DESC:ONBOARD CHARGER FOR ELECTRIC VEHICLE
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202321090111 filed on 30/12/2023, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
The present disclosure generally relates to an onboard charger for electric vehicles. Particularly, the present disclosure relates to an onboard charger for waking up and charging a deep discharged battery of an electric vehicle.
BACKGROUND
As a result of advancements in technology, environmental concerns, and changing consumer preferences, in recent years 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.
The power pack of the electric vehicle is managed by a controller that is commonly called a battery management system (BMS). The battery management system calculates various parameters for managing the battery by collecting various information (a battery voltage, a battery current, a battery temperature, state of charge, state of health, etc.). Furthermore, the battery management system manages the power supply to the electrical components of the electric vehicle from the power pack of the electric vehicle. Presently, the electric vehicles are provided with a vacation mode function, to be activated when the vehicle is not to be used for a prolonged period. In such situation, user can activate the vacation mode and then the battery management system will enter a sleep mode, to maintain the state of charge of the power pack and prevent the deep discharge of the power pack. However, the user operation is required to activate the vacation mode in the vehicle which increases the dependency of the battery management system on the user to maintain the state of charge of the battery or prevent deep discharge.
Furthermore, the self-discharging of the power pack is caused when the user forgets to turn on the vacation mode during non-operational conditions of the vehicle for a long time. The self-discharging of the battery for a long time decreases the state of charge of the battery below a specific level which results in deep discharge of the power pack and failure of the operational functionality of the electric vehicle.
When a battery enters a deep discharge state, where battery voltage drops significantly below the normal operating range, it often requires a high inrush current to begin the recharging process. This is because the battery's internal voltage is low, and the charging system needs to compensate for the voltage gap. Further, most modern charging systems are provided with overcurrent protection mechanism, designed to prevent excessive current draw during charging. If the initial charging current exceeds a certain threshold, the overcurrent protection will be triggered to avoid damage to the battery or charging circuit. In the battery’s attempt to recharge, the initial current required to overcome the deep discharge state may cause the overcurrent protection to engage, disabling further charging. And hence, in the case of a deeply discharged battery, this protection can become problematic. Consequently, the battery remains in its discharged state, unable to recover, as overcurrent protection effectively prevents the charging process from continuing.
Therefore, there exists a need for an onboard charger for waking up and charging a battery from a deep discharge state that overcomes one or more problems associated as set forth above.
SUMMARY
An object of the present disclosure is to provide an onboard charger for uninterrupted charging of a battery upon waking up the battery from deep discharge state.
In accordance with the first aspect of the present disclosure, there is provided an onboard charger for waking up and charging a battery from a deep discharge state, the onboard charger comprising:
- a Power Factor Correction (PFC) unit;
- a DC-DC converter; and
- a control unit,
wherein the PFC unit comprises a switching module configured to control boost operation of the PFC unit.
The present disclosure provides an onboard charger for waking up and charging a battery from a deep discharge state. The onboard charger as disclosed in the present disclosure is advantageous in terms of enabling uninterrupted charging the battery while pulling the battery out of the deep discharge state. The uninterrupted and continuous charging of the battery is achieved by minimizing the inrush current in the event of charging, while beginning of the charging process. When the charging is initiated, the difference between voltage at input side of the onboard charger and voltage at Battery terminal is high. The onboard charger of the present disclosure reduces this voltage difference by controlling the boost operation of the PFC unit. Further, the onboard charger of the present disclosure allows better utilization of battery capacity by pushing the lower voltage limit of the battery below the existing threshold voltage of the battery, for battery to enter into deep discharge mode.
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:
FIG. 1A and 1B illustrate schematic representations of an onboard charger for waking up and charging a battery from a deep discharge state, in accordance with various embodiments of the present disclosure.
