Method and device for determining insulation state of electric vehicle for safe operation

Abstract

The invention provides a method and device for measuring electrical parameters of an electric vehicle to determine insulation parameters. The method comprises the steps that data communication with the electric vehicle is established, the vehicle is switched to an electric energy exchange mode, and the electric energy exchange mode is a battery charging mode or an electric energy output mode; measuring an electric vehicle battery terminal voltage relative to the electric vehicle electrical chassis through the electric energy exchange port; and processing the battery terminal voltage, which is a voltage measured relative to the electrical chassis of the electric vehicle, to determine the isolation resistance and / or insulation state of the electric vehicle.

Description

Technical Field

[0001] This disclosure relates to methods and apparatus for obtaining electrical insulation parameters of live parts of a vehicle with a high-voltage electrical system, and more specifically, to methods and apparatus for determining the electrical insulation of an electric vehicle to ensure operational safety. Background Technology

[0002] Electric vehicles have become one of the main types of vehicles on roads worldwide.

[0003] Among the different types of electric vehicles, pure electric vehicles (EVs or BeVs) are likely to have one of the highest growth rates. A BeV is an electric vehicle equipped with onboard energy storage to provide electrical power to run its main unit (which may include a single drive motor or multiple drive motors).

[0004] BeV needs to be charged (or recharged) from time to time so that the stored energy can be replenished with new energy after it is consumed by the operation of the drive motor and / or other accessories (such as heaters or air conditioners).

[0005] In order for BeV to achieve a reasonable driving range (for example, a range comparable to that of traditional gasoline vehicles), the on-board energy storage of BeV needs to have a storage capacity of at least 30kWh, while storage capacities of 50kWh, 80kWh, 100kWh, 120kWh and even higher are not uncommon.

[0006] Batteries are currently the most practical choice for BeV vehicle-mounted energy storage devices, and battery cells are usually connected in parallel and series to form battery assemblies to meet the requirements for operating voltage and energy storage capacity.

[0007] Ordinary BeV battery modules have a rated voltage of 300V and above, and the current trend is to use a higher rated voltage of 800V and above in order to deliver more power to the drive motor at a lower current, since the heat dissipation I²R depends on the square of the operating current.

[0008] For example, the 2024 Model Y® vehicle's battery pack has a rated voltage of 357V, a rated battery capacity of 78.1kWh, and a 400V electrical system architecture.

[0009] However, vehicles operating under high voltages of 300V, 500V and above means that a compatible high-voltage electrical system is required, and electrical insulation inevitably becomes a major safety factor of common concern to users, passengers and regulatory authorities.

[0010] As the voltage of high-voltage electrical systems in electric vehicles continues to increase to 1000V DC and above, adequate insulation of live components in these systems is a crucial safety factor for ensuring operational safety. Insulation defects in these components can lead to arcing and / or electric shock. Arcing faults in electric vehicles can damage related cables and equipment and potentially cause the entire vehicle to burn out within a short period.

[0011] The high-voltage circuits of electric vehicles, especially those constituting the drive system (such as the high-voltage live components in the circuit connecting the battery pack and the drive motor), are part of a closed system. For operational safety considerations or requirements, this closed system is mostly sealed, sometimes even using multiple seals. This means that high-voltage live components cannot be directly contacted. Therefore, assessing and / or determining the insulation state of electrical circuits, while not entirely impossible, presents significant challenges.

[0012] As is well known, the insulation performance of electrical systems, such as the high-voltage electrical systems of electric vehicles (especially their high-voltage drive systems), deteriorates over time due to factors such as prolonged exposure to heat generated during operation and environmental aging. Therefore, to improve operational and user safety, it is crucial to periodically assess and / or determine the insulation status of electric vehicles (especially their high-voltage live components). The United Nations document E / ECE / 324 / Rev.2 / Add.99 / Rev.3-E / ECE / TRANS / 505 / Rev.2 / Add.99 / Rev.3 (hereinafter referred to as the “UN Document”), published on 23 March 2022, provides practical guidance for the measurement of isolation resistance in electric vehicles. This document and its contained definitions are incorporated herein by reference.

[0013] However, it is well known that the high-voltage live components of electric vehicles are highly sealed, protected, and enclosed systems, virtually inaccessible from the outside of the electric vehicle unless this enclosed system is disassembled or partially disassembled to remove the sealing, protection, and / or protective structures. Clearly, disassembly or partial disassembly followed by reassembly would have adverse side effects and is undesirable for both safety and / or durability.

[0014] There is an urgent need for methods and / or tools that can help determine the insulation parameters of electric vehicles without disassembling them or their battery components, in order to improve the operational safety of pure electric vehicles. Summary of the Invention

[0015] The electric vehicles (such as pure electric vehicles) described in this article are equipped with an on-board rechargeable energy storage system (REESS). This system is an energy storage device configured as such as a battery pack to provide the electric vehicle with operating power, including driving power.

[0016] The electric vehicle is configured to perform power exchange operations and includes a power exchange port configured to assist in these operations. The power exchange operation can be performed as a power input operation or optionally as a power output operation. The electric vehicle can operate in either a power input mode or a power output mode. When the electric vehicle is in power input mode, it is in power input operation, and electrical energy flows into the electric vehicle from an external energy source through the power exchange mode. When the electric vehicle is in power output mode, it is in power output operation, and electrical energy flows from the electric vehicle to an external load through the power exchange mode.

[0017] When the electric vehicle is in power input mode (which can be battery charging mode to replenish the REESS energy storage), the power exchange port is configured as a battery charging port (hereinafter referred to as the "charging port"). This port is used to assist external or off-vehicle power sources in charging the on-board battery pack. In this operating mode, the charging port is configured as a power interface to assist in the electrical connection between the pure electric vehicle's electrical system and an external power source. In charging mode, electrical energy is delivered to the on-board REESS through the power exchange port.

[0018] When the electric vehicle is in power output mode, the energy stored in the REESS is delivered to the external load through the power exchange port, which is then used as a power output port (“charging port”). In this operating mode, the power output port is configured as a power interface to assist in the electrical connection between the pure electric vehicle’s electrical system and the external load.

