Description:TECHNICAL FIELD
[001] This disclosure relates generally to the field of electrical vehicles (EVs), and more particularly, to a method and a system for managing power flow in the EV.
BACKGROUND
[002] Electrical vehicles (EVs) are propelled by an electrical motor, which draws power from a battery. This battery may be charged using an external power source, such as a charging station or a home charging setup. A charging port on the EV allows the battery pack to receive energy from the external power source. This energy stored by the battery pack is then used to power the electrical motor.
[003] At present, the EV may employ a separate on-board charger (OBC) to charge the battery. The OBC may include a separate set of magnetics that may be utilized for charging function. Further, generally, an OBC of high power rating is used in a vehicle to charge the battery in less time. The use of separate OBC with high power rating may not only increase a cost and affordability of a user but may also increase complexities, such as packaging in available space, in the EV. Increasing OBC power output also requires flexibility to interface to AC grid with either 1-ph or 3-phase input.
[004] Furthermore, on-board chargers are expected to manage Bi-directional power flow thus allowing the user to tap electrical energy stored in the vehicle battery and use it for external load applications.
[005] Therefore, there is a requirement to efficiently manage power flow in the EV for charging without implementing any additional high cost and complex power electronics components.
SUMMARY
[006] In an embodiment, a system for managing power flow in an electric vehicle (EV) is disclosed. The system may include a battery and a converter-inverter (CI) circuit to supply alternating current (AC) power to a traction motor from the battery. The system may include a rectifier to receive AC power from an external supply and supply direct current (DC) power to charge the battery through windings of the traction motor and the CI circuit. The system may further include a first phase leg to receive DC power from the battery and supply AC power to a load external to the EV through the CI circuit and bypassing the rectifier. The system may include a controller to control a plurality of contactors to cause power flow through at least one of: the CI circuit, the rectifier, and the first phase leg, to operate the system in one of: a traction mode, a regeneration mode, an AC charging mode, and an external power flow mode.
[007] In another embodiment, a method for managing power flow in an electrical vehicle (EV) is disclosed. The method may include determining, by a controller, a requirement for power flow management in the EV based on at least one of a state of charge (SOC) of a battery, a power demand of the EV, availability of an external power supply, and availability of an external load. The method may further include controlling, by the controller, a plurality of contactors to manage the power flow through at least one of: a converter-inverter (CI) circuit, a rectifier, a first phase leg based on the requirement. In an embodiment, the controlling may cause operation of the EV in one of: a traction mode, a regeneration mode, an AC charging mode, and an external power flow mode.
[008] In yet another embodiment, an electrical vehicle (EV) comprising a controller is disclosed. The vehicle may further include a battery, a converter-inverter (CI) circuit, a rectifier, a first phase leg and a second phase leg. The CI circuit may supply alternative current (AC) power to a traction motor from the battery. The rectifier may receive AC power from an external supply and supply direct current (DC) to charge the battery through windings of the traction motor and the CI circuit. The phase leg may receive DC power from the battery and supply AC power to a load external to the EV through the CI circuit and bypassing the rectifier activate. Further, the controller may control a plurality of contactors to cause power flow through at least one of: the CI circuit, the rectifier, and the phase leg, to operate the EV in one of: a traction mode, a regeneration mode, an AC charging mode, and an external power flow mode.
[009] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[010] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles.
[011] FIG. 1 illustrates a block diagram of a system for managing power flow in an EV, in accordance with an embodiment of the present disclosure.
[012] FIG. 2 illustrates a circuit diagram of a system for managing power flow in an EV, in accordance with an embodiment of the present disclosure.
[013] FIG. 3 illustrates a circuit diagram of a system for managing power flow in an EV, in accordance with another embodiment of the present disclosure.
[014] FIG. 4 illustrates a circuit diagram of a system for managing power flow in an EV, in accordance with yet another embodiment of the present disclosure.
[015] FIG. 5 illustrates a flow diagram of method for managing power flow in an EV, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS
[016] The foregoing description has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which forms the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying other devices, systems, assemblies, and mechanisms for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristics of the disclosure, to its device or system, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
[017] The terms “including”, “comprises”, “comprising”, “comprising of” or any other variations thereof, are intended to cover a non-exclusive inclusions, such that a system or a device that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
[018] Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible, same numerals have been used to refer to the same or like parts. The following paragraphs describe the present disclosure with reference to FIGs. 1 - 5.
