DE102010026772A1 - Electrical supply circuit for vehicle, has control circuits that control down converters respectively so that consumer voltages produced by down converters are supplied to consumers during emergency mode - Google Patents

Abstract

The circuit has an accumulator for producing accumulator supply voltage, and an upward transducer (11) for producing intermediate voltage from accumulator supply voltage. The down converters (21,22) are provided for supplying consumer voltages (UA2,UA3) produced from intermediate voltages to consumers (V2,V3) such as retention mechanism and door lock mechanism of vehicle respectively. The control circuits (25,26) control the down converters respectively so that consumer voltages are supplied to consumers during emergency mode. An independent claim is included for method for operating electrical supply circuit of vehicle.

Description

The application relates to an emergency energy supply for a vehicle. Vehicles with internal combustion engines usually have a lead-acid battery which is charged while driving and supplies the consumers of the vehicle with electrical energy. In the following, the term battery is used synonymously with the term accumulator.

The fact that now many different consumers are integrated in a vehicle, the consumption of electrical power in the vehicle increases. To continue providing a secure power supply, the US Pat. No. 7,236,893 B1 subdividing electricity consumers into safety-critical and less safety-critical ones and making it possible to switch off the less safety-critical consumers.

Nevertheless, it is still critical to provide consumers with a supply voltage while starting the engine, as the battery voltage drops sharply.

The object is therefore to provide an emergency energy supply for a vehicle that provides sufficient energy for safety-critical consumers even in critical situations, especially in accidents.

This object is solved by the subject matter of the independent claim. Advantageous embodiments will become apparent from the dependent claims.

According to the application, a supply circuit for the electrical supply of a vehicle is provided. A battery is used to generate a battery supply voltage. The supply circuit also has a first power supply unit for generating a first load voltage for supplying a first load. A second power supply unit is provided for generating a second load voltage for supplying a second load. A control circuit serves to control the first power supply unit and the second power supply unit.

The control circuit is designed such that in an emergency mode of the vehicle, the second load is supplied by the first load voltage and the second load voltage and the first power supply unit generates the first load voltage and the second power supply unit generates the second load voltage.

The supply circuit enables the individual consumers to be supplied with electrical energy in each case with the aid of the individual energy supply units. This allows individual consumers to be deactivated individually depending on the mode, if they are not necessary for the current driving situation and there is currently little energy available.

With the emergency mode, the energy supply units can be bundled and the first consumer can be supplied with the aid of the first and the second energy supply unit. This emergency mode is particularly suitable, for example, when a door opening system must be safely supplied in an emergency, especially after an accident, so that the door opens.

Also particularly suitable is the supply circuit for restraint systems, which must work safely in an emergency mode, which usually precedes an accident. Restraint systems serve to keep vehicle occupants in their seat. Belong to u. a. Belt tensioners and airbags.

In one embodiment, the first consumer is powered by no power supply and thus deactivated. This ensures that as much energy as possible is available for those applications that are absolutely necessary in an emergency. These are in particular the above-mentioned door opening system and the restraint systems.

The buffer has the advantage that energy which is obtained, for example, during the recuperation of a vehicle is stored in the buffer. The up-converter and down-converter configuration allows the latch to be charged to a higher voltage than the battery voltage. This makes it possible to store as much electrical energy as possible in the buffer.

Thus, for example, during the starting process of the engine, consumers who would normally be supplied with insufficiently high battery voltage can be powered by the energy from the latch through the buck converters.

The supply circuit can stabilize the supply voltage without adversely affecting the starting process and without reducing the current drawn from the battery as stored energy is used. Decentralized power supplies have also been proposed, in which local, distributed in the vehicle, DC chopper respectively supply individual consumers with electrical energy. It has turned out that a decentralized Voltage supply may cause that when starting the decentralized DC power controller request extra power for their consumers. Thus, the already lowered by the starting process battery voltage drops in addition, since then energy flows to the individual consumers. Decentralized controls can thus tend to increase voltage drops especially when starting the engine.

In one embodiment, a first switch is provided for connecting a supply node of the first load voltage to a supply node of the battery voltage and a second switch for connecting a supply node of the second load voltage to a supply node of the battery voltage. Thus, one or more consumers can be supplied directly from the battery in selected operating modes. There will be small losses compared to the supply from the step-down converter. Thus, in certain operating modes, consumers may be powered directly by the battery, while in other modes of operation consumers may be powered by the buck converters.

In a further embodiment, a further switch is provided for connecting a supply node of the first load voltage to a supply node of the second load voltage. By connecting this switch, the first buck converter and the second buck converter can be connected in parallel so that, for example, a load is supplied by the two buck converters. This increases the power that can be provided to this consumer.

The control circuit may comprise a higher-level controller and two lower-level controllers, wherein a first lower-level controller drives the first down-converter and the second lower-level controller drives the second down converter. The higher-level controller controls the first subordinate controller and the second subordinate controller.

