DESC:METHOD OF OPERATING CHARGER FOR CHARGING BATTERIES OF DIFFERENT VOLTAGE RATINGS
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202321001917 filed on 10/01/2023, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
The present disclosure generally relates to charging batteries of different voltage ratings in an electric vehicle. The present disclosure particularly relates to a method of operating a charger for charging batteries of different voltage ratings. Furthermore, the present disclosure relates to a charger for charging batteries of different voltage ratings.
BACKGROUND
Recently, there has been a rapid development in electric vehicles because of their ability to resolve pollution-related problems and serve as a clean mode of transportation. Generally, electric vehicles include a battery pack, power pack, and/or combination of electric cells for storing electricity required for the propulsion of the vehicles. The electrical power stored in the battery pack of the electric vehicle is supplied to the traction motor for moving the electric vehicle. Once the electrical power stored in the battery pack of the electric vehicle depletes, the battery pack is required to be charged from a power source by connecting the electric vehicle with a charger.
Generally, the charger of the electric vehicle delivers DC power to the battery pack of the electric vehicle. The charger of the electric vehicle typically uses an AC-power supply from the power source and converts the received AC power into DC power before supplying it to the battery. However, the conventional chargers of the electric vehicles generally have a fixed output power i.e., fixed output of current and voltage to charge the battery pack of the electric vehicle.
The different categories of electric vehicles may have battery packs and systems operating at different voltage rating levels. Such differences in the voltage rating of the battery packs require a unique charger setup for charging the battery packs of different voltage ratings.
In the existing electric vehicle chargers, for charging the batteries of different voltage ratings, the topology of the charging circuit is changed according to the change in the voltage levels. Such, changes in the topology increase the cost and complexity of the charger. Furthermore, the efficiency of the existing electric vehicle chargers is severely affected when the operating voltage level is near the extreme ends of the range of voltage. Moreover, the present control methods operating such chargers are not capable of controlling chargers in a way that the existing chargers are capable of charging battery packs of different voltage ratings.
Therefore, there exists a need for an improved control method providing variable output from a charger to charge battery packs of different voltage ratings and overcome one or more problems associated as set forth above.
SUMMARY
An object of the present disclosure is to provide a method of operating a charger for charging batteries of different voltage ratings.
Another object of the present disclosure is to provide a charger for charging batteries of different voltage ratings.
In accordance with the first aspect of the present disclosure, there is provided a method of operating a charger for charging batteries of different voltage ratings. The method comprises operating an AC-DC converter, operating a DC-DC converter, comprising a hybrid network having at least two switching legs configured in a full bridge configuration, a resonant tank, a high frequency transformer and a rectifier, and operating the full bridge configuration of the DC-DC converter in a half bridge configuration for charging batteries of different voltage ratings.
The present disclosure provides a method of operating a charger for charging batteries of different voltage ratings for an electric vehicle. Beneficially, the method eliminates the need for different chargers for charging battery packs of different voltage ratings. Advantageously, the method can be used to operate a charger for charging batteries of both 96V rating and 48V rating. Beneficially, the method eliminates the need to change the topology of the charger for charging battery packs of different voltage ratings. Advantageously, the method eliminates the need for complex architectures in charger. Beneficially, the method operates the charger in a smaller frequency band, thus, reducing stress on the components of the charger leading to better operating life of the components. Beneficially, the method causes minimal losses including switching loss in the charger during the operation. Beneficially, the method is capable of providing output power from the charger in a wide range of voltages enabling compatibility for charging a wide range of battery packs with different voltage ratings. Moreover, the method is advantageous in terms of efficiently operating the charger in constant current and constant voltage mode of charging. Beneficially, the method enables hybrid modulation in the charger during constant voltage charging mode to efficiently operate the charger near the resonant frequency of the components.
In accordance with the second aspect of the present disclosure, there is provided a charger for charging batteries of different voltage ratings. The charger comprises an AC-DC converter, a DC-DC converter comprising a hybrid network configured within the DC-DC converter, wherein the hybrid network comprises at least two switching legs configured in a full bridge configuration, a resonant tank, a high frequency transformer and a rectifier, and a microcontroller configured to control functioning of the DC-DC converter, wherein the full bridge configuration is converted to a half bridge configuration by the microcontroller for charging batteries of different voltage ratings.
