input. The EV 101 may enable the drivers to drive the EV 101 in different driving modes, wherein each driving mode corresponds to a different behaviour of the EV 101. For example, the EV 101 can comprise an ‘Economy’ or ‘Eco’ driving mode in which the EV 101 may be driven at a low torque output. However, such low torque output corresponds to a low requirement of operating current to be provided by the battery pack 102 to the motor 104 and thus, the EV 101 can be driven for a comparatively longer distance at a single charge of the battery pack 102. Further, the EV 101 can comprise a ‘Sport’ mode in which the EV 101 can be driven at a high torque output to the motor 104. Consequently, the requirement of operating current to be provided by the battery pack 102 to the motor 104 in ‘Sport’ mode might be higher than that provided during the ‘Eco’ mode and thus, the EV 101 can be driven for a comparatively shorter distance but at higher speed at a single charge of the battery pack 102. It shall be appreciated that the ‘Eco’ and ‘Sport’ driving modes discussed above are merely exemplary and the EV 101 may have various driving modes other than these. For example, the EV 101 may have a ‘Rush’ driving mode in which the EV 101 is driven at an even higher torque output than that in the ‘Sport’ driving mode. The drive mode selector 108 can be implemented as a switch (for example, an analogue or a digital switch) that enables the driver of the EV 101 to vary the driving mode of the EV 101. Drive mode selection can also happen via various other means like on a touch-screen display, touch free voice recognition techniques, etc. Further, each driving mode of the EV 101 may have an associated driving speed range. For example, in the ‘Eco’ mode, the EV 101 may be driven at any speed less than or equal to 80 km/h whereas in the ‘Sport’ mode, the EV 101 may be driven at any speed less than or equal to 114 km/h. Consequently, the driver of the EV 101 may vary the throttle input for reaching speeds less than or equal to the maximum allowable speed corresponding to a particular driving mode. Further, the speed at which the EV 101 can be driven (corresponding to the throttle input) as well as the driving mode of the EV 101 may determine, the torque output required to be provided by the motor 104 and the operating current requirement to be received from the battery pack 102. For example, in the ‘Eco’ driving mode in which the EV 101 can be driven at speeds between 1 km/h and 80 km/h, the torque output that can be provided by the motor 104 can vary between 12 to 15 N-m and the operating current requirement can vary between 150 to 200 A.
[00031] In an exemplary embodiment, the control unit 110 can receive various vehicle driving condition related parameters such as drive mode selection input, throttle input, road gradient information, load condition etc from a vehicle control unit (VCU). The VCU can receive vehicle driving condition related parameters from various onboard hardware such as drive mode selector, weight sensor, throttle sensor, gyro sensor, and the like.
[00032] In an embodiment, each driving mode can correspond to fix number of required switching elements (in active state) to enable transfer of electric energy to the motor. In an exemplary scenario, for electric scooter, “Eco" and “sport” mode may be associated with X1 and X2 number of switching elements. Upon determination any change in driving mode (from “Eco” to “sport” mode), the control unit may enable activation of the X2 number of the switching elements associated to the sport mode. The control unit may select fix number of required switching elements based on the historical data. Alternatively, the control unit may activate or deactivate additional switching elements, based on the determined change in driving mode. An increase in determined load may require activation of the additional switching elements, whereas decrease in the determined load may require deactivation of the additional switching elements, in order to avoid unnecessary power dissipation.
[00033] In an embodiment, the control unit may determine present torque demand or operating current requirement-based on throttle input or change in road, without consideration of driving mode. The control unit may determine first number of switching elements based on the determined present torque. Thus, the present disclosure enables selective activation or deactivation of switching elements (of power converter), independent of pre-defined driving mode.
