DESC:ONBOARD CHARGER FOR ELECTRIC VEHICLES
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202321051266 filed on 31/07/2024, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
The present disclosure generally relates to a charger for an electric vehicle. Particularly, the present disclosure relates to an onboard charging system of an electric vehicle. Furthermore, the present disclosure relates to a method operating an onboard charging system of an electric vehicle.
BACKGROUND
As a result of advancements in technology, environmental concerns, and changing consumer preferences, in recent years the electric vehicles are gaining popularity among consumers for collective or personal mobility. The electric vehicles are equipped with electric motor/motors and other electrical and electronic components that are powered from a power pack in the vehicles. The power pack needs to be electrically recharged once the energy stored in the power pack is depleted. The power pack is charged from a power source that is generally located external to the vehicles.
Conventionally, the electric vehicles are charged at the designated charging stations. Such designated charging stations charge the power pack of the electric vehicle by converting the electrical energy received from the power source (grid) into electrical energy suitable to charge the power pack of the electric vehicle. The designated charging stations have chargers to convert the electrical energy, generally from AC to DC, for charging the power pack of the electric vehicle. The chargers comprise power electronic components for the conversion of the electrical energy. Such chargers are capable of quickly charging the electric vehicle, especially, electric two wheelers, within a couple of hours. However, such designated chargers (offboard chargers) require infrastructure and designated spaces for installation. Moreover, such designated chargers are not always available in the nearby areas of the electric vehicle, when the power pack is depleted. Furthermore, the electric vehicle is required to be driven to the charger, which may not always be convenient for the user of the electric vehicle due to various factors including the depleted power pack.
To overcome the issues with the designated chargers (offboard chargers), the electric vehicles nowadays are equipped with onboard chargers. The onboard chargers have the charging electronics integrated in the electric vehicle itself, wherein the electric vehicle is required to be connected to the power source with the help of a charging cable. The onboard chargers resolve the issue of the availability of the charger, as the electric vehicles with onboard chargers can be connected to any electrical outlet (including domestic or commercial) for charging the power pack of the electric vehicle. The onboard charger would convert the AC power from the electrical outlet, to DC power suitable for charging the power pack of the vehicle. However, the existing onboard chargers provides slow charging to the power pack of the electric vehicle. The electric vehicles have limited space, thus, the onboard chargers also face space constraint due to limited space available in the electric vehicle. Furthermore, the electronic components used in the onboard chargers are small and lower rated due to which the output power of the onboard charger is low leading to slow charging of the power pack of the electric vehicle. It is pertinent to note that the size of the electronic components in the onboard chargers cannot be increased due to the space constraint in the electric vehicles. Moreover, higher rated components capable of delivering more power are also avoided as such increase in power output of the onboard charger would increase the generation of heat by the onboard charger. The existing onboard chargers lack the capability to manage the additional heat generated due to high power operation. Such additional heat may damage the power pack or other components of the electric vehicle. Moreover, the existing onboard chargers operates at low switching frequencies during power conversion leading to higher losses. Furthermore, the onboard charging system redundantly sits in the vehicle while the vehicle is not charging. This increases the cost of the electric vehicle.
Therefore, there exists a need for an improved onboard charging system for an electric vehicle that overcomes one or more problems associated as set forth above.
SUMMARY
An object of the present disclosure is to provide an onboard charging system of an electric vehicle.
Another object of the present disclosure is to provide a method of operating an onboard charging system of an electric vehicle.
In accordance with the first aspect of the present disclosure, there is provided an onboard charging system of an electric vehicle. The system comprises a traction motor, a traction inverter and a control unit. The traction motor comprises a plurality of phases and a secondary tap originating from at least one phase of the plurality of phases. The traction inverter electrically coupled with the traction motor configured to convert AC power into DC power in a charging mode and convert DC power into AC power in a traction mode. The control unit configured to control the operation of the traction motor and the traction inverter in the charging mode and the traction mode.
