DE102018217255A1 - Method for regulating the voltage of an energy supply system - Google Patents

Abstract

The invention relates to a method for regulating the voltage of a power supply system of a vehicle, the power supply system comprising a low voltage network (14) with at least one busbar (18) and at least one low voltage subnet (42), which has at least one voltage converter (46) with a control or regulating device (50) are electrically connected to one another, the voltage of the at least one low-voltage sub-network (42) being set to an actual output voltage (U) via the at least one control or regulating device (50) on the basis of a target output voltage (U), the Target output voltage (U) is calculated on the basis of a function of an input voltage (U) of the busbar (18).

Description

The present invention relates to a method for voltage regulation of a power supply system of a vehicle and an apparatus for performing such a method. The invention further relates to a motor vehicle which has such a device.

In motor vehicles, electrical systems in the form of multi-voltage electrical systems, in particular dual-voltage electrical systems, are becoming increasingly important. A first sub-network (low-voltage on-board network) can have a first, lower on-board network voltage (in particular 12V, 14V or 28V) and a second sub-network (high-voltage on-board network) can have a second, higher on-board network voltage (in particular 48V ) exhibit. A high-voltage on-board electrical system can have a high-performance energy store (high-voltage battery HVB), for example a 48V Li-ion battery. Such high-voltage batteries are usually assigned their own control unit (BMS battery management system). The interface between the low-voltage electrical system and the high-voltage electrical system is in particular a direct voltage converter (DC / DC converter).

State of the art

Out DE 10 2012 206 932 A1 a motor vehicle electrical system with at least two subnetworks is known. The subnetworks can be connected to one another by means of a DC voltage converter and a bypass switch.

The background of the invention is that with the introduction of electric vehicles or hybrid vehicles, a DC / DC converter is needed in the vehicle. Sometimes more than one converter is installed in the vehicle to supply the electrical consumers. There is a new topology of the energy supply system in the vehicle, which zone is called architecture. in the 48V There is an on-board electrical system 48V Battery and some 48V Consumer. All 12V Consumers are distributed in several zones and each zone is equipped with a DC / DC converter 48V Vehicle electrical system connected. This topology has a problem. If the tension in that 48V Electrical system sinks, everyone tries 48 / 12V DC / DC converter through the voltage regulation more current from the 48V To pull the vehicle electrical system in order to maintain the voltage level in the respective zone. However, this leads to a further drop in voltage in the 48V Wiring system and ultimately to a failure of the 48V Electrical system.

The object of the invention is therefore to provide a method for voltage regulation of an energy supply system, with which a failure of the vehicle electrical system can be avoided in an economical manner.

Disclosure of the invention

The object is achieved by a method for voltage regulation of an energy supply system according to claim 1. A device for carrying out the method for voltage regulation of an energy supply system is specified in claim 7. The respective dependent claims refer back to advantageous developments of the invention.

In the method according to the invention for regulating the voltage of a power supply system of a vehicle, the voltage of the at least one low-voltage sub-network is set to an actual output voltage via the at least one control or regulating device, using a target output voltage, the target output voltage being based on a function of an input voltage of the busbar is calculated.

A control or regulating device is understood to mean, for example, a control loop via which the actual output voltage can be regulated. A busbar in the sense of the present invention is a possibility of connecting a plurality of low-voltage sub-networks which have a lower voltage than the busbar.

The advantage of the invention is that the voltage for the low-voltage subnetworks should not be kept constant regardless of the voltage of the busbar. The voltage for the low-voltage subnets is thus made dependent on the voltage of the busbar, so that the voltage of the low-voltage subnetworks is adjusted accordingly in the event of a voltage drop on the busbar. In this way it can be avoided that the low-voltage subnets contribute to a further voltage drop on the busbar for regulating their voltage and this leads to a failure of the vehicle electrical system.

Since a regulation for the voltage of the low-voltage subnetworks already exists, only the regulation has to be adapted, which makes it possible to implement such a method in an economical manner.

In a preferred embodiment of the invention, a linear function is used as a function. A linear function has the advantage that the control or regulating effort is minimized and that the control or regulating device does not oscillate. However, other functions are also conceivable, in which, for example, the slope continues to increase as the voltage decreases, ie a reduction in the voltage of the low-voltage sub-networks increases.

