GB2640659A

GB2640659A - System for generating a control voltage

Info

Publication number: GB2640659A
Application number: GB2406030.3A
Authority: GB
Inventors: Choudhary Manoj; Hassan Ali
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2024-04-30
Filing date: 2024-04-30
Publication date: 2025-11-05
Also published as: GB202406030D0; WO2025228603A1

Abstract

a system 250 for generating a control voltage for controlling the connection of an electrical power supply to a vehicle power system 200 comprises a first electrical connector 251 which is connectable to the vehicle power system 200 via a first switch 241, and a second electrical connector 252 which is connectable to the vehicle power system 200 via a second switch 242; and a logic circuit 253 comprising a solid-state device, wherein the logic circuit 253 has a first input, a second input, and an output 256, the first input is connected to the first electrical connector 251 and the second input is connected to the second electrical connector 252, the logic circuit 253 is configured to output a first predefined voltage level when a direct current power supply is applied across the first and second electrical connectors 251, 252, and output a second predefined voltage level when an alternating current power supply is applied across the first and second electrical connectors 251, 252, wherein the output of the logic circuit comprises the control voltage.

Description

SYSTEM FOR GENERATING A CONTROL VOLTAGE

TECHNICAL FIELD

The present disclosure relates to a system for generating a control voltage. Aspects of the invention relate to a system for generating a control voltage for controlling the connection of an electrical power supply to a vehicle power system, a system for controlling the connection of a vehicle battery pack to an electrical power supply, and a vehicle comprising such a system.

BACKGROUND

Battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs) comprise traction motors and traction batteries for supplying electrical energy to the traction motors. Some traction batteries can be recharged with electrical energy from a power supply external to the vehicle, such as electrical energy from an electrical grid. Such external power supplies are typically referred to as Electric Vehicle (EV) chargers or charging stations. EV chargers are generally classified into different levels (Levels 1, 2 and 3), with higher levels being associated with higher power outputs and faster charging. Level 1 and 2 chargers provide alternating current (AC) to an on-board converter (OBC) of a vehicle, which converts the AC to direct current (DC) which, in turn, is used to charge the traction battery. In contrast, Level 3 chargers typically provide a DC power supply directly to the traction battery of a vehicle.

A number of different standards exist for EV charging plugs and EV charging sockets/connectors. Some standards are used in specific geographical regions and some are specific to particular vehicle models. Standards such as CCS (Combined Charging System) allow for charging by AC or DC power supplies. EV charging plugs made to the CCS1 and CCS2 standards have dedicated pins for supplying each of AC and DC, respectively, for charging a vehicle traction battery. Accordingly, a vehicle which is provided with an EV connector in accordance with one of the CCS1 or CCS2 standards will have a socket with respective receiving portions for each of the respective AC and DC pins of the plug. In contrast, charging plugs made in accordance with standards such as the North American Charging Standard (NACS), use the same pins to supply either AC or DC to a vehicle. For compatibility with NAGS, it is therefore necessary for the electrical power system of an electric vehicle to be configured such that, when AC is provided by the NACS plug, the current is applied to the OBC, whereas when DC is provided by the NACS plug, the current is applied directly to the traction battery of the vehicle to provide more rapid charging.

It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a system for generating a control voltage for controlling the connection of an electrical power supply to a vehicle power system, a system for controlling the connection of a vehicle battery pack to an electrical power supply, and a vehicle comprising such a system as claimed in the appended claims.

According to an aspect of the present invention there is provided a system for generating a control voltage for controlling the connection of an electrical power supply to a vehicle power system, the system comprising: a first electrical connector which is connectable to the vehicle power system via a first switch, and a second electrical connector which is connectable to the vehicle power system via a second switch; and a logic circuit comprising a solid-state device, wherein the logic circuit has a first input, a second input, and an output, wherein the first input is connected to the first electrical connector and the second input is connected to the second electrical connector, wherein the logic circuit is configured to output a first predefined voltage level when a direct current power supply is applied across the first and second electrical connectors, wherein the output of the logic circuit comprises the control voltage. The logic circuit may also be configured to output a second predefined voltage level when an alternating current power supply is applied across the first and second electrical connectors.

Embodiments of the present invention advantageously provide a control signal which can be used to control the connection of an external power supply to the vehicle power system of a vehicle by means of a logic circuit alone. This means that no additional software-based processing is required in order to distinguish between the type of power supply, i.e. AC or DC supply. With such an arrangement, the type of power supply can be determined as soon as the external supply is connected to the vehicle, i.e. at the instant that the EV charging plug of the charging apparatus is connected to the corresponding socket on the vehicle, because the control voltage is generated in response to the external power supply being connected across the first and second electrical connectors. In turn, this allows for more rapid control of components of the vehicle power system, such as the first and second switches, to configure it to receive either an AC power supply or a DC power supply as appropriate.