[00034] Referring to FIG. 3, there is shown a table 300 illustrating various exemplary driving modes for the EV 101, the torque output from the motor 104 as well as operating current requirement to be provided by the battery pack 102, in accordance with an embodiment of the present disclosure. The exemplary mode corresponding to motor torque requirement (Nm) and motor current requirement (A) is applicable only for 48V system vehicle. A person skill in the art can customize the driving mode, corresponding motor torque requirement (Nm) and motor current requirement (A) depending on vehicle, motor capacity, nature of vehicle, battery capacity, and the like.
[00035] Referring back to FIG. 2, the system 100 may comprise a control unit 110 operably coupled to the throttle sensor 106, orientation sensor and the drive mode selector 108. The term ‘control unit 110’ as used throughout the present disclosure relates to a particular configuration of hardware and software that enables management of various operations associated with the EV 101. For example, the control unit 110 manages an amount of operating current to be drawn from the battery pack 102 and provided to the motor 104 as well as various other electronic components of the EV 101. The control unit 110 can be configured to determine vehicle torque requirement based on various indicative parameters of EV 101 operating conditions. Non-limiting example of operating condition indicative parameter may include speed of vehicle, throttle input, road gradient, selected drive mode, load on vehicle or vehicle loading conditions such lightly loaded, medium loaded or heavily loaded, battery remaining SoC, battery charging level, etc. The control unit 110 can be configured to determine an operating current requirement to be provided to each phase of the motor 104 based on the determined vehicle torque requirement. In one example, the control unit 110 can be a microcontroller capable of receiving one or more inputs associated with the EV 101 (such as the throttle input from the throttle sensor 106 and the drive mode input from the drive mode selector 108) to calculate or determine the operating current requirement to be provided to each phase of the motor 104. The microcontroller may comprise a memory comprising stored data corresponding to operating current requirement to be provided to the motor 104 based on the drive mode input and the throttle input. Thus, upon receiving the drive mode input from the drive mode selector 108 and throttle input detected by the throttle sensor 106, the control unit 110 may determine the operating current to be received from the battery pack 102, which can be supplied to the motor 104.
[00036] Moreover, the system 100 may comprise the power converter 112 operably coupled to the battery pack 102 and the motor 104. The operating current supplied by the battery pack 102 may be a direct current (DC). However, for operation of the AC motor 104, the DC is required to be converted to AC. The power converter 112 enables rectification of the DC received from the battery pack 102 to AC, which can be supplied to the motor 104. Further, the power converter 112 may comprise a set of switching elements (not shown in FIG. 2) arranged in a parallel configuration. The set of switching elements enable selective transmission of the operating current from the battery pack 102 to the motor 104. Further, the arrangement of the switching elements in the parallel configuration or H-bridge configuration may ensure that activation or deactivation of one switching element amongst the set of switching elements retains operation of the other switching elements in an unaffected state. In one example, each switching element of the set of switching elements is implemented as insulated-gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET) or any other suitable switching elements. In an embodiment, the power converter 112 can be associated with a cooling arrangement (e.g., cooling fan) to provide efficient heat management.
[00037] Further, each switching element can be associated with a power rating (e.g., peak power rating), which can be a maximum amount of current that can be transmitted through each of the switching element. For example, each switching element may be associated with one of the pluralities of power ratings, such as 50 A, 100 A, 150 A, 75 A depending upon the product specification requirements and application areas. Moreover, each switching element can be configured to operate at a first predetermined range (e.g., nominal power rating)of the power rating. It shall be appreciated that each switching element can operate within or up to the maximum amount of operating current. For example, if the power rating of the particular switching element is 50 A, the same switching element may operate at 50%, which may enable transmission of 25 A operating current. In an embodiment, the first predetermined range can be selected from 40-60%, 55-75%, 60-65%, 50-75% and the like of the power rating. For example, the first predetermined range can be 40%, 41%, 45%, 48%, 50%, 52%, 54%, 56%, 57%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74% and 75% of the power rating. Optionally, the first predetermined range can be higher than 60% of the power rating, such as, 62%, 66%, 70%, 75%, 78% and the like. In alternative embodiment, the peak power rating can be 50% or more than the nominal power rating for example, if nominal power rating of a switching element is 60 A, then the peak power rating can be 90 A or more.
