Search

CN-122003337-A - Method for operating a charger, energy system and motor vehicle

CN122003337ACN 122003337 ACN122003337 ACN 122003337ACN-122003337-A

Abstract

The invention relates to a method for operating a charger (1) for a motor vehicle, in particular an on-board charger for a motor vehicle, wherein the charger (1) has a multiphase input connection (3) for connection to a multiphase supply network connection (4) of a particularly stationary power supply network, and a voltage converter (5), wherein the voltage converter (5) has at least one intermediate circuit (13) with at least one intermediate circuit capacitor (14, 15). It is provided that after connection of the input connection (3) to the supply network connection (4), a first intermediate circuit voltage of the intermediate circuit (13) is detected before connection of the intermediate circuit (13) to a neutral phase (N) of the input connection (3) by means of a controllable switching element (S4) by means of a voltage sensor (V13) of the intermediate circuit (13), and a second intermediate circuit voltage of the intermediate circuit (13) is detected after connection of the intermediate circuit to the neutral phase (N) of the input connection, and that a comparison of the second intermediate circuit voltage to the first intermediate circuit voltage is used to determine whether the supply network connection (4) has a neutral phase (N) connected to the neutral phase.

Inventors

  • L. Viditz

Assignees

  • 罗伯特·博世有限公司

Dates

Publication Date
20260508
Application Date
20240920
Priority Date
20231010

Claims (10)

  1. 1. Method for operating a charger (1) for a motor vehicle, in particular an on-board charger for a motor vehicle, wherein the charger (1) has a multiphase input connection (3) for connection to a multiphase supply network connection (4) of a particularly stationary power supply network, and a voltage converter (5), wherein the voltage converter (5) has at least one intermediate circuit (13) with at least one first and second intermediate circuit capacitor (14, 15), characterized in that after connection of the input connection (3) to the supply network connection (4) a fourth voltage sensor (V13) of the intermediate circuit (13) is used, a first intermediate circuit voltage of the intermediate circuit (13) is detected before connection of the intermediate circuit (13) to a neutral line phase (N) of the input connection (3) by means of a controllable fourth switching element (S4), and a second intermediate circuit voltage of the intermediate circuit (13) is detected after connection of the intermediate circuit to the neutral line of the input connection, and that a comparison of the intermediate circuit voltage to the neutral line (4) is made.
  2. 2. Method according to claim 1, characterized in that the zero line is inferred to be present when the second intermediate circuit voltage is higher than the first intermediate circuit voltage, in particular higher than a predetermined limit value.
  3. 3. The method of claim 1, wherein the zero line is inferred to be present when the second intermediate loop voltage corresponds to an expected voltage difference between a positive peak voltage and a negative peak voltage of a phase of the input junction that is being energized.
  4. 4. Method according to any of the preceding claims, wherein a first phase (L1) of the phases has a first switching element (S1) between the input connection (3) and the voltage converter (5), a second phase (L2) of the phases has a third switching element (S3) between the input connection (3) and the voltage converter (5), wherein a pre-charge resistor (S1R, S R) is connected in parallel with respect to the first switching element (S1) and the third switching element (S3), respectively, and wherein the first and third switching elements (S1, S3) are operated for separating the respective phase (L1, L2) from the voltage converter (5) in a stationary state and for connecting at least one of the first and second phases (L1, L2) with the voltage converter (5) in a charged state.
  5. 5. Method according to claim 4, characterized in that a third phase (L3) of the phases has a second switching element (S2) between the input connection (3) and the voltage converter (5), which is operated to connect the voltage converter (5) with the first phase (L1) in the rest state and to connect the voltage converter (5) with the third phase (L3) in the charged state.
  6. 6. Method according to claim 5, characterized in that after the connection of the input connection (3) to the supply network connection (4), at least one first voltage of the first phase (L1) and at least one second voltage of the second phase (L2) are monitored, wherein an expected voltage difference is determined from the first voltage and the second voltage.
  7. 7. The method of claim 6, wherein the expected voltage difference is derived from inter-phase correlations of the first voltage and the second voltage.
  8. 8. Charger (1) for a motor vehicle, in particular an on-board charger for a motor vehicle, having a multiphase input connection (3) for connection to a multiphase supply network connection (4) of an in particular stationary power supply network, and having a voltage converter (5), wherein the voltage converter (5) has at least one intermediate circuit (13) with at least one first and second intermediate circuit capacitor (14, 15), characterized by a controller (18) which is specifically configured for carrying out the method according to any one of claims 1 to 7 when the prescribed use is met.
  9. 9. Energy system (2) for a motor vehicle, having at least one electrical energy store, characterized in that a charger (1) according to claim 8 is assigned to the energy store.
  10. 10. Motor vehicle with an energy system (2) according to claim 9.

