Electric vehicle, on-board charger, method and computer program

Abstract

An electric vehicle is provided that includes an electrical circuitry. The electrical circuitry includes a battery and an on-board charger. The battery is configured to store electrical energy. The on-board charger and the battery are arranged to form a DC circuit for transmitting electrical energy as DC power between the on-board charger and the battery. The on-board charger is configured to convert the electrical energy between the DC power and AC power. The on-board charger is configured to be coupled to an external electrical circuit to form an AC circuit for transmitting electrical energy as AC power between the on-board charger and the external electrical circuit. The on-board charger is configured to detect an arc fault in the AC circuit.

Description

[Technical field]

[0001] The present invention relates to an electric vehicle having an on-board charger. The present invention further relates to an on-board charger for use with an electric vehicle. The present invention further relates to a method for detecting arc faults using an electric vehicle. The present invention further relates to a computer program having instructions to be executed by a computing device of an on-board charger. [Background technology]

[0002] An electric vehicle is a vehicle that uses electrical energy to drive a motor to propel the vehicle. Typically, an electric vehicle is provided with a battery to store the electrical energy. To charge the battery, the electric vehicle is provided with a coupling device to connect the vehicle to a power grid. When the vehicle is parked, for example at home or in a parking lot, connecting the vehicle to the power grid allows the battery to be charged.

[0003] Batteries require electrical energy to be provided as DC power in order to store it. Batteries also provide electrical energy as DC power. However, the power grid provides electrical energy as AC power, typically at 110V or 230V with a frequency of 50Hz or 60Hz. To convert AC power to DC power, electric vehicles have on-board chargers.

[0004] The on-board charger has two main functions. The first function is to convert AC power from the power grid into DC power so the battery can store electrical energy. The second function is that the on-board charger controls the amount of DC power that is directed to the battery. For example, the on-board charger limits the amount of current through the battery or reduces the voltage of the DC power if the battery has a low state of charge. Because the on-board charger is located on the electric vehicle, the electric vehicle does not depend on the presence of a dedicated charger at the charging location. Instead, a periodic connection to the power grid is sufficient to charge the battery using the on-board charger.

[0005] Electrical circuits can suffer from arcing faults. An arcing fault is a high power discharge between two or more conductors. A common cause of such a discharge is a damaged wire in an electrical circuit. If the insulation layer of two adjacent wires is damaged, the voltage difference between the two wires can cause a discharge between the two wires. Another common cause of an arcing fault is a poor electrical connection in an electrical circuit. A poor electrical connection can cause the electrical circuit to repeatedly break and reconnect. The voltage on the electrical connection can cause an arc in the electrical connection. An arcing fault can cause a large amount of heat, causing further damage to the wires and electrical connections. An arcing fault can lead to a fire.

[0006] Even if an arc fault occurs, this will not trip a fuse or an earth leakage current interrupter. Even though an arc fault generates a lot of heat, the current caused by an arc fault is typically not enough to exceed the fuse threshold. Also, an arc fault does not lead to any event that would trip an earth leakage current interrupter.

[0007] Dedicated arc fault protection devices are available for protecting electrical circuits from arc faults. A known arc fault protection device is disclosed in US Pat. No. 6,414,829. The known arc fault protection device is located in a fuse box. The fuse box is connected to a power grid. Power is provided from the fuse box to an outlet through the arc fault protection device. If a device connected to the outlet experiences an arc fault, the arc fault protection device will simulate a ground fault and cause a ground fault circuit breaker to interrupt the electrical circuit.

[0008] Despite the safety features of arc fault protection devices, they are not very common in many countries, and if people want to use arc fault protection devices in their homes, they will often need to replace the fuse boxes in their homes. Such replacements are costly. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] U.S. Patent No. 6,414,829 Summary of the Invention [Problem to be solved by the invention]

[0010] It is an object of the present invention to provide an electric vehicle with an on-board charger that increases the safety of the electrical circuits involved in charging the electric vehicle's battery, or at least to provide an alternative. [Means for solving the problem]

[0011] The object of the invention is achieved by an electric vehicle comprising an electrical circuitry. The electrical circuitry comprises a battery and an on-board charger. The battery is configured to store electrical energy. The on-board charger and the battery are arranged to form a DC circuit for transmitting electrical energy as DC power between the on-board charger and the battery. The on-board charger is configured to convert the electrical energy between the DC power and AC power. The on-board charger is configured to be coupled to an external electrical circuit to form an AC circuit for transmitting electrical energy as AC power between the on-board charger and the external electrical circuit. The on-board charger is configured to detect arc faults in the AC circuit.

[0012] If an arc fault occurs in the external electric circuit, the arc fault will cause a voltage and / or current fluctuation in the external electric circuit. There are many causes for the voltage and / or current fluctuation in the external electric circuit. For example, switching on or off a high power device coupled to the external electric circuit will cause a fluctuation. For example, a sudden increase or decrease in the power provided by a solar panel coupled to the external electric circuit will cause a fluctuation. However, despite all these fluctuations, the fluctuation caused by the arc fault will have a typical frequency component or a typical time-dependent fluctuation. Since the on-board charger is coupled to the external electric circuit, the arc fault occurring in the external electric circuit will be visible in the AC circuit. As a result, the arc fault will be visible to the on-board charger. The on-board charger is configured to identify the fluctuation caused by the arc fault. In this way, the on-board charger can detect the arc fault in the external electric circuit and improve the safety of the external electric circuit. The safety is improved without the need to adjust the fuse box of the external electric circuit. The safety is improved by simply coupling the electric vehicle to the external electric circuit. After the on-board charger detects an arc fault, the external electrical circuit may need to be repaired to prevent the arc fault from occurring in the future, for example, damaged wiring in the external electrical circuit is replaced or electrical connections are properly reconnected.

[0013] The electric vehicle is, for example, a land vehicle such as a car, a bus, or a truck. The electric vehicle is, for example, a watercraft such as a boat, a ship, or a ship. The electric vehicle has at least one electric motor to propel the vehicle. For example, the electric motor is adapted to propel the vehicle via a propeller, a screw, or a wheel. For example, the vehicle has multiple electric motors. For example, each of the multiple electric motors is coupled to a corresponding wheel to drive the corresponding wheel. For example, the electric motor is an in-wheel motor. The electric vehicle has a battery to provide electric energy to the electric motor. For example, the vehicle has a fuel tank, a combustion engine, and a generator in addition to the battery. The combustion engine is configured to burn fuel from the fuel tank to drive the generator. The generator is configured to generate electric energy. The generator provides electric energy to the battery, to the electric motor, or to both the battery and the electric motor. The electric vehicle is, for example, an electric bicycle. The electric bicycle has an electric motor to provide a portion of the power to propel the electric bicycle. The electric bicycle has pedals coupled to the wheels of the electric bicycle to provide additional power to propel the electric bicycle.