[00038] The system 100 may comprise control unit control unit 110 that can be operably coupled to the power converter 112. The control unit control unit 110 can be a microcontroller chip that can regulate a torque output of the motor 104 based on the operating current supplied to the motor 104 from the battery pack 102 via the power converter 112. control unit As disclosed in detail hereinbefore, the control unit 110 is arranged to determine the operating current requirement to be provided to the motor 104control unit. In one example, let the driving mode selected by the driver of the EV 101 is ‘Sport’ and the throttle input detected corresponds to 50%. In an embodiment, the selected drive mode and throttle input can be communicated to control unit control unit 110. The control unit 110 can be arranged to determine operating current requirement of 140 A from the based on the communicated drive mode and throttle input. Thereafter, the control unit control unit 110 determines number of switching elements to be selected based on the determined operating current requirement, wherein each of the determined switching element operates at the first predetermined range. As disclosed hereinabove, each switching element can be made to operate in different ranges leading to varying efficiencies of the switching elements. In one example, let each switching element be associated with a power rating of 100 A and the first predetermined range for each switching element is selected to be 50%. In such an example, the control unit control unit 110 selects three switching elements for from each leg and from each phase of the power converter 112 to be able to supply a maximum operating current of 150 A to the motor 104. Subsequently, the control unit control unit 110 can be configured to activate the determined number of switching elements to enable delivery of the determined operating current requirement to the motor 104. For example, each side and each phase of the power converter 112 comprises five switching elements, and each switching element is associated with a power rating of 50 A. Further, the first predetermined range for each switching element is selected to be 50% and the drive mode for the EV 101 is selected to be ‘Sport’ mode. In such an example, upon determination of the operating current requirement being 140 A, the control unit control unit 110 selects six switching elements from each side and each phase of the power converter 112 for activation such that a maximum operating current of 150 A can be provided to the motor 104 based on the detected throttle input. Correspondingly, remaining two switching elements from each side and each phase of the power converter 112 are maintained in a deactivated state until a change in driving mode, throttle input, and desired operating mode for the switching element is detected. Thus, the control unit control unit 110 utilizes a minimum (or optimal) number of switching elements to supply operating current to the motor 104. Thus, the present disclosure enables operation of each switching elements at close to its nominal power rating to achieve maximum efficiency to improve overall proficiency of power converter 112.
[00039] Referring now to FIG. 4, there is shown a top view of an electric scooter 400 (interchangeably referred as ES 400) having a display 402, in accordance with an embodiment of the present disclosure. A secondary control unit control unit generates an alert if at least one selected switching element operates at 80-98% of the power rating. It may be noted that operating the switching elements at high-power rating may lead to generation of a high amount of heat, resulting in potential damage of the switching elements and other electronic components of the ES 400 and consequently less efficiency. Further, operating the switching elements at a lower range of the power rating (e.g., close to nominal power rating) may generate lesser heat within the switching elements during operation and consequently, increasing an operating life of the switching elements and other electronic components of the ES 400. Consequently, the secondary control unit may determine if any of the selected switching elements deviates from operating in the first determined range of the power rating. In such an instance, the secondary control unit may generate an alert corresponding to the deviation. For an instance, the alert could comprise a visual indication corresponding to illumination of a red light on a dashboard of the ES 400, presenting a message 404 such as ‘Overheat’ on the display 402 or an audible indication informing the driver of the ES 400 that the ES 400 has been “Overheated” and the like. In such an example, the driver of the ES 400 may be required to halt operation of the ES 400 until the selected switching elements are adequately cooled and they can operate within the first predetermined range of the power rating again.
