Description:FIELD OF INVENTION
[0001] Embodiments of the present disclosure relate to the field of charging electric vehicles (EV), and more particularly an assembly for charging multiple electric vehicles concurrently and a method thereof.
BACKGROUND
[0002] The popularity of electric vehicles has increased due to advancements in the auto industry, particularly in India. These vehicles, powered by an electric motor, have fewer moving parts, lower operating costs, and are environmentally friendly as they do not use fossil fuels like petrol, diesel, or gasoline. The electricity used to power the motor is typically stored in an on board battery.
[0003] Further, electric vehicles like buses and trucks require charging stations on long routes. These stations may have capacities ranging from 100 kilowatts to 300 kilowatts and may be capable of charging multiple trucks simultaneously, as charging takes time. Total power required at charging stations is high and can be in the range of 1 Megawatt to 4 Megawatt, the supply for which is mostly brought to the charging site as a high voltage supply. Most of the current designs use individual chargers fed with three-phase low voltage (220 volts to 440 volts), which is first rectified to a DC voltage. This DC voltage is converted to a high frequency AC supply that is fed to a high-frequency transformer. The output of the high frequency transformer is rectified and fed to the trucks' batteries. This design ensures high impedance isolation from the power transformer. It also requires a large number of components and has multiple stages of power conversion.
[0004] Hence, there is a need for an improved system for charging an electric vehicle and a method thereof which addresses the aforementioned issue(s). The proposed method reduces the number of power conversion stages and the electronic (power and control) components considerably, thereby increasing the efficiency, reducing the cost significantly and increasing the mean time between failures (MTBF) considerably.
OBJECTIVE OF THE INVENTION
[0005] An objective of the invention is to charge a plurality of electric vehicles simultaneously to the required voltage using buck converters placed in a plurality of charging units.
[0006] Another objective of the invention is to minimize a plurality of harmonics at a direct current bus by coupling a harmonic cancellation unit to tertiary winding, thereby minimizing harmonics at both primary winding injected into the supply lines.
[0007] Yet, another objective of the invention is to substantially reduce need for heat removal from the individual chargers by placing the high-power rectifier within the high voltage transformer positioned in a high voltage yard.
[0008] An objective of the invention is to optimize design of large multi-port charging stations by achieving isolation from main supply within the high voltage transformer itself.
[0009] Another objective of the invention is to minimize voltage loss during transmission from a central rectifier to the individual charging stations by employing direct current distribution as compared to distributing power through AC lines.
BRIEF DESCRIPTION
[0010] In accordance with an embodiment of the present disclosure, an assembly for charging multiple electric vehicles concurrently is provided. The assembly includes a transformer-rectifier unit installed in a high-tension transformer yard adapted to produce a direct current bus as an output to charge a plurality of electric vehicles wherein the transformer-rectifier unit includes a primary winding, a secondary winding, and a tertiary winding. The primary winding is arranged in a delta configuration and adapted to receive a high voltage alternating current from a power source as an input. Further, the secondary winding is arranged in delta-star configuration wherein the delta-star configuration of the secondary winding is connected to a twelve-pulse rectifier to generate the direct current bus that is fed to an individual charging stations. Furthermore, the tertiary winding is arranged in the star configuration adapted to provide current as a feedback to a grid to compensate for a plurality of harmonics generated at a charging station by utilizing a harmonic compensator, wherein the harmonic compensator is of suitable low voltage that feeds the tertiary winding through which the compensation is fed to the grid through the primary winding. Moreover, the assembly includes a plurality of charging units operatively coupled to the transformer-rectifier unit wherein the plurality of charging units is connected to the direct current bus configured to charge the plurality of electric vehicles to a required output charging voltage in a closed loop control, wherein each of the plurality of charging units includes a buck converter to step-down voltage to required voltage to charge the plurality of electric vehicles, wherein each of the plurality of charging units is operatively coupled to a communication interface wherein the communication interface is configured to communicate with an individual battery management unit in each of the plurality of electric vehicles to regulate the required voltage thereby charging the plurality of electric vehicles.