The present disclosure provides an onboard charging system of an electric vehicle, that utilizes traction motor and traction inverter for charging a battery pack of the electric vehicle. Beneficially, the onboard charging system of the present disclosure comprises a specially designed traction motor that acts as an autotransformer during the charging of the vehicle. The onboard charging system as disclosed in the present disclosure is advantageous in terms of providing onboard fast charging of the power pack with increased efficiency. Furthermore, the onboard charging system as disclosed in the present disclosure is advantageous in terms of delivering higher amount of power to charge the battery pack of the electric vehicle. Beneficially, the charging system of the present disclosure utilizes existing components of the traction system (traction motor and traction inverter) of the vehicle to charge the battery pack of the electric vehicle resulting in resolution of the space constraint of the electric vehicle. Beneficially, onboard charging system of the present disclosure utilizes thermal management system of the traction system during the charging of the battery pack of the electric vehicle, thus, eliminating the need of a separate thermal management system.
In accordance with the second aspect of the present disclosure, there is provided a method of operating an onboard charging system of an electric vehicle. The method comprises detecting AC power at an AC input unit; operating a mode switching unit to configure electrical coupling between a traction motor and a traction inverter for a charging mode; operating the traction motor as an autotransformer to stepdown the AC power received from an external power source; and operating the traction inverter as a rectifier to convert the stepped down AC power into DC power to charge a battery pack of the electric vehicle.
Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments constructed in conjunction with the appended claims that follow.
It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
Figure 1 illustrates a block diagram of an onboard charging system of an electric vehicle, in accordance with an aspect of the present disclosure.
Figure 2 illustrates a flow chart a method of operating an onboard charging system of an electric vehicle, in accordance with another aspect of the present disclosure.
In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated dashed arrow, the non-underlined number is used to identify a general item at which the dashed arrow is pointing.
DETAILED DESCRIPTION
The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
The description set forth below in connection with the appended drawings is intended as a description of certain embodiments of an onboard charging system of an electric vehicle and is not intended to represent the only forms that may be developed or utilized. The description sets forth the various structures and/or functions in connection with the illustrated embodiments; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
The terms “comprise”, “comprises”, “comprising”, “include(s)”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, or system 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 system. In other words, one or more elements in a system or apparatus preceded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings which are shown by way of illustration-specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
The present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the description with unnecessary detail.
As used herein, the terms “electric vehicle”, “EV”, and “EVs” are used interchangeably and refer to any vehicle having stored electrical energy, including the vehicle capable of being charged from an external electrical power source. This may include vehicles having batteries that are exclusively charged from an external power source, as well as hybrid vehicles which may include batteries capable of being at least partially recharged via an external power source. Additionally, it is to be understood that the ‘electric vehicle’ as used herein includes electric two-wheelers, electric three-wheelers, electric four-wheelers, electric pickup trucks, electric trucks, and so forth.
As used herein, the terms “power pack” “battery pack”, “battery”, and “power source” are used interchangeably and refer to multiple individual battery cells connected to provide a higher combined voltage or capacity than a single battery. The power pack is designed to store electrical energy and supply it as needed to various devices or systems. Power pack, as referred herein may be used for various purposes such as power electric vehicles and other energy storage applications. Furthermore, the power pack may include additional circuitry, such as a battery management system (BMS), to ensure the safe and efficient charging and discharging of the battery cells. The power pack comprises a plurality of cell arrays which in turn comprises a plurality of battery cells.
As used herein, the terms “electric motor”, and “traction motor” are used interchangeably and refer to a motor specifically designed with multiple phases and employed for the purpose of propelling a vehicle, such as an electric vehicle. It is to be understood that the traction motors rely on electric power to generate motion and provide the necessary torque to drive the wheels of the electric vehicle.
As used herein, the term “phases” and “plurality of phases” are used interchangeably and refer to winding configuration of an electric motor, wherein the coils are arranged such that it produces a rotating magnetic field when powered by a three-phase alternating current (AC) supply. Each phase of the motor corresponds to a phase of the alternating current wherein all three phases of the alternating current are 120 degrees out of phase with reference to each other. It is to be understood that the start of each phase winding is connected to an AC supply and the end of the phase winding is connected with each other forming a common connection point.