FIG. 2 illustrates a flow chart of a method for waking up and charging a battery from a deep discharge state, in accordance with an embodiment 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 arrow, the non-underlined number is used to identify a general item at which the 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 charger for 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 a power source that is located outside the vehicle. This may include vehicles having power packs that are exclusively charged from a power source, as well as hybrid vehicles which may include power packs capable of being at least partially recharged via a 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 “onboard charger”, “on-board charger”, “OBC” and “charger” are used interchangeably and refer to an electrical and electronic system for converting the input alternating current (AC) power into direct current (DC) power that is suitable for charging of power pack of electric vehicle. The alternating current (AC) power is received from power source including wall sockets of residential outlets.
As used herein, the terms “Battery”, “power pack”, and “battery pack” are used interchangeably and refer to multiple individual battery cells connected to provide a higher combined voltage or capacity than what a single battery can offer. The power pack is designed to store electrical energy in form of chemical energy and supply the electrical energy as needed to various devices or systems. Power pack, as referred herein are used for various purposes such as for powering electric vehicles and other energy storage applications.
As used herein, the terms “deep discharge mode”, “deep discharge state”, “sleep mode”, “sleep state”, “dormant mode”, and “dormant state” are used interchangeably and refer to a condition where the battery’s charge level or voltage level falls to a dangerously low point, typically below a critical charge or voltage threshold. In this state, the battery is almost fully depleted, and the energy storage system cannot deliver power to the vehicle's motor or other components. To protect the battery from damage, the battery management system (BMS) may automatically shut down or enter a dormant mode.
As used herein, the terms “wake up” and “waking up” are used interchangeably and refer to the process of reactivating the battery/Battery management system (BMS) from a deep discharge state. To wake the battery up, a small current or voltage is applied to safely reactivate it. Once the battery wakes up, BMS resumes normal functioning and charging is initiated to pull the battery out of deep discharge state.
As used herein, the terms “Power factor correction”, “Power factor correction unit”, “PFC unit” and “PFC” are used interchangeably and refer to an electrical unit configured to enhance the efficiency of converting AC power to DC power for charging the vehicle's battery. This unit typically consists of a diode bridge, which first converts the AC input voltage into DC voltage. However, the DC voltage produced directly from the diode bridge often has a distorted waveform that results in a poor power factor. To correct this, the PFC unit includes LC components (inductance-capacitance filters) that smooth the current waveform and align the phase of the input current with the input voltage. The LC components help reduce harmonic distortion and ensure that the charger draws power more efficiently from the grid, with minimal reactive power. This improves the power factor, reduces energy losses, and ensures that the onboard charger operates in compliance with utility regulations, contributing to overall grid stability and efficient battery charging. Generally, active PFC is used in the form of a boost regulator and as a result the voltage appearing across the output of PFC unit is greater than the highest value of the peak voltage of the AC input voltage.
As used herein, the terms “DC-DC converter” and “DC converter” are used interchangeably and refer to a component that follows the Power Factor Correction (PFC) unit of onboard charger. After the PFC unit has corrected the power factor and converted the incoming AC voltage to a stable DC voltage, the DC-DC converter further processes this DC power to a level suitable for charging the EV's battery. The DC-DC converter adjusts the voltage and current to the precise requirements of the battery, ensuring efficient and safe charging. It typically steps down the high DC voltage (from the PFC) to a lower, regulated voltage that matches the battery’s charging profile. Additionally, the DC-DC converter manages the charging process by controlling parameters like voltage, current, and charging time to protect the battery from overcharging, overheating, or damage. This component plays a crucial role in optimizing energy transfer, improving overall charging efficiency, and extending the battery's lifespan.
As used herein, the term “control unit” refers to the component used herein, in the charger to control the operation of the PFC unit, precisely switching module of the PFC unit. The control unit is a computational element that is operable to respond to and process instructions that control 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. In PFC unit, the control unit controls the switching of switching module by comparing a sensed voltage at Battery terminal to a pre-defined voltage. When voltage at terminal voltage is below a predefined voltage the switching module is turned off, to turn-off the boost operation of PFC unit.