With such a configuration of superordinate control and subordinate controls, a large amount of information can be processed. Information, for example about the status of the battery, the anticipated loads of the supply networks and similar information, can be evaluated in the higher-level controller. The higher-level control then decides which down-converters are switched off and which other switches are switched through. The higher-level controller controls the subordinate controls accordingly. The subordinate controls are then only concerned with the task of controlling one of the downconverters. This has advantages over a fully centralized solution where only one centralized controller needs to drive all the downconverters. Such a central controller could not sufficiently prioritize the tasks, so that there would not be enough computation time to control the downconverters.

By another switch for connecting a supply node of the battery voltage to a supply node of the intermediate voltage of the memory can be powered directly from the battery. This is advantageous for example in quiet modes of the vehicle, if it is foreseeable that in the next few weeks the vehicle will not be used. In this case, the buffer can be powered directly from the battery. If the buffer contains capacitors, they can thus be kept at a voltage level which avoids accelerated aging of the capacitors.

If a housing is provided for receiving the supply circuit and the housing has a connection for external buffer, the buffer may be partially provided in the housing and partly outside the housing. This results in an upgradable supply circuit. If larger intermediate storage for the intermediate voltage is required for larger vehicles or for a larger number of consumers in the vehicle, the buffer outside of the housing in addition to the buffer in the housing can be connected in parallel. The housing with the supply circuit therein can thus be used for both small and large vehicles.

With a measuring circuit for measuring the first load voltage and the second load voltage can be checked whether the first buck converter and the second buck converter are functional and whether the consumers are supplied with the desired voltage levels.

The supply circuit may also include a third buck converter for generating a third load voltage for supplying a third load from the intermediate voltage, wherein the voltage level of the third load voltage is adjustable independently of the first load voltage and independent of the second load voltage. This makes it possible to supply individual consumers with a variable voltage level. This may be useful for a consumer to reduce their power consumption.

The invention also relates to a vehicle with a supply circuit. Preferably, the supply circuit is provided at a relatively cool location in the vehicle, for example in the vicinity of the wheel house. It should be noted, however, that the supply circuit is protected against splashing water. In the engine compartment, however, it is comparatively warm, especially the use of supercaps as a buffer would be problematic because supercaps are usually sensitive to temperature.

The application also describes a method of operating the power supply circuit in which there is an operating mode in which the first load is supplied by the first load voltage and at the same time the second load voltage. The first buck converter generates the first load voltage and the second buck converter generates the second load voltage. Thus, buck converters can be bundled and the first load supplied by the first and second buck converters. This second mode of operation is particularly suitable, for example, when a door lock mechanism in an emergency, for example, after an accident, must be safely supplied to open the door.

The presented power supply should enable an electrical power supply that can meet the following requirements. With the aid of a high-speed CAN interface, information about starting, about power requirements, the activity of an automatic start-stop system and the status of the engine can be transmitted. A non-volatile memory is used to calibrate the power supply circuit and to store code for fault detection and diagnosis of the power supply circuit. Error messages can be displayed to the driver via a display or via instruments in the dashboard. Consumers are prioritized in the form of intelligent power management and consumers are selected based on the current power consumption battery status, a priority list, and the status of the running engine.

There are essentially three output stage modes that characterize a consumer's supply. In the first mode, the consumer is decoupled, i. H. it is powered by no power supply. In the so-called bridged state it is powered by the battery and in the stabilized state it is powered by one of the buck converters.

The cached energy is stored at a higher voltage level by means of internal or external capacitors. The energy is charged especially in case of recuperation during braking or overrun. It may also be considered to use lithium-ion batteries as external storage to use intelligent charging methods with them.

It is also possible to charge the capacitors via an external power source.

Discrete output stages are used, i. H. each output stage has a maximum level of performance. It is possible to cascade the stages so that higher performance requirements can be met for common power requests.

Different output voltage levels can be programmed. In addition, different maximum output currents can be programmed. The circuits can partially take over the function of electrical fuses. The internal diagnostic and control elements can be tested with the aid of an operating tool. The integration of the power supply should be ensured for all vehicles by the supply circuit is protected against ingress of water. The housing is optimized so that the supply circuit is cooled as well as possible.

Thus, an intelligent DC / DC converter for integration into the energy management is provided. Special applications are Stop / Start vehicles, which have particularly high demands on the state of charge of the battery. Components that are particularly susceptible to voltage dips are supported by the converter directly from the battery or by additional energy previously stored in integrated memories. Decisions for energy use and provision are made depending on the learned on-board network status.

The converter is expandable by the ability to provide additional external energy storage to the already integrated via a line connection. The converter is to provide a maximum base power of 500 W over a defined period of time.

In one embodiment, the converter is directly connected to the vehicle's HS-CAN bus for direct communication with the BCM (Body Control Module) / ECM (Engine Control Module). It decides on the distribution of the necessary and the available energy by reading battery characteristics from the intelligent battery sensor (State of Function (SOF), State of charge (SOC), battery voltage level, etc.), from BCM ( Battery brake signal bit, ignition on, consumer power requirement, emergency power request) or from the ECM (engine speed, engine running, crank request, autostart bit). For safety functions, the accident detection signal and a battery-disconnected function (battery-destroyed function) should also be taken into account by the DC / DC converter. In addition, the starting signal, which is provided via the CAN bus or via its own cable, is taken into account.