[0014] The electrical network includes a battery and an on-board charger. The electrical network is, for example, a single electrical circuit or a system of multiple electrical circuits coupled together. The electrical network includes, for example, safety devices, such as fuses or circuit breakers. The electrical network includes, for example, various other electrical components. Such electrical components are, for example, drive train components for driving the vehicle, such as an inverter configured to convert DC power provided by the battery back to AC power required by the electric motor. The electrical network includes, for example, devices for use in the passenger compartment of the vehicle, such as a radio or dashboard display or electric windows. The electrical network includes, for example, various electrical controllers, such as, for example, a cruise control system configured to control the speed of the electric vehicle, or a thermal control system configured to control the temperature of the vehicle, or an emergency brake control system configured to control the brakes of the vehicle in an emergency. The electrical network provides, for example, electrical energy at different voltages to electrical components in the electric vehicle.

[0015] The battery is configured to store electrical energy. For example, the battery is a lithium ion (Li-Ion) battery, a molten salt (Na-NiCl2) battery, a nickel metal hydride (Ni-MH) battery, or a lithium sulfur (Li-S) battery. The battery may be, for example, a single battery, or may comprise multiple batteries. The multiple batteries may be, for example, electrically arranged in parallel, in series, or in a combination of parallel and series. The multiple batteries may have the same maximum voltage or different maximum voltages. For example, an electric vehicle may have a low voltage battery and a high voltage battery. The low voltage battery may have a maximum voltage of, for example, 5V or 12V or 48V. The high voltage battery may have a maximum voltage of, for example, 60V or 300V or 400V. For example, the high voltage battery may provide electrical energy to the drive train of the electric vehicle, such as the electric motor. For example, the low voltage battery may provide electrical energy to auxiliary components of the electric vehicle, such as the HVAC system and the lighting system.

[0016] The on-board charger is configured to convert electrical energy between DC power and AC power. When the battery is charged with electrical energy from an external electrical circuit, the on-board charger converts the AC power from the external electrical circuit into DC power and provides the electrical energy as DC power to the battery. The on-board charger is configured to safely charge the battery. For example, the on-board charger limits a maximum current through the battery. For example, the on-board charger adjusts a voltage of the DC power in response to a voltage of the battery. If the battery has a low charge state, the voltage of the battery may be low. If the DC power is too high, the current through the battery may be too high. The on-board charger is configured to adjust a voltage of the DC power to an allowed voltage. For example, the on-board charger is configured to provide electrical energy to multiple batteries. For example, the on-board charger has multiple DC power outputs to provide electrical energy to multiple batteries. For example, each DC power output has a different voltage than the other DC power outputs.

[0017] In one example, the on-board charger is configured to transfer electrical energy from a battery to an external electrical circuit. For example, an electric vehicle includes a solar panel. When the electric vehicle does not require electrical energy from the solar panel, for example when the battery is fully charged, the electrical energy from the solar panel is transferred to the external electrical circuit. To do this, the on-board charger converts the electrical energy from the battery from DC power to AC power. The electrical energy as AC power is then transferred to the external electrical circuit.

[0018] The external electric circuit is referred to as "external" because it is an electric circuit that does not form part of the vehicle. The external electric circuit is an AC circuit. The external electric circuit has a phase wire, a neutral wire and a ground wire. An AC voltage is applied to the phase wire. When the AC circuit is closed, a current runs in the AC circuit. The current runs through the phase wire and the neutral wire. The ground wire is connected to ground. The external electric circuit is, for example, the electric circuit of a house. The external electric circuit is, for example, the electric circuit of a public charging station. The external electric circuit is, for example, connected to a power grid. The external electric circuit has safety mechanisms such as a circuit breaker and a ground fault circuit interrupter circuit. The circuit breaker interrupts the external electric circuit if the current through the circuit breaker exceeds a threshold value. The ground fault circuit interrupts the external electric circuit if a voltage or current is applied to the ground wire.

[0019] The voltage amplitude and phase of the AC power are determined, for example, by an external electric circuit. When the on-board charger is configured to provide electric energy as AC power to the external electric circuit, the on-board charger is configured to adapt the voltage amplitude and phase of the AC power to the external electric circuit.

[0020] In one embodiment, the on-board charger is configured to detect arc faults in the external electrical circuit.

[0021] According to the above embodiment, the on-board charger is configured to detect arc faults outside the vehicle. When the on-board charger is coupled to an external electrical circuit, the on-board charger can detect arc faults occurring in the external electrical circuit. In this way, arc faults can be detected every time the vehicle is coupled to an external electrical circuit, even when the external electrical circuit is not provided with an arc fault detector.

[0022] In one embodiment, the on-board charger is configured to trip a safety mechanism in an external electrical circuit upon detecting an arc fault.

[0023] According to the above embodiment, the external electric circuit has a safety mechanism, such as a fuse or a circuit breaker or a ground fault circuit interrupter or a combination thereof. All or almost all electric circuits suitable for charging the battery of an electric vehicle are provided with one or more of such safety mechanisms. Such electric circuits are typically required to have the safety mechanism due to safety regulations. Such safety regulations require that electric circuits in residential and office buildings are provided with circuit breakers and ground fault circuit interrupters. An example of such a safety regulation is the Dutch NEN1010 regulation. The on-board charger utilizes the safety mechanism of the external electric circuit. When the on-board charger detects an arc fault in the external electric circuit, the on-board charger trips the safety mechanism. This leads to the interruption of the external electric circuit. Due to the interruption, the arc fault is no longer present. In this way, damage caused by the arc fault is prevented or limited. In most electric circuits, the safety mechanism is located in an upstream position of the external electric circuit, for example in a fuse box where the main power line is connected to various groups of electric circuits. The safety mechanism is placed in an upstream position to ensure that if the safety mechanism is tripped, most or all of the electric circuits are interrupted. By interrupting most or all of the electrical circuit, no voltage is applied to the electrical circuit, or at least a large portion of it. By interrupting most or all of the electrical circuit, no current flows through the electrical circuit, or at least a large portion of it. Because the on-board charger trips a safety mechanism when it detects an arc fault, it is very likely that the portion of the external electrical circuit where the arc fault occurred will be interrupted. Due to the interruption, the arc fault will no longer occur. If the on-board charger only isolates itself from the external electrical circuit when it detects an arc fault in the external electrical circuit, it is very likely that the arc fault will be maintained even if the on-board charger is isolated from the external electrical circuit.

[0024] In one embodiment, the on-board charger is configured to trip a safety mechanism in an external electrical circuit by creating a short circuit in the AC circuit.