Description

Method for operating a charger, energy system and motor vehicle Technical Field The invention relates to a method for operating a charger for a motor vehicle, in particular an on-board charger for a motor vehicle, wherein the charger has a multiphase input connection for connection to a multiphase supply network connection of a particularly stationary power supply network, and has a voltage converter, wherein the voltage converter has at least one intermediate circuit with at least one intermediate circuit capacitor. The invention further relates to a charger for a motor vehicle, in particular configured as an on-board charger for a motor vehicle, having a multiphase input connection for connection to a multiphase supply network connection of a particularly stationary power supply network, and having a voltage converter, wherein the voltage converter has an intermediate circuit with at least one intermediate circuit capacitor, and having a controller. Furthermore, the invention relates to an energy system of a motor vehicle with a charger as mentioned above and a motor vehicle with such an energy system. Background The power grid has different designs worldwide, which can be distinguished from one another by its grid voltage, grid frequency and distribution system. As motor vehicles in particular become more electrified, the need for chargers that can be connected to different power supply networks in order to be able to charge the energy store of the motor vehicle at any time also rises. A charger for charging a high-voltage battery of an electric vehicle can be coupled to one or more electrical phases of a supply network connection, for example, using a plurality of available electrical phases. Such chargers generally have, in addition to the input connection, a voltage converter which converts, for example, an ac voltage supplied by a power supply network into a dc voltage suitable for the energy store. Such chargers can be configured either as on-board chargers (as part of the energy system of the motor vehicle) or as separate chargers that are carried around by the user and can be externally coupled. It is known from the prior art to assign a voltage sensor to each phase of the input connection in order to determine the grid configuration by evaluating the detected voltage. For this purpose, a plurality of parameters for each detected voltage is generally evaluated. These parameters are, for example, the absolute voltage and the effective voltage, and/or the frequency and the phase of the voltage signal of the respective phase. The grid configuration is then derived from a comparison of the parameters respectively assigned to the phases. In the case of three-phase connection and symmetrical operation of the charger, connection of the neutral line can be omitted because the phase currents in the neutral line are offset by the symmetrical operation. However, the presence or absence of a neutral line on the supply network connection side is of great importance for the regulation concept of the charger. Although most on-board chargers for motor vehicles have a wired neutral or neutral phase, wall-mounted boxes having a three-phase coupling without a neutral are also provided. Disclosure of Invention The method according to the invention with the features of claim 1 has the advantage that the usual inherently present components of the charger can be used in an advantageous manner to detect the presence of a neutral wire. According to the invention, after the connection of the input connection to the supply network connection, a first intermediate circuit voltage of the intermediate circuit is detected, preferably in time, before the intermediate circuit is connected to a neutral line of the input connection by means of a fourth controllable switching element, and a second intermediate circuit voltage of the intermediate circuit is detected, preferably in time, after the intermediate circuit is connected to the neutral line of the input connection, and a comparison of the second intermediate circuit voltage with the first intermediate circuit voltage is used to determine whether the supply network connection has a neutral line connected to the neutral line. Depending on whether a zero line is present, different charging characteristics of the intermediate circuit or of the intermediate circuit capacitor are obtained. As soon as the charger is connected to the supply network connection via the input connection, the intermediate circuit is usually precharged, for example by means of a so-called precharge resistor, also before the actual charging process begins. From the pre-charge, there is a reliable indication as to whether the zero line has been coupled. It can thus be recognized in a simple manner whether the connected supply network connection has a neutral line connected to the neutral line. Preferably, the method comprises the step of manipulating the charger in dependence of the identification of the c