• – das Signal SOC (State of Charge) des Kondensators als Maß, wieweit der Zwischenspeicher geladen ist, und
• – das Signal Kondensatortemperatur

In addition, the converter still receives the following information from the memory unit via the HS-CAN bus:

• - The signal SOC (State of charge) of the capacitor as a measure of how much the latch is loaded, and
• - the signal capacitor temperature

• – Reduzierung der aus fossilen Brennstoffen zu erzeugenden elektrischen Energie durch Speichern von kinetischer Energie in zusätzlichen Speicherelementen, z. B. Ultracaps oder LIIO-Batterien, während des Bremsvorgangs mit hohem Ladestrom oder bei Verzögerungen mit geringem Ladestrom;
• – Vermeidung von Lastrückwirkungen, wie sie bei Standard-DC/DC Wandlern bei höheren Leistungen ab ca. 500 W auftreten;
• – Entlastung und Unterstützung des Startvorgangs durch Lastentkopplung und direkte Unterstützung aus verwendeten Speicherelementen auf höherem Spannungsniveau;
• – Im Wandler gespeicherte Prioritätslisten und Sicherheitsfunktionen helfen Fehlfunktionen von Steuergeräten und Komponenten zu vermeiden;
• – Positiver Einfluss auf die CO2 Reduzierung

This results in the following embodiments:

• Reduction of electric energy to be generated from fossil fuels by storing kinetic energy in additional storage elements, e.g. B. Ultracaps or LIIO batteries, during the braking process with high charging current or delays with low charging current;
• - Prevention of load feedback, as occurs with standard DC / DC converters at higher power from about 500 W;
• - Relief and support of the startup process by load decoupling and direct support from used memory elements at a higher voltage level;
• - Priority lists and safety features stored in the converter help to prevent malfunction of ECUs and components;
• - Positive influence on CO2 reduction

The new converter stores additional energy from existing kinetic reserves and at the same time manages the energy control to the consumers.

If, during an automatic start, the starting process takes less than 5 seconds, and thus supplies consumers from the buffer for a time of less than 5 s, it is assumed that the starting process was successful. The converter automatically detects whether a manual start or an automatic start is performed and acts accordingly in the supply control, without signaling the customer a malfunction. If the loads have been supplied from the buffer for 5 seconds, it is assumed that the vehicle is malfunctioning and the supply circuit switches all loads to the bypassed state. This means that all consumers are again supplied directly from the battery voltage.

In one embodiment of the solution is an expandable unit that can be upgraded like a block by providing external energy storage. As a result, the variants can be expanded from a basic version to a more powerful high-performance version. The electronic management of the supply eliminates the need for backups that would be necessary in a passive solution. At the same time a direct diagnosis of the supply paths, z. B. at quiescent current, short circuit or line break possible.

Thus, an intelligent DC / DC emergency power supply is provided. A particular field of application is energy management of safety-relevant components whose functionality would be limited or not available in the event of a voltage dip or during the elimination of the standard voltage supply. These may be, for example, door opening systems and restraint systems.

Decisions for the type of supply are determined from the operating state of the vehicle electrical system. The converter power depends on the predicted maximum energy requirement.

The converter is connected directly or via gateway to the HS-CAN of the vehicle for direct communication with the BCM. He decides on the distribution of the necessary and available energy by reading the battery characteristics, which are read by an intelligent battery sensor, in particular via the signals State of Function, State of Charge, Voltage Level etc .. In addition, he reads data, which he Auxiliary energy storage can be provided by a corresponding sensor, a.

In addition, the converter uses electrical energy from the recuperation to z. B. without being able to provide energy to the battery network.

To accommodate power management and deployment, the converter uses signals from both the BCM (Octopus signal flag, Ignition "On", Emergency Power Locks) and the ECM (Enginge Control Unit). namely the signals Engine Speed, Engine Running, Crank Request, etc.).

In addition, the converter detects deviating voltage values from the normal vehicle network, such as As torn battery terminals, voltage dips, battery destruction etc.

• – eine rückwirkungsfreie Energieversorgung, wie sie bei Standard-DC/DC-Wandlern ab ca. 500 W auftreten würden;
• – die Verwendung kinetischer Energie zum Speichern von elektrischer Energie in zusätzlichen Speicherelementen auf höherem Spannungsniveau, z. B. in Ultracaps und LIIO-Batterien, z. B. während des Bremsvorgangs, bei dem typischerweise ein hoher Ladestrom auftritt und/oder bei Verzögerungen, bei denen typischerweise niedrigere Ladeströme erzeugt werden.

Special advantages of the presented supply circuit are:

• - A non-reactive power supply, as would occur with standard DC / DC converters from about 500 W;
• The use of kinetic energy to store electrical energy in additional storage elements at a higher voltage level, e.g. B. in Ultracaps and LIIO batteries, z. During braking, where typically a high charging current occurs and / or at delays where typically lower charging currents are generated.

The subject of the application will now be explained with reference to an embodiment shown in the figure. It shows

1 a circuit arrangement for the power supply of a vehicle.