In a further preferred embodiment of the invention, a slope for the function of ≥0 is used. This means that if the voltage on the busbar drops, the same or a lower voltage is selected for the low-voltage sub-networks. A lower voltage is preferably selected for the vast majority of the low-voltage subnetworks, so that there is no failure of the vehicle electrical system overall.

The function is preferably determined as a function of the at least one low-voltage sub-network. This means that the function is determined according to the consumers of the low-voltage network. As a result, the function can be better adapted to the low-voltage sub-network or to the consumers in the low-voltage sub-network. In this way, in the event of a large voltage fluctuation in the busbar, depending on the function of the consumers, these consumers can function adequately.

In an advantageous embodiment of the invention, all low-voltage sub-networks are regulated according to the same function. This has the advantage that the control effort can be minimized, so that such a solution can be implemented economically.

In an advantageous development, a lower slope of the function is used for at least one low-voltage sub-network in comparison to other low-voltage sub-networks. This means that at least one low-voltage sub-network has a different function than the other low-voltage sub-networks. As a result, the voltage supply can be better adapted to the respective consumer in the low-voltage subnets.

Safety-relevant components particularly preferably have a low slope. This means that the voltage for these consumers is changed only slightly or not at all when the voltage on the busbar drops. In this way, full functionality can be ensured, in particular for safety-relevant consumers, such as steering or brakes. In return, the voltage can be used for other consumers, e.g. Ventilation or heating experience a higher reduction. This means that each low-voltage subsystem can be optimally designed so that there is no failure of the on-board network.

The invention additionally includes a device for carrying out the method for voltage regulation of a power supply system of a vehicle. The device comprises a low-voltage network comprising a busbar and at least one low-voltage sub-network for energizing low-voltage sub-network consumers, the at least one low-voltage sub-network being electrically connected to the busbar, and a voltage converter with control or regulating device for setting a voltage for the low-voltage sub-network consumer , With the control or regulating device based on an input voltage of the busbar, a target output voltage of the voltage converter can be calculated via a predetermined function.

The advantages mentioned for the method can be achieved with such a device.

The invention additionally comprises a motor vehicle, which comprises the device for carrying out the method for voltage regulation of a power supply system of a vehicle. The advantages mentioned for the method can be achieved with such a motor vehicle.

• 1 Ausführungsbeispiel einer Vorrichtung zum Durchführen des erfindungsgemäßen Verfahrens zur Spannungsregelung eines Energieversorgungssystems,
• 2 Verfahren zur Spannungsregelung eines Energieversorgungssystems nach einem ersten Ausführungsbeispiel, und
• 3 Verfahren zur Spannungsregelung eines Energieversorgungssystems nach einem zweiten Ausführungsbeispiel.

Embodiments of the invention are shown in the drawing and explained in more detail in the following description. It shows:

• 1 Embodiment of a device for performing the method according to the invention for voltage regulation of an energy supply system,
• 2nd Method for voltage regulation of a power supply system according to a first embodiment, and
• 3rd Method for voltage regulation of an energy supply system according to a second embodiment.

1 shows an embodiment of a device 10th for carrying out the method according to the invention for regulating the voltage of an energy supply system. The device 10th includes a low-voltage network 14 . The low voltage network 14 includes a busbar 18th which, for example, has a voltage of 48V has a busbar consumer 22 which is on the voltage of the busbar 18th is operated, is connected. On the busbar 18th is also a busbar energy storage 26 , which is required to store and provide energy.

The busbar 18th is also with a high voltage converter 30th electrically connected, via which the low voltage is transformed to a high voltage for a high-voltage network HV. This high-voltage network HV is a high-voltage energy storage 34 connected, which is required for storing and providing the energy for the high-voltage network HV. There is an inverter on the high-voltage network HV 38 connected via which the DC voltage is converted into a three-phase AC voltage for operating an electric motor EM.

The low voltage network 14 also includes several low-voltage sub-networks 42 (Zone 1 , Zone 2nd , Zone X), which on the busbar 18th are connected. Although here only three low-voltage subnets 42 are indicated in this figure that a variety of low-voltage subnets 42 on the busbar 18th can be connected.