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 flow chart of a method of operating a charger for charging batteries of different voltage ratings, in accordance with an aspect of the present disclosure.
Figure 2 illustrates a circuit diagram of charger for charging batteries of different voltage ratings, 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 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 charger for charging batteries of different voltage ratings and method of operation thereof 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 source” “battery pack”, “battery”, and “power 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 battery pack is designed to store electrical energy and supply it as needed to various devices or systems. Battery packs, as referred herein may be used for various purposes such as power electric vehicles and other energy storage applications. Furthermore, the battery 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 battery pack comprises a plurality of cell arrays which in turn comprises a plurality of battery cells.
As used herein, the terms “charger”, “charger for charging batteries of different voltage ratings”, “variable output off-board charger”, and “variable output charger” are used interchangeably and refer to a type of electric vehicle (EV) charger that delivers direct current (DC) power directly to the EV's battery pack. Beneficially, the variable output charger is capable of charging battery packs of different voltage ratings as the output voltage of the charger varies according to the requirement of the battery pack.
As used herein, the term “AC-DC converter” refers to a device that converts alternating current (AC) to direct current (DC). The AC-DC converter converts the high-voltage AC power from the grid to the DC power required for charging the battery pack of the electric vehicle. Preferably, the AC-DC converter is a switching converter that uses a semiconductor switch to convert the AC to DC. Beneficially, the AC-DC converter is more efficient than conventional linear converters.
As used herein, the term “DC-DC converter” refers to a device that converts direct current (DC) from one voltage level to another. The DC-DC converter is responsible for converting the high-voltage DC power from the AC-DC converter to the lower voltage DC power that is required by the battery pack of the electric vehicle. Preferably, the DC-DC converter is a switching converter that offers the best combination of efficiency, cost, and performance.
As used herein, the term “hybrid network” refers to a charging system that uses a combination of two or more different types of chargers to provide fast charging capabilities.
As used herein, the terms “switching legs”, “inverter legs”, and “phase legs” are used interchangeably and refer to individual circuit blocks of the charger which are responsible for converting the DC power from the DC link capacitor into high frequency AC power for the high frequency transformer. It is to be understood that the switching legs are designed based on the configuration of the converter. It is to be understood that the switching legs comprise a pair of switches.
As used herein, the term “high frequency transformer” refers to a transformer that operates at a higher frequency than a traditional transformer and efficiently converts high frequency AC power from the switching circuit to DC power for the battery pack of the electric vehicle connected as load. Beneficially, the high frequency transformer is small in size and lightweight compared to a traditional transformer.
As used herein, the terms “rectification bridge”, and “rectifier” are used interchangeably and refer to an electrical device that converts alternating current (AC) to direct current (DC).
As used herein, the terms ‘microcontroller’ and ‘processor’ are used interchangeably and refer to a computational element that is operable to respond to and process instructions that control the system. Optionally, the microprocessor may be 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. Furthermore, the term “microprocessor” may refer to one or more individual processors, processing devices, and various elements associated with a processing device that may be shared by other processing devices. Furthermore, the microprocessor may be designed to handle real-time tasks with high performance and low power consumption. Furthermore, the microprocessor may comprise custom and/or proprietary processors.
As used herein, the term “power source” refers to an AC power supply received from the grid. The power source may be a commercial AC power supply or a domestic AC power supply.
As used herein, the terms “DC link capacitor”, “DC bus capacitor”, and “capacitor” are used interchangeably and refer to a capacitor that is used to smooth out the fluctuating DC voltage coming from a converter. The DC link capacitor functions to smooth out the power between the two components, stabilize the DC bus voltage, and act as energy storage for transient loads.
As used herein, the term “gate drivers” refers to electronic components responsible for controlling the switching of switches including Metal Oxide Semiconductor Field Effect Transistors (MOSFET), Insulated Gate Bipolar Transistors (IGBT) that may be used as switches in the charger. 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 “switches” and “plurality of switch” are used interchangeably and refers to power electronics devices that control the flow of electrical current. The switches are responsible for converting the DC voltage from the DC link capacitor into an AC waveform for high frequency transformer. The switches may be at least one of MOSFETs, IGBTs, transistors, or a combination thereof.
As used herein, the term “resonant tank” refers to a circuit consisting of an inductor and a capacitor that are connected to each other. The resonant tank is used to create a resonant frequency at which the current and voltage in the circuit are synchronized.