As used herein, the term “secondary tap” refers to a connection point on the motor’s winding that provides a different voltage output from the primary voltage. The secondary tap is located on one phase winding of the motor that may be connected to an AC supply. It is to be understood that the location of the secondary tap on the phase winding is determined during the winding of the motor based on a required voltage output.
As used herein, the term “traction system” and “power train unit” are used interchangeably and refer to the system for propelling the vehicle. The traction system for an electric vehicle comprises at least one of: a traction motor, a traction battery, and a traction inverter. The power train's function is to convert kinetic energy into propulsion motion.
As used herein, the terms “traction inverter”, “converter” and “inverter” are used interchangeably and refer to an electronic device that converts power received from the battery pack to drive the electric vehicle motor. The power converter can change the speed at which the motor rotates by adjusting the frequency of the alternating current.
As used herein, the terms “plurality of phase inverter legs”, “phase inverter leg”, “inverter legs”, and “phase legs” are used interchangeably and refer to individual circuit blocks of the traction inverter which are responsible for converting the DC power into the AC power and/or the AC power into the DC power. It is to be understood that each circuit block converts DC power into one phase of AC power, thus, based on the number of phases required for AC power, the number of phase inverter legs are utilized.
As used herein, the terms “onboard charging system”, “onboard charger” and “charger” are used interchangeably and refers to a system for charging battery pack of the electric vehicle by converting the AC power received from a power supply into suitable DC power. The alternating current (AC) power is received from power source including wall sockets of residential outlets. The onboard charging system eliminates the requirement of any additional charging circuit (electronics) to charge the battery pack of the electric vehicle.
As used herein, the term “rectifier” refers to an electronic component to convert the incoming AC current/ applied AC voltage into a pulsating DC voltage. The rectification bridge includes switches including insulated gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs). The switches are arranged in a bridge configuration. The switching of the state of switches is controlled to rectify the AC input voltage/current waveform.
As used herein, the term “DC link capacitor” refers to the component that stores electrical energy of DC power, during periods of high voltage or power availability to be utilized during periods of lower voltage or power demand of direct voltage.
As used herein, the term “charging mode” refers to a mode of operation of the components of the traction system (traction motor and traction inverter) for charging the battery pack of the electric vehicle. In the charging mode, the electric vehicle is stationary and is connected to an external power source supplying AC power. The traction system converts the AC power received from the external power source into suitable DC power to charge the battery pack of the electric vehicle.
As used herein, the term “traction mode” refers to a mode of operation of the components of the traction system (traction motor and traction inverter) for driving the electric vehicle. In the traction mode, the electric vehicle is moving. In the traction mode, the traction system converts DC power received from the battery pack to AC power for driving the traction motor or converts AC power received from the traction motor (due to regenerative braking) to DC power for charging the battery pack.
As used herein, the term “mode switching unit” refers to a switching assembly that changes electric coupling between the traction motor and the traction inverter in different configurations for specific mode such as charging mode and traction mode. It is to be understood that the mode switching unit may comprise a plurality of switches to change the configuration of the electric coupling between the traction motor and the traction inverter.
As used herein, the term “AC input unit” refers to an electric circuit capable of receiving AC input from an external power source. The AC input unit may comprise a charging port to receive the charging gun that connects the AC input unit with an external power source. Furthermore, the AC input may comprise a one-way switch to prevent the flow of back current during the traction mode.
As used herein, the term “control unit” refers to the component used herein, in the system to control the operation of the traction motor, traction inverter and the mode switching unit. The control unit is a computational element that is operable to respond to and process instructions that control the components of the system. Optionally, the control unit includes a microprocessor and a micro-controller, a complex instruction set computing (CISC) microprocessor, a reduced instruction set (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a digital signal processor, or any other type of processing unit. The control unit may operate based on instructions stored in the memory to process the signal corresponding to power ratings of power pack, executes algorithms, and produces output signals to regulate the switching frequency and duty cycle of switching of the state of switches of the traction inverter and mode switching unit.