[0011] In accordance with another embodiment of the present disclosure, a method to operate charging multiple electric vehicles concurrently is provided. The method includes producing, by a transformer-rectifier unit, a direct current bus as an output to charge a plurality of electric vehicles wherein the transformer-rectifier unit includes a primary winding, a secondary winding, and a tertiary winding. The method also includes receiving, by the primary winding of the transformer-rectifier unit, a high voltage alternating current from a power source as an input. Further, the method includes generating, by the secondary winding of the transformer-rectifier unit, the direct current bus that is fed to an individual charging stations. Furthermore, the method includes compensating, by the tertiary winding of the transformer-rectifier unit, current as a feedback to a grid to compensate a plurality of harmonics generated at a charging station by utilizing a harmonic compensator, wherein the harmonic compensator is of suitable low voltage that feeds the tertiary winding through which the compensation is fed to the grid through the primary winding, wherein the primary winding is adapted to accommodate and manage effects of the plurality of harmonics. Moreover, the method includes charging, by a plurality of charging units, the plurality of electric vehicles to a required output charging voltage in a closed loop control. Additionally, the method includes converting, by a buck converter of the plurality of charging units, to step-down voltage to required voltage to charge the plurality of electric vehicles. The method includes communicating, by a communication interface, with an individual battery management unit in each of the plurality of electric vehicles to regulate the required voltage thereby charging the plurality of electric vehicles.
[0012] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional specificity and detail with the appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:
[0014] FIG. 1 is a schematic representation of an assembly for charging multiple electric vehicles concurrently in accordance with an embodiment of the present disclosure; and
[0015] FIG. 2 illustrates a flow chart representing the steps involved in a method to operate charging multiple electric vehicles concurrently in accordance with an embodiment of the present disclosure.
[0016] Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
DETAILED DESCRIPTION
[0017] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure.
[0018] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or subsystems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other devices, sub-systems, elements, structures, components, additional devices, additional sub-systems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.
[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.
[0020] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
[0021] In accordance with an embodiment of the present disclosure, an assembly for charging multiple electric vehicles concurrently is provided. The assembly includes a transformer-rectifier unit installed in a high-tension transformer yard adapted to produce a direct current bus as an output to charge a plurality of electric vehicles wherein the transformer-rectifier unit includes a primary winding, a secondary winding, and a tertiary winding. The primary winding is arranged in a delta configuration and adapted to receive a high voltage alternating current from a power source as an input. Further, the secondary winding is arranged in the delta -star configuration wherein the delta - star configuration of the secondary winding is connected to an twelve-pulse rectifier to generate the direct current bus that is fed to an individual charging stations. Furthermore, the tertiary winding is arranged in the star configuration adapted to provide current as a feedback to a grid to compensate a plurality of harmonics generated at a charging station by utilizing a harmonic compensator, wherein the harmonic compensator is of suitable low voltage that feeds the tertiary winding through which the compensation is fed to the grid through the primary winding, wherein the primary winding includes a harmonic cancellation unit adapted to accommodate and manage effects of the plurality of harmonics generated at the direct current bus. Moreover, the assembly includes a plurality of charging units operatively coupled to the transformer-rectifier unit wherein the plurality of charging units is connected to the direct current bus configured to charge the plurality of electric vehicles to a required output charging voltage in a closed loop control, wherein each of the plurality of charging units includes a buck converter to step-down voltage to required voltage to charge the plurality of electric vehicles, wherein each of the plurality of charging units is operatively coupled to a communication interface wherein the communication interface is configured to communicate with an individual battery management unit in each of the plurality of electric vehicles to regulate the required voltage thereby charging the plurality of electric vehicles.
[0022] FIG. 1 is a schematic representation of an assembly for charging multiple electric vehicles concurrently in accordance with an embodiment of the present disclosure. Examples of the plurality of electric vehicles (115) includes, but is not limited to, motorcycles, cars, heavy vehicles like trucks, and buses. The assembly (100) includes a transformer-rectifier unit (105) and a plurality of charging units (160).