[0019] Power exchange ports (such as charging ports) are typically mounted on the vehicle body and located directly beneath a cover, which is an external port cover that can be opened to access the power exchange port. The port cover is usually an integral part of the external vehicle structure and is configured for easy access to the charging port.

[0020] The power exchange port (including its shape and layout) can be configured to conform to current power exchange operation standards to facilitate power exchange operations. During power exchange operations, the power exchange port will be in power exchange coupling with a compatible power coupling interface (which may be referred to as a power coupling head). The power coupling head may be referred to as a charging head or charging gun.

[0021] During energy exchange operations, including battery charging, the charging head is mechanically and electrically connected to the electric vehicle through the energy exchange port. The charging head (also known as a charging gun, or simply "gun") is typically of an industry standard type.

[0022] Currently, there are several major standards for charging guns used in pure electric vehicles, such as China's GB / T 20234 standard, the International Electrotechnical Commission's IEC 61851 and IEC 62196 standards, the United States' SAE J1772 standard, Tesla's NACs standard, and Japan's CHAdeMo standard. Each standard charging gun has a specific shape and pin / terminal layout.

[0023] In addition, there are several major standard communication protocols for charging pure electric vehicles, such as OCPP, ISO15118, IEC61851, CHAdeMo, and CCS. Charging standards are usually associated with standard charging protocols to enable computer-based intelligent charging.

[0024] Each pure electric vehicle is equipped with an onboard computer to assist in intelligent vehicle control, including operation control and charging control. The onboard computer may include multiple controllers, including a main controller and multiple peripheral controllers. Each controller is an onboard controller, which may be a computer-based controller, a logic array-based controller, etc., without loss of generality.

[0025] Because the charging port needs to be easily exposed and accessible for convenient battery charging, and it is also a component of the high-voltage circuit system of a pure electric vehicle, pure electric vehicles are usually configured such that the high-voltage circuit system and the charging port are electrically isolated (i.e. mutually insulated) unless the pure electric vehicle is in a battery charging state.

[0026] To prepare a pure electric vehicle for power exchange (such as battery charging), operators typically need to open port covers (such as the charging port cover), for example by selecting an option on the vehicle's control panel or using a maintenance controller. With the port cover in the open position, the power exchange ports (such as the charging port) remain electrically isolated from the high-voltage electrical system until the pre-check procedure is successfully completed.

[0027] To ensure that pure electric vehicles are ready for power exchange (such as battery charging), the vehicle controller of the pure electric vehicle will check whether a proper coupling is formed between the charging gun and the pure electric vehicle (or more specifically, between the charging gun and the power exchange port (such as the charging port)).

[0028] When the power exchange port (such as the charging port) of the pure electric vehicle is properly coupled with the charging gun, and after the protocol exchange between the charging station and the pure electric vehicle or between the pure electric vehicle and the external load is successfully completed, and the pure electric vehicle is ready to perform power exchange (such as charging), the pure electric vehicle will operate the internal switch to connect the live parts of the high-voltage system to the power exchange port (such as the charging port or the power output port) after the aforementioned pre-charging conditions are met.

[0029] A typical pure electric vehicle is equipped with an onboard control system configured to control the operation of the entire vehicle, including battery management (such as battery charging and power output) and drive motor operation. The onboard control system (usually called the onboard computer, or simply "computer") needs to be an intelligent or smart control system because the operation and safety requirements of pure electric vehicles are extremely complex. Pre-charge condition checks and disconnect switch operations are typically performed by the onboard computer (also known as the onboard controller).

[0030] This document discloses methods and apparatus for safely, non-destructively, or non-invasively measuring the insulation parameters of live components in high-voltage electrical systems of electric vehicles (also referred to herein as pure electric vehicles). In this document, "live component" refers to a conductive component intended to carry electrical energy under normal operating conditions; "high voltage" refers to an electrical component or circuit classified as high voltage according to United Nations documents if its operating voltage is DC 60 volts or higher and 1500 volts or lower, or AC root mean square (rms) 30 volts or higher and 1000 volts or lower.

[0031] The vehicle (electric or pure electric vehicle) includes: a REESS (such as a battery pack), an electric host for providing driving power to drive the electric vehicle; a power exchange port; a switchable DC bus system configured to provide a power exchange path between the battery pack and the power exchange port when the vehicle is in power exchange mode; a controller configured to perform protocolized data communication through the power exchange port; and a vehicle chassis, which is an electrical chassis. The battery pack has a high-voltage positive terminal and a high-voltage negative terminal. The high-voltage positive terminal is connected to the high-voltage positive conductor of the DC bus system, and the high-voltage negative terminal is connected to the high-voltage negative conductor of the DC bus system. The DC bus system is a high-voltage bus system, including high-voltage live components (referred to as "live components").

[0032] Methods for measuring electrical parameters of electric vehicles to determine insulation parameters include: - Connect electronic circuitry to the power exchange port, including an isolation resistance measurement circuitry; - Establish data communication with the electric vehicle to switch the electric vehicle to power exchange mode, and connect the isolation resistance measurement circuit between the electric vehicle's live parts and the electrical chassis; - When the electric vehicle is operating in power exchange mode, voltage measurement and / or recording of voltage measurement data are performed, wherein the voltage is the voltage between the energized components and the electrical chassis; - Process the voltage measurement data to obtain insulation parameters for determining the electrical insulation status of the electric vehicle.

[0033] The method may include: disconnecting the isolation resistance measurement circuit from the electric vehicle after performing voltage and / or recording the voltage measurement data.

[0034] The power exchange mode can be either power input mode or power output mode.

[0035] The power input mode is also known as the battery charging mode.

[0036] When the electric vehicle is operating in battery charging mode, the power exchange port can be used as a battery charging port; when the electric vehicle is operating in power output mode, the power exchange port can be used as a power output port. The power output port and the power input port can be the same physical port or separate physical ports.