[00040] Referring now to FIG. 5, there is shown a circuit diagram of a power converter 500 (like the power converter 112), in accordance with an embodiment of the present disclosure. The power converter 500 can be operably coupled to a battery pack 502 (like the battery pack 102 of FIG. 2) and a motor 504 (like the motor 104 of FIG. 2). The power converter 500 may comprise a first phase comprising a first set of switching elements 506, wherein a cumulative power rating of the first set of switching elements 506 in an operating mode is greater than a pre-set limit of a motor power rating of the motor 504. Further, the power converter 500 comprises a second phase comprising a second set of switching elements 508, wherein a cumulative power rating of the second set of switching elements 508 in the operating mode is greater than the pre-set limit of the motor power rating. Moreover, the power converter 500 comprises a third phase comprising a third set of switching elements 510, wherein a cumulative power rating of the third set of switching elements 510 in the operating mode is greater than the pre-set limit of the motor power rating. For example, let the power converter 500 be utilized as a three-phase inverter, wherein the power converter 500 may comprise switching elements corresponding to each phase of the inverter 500. Moreover, in such an example, the power converter 500 may comprise a top side and a bottom side. Consequently, the power converter 500 comprises the switching elements 506A, 508A and 510A corresponding to the top side of the three phases and 506B, 508B and 510B corresponding to the bottom side of the three phases. The switching elements of each phase are alternately switched ON/OFF. For example, switching elements 506A, 508A and 510A can be in OFF position, whenever the switching elements 506B, 508B and 510B are in ON position and a vice versa.
[00041] In one example, the set of switching elements 506A, 508A, 510A, 506B, 508B and 510B may comprise five switching elements each, such as 506A-1, 506A-2 … 506A-5, 508A-1, 508A-2 … 508A-5, 510A-1, 510A-2… 510A-5, 506B-1, 506B-2… 506B-5, 508B-1, 508B-2… 508B-5 and 510B-1, 510B-2… 510B-5. In such an example, if only the switching elements 506A-1, 506B-1, 508A-1, 508B-1, 510A-1 and 510B-1 are activated (in alternative manner), the operating current from the battery pack 502 is passed through the switching elements 506A-1, 506B-1, 508A-1, 508B-1, 510A-1 and 510B-1 and not through the remaining switching elements. Consequently, only a portion of the operating current received from the battery pack 502 is supplied to the motor 504. In case 200 A of operating current (based on determined torque requirement) needs to be supplied to motor 504, control unit (not shown) may select four switching elements for each phase, as each switching element can enable transmission of 50 A of operating current (based on assumption that power rating of each switching element is 100 A).
[00042] Further, the cumulative power rating of each of the first set of switching elements 506A-B in the operating mode, the second set of switching elements 508A-B in the operating mode and the third set of switching elements 510A-B in the operating mode being greater than the pre-set limit of the motor power rating of the motor 504 enables to ensure that there is no deficit in the operating current delivered to the motor 504 during operation of the EV101. For example, when the motor power rating is 300 A The cumulative power rating of each of the first set of switching elements 506A-B in the operating mode, the second set of switching elements 508A-B in the operating mode and the third set of switching elements 510A-B in the operating mode can be 360 A, 370 A, 380 A, 390 A, 400 A and the like.
[00043] In one embodiment, the pre-set limit is selected from 10-40%. For example, the pre-set limit can be 10%, 12%, 15%, 18%, 22%, 26%, 27%, 31%, 34%, 38% or 40%. Optionally, the pre-set limit can be higher than 40%. For example, the pre-set limit can be 42%, 45%, 47% or 50%.
[00044] In a preceding embodiment, the vehicle torque requirement can be determined based on the drive mode input received through the drive mode selector 108, wherein each of the drive mode possess distinct vehicle torque requirement. Each of the drive mode may enable generation of different speeds for driving of the EV 101. In an exemplary aspect, if the drive mode input is ‘Eco’, the vehicle torque requirement may be lesser as compared to the drive mode input selected as "Sports”.
[00045] Referring back to FIG. 1, the EV 101 may comprise a weight sensor (not shown) to determine a load on the EV 101. For example, when the EV 101 is an electric scooter or an electric car, the weight sensor could be operably coupled to wheels of the EV 101 to determine overall load exerted on the EV 101. In another example, when the EV 101 is an electric truck or an electric tractor configured to be coupled to an attachment such as, a truck bed, a trailer, a trolley and the like, the weight sensor could be operably coupled to the attachment (such as, to wheels of the attachment).