[0025] According to the above embodiment, if the on-board charger detects an arc fault in the external electric circuit, the on-board charger causes a short circuit in the AC circuit. For example, the on-board charger includes a switch adapted to couple a phase wire of the AC circuit directly to the neutral wire of the AC circuit. When the on-board charger does not detect an arc fault, the switch does not couple the phase wire to the neutral wire of the AC circuit. When the on-board charger detects an arc fault, the switch is moved to couple the phase wire to the neutral wire of the AC circuit. Due to a lack of sufficient electrical resistance, the movement of the switch causes a large current from the phase wire of the AC circuit to the neutral wire through the switch. The large current trips a circuit breaker in the external electric circuit. For example, the electrical resistance of the switch is low enough to create a large current of 16A or 20A. The on-board charger is adapted to set the switch for a small amount of time to a setting that couples the phase wire to the neutral wire of the AC circuit, for example. The small amount of time is sufficient to trip a circuit breaker of the external electric circuit. However, if the circuit breaker does not operate, the small amount of time is small enough to prevent damage from a short circuit. For example, an on-board charger is adapted to couple a phase to the neutral of an AC circuit via a switch for less than 1 second, e.g., less than 300 ms, or less than 90 ms, or less than 20 ms.

[0026] In one embodiment, the on-board charger is configured to be coupled to a ground conductor of an external electrical circuit, and the on-board charger is configured to trip the safety mechanism by providing a current and / or voltage to the ground conductor.

[0027] According to this embodiment, the on-board charger can be coupled to a ground wire of an external electric circuit. During normal operation of the external electric circuit, no voltage and current are provided to the ground wire. During normal operation, voltage and current are applied using the phase and neutral wires of the external electric circuit. When the on-board charger detects an arc fault in the external electric circuit, the on-board charger provides a current and / or voltage to the ground wire. For example, the on-board charger has a switch adapted to couple a phase wire of the AC circuit to a ground wire of the AC circuit. When the on-board charger does not detect an arc fault, the switch does not couple the phase wire to the ground wire of the AC circuit. When the on-board charger detects an arc fault, the switch is moved to couple the phase wire to the ground wire of the AC circuit. This causes a current to flow in the ground wire. Due to the current through the ground wire, a difference is caused between the current through the phase wire and the current through the neutral wire. The difference trips a ground-fault circuit breaker of the external electric circuit. Tripping of the ground-fault circuit breaker interrupts the external electric circuit. In another example, the on-board charger has a switch adapted to couple the neutral conductor of the AC circuit to the ground conductor of the AC circuit. When the on-board charger detects an arc fault, the switch is moved to couple the neutral conductor to the ground conductor of the AC circuit. This causes a current to flow in the ground conductor. The current through the ground conductor causes a difference between the current through the phase conductors and the current through the neutral conductor. The difference trips a ground-fault circuit breaker in the external electrical circuit. Tripping of the ground-fault circuit breaker interrupts the external electrical circuit.

[0028] In one embodiment, the on-board charger comprises a low pass filter for filtering the AC power signal received by the charger from the external electric circuit. In particular, the low pass filter can be arranged in the AC circuit formed. In such an embodiment, the detection of an arc fault by the on-board charger can occur upstream of the low pass filter (330). Upstream within the meaning of the present invention refers to the direction from the on-board charger towards the external electric circuit.

[0029] In one embodiment, the on-board charger includes a sensor configured to generate a signal based on a property of the AC circuit, and the on-board charger is configured to detect an arc fault based on the signal.

[0030] According to the above embodiment, the sensor of the on-board charger is arranged to determine the nature of the AC circuit. For example, the sensor is arranged in a part of the on-board charger through which the AC current flows. The AC current originates from the AC circuit. For example, the sensor is arranged in a part of the on-board charger to which the AC voltage is applied. For example, the sensor is coupled to a phase wire and / or a neutral wire of the on-board charger. The phase wire of the on-board charger is arranged to couple to a phase wire of the external electric circuit. The neutral wire of the on-board charger is arranged to couple to a neutral wire of the external electric circuit. If the on-board charger comprises a low pass filter, the above-mentioned sensor can be arranged, for example, upstream of the low pass filter.

[0031] In one embodiment, the on-board charger is configured to convert electrical energy between DC power and AC power under the control of a signal from the sensor.

[0032] In this embodiment, the on-board charger uses the sensor for additional purposes than detecting arc faults. The on-board charger determines how to convert electrical energy between DC power and AC power based on the signal from the sensor. For example, based on the signal from the sensor, the on-board charger determines the amount of AC power being received from the external electric circuit. The on-board charger generates, for example, the same amount of DC power. In another example, the on-board charger determines the amount of AC power being received from the external electric circuit via the signal from the sensor and decides to generate a low amount of DC power. For example, when the battery has a low charge state, the low amount of DC power prevents an excessively high DC current that may damage the battery. In yet another example, the signal of the sensor indicates a certain value of the amplitude of the AC voltage. Based on the signal of the sensor, the on-board charger converts the DC power to AC power of an appropriate amplitude. The sensor is, for example, a voltage sensor or a current sensor. The amount of AC power may be determined based on information of the voltage and / or current of the AC circuit. The on-board charger compares the amount of received AC power with the desired DC power to charge the battery. If the temperature of the battery becomes too high, the on-board charger may decide to reduce the desired DC power of the battery. The low DC power to the battery helps to reduce the temperature of the battery. Due to the low DC power, low AC power is desired from the external electric circuit. The on-board charger, for example, has an electrical resistor. By increasing the resistance of the electrical resistor, the on-board charger reduces the current through the AC circuit. As a result of reducing the current, the signal from the sensor changes. When the sensor provides a signal representing the desired AC power, the current through the AC circuit is no longer reduced. Thus, the on-board charger uses the sensor to control the amount of power transmitted by the on-board charger. In another example, the sensor generates a signal based on the voltage of the AC circuit. The on-board charger uses the signal to determine how to convert between DC power and AC power. If the sensor detects a voltage of 110V, the on-board charger converts the AC power to DC power differently than if the sensor detects a voltage of 220V. For example, based on the voltage detected by the sensor, the on-board charger increases or decreases the voltage of the AC power to the voltage of the DC power or vice versa.In the above examples, the on-board charger has a sensor to charge the battery or convert AC power to DC power. The same sensor can be used to determine an arc fault in an external electrical circuit. This has the advantage that no additional sensor is required.

[0033] In one embodiment, the sensor includes a current sensor configured to generate a signal based on a current in an AC circuit.