[019] An EV is propelled by the traction motor and the charging function of the EV is conventionally performed by a separate on-board charger (OBC). The OBC typically include a separate set of reactive elements that is utilized for charging function, for example, to perform wave-shaping of input AC current so that it closely matches the waveshape and/or frequency of input AC voltage and control of output DC voltage. The use of a separate OBC in the EV may increase a cost and complexity of the system. It is also seen in prior arts that systems that re-use motor windings for charging function may not have wide DC operating voltage range to support battery packs of varying operating voltage range as a result of varying energy sizing and its type of cell selected for vehicle during charging function, thus limiting applicability to vehicle with specific battery operating voltage range. Also, such systems may not interface to three phase AC grid for charging or not allow external power flow mode of wherein the DC power of battery can be used to generate AC power and supply to external loads which is critical requirement in modern day EVs. Therefore, in order to provide solution to the aforementioned problems, the present disclosure propose an efficient system that while utilizing stator windings of the traction motor as boost PFC to perform the wave-shaping of input AC current and control of output DC voltage, thereby eliminating the need for a separate set of reactive elements, also allows to step-down the voltage as per battery voltage requirements to extend the charging function at full power at wide DC operating voltage range, the system furthermore allows external power flow mode wherein the DC power of battery may be used to generate AC power and supply to external loads, furthermore allowing an operating mode of voltage control to regulate the DC-link voltage with respect to battery voltage variation by stepping-up the battery voltage for efficient power flow during traction or to regulate DC charging voltage with respect to battery voltage variation by stepping down the rectified back-emf AC voltage for efficient reverse power flow during regeneration, the said system further allowing an operating mode using phase leg circuit to directly connect the battery across the CI circuit.
[020] The stator windings of the traction motor may be connected to the middle taps of the phases legs of CI circuit. While using the stator windings for the above function, the switches of CI circuit may be adjusted such that the traction motor does not move. Thus, the stator windings not only play a role in movement of the vehicle, but also in charging of the battery. The traction motor may be part of the electric drive unit of the vehicle and may be, for example, a synchronous or asynchronous rotating field machine
[021] To connect the stator windings to a power supply for receiving the power, a single terminal may be extracted from the stator and may be connected to the AC supply. The power supply, which may be an AC supply grid that is available as a 230V single-phase connection or as a 400V three-phase connection, may be connected to the terminal extracted through a rectifier, which may rectify the AC supply into DC. The rectifier may be a diode-based bridge rectifier, that may act as a single-phase or three-phase bridge. In other examples, the rectifier may also include thyristor or any other semiconductor device.
[022] Referring to FIG. 1, a block diagram of a system 100 for managing power flow in an EV is illustrated, in accordance with an embodiment of the present disclosure. The system 100 may include a power management device 102. The power management device 102 may be responsible for managing the power flow within the EV by controlling the contactors and programmable switches in CI circuit and first phase leg. The system 100 may include a battery 104. The battery 104 may act as an energy storage unit in the EV. It may store electrical energy obtained from external power sources, such as charging stations or from regenerative braking mechanism. The battery 104 may provide electrical power to drive an electric traction motor and other electrical and electronic components of the EV. Additionally, the battery 104 may also be allowed to supply power to an external load 118 when required. The external load 118 may be, for example, but not be limited to a grid, another EV, an electrical appliance, a home, or a building.
[023] The system 100 may further include a plurality of contactors 110. The plurality of contactors 110 may be connected to the battery 104. The contactors may be controllable switches that may be activated based on an electrical signal. The plurality of contactors 110 plays a crucial role in regulating power flow within the EV. The power management device 102 may include a controller 106 and a memory 108. In some embodiments, the controller 106 may be an ECU (Electronic Control Unit) of the electric drive unit of the EV or the Vehicle Control unit or combination of both. In an embodiment, the controller 106 may be electrically connected to the plurality of contactors 110. The plurality of contactors 110 may receive electrical pulses from the controller 106 for being turned on and off, to regulate power flow within the EV. The contactors 112 play a role in selecting operating mode of the EV.
[024] The controller 106 may be configured to control the plurality of contactors 110 to cause the power flow through at least one of a converter-inverter (CI) circuit 112, a rectifier 114, and a first phase leg 116. The controller 106 may configure the CI circuit 112 to supply alternating current (AC) power to a traction motor (not shown). Further, the CI circuit 114 may be configured to receive rectified DC power via the rectifier 114 that takes input AC power from an external supply, and supply direct current (DC) power to charge the battery 104 through windings of the traction motor and the CI circuit 112. The rectifier 114 may be a three-phase or single-phase diode-based rectifier. The AC power received may be a single-phase or three-phase AC power. The first phase leg 116 may be configured to receive DC power from the battery 104 and supply AC power to a load external to the EV through the CI circuit 112 and bypassing the rectifier 114.
[025] By controlling the plurality of contactors 110, the controller 106 may operate the system 100 in one of a traction mode, a regeneration mode, an AC charging mode, and an external power flow mode. The controller 106 may select one or more modes based on a requirement for power flow management in the EV. The requirement may be based on at least one of a state of charge (SOC) of the battery 104, a power demand of the EV, availability of an external power supply, and availability of the external load 118. A complete process to operate the system 100 in the one or more modes is explained in greater detail in conjunction with FIG. 2.