As used herein, the term “electromagnetic interference filters” refers to specialized components designed to reduce or mitigate the electromagnetic noise generated by the charger’s power electronics during operation. It is to be understood that electromagnetic interference filters or EMI filters may comprise conducted electromagnetic interference filters, radiated electromagnetic interference filters, or a combination thereof.
As used herein, the term “cooling system” refers to a combination of heat sink and cooling chambers used for cooling down the power electronics components and microcontroller of the charger. The cooling system may comprise a cooling fan, vapor cooling chamber, liquid cooling chamber, or a combination thereof.
As used herein, the term ‘communicably coupled’ refers to a bi-directional connection between the various components of the system. The bi-directional connection between the various components of the system enables the exchange of data between two or more components of the system. Similarly, the bi-directional connection between the system and other elements/modules enables the exchange of data between the system and the other elements/modules.
As used herein, the term “sensors” refers to a component in the system and/or arrangement to measure, monitor, or detect specific parameters, conditions, and/or events. The sensors may comprise current sensors, voltage sensors, hall effect sensors, insulation monitoring sensors, or a combination thereof.
Figure 1, in accordance with an embodiment, describes a method 100 of operating a charger 200 for charging batteries of different voltage ratings. The method 100 starts at step 102 and finishes at step 106. At step 102, the method 100 comprises operating an AC-DC converter 202. At step 104, the method 100 comprises operating a DC-DC converter 204, comprising a hybrid network 206 having at least two switching legs 208a, 208b configured in a full bridge configuration, a resonant tank 222, a high frequency transformer 210 and a rectifier 212. At step 106, the method 100 comprises operating the full bridge configuration of the DC-DC converter 204 in a half bridge configuration for charging batteries of different voltage ratings.
The present disclosure provides a method 100 of operating a charger 200 for charging batteries of different voltage ratings for an electric vehicle. Beneficially, the method 100 eliminates the need for different chargers for charging battery packs of different voltage ratings. Advantageously, the method 100 can be used to operate a charger 200 for charging batteries of both 96V rating and 48V rating. Beneficially, the method 100 eliminates the need to change the topology of the charger 200 for charging battery packs of different voltage ratings. Advantageously, the method 100 eliminates the need for complex architectures in charger 200. Beneficially, the method 100 operates the charger 200 in a smaller frequency band, thus, reducing stress on the components of the charger 200 leading to better operating life of the components. Beneficially, the method 100 cause minimal losses including switching loss in the charger 200 during the operation. Beneficially, the method 100 is capable of providing output power from the charger 200 in a wide range of voltages enabling compatibility for charging a wide range of battery packs with different voltage ratings. Moreover, the method 100 is advantageous in terms of efficiently operating the charger 200 in constant current and constant voltage mode of charging. Beneficially, the method 100 enables hybrid modulation in the charger 200 during constant voltage charging mode to efficiently operate the charger 200 near the resonant frequency of the components.
In an embodiment, the method 100 comprises converting AC input received from a power source 216 into DC voltage for the DC-DC converter 204, using a rectification bridge of the AC-DC converter 202. Beneficially, the AC input received from the power source 216 is converted into a stable DC voltage for the DC-DC converter 204.
In an embodiment, the method 100 comprises correcting power factor of the AC input received from the power source 216, using an inductor 202b of the AC-DC converter 202. Beneficially, the inductor 202b improves the power factor of the AC input received from the power source 216 to reduce losses in the AC-DC converter 202.
In an embodiment, the method 100 comprises minimizing voltage ripple between the AC-DC converter 202 and the DC-DC converter 204, using a first DC link capacitor 218a installed between the AC-DC converter 202 and the DC-DC converter 204. Beneficially, the first DC link capacitor 218a absorbs the periodic voltage and/or current spikes between the AC-DC converter 202 and the DC-DC converter 204. It would be appreciated that the first DC link capacitor 218a would absorb the excess amount of voltage and/or current between the AC-DC converter 202 and the DC-DC converter 204, and would supply the same to the DC-DC converter 204 when there is a drop in voltage and/or current between the AC-DC converter 202 and the DC-DC converter 204.