[0037] The electrified components of an electric vehicle include a DC high-voltage bus system (hereinafter referred to as the "DC bus system"), which has a DC high-voltage positive side (hereinafter referred to as the "positive side") and a DC high-voltage negative side (hereinafter referred to as the "negative side").

[0038] The positive side includes the DC high voltage positive conductor (or simply "positive conductor") and the positive terminal of the battery assembly.

[0039] The negative side includes the DC high voltage negative conductor (or simply "negative conductor") and the negative terminal of the battery assembly.

[0040] When not in power exchange mode, the power exchange port and the DC high-voltage bus system can be isolated (i.e., electrically isolated), and when in power exchange mode, the power exchange port and the DC high-voltage bus system can be connected (i.e., electrically connected).

[0041] When the power exchange port is connected to the DC high-voltage bus system, the two are interconnected through a low-impedance bus system, which includes a low-impedance positive path and a low-impedance positive path.

[0042] The isolation resistance measurement circuit may be included in the insulation monitoring device (IMD), such as the GYID-10 series DC IMD, the specifications of which are incorporated herein by reference.

[0043] The electrified components of an electric vehicle may include an AC high-voltage bus system that connects a power exchange port to an AC-DC converter, wherein the AC-DC converter is configured as an interface between the AC high-voltage bus system (hereinafter referred to as the "AC bus system") and the DC high-voltage bus system.

[0044] An alternating current bus system has a live wire side and a neutral wire side. The live wire side may include one or three live wire conductors, and the neutral wire side includes one neutral wire conductor.

[0045] The AC bus system and the DC bus system are electrically isolated by an AC-DC converter.

[0046] The isolation resistance of an AC bus system can be measured using an IMD (such as the GYID-10 series AC IMD).

[0047] From another perspective, this method can be described as including: - Establish data communication with the electric vehicle to switch the vehicle to a power exchange mode, which is either a battery charging mode or a power output mode. - Measure the battery terminal voltage of the electric vehicle relative to the electric vehicle's electrical chassis via the power exchange port; - Process the battery terminal voltage (i.e., the voltage measured relative to the electric vehicle's electrical chassis) to determine the electric vehicle's isolation resistance and / or insulation status.

[0048] Apparatus suitable for implementing the method may include electronic circuitry for connecting to the power exchange port of an electric vehicle.

[0049] The electronic circuit may include a controller circuit and a measurement circuit.

[0050] The measurement circuit may include an isolation resistance measurement circuit, which includes a voltage sensor. The controller circuit may be configured to: perform protocol-based data communication with the electric vehicle to switch the electric vehicle to a power exchange mode and connect the isolation resistance measurement circuit between the energized components of the electric vehicle and the electric vehicle's electrical chassis; when the electric vehicle is operating in power exchange mode, perform voltage measurement and / or record voltage measurement data, the voltage being the voltage between the energized components and the electrical chassis; and process the voltage measurement data to determine the isolation resistance and / or electrical insulation status of the electric vehicle.

[0051] The isolation resistance measurement circuit may include one or more resistors of known resistance values ​​for switchable connection between the live parts of the electric vehicle and the electric vehicle's electrical chassis.

[0052] The device may include an electrical circuit for assisting in the exchange of electrical energy between the electric vehicle and the device via an electrical exchange port.

[0053] The device may include an electrical coupling port for coupling with the electrical exchange port of an electric vehicle.

[0054] The power coupling port can be configured as a charging port or a charging gun.

[0055] In this specification, “electrical energy exchange” and “electrical energy communication” are used interchangeably; unless the context requires otherwise, “insulation”, “energy” and “electrical energy” refer to electrical insulation, electrical energy and electrical power, respectively. Attached Figure Description

[0056] The invention will be described in conjunction with the accompanying drawings, wherein: Figure 1 is a block diagram of the example device described in the present invention; Figure 2 is a schematic diagram of the operating status of the example device; Figures 3A to 3C are flowcharts of the example process flow described in the disclosure of this invention; Figures 3D to 3E are flowcharts of AC and DC arc fault monitoring as described in the present invention. Detailed Implementation

[0057] The methods disclosed herein can be implemented using an apparatus. Example apparatus suitable for implementing the methods disclosed herein may include: - Data communication circuit or data exchange, configured to enter data communication with electric vehicle (hereinafter referred to as "EV"), and to switch the electric vehicle to power communication mode through data exchange with the electric vehicle; - Electronic circuitry configured to acquire and optionally process key material electrical parameters of the electric vehicle when the electric vehicle is in a power communication operation state, for use in determining insulation parameters.

[0058] When an electric vehicle switches to power communication mode (also known as power exchange mode), it will be ready to enable power communication between the onboard power storage device and the external power circuit.

[0059] External electrical circuits are used as tools to assist in obtaining, acquiring, or collecting key electrical parameters of electric vehicles for insulation parameter determination, because the internal electrical circuits of electric vehicles are highly sealed, protected, and / or isolated and difficult to access.

[0060] The onboard energy storage device (also known as a rechargeable energy storage system, or "REESS") of an electric vehicle is used to provide electrical energy to power the electric vehicle's drive system.

[0061] When an electric vehicle is in power communication mode, electrical energy will flow between the vehicle's on-board power storage device and the power circuit through the vehicle's power exchange port.

[0062] The power exchange port can be a port commonly referred to as a charging port, but its function is no longer limited to charging electric vehicles. It has been extended to outputting electrical energy to external loads, such as in so-called "V2V" (vehicle-to-vehicle) or "V2X" (vehicle-to-everything) operations.

[0063] Electrical communication can be in either mode 1 or mode 2.

[0064] In the first mode, electrical energy from an external power source is supplied to the electric vehicle's REESS, and the REESS's stored energy increases accordingly. In this power communication mode, the electric vehicle's REESS is charging, and the electric vehicle is in either "charging" mode or "battery charging" mode.

[0065] In the second mode, the REESS supplies power to the external load, and the REESS's stored power decreases accordingly. In this power communication mode, the electric vehicle's REESS is discharging, and the electric vehicle is in either "power output" or "power export" mode.