[026] In an embodiment, the memory 108 may store instructions that, when executed by the controller 106, cause the controller 106 to perform operation of managing the power flow by controlling the plurality of the contactors 110 in the EV. The memory 108 may be a non-volatile memory or a volatile memory. Examples of non-volatile memory may include, but are not limited to a flash memory, a Read Only Memory (ROM), a Programmable ROM (PROM), Erasable PROM (EPROM), and Electrically EPROM (EEPROM) memory. Examples of volatile memory may include but are not limited to Dynamic Random Access Memory (DRAM), and Static Random-Access memory (SRAM). The memory 108 may store various data (for example, data related to the SOC of the battery 104, the power demand of the EV, availability of the external power supply, and availability of the external load, etc.,) that may be required to operate the system 100.
[027] Now referring to FIG. 2, a circuit diagram 200 of the system 100 for managing power flow in an EV is illustrated, in accordance with an embodiment of the present disclosure. The circuit diagram 200 depicts a connection of various components with a plurality of contactors 110 to manage the power flow in the EV. The plurality of contactors 110 (for example, a K1 contactor, a K2 contactor, a K3 contactor, a K4 contactor, and a K5 contactor) may be used to regulate the power flow through the various components of the circuit, such as the CI circuit 112, the rectifier 114, and the first phase leg 116.
[028] In order to manage the power flow in the EV, the controller 106 may be configured to control the plurality of contactors 110 to cause the power flow through at least one of the CI circuit 112, the rectifier 114, and the first phase leg 116, to operate the system 100 in one of the traction mode, the regeneration mode, the AC charging mode, and the external power flow mode.
[029] In order to operate the system 100 in at least one of the traction mode and the regeneration mode, the controller 106 may control the K1 contactor, connecting the battery 104 and the CI circuit 112, causing power flow between the battery 104 and the traction motor 202. In particular, to enable the system 100 to operate in the traction mode, the controller 106 may activate the K1 contactor to cause the power flow from the battery 104 to the traction motor 202. The activation of the K1 contactor also allows flow of power from the traction motor 202 to the battery 104 during regeneration by the traction motor 202. The controller 106 may turn on the K1 contactor and deactivate the K2 contactor when it is determined that the EV is to be driven, thereby allowing the traction motor 202 to receive power supply and rotate. By deactivating the K2 contactor, the first phase leg is bypassed to avoid any power flow during traction mode and regeneration mode, thus allowing it to be designed at a lower power as per charging requirements.
[030] The CI circuit 112 may typically include three legs of half bridge modules consisting of two semiconductor devices and its associated freewheeling diodes and is designed as per the requirements of electric drive unit. To this end, the semiconductor contactor may be any programmable power contactor such as the IGBT or MOSFET, the selection based on the DC voltage and switching frequency applicability and efficiency criteria in the vehicle. The CI circuit 112 may act as an inverter and a converter. The functionality of the three legs may be determined by a switching pattern applied, serving as either the converter or the inverter, depending on the specific operational requirements. The three legs of the CI circuit 112 may be electrically connected to three-phase stator windings (e.g., L1, L2, and L3) of the traction motor 202. In an embodiment, the CI circuit 112 may be configured to supply electric power to the traction motor 202 from the battery 104. In such embodiment, the CI circuit 112 may act as the DC-AC inverter circuit. The power obtained by the traction motor 202 may drive the EV. In an example, in the traction mode, the operating power may range from 35KW to 150kW.
[031] For the regeneration mode, the controller 106 may enable the system 100 to operate in the regeneration mode by activating the K1 contactor and deactivating the K2 contactor, causing a reverse power flow from the traction motor 202 to the battery 104. The regeneration mode may include a conversion of motor torque into electrical energy when the traction motor 202 is in deceleration state.
[032] For the AC charging mode, the controller 106 may initially determine if the vehicle is connected via the charging port to an external power supply. When the vehicle is connected to the external power supply, the controller 106 may enable the system 100 to operate in the AC charging mode. This may be achieved by activating the K3 contactor and the K2 contactor to cause the power flow from the external supply to the battery 104 through the rectifier 114, the CI circuit 112, the first phase leg 116, and the K2 contactor. In particular, the K3 contactor may connect the positive output of the rectifier to a common terminal N of the traction motor 202, enabling the rectifier 114 to receive AC power from the external supply. The common terminal N may be extracted from the three phase stator windings of the traction motor 202. In an embodiment, the three phase stator windings L1, L2, and L3 of the traction motor 202 are in a star connection.
[033] In an embodiment, the first phase leg 116 may be connected to the CI circuit 112. The first phase leg 116 may include the half bridge module of two semiconductor devices and its associated freewheeling diode. The purpose of phase leg is to support the charging function and is designed as per the requirements of charging power. Further, the first phase leg 116 may include two controllable switches in series that may be controlled by the controller 106. The controllable switches in the first phase leg 116 may be any programmable power switch, such as IGBT or MOSFET. The choice of the programmable power switch may be based on the DC voltage and switching frequency applicability and efficiency criteria during charging. In some embodiments, during the AC charging mode, the controller 106 is to program the controllable switches of the first phase leg 116 such that a low-frequency ripple in DC voltage supplied to the battery is minimized.