In an embodiment, the method 100 comprises controlling switching sequence of a pair of switches S1, S2 of each of the switching leg 208a, 208b. It is to be understood that the switching sequence plays an important role in the efficient functioning of the DC-DC converter 204. Beneficially, the switching sequence is accurately controlled for the efficient functioning of the DC-DC converter 204.
In an embodiment, the method 100 comprises controlling a plurality of gate drivers to controlling switching sequence of a pair of switches S1, S2 of each of the switching leg 208a, 208b. Beneficially, the gate drivers provide high-voltage and high-current signals needed to control the switching of switches.
In an embodiment, in the full bridge configuration, the pair of switches S1, S2 of one switching leg 208a switch alternatively with respect to switching of the pair of switches S1, S2 of another switching leg 208b. Beneficially, the full bridge configuration completely converts the input DC voltage into high frequency AC voltage.
In an embodiment, the method 100 comprises converting the DC voltage received from the AC-DC converter 202 into a high frequency AC input for the high frequency transformer 210, in the full bridge configuration. Beneficially, the high frequency transformer 210 functions on the high frequency AC input.
In an embodiment, in the half bridge configuration, one switching leg 208a acts as a high frequency switching leg and another switching leg 208b acts as a low frequency switching leg. Beneficially, such configuration of the switching legs 208a, 208b converts the full bridge configuration into a half bridge configuration.
In an embodiment, the method 100 comprises keeping one switch of the pair of switches S1, S2 of the low frequency switching leg 208b permanently on while the pair of switches S1, S2 of the high frequency switching leg 208a are switching alternatively with respect to each other, in the half bridge configuration. Beneficially, such operation of the switches S1, S2 of the switching legs 208a, 208b output half of the voltage received at the input of the DC-DC converter 204. It is to be understood that the high frequency switching in the high frequency switching leg 208a is controlled based on the design of the switches S1, S2 and the output requirements. In an example, the high frequency switching ranges between few KHz to few 100 KHz. Whereas, the low frequency switching in the low frequency switching leg 208b is controlled based on the thermal capacity of the switches S1, S2.
In an embodiment, the method 100 comprises reducing the DC voltage received from the AC-DC converter 202 while being converted into the high frequency AC input for the high frequency transformer 210, in the half bridge configuration. Beneficially, such reduction of voltage increases the operational voltage range of the charger 200.
In an embodiment, the method 100 comprises stepping up or stepping down the received high frequency AC input to provide a variable AC output, using the high frequency transformer 210. Beneficially, the high frequency transformer 210 further varies the output as per the requirement after the variation of output due to full bridge or half bridge configuration of the switching legs 208a, 208b.
In an embodiment, the method 100 comprises rectifying the variable AC output of the high frequency transformer 210 into the variable DC output, using the rectifier 212. Beneficially, the variable DC output received from the rectifier 212 is supplied to load 220 (battery pack of the electric vehicle being charged).
In an embodiment, the method 100 comprises minimizing voltage ripple between the rectifier 212 and a load 220, using a second DC link capacitor 218b installed between the rectifier 212 and the load 220. Beneficially, the second DC link capacitor 218b absorbs the periodic voltage and/or current spikes between the rectifier 212 and the load 220. It would be appreciated that the second DC link capacitor 218b would absorb the excess amount of voltage and/or current between the rectifier 212 and the load 220, and would supply the same to the load 220 when there is a drop in voltage and/or current between the rectifier 212 and the load 220.
In an embodiment, the method 100 comprises sensing voltage rating of the load 220, using a voltage rating sensor. Beneficially, the sensed voltage rating of the load 120 is used to decide the configuration of the switching legs 108a, 108b.
In an embodiment, the method 100 comprises sensing current being received by the load 220, using a current sensor. Beneficially, the sensed current information of the load 220 is used to decide the functioning of the high frequency transformer 210 as step-up transformer or step-down transformer.
In an embodiment, the method 100 comprises controlling the switching sequence of the pair of switches S1, S2 of each of the switching leg 208a, 208b between the full bridge configuration and the half bridge configuration, based on the sensed voltage rating of the load 220. Beneficially, the components of the charger 200 are operated near the resonant frequency for maximum efficiency of operation and reduction of switching losses. The variation in the output voltage is achieved by the converting the full bridge configuration into half bridge configuration.