[0066] Currently, most REESS (Rechargeable Energy Storage System) in electric vehicles are in the form of multi-kilowatt battery packs. In this specification, unless the context requires otherwise, "battery pack" and "REESS" are used interchangeably and have the same meaning.

[0067] Therefore, electrical communication between an electric vehicle and an external electrical circuit can be achieved in the following ways: i) direct electrical communication between the electric vehicle's on-board energy storage device and the external electrical circuit; ii) electrical communication between the electric vehicle's on-board energy storage device and the device through the electric vehicle's on-board energy converter.

[0068] When the electric vehicle is in direct electrical communication with an external electrical circuit, the REESS is interconnected with the charging port of the electric vehicle through a low-impedance electrical path, the resistance of which is negligible or minimal.

[0069] When an electric vehicle communicates with an external power circuit via an on-board power converter, this communication is referred to as indirect power communication. The on-board power converter is connected to the power exchange port and the REESS via a pair of low-impedance power paths. The pair of low-impedance power paths includes one low-impedance power path with negligible or minimal resistance that interconnects the power exchange port with the on-board power converter, and another low-impedance power path with negligible or minimal resistance that interconnects the on-board power converter with the REESS.

[0070] The device may include its own power circuitry to assist in power communication and parameter acquisition. Although this power circuitry is located outside the electric vehicle, it is part of the device's internal structure. In this specification, unless the context requires otherwise, "power circuitry" refers to the power circuitry located outside the electric vehicle.

[0071] An electrical circuit may include a first power port, a second power port, and at least one power path interconnecting the first power port and the second power port. The power path may be a DC power path, including a high-voltage DC positive conductor and a high-voltage DC negative conductor. The power path may also be an AC power path, including a set of live conductors and a neutral conductor. According to current standards, for a three-phase AC system, the set of live conductors includes three live conductors, and for a single-phase AC system, the set of live conductors includes one live conductor.

[0072] An electrical circuit may include multiple power paths that interconnect power input ports and power output ports.

[0073] Each of the multiple power paths is a candidate power path, and each path can be selectively operated. Only one path can be selected as the operating power path at any given time.

[0074] Multiple power paths may include a first power path and a second power path, with the second power path being an alternative to the first power path.

[0075] The first path can be a DC power path, configured for DC power output at the power output port, and the second path can be an AC power path, configured for AC power output at the power output port.

[0076] The power circuit can be configured such that the power path or multiple power paths are housed within a sealed and insulated enclosure, so that only the input and output ports are accessible to the user to ensure safety.

[0077] The device can be configured such that a first power port is a power input port and a second power port is a power output port, configured to couple power and data to an electric vehicle. When the device is in this first configuration (which is an electric vehicle charger configuration), the electric vehicle (or more specifically, the REESS of the electric vehicle) is in a power input mode (also known as a power import mode, charging mode, or battery charging mode).

[0078] The device can be configured such that a first power port is a power output port for outputting power to an external load, and a second power port is a power input port for coupling power and data to the electric vehicle. In this second configuration, the electric vehicle (or more specifically, the REESS of the electric vehicle) is in power output mode (also known as power export mode).

[0079] Electric vehicle charger configuration

[0080] When the device is in electric vehicle charger configuration (or simply charger configuration), the power input port is configured as a power input interface for coupling with a power source, which is the energy source that supplies power to the electric vehicle; and the power output port is configured as a power output interface for coupling with the electric vehicle, so that power can flow from the device to the electric vehicle.

[0081] The electrical circuit may include one or more charging heads connected to an electrical output port. Each of the charging heads may be configured as a charging gun, having a specific shape and layout specifications that meet the requirements of a specific type of electric vehicle or electric vehicle charging standard.

[0082] The charging gun is configured to perform protocol-based data communication and power communication with the electric vehicle. Protocol-based data communication refers to data communication with the electric vehicle according to common standards used for data communication. Once the protocol-based data communication is successfully completed, the electric vehicle will enter charging mode, and a charging connection will be established between the device and the electric vehicle, wherein the charging gun and charging port operate as either a power communication interface or a charging interface.

[0083] The power supply can be AC ​​power (such as mains power) or DC power.

[0084] The power source can be an internal power source for the device, or an external power source relative to the device.

[0085] DC power paths may include power converters.

[0086] When the power source is AC, the power converter can be an AC-DC power converter, enabling the device to supply DC output power.

[0087] The AC / DC power converter can be a general-purpose AC / DC power converter with a variable DC output voltage that can be selected electronically.

[0088] The AC / DC power converter can be configured for three-phase or single-phase power input.

[0089] When the power supply is a DC power supply, the power converter can be a DC / DC power converter, enabling the device to supply DC power with an output voltage that is the same as or different from the DC input voltage of the power supply.

[0090] The power converter can be a power converter assembly, including AC / DC power converters and DC / DC power converters, and each power converter can be operated with a variable output voltage selectable by electronic control.

[0091] Power converters, whether AC / DC power converters and / or DC / DC power converters, have an input side and an output side, and the input side and the output side are preferably electrically isolated.

[0092] The power circuit can be switchable, allowing one power path to be selected from multiple power paths through electronic control.

[0093] Electronic circuits may include sensing circuits, control circuits, data communication infrastructure, and optional monitoring circuits, peripheral circuits and / or other circuits.

[0094] The sensing circuit may include sensing components or sensing sub-components for sensing, measuring and / or acquiring electrical parameters to determine critical electrical insulation parameters of the electric vehicle.

[0095] The control circuit is configured to control the overall operation of the device, including sending electronic control signals to operate the switch (thereby selecting an electrical energy path as the operating electrical energy path), communicating data with the electric vehicle, acquiring data from the electrical energy path, and performing other control functions.

[0096] When the device establishes a charging connection with an electric vehicle, electrical energy used to charge the electric vehicle's battery pack will flow from the power source to the electric vehicle through the device.

[0097] The power output port interface is also configured as a data communication interface, enabling the device and the electric vehicle to exchange data through protocol-based data communication, thereby establishing a charging connection between the device and the electric vehicle.