[034] Further, the K2 contactor may be connected between the two controllable switches, such as to the middle point of first phase leg and to L4 inductor. Also, the controller 106 enables the AC charging mode by activating the K2 contactor and the K3 contactor.
[035] In an embodiment, the rectifier 114 (for example, a three-phase diode-based rectifier) may be configured to receive AC power from the external supply and supply DC power to charge the battery 104 through the three phase stator windings of the traction motor 202 and the CI circuit 112. In such an embodiment, the CI circuit 112 may act as the converter. In particular, the CI circuit 112 may act as a power factor corrector to convert varying DC power received from the rectifier 114 into pure DC power for charging the battery 104. A condenser may be connected across the rectifier output to absorb ripple current. Further, the rectifier 114 may be connected with an AC and/or EMI(electromagnetic interference) filter 204 at the input side in order to reduce harmonics and/or electromagnetic interferences of the electrical current caused by flow of the electrical power from the external power supply. It is to be noted that the AC power from the external supply may be a single-phase or three-phase supply. The single phase to three phase charging power range from 3.3 kW to 44kW. Moreover, in an example, the battery 104 operating voltage ranges from 200V-500V.
[036] In a more elaborative way, when the DC power generated from the rectifier 114 is supplied to each of the three legs of the CI circuit 116, the CI circuit 116 may serve as a role of interleaved boost power factor corrector (PFC). In this role, the CI circuit 116 may convert the incoming DC power into a pure DC power output. The CI circuit 112 performs wave-shaping of input AC current so that it closely matches the waveshape and/or frequency of input AC voltage and control the output DC voltage. This DC power output may be then supplied to the battery 104 with a selection between the contactor K1 and contactor K2 being determined by specific conditions. For example, if the DC power output from the CI circuit 112 is substantially equal to operating range of the battery 104, the controller 106, in response, may activate the K1 contactor. This allows direct connection of the DC power to the battery 104 to perform the charging operation. However, when the DC voltage output from the CI circuit 112 cannot match the operating voltage of the battery 104 depending on the battery SOC, the controller 106 may activate the K2 contactor. The activation of K2 contactor initiates the supply of controlled DC power to the battery 104 for the charging operation. More specifically, in order to facilitate the controlled DC power, an inductor L4 connected in series with the K2 contactor and the first phase leg 116 may act as step-down converter This arrangement ensures that the voltage of the DC power supply is effectively reduced, either for single-phase or three-phase AC input, allowing it to match wide operating range of voltage of battery 104 which is selected as per vehicle requirements. The DC current flows to the inductor L4 through the contactor K2 and an upper switch 206 of the first phase leg 116. Furthermore, in order to facilitate the controlled DC power, the first phase leg 116 may be advantageously switched to minimize low-frequency ripple in DC charging voltage that is fed to the battery while ensuring the charging current requirements of the battery.
[037] . By way of an example, during AC charging mode when the DC voltage output from the CI circuit 112 (e.g., 390V) is greater than the rated DC power of the battery 104 (e.g., 320V), the first phase leg, the inductor L4 and condenser 302 may act as a step-down converter to reduce the voltage of the DC power to match with the battery rated voltage. In such a case, the K1 contactor remains deactivated, and the DC power flows via the CI circuit 112, the first phase leg 116, the K2 contactor and the inductor L4.
[038] The controller106 may enable the AC charging by controlling operation of the contactor K1 and K2, the CI circuit 112, and the first phase leg 116. For example, the controller 106 may turn on K1 or K2 contactors depending on the DC output of the CI circuit 112 and the operating voltage range of the battery 104.
[039] For the external power flow mode, the controller 106 may initially determine requirement for supplying AC power to a load external to the EV from the battery 104. For this, the controller 106 may check for the availability of the external load 118 (e.g., electrical appliance, another EV, grid, home, building, etc.). It should be noted that the battery 104 may be required to have enough power in order to supply the power to the external load 118. Based on the availability of the external load 118, the controller 106 may further check for the SOC of the battery 104. Accordingly, based on the availability, the controller 106 may enable the system 100 to operate in the external power flow mode. This may be achieved by activating the K1 contactor, the K4 contactor and the K5 contactor in order to cause the power flow from the battery 104 to the external load 118 through the first phase leg 116, the CI circuit 112, and the stator windings of the traction motor 202. In particular, the K4 contactor and the K5 contactor are connectable to the external load 118 and connected to the first phase leg 116.
[040] To elaborate, in the external power flow mode, the K1 contactor is activated to supply the DC power from the battery 104 to the CI circuit 112. Within the CI circuit 112, the DC power get inverted into AC power. To deliver this AC power from the CI circuit 112 to the external load 118 through the traction motor 202, the contactor K4 is activated, creating a bypass route around the rectifier 114. It should be noted that during this process, the contactor K3 remains deactivated. In the return path, the contactor K5 is responsible for carrying current to the two controllable switches in the first phase leg 116. Depending on whether the AC power is in a positive cycle or negative cycle, either of the two controllable switches is turned ON. The external power flow mode may offer a single phase power output of, for example, ranging from 2.5kW to 19.2kW.