The first predefined voltage level may be zero volts. The second predefined voltage level may be greater than zero volts. The aforementioned predefined control voltages can advantageously be used to control opening and closing of the first and/or second switches of a vehicle power system.

The solid-state device may comprise an operational amplifier having an inverting input, a non-inverting input and an output, wherein the first input of the logic circuit is connected to the inverting input of the operational amplifier, the second input of the logic circuit is connected to the non-inverting input of the operational amplifier, and the output of the operational amplifier is connected to the output of the logic circuit. With this configuration, the output of the operational amplifier may conveniently provide an output of zero volts when a DC power supply is connected across the first and second electrical connectors and provide a non-zero voltage output when an AC power supply is connected across the first and second electrical connectors.

The output of the operational amplifier may be connected to the output of the logic circuit via a rectifier. The rectifier may comprise a diode, a capacitor and a resistor, wherein the capacitor and the resistor are connected in parallel to form a filter, and wherein an input of the diode is connected to the output of the operational amplifier and an output of the diode is connected to the capacitor such that the output of the logic circuit comprises the filtered voltage output from the rectifier. Wth this arrangement, when the control voltage output from the logic circuit is non-zero, it is conveniently maintained at a substantially constant level which may facilitate the use of the control voltage to more reliably open and/or close the first and/or second switch.

The system may comprise an inverter arranged to receive the output from the logic circuit and configured such that a voltage output from the inverter is non-zero when the output of the logic circuit is zero, and a voltage output from the inverter is zero when the output of the logic circuit is non-zero. By inverting the control voltage output from the logic circuit, an output of zero volts is conveniently provided when an AC power supply is connected across the first and second electrical connectors and a non-zero voltage is provided when a DC power supply is connected across the first and second electrical connectors. This is particularly convenient in the case that the first and/or second switches are required to be closed when a DC power supply is connected and open when an AC power supply is connected. With this arrangement the first and second switches can conveniently be configured to default to an open state when the control signal is zero volts and will only be closed when the control voltage is non-zero. Accordingly, the switches are only closed in the event of a positive determination that a DC power supply is connected across the first and second electrical connectors.

Accordingly, a risk that an AC power supply is connected directly to positive and negative terminals of a vehicle battery, which is undesirable, is mitigated.

According to another aspect of the present invention there is provided a system for controlling the connection of a vehicle battery pack to an electrical power supply, the system comprising: the system for generating a control voltage as described above in accordance with the preceding aspect; a battery pack having a positive terminal and a negative terminal, wherein the positive terminal is connectable to the first electrical connector via the first switch, and the negative terminal is connectable to the second electrical connector via the second switch; and a switch controller configured to open and/or close the first and/or second switch in dependence on the control voltage.

The battery pack may comprise a plurality of batteries which are connectable in parallel or in series.

According to a further aspect of the invention, there is provided a vehicle comprising the system of any one of the preceding aspects.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination.

That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a charging plug according to the North American Charging Standard; Figure 2 shows a vehicle in accordance with an embodiment of the present invention; Figure 3 is a schematic view of a vehicle power system of the vehicle of Figure 2 in combination with a system for generating a control voltage for controlling the connection of an electrical power supply to the vehicle power system in accordance with an embodiment of the present invention; Figure 4 is a schematic of the system for generating a control voltage of Figure 3; Figure 5A is a simplified schematic of the system of Figure 4 when connected to an electrical power supply which supplies DC power; Figure 5B is a plot of an output voltage of the system of Figure 5A with respect to time; Figure 6A is a simplified schematic of the system of Figure 4 when connected to an electrical power supply which supplies AC power; and Figure 6B is a plot of an output voltage of the system of Figure 6A with respect to time.

DETAILED DESCRIPTION

Referring to Figure 1, an EV charging plug 10 in accordance with the North American Charging Standard (NAGS) has a five-pins layout comprising first and second primary pins 11, 12, a ground pin 13, a Control Pilot (CP) pin 14 and a Proximity Pilot (PP) pin 15. In accordance with NAGS, the first pin 11 provides either the positive side of a DC voltage supply or a one line (L1) of an AC voltage supply. The second pin 12 provides either the negative side of a DC voltage supply or, in the case of an AC supply, the second phase (L2) or neutral of a split or single-phase connection.