[0098] The power output port interface may include a charging gun configured to establish a charging connection between the device and the electric vehicle.

[0099] The device may include multiple charging guns connected to the power output port interface for optional use.

[0100] Multiple charging guns may include different types of charging guns that meet different electric vehicle requirements or different electric vehicle standards, for selection and use.

[0101] Multiple charging guns can have different pin, socket, and / or shape configurations to be compatible with different charging port configurations of different electric vehicles.

[0102] The control circuit may include a controller, a data storage device (including volatile and non-volatile storage devices), switches (including electronic switches, electromechanical switches, mechanical switches, arc fault circuit interrupters, etc.), and data and control buses.

[0103] The control circuit can be configured to select one of the switchable power paths as the charging path to supply charging power to electric vehicles in the charging connection state.

[0104] The control circuit can be configured to establish a charging connection with the electric vehicle through a protocol-based data communication via a power output port interface or a charging gun.

[0105] The data storage device can pre-store executable instructions, enabling the controller to execute these stored instructions and enter into protocol-based data communication with the electric vehicle.

[0106] Electric vehicles can be configured to have either an AC charging mode or a DC charging mode.

[0107] When an electric vehicle is in DC charging mode, a low-impedance current path will be established between the battery pack terminals and the power output port interface to assist battery charging.

[0108] When an electric vehicle is in AC charging mode, a low-impedance current path will be established between the on-board AC / DC converter and the power output port interface to assist battery charging, and the battery assembly terminals of the electric vehicle will be shielded behind the on-board power converter.

[0109] The controller can operate the switch by executing stored instructions, thereby enabling the selection of the power path.

[0110] The controller may include a microprocessor or a cluster of multiple microprocessors.

[0111] The monitoring circuit may include multiple sensors, such as voltage sensors, current sensors, insulation monitoring devices (IMD), arc fault detectors, etc.

[0112] The sensor can be configured to acquire voltage and current parameters of each conductor or part of a conductor in an electrical circuit.

[0113] For example, voltage and current sensors can be set up to detect the voltage and current of the DC positive and DC negative conductors (both of which are high-voltage DC conductors).

[0114] For example, voltage and current sensors can be set up to detect the voltage and current of each AC live conductor and AC neutral conductor.

[0115] Data storage devices may include random access memory (RAM), read-only memory (ROM), solid-state drives (SSDs), etc.

[0116] The data storage device can pre-store multiple data communication protocols to facilitate protocol-based data communication between the device and electric vehicles of different types, models, and / or brands.

[0117] The device can be configured to allow the user to input the brand, type and / or model of the electric vehicle, and the controller will select a set of data communication protocols for protocolized data communication to establish a charging connection between the device and the electric vehicle.

[0118] Control and monitoring circuits are components of the device's electronic circuitry, and the device's electronic circuitry may also include additional peripheral circuitry, such as telecommunications circuitry (e.g., wireless telecommunications front-ends for applications such as WiFi, Bluetooth, and Ethernet).

[0119] The device may include a user interface to assist human-machine interaction (HMI). Electric vehicle information (such as brand, type, and / or model) can be input into the device through the HMI.

[0120] The power input port, power output port, and switchable power path are components of the device's power circuit.

[0121] Human-computer interaction interfaces may include, for example, displays (such as touch display panels) for data input and information display.

[0122] The device may include a connection port to facilitate connection to an external user interface and / or an external computer.

[0123] The device may include a chassis connector for establishing an electrical connection with the chassis of an electric vehicle, thereby establishing a common reference ground between the device and the electric vehicle.

[0124] The device may include a housing (which may be a metal housing) to make it a standalone device or a module of a modular system.

[0125] The device may have a first reference ground and a second reference ground that are electrically isolated from each other, and each reference ground is electrically grounded.

[0126] The first reference ground can be connected to the AC power ground, and the second reference ground can be the circuit ground of the electronic circuit, used to connect to the electrical ground of the electric vehicle (represented by the vehicle chassis).

[0127] To ensure operational safety, the metal casing of the device may be selected as the first reference ground, which is grounded or connected to the grounding terminal of an external power supply.

[0128] Since the first reference ground and the second reference ground are electrically isolated from each other, there is no common electrical ground between the power input port and the electronic circuit.

[0129] The device may have a tower-like overall form, making its height greater than its base width or base length.

[0130] The device has a circuit ground, which is a floating ground (FG) and is electrically isolated from the device ground or from the ground of an external power source.

[0131] The chassis connector connects to and forms part of the floating ground, and when a common ground is established between the electric vehicle and the device's floating ground, the electric vehicle chassis is electrically isolated from the grounding of the external power source.

[0132] The device can be configured as a mobile device, with the bottom of the device supported by wheels.

[0133] Example device

[0134] Referring to FIG1, the example device 10 disclosed herein includes an electrical circuit and an electronic circuit for controlling the operation of the device.

[0135] An electrical circuit includes an electrical input port, an electrical output port, and multiple electrical paths that interconnect the electrical input port and the electrical output port.

[0136] Each of the multiple power paths is an optional power path, so that only one path is activated (i.e. runs) at any given time.

[0137] Multiple power paths include DC power paths and AC power paths, which are connected in parallel but serve as alternatives to each other.

[0138] The DC power path is configured for DC power output and includes a power converter that interconnects the power input port and the power output port.

[0139] The power converter has an input side and an output side, and the output side is electrically isolated from the input side.

[0140] The example power converter is an AC-DC converter 12, which has an AC input side and a DC output side.

[0141] The AC / DC converter 12 is a general-purpose converter with a variable DC output voltage ranging from 300 volts to 850 volts and a variable DC output current of up to 30 amps. This output range covers most electric vehicles on the market.

[0142] The AC power path is configured for AC power output and operates as a low-impedance power path that interconnects the input and output sides.

[0143] An electrical circuit includes an electrical input section (or simply "input section"), which is connected to an electrical input port for receiving electrical energy from an external power source.