[041] The external load 118 may be one of the grid, another EV, electrical appliance, home, or a building. Therefore, the external power flow mode may allow the EV to act as a mobile power source, enabling applications such as running external appliances (V2L), transferring energy to a home or building (V2H/V2B), supplying real and/or reactive power to grid and serving as a backup power source during outages (V2G), and also achieve vehicle-to-vehicle (V2V) charging. This enhances the utility and versatility of the EV.
[042] Referring now to FIG. 3, a circuit diagram 300 of the system 100 for managing power flow in the EV is illustrated, in accordance with another embodiment of the present disclosure. As described earlier in conjunction with previous FIG. 2, the three phase stator windings L1, L2, and L3 of the traction motor (202) are in the star connection. Apart from the star connection, the three phase stator windings L1, L2 and L3 of the traction motor 202 may also be connected in a delta connection.
[043] Therefore, the present FIG. 3 depicts the circuit 300 of an exemplary scenario where the three phase stator windings L1, L2 and L3 of the traction motor 202 is in the delta connection. In an embodiment, the K3 contactor may be connected to the common terminal N extracted from a common point of the windings L1 and L3 of the traction motor (202). Further, the three windings L1, L2 and L3 of the traction motor 202 is connected to the three legs of the CI circuit 112. In order to manage the power flow in the EV, the controller 106 may be configured to control the plurality of contactors 110 to cause the power flow through at least one of the CI circuit 112, the rectifier 114, and the first phase leg 116, in order to operate the system 100 in one of the traction mode, the regeneration mode, the AC charging mode, and the external power flow mode. It should be noted that, for the circuit 300, a similar process may be followed to manage the power flow in the EV as explained earlier for the circuit 200 where the stator windings L1, L2, and L3 of the traction motor (202) are in a star connection.
[044] Referring now to FIG. 4, a circuit diagram 400 of the system for managing power flow in the EV is illustrated, in accordance with yet another embodiment of the present disclosure. There may be a scenario where the battery operating voltage range may be low and required to be stepped-up. The present FIG. 4 depicts the circuit diagram 400 for an exemplary scenario where the voltage of the battery 104 may be stepped-up. This step-up may further be used to flow in one of the traction motor (202) and the external load (118) based on the requirement, leading to better system efficiency of the electric drive unit in the vehicle. To achieve this, the circuit 400 may include a second phase leg 402 that may be connected in parallel to the first phase leg 116 to handle higher power flow from battery. The first phase leg 116 may be connected to a positive terminal of the battery 104 via the K1 contactor. The middle point of the two controllable switches(as explained in FIG.2) is connected to an inductor La (analogous to the inductor L4) that may be connected in series with a K2a contactor (analogous to the K2 contactor).
[045] The second phase leg 402 may also include two controllable switches and the K2b contactor may be connected between the two controllable switches. In particular, the K2b contactor is connected to a middle point of the second phase leg and an inductor Lb is connected in series with the K2b contactor to step-up voltage of battery 104 during traction mode. In some embodiments, the K2b contactor is connected to the middle point of the second phase leg and the inductor Lb is connected in series with the K2b contactor to step-down rectified AC voltage during regeneration mode.
[046] The second phase leg 402 may be connected in parallel of CI circuit 112. The second phase leg 402 may include half bridge module of two semiconductor devices and its associated freewheeling diode. The purpose of second phase leg 402 is, either in combination of first phase leg or not, to support higher power flow from battery to motor in traction mode or from motor to battery in regenerative mode and is designed as per the requirements of traction motor power.
[047] In an embodiment, the first phase leg 116 and the second phase leg 402 may be connected to a condenser 302 that may be connected to the two controllable switches and in parallel with battery 104. The condenser 302 may be included as part of existing DC-link capacitor of the CI circuit with the remaining part connected directly across the CI circuit 112 with purpose of re-using part of the existing condenser to reduce cost and space. The purpose of phase leg circuit is to support charging as well as traction mode of the system.
[048] The system may further include the traction mode of voltage control using phase leg circuit to regulate a DC-link voltage with respect to battery voltage variation by stepping-up the battery voltage for efficient power flow during traction. For example, when the battery voltage is less than required to drive the EV in traction mode or to supply the voltage to the load external 118, then the controller 106 may activate the K2a contactor and the K2b contactor. The activation of K2a contactor and the K2b contactor may lead to stepping-up of power from the battery to the traction motor 202 or to the external load 118. This stepping-up of the voltage by the second phase 302 may ensure the addition in power to fulfill the power demand of the traction motor 202 and the external load 118. The additional power flow from the battery 104 to the external load 118 in the external power flow mode may be supported by an inductor Lx connected between the common terminal of the traction motor 202 and the K3 contactor. In another embodiment, for efficient reverse power flow during regeneration the DC charging voltage is regulated with respect to battery voltage variation by stepping down the rectified back-emf AC voltage. In another embodiment, the switching of two phase legs may be interleaved with respect to each other for better efficiency.