As used herein, the term “switches” or “switch” or “pair of switches” of the switching legs refers to power electronics devices that control the flow of electrical current. The switches used herein may be wide bandgap switches that may be made up of wide band gap (WBG) materials like Silicon Carbide (SiC), Gallium Nitride (GaN). The wide bandgap materials have higher bandgap energy that increases the electron mobility and thereby enables faster rate of switching. The faster rate of switching of WBG switches reduces the time spent in the high-power dissipation state and consequently lowers the switching losses The switches may be MOSFETs, IGBTs, transistors, or a combination thereof.
As used herein, the term “gate drivers” refers to electronic components responsible for controlling the switching of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) which forms switches in the traction inverter. It is to be understood that the gate drivers convert the control signal into precise voltage and current pulses required to turn the power electronics switches on and off rapidly.
As used herein, the term “communicably coupled” refers to a communicational connection between the various components of the system. The communicational connection between the various components of the system enables the exchange of data between two or more components of the system.
Figure 1, in accordance with an embodiment, describes an onboard charging system 100 of an electric vehicle. The system 100 comprises a traction motor 102, a traction inverter 104, and a control unit 106. The traction motor 102 comprises a plurality of phases 102a, 102b, 102c and a secondary tap 108 originating from at least one phase of the plurality of phases 102a, 102b, 102c. The traction inverter 104 electrically coupled with the traction motor 102 configured to convert AC power into DC power in a charging mode and convert DC power into AC power in a traction mode. The control unit 106 configured to control the operation of the traction motor 102 and the traction inverter 104 in the charging mode and the traction mode.
The present disclosure provides an onboard charging system 100 of an electric vehicle, that utilizes traction motor 102 and traction inverter 104 for charging a battery pack of the electric vehicle. Beneficially, the onboard charging system 100 of the present disclosure comprises specially designed traction motor 102 that acts as an autotransformer during the charging of the vehicle. The onboard charging system 100 as disclosed in the present disclosure is advantageous in terms of providing onboard fast charging of the battery pack with increased efficiency. Furthermore, the onboard charging system 100 as disclosed in the present disclosure is advantageous in terms of delivering higher amount of power to charge the battery pack of the electric vehicle. Beneficially, the onboard charging system 100 of the present disclosure utilizes the existing components of the traction system (traction motor 102 and traction inverter 104) of the vehicle to charge the battery pack of the electric vehicle resulting in resolution of the space constraint of the electric vehicle. Beneficially, onboard charging system 100 of the present disclosure utilizes thermal management system of the traction system during the charging of the battery pack of the electric vehicle, thus, eliminating the need of a separate thermal management system. Beneficially, the onboard charging system 100 of the present disclosure reduces the redundancy of the electronic components in the electric vehicle, thereby, reducing the cost and complexity of the electric vehicle.
The traction motor 102 comprises a plurality of phases 102a, 102b, 102c and a secondary tap 108 originating from at least one phase of the plurality of phases 102a, 102b, 102c. The secondary tap 108 may originate from the phase 102a of the plurality of phases 102a, 102b, 102c. It is to be understood that the location of the secondary tap 108 may be fixed during the assembly of the traction motor 102 based on the output voltage requirement of the onboard charging system 100.
The traction inverter 104 electrically coupled with the traction motor 102 configured to convert AC power into DC power in a charging mode and convert DC power into AC power in a traction mode. It is to be understood that the traction inverter 104 comprises electronic switches which perform switching operation to convert the AC power into DC power or vice versa.
The control unit 106 configured to control the operation of the traction motor 102 and the traction inverter 104 in the charging mode and the traction mode. It is to be understood that the control unit 106 controls the operation of the electronic switches of the traction inverter 104 to control the operation of the traction motor 102 and the traction inverter 104 in the charging mode and the traction mode. It is to be understood that in the charging mode, the switches of the traction inverter 104 are operated to convert the AC power into DC power for charging the battery pack. Similarly, it is to be understood that in the traction mode, the switches of the traction inverter 104 are operated to convert the DC power received from the battery to three phase AC power for driving the traction motor 102 or to convert the three phase AC power received from the traction motor 102 (due to regeneration) to DC power for charging the battery pack.