[0034] According to the above embodiment, the on-board charger has a current sensor. The on-board charger detects an arc fault based on a signal generated by the current sensor. For example, an AC current from an external electric circuit flows through a sensor in the on-board charger. When an arc fault occurs in the external electric circuit, the AC current changes. Typically, an arc fault creates a fluctuation in the AC current with a certain frequency component and / or a certain time variation. Because the current sensor can detect the AC current, the on-board charger can determine that an arc fault occurs in the external electric circuit.

[0035] In one embodiment, the sensor includes a voltage sensor configured to generate a signal based on a voltage of the AC circuit.

[0036] According to the above embodiment, the on-board charger has a voltage sensor. The on-board charger detects an arc fault based on a signal generated by the voltage sensor. For example, an AC voltage from an external electric circuit is applied to a sensor in the on-board charger. When an arc fault occurs in the external electric circuit, the AC voltage changes. Typically, the arc fault creates a fluctuation in the AC voltage with a certain frequency component and / or a certain time variation. Because the voltage sensor can detect the AC voltage, the on-board charger can determine that an arc fault occurs in the external electric circuit.

[0037] In one embodiment, the on-board charger includes a computing device configured to detect an arc fault based on the time variation of the signal and / or the frequency content of the signal.

[0038] According to the above embodiment, the computing device receives a signal from the sensor. The computing device is configured, for example, to analyze the signal. For example, the computing device is configured to perform signal processing, such as performing Fourier analysis. The computing device is configured, for example, to filter the signal from the sensor to remove or reduce components of the signal caused by causes other than the arc fault. For example, the filter may reduce or remove 50 Hz or 60 Hz of the main frequency of the AC circuit. For example, the filter reduces or removes other frequencies from the signal that are known to be caused by other causes, such as switching equipment power on and off. For example, the filter increases the amplitude of frequencies in the signal caused by the arc fault to more clearly determine when an arc fault occurs. In an AC circuit, an arc fault typically creates a repetitive arc. The repetitive arc begins when the amplitude of the AC voltage exceeds a threshold. The repetitive arc is maintained as long as the amplitude of the AC voltage exceeds the threshold and is extinguished when the amplitude of the AC voltage falls below the threshold. As a result of the repetitive arc, the current and / or voltage of the AC circuit change repetitively. The computing device is configured, for example, to identify such repetitive changes to determine the presence of an arc fault.

[0039] In one embodiment, the on-board charger is configured to generate a warning signal upon detecting an arc fault.

[0040] According to the above embodiment, the on-board charger detects the arc fault and generates a warning signal. For example, the warning signal is sent to another component arranged in the vehicle. The other component is, for example, a display. The display is, for example, visible in the passenger compartment of the vehicle. The display displays a warning indicating that an arc fault has been detected. The other component is, for example, a communication device. The communication device is configured to transmit a text message or any other type of message based on the warning signal. The communication device is configured to transmit the message to a mobile device, such as a smartphone or tablet of the owner of the vehicle. The communication device is configured to transmit the message to a display outside the vehicle. The display is, for example, electrically coupled to an external electric circuit. The display is, for example, arranged in a building having an external electric circuit. The communication device transmits the message via, for example, Wi-Fi or Bluetooth or any other type of wireless data transfer. For example, the on-board charger is provided with a communication port to receive a network cable, such as a UTP cable or an Ethernet cable. The on-board charger is adapted to transmit the warning signal via the network cable. For example, the network cable may be integrated into a plug that couples an external electrical circuit to an on-board charger.

[0041] In one embodiment, the energy in the AC power is at a first voltage. The energy in the DC power is at a second voltage. The first voltage is different from the second voltage. The on-board charger is configured to convert the energy in the AC power at the first voltage to energy in the DC power at the second voltage and / or vice versa.

[0042] According to the above embodiment, the on-board charger is configured to receive AC power of a first voltage. The first voltage has, for example, a first amplitude. The first amplitude is, for example, 110V or 220V. However, the maximum voltage of the battery of the electric vehicle is 400V. To properly charge the battery, the on-board charger can convert the voltage of the AC power to a desired high voltage of the battery. In another example, the maximum voltage of the battery is 12V. In this example, the on-board charger can convert the voltage of the AC power to a desired low voltage of the battery. In one example, the on-board charger is not only configured to convert the first voltage to a second voltage, but also configured to convert energy from the second voltage to the first voltage. In this example, the battery of the vehicle is configured to provide electrical energy to an external electric circuit. For example, if the electric vehicle has solar panels, the vehicle provides electrical energy to the external electric circuit when the battery of the vehicle is fully charged. To provide electrical energy from the battery to the external electrical circuit, the on-board charger converts DC power from the battery, which is at a second voltage, into AC power for the external electrical circuit, which is at a first voltage.

[0043] In one embodiment, the on-board charger includes a coupling device configured to electrically couple the on-board charger to an external electrical circuit.

[0044] According to the above embodiment, the on-board charger is coupled to an external electric circuit via a coupling device. The coupling device comprises, for example, a socket arranged on the vehicle which connects to a plug of the external electric circuit. The coupling device comprises, for example, a plug arranged on the vehicle which connects to the socket of the external electric circuit and a cable which is connected to the plug. The coupling device comprises, for example, an indicator light which indicates whether the vehicle is being charged. The coupling device comprises, for example, a warning light which is activated based on a warning signal.

[0045] In one embodiment, the electric vehicle includes an electric motor configured to drive the vehicle, and a battery configured to provide electrical energy to the electric motor.

[0046] According to the above embodiment, the electric vehicle is propelled by an electric motor. For example, the electric motor is a single motor that drives multiple wheels of the vehicle, for example via a gearbox and / or differential. In another example, the electric motor drives only a single wheel. For example, the electric motor is an in-wheel motor, alternatively known as a hub motor. An in-wheel motor is integrated into a wheel of the vehicle. A battery provides electrical energy to operate the electric motor. The electrical energy from the battery is transformed, for example, before being received by the electric motor. For example, the vehicle includes an inverter that transforms the electrical energy of the battery, which is DC power, back to electrical energy, which is AC power.

[0047] In a second aspect of the present invention, there is provided an on-board charger for use with an electric vehicle according to any one of the above-mentioned embodiments. The on-board charger is configured to convert electrical energy between DC power and AC power. The on-board charger is configured to be coupled to an external electrical circuit to form an AC circuit for transmitting electrical energy as AC power between the on-board charger and the external electrical circuit. The on-board charger is configured to detect arc faults in the AC circuit.

