WO2011134767A2

WO2011134767A2 - Power supply system for an electrical load in a motor vehicle

Info

Publication number: WO2011134767A2
Application number: PCT/EP2011/055364
Authority: WO
Inventors: Thomas Schulz; Rainer Mäckel
Original assignee: Auto-Kabel Managementgesellschaft Mbh
Priority date: 2010-04-29
Filing date: 2011-04-06
Publication date: 2011-11-03
Also published as: DE102010018777A1; WO2011134767A3

Abstract

The invention relates to a power supply system for at least one electrical load (12) in a motor vehicle, at least one motor vehicle power supply system having at least one power accumulator (14) being provided, said power accumulator (14) being charged by a generator (11). According to the invention, the electrical load (12) is electrically connected to the motor vehicle power supply system by means of a current intensity controlling device (13) for controlling current intensity.

Description

Energy supply system for an electrical consumer in a motor vehicle

The invention relates to a power supply system for an electrical consumer in a motor vehicle, according to the preamble of claim 1. Furthermore, the present invention relates to a motor vehicle according to claim 9 and a method for supplying energy to at least one electrical load in a motor vehicle

according to the preamble of claim 10.

In order to reduce fuel consumption and thus CO 2 emissions, modern motor vehicles are increasingly equipped with a so-called stop / start automatic transmission. In the process, the engine becomes during idle periods lasting longer

automatically shut off. To restart, it is sufficient if the driver presses the accelerator pedal and accelerates.

In order to do this, the starting speed required for the start of an internal combustion engine (minimum speed)

ensure a so-called starter (starter) is used. This includes in most cases a starter electric motor, which is powered by electrical energy. Because at standstill of the engine

Motor vehicle generator does not generate electricity, the

electrical energy for operating this starter electric motor an electrical memory, for example in the form of a Accumulator be removed. Since the starter electric motor is a high-performance consumer, it comes through the starting process to voltage drops, which function losses in all connected to the electrical storage other electrical loads, such. B. the car radio, can result.

In the prior art systems are known, which are supported by a second electrical memory in the form of a battery, which is connected to the electrical system. in the

Warm start case will be the starter circuit over the first

Accumulator supplied.

By suitable switching elements, the rest of the electrical system, which is then supplied via the second accumulator, separated from the starter circuit. DE 102007062955 A1, for example, discloses a circuit for voltage stabilization of a vehicle electrical system, which is arranged between the vehicle electrical system to be stabilized and a first accumulator. The circuit comprises a diode element which includes a plurality of parallel-connected semiconductor switches, a control and

Control circuit showing the strength of the

Diode element flowing current determined and corresponding to the specific current strength of the semiconductor switches

Diode element controls, and one with the diode element and the electrical system electrically connected second accumulator.

However, these systems have the disadvantage that at least two accumulators are needed. Since accumulators have a relatively high weight, are relatively expensive and have only a limited life, the use of a second accumulator is disadvantageous. Also state of the art are systems that the to

Supply the starter necessary electrical energy not from an accumulator, but pull out of a capacitor. For example, DE 10 2007 025 694 A1 discloses a

electrical wiring system which has a starter, one

Accumulator, a generator, and at least one

includes electrical consumers. The starter and

at least one capacitor comprising the first part of

Onboard network is via a DC / DC converter with a the

Generator, the accumulator and the electrical consumers comprehensive second part of the electrical system connected, wherein the capacitor via the DC / DC converter electrical energy from the second part fed and the starter with electrical

Energy from the condenser is operable. A disadvantage of this solution is that the capacitor used, due to the fact that the starter requires a relatively large amount of energy, has a large capacity and must be dimensioned accordingly. The weight of such

Condenser in turn leads to an increased

Fuel consumption, which is undesirable.

The object of the invention is to provide an improved, cost-effective as possible energy supply system, which prevents it by a restart of the

Motors to voltage dips comes, which have a loss of function in electrical equipment connected to the electrical system. In addition, this energy supply system should have as little weight as possible. This object is achieved by a power supply system according to

Claim 1, a motor vehicle according to the sibling Claim 9 and a method for power supply according to the independent claim 10. advantageous

Embodiments of the invention are the subject of

Subclaims.

According to the invention it is provided that the electrical

Consumer is electrically connected via a current control device for controlling the current with the vehicle electrical system. The essential thought of

Invention is that the amperage control means ensures that the voltage value in the motor vehicle electrical system, which comprises at least one generator and an electric storage, not one

Threshold drops. This prevents such a high voltage drop from occurring due to a restart, that the electrical devices connected to the motor vehicle electrical system suffer a loss of function.

The electrical storage may be any suitable means for buffering electrical energy. In particular, the energy storage a

Include (lead) accumulator battery.

