Device for determining electrical power

Abstract

A device for determining an electrical power, comprising an electrical filter (3), a measuring means (4) and a protective conductor input, wherein the filter (3) comprises a first filter input and a first filter output, wherein the measuring means (4) comprises a first and a second measuring means input, wherein the first filter output is electrically connected to the first measuring means input and the protective conductor input is electrically connected to the second measuring means input via a protective conductor (7), wherein the filter (3) is designed to receive a first electrical signal via the first filter input, to filter the first signal and to output the filtered first signal via the first filter output to the first measuring means input, characterized in that the measuring means (4) is designed to measure an electrical current through the protective conductor (7), wherein the measuring means (4) is designed toto determine an electrical power transmitted to the device using the filtered first signal received via the first measuring device input and the measured electrical current through the protective conductor (7).

Description

[0001] The present invention relates to a device for determining an electrical power according to the preamble of claim 1.

[0002] From US 2014 / 0052394 A1, a method for determining the power consumption of a server is known, in which the transmitted power is determined behind an EMI filter.

[0003] DE 10 2015 101 283 A1 discloses a method for electrically charging a high-voltage battery from an AC grid. The high-voltage battery is connected to the AC grid by means of a charger comprising several voltage rails. A filter capacitor is assigned to each voltage rail. The maximum possible charging power of the AC grid is calculated. At least one voltage rail that is dispensable for the calculated charging power is selected. The filter capacitors assigned to the dispensable voltage rails are switched off.

[0004] In contrast, the present invention is based on the object of increasing the accuracy of the measurement of a power transmitted to the filter.

[0005] This object is achieved by a device according to claim 1, a motor vehicle according to claim 8, and a method according to claim 9. Embodiments of the invention are specified in the dependent claims.

[0006] The device comprises an electrical filter, a measuring device, and a protective conductor input. The filter comprises a first filter input and a first filter output. The measuring device comprises a first and a second measuring device input. The first filter output is electrically connected to the first measuring device input. The protective conductor input is electrically connected to the second measuring device input, for example, directly via a protective conductor. In the context of this description, a direct electrical connection is understood in particular to mean that, apart from electrical conductors, no further components are connected between the two connected components.In the context of this description, a protective conductor is understood in particular to mean an electrical conductor that is designed to be at earth potential during power transmission and to electrically ground components of the device that could possibly be touched by a living being. The protective conductor can, for example, comprise multiple components. It is also possible for parts of the body of a motor vehicle, of which the device is a component, to belong to the protective conductor. The protective conductor input can, for example, be designed to be connected to a protective conductor of a charging station when the device is used to transmit electrical power from the charging station via the filter to an energy storage device.

[0007] The filter is configured to receive a first electrical signal via the first filter input, filter the first signal, and output the filtered first signal to the first measuring device input via the first filter output. The measuring device is configured to measure an electrical current through the protective conductor. Furthermore, the measuring device is configured to determine an electrical power transmitted to the filter using the filtered first signal received via the first measuring device input and the measured electrical current through the protective conductor.

[0008] This takes into account any leakage currents through the protective conductor, and the electrical power transferred to the filter can be determined particularly accurately. This is particularly advantageous when the device is used to measure the electrical power delivered from a charging station to an energy storage device, for example a motor vehicle, during a charging process. In this case, particularly accurate determination is desirable so that the energy delivered can be financially billed as accurately as possible between the operator of the charging station and the owner of the energy storage device. There are also regulations, certifications, and standards that commercially used charging stations must meet, depending on the country. One example of this is the MID certification (“Measuring Instruments Device”), which is easier to meet when using the device according to the invention than with the prior art.

[0009] The measuring device can, for example, be designed to determine the energy transmitted to the device using a calculation model adapted to a system. The device can be a component of the system. The system can, for example, comprise the electrical components of a motor vehicle.

[0010] According to one embodiment of the invention, the filter can be designed as a mains filter. In the context of this description, a mains filter is understood in particular to mean a filter that filters out interference from the power grid in order to reduce the likelihood of interference occurring in components of the device and any other components present.

[0011] According to one embodiment of the invention, the filter can be designed to attenuate asymmetric electrical currents. This is particularly advantageous for attenuating interference occurring in the power grid. If the filter has multiple filter inputs and outputs, the filter can alternatively or additionally be designed to attenuate common-mode currents occurring at the filter inputs in the same direction. This is also advantageous for attenuating interference occurring in the power grid.

[0012] According to one embodiment of the invention, the second measuring device input can be connected to additional electrical components via the protective conductor. This is particularly advantageous so that leakage currents occurring at these additional components can also be used to determine the transmitted electrical power.

[0013] According to one embodiment of the invention, the filter can comprise a second filter input and a second filter output. The measuring device can comprise a third measuring device input. The second filter output can be electrically connected to the third measuring device input, in particular directly. The filter can be designed to receive a second electrical signal via the second filter input, filter the second signal, and output the filtered second signal to the third measuring device input via the second filter output. The measuring device can be designed to determine the electrical power transmitted to the device using the filtered second signal received via the third measuring device input.

[0014] According to one embodiment of the invention, the filter can comprise a third filter input and a third filter output. The measuring device can comprise a fourth measuring device input. The third filter output can be electrically connected to the fourth measuring device input, in particular directly. The filter can be designed to receive a third electrical signal via the third filter input, filter the third signal, and output the filtered third signal to the fourth measuring device input via the third filter output. The measuring device can be designed to determine the electrical power transmitted to the filter using the filtered third signal received via the fourth measuring device input.