[0048] According to a second aspect, the on-board charger is configured to convert electrical energy between DC power and AC power. The on-board charger is configured to convert electrical energy from DC power to AC power, from AC power to DC power, or from DC power to AC power and from AC power to DC power. The on-board charger is configured to be coupled to an external electrical circuit, for example directly or indirectly via one or more other electrical components. When coupled to the external electrical circuit, the on-board charger and the external electrical circuit together form an AC circuit. The electrical energy as AC power is transferred from the external electrical circuit to the on-board charger, from the on-board charger to the external electrical circuit, or alternatively from the external electrical circuit to the on-board charger and from the on-board charger to the external electrical circuit.

[0049] In one embodiment, the on-board charger is configured to detect arc faults in the external electrical circuit.

[0050] In one embodiment, the on-board charger is configured to trip a safety mechanism in an external electrical circuit upon detecting an arc fault.

[0051] In a third aspect of the present invention, a method for detecting an arc fault using an electric vehicle is provided. The electric vehicle includes an electrical network and a sensor. The method includes: - connecting the electrical network to an external electrical circuit to form an AC circuit; - generating a signal at a sensor based on a current and / or a voltage in an AC circuit; - detecting an arc fault in the AC circuit based on the signal.

[0052] According to a third aspect, an electric vehicle is used to detect arc faults in an external electric circuit. The external electric circuit does not form part of the electric vehicle. In this way, it is possible to detect arc faults in the external electric circuit simply by connecting the electric vehicle via an on-board charger to the external electric circuit. The external electric circuit does not need to have its own arc fault detector.

[0053] In one embodiment, the method comprises: - transmitting energy between the electrical network and an external electrical circuit under control of a signal from the sensor.

[0054] According to the above embodiment, the sensor provided a signal based on the current and / or voltage of the AC circuit. Based on the signal, energy is transmitted between the electric circuit and an external electric circuit. For example, the signal indicates the AC voltage of the external electric circuit, and the energy is transmitted at the same AC voltage. For example, the sensor indicates a very high AC current through the external electric circuit, and the energy is transmitted at a current smaller than the AC current to prevent damage to the electric circuit network.

[0055] In one embodiment, the method comprises: - tripping a safety mechanism of an external electrical circuit in the electrical network.

[0056] According to the above embodiment, the external electric circuit has a safety mechanism, such as a fuse or a circuit breaker or a ground fault circuit interrupter or a combination thereof. Most or all of the electric circuits suitable for charging the battery of an electric vehicle are provided with one or more of such safety mechanisms. Such electric circuits are required to have the safety mechanism due to safety regulations. Such safety regulations make circuit breakers and ground fault circuit interrupters mandatory for electric circuits in residential and office buildings. When an arc fault is detected in the external electric circuit, the safety mechanism is tripped. This leads to the interruption of the external electric circuit. Due to the interruption, the arc fault is no longer present. In this way, damage caused by the arc fault is prevented or limited. In most electric circuits, the safety mechanism is located at an upstream position of the external electric circuit, for example in a fuse box where the main power line is connected to various groups of electric circuits. The safety mechanism is placed at an upstream position to ensure that most or all of the electric circuits are interrupted if the safety mechanism is tripped. By interrupting most or all of the electric circuits, no voltage is applied to the electric circuit anymore, or at least across most of it. By interrupting most or all of the electrical circuit, current no longer flows in the electrical circuit, or at least through most of it. As a result, the portion of the external electrical circuit where the arc fault occurred is most likely interrupted. The interruption causes the arc fault to disappear, thus preventing further damage. The external electrical circuit may need to be repaired to prevent future arc faults. For example, damaged wiring in the external electrical circuit is replaced or electrical connections are properly reconnected.

[0057] In one embodiment, the method comprises: - Including the step of shorting the AC circuit.

[0058] According to the above embodiment, the AC circuit is short-circuited when an arc fault is detected. The external electric circuit has a safety mechanism that protects the external electric circuit in case of a short circuit. Without such a safety mechanism, a short circuit can easily lead to a fire and / or destroy a part of the external electric circuit. Safety mechanisms that protect against short circuits are very common and mandatory in most applications, especially for electric circuits with voltages of 50V and above. Such safety mechanisms include fuses and circuit breakers. Short-circuiting the AC circuit causes the tripping of the safety mechanism. By tripping the safety mechanism, the external electric circuit is interrupted to extinguish the arc fault.

[0059] In a fourth aspect of the invention, when executed by a computing device of an on-board charger coupled to an external electrical circuit to form an AC circuit, the on-board charger is caused to: - generating a signal based on a current and / or a voltage in an AC circuit; - detecting an arc fault in the AC circuit based on the signal.

[0060] According to a fourth aspect, an on-board charger is coupled to an external electric circuit to form an AC circuit. A computer program is executed by a computing device. When the computing device executes the computer program, the on-board charger is controlled to generate a signal based on a current and / or a voltage in the AC circuit. For example, the on-board charger has a sensor that generates a signal based on a current and / or a voltage in the AC circuit. When the computing device executes the computer program, the on-board charger is controlled to detect an arc fault in the AC circuit based on the signal. For example, the computing device is configured to detect an arc fault based on signal processing of a signal from the sensor.

[0061] In one embodiment, the computer program comprises: - Performing steps to trip a safety mechanism in an external electrical circuit.

[0062] According to the above embodiment, when the computing device executes the computer program, the on-board charger trips a safety mechanism when an arc fault is detected. For example, the on-board charger moves a switch to cause a short circuit in the AC circuit. In one example, the on-board charger moves a switch to allow current to flow to the ground wire.

[0063] In one embodiment, the step of detecting an arc fault in the AC circuit based on the signal includes: - detecting variations in the signal over time, and / or - detecting the frequency content of the signal.

[0064] According to the above embodiment, when the computing device executes the computer program, the on-board charger can detect fluctuations in the signal from the sensor and / or detect the frequency content of the signal of the sensor. Based on the fluctuations and / or the frequency content, the on-board charger can determine whether an arc fault has occurred.

[0065] In one embodiment, when executed by a computing device, the computer program causes the on-board charger to: - generating a warning signal upon detection of an arc fault;

[0066] The invention will be described in more detail below with reference to the figures, in which embodiments of the invention are illustrated. [Brief description of the drawings]

[0067] [Figure 1] 1 is a diagram showing a vehicle according to an embodiment of the present invention; [Diagram 2] 1 is a diagram showing an on-board charger according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a diagram showing details of an on-board charger according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the time variation of a signal measured in an on-board charger according to an embodiment of the present invention. [Diagram 5] FIG. 4 is a diagram showing frequency components of a signal measured by an on-board charger according to an embodiment of the present invention. [Figure 6] FIG. 4 illustrates a method according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0068] FIG. 1 illustrates a vehicle 100 according to an embodiment of the present invention. The electric vehicle 100 includes an electrical circuitry 102. The electrical circuitry 102 includes a battery 104 and an on-board charger 106. The battery 104 is configured to store electrical energy. The electric vehicle 100 has four wheels and four electric motors 131-134. Each of the electric motors 131-134 is coupled to one of the four wheels. Each of the electric motors 131-134 drives one of the four wheels. The battery 104 is connected to the electric motors 131-134 and provides electrical energy to the electric motors 131-134 to drive the electric vehicle 100.