[0144] The input section interconnects the power input port with the input side of the power converter via an AC bus system.

[0145] The input section is a four-wire section configured for three-phase AC power input. This four-wire section includes three live conductors and one neutral conductor.

[0146] The input section includes an AC arc fault detector in the form of an arc fault miniature circuit breaker (MCB) 14A, an MCB front bus section, and an MCB rear bus section, wherein the arc fault MCB 14A interconnects the MCB front bus section and the MCB rear bus section, both of which are four-wire conductor sections.

[0147] The arc fault MCB 14A may include multiple AC arc fault circuit breakers that isolate the MCB rear bus section from the MCB front bus section when an arc fault occurs or is detected at the input section.

[0148] The DC power path includes a DC power output section (or simply "DC output section") that interconnects the output side of the power converter with the power output port. The DC output section is the DC bus section 30, which includes a positive (+ve) conductor (a high-voltage DC power conductor) and a negative (-ve) conductor (another high-voltage DC power conductor).

[0149] The AC power path includes an AC bus section 20 that interconnects the output side of the arc fault MCB 14A with the power output port. The AC bus section is a four-wire conductor segment, consisting of three live conductors and one neutral conductor.

[0150] The power input section, the power converter, and the DC bus section 30 cooperate to form a first charging path, namely the DC charging path (also known as the DC power path).

[0151] The MCB front bus section, arc fault MCB 14A, and AC bus section 20 work together to form a second charging path, namely the AC charging path (also known as the AC power path).

[0152] The AC bus section 20 is a switchable bus section, including a first AC bus segment and a second AC bus segment, which are interconnected by a switch assembly SW1 16A. The switch assembly SW1 16A can operate in a first state (which is a first switching state) or a second state (which is a second switching state).

[0153] When the switching assembly SW1 16A is in the first switching state (or "closed" state), it interconnects the first AC bus segment with the second AC bus segment to form a low-impedance AC bus section to assist the flow of AC charging energy along the AC energy path.

[0154] When the switching assembly SW1 16A is in the second switching state or the "open" state, it isolates the first AC bus segment from the second AC bus segment, thereby forming a high-impedance AC bus section, and thus isolating the power input port or power input section from the power output section.

[0155] The first AC bus section and the second AC bus section are power bus sections and have the same electrical characteristics, including voltage level, current level, insulation level, etc.

[0156] The DC bus section 30 is a switchable bus section, including a first DC bus segment and a second DC bus segment, which are interconnected by a switching assembly SW2 16B. The switching assembly SW2 16B can operate in a first state (which is a first switching state) or a second state (which is a second switching state).

[0157] When the switching assembly SW2 16B is in the first switching state or the "closed" state, it interconnects the first DC bus segment with the second DC bus segment to form a low-impedance DC bus section to assist the DC charging energy to flow along the DC energy path.

[0158] When the switching assembly SW2 16B is in the second switching state or the "open" state, it isolates the first DC bus segment from the second DC bus segment, thereby forming a high-impedance DC bus section, and thus isolating the power converter from the power output section.

[0159] The first and second DC bus sections are power bus sections and have the same electrical characteristics, including voltage level, current level, and insulation level.

[0160] The AC charging path and the DC charging path share the same input section, which includes the MCB and the MCB front bus section.

[0161] The insulation parameters and insulation status of an electric vehicle can be determined using this device (more specifically, by connecting the device to the electric vehicle in a charging connection state).

[0162] For pure electric vehicles, the key insulation parameters are those of the high-voltage DC section, including the high-voltage DC bus and battery terminals (which are high-voltage DC terminals). To meet stringent safety requirements, the high-voltage DC bus and high-voltage DC terminals are typically well-sealed and isolated.

[0163] To determine relevant or critical electrical parameters, electrical sensors 18 (such as voltage sensors and current sensors) need to be installed for purposes such as voltage sensing, current sensing, or insulation measurement.

[0164] Sensors can be installed in selected parts or sections of electrical circuits to acquire electrical parameters and monitor operating status.

[0165] For the DC output section, voltage and current sensors can be installed to detect the voltage and current of each individual DC conductor (i.e., the high-voltage DC positive conductor and the high-voltage DC negative conductor).

[0166] For the input section, voltage and current sensors can be installed to detect the voltage and current of each AC conductor (i.e., the live wire and the neutral wire) on the back of the switch and / or the input side of the power converter.

[0167] For the AC section, voltage and current sensors can be installed to detect the voltage and current of each AC conductor (i.e., the live wire and the neutral wire).

[0168] In addition to using discrete voltage and current sensors, insulation parameters can also be determined using a device called an insulation monitoring device (IMD), or a combination of both.

[0169] An insulation monitoring device (IMD) can be installed to monitor the insulation parameters of the DC output section and the AC bus section.

[0170] Insulation monitoring devices suitable for electric vehicle applications are available from sources such as Blue Jay® (GYID series IMD) and Bender.

[0171] A voltage sensor can be installed to monitor the voltage on the input side of the power converter.

[0172] Sensors and / or insulation monitoring devices (IMDs) can be configured to monitor, for example, the voltage and / or current of the high-voltage DC positive and negative conductors relative to the circuit ground (FG) to determine critical electrical parameters. A DC IMD can be used to achieve this purpose.

[0173] Sensors and / or insulation monitoring devices (IMDs) can be installed to monitor, for example, the voltage and / or current of individual AC conductors in an AC bus section relative to the circuit ground (FG) to determine critical electrical parameters. This can be achieved using an AC IMD.

[0174] The electronic circuitry includes a controller for controlling the operation of the device, including performing protocol-based data communication with the electric vehicle, controlling the switching operations of various switches, acquiring electrical parameters from various sensors, and processing electrical parameters to determine insulation parameters and / or insulation status.

[0175] Electronic circuits include data and control bus infrastructure to assist in control operations and data communication.

[0176] The device includes an arc fault detector on the output side of the power converter so that the controller can be aware of arc fault conditions.