Referring to Figures 2 and 3, a vehicle 100 has power system 200 which generally comprises a traction battery or battery pack 210, a load bus 220, an on-board converter (OBC) 230, and switching means 240. In the present embodiment, the vehicle 100 is a battery electric vehicle (BEV), but in other embodiments, the vehicle may be a hybrid electric vehicle (HEV).

In the present embodiment, the traction battery 210 comprises first and second batteries 211, 212 which may be connected in series or in parallel. The traction battery 210 is capable of being charged by either a 400V or 800V supply. Having the capability to accept, for example, substantially 800V (e.g. a voltage between 450V to 850V) or substantially 400V (e.g. a voltage between 250V to 450V) at the same input allows for a flexible system capable of operating with different voltage requirements. The traction battery 210 provides a high voltage, i.e. substantially 800V, supply to the load bus 220.

The load bus 220 comprises circuitry which connects the traction battery 210 to one or more inverters of the vehicle 100 which, in tum, control one or more electric motors for providing motive power to the vehicle 100 during driving. In the present embodiment, the load bus 220 comprises high voltage and ground connections 221 to an inverter mounted in the front of the vehicle and respective high voltage and ground connections 222 to an inverter mounted in the rear of the vehicle. The load bus 220 additionally comprises a bi-directional DCDC converter 223 for converting the high voltage supply from the traction battery 210 to a nominal 12V supply for powering auxiliary vehicle systems and for providing power to a nominal 12V battery 224.

The vehicle 100 is provided with an electrical charging socket 225 for receiving an electrical charging plug of an external electrical power supply. In Figure 3, the socket 225 is shown schematically and comprises respective first, second and third inlet portions 226, 227, 228. In the present embodiment, the first and second inlet portions 226, 227 are configured to receive respectively the first and second pins 11, 12 of the EV charging plug 10 shown in Figure 1. The third inlet portion 228 is configured to receive the pins of an EV charging plug configured to provide an AC power supply in accordance with a level 1 or level 2 EV charger. The third inlet portion 228 of the charging socket 225 is connected directly to the OBC 230. The OBC 230 is an AC to DC converter. Accordingly, when the vehicle power system 200 is connected to an external AC power supply via the third inlet portion 228, the OBC 230 is operable to convert the AC to DC for charging the traction battery 210.

The switching means 240 comprises first and second switches 241, 242 and a plurality of further switches 243. The first and second inlet portions 226, 227 are coupled to the first and second switches 241, 242, respectively. The first and second switches 241, 242 are each so-called 'fast charging' switches, which are operable to selectively connect respective ones of the first and second inlet portions 226, 227 to respective positive and negative terminals of the traction battery 210. As described previously, EV charging plugs made in accordance with certain standards, such as the NACS, are capable of delivering either a DC or an AC power supply. Accordingly, when the first and second inlet portions 226, 227 receive a DC power supply, the first and second switches 241, 242 can be closed so as to connect the DC power supply to the traction battery 210 for fast charging thereof Alternatively, in the case that the first and second inlet portions 226, 227 receive an AC power supply the first and second switches 241, 242 can be opened so as to prevent direct connection of an AC power supply to the traction battery 210. In this instance, the plurality of further switches 243 can be utilised so as to connect the first and second inlet portions 226, 227 to the OBC 230 so that when AC is supplied to the first and second inlet portions 226, 227 it is converted to DC by the OBC 230 for charging the traction battery 210.

The vehicle 100 further comprises a system 250 for generating a control voltage for controlling the connection of an electrical power supply to the vehicle power system 200. The system for generating a control voltage 250 comprises first and second electrical connectors 251, 252, a logic circuit 253 and an inverter 270. As shown in Figure 3, the first electrical connector 251 is disposed between the first inlet portion 226 of the socket 225 and the first switch 241 of the switching means 240. Likewise, the second electrical connector 252 is disposed between the second inlet portion 227 of the socket 225 and the second switch 242 of the switching means 240.

Referring to Figure 4, the logic circuit 253 comprises a first input 261, a second input 262, a solid-state device 255 and an output 256. The first input 261 of the logic circuit 253 is provided by the voltage at the first electrical connector 251. The second input 262 of the logic circuit 253 is provided by the voltage at the second electrical connector 252.

As shown in Figure 4, the logic circuit 253 also comprises a plurality of resistors 260. The plurality of resistors 260 serve to step-down the voltage at the first electrical connector 251, e.g. 800V, to an operational voltage of the solid-state device 255, e.g. 5V. The logic circuit 253 further comprises a rectifier 265. The rectifier 265 comprises a diode 266, a capacitor 267 and a resistor 268. The capacitor 267 and the resistor 268 a connected together in parallel so as to form a filter to which the output 266b from the diode 266 is provided. Accordingly, the control voltage which is output from the logic circuit 253 is the 'filtered' output from the diode 266 of the rectifier 265.