In an embodiment, the control unit 106 is configured to detect whether the electric vehicle is stationary to enable the charging mode. Beneficially, the control unit 106 may detect and utilize the position of at least one parking stand to determine whether the electric vehicle is stationary or not. Alternatively, the control unit 106 may utilize any other suitable mechanism to determine whether the electric vehicle is stationary or not. In an embodiment, the control unit 106 may receive at least one user command to enable the charging mode.
In an embodiment, the onboard charging system 100 comprises a mode switching unit 110, wherein the mode switching unit 110 is operated by the control unit 106 to configure electrical coupling between the traction motor 102 and the traction inverter 104 in the charging mode and the traction mode. Beneficially, the mode switching unit 110 re-configures the electrical coupling between the traction motor 102 and the traction inverter 104 according to the charging mode or the traction mode. It is to be understood that the electrical coupling between the traction motor 102 and the traction inverter 104 is single phase electrical coupling in the charging mode. Furthermore, the electrical coupling between the traction motor 102 and the traction inverter 104 is three phase electrical coupling in the traction mode.
In an embodiment, the mode switching unit 110 comprises at least one electrical switch to configure the electrical coupling between the traction motor 102 and the traction inverter 104 in the charging mode and the traction mode. Beneficially, the at least one electrical switch of the mode switching unit 110 re-configure the electrical coupling between the traction motor 102 and the traction inverter 104 in single phase and three phase for charging mode and traction mode respectively.
In an embodiment, each phase of the plurality of phases 102a, 102b, 102c of the traction motor 102 is electrically coupled to a respective phase inverter leg 104a, 104b, 104c of the traction inverter 104 in the traction mode via the mode switching unit 110. Beneficially, the traction motor 102 and the traction inverter 104 operate as three-phase systems in the traction mode.
In an embodiment, the secondary tap 108 and corresponding phase 102a from which the secondary tap 108 is originating are electrically coupled to the respective phase inverter leg 104a, 104b of the traction inverter 104 in the charging mode via the mode switching unit 110. Beneficially, the traction motor 102 and the traction inverter 104 operate as single-phase systems in the charging mode.
In an embodiment, the onboard charging system 100 comprises an AC input unit 112 electrically coupled with two phases 102a, 102c of the traction motor 102 forming a primary winding of an autotransformer with the secondary tap 108 originating from one of the two corresponding phases 102a, 102c forming the primary winding. Beneficially, the AC input unit 112 may comprise an electrical input port (charging port) to receive charging gun. More beneficially, the AC input unit 112 may comprise a switch to reverse flow of current during the traction mode.
In an embodiment, the AC input unit 112 is configured to receive the AC power from an external power source. Beneficially, the AC power received from the external power source is utilized by the system 100 to charge the battery pack of the electric vehicle.
In an embodiment, the control unit 106 is configured to detect the AC power at the AC input unit 112 and operate the mode switching unit 110 to configure the electrical coupling between the traction motor 102 and the traction inverter 104 for the charging mode. Beneficially, the default electrical coupling between the traction motor 102 and the traction inverter 104 is configured for the traction mode. Beneficially, the electrical coupling between the traction motor 102 and the traction inverter 104 is re-configured from the traction mode to the charging mode when the AC power at the AC input unit 112 is detected by the control unit 106. It is to be understood that the control unit 106 may send instruction to the mode switching unit 110 to switch the electrical coupling between the traction motor 102 and the traction inverter 104 from three-phase to single-phase as described above.
In an embodiment, the traction motor 102 acts as the autotransformer to stepdown the AC power received from the external power source and the traction inverter 104 acts as a rectifier to convert the stepped down AC power into the DC power to charge a battery pack of the electric vehicle during the charging mode. Beneficially, the traction motor 102 acting as the autotransformer eliminates the requirement of any additional transformer for charging the battery pack of the electric vehicle. Beneficially, the traction inverter 104 acting as the rectifier eliminates the requirement of any additional power converter for charging the battery pack of the electric vehicle.