1 shows a circuit arrangement 10 for the power supply of a vehicle. The circuit arrangement is a power supply circuit and has the function of a smart DC-DC converter (DC / DC converter). The circuit arrangement 10 receives at its input terminals VBAT and GND the voltage supply, in this case in the amount of 12 V, that of a lead-acid battery 1 provided. The circuit arrangement 10 has a boost converter 11 on, a transformer 110 , a switch 111 and a diode 112 contains.

The transformer 110 contains two coils wound over a common core. A first coil is between the terminal VBAT and a first terminal of the switch 111 provided, the second terminal is connected to the ground. The second coil is between terminal VBAT and the anode of the diode 112 intended. The cathode of the diode 112 is with the first plates of parallel connected capacitors 14 connected while the second plates of the capacitors 14 each connected to the ground. The first plates of the capacitors 14 are also equipped with a first input of the switching unit 12 whose second input is connected to the terminal VBAT. The first plates of the capacitors are also connected to an input EXT_S of the switching arrangement 10 connected to the external capacitors, that is, capacitors outside of a housing containing the circuitry 10 includes, parallel to the capacitors 14 can be provided. The capacitors 14 and any existing external capacitors form a buffer. The voltage across the capacitors 14 is applied, is also referred to as intermediate voltage.

The output of the switching unit 12 is with a first connection of a filter 13 connected, which consists of two capacitors and a coil. Between input and output of the filter 13 the coil is provided while a first capacitor between the input and the ground and the other capacitor between the output of the filter 13 and the mass are provided. The output of the filter 13 is with inputs from five buck converters 20 . 21 . 22 . 23 and 29 connected.

Each of the down converters 20 . 21 . 22 . 23 and 29 includes an input E, a switching input S and an output A. In addition, each of the downconverters includes a switch Sc, a diode D, a coil L and a capacitor C. The switch Sc is connected to its terminals for the load path between the input E and a Intermediate node K provided. The switching input of the switch Sc is connected to the switching input S. The coil is provided between the node K and the output A. The cathode of diode D is connected to node K and the anode of diode D is connected to ground. The capacitor C is provided between the output and the ground and the anode of the diode of this buck converter.

The switching arrangement 10 contains a higher-level control unit 24 , a first subordinate control unit 25 , a second subordinate control unit 26 , a third subordinate control unit 27 and an nth subordinate control unit 28 , The higher-level control unit 24 controls the control terminal of the switch of the buck converter 20 at. The higher-level control unit 24 also controls the subordinate control units 25 . 26 . 27 and 28 at. The subordinate control unit 25 is to the control terminal of the switch of the buck converter 21 connected, the output of the subordinate control unit 26 is to the control terminal of the switch of the buck converter 22 connected, the output of the subordinate control unit 27 is to the control terminal of the switch of the buck converter 23 connected and the control terminal of the switch of the buck converter 29 is with the output of the slave controller 28 connected. The higher-level control 24 also controls the boost converter 11 and the switching unit 12 ,

The circuit arrangement 10 also has filters 30 . 31 . 32 . 33 and 34 on. These each have an input and an output, between the input and output a coil and between the input and the ground of a capacitor and between the output and the ground another capacitor.

In addition, the circuit contains 10 a bridging arrangement 36 with a first switch 360 , a second switch 361 , a third switch 362 and a fourth switch 363 ,

Furthermore, the circuit arrangement contains 10 a first supply switch 39 , a second supply switch 370 , a third supply switch 371 , a fourth supply switch 372 and a fifth supply switch 373 , The first supply switch 39 is with its first input to the terminal VBAT and with its second connection to each of the first input terminals of the supply switch 370 . 371 . 372 and 373 connected. The supply switches 370 . 371 . 372 and 373 are each selector switches, which connect their output optionally either with its first input or with its second input.

The input of the filter 30 is with the output of the buck converter 20 connected while the output of the filter 30 with the second input of the switch 370 connected is. The input of the filter 31 is with the output of the buck converter 21 connected while the output of the filter 31 with the second input of the switch 371 connected is. The input of the filter 32 is with the output of the buck converter 22 connected while the output of the filter 32 with the second input of the switch 372 connected is. The input of the filter 33 is with the output of the buck converter 23 connected while its output to the input of the switch 373 connected is. The output of the switch 370 is connected to the output of the circuit 10 connected.

The circuit arrangement 10 also has outputs O2, O3, O4 and O5. The output O2 is connected to the output of the switch 371 , the output O3 to the output of the switch 372 , the output O4 to the output of the switch 373 and the output O5 to the output of the filter 34 connected. The input of the filter 34 is with the output of the buck converter 29 connected.

The mentioned switches 370 . 371 . 372 . 373 . 360 . 361 . 362 and 363 are each with their control input from the electronic switch driver 38 driven.

The circuit arrangement 10 has a bridge node 3600 on that with the second connections of the switches 360 . 361 . 362 and 363 connected is. The first connection of the switch 360 is with the output of the filter 30 , the first connection of the switch 361 with the output of the filter 31 , the second port of the switch 362 is with the output of the filter 32 and the first port of the switch 363 is with the output of the filter 33 connected.