[0177] During operation, the device is electrically coupled to the electric vehicle, for example, enabling electrical and data communication between the charging gun and the charging port, as shown in Figure 2.

[0178] Referring to Figure 3A, after the charging gun establishes electrical and data communication with the charging port in step 102, the device and the electric vehicle will initiate protocol-based communication, causing the electric vehicle to switch to charging mode (as shown in step 104). After step 104 is successfully completed, the electric vehicle will enter charging mode (as shown in step 106).

[0179] Referring to Figure 3B, through the protocol communication in step 104, the electric vehicle enters the DC charging mode, and the device will begin to perform DC charging on the electric vehicle, entering the DC charging state (as shown in step 114). Subsequently, the device will operate the sensors and / or DC IMD to acquire electrical parameters to determine the insulation characteristics (as shown in step 116).

[0180] Referring to Figure 3C, through the protocol communication in step 104, the electric vehicle enters the AC charging mode, and the device will begin performing AC charging on the electric vehicle, entering the AC charging state (as shown in step 124). Subsequently, the device will operate the sensors and / or AC IMD to acquire electrical parameters to determine the insulation characteristics (as shown in step 126).

[0181] Voltage measurement may include measuring and / or recording: the voltage between the negative side and the electrical chassis ( ), the voltage between the front and the electrical chassis ( ), and the voltage of the battery pack ( ).

[0182] like Greater than The method involves connecting a resistor of known resistance value between the negative side and the electrical chassis. ), and measure the voltage between the negative side and the electrical chassis ( The processing steps include calculating the isolation resistance according to the following formula: .

[0183] like Greater than The method includes connecting a resistor of known resistance value between the front side and the electrical chassis. ), and measure the voltage between the front side and the electrical chassis ( The processing steps include calculating the isolation resistance according to the following formula: .

[0184] resistance( It can be a built-in component of the isolation resistance measurement circuit and can be switched to connect between the positive side and the electrical chassis, or between the negative side and the electrical chassis.

[0185] When measurements are performed in battery charging mode, charging power is supplied from an external power source to the battery pack through the battery charging port.

[0186] When a measurement is performed in power output mode, power is output from the battery pack to the external load through the power output port.

[0187] The electronic circuitry is configured to monitor for arc faults, as shown in Figures 3D and 3E. When the electric vehicle is in AC charging mode 132 and AC charging state 134, the control circuitry is configured to monitor for potential arc faults via an AC arc fault detector. Upon detection of an arc fault, the arc fault MCB 14A will disconnect the AC circuit and send an alarm signal to the control circuitry. When the electric vehicle is in DC charging mode 142 and DC charging state 144, the control circuitry is configured to monitor for potential arc faults via a DC arc fault detector 14B. Upon detection of an arc fault, the arc fault detector 14B will send an alarm signal to the control circuitry, which will then disconnect the switching assembly SW216B.

[0188] Although the present invention has been described in conjunction with exemplary embodiments, these exemplary embodiments are provided to facilitate a better understanding of the present invention and should not be construed as limiting.

Claims

1. A method for measuring electrical parameters of an electric vehicle to determine insulation parameters, wherein, The vehicle includes: a battery pack for providing driving power to an electric motor that drives the electric vehicle; a power exchange port; a switchable DC bus system configured to provide a power exchange path between the battery pack and the power exchange port when the vehicle is in power exchange mode; a controller configured to perform protocol-based data communication through the power exchange port; and a vehicle chassis, which is an electrical chassis; wherein the battery pack has a high-voltage positive terminal and a high-voltage negative terminal, the high-voltage positive terminal being connected to the high-voltage positive conductor of the DC bus system to form the positive side of the DC bus system, and the high-voltage negative terminal being connected to the high-voltage negative conductor of the DC bus system to form the negative side of the DC bus system; The method includes: An electronic circuit is connected to the power exchange port, the electronic circuit including an isolation resistance measurement circuit; Establish data communication with the electric vehicle to switch the electric vehicle to power exchange mode, and connect the isolation resistance measurement circuit between the live parts of the electric vehicle and the electrical chassis; When the electric vehicle is operating in power exchange mode, voltage measurement and / or recording of voltage measurement data are performed, wherein the voltage is the voltage between the energized components and the electrical chassis; The voltage measurement data is processed to obtain insulation parameters used to determine the electrical insulation status of the electric vehicle.

2. The method according to claim 1, wherein, The high-voltage positive terminal and the high-voltage negative terminal are battery assembly terminals. When the electric vehicle is in power exchange mode, the high-voltage positive terminal and the high-voltage negative terminal form electrical communication with the power exchange port. When the electric vehicle is not in power exchange mode, one or both of the high-voltage positive terminal and the high-voltage negative terminal are isolated from the power exchange port. The method includes: Switching the electric vehicle to power exchange mode enables electrical communication between the high-voltage positive terminal or the positive side of the DC system, and the high-voltage negative terminal or the negative side of the DC system, and the corresponding terminals of the power exchange port. The voltage of the corresponding terminal relative to the electric vehicle electrical chassis is measured through the power exchange port to obtain the positive and negative voltages; The positive side voltage and the negative side voltage are processed to obtain an isolation resistor.

3. The method according to claim 1, wherein, The method includes: Switch the electric vehicle to DC charging mode, which is the battery charging mode; When the electric vehicle is in a battery charging connection and in a battery charging state, DC charging power is supplied to the electric vehicle, wherein the DC charging power flows into the battery assembly from the battery charging port, which is the power exchange port, and the DC charging power includes a positive charging voltage and a negative charging voltage relative to the electric vehicle's electrical chassis. In addition, the positive charging voltage and the negative charging voltage are measured to determine the isolation resistance and / or insulation status of the electric vehicle.

4. The method according to claim 1, wherein, The method includes: Switch the electric vehicle to AC charging mode, which is the battery charging mode; When the electric vehicle is in a battery charging connection state and in a battery charging state, AC charging power is supplied to the electric vehicle, wherein the AC charging power flows into the battery assembly from the battery charging port, which is the power exchange port, through the power converter, and the AC charging power includes at least one live conductor voltage and one neutral conductor voltage relative to the electric vehicle electrical chassis. The voltage of the live wire conductor and the voltage of the neutral wire conductor are measured to determine the isolation resistance and / or insulation status of the electric vehicle.