[0069] The on-board charger 106 includes a coupling device 110. The coupling device 110 is configured to electrically couple the on-board charger 106 to an external electric circuit 120. The external electric circuit 120 includes a fuse box 122, AC wiring 126, and a charging station 124. The AC wiring 126 connects the fuse box 122 and the charging station 124 to each other. Electrical energy is provided from the fuse box 122 to the charging station 124 via the AC wiring 126.

[0070] FIG. 2 illustrates a schematic diagram of an on-board charger 106 according to an embodiment of the present invention. The on-board charger 106 and the battery 104 are arranged to form a DC circuit 230 for transmitting electric energy as DC power between the on-board charger 106 and the battery 104. The DC power through the DC circuit 230 is characterized by a DC voltage and a DC current. A coupling interface 210 is connected to the charging station 124. The coupling interface 210 is adapted to couple with a coupling device 110 of the electric vehicle 100. For example, the coupling interface 210 is a plug while the coupling device 110 is a socket, or vice versa. The coupling interface 210 is connected to the charging station 124 via an electric wire.

[0071] When coupled together, the fuse box 122, the AC wiring 126, the charging station 124, the coupling interface 210, the coupling device 110, and the on-board charger 106 form an AC circuit 220. The AC power through the AC circuit 220 is characterized by an AC voltage and an AC current. The on-board charger 106 is configured to transfer electrical energy between the on-board charger 106 and the external electrical circuit 120 as AC power.

[0072] A portion of the on-board charger 106 forms part of the DC circuit 230, while another portion of the on-board charger 106 forms part of the AC circuit 220. The on-board charger 106 is configured to convert electrical energy between DC power and AC power.

[0073] The AC wiring 126 has a phase wire 241, a neutral wire 242, and a ground wire 243. In the AC circuit 220, an AC voltage is applied to the phase wire 241. The DC wiring 236 has a positive DC wire 244 and a negative DC wire 245.

[0074] When the electric vehicle 100 is coupled to the external electric circuit 120 and the on-board charger 106 charges the battery 104 with electric energy from the external electric circuit 120, an AC current flows through the phase wire 241 and the neutral wire 242. The on-board charger 106 converts AC power, which is characterized by an AC voltage and an AC current, in the AC circuit 220. The on-board charger 106 converts the AC power to DC power. The energy in the AC power is at a first voltage. The on-board charger 106 is configured to convert the energy in the AC power, which is at the first voltage, to energy in the DC power, which is at a second voltage. The second voltage is a voltage that is suitable for charging the battery 104. The second voltage is a DC voltage. When the on-board charger 106 converts the AC power to DC power, a DC current flows through the positive DC wire 244 and the negative DC wire 245 of the DC wiring 236. The DC power is characterized by a DC voltage and a DC current.

[0075] When the electric vehicle 100 is coupled to the external electric circuit 120, the battery 104 may be used to provide electric energy to the external electric circuit 120. In this case, a DC current flows in the DC circuit 230 at a DC voltage. The on-board charger 106 converts the DC power, characterized by a DC voltage and a DC current, in the DC circuit 230 to AC power. The on-board charger 106 is configured to convert the DC power at the DC voltage to AC power at an AC voltage. The AC voltage is a voltage that is suitable for use in the external electric circuit 120. Once the on-board charger 106 converts the DC power to AC power, an AC current flows through the phase wire 241 and the neutral wire 242. The AC power is characterized by an AC voltage and an AC current.

[0076] The external electrical circuit 120 may experience an arc fault 250. The arc fault 250 may be caused, for example, by a poor connection in the external electrical circuit 120 or by damage to the electrical insulation of the AC wiring 126. The arc fault 250 causes a change in the AC voltage and / or AC current in the AC circuit 220. Because the on-board charger 106 forms part of the AC circuit 220, the on-board charger 106 may detect the arc fault 250.

[0077] 3 illustrates details of the on-board charger 106 according to an embodiment of the present invention. The on-board charger 106 includes a power converter 300, a first switch 301, a second switch 302, a voltage sensor 304, a current sensor 306, and a computing device 310.

[0078] The power converter 300 is connected to the phase wires 241 and neutral wire 242 of the AC circuit 220 to receive AC power from the external electric circuit 120. The power converter 300 is also connected to the ground wire 243 of the AC circuit 220. The power converter 300 is connected to the positive DC wire 244 and negative DC wire 245 of the DC circuit 230 to provide DC power to the battery 104. The power converter 300 is configured to convert the AC power to DC power. Optionally, the power converter 300 is configured to convert the DC power from the DC circuit 230 to AC power for the AC circuit 220.

[0079] The current sensor 306 is disposed on the phase wire 241. The current sensor 306 receives an AC current from the AC circuit 220 when the battery 104 is being charged. The current sensor 306 is configured to generate a signal based on the AC current in the AC circuit 220. When an arc fault 250 occurs in the external electric circuit 120, the current sensor 306 detects a change in a characteristic of the AC current. The current sensor 306 generates a signal based on the change in the characteristic of the AC current.

[0080] The voltage sensor 304 is disposed between the phase wire 241 and the neutral wire 242 to detect an AC voltage between the phase wire 241 and the neutral wire 242. The voltage sensor 304 is configured to generate a signal based on the AC voltage of the AC circuit 220. The voltage sensor 304 can detect the AC voltage even when no energy is being transferred between the on-board charger 106 and the external electric circuit 120. When an arc fault 250 occurs in the external electric circuit 120, the voltage sensor 304 detects a change in a characteristic of the AC voltage. The voltage sensor 304 generates a signal based on the change in the characteristic of the AC voltage.

[0081] Optionally, the on-board charger 106 comprises a low pass filter 330 configured to filter the AC power signal received by the on-board charger 106, i.e., the AC power from the external circuit 120. In the illustrated arrangement, the low pass filter 330 is located upstream of the power converter 300 and downstream of the voltage sensor 304 and the current sensor 306. In the illustrated embodiment, the low pass filter (330) is therefore located in the AC circuit 220.

[0082] Optionally, the on-board charger 106 converts electrical energy between DC and AC power under the control of signals from the voltage sensor 304 and / or the current sensor 306 .