[00046] According to an embodiment, the control unit 110 can be configured to utilize the determined load to calibrate the determined operating current requirement so that the EV 101 might be driven at a required speed. It may be noted that a higher determined load may require a higher operating current to be supplied from the battery pack 102 to drive the motor 104. Further, a lower determined load may require a comparatively lower operating current to be supplied from the battery pack 102 to drive the motor 104. Consequently, the control unit 110 enables calibration by increasing or decreasing, the operating current supplied from the battery pack 102 to the motor 104 via the power converter 112. Such an increase or decrease in the operating current can be achieved through activation or deactivation of the switching elements of the power converter 112.
[00047] In a preceding embodiment, the control unit control unit 110 may determine a second number of switching elements to be selected from the set of switching elements, based on the calibrated operating current requirement. In an embodiment, either all selected second number of switching elements can be in a deactivated state prior to the selection or some of the selected second number of switching elements might be in an active state at the time of selection. Each of the selected second number of switching elements may operate at the first predetermined range, thereby enhancing the efficiency of the EV 101. The control unit control unit 110 may activate or deactivate additional switching elements, based on the determined load. An increase in determined load may require activation of the additional switching elements, whereas decrease in the determined load may require deactivation of the additional switching elements, in order to avoid unnecessary power dissipation.
[00048] In one embodiment, the control unit control unit 110 can be associated with a memory (not shown) that is arranged to store a unique identifier code (UIC) corresponding to each switching element. The memory can be implemented, for example as an onboard memory or on a cloud database. The UIC can be a string of alphanumeric characters, a barcode and the like that enables differentiation between each switching element. Further, the UIC is indexed with a historical data comprising a log of an activation time and a deactivation time. For example, the historical data comprising the log can comprise the UIC of switching elements stored with the activation and deactivation times for corresponding switching elements, a duration for which a switching element was maintained in the activated or deactivated state and the like.
[00049] As per an embodiment, the control unit control unit 110 may select the number of switching elements based on the historical data to enable efficient functioning of the power converter 112. The control unit control unit 110 may select the switching elements for activation that have not been recently maintained in an activated state. Such a selection of the switching elements may ensure that overheated or stressed switching elements are not selected for operation. In one example, let the set of switching elements comprises 5 switching elements, out of which 3 of them were recently activated whereas 2 of them were maintained in a deactivated state. Further, 3 switching elements are required to be presently activated for supplying the operating current to the motor 104. In such an example, the control unit control unit 110 may select the 2 switching elements that were maintained in the deactivated state for activation in addition to one of the 3 switching elements that were recently activated. The recently activated switching element can be one that was maintained in a deactivated state for prolonged durations, for example, 2 days.
