CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 of German Applications 10 2019 120 471.2, filed Jul. 30, 2019 and 10 2019 124 163.4, filed Sep. 10, 2019, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention pertains to an onboard power supply system in a vehicle, in which one or more consumers are supplied with electrical energy redundantly.

TECHNICAL BACKGROUND

In vehicles in which driving functions are performed by control systems provided in the vehicle, i.e., for example, in vehicles built for autonomous driving, it is necessary to have the ability to operate especially safety-relevant consumers, for example, a steering system, a spacing system or a lane keeping system, with a high operational reliability. For example, redundantly operating batteries are used for this purpose, so that such consumers can be supplied from two or at least two batteries. The batteries are connected to and decoupled from the consumers via circuit breaker devices. Such circuit breaker devices are also used especially to prevent damage to the consumers or to some of the consumers by decoupling the consumers or some of the consumers when defects or fault conditions, for example, overvoltage, develop.

SUMMARY

An object of the present invention is to provide an onboard power supply system for supplying at least one consumer with electrical energy in a vehicle as well as a process for operating an onboard power supply system for supplying at least one consumer with electrical energy in a vehicle, with which onboard power supply system and process it is possible to respond to the development of overvoltages in the onboard power supply system reliably and rapidly.

According to a first aspect, this object is accomplished by an onboard power supply system for supplying at least one consumer with electrical energy in a vehicle, comprising:a first battery,a second battery, anda circuit breaker device connecting the first battery and the second battery to one another in parallel to a consumer connection line area,wherein the circuit breaker device comprises:a first circuit breaker group between the first battery and the consumer connection line area, wherein the first circuit breaker group comprises a first circuit breaker and, connected in series to it, a second circuit breaker, wherein each circuit breaker of the first circuit breaker and the second circuit breaker has an input terminal and an output terminal and has a line connection between the input terminal and the output terminal in a closed state and acts in an open state as a diode blocking in the direction from the output terminal to the input terminal, wherein the output terminal of the first circuit breaker is connected to the output terminal of the second circuit breaker and wherein the input terminal of the first circuit breaker is connected to the first battery and the input terminal of the second circuit breaker is connected to the consumer connection line area, anda second circuit breaker group between the second battery and the consumer connection line area, wherein the second circuit breaker group comprises a third circuit breaker and, connected in series to it, a fourth circuit breaker, wherein each circuit breaker of the third circuit breaker and the fourth circuit breaker has an input terminal and an output terminal and has a line connection between the input terminal and the output terminal in the closed state and acts as a diode blocking in the direction from the output terminal to the input terminal in an open state, wherein the output terminal of the third circuit breaker is connected to the output terminal of the fourth circuit breaker and wherein the input terminal of the third circuit breaker is connected to the second battery and the input terminal of the fourth circuit breaker is connected to the consumer connection line area,

wherein the onboard power supply system further comprises:a first voltage detection device for detecting the voltage level in a line area between the input terminal of the first circuit breaker and the first battery,a second voltage detection device for detecting the voltage level in a line area between the input terminal of the third circuit breaker and the second battery,a third voltage detection device for detecting the voltage level in the area of the consumer connection line area, andan overvoltage detection device for detecting an overvoltage in the area of the consumer connection line area on the basis of the voltage level detected by the third voltage detection device and for switching the first circuit breaker and the third circuit breaker into their respective open states when overvoltage is detected in the area of the consumer connection line area.

An overvoltage state is detected in the onboard power supply system configured according to the present invention by the voltage level being monitored in the line area connecting the different electrical energy consumers, especially also the safety-relevant electrical energy consumers, namely, in the consumer connection line area, and by responding by opening the circuit breakers of the two circuit breaker groups, which circuit breakers are connected to the batteries, when an overvoltage state is detected or recognized. The opening of these two circuit breakers when the second and fourth circuit breakers are still being held in the closed state does not at first decouple the consumers from the batteries, because the first circuit breaker and the third circuit breaker still continue to allow a flow of current from the batteries in the direction of the consumer connection line area based on their diode function. However, the two batteries or the line areas located between the batteries and the respective circuit breakers connected thereto are decoupled by this diode function, so that in each of these line areas, the voltage level present there can be checked for the presence of a defect, especially an overvoltage state, unaffected by the voltage level prevailing in the respective other line area. The line area that then shows an overvoltage when comparing the voltage level prevailing there with a reference voltage level can then be decoupled from the consumer connection line area by opening the associated second or fourth circuit breaker, so that this consumer connection line area or the consumer connected thereto can continue to be supplied via the battery operating correctly and without overvoltage.

In order to make it possible to carry out the operation of detecting an overvoltage in the consumer connection line area as rapidly as possible, it is proposed that the overvoltage detection device be configured as an electrical circuit for comparing the voltage level detected by the third voltage detection device with a first reference voltage level and for generating a circuit breaker switching signal switching the first circuit breaker and the third circuit breaker into their open states when the voltage level in the consumer connection line area is above the first reference voltage level. The configuration of the overvoltage detection device as an electrical circuit, i.e., as a circuit configured exclusively as hardware and operating without any control programs, which compares voltage levels to one another and generates switching signals in response to the comparison, leads to a very rapid response, which takes place more rapidly by several orders of magnitude compared to the generation of such switching signals in a microprocessor device programmed with control programs.