[049] The circuit 400 may further include the rectifier 114 to receive AC power from the external supply and supply direct current (DC) power to charge the battery 104 through windings of the traction motor 202 and the CI circuit 112. Using the first phase leg 116 and the second phase leg 402, the charging power from the CI circuit 112 may either be stepped-down to lower voltage as per battery voltage requirements and the charging power fed to the battery or in other case the charging power output from CI circuit 112 may be directly fed to battery 104.
[050] Referring now to FIG. 5, a flow diagram of a method 500 for managing power flow in an EV is illustrated, in accordance with an embodiment of the present disclosure. It should be noted that the steps 502 – 504 may be performed by the controller 106 of the power management device 102. At step 502 of the method 300, the controller 106 may determine a requirement for power flow management in the EV based on at least one of a SOC of a battery 104, a power demand of the EV, availability of an external power supply, and the availability of an external load 118.
[051] At step 504, the controller 106 may control a plurality of the contactors 110 in order to manage the power flow through at least one of the CI circuit 112, the rectifier 114 and the first phase leg 116. The controlling may cause operation of the EV in one of: a traction mode, a regeneration mode, an AC charging mode, an external power flow mode. In the traction mode, the EV may be driven by the traction motor 202 that may receive AC power from the battery 104 via the CI circuit 112. In the regeneration mode, the reverse power flows from the traction motor 202 to charge the battery 104 during deceleration of the EV.
[052] Further, the controller 106 may activate a K3 contactor and a K2a contactor to operate the EV in the AC charging mode. In this mode, the power may flow from the external supply to the battery 104 through the rectifier 114, the CI circuit 112, and the first phase leg 116 based on the availability of the external power supply. Further, the controller 106 may activate the K1 contactor, a K4 contactor, and a K5 contactor in the external power flow mode. In the external power flow mode, the controller 106 may cause power flow from the battery 104 to the external load 118 through the first phase leg 116, the CI circuit 112, and the traction motor 202. Further, the power supply from the battery 104 to the external load 118 may be based on the availability of the external load and the state of charge SOC of the battery 104.
[053] As will be appreciated by those skilled in the art, the method and system described in the various embodiments discussed above are not routine, or conventional or well understood in the art. The method and system discussed above may provide several advantages. The system may seamlessly integrate the management of power flow in the EVs across different modes, such as the traction mode, the regeneration mode, the AC charging mode, and the external power flow mode. Unlike conventional systems that may require additional components for bidirectional charging functions i.e., the external power flow mode, the described method and system effectively manage the power flow without the need for extra, costly components. This reduction in complexity leads to cost savings in both manufacturing and maintenance.
[054] Further, the system and method provides for combining charging and traction functions in electric vehicle by re-using components of the existing electric drive unit in the vehicle, wherein reverse power flow is made possible in both the functions, leading to effective capture of regenerative energy during braking in the former case and allowing the electric power stored in battery to be used for external-to-vehicle load applications in the latter case.
[055] For example, in the described system, the power flow in the external power flow mode is achieved through a control of a set of contactors, including the K1 contactor, K4 contactor, K5 contactor. These contactors are placed within the circuit and are controlled by the controller. Instead of relying on traditional circuits for external power flow mode, the system uses functionality of these contactors and their placement to facilitate power flow from the battery to the external load, such as the grid or another EV. This not only simplifies the overall system architecture but also enhances the reliability and efficiency of bidirectional charging in the EVs.
[056] Further, the AC charging mode is enabled by activating the K3 contactor and the K2 contactor. The K3 contactor, which connects the rectifier to the common terminal N extracted from the windings of the traction motor, allows the rectifier to receive AC power from the external supply convert it into DC power and supply the DC power to charge the battery through the rectifier, the CI circuit, the phase leg, and the K2 contactor.
[057] Furthermore, the system adapts to a diverse range of external power supplies, accommodating both single-phase and three-phase charging scenarios. This adaptability ensures compatibility with various charging infrastructures, providing users with flexibility and convenience.
[058] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[059] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
[060] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
[061] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
, Claims:I/We Claim:
1. A system (100) for managing power flow in an electric vehicle (EV), comprising:
a battery (104);
a converter-inverter (CI) circuit (112) to supply alternating current (AC) power to a traction motor from the battery (104);
a rectifier (114) to receive AC power from an external supply and supply direct current (DC) power to charge the battery (104) through windings of the traction motor (202) and the CI circuit (112);
a first phase leg (116) to receive DC power from the battery (104) and supply AC power to a load external (118) to the EV through the CI circuit (112) and bypassing the rectifier (114); and
a controller (106) to control a plurality of contactors (110) to cause power flow through at least one of: the CI circuit (112), the rectifier (114), and the phase leg (116), to operate the system (100) in one of: a traction mode, a regeneration mode, an AC charging mode, and an external power flow mode.