In an embodiment, the control unit 106 is configured to operate the mode switching unit 110 to configure the electrical coupling between the traction motor 102 and the traction inverter 104 for the traction mode, when the supply of the AC power from the external power source is terminated. Beneficially, electrical coupling between the traction motor 102 and the traction inverter 104 is configured back for the traction mode once the charging of the battery pack is stopped or terminated.
In an embodiment, the system 100 comprises the traction motor 102, the traction inverter 104, and the control unit 106. The traction motor 102 comprises the plurality of phases 102a, 102b, 102c and the secondary tap 108 originating from at least one phase of the plurality of phases 102a, 102b, 102c. The traction inverter 104 electrically coupled with the traction motor 102 configured to convert AC power into DC power in the charging mode and convert DC power into AC power in the traction mode. The control unit 106 configured to control the operation of the traction motor 102 and the traction inverter 104 in the charging mode and the traction mode. Furthermore, the onboard charging system 100 comprises the mode switching unit 110, wherein the mode switching unit 110 is operated by the control unit 106 to configure electrical coupling between the traction motor 102 and the traction inverter 104 in the charging mode and the traction mode. Furthermore, the mode switching unit 110 comprises at least one electrical switch to configure the electrical coupling between the traction motor 102 and the traction inverter 104 in the charging mode and the traction mode. Furthermore, each phase of the plurality of phases 102a, 102b, 102c of the traction motor 102 is electrically coupled to a respective phase inverter leg 104a, 104b, 104c of the traction inverter 104 in the traction mode via the mode switching unit 110. Furthermore, the secondary tap 108 and corresponding phase 102a from which the secondary tap 108 is originating are electrically coupled to the respective phase inverter leg 104a, 104b of the traction inverter 104 in the charging mode via the mode switching unit 110. Furthermore, the onboard charging system 100 comprises an AC input unit 112 electrically coupled with two phases 102a, 102c of the traction motor 102 forming the primary winding of the autotransformer with the secondary tap 108 originating from one of the two corresponding phases 102a, 102c forming the primary winding. Furthermore, the AC input unit 112 is configured to receive the AC power from the external power source. Furthermore, the control unit 106 is configured to detect the AC power at the AC input unit 112 and operate the mode switching unit 110 to configure the electrical coupling between the traction motor 102 and the traction inverter 104 for the charging mode. Furthermore, the traction motor 102 acts as the autotransformer to stepdown the AC power received from the external power source and the traction inverter 104 acts as the rectifier to convert the stepped down AC power into the DC power to charge a battery pack of the electric vehicle during the charging mode. Furthermore, the control unit 106 is configured to operate the mode switching unit 110 to configure the electrical coupling between the traction motor 102 and the traction inverter 104 for the traction mode, when the supply of the AC power from the external power source is terminated.
In an example, the AC power received at the AC input unit 112 from the domestic power supply is of 230V. The control unit 106 would detect the AC power at the AC input unit 112 and instruct the mode switching unit 110 to re-configure the electrical coupling between the traction motor 102 and the traction inverter 104 for charging mode. Due to the secondary tap 108, AC input power is stepped down to 100V and reaches the traction inverter 104 acting as rectifier. The traction inverter 104 acting as rectifier would convert the stepped down AC power of 100V to DC power of 48V to charge the battery pack. It is to be understood that the exact voltage levels at the output of the traction motor 102 (working as stepdown autotransformer) and traction inverter 104 (working as rectifier) may vary based on the requirement of the battery pack.
Figure 2, describes a method 200 of operating an onboard charging system 100 of an electric vehicle. The method 200 starts at step 202 and finishes at step 208. At step 202, the method 200 comprises detecting AC power at an AC input unit 112. At step 204, the method 200 comprises operating a mode switching unit 110 to configure electrical coupling between a traction motor 102 and a traction inverter 104 for a charging mode. At step 206, the method 200 comprises operating the traction motor 102 as an autotransformer to stepdown the AC power received from an external power source. At step 208, the method 200 comprises operating the traction inverter 104 as a rectifier to convert the stepped down AC power into DC power to charge a battery pack of the electric vehicle.