In the presently described embodiment, the solid-state device 255 comprises an operational amplifier, e.g. an LTC7652 type operational amplifier. The operational amplifier 255 has an inverting input 257, a non-inverting input 258 and an output 259. The inverting input 257 of the operational amplifier 255 is connected to the first input 261 of the logic circuit 253. The non-inverting input 258 of the operational amplifier 255 is connected to the second input 262 of the logic circuit 253. The output 259 of the operational amplifier 255 is connected to the output 256 of the logic circuit 253.

Figure 4 illustrates how either an AC or a DC power supply may be connected to the first and second electrical connectors 251, 252. The operation of the logic circuit 253 will now be described in more detail with reference to Figures 5A and 5B, which show the logic circuit 253 with a DC power supply connected across the respective first and second inputs 261, 262 thereof and the associated input/output voltage plots, and Figures 6A and 6B, which show the logic circuit 253 with an AC power supply connected across the respective first and second inputs 261. 262 thereof and the associated input/output voltage plots. It should be noted that, in each of Figures 5 A and 6A, certain elements of the logic circuit 253 shown in Figure 4, e.g. the plurality of the resistors 260, have been omitted for clarity.

Referring to Figures 5A and 5B, when a DC power supply is connected across the first and second electrical connectors 251, 252, a positive voltage is provided to the inverting input 257 of the operational amplifier 255 from the first input 261 of the logic circuit 253 and a nominal zero voltage (e.g. ground voltage) is provided to the non-inverting input 258 of the operational amplifier 255 from the second input 262 of the logic circuit 253. Accordingly, the voltage at the inverting input 257 is always higher than the voltage at the non-inverting input 258 when a DC power supply is connected across the first and second electrical connectors 251, 252. In Figure 5B, the voltage at the inverting input 257 and the output voltage 256 of the logic circuit 253 are plotted with respect to time. As shown, in this situation, the output 259 of the operational amplifier 255 is low, i.e. a nominal zero voltage. Accordingly, the output 256 of the logic circuit 253 is also low, i.e. OV.

Referring to Figures 6A and 6B, when an AC power supply is connected across the first and second electrical connectors 251, 252, the voltage at the inverting input 257 oscillates as shown by the corresponding line on Figure 6B. When the voltage at the inverting input 257 is lower than the voltage at the non-inverting input 258, i.e. ground voltage, the output 259 of the operational amplifier 255 is high, i.e. a positive voltage. In the presently described embodiment, the output 259 of the operational amplifier 255 is coupled to an input 266a of the diode 266 of the rectifier 265. The output 266b of the diode 266 is connected to one side of the capacitor 267. As described previously, the capacitor 267 and the resistor 268 are connected together in parallel so as to form a filter. Accordingly, with this arrangement, the output 256 of the logic circuit 253 comprises the filtered voltage output from the rectifier 265. As shown in Figure 6B, the voltage at the output 256 of the logic circuit 253 when the AC power supply is connected is approximately 4V, i.e. the output 256 of the logic circuit 253 is high.

The output 256 of the logic circuit 253 can therefore be used to determine whether an AC or a DC power supply is connected across the first and second electrical connectors 251, 252. More specifically, the logic circuit 253 is configured such that, when a DC power supply is connected across the first and second electrical connectors 251, 252, the output 256 of the logic circuit 253 is a first predefined voltage, e.g. zero volts, and when an AC power supply is connected across the first and second electrical connectors 251, 252, the output 256 of the logic circuit 253 is a second predefined voltage, which is greater than zero volts, e.g. an average voltage of approximately 4V in the case of the presently described embodiment. The output 256 of the logic circuit 253 therefore provides a control voltage which may be used to control connection of an external power supply to the vehicle power system 200 of the vehicle 100 as will now be described in more detail.

Referring again to Figure 3, the output 256 of the logic circuit 253 is provided to a switch controller 280. The switch controller 280 comprises circuitry which is arranged to receive the output 256 from the logic circuit 253 and to cause each one of the first and second switches 241, 242 of the switching means 240 to open or close in dependence on the control voltage. When the first and second switches 241, 242 are closed, the first and second electrical connectors 251, 252 are respectively connected to the positive and negative terminals of the traction battery 210. Accordingly, the switch controller 280 is configured such that, when the output 256 of the logic circuit 253 is indicative of a DC power supply being connected across the first and second electrical connectors 251, 252, the first and switches are closed. Conversely, when the output 256 of the logic circuit 253 is indicative of an AC power supply being connected across the first and second electrical connectors 251, 252, the first and second switches 241, 242 are opened so as to prevent an AC power supply from being applied directly to the terminals of the traction battery 210. In this situation, the switch controller 280 is configured to control the plurality of further switches 243 to electrically connect the first and second electrical connectors 251, 252 to respective inputs of the OBC 230 which converts the AC power supply to DC power.