Generally, in switches, the terminals of the load path of the switch are referred to as terminals, inputs and outputs, that is, with the switch closed and voltage applied across the terminals, current flows through the terminals, inputs and outputs respectively. The switches are controlled by switching connections which indicate in which position the switch should be located.

The filters 13 . 30 . 31 . 32 and 33 have the purpose of supplying power in the case of the filter 31 or the consumer in the case of filters 30 . 31 . 32 and 33 to protect against electrical noise.

To the outputs of the filters 30 . 31 . 32 and 33 In addition, in each case series circuits of two resistors between these outputs and the ground are provided. With the help of the step-down converter, a first consumer voltage UA2 is connected between the output of the filter 31 and the ground, a second load voltage UA3 between the output of the filter 32 and the ground, a third load voltage UA4 between the output of the filter 33 and the ground and a fourth load voltage UA1 between the output of the filter 30 and the mass produced.

At the junction between the two resistors, a node is provided, each with one of the inputs of the feedback circuit 40 is connected so that each of the inputs of the feedback circuit 40 is connected to exactly one node between two resistors of one of the series circuits. This feedback circuit 40 contains voltage measuring circuits which measures the voltage at said node and the result of this measurement to the higher level control 24 outputs. The circuit arrangement 10 also has a microcontroller 45 , a CAN bus decoder 43 , a volatile memory 41 and a non-volatile memory 42 on.

The circuit arrangement 10 receives the CAN_H and CAN_L signals from the CAN bus decoder 43 decrypted and sent to the microcontroller 45 to get redirected. The microcontroller 45 also receives that from the circuitry ( 10 ) received signal KL15. The microcontroller 45 controls the higher-level control 24 and the electronic switch driver 38 at. Since signal KL 15 is used for fast initialization of the intelligent converter. This is a possibility implemented in hardware to wake the converter out of sleep mode, in which it should record a negligible quiescent current less than 100 μA.

The above-mentioned switches are implemented as power transistors, for example as power MOSFETs or IGBTs.

The switching unit 12 Switches the first input, which is connected to the terminal VBAT, or the second input, which is connected to the first plates of the capacitors 14 connected to his exit. The switching unit 12 can also connect its two inputs and thereby switch its output high impedance.

The circuit arrangement 10 It can be used in combustion engine, hybrid or hybrid vehicles. The following signals are sent to the microcontroller via the CAN bus, ie via the CAN_H and CAN_L connections 45 and are used for internal evaluation as well as decision making within the circuitry 10 used. The signal SOF (State of Function) is a value in the unit of volts, which is determined by an external computer. Behind this is the pre-calculated maximum voltage dip of the 12 V electrical system during the starting process. The SOC (State of Charge) signal is the quantity used to indicate the charge state of energy storage devices in percent. The state of charge and the temperature, as well as the aging significantly determine the starting strength of the energy storage.

Furthermore, the microcontroller receives 45 the battery voltage, the brake signal bit, which is either false or true. The brake signal bit is not used when the engine speed is below a predetermined threshold. In addition, the "motor-running bit", which may also be either true or false, will signal the "auto-start bit" signal, which may also assume the values to be false or true, and the "ignition-on" signal generated by the "auto-start bit" CAN bus or via its own line is initialized, transferred. In addition, the signals "start request" and "power demand from consumers" are used, these two signals being sent via the CAN bus.

The signals "emergency request for door closers" and "battery defective, battery off or destroyed" are also from the microcontroller 45 evaluated.

The circuit arrangement 10 collects this information during each ignition cycle and stores the data in the non-volatile memory before the circuit is switched to a sleep mode 42 , In addition, the internal state of the converter should always be checked, during or before the ignition process. The data obtained should be saved.

If the data coming from a battery controller that controls the battery is invalid, part of the energy management can be used to let the converter make its own decisions based on its own calculation algorithms to calculate state of charge. For example, the converter decides which loads should be connected to the battery before the engine is running. The calculated values should be saved as backup information for a defined time. After this time an error message will be sent.

The converter, with the help of the microcontroller 45 , make your own decisions, for example, if the door control unit should continue to be connected to the electric vehicle system or if it should already get energy from the power supply before the engine is running.

The use of additional energy storage elements to a higher voltage level helps to avoid a negative impact on the starting behavior in case the power requirements are higher than 500W. This is done by using the extra stored energy during cranking, with the boost converter being deactivated. An activated boost converter would additionally break the voltage.

The converter uses first voltage limits specific to the normal functions of the components to decide on the correct functional behavior of the power distribution.

The converter also uses second voltage limits, which are specific to components during cranking, to decide on the correct functional behavior of the power distribution.

The first operating mode, also called mode I, is the start mode. In this is the vehicle, if after a standstill with the ignition off, the ignition key to start the vehicle is turned and the engine is not yet started. In this mode, the microprocessor loads the data stored in the non-volatile memory and receives the above-mentioned signals to determine which loads are connected to the battery. For those consumers who are connected to the battery, the associated power switch 370 . 371 . 372 or 373 switched so that its first input is connected to its output. In addition, the power switch 39 closed.

