EP1269595A1

EP1269595A1 - Device for the disconnection and connection of a load

Info

Publication number: EP1269595A1
Application number: EP01985927A
Authority: EP
Inventors: Roland Mauser
Original assignee: DaimlerChrysler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2001-02-07
Filing date: 2001-12-22
Publication date: 2003-01-02
Also published as: DE10105457A1; WO2002063738A1; JP2004518398A; US20040100236A1

Abstract

According to the invention, a safe plugging-in of a fuse or a plug, without creating an arc may be achieved, whereby a device (1) for the disconnection and connection of a load (2) is provided with a control device (4) and a switching element (14), arranged between a voltage supply (6) and the load (2) and connected to the control device (4). An input (16) for the control device (4) is provided between the voltage supply (6) and the switching element (14), for the monitoring of at least one voltage threshold, whereby the control device (4) deactivates the switching element (14) on falling below a first voltage threshold.

Description

Device for disconnecting and switching a load

The invention relates to a device for disconnecting and switching a load, in particular a consumer in a vehicle.

To supply power to various electrical consumers, a vehicle comprises at least one electrical system and a control device for controlling the respective consumer. The vehicle electrical system usually has a fuse, which in the event of a short circuit, e.g. in the wiring, or is triggered by a defect in the consumer. When plugging in a plug or the fuse after troubleshooting, an arc can occur when the consumer is switched on. Which in turn damaged or welded the contacts in question.

The invention is therefore based on the object of specifying a device for disconnecting and switching a load, with which it is possible to insert a fuse or other plug without the occurrence of an arc.

The object is achieved according to the invention by a device for disconnecting and switching a load with a control device and with a switching element arranged between an on-board electrical system and the load, which is connected to the control device, and with an input provided for the control device between the on-board electrical system and the switching element for monitoring at least one voltage limit value, the control device deactivating the switching element when the voltage falls below a first voltage limit value. This ensures that the consumer or the load is de-energized in the event of a fault in the vehicle electrical system by means of the deactivated switching element. This prevents the occurrence of an arc when the fuse is inserted. A possible disconnection of the supply battery or the electrical system can be omitted. The use of a switching element provides a particularly simple device which can also be retrofitted into existing systems in a vehicle without great effort. The control device or the control device preferably deactivates the switching element when the voltage from the vehicle electrical system, which is tapped at the input before the switching element, falls below the first voltage limit value, in particular a value of less than 2V. Depending on the type and design of the voltage supply in a vehicle, for example 14V electrical system, 42V electrical system or 60V battery or mixed supply voltage, a corresponding first voltage limit value can be set in the control device. The first voltage limit value is then compared by means of the control device with the voltage value present at the input. If the voltage value measured at the input is less than or equal to the first voltage limit value, the switching element is deactivated by means of the control device.

The control device expediently activates the switching element when a second voltage limit value is exceeded. A value corresponding to the respective supply voltage is preferably specified as the second voltage limit value. For example, with a 42V vehicle electrical system, a value of greater than 30V is set as the second voltage limit. Depending on the embodiment of the control device, the switching element is preferably activated after a predeterminable time has elapsed or when a function request is present. For example, after the fuse has been inserted and the second voltage limit value has been exceeded at the input of the control device and when the vehicle is restarted, the switching element is activated on the basis of the position of the ignition lock. Alternatively or additionally, the switching element is switched on after the fuse has been inserted and the second voltage limit value has been exceeded at the input Control device and activated after a predetermined time.

A semiconductor element or a relay is expediently provided as the switching element. Electronic analog switches, such as diodes, bipolar transistors, field-effect transistors, which enable fast and precise switching, are used as semiconductor elements, for example. In particular in the case of electric motors, which are usually controlled via pulse width modulation, semiconductor switching elements are provided on account of the high switching frequencies.

In the event that the control device and the load are jointly protected by a fuse element, the switching element can be switched with a time delay when the second voltage limit value is exceeded. This ensures that the control device is first supplied with voltage before the load is switched, so that the criteria required for switching the load are checked by the control device. In other words: Is there a voltage at the input of the control device that characterizes the safe operation of the voltage supply, i.e. If the value is above the second voltage limit, the load is only switched by activating the switching element after a predetermined time has elapsed. The occurrence of an arc is thus reliably avoided.

The advantages achieved by the invention consist in particular in that, based on the continuous monitoring of the voltage from the on-board electrical system, an undershoot of a critical voltage limit value is determined, by means of which the switching element is deactivated by means of the control device until a normal voltage level of the on-board electrical system is detected. This ensures that a fault in the vehicle electrical system which causes the critical voltage value and which triggers the fuse can be remedied by plugging in the plug connections or the fuse without causing an arc. This is also ensured if the load is still switched on that the branch between the vehicle electrical system and the load is separated by means of the switching element. This also avoids costly disconnection of the supply battery. In addition, the control device automatically enables the switching element after the fault has been rectified.

Embodiments of the invention are explained in more detail with reference to a drawing. In it show:

1 schematically shows a device for disconnecting and switching a load with a control device and a

Switching element, FIG 2 schematically shows a device according to Figure 1, with a common power supply for the load and

Control device, and FIG 3 schematically shows an alternative device according to FIG

1.

Corresponding parts are provided with the same reference symbols in all figures.

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Claims

claims

1. Device (1) for disconnecting and switching a load (2) with a control device (4) characterized by a switching element (14) arranged between a voltage supply (6) and the load (2) and connected to the control device (4) , and an input (16) provided between the voltage supply (6) and the switching element (14) for the control device (4) for monitoring at least one voltage limit value, the control device (4) deactivating the switching element (14) when the voltage falls below a first voltage limit value.

2. Device according to claim 1,

That means that the control device (4) activates the switching element (14) when a second voltage limit value is exceeded.

3. Apparatus according to claim 1 or 2, d a d u r c h g e k e n n z e i c h n e t that a semiconductor element or a relay is provided as the switching element (14).

4. Device according to one of claims 1 to 3, characterized in that the control device (4) and the load (2) are jointly secured by a fuse element (10), the switching element (14) with a time delay when the second voltage value is exceeded is switchable.