2. The system (100) as claimed in claim 1, comprising a K1 contactor connecting the battery (104) and the CI circuit (112), and wherein the controller (106) is to activate the K1 contactor to operate the system (100) in at least one of: the traction mode and the regeneration mode, causing power flow between the battery (104) and the traction motor.

3. The system (100) as claimed in claim 1, comprising a K3 contactor connecting the rectifier (114) and a common terminal extracted from the windings L1, L2, and L3 of the traction motor (202),
wherein the windings L1, L2, and L3 of the traction motor (202) are connected in a star connection, and
wherein the controller (106) is to activate the K3 contactor to enable the rectifier (114) to receive AC power from the external supply.

4. The system (100) as claimed in claim 1, wherein the windings L1, L2, and L3 of the traction motor are connected in a delta connection, and wherein the K3 contactor is connected to the common terminal N extracted from a common point of the windings L1 and L3 of the traction motor (202).

5. The system (100) as claimed in claim 1, wherein the first phase leg (116) comprises two controllable switches in series, wherein a K2a contactor is connected between the two controllable switches, and wherein to enable the AC charging mode, the controller is to activate the K3 contactor and the K2a contactor, to cause power flow from the external supply to the battery through the rectifier (114), the CI circuit (112), the phase leg (116), and the K2a contactor.