The low-voltage subnets 42 each have a voltage converter 46 with a control or regulating device 50 on. Via the control or regulating device 50 becomes the voltage of the busbar 18th to the voltage of the at least one low-voltage sub-network 42 , which is 12V here, for example. The voltage converter 46 converts the voltage of the busbar 18th according to the specifications of the control or regulation device 50 to the appropriate voltage. This voltage is used in every low-voltage sub-network 42 arranged low-voltage sub-network consumer 54 , such as steering, brakes, heating and / or ventilation.

In 2nd a method for voltage regulation of a power supply system according to a first embodiment of the invention is shown. In this figure it is shown that the control or regulating device 50 depending on an input voltage U _in the busbar 14 the target output voltage based on a linear function (see graph) U _out-should calculated. Based on an actual output voltage U _{out_ist} the voltage is regulated accordingly.

This will reduce the input voltage U _in the busbar 14 a smaller target output voltage U _{out_soll} for the voltage conversion step using the voltage converter 46 calculated. An actual output voltage drops accordingly U _{out_ist} . This causes the current to run out of the busbar 14 is removed when the voltage of the busbar drops 14 does not increase and failure is avoided.

3rd shows the method for voltage regulation of a power supply system according to a second embodiment of the invention. This procedure differs from the procedure in 2nd in that not all low-voltage subnets 42 (Zone 1 , Zone 2nd , Zone 3rd ) the same linear function of calculating the target output voltage U _{out_soll} exhibit. This is particularly the case in the graph in 3rd to see. The slope of the function of the various low-voltage subnets 42 (Zone 1 , Zone 2nd , Zone 3rd ) is different.

The low-voltage subnets 42 can with regard to safety-relevant low-voltage sub-network consumers 54 , such as steering and brakes, have a lower slope. In the as a zone 1 designated low-voltage subnet 42 for example, the slope is zero. This allows these low-voltage sub-network consumers 54 who are sensitive to lower voltage, the necessary voltage is provided.

For the less voltage-sensitive low-voltage sub-network consumers 54 , such as heating or fans, which here, for example, in zone 2nd or zone 3rd can be arranged, in the event of a voltage drop in the voltage on the busbar 18th a lower actual output voltage U _{out_ist} for these low-voltage subnet consumers 54 to be provided. This causes a failure of the low voltage network 14 avoided. In addition, there can be sufficient voltage for the safety-relevant low-voltage sub-network consumers 54 to be provided.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102012206932 A1 [0003]

Claims (8)

Method for regulating the voltage of a power supply system of a vehicle, the power supply system comprising a low-voltage network (14) with at least one busbar (18) and at least one low-voltage sub-network (42), which are electrically connected to one another via at least one voltage converter (46) with a control or regulating device (50) are connected, the at least one control or regulating device (50) being used to set the voltage of the at least one low-voltage sub- _network (42) to an actual output voltage (U _{out_act} ) based on a target output voltage (U _{out_soll} ), characterized in that the Target output voltage (U _{out_soll} ) is calculated on the basis of a function of an input voltage (U _in ) of the busbar (18). Procedure for voltage regulation according to Claim 1 , characterized in that a linear function is used as a function. Procedure for voltage regulation according to Claim 2 , characterized in that a slope is used for the function of ≥0. Method for voltage regulation according to one of the preceding claims, characterized in that the function is determined as a function of the at least one low-voltage sub-network (42). Method for voltage regulation according to one of the preceding claims, characterized in that all low-voltage sub-networks (42) are regulated according to the same function. Procedure for voltage regulation according to Claim 4 , characterized in that a lower slope of the function is used for at least one low-voltage sub-network (42) compared to other low-voltage sub-networks (42). Device (10) for carrying out the method for regulating the voltage of a power supply system of a vehicle, according to one of the preceding claims, the device (10) comprising: a low-voltage network (14) comprising a busbar (18) and at least one low-voltage sub-network (42) for energizing low-voltage sub-network consumers (54), the at least one low-voltage sub-network (42) being electrically connected to the busbar (18), and - a voltage converter (46) with control or regulating device (50) for setting a voltage for the low-voltage sub-network - Consumer (54), with the control or regulating _device (50) being able to calculate a target output voltage (U _{out_soll} ) of the voltage converter (46) via a predetermined function based on an input voltage (U _in ) of the busbar (18). Motor vehicle which has a device (10) Claim 7 having.

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