Preferably, the current-strength control device is designed as a transductor, wherein the transductor is constructed as a coil whose inductance is changed by a change in the bias of its core. The core gets by a control current, which flows through a second winding, more or less in the region of saturation, whereby the total resistance in the

AC circuit changes. As a result, especially high, fast current peaks, which are responsible for the voltage dip responsible are to be limited.

In a further preferred embodiment, the

Amperage control means an analysis device which can detect whether a cold start scenario is present and in this case reduces the inductance of the transductor. A cold start scenario is present when the engine is to be restarted for the first time after a longer standstill. As needed to start the engine

Minimum speed is relatively high in this case, the starter requires comparatively much energy. Preferably, the core of the transducer is therefore controlled to saturation and the inductance is thus reduced. The analysis device makes it possible with the help of sensor, operating and

Condition information to detect whether the engine should be restarted for the first time after a longer service life. Preferably, the sensor, operating and

Status information obtained by so-called polling (cyclic queries). Equivalent, however, is the use of interrupt requests or a recursive setup.

Preferably, the current-strength control device is designed as a semiconductor switch. The skilled person is aware that semiconductor switches in contrast to mechanical

Switches are sensitive to overloading. in the

Overload case can be a so-called

"Durchlegieren" come of the semiconductor switch, the semiconductor switch is then permanently conductive and can not be turned off. Since such an overload is triggered here only by the current peaks in the boot process, the Semiconductor switch thermally only briefly loaded. Breaking down is therefore extremely unlikely. In order to exclude the failure of the semiconductor switch are known to the expert various ways.

For example, two semiconductor switches or a

Semiconductor switch and a thermal protection element are connected in series. By a thermal coupling, the thermal protection element, z. As a fuse, in case of overheating of the semiconductor switch and separates the current path to the semiconductor switch.

Further preferably, the semiconductor switch is a

Field effect transistor, preferably a metal oxide semiconductor field effect transistor (MOSFET). That I

By switching field effect transistors with extremely short time delay, their use enables them to respond quickly to changes in current flow. However, the skilled person is clear that any other semiconductor switch, such. B., thyristors, triacs or bipolar transistors

can be used.

In a further preferred embodiment, the

Amperage control device, an analysis device, which is designed such that in the case of the presence of a warm start scenario, the semiconductor switch is operated in the linear range and thereby the function of a

adjustable resistance met. A warm start scenario is always present when the engine is to be restarted after a relatively short service life. Here, too, the analysis device makes it possible, with the aid of sensor, operating and status information, to detect whether the engine is restarted after a short service life should. Preferably, the sensor, operating and

Preferably, the amperage control means includes a measuring device which determines the temperature of the

Semiconductor switch measures. Advantageously, this temperature can be used as a monitoring criterion for the duration of the operation of the

Semiconductor switch can be used in the linear range. It is also possible that the circuit is only time-limited

to prevent overheating of the switch. Further preferably, the consumer comprises a starting electric motor for starting an internal combustion engine. It is of course equally conceivable that other high-performance consumers such. B. electro-hydraulic

Brakes or a power steering must be secured accordingly.

Finally, the invention relates to a motor vehicle with the energy supply system according to the invention and a

Method for supplying energy to at least one

electrical consumers in a motor vehicle

Use of such a power supply system.

In the following the invention will be explained in more detail with reference to the drawing. Showing:

Fig. 1 is a block diagram of a preferred

Embodiment of a power supply system Fig. 2 is a block diagram of an embodiment of a

Energy supply system with a coupled halved switch,

Fig. 3 is a schematic representation of a

Embodiment of an energy supply system with a coupled-in transductor and Fig. 4 is a diagram showing the voltage curve in

Represents motor vehicle electrical system with and without limitation by a current control device. FIG. 1 shows, in the form of a block diagram, a preferred embodiment of a power supply system whose components are a generator 11, a consumer 12

Energy storage 14 and a current control device 13 are. All components of the power supply system are electrically connected, for example by electrical lines. The generator 11 and the energy storage 14 represent schematically the motor vehicle electrical system, which supplies further, not shown here consumers. The amperage control device 13 is between the

Consumer 12 and the other components of the

Switched power supply system and can, depending on the trouble for the operation of all other electrical loads of the vehicle electrical system necessary

Voltage, how much power control the electric

Consumer 12 is made available. This can ensure that the voltage in the Motor vehicle electrical system not under a stipulated

Threshold can drop.