[0015] According to one embodiment of the invention, the filter can comprise a neutral conductor input and a neutral conductor output. The measuring device can comprise a fifth measuring device input. The neutral conductor output can be electrically connected, for example, via a neutral conductor, to the fifth measuring device input.

[0016] The motor vehicle according to claim 8 comprises a device according to one embodiment of the invention, an energy storage device and an electric drive. The energy storage device is designed to provide electrical energy to the drive. The drive is designed to drive the motor vehicle using the electrical energy. The energy storage device can also be charged by means of an electrical current flowing through the filter and the measuring device. In this case, it is particularly possible for the current to be first filtered during a charging process of the energy storage device and only then to be fed to the measuring device as filtered current. In the method according to claim 9 for determining an energy delivered to the energy storage device of the motor vehicle according to one embodiment of the invention during a charging process, the delivered energy is calculated from the power transmitted to the filter, as determined by the measuring device.

[0017] Further features and advantages of the present invention will become clear from the following description of a preferred embodiment with reference to the accompanying drawing. The same reference numerals are used for identical or similar features and for features with identical or similar functions. Fig. 1 a schematic view of a motor vehicle with a device according to an embodiment of the invention, which is connected to a charging station.

[0018] The motor vehicle 1 comprises a traction battery 5 and an electric drive 6. During operation, the drive 6 drives the motor vehicle and is supplied with electrical energy by the traction battery 5. In Fig.1, the motor vehicle 1 is electrically connected to a charging station 2. In this state, the charging station 2 charges the traction battery 5. For this purpose, the charging station 2 is connected to a filter 3 of the motor vehicle via three phase conductors L1, L2, and L3 and a neutral conductor N. The electrical energy is transmitted from the charging station 2 to the motor vehicle 1 via these conductors. The filter 3 filters the electrical signals received via the phase conductors L1, L2, and L3 and outputs filtered signals to the measuring device 4.

[0019] In addition, the charging station 2 is connected to the measuring device 4, the filter 3, and other electrical components via a protective conductor 7. The protective conductor 7 serves to ground the respective component to increase user safety. It should be noted that the protective conductor 7 can encompass various components. For example, the vehicle body can also be part of the protective conductor 7.

[0020] The measuring device 4 is designed to determine the currents occurring in the protective conductor 7. From these currents and the filtered signals, the measuring device 4 determines the power delivered by the charging station to the filter 3. This can be done, for example, using a computer-implemented model adapted to the electrical components of the motor vehicle 1.

Claims

[1] A device for determining an electrical power, comprising an electrical filter (3), a measuring means (4) and a protective conductor input, wherein the filter (3) comprises a first filter input and a first filter output, wherein the measuring means (4) comprises a first and a second measuring means input, wherein the first filter output is electrically connected to the first measuring means input and the protective conductor input is electrically connected to the second measuring means input via a protective conductor (7), wherein the filter (3) is designed to receive a first electrical signal via the first filter input, to filter the first signal and to output the filtered first signal via the first filter output to the first measuring means input, characterized byin that the measuring means (4) is designed to measure an electrical current through the protective conductor (7), wherein the measuring means (4) is designed to determine an electrical power transmitted to the device using the filtered first signal received via the first measuring means input and the measured electrical current through the protective conductor (7). [2] Device according to claim 1, characterized by that the filter (3) is designed as a mains filter. [3] Device according to one of the preceding claims, characterized by that the filter (3) is designed to dampen asymmetric electrical currents. [4] Device according to one of the preceding claims, characterized by that the second measuring device input is connected to other electrical components via the protective conductor (7). [5] Device according to one of the preceding claims, characterized byin that the filter (3) comprises a second filter input and a second filter output, wherein the measuring means (4) comprises a third measuring means input, wherein the second filter output is electrically connected to the third measuring means input, wherein the filter (3) is designed to receive a second electrical signal via the second filter input, to filter the second signal and to output the filtered second signal via the second filter output to the third measuring means input, wherein the measuring means (4) is designed to determine the electrical power transmitted to the device using the filtered second signal received via the third measuring means input. [6] Device according to the preceding claim, characterized byin that the filter (3) comprises a third filter input and a third filter output, wherein the measuring means (4) comprises a fourth measuring means input, wherein the third filter output is electrically connected to the fourth measuring means input, wherein the filter (3) is designed to receive a third electrical signal via the third filter input, to filter the third signal and to output the filtered third signal via the third filter output to the fourth measuring means input, wherein the measuring means (4) is designed to determine the electrical power transmitted to the device using the filtered third signal received via the fourth measuring means input. [7] Device according to one of the preceding claims, characterized bythat the filter (3) comprises a neutral conductor input and a neutral conductor output, wherein the measuring means (4) comprises a fifth measuring means input, wherein the neutral conductor output is electrically connected to the fifth measuring means input. [8] Motor vehicle (1), comprising a device according to one of the preceding claims, an energy store (5) and an electric drive (6), wherein the energy store (5) is designed to provide electrical energy to the drive (6), wherein the drive (6) is designed to drive the motor vehicle (1) using the electrical energy, and wherein the energy store (5) is chargeable by means of an electrical current flowing through the filter (3) and the measuring means (4). [9] Method for determining an energy delivered to the energy storage device of the motor vehicle (1) according to the preceding claim during a charging process, wherein the delivered energy is calculated from the power transmitted to the device as determined by the measuring means (4).

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