[0083] The computing device 310 is configured to detect the arc fault 250 based on the time variation of the signal and / or the frequency content of the signal. The computing device 310 receives a signal from the current sensor 306, a signal from the voltage sensor 304, or both the current sensor 306 and the voltage sensor 304. The computing device 310 performs signal processing on the one or more signals to determine if an arc fault 250 has occurred. In this manner, the on-board charger 106 is configured to detect an arc fault 250 in the external electrical circuit 120.

[0084] If the on-board charger 106 detects an arc fault 250, the on-board charger 106 trips a safety mechanism of the external electrical circuit 120. When the on-board charger 106 detects an arc fault 250, the on-board charger 106 moves the first switch 301 from an open position to a closed position. In the open position, the first switch 301 does not connect the ground wire 243 to the phase wire 241. In the closed position, the first switch 301 connects the ground wire 243 to the phase wire 241. When the first switch 301 is in the closed position, the phase wire 241 is connected to the ground wire 243, so that a current begins to flow from the phase wire 241 to the ground wire 243. As a result, the current through the phase wire 241 becomes different from the current through the neutral wire 242. A ground fault interrupter circuit in the fuse box 122 of the external electrical circuit 120 detects the difference between the currents through the phase wire 241 and the neutral wire 242. As a result, the ground fault interrupter circuit interrupts the external electrical circuit 120 .

[0085] In addition to or alternatively to moving the first switch 301, when the on-board charger 106 detects the arc fault 250, the on-board charger 106 moves the second switch 302 from an open position to a closed position. In the open position, the second switch 302 does not connect the neutral 242 to the phase 241. In the closed position, the second switch 302 connects the neutral 242 to the phase 241. With the second switch 302 in the closed position, the phase 241 is directly connected to the neutral 242, so that the AC circuit 220 is shorted. A large current flows from the phase 241 through the second switch 302 to the neutral 242. The large current increases to a value that causes a circuit breaker or fuse in the fuse box 122 of the external electrical circuit 120 to interrupt the external electrical circuit 120.

[0086] The on-board charger 106 is configured to generate a warning signal upon detecting the arc fault 250. The on-board charger 106 includes a communication device 320. When the on-board charger 106 detects the arc fault 250, the communication device 320 transmits the warning signal. The communication device 320 transmits the warning signal to, for example, a display or a mobile device to alert a user of the vehicle 100 that the arc fault 250 has occurred. The warning signal indicates, for example, that an arc fault has been detected and that an electrician should investigate the external electrical circuit to find the cause of the arc fault.

[0087] FIG. 4 illustrates the time variation of a signal measured in the on-board charger 106 according to an embodiment of the present invention. FIG. 4 illustrates a graph of values ​​representing time on the x-axis and voltage on the y-axis. The graph illustrates a signal provided by the voltage sensor 304 measuring the AC voltage of the AC circuit 220. The voltage values ​​were represented as normalized values ​​between −1 and +1. Depending on the voltage of the AC circuit 220, the voltage may range from −110V to +110V, from −220V to +220V, from −340V to +340V, or any other suitable range. The time on the x-axis is shown to increase moving from left to right along the graph. The time values ​​depend on the main frequency of the AC voltage, for example 50Hz or 60Hz or any other suitable frequency.

[0088] The graph illustrates a time period 400 during which no arc fault occurs. During time period 400, the voltage sensor 304 measures a voltage that changes over time in a sinusoidal shape. Some small variations on the sinusoidal shape may occur. During time period 410, an arc fault 250 occurs. As is evident from the graph, the sinusoidal shape changes to include disturbances 411. These disturbances 411 are typical of an arc fault 250. By detecting the disturbances 411 with the voltage sensor 304, the on-board charger 106 is able to detect the arc fault 250.

[0089] FIG. 5 illustrates the frequency components of a signal measured by the on-board charger 106 according to an embodiment of the present invention. FIG. 5 illustrates a graph of frequency on the x-axis and the magnitude of those frequencies on the y-axis. The graph represents the frequency components of a signal provided by the voltage sensor 304, which measures the AC voltage of the AC circuit 220. A similar graph is created based on a signal from, for example, the current sensor 306. The frequency and magnitude values ​​are omitted from the figure because they depend on various factors, such as the mains frequency of the AC circuit 220, the amplitude of the AC voltage, and the amplitude of the AC current.

[0090] Line 500 illustrates the frequency components of the signal when no arc fault occurs. The frequency components are mostly centered around a main frequency 510 of the AC circuit 220. The main frequency 510 is, for example, 50 Hz or 60 Hz. Ideally, the frequency components around the main frequency 510 are a narrow spike. However, due to various disturbances in the AC circuit 220, there is a frequency band around the main frequency 510 caused by the disturbances. When there is no arc fault, frequencies other than the main frequency 510 are present in the frequency components of the signal. As illustrated in line 500, the magnitudes of those other frequencies are much lower than the magnitude of the main frequency 510.

[0091] Line 502 illustrates the frequency content of the signal when an arc fault 250 occurs. Due to the arc fault 250, the amplitude of frequencies other than the main frequency 510 increases in the signal. As a result, the magnitude of the main frequency 510 decreases while the magnitude of the frequencies other than the frequency 510 increases. This results in the signal having a lower magnitude at the main frequency 510 when the arc fault 250 occurs compared to when the arc fault 250 does not occur. The signal has a higher magnitude at frequencies other than the main frequency 510 when the arc fault 250 occurs compared to when the arc fault 250 does not occur. Based on the change in frequency content, the on-board charger 106 can detect that an arc fault 250 has occurred. For example, the on-board charger 106 detects an arc fault 250 when the change in frequency content exceeds a threshold value.

[0092] FIG. 6 illustrates a method according to a second embodiment of the present invention. The method is for detecting an arc fault 250 using an electric vehicle 100. The electric vehicle 100 comprises an electric circuitry 102 and sensors 304, 306. The method includes the following steps: A first step is to connect the electric circuitry 102 to an external electric circuit 120 to form an AC circuit 220. A second step is to generate a signal, for example with a sensor, based on the current and / or voltage of the AC circuit 220. A third step is to transmit energy between the electric circuitry 102 and the external electric circuit 120 under the control of the signal. A fourth step is to detect an arc fault 250 in the AC circuit 220 based on the signal. A fifth step is to trip a safety mechanism of the external electric circuit 120 with the electric circuitry 102. The safety mechanism is tripped, for example, by shorting the AC circuit 220.

[0093] As required, this document describes detailed embodiments of the present invention.

[0094] Various terms used in the description should not be interpreted as limiting, but rather as a comprehensive description of the invention.