An automatic start procedure in the context of an automatic start stop can only be initialized if the autostart bit is set to true. It is assumed that the auto-start bit is set to true only if the first manual start of the engine was successfully completed within the first attempt at ignition. Otherwise, the autostart bit is set to false, because then there is an increased risk that even an automatic start will not be instant. The autostart bit is also set to false when the ignition is off. The auto-start bit may also be set to false with the help of a switch that can be operated manually or by safety devices in the vehicle. The circuit arrangement 10 uses components that limit specific operating voltages and limit the starting voltage to ensure correct performance of the power supply.

The manual startup process, hereinafter referred to as Mode II, is initialized by a user who turns the ignition key to the stop or presses a start button in the vehicle to start the engine. The Autostart Bit Signal is set to false because autostart was previously disabled either manually or automatically. The desk 39 will be closed and some of the switches 370 . 371 . 372 and 373 are each switched so that their respective first inputs are connected to their respective first outputs. Thus, a selection of the consumers V1, V2, V3 and V4 connected to the outputs O1, O2, O3 or O4, respectively, from the battery 1 directly over the mentioned switch 39 . 370 . 371 . 372 respectively. 373 supplied by the battery voltage.

The circuit arrangement 10 receives from the ignition key the signal that the engine should be started. According to the signals SOF and the SOC and the priority list decides the voltage arrangement before starting, a) which consumers are to be turned off and b) which consumers are powered directly from the battery, without this having a negative impact on the starting process. For this purpose, a load calculation is performed. In addition, it is decided to c) which components will be turned on after the engine has been successfully started.

For example, the load V1 supplied from the output O1 should be directly supplied by the battery, and the load V2 connected to the output O2 should be turned off. This will be the switch 39 closed and the switch 370 so laid out that he connects his first entrance with his exit. The second switch 371 is switched so that its second input is connected to the output. The desk 361 stays open and the down converter 21 is inactive. Thus, the consumer connected to port O2 is not powered.

The so-called startup process is referred to as Mode III. The auto-start process is the automatic start of the engine without the user having to initiate the startup.

The auto-start process is particularly necessary in automatic start / stop, in which the engine is switched off when the traffic light stops. Pressing the clutch restarts the engine automatically without the driver having to turn an ignition key or press a start button. The autostart bit is set to true at the beginning of the process. If the capacitors 14 not loaded to a higher voltage, but to the same voltage as the battery, the comparator switches to the so-called bridged mode and the circuit arrangement operates as in the mode II.

If the capacitors 14 are charged to higher voltage than the battery - this is done for example by recuperation in the past - is the switching unit 12 placed so that the inputs of the buck converters 20 . 21 . 22 and 23 over the filter with the first plates of the batteries 14 are coupled.

According to the charging status of the capacitors 14 , the signals SOC and SOF and the priority list decides the circuitry 10 which consumers of the stored energy in the capacitor 14 getting charged. This is done by means of a load calculation which estimates how much energy the individual consumers are expected to consume. It also calculates if it is necessary to have multiple outputs of the downconverters 20 . 21 . 22 and 23 cascade, for example, because the battery's charging status is poor.

In one example, the consumers V1, V2, V3 should each be powered by a buck converter, while the consumer V4 should not be powered. It will be the switch 39 opened, as well as the switches 360 . 361 . 362 and 363 , The switches 370 . 371 and 372 are each switched so that their second inputs are connected to their output, while the switch 373 is switched so that its first input is connected to the output.

It is also decided in mode III, which consumers who are not absolutely necessary for the functioning of the vehicle, nevertheless supplied in order not to disappoint the user of the vehicle.

Mode IV is the recuperation mode. The circuit arrangement 10 has the ability to store energy during vehicle braking or during a vehicle deceleration process. This energy is in the capacitors 14 saved. In addition to the capacitors 14 , parts of the circuit 10 As mentioned above, additional capacitors can be connected to the EXT_S terminal. These additional memories may be capacitors or accumulators or the like.

The energy that is converted into electrical energy during braking or deceleration of the vehicle is first used to increase the battery voltage. Subsequently, this energy is using the boost converter 11 in charge energy of the capacitors 14 or the additional external capacitors converted. The circuit arrangement 10 should have a boost converter 11 use, which has low power dissipation, in order to achieve higher voltage values, so that more electrical energy in the buffer, that is in the capacitors 14 and in the external memory, can be stored. The energy W is calculated from W = ½ · capacity · voltage ² . The higher the voltage, the more energy can be stored.

Depending on the state of charge of the stored energy, it may also be used to additionally provide energy components that have additional short-term power requirements. This extra energy has to go through the internal energy management to avoid disturbing the starter supply. Therefore, it is necessary to request additional energy to the circuitry 10 to send over the CAN bus.

The recuperated energy should be stored for a few weeks by avoiding leakage during standstill of the vehicle and by using a low self-discharge rate capacitor.

The energy storage capacity is initially limited by the capacity of the internal memory. Additional external storage elements such as capacitors, accumulators, etc. increase the capacity. The loaded voltage level is ramped up to avoid high input currents, especially when no brake is activated.