As used herein, the term “switching module” refers to a one of more semiconductor switches that regulate the power flow by switching on and off at high frequencies. Possible semiconductor switches may include MOSFET(s) (Metal-Oxide-Semiconductor Field-Effect Transistor(s)), IGBT(s) (Insulated-Gate Bipolar Transistor(s)), SiC MOSFET(s) (Silicon Carbide MOSFET(s)), GaN Transistor(s) (Gallium Nitride Transistor(s)), and Thyristor(s) (SCR - Silicon-Controlled Rectifier(s)) or a combination thereof. The choice of semiconductor switch depends on factors like the voltage, current, switching frequency, and efficiency requirements of the onboard charger.
As used herein, the term “input terminal” refers to a first terminal of on-board charger where the AC input voltage from an external AC power supply is applied to the charger. This terminal serves as the entry point for the electrical power that will be converted into DC power to charge the vehicle's battery. Typically, the AC input voltage is supplied from a standard electrical grid, charging station or wall sockets of any residential outlets.
As used herein, the terms “DC voltage terminal” and “DC terminal” are used interchangeably and refer to a second terminal of on-board charger at an output of rectification circuit of the PFC unit. The rectification unit converts AC input voltage to DC voltage. The rectification unit or rectifier configuration may include Single-Phase Diode Bridge Rectifier (Full-Wave Rectifier), Single-Phase Controlled Rectifier (Thyristor-Based), Active Rectifier (also known as Synchronous Rectification), Phase-Shifted Full Bridge (PSFB) Rectifier, and High-Frequency Resonant Rectifier. The choice of rectifier depends on factors such as efficiency, cost, complexity, and the specific requirements of the EV charging system.
As used herein, the terms “Power factor correction (PFC) output terminal”, “Power factor correction output terminal”, “PFC voltage terminal” and “PFC output terminal” are used interchangeably and refer to a third terminal of the onboard charger where a boosted, regulated DC voltage is provided, following the rectification. This terminal ensures that the output voltage is maintained at a stable level, while also improving the overall power factor by minimizing current distortion and reactive power.
As used herein, the terms “battery terminal” and “battery voltage terminal” are used interchangeably and refers to a fourth point of the onboard charger where the onboard charger interfaces with the battery to transfer electrical energy.
Figure 1A, in accordance with an embodiment, describes an onboard charger 100 for waking up and charging a battery 102 from a deep discharge state. The onboard charger 100 comprises a Power Factor Correction (PFC) unit 104, a DC -DC converter 106 and a control unit 108. The PFC unit 104 comprises a switching module 110 configured to control boost operation of the PFC unit 104.
Figure 1B, in accordance with an embodiment, describes an onboard charger 100 for waking up and charging a battery 102 from a deep discharge state. The onboard charger 100 comprises a Power Factor Correction (PFC) unit 104, a DC -DC converter 106 and a control unit 108. The PFC unit 104 comprises a switching module 110 configured to control boost operation of the PFC unit 104. Specifically, in this embodiment, the onboard charger 100 comprises an input voltage terminal 112, a DC voltage terminal 114, a Power factor correction PFC output terminal 116 and a Battery terminal 118.
The onboard charger 100 as disclosed in the present disclosure is advantageous in terms of enabling uninterrupted charging the battery 102 while pulling the battery 102 out of the deep discharge state. The uninterrupted and continuous charging of battery 102 is achieved by minimizing the inrush current in the event of charging, while beginning of the charging process. When the charging is initiated, the difference between voltage at input voltage terminal 112 and voltage at Battery terminal 118 is high. The onboard charger 100 reduces this voltage difference by controlling the boost operation of the PFC unit 104. Further, the onboard charger of the present disclosure allows better utilization of battery 102 capacity by pushing the lower voltage limit of the battery 102 below the existing threshold voltage of the battery 102, for battery 102 to enter into deep discharge mode.