[0023] Further, the transformer-rectifier unit (105) installed in a high-tension transformer yard adapted to produce a direct current bus (110) as an output to charge plurality of electric vehicles (115). The high-tension transformer yard is a substation facility that houses and supports transformers, switchgear, and other components for managing transmission and distribution of electricity at high voltage levels. Typically, the transformer-rectifier unit (105) is a device that combines functions of a transformer and a rectifier. The transformer is an electrical device that change voltage level of an alternating current (AC) while maintaining the frequency of the AC signal. The transformer includes two coils of wire, primary coil, and secondary coil, connected by a magnetic core. When an AC voltage is applied to the primary coil, it induces a voltage in the secondary coil, allowing for voltage transformation. Further, a rectifier converts AC into direct current (DC) by allowing current to flow in one direction, essential for converting AC power from the electrical grid into DC power required for electronic devices. When combined, the transformer-rectifier unit (105) steps down or steps-up voltage and converts AC voltage to DC voltage. Specifically, the transformer-rectifier unit (105) includes a primary winding (120), a secondary winding (125), and a tertiary winding (130).
[0024] Furthermore, the primary winding (120) is arranged in a delta configuration and adapted to receive a high voltage alternating current from a power source as an input. Typically, the primary winding (120) is a coil configured in delta configuration refers to arrangement of the primary winding (120) in a closed loop connected to the power source or input side of the transformer, which receives electrical energy and produces a magnetic field when alternating current flows through it.
[0025] Moreover, the secondary winding (125) is arranged in the delta - star configuration. Typically, the secondary winding (125) is a coil on the output side of a transformer, receives magnetic field generated by the primary winding (120) and inducts a voltage, typically connected to the load or device requiring electrical power. The delta - star configuration of the secondary winding (125) is connected to an twelve-pulse rectifier (150) to generate the direct current bus (110) that is fed to an individual charging stations. As used herein, the direct current bus (110) is a common electrical conductor used to distribute the direct current to said plurality of charging units (160), serving as a central pathway for the flow of electrical energy between different components or modules.
[0026] Additionally, the tertiary winding (130) is arranged in the star configuration adapted to provide current as a feedback to a grid to compensate for a plurality of harmonics generated at a charging station by utilizing a harmonic compensator. The harmonic compensator is of suitable low voltage that feeds the tertiary winding (130) through which the compensation is fed to the grid through the primary winding (120). The primary winding (120) includes a harmonic cancellation unit (145) adapted to accommodate and manage effects of the plurality of harmonics generated at the direct current bus (110).
[0027] In one embodiment, the tertiary winding (130) is designed to mitigate harmonics, unwanted frequency components introduced by non-linear loads into power system, by providing a path for the flow of compensating harmonic currents, preventing their impact on the grid.
[0028] Further, the assembly (100) includes a plurality of charging units (160) operatively coupled to the transformer-rectifier unit (105). The plurality of charging units (160) is connected to the direct current bus (110) configured to charge plurality of electric vehicles (115) to a required voltage. Each of the plurality of charging units (160) includes a buck converter (140) to step-down voltage to required output charging voltage to charge the plurality of electric vehicles (115) in a closed loop control. As used herein, the buck converter, also known as a step-down converter, is a DC-DC power converter that efficiently reduces voltage by converting a higher DC voltage into a lower DC voltage using a switch mode power supply topology. Each of the plurality of charging units (160) is operatively coupled to a communication interface. The communication interface is configured to communicate with an individual battery management unit in each of the plurality of electric vehicles (115) to regulate the required voltage thereby charging the plurality of electric vehicles (115). Typically, the communication interface is a mechanism for data exchange between devices buck converter (140) and battery management system), involving physical connectors, protocols, and rules that govern the exchange of information.
[0029] FIG. 2 illustrates a flow chart representing the steps involved in a method to operate charging multiple electric vehicles concurrently. Further, the method (300) includes receiving, by the primary winding of the transformer-rectifier unit, a high voltage alternating current from a power source as an input in step 310. Typically, the power source for transformer-rectifier unit is usually an AC power supply, which generates a magnetic field around the primary winding, which then induces a voltage in the secondary winding via electromagnetic induction.
[0030] The method (300) includes producing, by a transformer-rectifier unit, a direct current bus as an output to charge a plurality of electric vehicles wherein the transformer-rectifier unit includes a primary winding, a secondary winding, and a tertiary winding in step 320.
[0031] In one embodiment, the direct current bus is common to the plurality of charging units.
[0032] Further, the method (300) also includes generating, by the secondary winding of the transformer-rectifier unit, the direct current bus that is fed to an individual charging stations in step 330.