In an embodiment, the method 100 comprises keeping at least one inductor 222a and at least one capacitor 222b of the resonant tank 222 in resonance. Beneficially, the charger 200 acts a resonant converter due to resonant tank. More beneficially, the at least one inductor 222a and at least one capacitor 222b are kept in resonance to maximize the operational efficiency of the charger 200.
In an embodiment, the method 100 comprises controlling a switching frequency of the pair of switches S1, S2 of each of the switching leg 208a, 208b in both the full bridge configuration and the half bridge configuration to provide the variable DC output. Beneficially, the switching frequency of the pair of switches S1, S2 of each of the switching leg 208a, 208b is controlled to operate the charger 200 near to the resonant frequency for achieving maximum efficiency.
In an embodiment, the method 100 comprises detecting a power requirement of the batteries charging by the charger 200, by sensing the voltage and the current being received by the load 220. It is to be understood that the battery may require low power in a constant voltage charging mode. It is to be understood that during the constant voltage charging mode, the requirement of voltage and power to charge the battery is low compared to battery in a constant current charging mode.
In an embodiment, the method 100 comprises operating the DC-DC converter 204 in the full bridge configuration or the half bridge configuration based on the power requirement of the batteries charging at the charger 200. Beneficially, the DC-DC converter 204 is operated in the half bridge configuration during low power requirement such as the constant voltage charging mode to operate the charger 200 near the resonant frequency. Beneficially, this hybrid modulation of the charger 200 according to the power requirement of the battery maximizes the operation efficiency of the charger and reduces stress on the components of the charger 200 by operating the charger near the resonant frequency.
It is to be understood that the battery connected to the charger 200 (either the 96V rating or the 48V rating) may be of lower current rating compared to other batteries. In such condition, the DC-DC converter 204 would operate in the half bridge configuration as the power requirement of the batteries charging at the charger 200 is low. Furthermore, it is to be understood that a 96V rating battery may require low amount of current as the total power transfer rating of the battery is low. In such condition, the DC-DC converter 204 would operate in the half bridge configuration as the power requirement of the batteries charging at the charger 200 is low. Beneficially, this method of hybrid modulation of the charger 200 is beneficial for maximum operational efficiency of the charger 200.
Figure 2, in accordance with an embodiment, describes a circuit diagram of the variable output charger 200 for electric vehicle, comprising an AC-DC converter 202, a DC-DC converter 204, and a microcontroller 214. The DC-DC converter 204 comprises a hybrid network 206 configured within the DC-DC converter 204, wherein the hybrid network 206 comprises at least two switching legs 208a, 208b configured in a full bridge configuration, a high frequency transformer 210 and a rectifier 212. The microcontroller 214 is configured to control functioning of the DC-DC converter 204. The full bridge configuration is converted to a half bridge configuration by the microcontroller 214 to provide variable DC output by the DC-DC converter 204. Furthermore, the AC-DC converter 202 comprises a rectification bridge 202a configured to convert AC input received from a power source 216 into DC voltage for the DC-DC converter 204. Furthermore, the AC-DC converter 202 comprises an inductor 202b for power factor correction of the AC input received from the power source 216. Furthermore, the variable output charger 200 comprises a first DC link capacitor 218a installed between the AC-DC converter 202 and the DC-DC converter 204 to minimize voltage ripple between the AC-DC converter 202 and the DC-DC converter 204. Furthermore, each of the switching leg 208a, 208b comprises a pair of switches S1, S2, wherein the microcontroller 214 is configured to control switching sequence of the pair of switches S1, S2 of each of the switching leg 208a, 208b. Furthermore, in the full bridge configuration, the pair of switches S1, S2 of one switching leg 208a switch alternatively with respect to switching of the pair of switches S1, S2 of another switching leg 208b. Furthermore, in the full bridge configuration, the DC voltage received from the AC-DC converter 202 is converted into a high frequency AC input for the high frequency transformer 210. Furthermore, one switching leg 208a acts as a high frequency switching leg and another switching leg 208b acts as a low frequency switching leg. Furthermore, in the half bridge configuration, one switch of the pair of switches S1, S2 of the low frequency switching leg 208b is kept permanently on while the pair of switches S1, S2 of the high frequency switching leg 208a are switching alternatively with respect to each other. Furthermore, in the half bridge configuration, the DC voltage received from the AC-DC converter 202 is halved while being converted into the high frequency AC input for the