In an embodiment, the onboard charger 100 wakes up the battery from deep discharge state upon receiving a 12V signal from an external supply, when a charging gun is connected to a charging port of the electric vehicle. Further, the 12V signal is detected at a Battery Management system of battery 102, which activates the BMS (or battery 102) and then battery 102 charging can begin.
In an embodiment, the onboard charger 100 comprises an input voltage terminal 112, a DC voltage terminal 114, a Power factor correction (PFC) output terminal 116 and a Battery terminal 118. The Input Voltage Terminal 112 is the connection point where the onboard charger receives power from an external AC source. The DC Voltage Terminal 114 provides a rectified DC output, wherein rectification is carried out by rectifier unit of the PFC unit 104. The PFC Output Terminal 116 delivers a boosted, corrected DC voltage after improving the power factor and reducing input current distortion. The Battery terminal 118 connects the charger to the battery, allowing the transfer of energy for charging.
In an embodiment, the switching module 110 is connected to the PFC unit 104 between the DC voltage terminal 114 and the PFC output terminal 116. Beneficially, the switching module 110 dynamically performs the boost operation of the PFC unit 104. While charging the battery 102, boost operation of PFC unit 104 improves the power factor, making it closer to 1 (ideal), by correcting the phase difference between voltage and current.
In an embodiment, the control unit 108 is communicably coupled to the Power factor correction (PFC) unit 104 and the Battery terminal 118. It is to be understood that the control unit 108 and the PFC unit 104 may be communicably coupled using wired communication. Alternatively, the control unit 108 and the PFC unit 104 may be communicably coupled wirelessly. Alternatively, the control unit 108, may be an integral part of PFC unit 104. Alternatively, the control unit 108 may be standalone unit within or outside the onboard charger 100. Beneficially, the control unit 108 dynamically controls the boost operation of the PFC unit 104 according to battery voltage available at the Battery terminal 118.
In an embodiment, the control unit 108 is configured to sense a voltage at the Battery terminal 118. Beneficially, control unit 108 takes reference of voltage at the Battery terminal 118 to ensure uninterrupted charging operation of the battery 102 by controlling the boost operation of the PFC unit 104, and this effectively pull the battery out of deep discharge mode.
In an embodiment, the control unit 108 is configured to operate the switching module 110, based on the sensed voltage. Beneficially, control unit 108 allows dynamic and precise control of power flow for charging of the battery 102.
In an embodiment, the control unit 108 is configured to compare the sensed voltage to a pre-defined voltage to operate the switching module 110. Beneficially, when sensed voltage is below the pre-defined value, the control unit 108 turns off the boost operation of the PFC unit 104. This reduces the voltage difference between voltage available at DC voltage terminal 114 and Battery terminal 118, which further minimizes the inrush current when the charging of battery 102 begins.
Figure 2, in accordance with an embodiment, describes a method 200 for waking up and charging a battery (such as the battery 102 of Fig. 1A) from a deep discharge state via an onboard charger (such as the onboard charger 100 of Fig. 1A). The method 200 starts at a step 202. At the step 202, the method comprises initiating charging of the battery 102 upon receiving AC voltage at an input voltage terminal (such as input voltage terminal 112 of Fig. 1B) of the onboard charger 100. At the step 204, the method comprises converting the AC voltage at the input voltage terminal 112 to a DC voltage using a Power Factor Correction PFC unit (such as the PFC unit 104 of Fig. 1A). At the step 206, the method comprises controlling a switching module (such as the switching module 110 of Fig. 1A) of the PFC unit 104 via a control unit (such as the control unit 108 of Fig. 1A) based on voltage at a Battery terminal (such as the Battery terminal 118 of Fig. 1B), to control boost operation of the PFC unit 104. At the step 208, the method comprises stepping down the voltage at Power factor correction PFC output terminal (such as a PFC output terminal 116 of Fig. 1B), to generate voltage at the Battery terminal 118. The method 200 ends at the step 208.