[00050] Referring to FIG. 6, there is shown a table 600 illustrating exemplary scenarios of selection of switching elements for an electric scooter (such as the electric scooter 400 of FIG. 4) and an electric car (such as, the EV 101 of FIG. 2), in accordance with an embodiment of the present disclosure. The operating current requirement for the ‘Eco’ and ‘Sport’ mode can be 75A and 90A, respectively. The minimum number of switching elements (each having power rating 100A) required for ‘Eco’ mode in operating mode 40% or 60%, can be 2. The minimum number of switching elements (each having power rating 100A) required for ‘Sport’ mode in operating mode 40% can be 3 and for operating mode 60% can be 2. In an exemplary aspect, the EV 101 (having 10 switching elements) operates in ‘Eco’, ‘Sport’ and ‘Rush’ modes, which may require 60%, 70% and 80% of throttle input, respectively. Based on the foreclosed throttle inputs, the operating current requirement may be 200A, 280A and 310A, respectively. To provide 200A operating current, 6 switching elements (each having power rating 100A) may be activated in operating mode 40% and 4 switching elements may be selected in operating mode 60%. To provide 280A operating current, 8 switching elements may be activated in operating mode 40% and 5 switching elements may be selected in operating mode 60%. Finall

Claims
I/we claim:
1. A system (100) for managing current in an electric vehicle (EV) (101), the system (100) comprising:
a battery pack (102);
a motor (104);
a power converter (112) operably coupled to the battery pack (102) and the motor (104), wherein the power converter (112) comprises a set of switching elements arranged in a parallel configuration, wherein the each of the switching elements is associated with a power rating, wherein the each of the switching elements is configured to operate at a first predetermined range of the power rating; and
a control unit (110) operably coupled to the power converter (112), wherein the control unit (110) is configured to:
determine an operating current requirement to be provided to the motor (104) based on a torque requirement of EV (101);
determine a first number of switching elements to be selected from the set of switching elements, based on the determined operating current requirement, such that each of the determined first number of switching elements is configured to operate at the first predetermined range; and
activate the determined first number of switching elements to enable delivery of the determined operating current requirement to the motor (104).
2. The system (100) as claimed in claim 1, wherein the first predetermined range is selected from 40-60% of the power rating.
3. The system (100) as claimed in claim 1, wherein the torque requirement of EV (101) is determined based on at least one selected from:
a throttle input sensed by a throttle sensor (106);
a drive mode input received through a drive mode selector (108); and
a road gradient.
4. The system as claimed in claim 1, wherein the EV (101) comprises a weight sensor to determine a load of the EV (101).
5. The system (100) as claimed in claim 4, wherein the control unit (110) utilizes the determined load to calibrate the determined operating current requirement.
6. The system (100) as claimed in claim 5, wherein the control unit (110) utilizes the calibrated operating current requirement to select a second number of switching elements from the set of switching elements, such that each of the selected second number of switching elements is configured to operate at the first predetermined range.
7. The system (100) as claimed in claim 1, wherein the power converter (104) comprises:
a first phase comprising a first set of switching elements, wherein a cumulative power rating of the first set of switching elements, in the operating mode, is greater than 20% of a motor power rating,
a second phase comprising a second set of switching elements, wherein a cumulative power rating of the second set of switching elements, in the operating mode, is greater than 20% of the motor power rating; and
a third phase comprising a third set of switching elements, wherein a cumulative power rating of the third set of switching elements, in the operating mode, is greater than 20% of the motor power rating, in the operating mode.
8. The system (100) as claimed in claim 1, wherein the control unit (110) is associated with a memory that is arranged to store a unique identifier code (UIC) corresponding to each of the switching elements of the set of switching elements, wherein the UIC is indexed with a historical data comprising a log of an activation time and a deactivation time.
9. The system (100) as claimed in claim 8, wherein the control unit (110) is arranged to select a minimum number of the first number of switching elements and the second number of switching elements from the set of switching elements, based on the historical data.
10. A method (700) for managing current in an electric vehicle (EV) (101), the method comprising:
determining, an operating current requirement to be provided to a motor (104) based on a torque requirement of EV (101);
determining, a first number of switching elements to be selected from a set of switching elements of a power converter, based on the determined operating current requirement, such that each of the determined first number of switching elements is configured to operate at a first predetermined range; and
activating, the determined first number of switching elements to enable delivery of the determined operating current requirement to the motor (104).
11. The method (700) as claimed in claim 10, wherein the first predetermined range is selected from 40-60% of a power rating of the switching element.
12. The method (700) as claimed in claim 10, wherein the torque requirement of EV (101) is determined based on at least one selected from:
a throttle input;
a selected drive mode; and
a road gradient.