high frequency transformer 210. Furthermore, the high frequency transformer 210 steps up or steps down the received high frequency AC input to provide a variable AC output. Furthermore, the rectifier 212 of the DC-DC converter 204 is configured to rectify the variable AC output of the high frequency transformer 210 into the variable DC output. Furthermore, the variable output charger 200 comprises a second DC link capacitor 218b installed between the rectifier 212 and a load 220 to minimize voltage ripple between the rectifier 212 and the load 220. Furthermore, the variable output charger 200 comprises a voltage rating sensor, wherein the voltage rating sensor provides voltage rating of the load 220 to the microcontroller 214. Furthermore, the variable output charger 200 comprises a current sensor, wherein the current sensor information of current being received by the load 220 to the microcontroller 214. Furthermore, the microcontroller 214 controls the switching sequence of the pair of switches S1, S2 of each of the switching leg 208a, 208b between the full bridge configuration and the half bridge configuration, based on the sensed voltage rating of the load 220. Furthermore, the DC-DC converter 204 comprises a resonant tank 222, wherein at least one inductor 222a and at least one capacitor 222b of the resonant tank 222 are in resonance. Furthermore, the microcontroller 214 controls a switching frequency of the pair of switches S1, S2 of each of the switching leg 208a, 208b in both the full bridge configuration and the half bridge configuration to provide the variable DC output. Furthermore, the DC-DC converter 204 acts as a resonant DC-DC converter due to the resonant tank 222 and provides the variable DC output to the load 220.
In an embodiment, the DC-DC converter 204 comprises more than two switching legs based on the design of the DC-DC converter 204. It is to be understood that the person skilled in the art may choose the number of switching legs based on the design choice and output requirements.
In an embodiment, the charger 200 comprises a plurality of electromagnetic interference filters configured to filter noise emission from the DC-DC converter 204. In a specific embodiment, the plurality of electromagnetic interference filters comprises a combination of conducted electromagnetic interference filters and radiated electromagnetic interference filters. Beneficially, the conducted electromagnetic interference filters suppress electromagnetic interference filters that are conducted through electrical conductors. Similarly, the radiated electromagnetic interference filters suppress electromagnetic interference filters that are radiated as radio waves.
In an embodiment, the charger 200 comprises power management integrated circuits configured to supply power to the microcontroller 214 and the voltage and current sensors. Beneficially, the power management integrated circuits are configured to maintain a calibrated supply of power to the critical components including microcontroller 214 and the voltage and current sensors. It is to be understood that the power management integrated circuits would receive input power from an auxiliary power supply.
In an embodiment, the charger 200 comprises a cooling system configured to maintain an optimum temperature of the DC-DC converter 204 and the microcontroller 214. Beneficially, the cooling system ensures optimal functioning of the electronic components by maintaining the optimum temperature of the DC-DC converter 204 and the microcontroller 214.
In an exemplary embodiment, when an electric vehicle with battery pack voltage rating of 96V is connected to the charger 200, the microcontroller 214 would sense the same via the voltage rating sensor and configure the two switching legs 208a, 208b in the full bridge configuration. However, when an electric vehicle with battery pack voltage rating of 48V is connected to the charger 200, the microcontroller 214 would sense the same via the voltage rating sensor and configure the two switching legs 208a, 208b in the half bridge configuration.
In an embodiment, the microcontroller 214 controls a switching frequency of the pair of switches S1, S2 of each of the switching leg 208a, 208b in both the full bridge configuration and the half bridge configuration to provide the variable DC output.
It is to be understood that all the explanations and embodiments pursuant to method 100 also applies mutatis mutandis to the charger 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
,CLAIMS:WE CLAIM:
1. A method (100) of operating a charger (200) for charging batteries of different voltage ratings, wherein the method (100) comprises:
- operating an AC-DC converter (202);
- operating a DC-DC converter (204), comprising a hybrid network (206) having at least two switching legs (208a, 208b) configured in a full bridge configuration, a resonant tank (222), a high frequency transformer (210) and a rectifier (212); and
- operating the full bridge configuration of the DC-DC converter (204) in a half bridge configuration for charging batteries of different voltage ratings.
2. The method (100) as claimed in claim 1, wherein the method (100) comprises converting AC input received from a power source (216) into DC voltage for the DC-DC converter (204), using a rectification bridge of the AC-DC converter (202).