In the presently described embodiment, the system for generating a control voltage 250 comprises an inverter 270 which receives the output 256 from the logic circuit 253. The inverter 270 is configured such that a voltage output from the inverter 270 is non-zero when the output 256 of the logic circuit 253 is zero. Conversely, a voltage output from the inverter 270 is zero when the output 256 of the logic circuit 253 is non-zero. Accordingly, when a DC power supply is connected across the first and second electrical connectors 251, 252 such that the output 256 of the logic circuit 253 is low, e.g. zero volts, the presence of the inverter 270 means that a positive, non-zero voltage is output to the switch controller 280. Conversely, when an AC power supply is connected across the first and second electrical connectors 251, 252 such that the output 256 of the logic circuit 253 is non-zero, e.g. 4V, the presence of the inverter 270 means that a zero voltage is output to the switch controller 280. The aforementioned arrangement may be convenient because the first and switches 241, 242 default to the open state in the event that the control voltage output to the switch controller 280 is zero. Put another way, closing of the first and second switches 241, 242 necessitates that a positive, nonzero voltage is output to the switch controller 280 in order for the first and second switches 241, 242 to be closed. This arrangement advantageously mitigates the possibility that an AC power supply will erroneously be connected directly to the terminals of the traction battery 210.

In an alternative embodiment, the first and second electrical connectors 251, 252 may be connected to the respective positive and negative terminals of the traction battery 210 when the respective first and second switches 241, 242 are open and disconnected from the terminals when they are closed. With this arrangement, the inverter 270 may be omitted.

It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

CLAIMS1. A system for generating a control voltage for controlling the connection of an electrical power supply to a vehicle power system, the system comprising: a first electrical connector which is connectable to the vehicle power system via a first switch, and a second electrical connector which is connectable to the vehicle power system via a second switch; and a logic circuit comprising a solid-state device, wherein the logic circuit has a first input, a second input, and an output, wherein the first input is connected to the first electrical connector and the second input is connected to the second electrical connector, wherein the logic circuit is configured to output a first predefined voltage level when a direct current power supply is applied across the first and second electrical connectors, and output a second predefined voltage level when an alternating current power supply is applied across the first and second electrical connectors, wherein the output of the logic circuit comprises the control voltage.
2. A system as claimed in claim 1, wherein the first predefined voltage level is zero volts and the second predefined voltage level is greater than zero volts.
3. A system as claimed in claim 2, wherein the solid-state device comprises an operational amplifier having an inverting input, a non-inverting input and an output, wherein the first input of the logic circuit is connected to the inverting input of the operational amplifier, the second input of the logic circuit is connected to the non-inverting input of the operational amplifier, and the output of the operational amplifier is connected to the output of the logic circuit.
4. A system as claimed in claim 3 wherein the output of the operational amplifier is connected to the output of the logic circuit via a rectifier.
5. A system as claimed in claim 4, wherein the rectifier comprises a diode, a capacitor and a resistor, wherein the capacitor and the resistor are connected in parallel to form a filter, and wherein an input of the diode is connected to the output of the operational amplifier and an output of the diode is connected to the capacitor such that the output of the logic circuit comprises the filtered voltage output from the rectifier.
6. A system as claimed in claim 4 or claim 5, wherein the system comprises an inverter arranged to receive the output from the logic circuit and configured such that a voltage output from the inverter is non-zero when the output of the logic circuit is zero, and a voltage output from the inverter is zero when the output of the logic circuit is non-zero.
7. A system for controlling the connection of a vehicle battery pack to an electrical power supply, the system comprising: the system for generating a control voltage as claimed in any preceding claim; a battery pack having a positive terminal and a negative terminal, wherein the positive terminal is connectable to the first electrical connector via the first switch, and the negative terminal is connectable to the second electrical connector via the second switch; and a switch controller configured to open and/or close the first and/or second switch in dependence on the control voltage.
8. A system as claimed in claim 7, wherein the battery pack comprises a plurality of batteries which are connectable in parallel or in series.
9. A vehicle comprising the system of any one of claims 1 to 8.