SYSTEM AND METHOD FOR MANAGING CURRENT IN AN ELECTRIC VEHICLE
Abstract
The present invention relates to a power management system (100) for electric vehicles (101). The system (100) comprises a battery pack (102), a motor (104), a sensor (106) adapted to detect a throttle input, a drive mode selector (108) adapted to receive a drive mode input and a control unit (110) configured to determine an operating current requirement to be provided to the motor (104) based on a received throttle input and drive mode input. Further, the system (100) comprises a power converter (112) that comprises a set of switching elements such that each switching element is associated with a power rating and configured to operate at a first predetermined range of the power rating. Moreover, the control unit (110) configured to determine number of switching elements to be selected, and activate the determined number of switching elements to enable delivery of the determined operating current requirement to the motor (104).
Fig. 2 , C , C , Claims:Claims
I/we claim:
1. A system (100) for managing current in an electric vehicle (EV) (101), the system (100) comprising:
a battery pack (102);
a motor (104);
a power converter (112) operably coupled to the battery pack (102) and the motor (104), wherein the power converter (112) comprises a set of switching elements arranged in a parallel configuration, wherein the each of the switching elements is associated with a power rating, wherein the each of the switching elements is configured to operate at a first predetermined range of the power rating; and
a control unit (110) operably coupled to the power converter (112), wherein the control unit (110) is configured to:
determine an operating current requirement to be provided to the motor (104) based on a torque requirement of EV (101);
determine a first number of switching elements to be selected from the set of switching elements, based on the determined operating current requirement, such that each of the determined first number of switching elements is configured to operate at the first predetermined range; and
activate the determined first number of switching elements to enable delivery of the determined operating current requirement to the motor (104).
2. The system (100) as claimed in claim 1, wherein the first predetermined range is selected from 40-60% of the power rating.
3. The system (100) as claimed in claim 1, wherein the torque requirement of EV (101) is determined based on at least one selected from:
a throttle input sensed by a throttle sensor (106);
a drive mode input received through a drive mode selector (108); and
a road gradient.
4. The system as claimed in claim 1, wherein the EV (101) comprises a weight sensor to determine a load of the EV (101).
5. The system (100) as claimed in claim 4, wherein the control unit (110) utilizes the determined load to calibrate the determined operating current requirement.
6. The system (100) as claimed in claim 5, wherein the control unit (110) utilizes the calibrated operating current requirement to select a second number of switching elements from the set of switching elements, such that each of the selected second number of switching elements is configured to operate at the first predetermined range.
7. The system (100) as claimed in claim 1, wherein the power converter (104) comprises:
a first phase comprising a first set of switching elements, wherein a cumulative power rating of the first set of switching elements, in the operating mode, is greater than 20% of a motor power rating,
a second phase comprising a second set of switching elements, wherein a cumulative power rating of the second set of switching elements, in the operating mode, is greater than 20% of the motor power rating; and
a third phase comprising a third set of switching elements, wherein a cumulative power rating of the third set of switching elements, in the operating mode, is greater than 20% of the motor power rating, in the operating mode.
8. The system (100) as claimed in claim 1, wherein the control unit (110) is associated with a memory that is arranged to store a unique identifier code (UIC) corresponding to each of the switching elements of the set of switching elements, wherein the UIC is indexed with a historical data comprising a log of an activation time and a deactivation time.
9. The system (100) as claimed in claim 8, wherein the control unit (110) is arranged to select a minimum number of the first number of switching elements and the second number of switching elements from the set of switching elements, based on the historical data.
10. A method (700) for managing current in an electric vehicle (EV) (101), the method comprising:
determining, an operating current requirement to be provided to a motor (104) based on a torque requirement of EV (101);
determining, a first number of switching elements to be selected from a set of switching elements of a power converter, based on the determined operating current requirement, such that each of the determined first number of switching elements is configured to operate at a first predetermined range; and
activating, the determined first number of switching elements to enable delivery of the determined operating current requirement to the motor (104).
11. The method (700) as claimed in claim 10, wherein the first predetermined range is selected from 40-60% of a power rating of the switching element.
12. The method (700) as claimed in claim 10, wherein the torque requirement of EV (101) is determined based on at least one selected from:
a throttle input;
a selected drive mode; and
a road gradient.