As mode V, the emergency energy supply mode is also called emergency mode. Due to the legal requirements regarding electric door lock systems, an output of the supply circuit is provided only for the door locks except for the trunk lock. This output has a higher priority. In the event that the battery voltage becomes too low, an accident is detected, the battery voltage is no longer there or the battery is destroyed, a battery malfunction is detected. The door locks must be controlled so that a distinction is made between an emergency energy supply and a permanent power supply.

To a malfunction within the circuit 10 To avoid this, the internal power supply must be guaranteed. For this purpose, the control circuits, such as the microcontroller 45 and the controls 24 . 25 . 26 . 27 and 28 supplied in this case by an additional storage, which was fed by a charge pump.

The circuit arrangement 10 reacts as follows: All non-affected consumers, that is, all unnecessary consumers are turned off. All down-converters 20 . 21 . 22 be over the switches 360 . 361 . 362 and 363 bundled and provide the emergency connection with voltage. In addition, a request to open doors to the doors is sent via the CAN bus.

It is assumed that the door locks are supplied via the O3 output. Then the switches 360 . 361 . 362 . 363 closed. The desk 372 is wired so that its second input is connected to its output while the switches 370 . 371 and 373 be wired so that their first inputs are each connected to their outputs. The desk 39 will be opened. The down-converters 20 . 21 . 22 and 23 are all operated. Consequently, all energy flows from the buck converters 20 . 21 . 22 and 23 to the exit O3. The down-converters 20 . 21 . 22 and 23 are thus operated in parallel and the output power provided is greater than if only one of the downconverters 20 . 21 . 22 and 23 would be operated.

In addition, the stored energy is provided as emergency power not only to the door opening system but also to the necessary additional control logic. These are the battery control unit BCM, the central locking and so on. This is necessary so that the drive signals for opening the actuators are properly distributed.

It is assumed that the battery is very empty, an accident has been detected, the battery is off, or the battery supply has been destroyed. This is signaled in each case with the signal "battery error detected". The DC-DC converter then decides to switch from the standard supply mode to the emergency mode. To prevent that within the DC-DC converter If a malfunction occurs, the internal power supply for this converter must be guaranteed.

For this purpose, additional storage elements are carefully loaded by means of a start-up charge current control function, which has a small influence on the vehicle deceleration.

The DC-DC converter responds as follows:
All downconverters are bundled to provide the maximum possible power at an emergency exit. At this emergency exit are the door opening system and the necessary control circuits for the door opening system.

Subsequently, an emergency door opening request to the appropriate control unit, for example, the BCM sent over the CAN bus or via its own line.

Mode VI is the so-called shutdown mode. If a vehicle is parked at an airport for several weeks, for example, the energy consumption should be reduced as much as possible. The capacitors 14 are charged directly from the battery. For this purpose, the switching unit connects 12 its inputs with each other and switches its output high impedance. The capacitors thus remain charged at a lower voltage level, thereby avoiding increased aging processes that would occur at even lower voltages. At the same time, the self-discharge currents, which increase with increasing voltage, are kept as low as possible.

In addition, the power supply has 10 programmable output terminals for consumers with low voltage levels. These outputs can be used for bus systems and sensors with predetermined input voltage levels. One of these outputs is the O5 output.

The programmability of the consumer voltage level is not used for the main supply outputs, which must all have the same voltage level. If the voltage supply can be achieved, also by reducing the voltage levels at these outputs, this can only be done if all the voltage levels are lowered simultaneously.

The low voltage levels would have to be adapted to the needs of consumers who would be directly affected by this requirement. The down converter 29 can be set to vary its output voltage. The output voltage of the buck converter 20 . 21 . 22 and 23 are each set to the same output voltage value.

To get energy from the capacitors 14 and the battery is provided to convert to a certain voltage level, the buck converters are used. These buck converters can be set for different powers, ie output currents and different voltage levels, by software programming in terms of their output parameters. The four high-performance buck converters 20 . 21 . 22 and 23 Each should provide the same output voltage so that it is possible to connect the outputs together to provide the highest possible output power.

The up-converter 11 is activated during vehicle deceleration or during braking so that the energy is stored at a higher voltage level. This voltage level is for example 28 V. During recuperation all consumers should be connected directly to the battery. The voltage across the capacitors 14 is set within a minimum voltage level and a maximum voltage level. According to the voltage levels of the capacitors 40 Consumers can be supplied with recuperation energy directly from this down-converter 11 comes without this having a negative impact on the starting process later.

2 shows a further embodiment of the supply circuit in particular to support the emergency operation. Elements having the same functions as in the above figures are identified by the same reference numerals and will not be explained again.

Compared to 1 has the circuit arrangement 10 no up-converter 11 on. The first load voltage UA2, the second load voltage UA3, the third load voltage UA4 and the fourth load voltage UA1 are respectively from the downconverters 20 . 21 . 22 . 23 generated directly from the battery voltage UBAT. Alternatively, boosters or simple switches can be used instead of the downconverters 20 . 21 . 22 . 23 be used. The embodiment according to 2 has fewer components, is therefore technically more modest. The embodiment according to 1 on the other hand has the advantage that the buffer can compensate for consumption peaks particularly well.