In order to make it possible to open and close the circuit breakers of the circuit breaker device for the normal switching operation of the circuit breaker device, a circuit breaker actuating unit may be provided, wherein the circuit breaker actuating unit is configured to switch each of the circuit breakers between its open state and its closed state, and wherein the circuit breaker actuating unit is configured to compare the voltage level detected by the first voltage detection device and the voltage level detected by the second voltage detection device with a second reference voltage level.

Such a circuit breaker actuating unit may comprise a microprocessor device generating switching commands for the circuit breakers. The switching commands for the circuit breaker device can thus be generated in the microprocessor device on the basis of control programs stored in this microprocessor device.

In order to make it possible to take the necessary actions for checking the voltage level in the area of the two batteries by means of the circuit breaker actuating unit when an overvoltage develops in the consumer connection line area, it is proposed that the overvoltage detection device be configured to output an overvoltage signal to the circuit breaker actuating unit when overvoltage is detected in the consumer connection line area, wherein the circuit breaker actuating unit is configured to compare the voltage level detected by the first voltage detection device and the voltage level detected by the second voltage detection device with the second reference voltage level when the overvoltage signal is received, and to switch the second circuit breaker into its open state when the voltage level detected by the first voltage detection device is above the second reference voltage level, and to switch the fourth circuit breaker into its open state when the voltage level detected by the second voltage detection device is above the second reference voltage level.

In order to ensure now the voltage supply via the respective, correctly operating circuit breaker group, the circuit breaker actuating unit may be configured to switch the third circuit breaker into its closed state when the second circuit breaker is switched into its open state, and to switch the first circuit breaker into its closed state when the fourth circuit breaker is switched into its open state.

In the onboard power supply system according to the present invention, each circuit breaker may comprise at least one MOSFET switch, wherein the input terminal is provided in each circuit breaker by the source terminal of the at least one MOSFET switch and the output terminal is provided by the drain terminal of the at least one MOSFET switch.

According to another aspect, the object described in the introduction is accomplished by a process for operating an onboard power supply system for supplying at least one consumer with electrical energy in a vehicle, the onboard power supply system comprising:a first battery,a second battery,a circuit breaker device connecting the first battery and the second battery in parallel to one another to a consumer connection line area,

wherein the circuit breaker device comprises:a first circuit breaker group between the first battery and the consumer connection line area, wherein the first circuit breaker group comprises a first circuit breaker and, connected in series to it, a second circuit breaker, wherein each circuit breaker of the first circuit breaker and the second circuit breaker has an input terminal and an output terminal and has a line connection between the input terminal and the output terminal in a closed state and acts as a diode blocking in the direction from the output terminal to the input terminal in an open state, wherein the output terminal of the first circuit breaker is connected to the output terminal of the second circuit breaker and wherein the input terminal of the first circuit breaker is connected to the first battery and the input terminal of the second circuit breaker is connected to the consumer connection line area,a second circuit breaker group between the second battery and the consumer connection line area, wherein the second circuit breaker group comprises a third circuit breaker and, connected in series to it, a fourth circuit breaker, wherein each circuit breaker of the third circuit breaker and the fourth circuit breaker has an input terminal and an output terminal and has a line connection between the input terminal and the output terminal in a closed state and acts as a diode blocking in the direction from the output terminal to the input terminal in an open state, wherein the output terminal of the third circuit breaker is connected to the output terminal of the fourth circuit breaker, and wherein the input terminal of the third circuit breaker is connected to the second battery and the input terminal of the fourth circuit breaker is connected to the consumer connection line area,

wherein the onboard power supply system further comprises:a first voltage detection device for detecting the voltage level in a line area between the input terminal of the first circuit breaker and the first battery,a second voltage detection device for detecting the voltage level in a line area between the input terminal of the second circuit breaker and the second battery, anda third voltage detection device for detecting the voltage level in the area of the consumer connection line area, especially of an onboard power supply system in accordance with one of the above claims, comprising the steps:a) Comparison of the voltage level detected by the third voltage detection device with a first reference voltage level andb) then, if the voltage level detected by the third voltage detection device is above the first reference voltage level, switching of the first circuit breaker and of the third circuit breaker into their open states.

In order to make it possible, after detecting that an overvoltage is present in the area of the consumer connection line area, to determine in which area and especially in connection with which of the batteries such an overvoltage state has developed, provisions may furthermore be made for comparing the voltage level detected by the first voltage detection device and the voltage level detected by the second voltage detection device, after switching the first circuit breaker and the third circuit breaker into their open states in step c), with a second reference voltage level, and for then switching the second circuit breaker into its open state in a step d) when the voltage level detected by the first voltage detection device is above the second reference voltage level, and for then switching the fourth circuit breaker into its open state when the voltage level detected by the second voltage detection device is above the second reference voltage level.

Further, the third circuit breaker can then be switched in step d) into its closed state when the second circuit breaker is witched into its open state and then, when the fourth circuit breaker is switched into its open state, the first circuit breaker can be switched into its closed state.

The second reference voltage level may correspond here to the first reference voltage level.

In order to make it possible to carry out especially the first detection of an overvoltage state in the consumer connection line area without a substantial time delay and to be able then to open the circuit breakers connected to the batteries in response thereto, it is proposed that steps a) and b) be carried out by an overvoltage detection device configured as an electrical circuit. The subsequent steps, namely the checking of the line areas between the batteries and the circuit breakers connected to these and the decisions to be made in response to this checking, i.e., steps c) and d), can then be carried out by a circuit breaker actuating unit comprising a microprocessor device.

The present invention will be described below in detail with reference to the attached FIGURE. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.