[0095] As used herein, the word "a" means one or more than one, unless otherwise specified. The phrase "plurality" means two or more than two. The words "comprise" and "have" do not exclude the presence of additional elements. [Explanation of symbols]

[0096] 100 Electric Vehicles 102 Electrical Circuit Network 104 Battery 106 On-board charger 110 Coupling device 120 External Electrical Circuit 122 Fuse box 124 Charging Station 126 AC wiring 131~134 Electric motor 210 Bonding Interface 220 AC circuit 230 DC circuit 236 DC wiring 241 phase wire 242 Neutral conductor 243 Ground wire 244 Positive DC line 245 Negative DC line 250 Arc Fault 300 Power Converter 301 First Switch 302 Second Switch 304 Voltage Sensor 306 Current Sensor 310 Computing equipment 320 Communication Equipment 330 Low-pass filter 400 time period 410 time limit 411 Disturbance 500 lines 502 line 510 Main Frequency

Claims

1. An electric vehicle (100) comprising an electrical network (102), the electrical circuitry (102) comprising a battery (104) and an on-board charger (106); the battery (104) is configured to store electrical energy; the on-board charger (106) and the battery (104) are arranged to form a DC circuit (230) for transmitting the electrical energy as DC power between the on-board charger (106) and the battery (104); the on-board charger (106) is configured to convert the electrical energy between DC power and AC power; the on-board charger (106) is configured to be coupled to an external electrical circuit (120) to form an AC circuit (220) for transmitting the electrical energy as AC power between the on-board charger (106) and the external electrical circuit (120); The electric vehicle (100), wherein the on-board charger (106) is configured to detect an arc fault (250) in the AC circuit (220).

2. The electric vehicle (100) of claim 1, wherein the on-board charger (106) is configured to detect the arc fault (250) in the external electrical circuit (120).

3. The electric vehicle (100) of claim 2, wherein the on-board charger (106) is configured to trip a safety mechanism of the external electrical circuit (120) upon detecting the arc fault (250).

4. 4. The electric vehicle (100) of claim 3, wherein the on-board charger (106) is configured to trip the safety mechanism of the external electrical circuit (120) by creating a short circuit in the AC circuit (220).

5. 5. The electric vehicle (100) of claim 3 or 4, wherein the on-board charger (106) is configured to be coupled to a ground conductor (243) of the external electrical circuit (120), and the on-board charger (106) is configured to trip the safety mechanism by providing a current and / or voltage to the ground conductor (243).

6. the on-board charger (106) comprising sensors (304, 306) configured to generate a signal based on a characteristic of the AC circuit (220); The electric vehicle (100) of claim 1, wherein the on-board charger (106) is configured to detect the arc fault (250) based on the signal.

7. 7. The electric vehicle (100) of claim 6, wherein the on-board charger (106) is configured to convert the electrical energy between DC power and AC power under control of the signals from the sensors (304, 306).

8. The electric vehicle (100) of claim 6, wherein the sensors (304, 306) include a current sensor (306) configured to generate the signal based on a current in the AC circuit (220).

9. The electric vehicle (100) of claim 6, wherein the sensors (304, 306) include a voltage sensor (304) configured to generate the signal based on a voltage of the AC circuit (220).

10. The electric vehicle (100) of claim 6, wherein the on-board charger (106) comprises a low pass filter (330) disposed in the AC circuit (220).

11. 11. The electric vehicle of claim 10, wherein the on-board charger includes a power converter configured to convert the electrical energy between DC power and AC power, and the low-pass filter is disposed upstream of the power converter and downstream of the sensor.

12. 7. The electric vehicle (100) of claim 6, wherein the on-board charger (106) comprises a computing device (310) configured to detect the arc fault (250) based on time variations of the signal and / or frequency content of the signal.

13. The electric vehicle (100) of claim 1, wherein the on-board charger (106) is configured to generate a warning signal upon detecting the arc fault (250).

14. 10. The electric vehicle of claim 1, wherein the energy in the AC power is at a first voltage and the energy in the DC power is at a second voltage, the first voltage being different from the second voltage, and the on-board charger is configured to convert the energy in the AC power at the first voltage to the energy in the DC power at the second voltage and / or vice versa.

15. The electric vehicle (100) of claim 1 , wherein the on-board charger (106) comprises a coupling device (110) configured to electrically couple the on-board charger (106) to the external electrical circuit (120).

16. 2. The electric vehicle (100) of claim 1, comprising an electric motor (131-134) configured to drive the electric vehicle (100), and the battery (104) configured to provide electrical energy to the electric motor (131-134).

17. 10. An on-board charger (106) for use with the electric vehicle (100) of claim 1, comprising: the on-board charger (106) is configured to convert electrical energy between DC power and AC power; the on-board charger (106) is configured to be coupled to an external electrical circuit (120) to form an AC circuit (220) for transmitting the electrical energy as AC power between the on-board charger (106) and the external electrical circuit (120); The on-board charger (106), wherein the on-board charger (106) is configured to detect an arc fault (250) in the AC circuit (220).

18. The on-board charger (106) of claim 17, configured to detect the arc fault (250) in the external electrical circuit (120).

19. The on-board charger (106) of claim 18, configured to trip a safety mechanism of the external electrical circuit (120) upon detecting the arc fault (250).

20. A method for detecting an arc fault (250) using an electric vehicle (100), the electric vehicle (100) comprising an electrical network (102) including a battery (104) and an on-board charger (106), and sensors (304, 306), the method comprising: - connecting said electrical network (102) to an external electrical circuit (120) to form an AC circuit (220); generating a signal in said sensor (304, 306) based on the current and / or voltage of said AC circuit (220); - detecting an arc fault (250) in said AC circuit (220) based on said signal; A method comprising:

21. - transferring energy between said electrical network (102) and said external electrical circuit (120) under the control of said signals from said sensors (304, 306); 21. The method of claim 20, comprising:

22. - tripping the safety mechanism of said external electric circuit (120) in said electric network (102); 21. The method of claim 20, comprising:

23. - short-circuiting said AC circuit (220); 23. The method of claim 22, comprising:

24. When executed by a computing device (310) of an on-board charger (106) coupled to an external electrical circuit (120) to form an AC circuit (220), the on-board charger (106) is instructed to: - generating a signal based on the current and / or voltage of said AC circuit (220); - detecting an arc fault (250) in said AC circuit (220) based on said signal; A computer program having instructions to cause a computer to perform the following:

25. The on-board charger (106) - tripping the safety mechanism of said external electric circuit (120); 25. A computer program as claimed in claim 24, which causes the computer program to:

26. detecting the arc fault (250) in the AC circuit (220) based on the signal, - detecting the variation of said signal over time, and / or - detecting the frequency content of said signal; 26. A computer program according to claim 24 or 25, comprising:

27. The on-board charger (106) - generating a warning signal upon detecting said arc fault (250); 25. A computer program as claimed in claim 24, which causes the computer program to:

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