In an embodiment, the method 200 comprises initiating charging of the battery 102 upon receiving AC voltage at an input voltage terminal 112 of the onboard charger 100, converting the AC voltage at the input voltage terminal 112 to a DC voltage using a Power Factor Correction PFC unit 104, controlling a switching module 110 of the PFC unit 104 via a control unit 108 based on voltage at a Battery terminal 118, to control boost operation of the PFC unit 104 and stepping down the voltage at Power factor correction PFC output terminal 116 to generate voltage at the Battery terminal 118. Beneficially, the method 200 allows the uninterrupted charging of battery 102 when state of charge (SOC) and/or voltage level of the battery 102 (or voltage level of cells of the battery 102) falls below a threshold limit and the battery 102 moves into deep discharge state. Beneficially, the method 200 allows uninterrupted and continuous charging of the battery 102, by controlling the switching module 110 of the PFC unit 104 to control the boost operation of switching module 110 such that the switching module 110 cuts down the boost operation to maintain minimum difference between voltage at PFC output terminal 116 and voltage at Battery terminal 118. The minimum voltage difference between the voltage at PFC output terminal 116 and the voltage at Battery terminal 118, avoids flow of high inrush current and thus allow charging of the battery 102 causing no hazard to components of the onboard charger. Furthermore, method 200 prevents any protection circuit from engaging and stopping the charging of the battery 102 by limiting the inrush current via control of the switching module 110.
In an embodiment, the onboard charger 100 wakes up the battery from deep discharge state upon receiving a 12V signal from an external supply, when a charging gun is connected to a charging port of the electric vehicle. Further, the 12V signal is detected at a Battery Management system of battery 102, which activates the BMS (or battery 102). After BMS (or battery 102) successfully wakes up, the charging process begins.
It would be appreciated that all the explanations and embodiments of the onboard charger 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 charger (100) for waking up and charging a battery (102) upon from a deep discharge state, the onboard charger (100) comprising:
- a Power Factor Correction (PFC) unit (104);
- a DC-DC converter (106); and
- a control unit (108),
wherein the PFC unit (104) comprises a switching module (110) configured to control boost operation of the PFC unit (104).
2. The onboard charger (100) as claimed in claim 1, wherein the onboard charger (100) comprises an input voltage terminal (112), a DC voltage terminal (114), a Power factor correction (PFC) output terminal (116) and a Battery terminal (118).
3. The onboard charger (100) as claimed in claim 1, wherein the switching module (110) is connected to the PFC unit (104) between the DC voltage terminal (114) and the PFC output terminal (116).
4. The onboard charger (100) as claimed in claim 1, wherein the control unit (108) is communicably coupled to the Power factor correction (PFC) unit (104) and the Battery terminal (118).
5. The onboard charger (100) as claimed in claim 1, wherein the control unit (108) is configured to sense a voltage at the Battery terminal (118).
6. The onboard charger (100) as claimed in claim 1, wherein the control unit (108) is configured to operate the switching module (110), based on the sensed voltage.
7. The onboard charger (100) as claimed in claim 1, wherein the control unit (108) is configured to compare the sensed voltage to a pre-defined voltage to operate the switching module (110).
8. The method (200) for waking up and charging a battery (102) from a deep discharge state via an onboard charger (100), the method (200) comprising:
- initiating charging of the battery (102) upon receiving AC voltage at an input voltage terminal (112) of the onboard charger (100);
- converting the AC voltage at the input voltage terminal (112) to a DC voltage using a Power Factor Correction (PFC) unit (104);
- controlling a switching module (110) of the PFC unit (104) via a control unit (108) based on voltage at a Battery terminal (118), to control boost operation of the PFC unit (104); and
- stepping down the voltage at Power factor correction (PFC) output terminal (116) to generate voltage at the Battery terminal (118).