[0033] In one embodiment, the secondary winding of the transformer-rectifier unit compensates for low-ripples on the direct current bus.
[0034] In another embodiment, the secondary winding is configured to generate the direct current bus coupled to photo voltaic cell and battery storage systems.
[0035] In another embodiment, the high-power rectifier is oil-cooled to have an simple, economical and effective heat dissipation. Oil cooling is a method of dissipating the heat from an electrical systems using a circulating liquid. Mineral or synthetic oil is utilized as a cooling medium.
[0036] In one embodiment, an impingement cooling unit is coupled to the individual buck converters to provide effective heat dissipation. As used herein, the impingement cooling unit is a method of directing a liquid or gas to cool electronics components such as microprocessors or power electronics to dissipate heat.
[0037] Furthermore, the method (300) includes compensating, by the tertiary winding of the transformer-rectifier unit, a plurality of harmonics generated at a charging station by utilizing a harmonic compensator, wherein the harmonic compensator is of suitable low voltage that feeds the tertiary winding through which the compensation is fed to the grid through the primary winding, wherein the primary winding includes a harmonic cancellation unit adapted to accommodate and manage effects of the plurality of harmonics generated at the direct current bus in step 340.
[0038] In one embodiment, the tertiary winding is adapted to supply the high voltage alternating current to a plurality of loads wherein the plurality of loads includes heating, ventilation and air conditioning, lighting, canteen, and pumps.
[0039] Moreover, the method (300) includes charging, by a plurality of charging units, the plurality of electric vehicles to a required output voltage in a closed loop control in step 350.
[0040] Additionally, the method (300) includes converting, by a buck converter of the plurality of charging units, to step-down voltage to required voltage to charge the plurality of electric vehicles in step 360.
[0041] Further, the method (300) includes communicating by a communication interface with an individual battery management unit in each of the electric vehicles to regulate the required voltage thereby charging the plurality of electric vehicles in step 370.
[0042] Various embodiments of the assembly for charging multiple electric vehicles concurrently and a method thereof as described above provide the plurality of charging units (160) via the direct current bus (110) thereby low cost due to common DC bus. The buck converter (140) is used in the plurality of charging units (160) to regulate the required output voltage thereby lowering switching frequency, and significantly minimizes switching devices, power conversion stages. In such applications switching frequency normally used is much lower compared to designs involving high frequency transformer and rectifier units used in conventional EV charging units. This results in much lower switching losses and consequently improved efficiency. Furthermore, impingement cooling is a method for effectively cooling buck converters. Further, the harmonic cancellation unit (145) is introduced at the primary winding (120) to minimize unwanted harmonic impact on the grid. Further, the twelve-pulse rectifier (150) is oil-cooled, reliable, and efficient heat-removable system that may be housed outside in a power transformer tank, which is then placed in a high voltage yard, thereby significantly reducing heat dissipation in each of the plurality of chargers.
[0043] The techniques described in this disclosure may be implemented, at least in part, in hardware, software, firmware, or any combination thereof. For example, various aspects of the described techniques may be implemented within one or more processors, including one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components. The term “processor” or “processing subsystem” may generally refer to any of the foregoing logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry. A control unit including hardware may also perform one or more of the techniques of this disclosure.
[0044] Such hardware, software, and firmware may be implemented within the same device or within separate devices to support the various techniques described in this disclosure. In addition, any of the described units, modules, or components may be implemented together or separately as discrete but interoperable logic devices. Depiction of different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be realized by separate hardware, firmware, or software components. Rather, functionality associated with one or more modules or units may be performed by separate hardware, firmware, or software components, or integrated within common or separate hardware, firmware, or software components.
[0045] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the disclosure and are not intended to be restrictive thereof.
[0046] While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.
[0047] The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, the order of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts need to be necessarily performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.