It would be appreciated that all the explanations and embodiments of the system 100 also apply mutatis-mutandis to the method 200.
In the description of the present invention, it is also to be noted that, unless otherwise explicitly specified or limited, the terms “disposed”, “mounted,” and “connected” are to be construed broadly, and may for example be fixedly connected, detachably connected, or integrally connected, either mechanically or electrically. They may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Modifications to embodiments and combinations of different embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “have”, and “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural where appropriate.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the present disclosure, the drawings, and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.
,CLAIMS:WE CLAIM:
1. An onboard charging system (100) of an electric vehicle, wherein the system (100) comprises:
- a traction motor (102) comprising a plurality of phases (102a, 102b, 102c) and a secondary tap (108) originating from at least one phase of the plurality of phases (102a, 102b, 102c);
- a traction inverter (104) electrically coupled with the traction motor (102) configured to convert AC power into DC power in a charging mode and convert DC power into AC power in a traction mode; and
- a control unit (106) configured to control the operation of the traction motor (102) and the traction inverter (104) in the charging mode and the traction mode.
2. The onboard charging system (100) as claimed in claim 1, wherein the onboard charging system (100) comprises a mode switching unit (110), wherein the mode switching unit (110) is operated by the control unit (106) to configure electrical coupling between the traction motor (102) and the traction inverter (104) in the charging mode and the traction mode.
3. The onboard charging system (100) as claimed in claim 2, wherein the mode switching unit (110) comprises at least one electrical switch to configure the electrical coupling between the traction motor (102) and the traction inverter (104) in the charging mode and the traction mode.
4. The onboard charging system (100) as claimed in claim 1, wherein each phase of the plurality of phases (102a, 102b, 102c) of the traction motor (102) is electrically coupled to a respective phase inverter leg (104a, 104b, 104c) of the traction inverter (104) in the traction mode via the mode switching unit (110).
5. The onboard charging system (100) as claimed in claim 1, wherein the secondary tap (108) and corresponding phase (102a) from which the secondary tap (108) is originating are electrically coupled to the respective phase inverter leg (104a, 104b) of the traction inverter (104) in the charging mode via the mode switching unit (110).
6. The onboard charging system (100) as claimed in claim 1, wherein the onboard charging system (100) comprises an AC input unit (112) electrically coupled with two phases (102a, 102c) of the traction motor (102) forming a primary winding of an autotransformer with the secondary tap (108) originating from one of the two corresponding phases (102a, 102c) forming the primary winding.
7. The onboard charging system (100) as claimed in claim 6, wherein the AC input unit (112) is configured to receive the AC power from an external power source.
8. The onboard charging system (100) as claimed in claim 1, wherein the control unit (106) is configured to detect the AC power at the AC input unit (112) and operate the mode switching unit (110) to configure the electrical coupling between the traction motor (102) and the traction inverter (104) for the charging mode.
9. The onboard charging system (100) as claimed in claim 8, wherein the traction motor (102) acts as the autotransformer to stepdown the AC power received from the external power source and the traction inverter (104) acts as a rectifier to convert the stepped down AC power into the DC power to charge a battery pack of the electric vehicle during the charging mode.
10. The onboard charging system (100) as claimed in claim 1, wherein the control unit (106) is configured to operate the mode switching unit (110) to configure the electrical coupling between the traction motor (102) and the traction inverter (104) for the traction mode, when the supply of the AC power from the external power source is terminated.
11. A method (200) of operating an onboard charging system (100) of an electric vehicle, wherein the method (200) comprises:
- detecting AC power at an AC input unit (112);
- operating a mode switching unit (110) to configure electrical coupling between a traction motor (102) and a traction inverter (104) for a charging mode;
- operating the traction motor (102) as an autotransformer to stepdown the AC power received from an external power source; and
- operating the traction inverter (104) as a rectifier to convert the stepped down AC power into DC power to charge a battery pack of the electric vehicle.