5. The method according to claim 4, wherein, The AC charging energy includes multiple live wire conductor voltages and one neutral wire conductor voltage relative to the electric vehicle electrical chassis; and the method includes: The voltage values ​​of the multiple live wire conductors and the voltage value of the neutral wire conductor relative to the electric vehicle electrical chassis are measured respectively to determine the isolation resistance and / or insulation status of the electric vehicle.

6. The method according to any of the preceding claims, wherein, The method includes: measuring voltage using a device that forms electrical communication with the power exchange port to determine the isolation resistance and / or insulation status of the electric vehicle, wherein the device is not a component or built-in part of the electric vehicle.

7. The method according to claim 6, wherein, The method includes coupling the device to the electric vehicle to enable data communication and electrical communication between the two.

8. The method according to claim 7, wherein, The device has electronic circuitry, electrical circuitry, and a circuit ground; and the method includes electrically connecting the circuit ground of the device to the electrical chassis of the electric vehicle to establish a common ground between the device and the electrical chassis of the electric vehicle; wherein the device has an electrical input portion for connection to a power source with a ground connection, and wherein the common ground is isolated from the ground connection; and / or wherein the device has a metal housing configured to be connected to the ground connection, and wherein the common ground is isolated from the metal housing.

9. The method according to claim 1, wherein, The isolation resistance measurement circuit includes a reference resistor ( The method includes multiple reference resistors with known resistance values, one or more insulation monitoring devices (IMDs), for switchable connection between the live parts of the electric vehicle and the electrical chassis, and wherein the method includes performing voltage measurement using the insulation monitoring device (IMD) or the multiple insulation monitoring devices (IMDs), or connecting the reference resistors (...) Voltage measurements are performed before and after the multiple reference resistors.

10. An apparatus for carrying out the method according to any of the preceding claims, wherein, The device includes electronic circuitry comprising controller circuitry and measurement circuitry; The measurement circuit includes an isolation resistance measurement circuit, which includes a voltage sensor; The controller circuit is configured as follows: The system performs protocol-based data communication with the electric vehicle to switch the electric vehicle to power exchange mode and connects the isolation resistance measurement circuit between the energized components of the electric vehicle and the electrical chassis. When the electric vehicle is operating in power exchange mode, voltage measurement and / or recording of voltage measurement data are performed, wherein the voltage is the voltage between the energized components and the electrical chassis; The voltage measurement data is processed to determine the isolation resistance and / or electrical insulation status of the electric vehicle.

11. The apparatus according to claim 10, wherein, The device is configured such that the electronic circuitry performs protocolized data communication with the electric vehicle via the electric vehicle's power exchange port, and wherein the device includes a power exchange head configured to facilitate physical connection and electrical communication with the electric vehicle via the electric vehicle's power exchange port.

12. The apparatus according to claim 11, wherein, The power exchange head of the device has a shape and layout complementary to the power exchange port of the electric vehicle, and wherein the power exchange head of the device is configured to be physically separable from the electric vehicle when the method is not implemented.

13. The apparatus according to claim 10, wherein, The device includes an electrical circuit configured to form electrical communication with the energized components of the electric vehicle through electrical coupling between the power exchange head and the power exchange port.

14. The apparatus according to claim 13, wherein, The electrical circuit includes a DC power path having a high-voltage positive conductor and a high-voltage negative conductor that are in electrical communication with the battery assembly, wherein the DC power path is configured to connect to the energized components of the electric vehicle DC bus system; and wherein a voltage sensor is provided for acquiring the positive voltage of the high-voltage positive conductor relative to the electric vehicle electrical chassis, and the negative voltage of the high-voltage negative conductor relative to the electric vehicle electrical chassis.

15. The apparatus according to claim 14, wherein, The voltage sensor includes a reference resistor ( One or more reference resistors with known resistance values ​​are used to be switchably connected between the energized component and the electrical chassis of the electric vehicle, or wherein the voltage sensor includes one or more insulation monitoring devices (IMDs).

16. The apparatus according to claim 13, wherein, The electrical circuit includes a DC power path having a high-voltage positive conductor and a high-voltage negative conductor in electrical communication with the battery assembly, and wherein an insulation monitoring device (IMD) is provided for acquiring the positive voltage of the high-voltage positive conductor relative to the electric vehicle electrical chassis and the negative voltage of the high-voltage negative conductor relative to the electric vehicle electrical chassis.

17. The apparatus according to claim 13, wherein, The power circuit includes a power input port, a power output port, and an AC / DC power converter connecting the power input port and the power output port to form a DC power path. The AC / DC power converter has a power input side connected to the power input port and a power output side connected to the power output section, and the power input side and the power output side are electrically isolated.

18. The apparatus according to claim 13, wherein, The electrical circuit includes an electrical input port, an electrical output port, and at least one electrical path connecting the electrical input port and the electrical output port; wherein the electrical input port is configured to be connected to a power source having an electrical ground, and the electronic circuit has a circuit ground isolated from the electrical ground; and wherein the device includes a connection port for establishing a common electrical ground between the circuit ground and the electrical chassis of the electric vehicle.

19. The apparatus according to claim 13, wherein, The electrical circuit includes an AC power path having at least one live conductor and one neutral conductor, and wherein a voltage sensor or insulation monitoring device (IMD) is provided to obtain the voltage of the live conductor relative to the electric vehicle electrical chassis and the voltage of the neutral conductor relative to the electric vehicle electrical chassis.

20. The apparatus according to any of the preceding claims, wherein, The device is configured as a charger for charging the battery pack of the electric vehicle, and the electronic circuitry includes a controller configured to perform protocolized data communication with the electric vehicle, switch the electric vehicle to a battery charging mode, and collect electrical parameters for determining the insulation parameters of the electric vehicle through the charging port of the electric vehicle.

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