, Claims:1. An assembly (100) for charging multiple electric vehicles concurrently comprising:
characterized in that,
a transformer-rectifier unit (105) installed in a high-tension transformer yard adapted to produce a direct current bus (110) as an output to charge a plurality of electric vehicles (115) wherein the transformer-rectifier unit (105) comprises a primary winding (120), a secondary winding (125), and a tertiary winding (130),
wherein the primary winding (120) is arranged in a delta configuration and adapted to receive a high voltage alternating current from a power source as an input,
wherein the secondary winding (125) is arranged in the delta -star configuration wherein the delta - star configuration of the secondary winding (125) is connected to twelve-pulse rectifier (150) to generate the direct current bus (110) that is fed to an individual charging stations, and
wherein the tertiary winding (130) is arranged in the star configuration adapted to provide current as a feedback to a grid to compensate a plurality of harmonics generated at a charging station by utilizing a harmonic compensator, wherein the harmonic compensator is of suitable low voltage that feeds the tertiary winding (130) through which the compensation is fed to the grid through the primary winding (120), wherein the primary winding (120) comprises a harmonic cancellation unit (145) adapted to accommodate and manage effects of the plurality of harmonics generated at the direct current bus (110);
a plurality of charging units (160) operatively coupled to the transformer-rectifier unit (105) wherein the plurality of charging units (160) is connected to the direct current bus (110) configured to charge the plurality of electric vehicles (115) to a required output charging voltage in a closed loop control,
wherein each of the plurality of charging units (160) comprises a buck converter (140) to step down voltage to required voltage to charge the plurality of electric vehicles (115),
wherein each of the plurality of charging units (160) is operatively coupled to a communication interface wherein the communication interface is configured to communicate with an individual battery management unit in each of the plurality of electric vehicles (115) to regulate the required voltage thereby charging the plurality of electric vehicles (115).
2. The assembly (100) as claimed in claim 1, wherein the tertiary winding (130) is adapted to supply the high voltage alternating current to a plurality of loads wherein the plurality of loads comprises heating, ventilation and air conditioning, lighting, canteen, and pumps.
3. The assembly (100) as claimed in claim 1, comprising an impingement cooling unit coupled to the buck converter to provide effective heat dissipation.
4. The assembly (100) as claimed in claim 1, wherein the twelve-pulse rectifier (150) is placed in a high voltage yard to provide effective and economical oil cooling and reduce heat to be dissipated in the individual chargers by avoiding the twelve-pulse rectifier in the individual chargers.
5. The assembly (100) as claimed in claim 1, wherein the twelve-pulse rectifier (150) is oil-cooled to minimize the heat to be dissipated in the individual charger and provide an economical and effective cooling medium to ensure the heat dissipation.
6. The assembly (100) as claimed in claim 1, wherein the twelve-pulse rectifier (150) is common to the plurality of charging units (160).
7. The assembly (100) as claimed in claim 1, wherein the secondary winding (125) of the transformer-rectifier unit (105) compensates for low ripples on the direct current bus (110).
8. The assembly (100) as claimed in claim 1, wherein the secondary winding (125) is configured to generate the direct current bus (110) coupled to photo voltaic cell and battery storage systems.
9. A method (300) to operate charging multiple electric vehicles concurrently comprising:
characterized in that,
receiving, by the primary winding of the transformer-rectifier unit, a high voltage alternating current from a power source as an input; (310)
producing, by a transformer-rectifier unit, a direct current bus as an output to charge a plurality of electric vehicles wherein the transformer-rectifier unit comprises a primary winding, a secondary winding, and a tertiary winding; (320)
generating, by the secondary winding of the transformer-rectifier unit, the direct current bus that is fed to an individual charging stations; (330)
compensating, by the tertiary winding of the transformer-rectifier unit, a plurality of harmonics generated at a charging station by utilizing a harmonic compensator, wherein the harmonic compensator is of suitable low voltage that feeds the tertiary winding through which the compensation is fed to the grid through the primary winding, wherein the primary winding comprises a harmonic cancellation unit adapted to accommodate and manage effects of the plurality of harmonics generated at the direct current bus; (340)
charging, by a plurality of charging units, the plurality of electric vehicles to a required output charging voltage in a closed loop control; (350)
converting, by a buck converter of the plurality of charging units, to step-down voltage to required voltage to charge the plurality of electric vehicles; (360) and
communicating, by a communication interface, with an individual battery management unit in each of the plurality of electric vehicles to regulate the required voltage thereby charging the plurality of electric vehicles. (370)
Dated this 05th day of December 2024
Signature

Gokul Nataraj E
Patent Agent (IN/PA-5309)
Agent for the Applicant