3. The method (100) as claimed in claim 1, wherein the method (100) comprises correcting power factor of the AC input received from the power source (216), using an inductor (202b) of the AC-DC converter (202).
4. The method (100) as claimed in claim 1, wherein the method (100) comprises minimizing voltage ripple between the AC-DC converter (202) and the DC-DC converter (204), using a first DC link capacitor (218a) installed between the AC-DC converter (202) and the DC-DC converter (204).
5. The method (100) as claimed in claim 1, wherein the method (100) comprises controlling switching sequence of a pair of switches (S1, S2) of each of the switching leg (208a, 208b).
6. The method (100) as claimed in claim 1, wherein in the full bridge configuration, the pair of switches (S1, S2) of one switching leg (208a) switch alternatively with respect to switching of the pair of switches (S1, S2) of another switching leg (208b).
7. The method (100) as claimed in claim 1, wherein the method (100) comprises converting the DC voltage received from the AC-DC converter (202) into a high frequency AC input for the high frequency transformer (210), in the full bridge configuration.
8. The method (100) as claimed in claim 1, wherein in the half bridge configuration, one switching leg (208a) acts as a high frequency switching leg and another switching leg (208b) acts as a low frequency switching leg.
9. The method (100) as claimed in claim 1, wherein the method (100) comprises keeping one switch of the pair of switches (S1, S2) of the low frequency switching leg (208b) permanently on while the pair of switches (S1, S2) of the high frequency switching leg (208a) are switching alternatively with respect to each other, in the half bridge configuration.
10. The method (100) as claimed in claim 1, wherein the method (100) comprises reducing the DC voltage received from the AC-DC converter (202) while being converted into the high frequency AC input for the high frequency transformer (210), in the half bridge configuration.
11. The method (100) as claimed in claim 1, wherein the method (100) comprises stepping up or stepping down the received high frequency AC input to provide a variable AC output, using the high frequency transformer (210).
12. The method (100) as claimed in claim 1, wherein the method (100) comprises rectifying the variable AC output of the high frequency transformer (210) into the variable DC output, using the rectifier (212).
13. The method (100) as claimed in claim 1, wherein the method (100) comprises minimizing voltage ripple between the rectifier (212) and a load (220), using a second DC link capacitor (218b) installed between the rectifier (212) and the load (220).
14. The method (100) as claimed in claim 1, wherein the method (100) comprises sensing voltage rating of the load (220), using a voltage rating sensor.
15. The method (100) as claimed in claim 1, wherein the method (100) comprises sensing current being received by the load (220), using a current sensor.
16. The method (100) as claimed in claim 1, wherein the method (100) comprises controlling the switching sequence of the pair of switches (S1, S2) of each of the switching leg (208a, 208b) between the full bridge configuration and the half bridge configuration, based on the sensed voltage rating of the load (220).
17. The method (100) as claimed in claim 1, wherein the method (100) comprises keeping at least one inductor (222a) and at least one capacitor (222b) of the resonant tank (222) in resonance.
18. The method (100) as claimed in claim 1, wherein the method (100) comprises controlling a switching frequency of the pair of switches (S1, S2) of each of the switching leg (208a, 208b) in both the full bridge configuration and the half bridge configuration to provide the variable DC output.
19. The method (100) as claimed in claim 1, wherein the method (100) comprises detecting a power requirement of the batteries charging by the charger (200), by sensing the voltage and the current being received by the load (220).
20. The method (100) as claimed in claim 1, wherein the method (100) comprises operating the DC-DC converter (204) in the full bridge configuration or the half bridge configuration based on the power requirement of the batteries charging at the charger (200).
21. A charger (200) for charging batteries of different voltage ratings, wherein the charger (200) comprises:
- an AC-DC converter (202);
- a DC-DC converter (204) comprising a hybrid network (206) configured within the DC-DC converter (204), wherein the hybrid network (206) comprises at least two switching legs (208a, 208b) configured in a full bridge configuration, a resonant tank (222), a high frequency transformer (210) and a rectifier (212); and
- a microcontroller (214) configured to control functioning of the DC-DC converter (204),
wherein the full bridge configuration is converted to a half bridge configuration by the microcontroller (214) for charging batteries of different voltage ratings.