Figure 2 shows, also as a block diagram, a

Embodiment of a power supply system of Figure 1, wherein the amperage control means 13 a

Semiconductor switch 23 includes. There are also one

Charge pump 21, a control device for the

Semiconductor switch 22, a voltage sensor 24, a

Voltage reference device 25 and an electrical

Consumers 12 provided. The voltage reference device 25 is a circuit or a component that provides (for comparison) an accurate voltage. Again, all components of the power supply system are electrically connected, for example, by electrical wires. The voltage sensor 24 measures the voltage present in the motor vehicle electrical system. This is going through with the

Voltage reference device 25 compared voltage provided. If the voltage gets so small that one

Threshold falls below, the switches

Voltage reference device 25 so far by that the semiconductor switch 23 is brought via the control device 22 in the linear range, and limits the starter current so far that a minimum value for the voltage in the motor vehicle electrical system is not exceeded. Alternatively, the semiconductor switch can also be driven in pulsed mode. The skilled person is clear that the

Current control device 13 is not a single component, but is functional to understand.

The semiconductor switch can also be used as a line protection element (overcurrents), or in the non-driven Case of the consumer in lock-up operation. A voltage source (eg generator) could additionally be behind the semiconductor switch. About a current direction detection and a threshold (consumer not driven) could lock the semiconductor switch, and thus a

Ensure line protection / wiring system protection. As a result, the elimination of a backup is possible. The consumer (i.e., here the starter) is normally de-energized (i.e., no starting operation).

Figure 3 shows the schematic representation of a

Transducer includes. In addition, an electrical memory 14, a magnetic core 31, windings 32 which extend around the core 31, a control line 33 and a

electrical consumer 12 available. Around the magnetic core 31 run two different windings. The first winding, which is located between the electrical storage 14 and the electrical load 12 is the

Load circuit. The second winding is traversed via the control line 33 by a control current, via which the

Inductance of the transducer can be controlled. As a result, especially high, fast current spikes, which are the cause of a voltage dip in the motor vehicle electrical system, can be limited. Of course, an analysis and control device is necessary for the control, which regulates the control current, depending on the occurring Spannungss itzen. This analysis and control device is not shown here. Furthermore, consumers can be connected, which are not powered by the device for controlling the current. Here, too, then the regulation is active by adjusting the current through the regulated load so that the voltage in the electrical system remains constant, even if additional currents flow in the other consumers and load the electrical system.

4 shows in the form of a diagram the voltage curve in the motor vehicle electrical system with 44 and without 43 limitation by a current-control device 13. The x-axis of the diagram 41 represents the time axis. The y-axis of the diagram 42 represents the battery voltage. In addition a voltage threshold 45 is shown. It can be seen that the voltage in the motor vehicle electrical system without 43, the limit by a current control device 13 can fall below the voltage threshold 45 - 44 with a limitation by a current control device 13 but not. The voltage threshold 45 can be, for. B. on the selection of the voltage reference device 25 set very accurately.

Claims

claims

Energy supply system for at least one electrical consumer (12) in a motor vehicle,

- At least one electrical system with at least one

electrical memory (14) is provided

- wherein the electrical memory (14) by a

Generator (11) is charged

characterized in that the electrical load

(12) is electrically connected via a current control device (13) for controlling the current intensity with the motor vehicle electrical system.

Power supply system according to claim 1, characterized

characterized in that the amperage control means

(13) contains a transductor.

Power supply system according to claim 2, characterized

in that the current-strength control device (13) contains an analysis device which can detect whether a cold-start scenario exists and in this case reduces the inductance of the transductor.

Power supply system according to claim 1, characterized

in that the current-control device (13) contains a semiconductor switch.

Power supply system according to claim 4, characterized

characterized in that the semiconductor switch on Field effect transistor, preferably a metal oxide semiconductor field effect transistor (MOSFET), is.

Power supply system according to one of claims 4 or 5, characterized in that the amperage control means (13) comprises an analysis device

contains, which is designed such that in the case of the presence of a warm start scenario, the semiconductor switch in the linear region, the function of an adjustable

Resistance fulfilled or the semiconductor switch in the

pulsed operation regulates the current.

Power supply system according to one of claims 4 to 6, characterized in that the current-strength control means (13) includes a measuring device which measures the temperature of the semiconductor switch.

Energy supply system according to one of claims 1 to 7, characterized in that the consumer (12) comprises a start-Elektromotor for starting an internal combustion engine.

Energy supply system according to one of claims 1 to 8, characterized in that further unregulated

Consumers are present in the electrical system and the

Amperage control device (13) regulates the current in the electrical system with the consumer connected to the amperage control device.

Method for supplying energy to at least one electrical load (12) in a motor vehicle using a power supply system according to one of the Claims 1 to 8, characterized in that the electrical load (12) via a current strength control device (13) is supplied from the vehicle electrical system with power, wherein the amperage control device (13) has a transductor or a

Semiconductor switch (23) contains.