6. The system (100) as claimed in claim 5, comprising an inductor La connected in series with the K2a contactor to step down voltage supplied to the battery (104) during the AC charging mode.

7. The system as claimed in claim 6, wherein during the AC charging mode, the controller (106) is to program the controllable switches of the first phase leg (116) such that a low-frequency ripple in DC voltage supplied to the battery is minimized.

8. The system (100) as claimed in claim 1, comprising a second phase leg (402) connected in parallel to the first phase leg (116), wherein a K2b contactor is connected to a middle point of the second phase leg (402) and an inductor Lb is connected in series with the K2b contactor to step-up voltage, wherein the second phase leg in combination with the first phase leg enables processing higher power flow from the battery (104).

9. The system (100) as claimed in claim 1, comprising a K4 contactor and a K5 contactor connectable to an external load (118) and connected to the first phase leg (116), wherein to enable the external power flow mode, the controller (106) is to activate the K1 contactor, the K4 contactor, and the K5 contactor, to cause power flow from the battery to the external load (118) through the phase leg (116), the CI circuit (112), and the traction motor (202).

10. The system (100) as claimed in claim 9, wherein the external load (118) is one of: a grid, an electrical appliance, a home, a building, or another EV.

11. A method (500) for managing power flow in an electric vehicle (EV), comprising:
determining (502), by a controller (106), a requirement for power flow management in the EV based on at least one of a state of charge (SOC) of a battery (104), a power demand of the EV, availability of an external power supply, and availability of an external load (118); and
controlling (504), by the controller (106), a plurality of contactors (112) to manage the power flow through at least one of: a converter-inverter (CI) circuit (202), a rectifier (114), and a first phase leg (116) based on the requirement, wherein the controlling causes operation of the EV in one of: a traction mode, a regeneration mode, an AC charging mode, and an external power flow mode.

12. The method (500) as claimed in claim 11, comprising activating (402), by the controller (106), a K1 contactor connecting the battery (104) and the CI circuit (112) to operate the EV in at least one of: the traction mode and the regeneration mode, causing power flow between the battery (104) and the motor.

13. The method (500) as claimed in claim 11, comprising activating by the controller (106), a K3 contactor connecting the rectifier (114) and a common terminal N extracted from the windings L1, L2, and L3 of the traction motor (202),
wherein the windings L1, L2, and L3 of the traction motor (202) are connected in a star connection, and
wherein the controller (106) is to activate the K3 contactor to enable the rectifier (114) to receive AC power from the external supply.

14. The method (500) as claimed in claim 13, wherein the first phase leg (116) comprises two controllable switches in series, a K2a contactor is connected between the two controllable switches, and an inductor La is connected in series with the K2a contactor to supply controlled DC power to the battery (104), wherein a second phase leg (402) is connected in parallel to the first phase leg (116), and wherein a K2b contactor is connected to a middle point of the second phase leg (402) and an inductor Lb is connected in series with the K2b contactor to step-up voltage of the battery (104) during traction mode or step-down rectified AC voltage during regeneration mode.

15. The method (500) as claimed in claim 14, comprising activating (404), by the controller (106), the K3 contactor and the K2a contactor in the AC charging mode, to cause power flow from the external supply to the battery (104) through the rectifier (114), the CI circuit (112), the first phase leg (116), and the K2a contactor.

16. The method (500) as claimed in claim 11, comprising, activating (406), by the controller (106), the K1 contactor, a K4 contactor, and a K5 contactor in the external power flow mode, to cause power flow from the battery (104) to the external load (118) through the phase leg (116), the CI circuit (112), and the traction motor (202), wherein the K4 contactor and the K5 contactor are connectable to the external load (118) and are connected to the first phase leg (116).

17. An electric vehicle (EV), comprising:
a battery (104);
a converter-inverter (CI) circuit (112);
a rectifier (114);
a first phase leg (116); and
a controller (106), wherein
the CI circuit (112) to supply alternative current (AC) power to a traction motor from the battery (104);
the rectifier (114) to receive AC power from an external supply and supply direct current (DC) to charge the battery through windings L1, L2, and L3 of the traction motor and the CI circuit (112);
the first phase leg (116) to receive DC power from the battery (104) and supply AC power to a load external (112) to the EV through the CI circuit (112) and bypassing the rectifier (114); and
the controller (106) to control a plurality of contactors (110) to cause power flow through at least one of: the CI circuit (112), the rectifier (114), and the first phase leg (116), to operate the EV in one of: a traction mode, a regeneration mode, an AC charging mode, and an external power flow mode.

18. The EV as claimed in claim 17, wherein the first phase leg (116) comprises two controllable switches in series, a K2a contactor is connected between the two controllable switches, and an inductor La is connected in series with the K2a contactor to supply controlled DC power to the battery (104).