LIST OF REFERENCE NUMBERS

1

Lead-acid battery

10

circuitry

11

boost converter

12

switching unit

13

filter

14

capacitor

20

down converter

21

down converter

22

down converter

23

down converter

24

higher-level control

25

subordinate control

26

subordinate control

27

subordinate control

28

subordinate control

29

down converter

30

filter

31

filter

32

filter

33

filter

34

filter

36

bridging arrangement

38

electronic switch driver

39

supply switch

40

Voltage feedback

41

volatile memory

42

non-volatile memory

43

CAN bus decoder

45

microprocessor

110

transformer

111

switch

112

diode

360

switch

361

switch

362

switch

363

switch

370

switch

371

switch

372

switch

373

switch

3600

node

O1

output

O2

output

O3

output

O4

output

O5

output

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely 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.

Cited patent literature

• US 7236893 B1 [0002]

Claims (15)

Supply circuit for the electrical supply of a vehicle, comprising: - a battery ( 1 ) for generating a battery supply voltage; A first power supply unit ( 21 ) for generating a first load voltage (UA2), the first load voltage (UA2) for supplying a first load (V2); A second power supply unit ( 22 ) for generating a second load voltage (UA3), the second load voltage (UA3) for supplying a second load (V3); A control circuit ( 45 . 24 . 25 . 26 ) for controlling the first power supply unit ( 21 ) and the second power supply unit ( 22 ), wherein the control circuit ( 45 . 24 . 25 . 26 ) is configured such that in an emergency mode of the vehicle, the second load (V3) is supplied by the first load voltage (UA2) and by the second load voltage (UA3) and the first power supply unit ( 21 ) generates the first load voltage (UA2) and the second power supply unit ( 22 ) generates the second load voltage (UA3). A supply circuit according to claim 1, wherein the second load (V3) is a door lock mechanism of the vehicle. A supply circuit according to claim 1 or 2, wherein the second load (V3) is a restraining mechanism of the vehicle. Supply circuit according to one of the preceding claims, wherein in the emergency mode, the first consumer is powered from any voltage supply. Supply circuit according to one of the preceding claims, wherein the supply circuit additionally comprises: - an up-converter ( 11 ) for generating an intermediate voltage (UZ) from the battery supply voltage (UBAT); - a cache ( 14 ) for storing electrical energy, the buffer ( 14 ) is supplied by the intermediate voltage (UZ); and wherein the first supply circuit is a first down-converter ( 21 ) for generating the first consumer voltage (UA2) from the intermediate voltage (UZ), and the second supply circuit a second buck converter (UZ) 22 ) for generating the second load voltage (UA3) from the intermediate voltage (UZ), the second load voltage (UA3) for supplying a second consumption (V3); and the control circuit ( 45 . 24 . 25 . 26 ) in addition to controlling the up-converter ( 11 ) is set up. Supply circuit according to one of the preceding claims, characterized by a switch ( 371 ) for connecting the first load (V2) to a supply node of the battery voltage (UBAT) and another switch ( 372 ) for connecting the second load (V3) to a supply node of the battery voltage (UBAT). Supply circuit according to one of the preceding claims, characterized by a switch ( 361 ) for connecting the first load (V2) to the first load voltage (UA2) and another switch ( 372 ) for connecting the second load (V3) to the second load voltage (UA3). Supply circuit according to one of the preceding claims, characterized by at least one switch ( 362 . 363 ) for connecting a supply node of the first load voltage (UA2) with a supply node of the second load voltage (UA3). Supply circuit according to one of Claims 1 to 8, characterized in that the control circuit has a higher-level control ( 45 . 24 ) and two subordinate controls ( 25 . 26 ), wherein a first subordinate control ( 25 ) the first buck converter ( 21 ) and the second subordinate control ( 26 ) the second buck converter ( 22 ) and the higher-level control ( 45 . 24 ) the first subordinate control ( 21 ) and the second subordinate control ( 22 ). Supply circuit according to one of Claims 1 to 9, characterized by a further switch for connecting a supply node of the battery voltage (U _BAT ) to a supply node of the intermediate voltage (U _Z ). Supply circuit according to one of the preceding claims, characterized in that a housing for receiving the supply circuit ( 10 ) and a connection (EXT_S) of the housing for connection of external buffer are provided. Supply circuit according to one of Claims 1 to 11, characterized in that a measuring circuit ( 40 ) is provided for measuring the first load voltage (UA2) and the second load voltage (UA3). Supply circuit according to one of Claims 1 to 12, characterized by a third down-converter ( 29 ) for generating a third load voltage (UO5) for supplying a third load (V5) from the intermediate voltage (UZ), wherein the voltage level of the third load voltage (UO5) is adjustable independently of the first load voltage (UA2) and the second load voltage (UA3) , Motor vehicle with a supply circuit according to one of claims 1 to 13. A method of operating a supply circuit according to any one of claims 1 to 13 in a vehicle, the method comprising an operating mode of a vehicle in which the second load (V3) is supplied by the first load voltage (UA2) and the second load voltage (UA3) and the first buck converter ( 21 ) generates the first load voltage (UA2) and the second buck converter ( 22 ) generates the second load voltage (UA3).

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