FI109846B - Power distribution system for vehicles, has converter circuit whose output voltage is selected by controlling timing of ON/OFF pulses of switch - Google Patents

Abstract

A node (2) has a controlled current switch (7) that connects a power bus (1a) to output (4), for supplying current to a load. The output voltage of a converter (3) provided between the switch and output of the node, is selected by controlling timing of ON/OFF pulses of the switch.

Description

109846

Intelligent power distribution system with optional output voltage.

The present invention relates to an intelligent power distribution system operating on an optional output voltage, comprising a cable with power supply conductors and an intelligent node 5 having a controlled power switch through which the power conductor connects to the node output connector to supply power to the load controlled by the intelligent node.

Such power distribution systems are known in the prior art, e.g., from WO 99/25585 and WO 99/25586 of the applicant. These 10 publications also provide a more detailed description of the operation and structure of smart nodes, which are referred to herein as the prior art upon which the present invention is based.

The automotive industry is moving to a 42 V system in the next few years. However, 15 V units will be included in the initial phase for a number of years, as it is technically not possible to change all units without a transition period of several years. This causes the need for both 42V and 12V batteries in the same car.

20 Similarly, the current 24 V systems are moving (somewhat from the passenger side; later) to the 42 V system, which will require some time alongside; 24 V power supply.

It is an object of the present invention to provide an intelligent, 25-hand power distribution system of the type mentioned above which, in addition to power supply voltage, provides an optional output voltage for one or more intelligent system nodes.

, ·. This object is achieved by the invention in the appended claim 1 *; 30. Preferred embodiments of the invention are disclosed in the dependent claims.

* »· 1» 109846 2

In the following, an embodiment of the invention will be described in more detail with reference to the accompanying drawings, in which Figure 1 is a general diagram of the system of the invention and Figure 2 shows an example of a circuit arrangement implementing the voltage option of the invention. In connection with node 2, only the additional features required in the invention in addition to the conventional intelligent node processor, program memory and interface interfaces implemented e.g. with ASIC are provided. For example, reference is made to WO 99/25586.

The power distribution system includes a cable 1 with power supply leads 1a, 1b to which a desired number of smart nodes 2 are connected. Each node 2 has a 15 controlled power switch 7 2 controls this power supply by switching the switch 7 to ON or OFF according to the control messages received from the cable control bus 1 or the INPUT control directly connected to the node 2 to the node 2.

20>. ! In the invention, it has been realized to use the controlled current switches 7 'v of the smart node 2 (typically four pieces in one node 2) also for selecting the output voltage level. For this, there is a wired switch 7 and an output terminal. A converter 3 connected between 4 outputs, the output voltage level of which is selected by the wizard. 25 switch with 7 ON / OFF pulse timing control. The converter 3 may be formed, for example, from a conventional combination of coil L, capacitor C and diode D, • '' *. wherein the pulse voltage applied to coil L charges capacitor C and raises the output voltage of converter 3. When the desired output voltage is reached,. a short pause in pulse output (switch 7 is briefly moved to OFF). The length of the pulse-free pauses is selected according to the load current and the size of the capacitor C so that the output voltage will not be substantially reduced before; new pulse cycle.

109846 3

Alternatively, the pulse rate of the switch 7 is controlled by shortening the pulse duration as the current or voltage tends to increase above the desired value. The upper current limit and / or the desired voltage value can be arranged to be controlled by the control provided by the smart node.

5

The operation of the circuit for controlling the switch 7 for the aforementioned voltage selection and current limitation will now be described in more detail.

The intelligent node 2 has an oscillator 8 which controls the timing of the ON / OFF pulse-10 switches 7. The voltage comparator 9 controls the operation of the oscillator 9 on the basis of a comparison between the voltage measured at the output of the converter 3 and the reference voltage Vref provided by the intelligent node 2 to obtain the desired output voltage of the converter. The configuration of the smart node 2 and the messages coming to the node 2 determine what the desired output voltage is. This function can be utilized, for example, in conjunction with the Headlamp-15 forcing, by reducing only the system's headlamp power supply during daylight hours. For this voltage control, the sensor can be used to sense the exterior lighting and to send information about the illumination level to the nodes 2 which supply power to the headlights. Correspondingly, it is possible to sense, for example, the outdoor temperature and to increase the voltage received by the window motor in frost, in order to remove its possible freezing.

* · · •. ·. The smart node 2 has a two-phase current compression case in the case shown; '. : a generator 10, 11 controlling the operation of the oscillator 8 at the output of the converter 3, "': the measured current after the measuring resistor R and the reference * * ·; 25 tail current lref based on a comparison so that the output current of the converter 3 does not This function can be utilized for the normal current limitation of the actuators and can also be utilized when starting the actuators for the initial current limitation.

• * • * 30 In the case shown, oscillator 8 is equipped with an ENABLE / DISABLE switch /. which is common to the voltage comparator 9 and the current comparator 10, 11.

! Thus, the voltage level selection and the current limitation complement each other so that, if necessary, the voltage is reduced from the selected level, but returns to the selected level when the load current does not exceed the set current limit. This occurs, for example, by preventing the control pulses of the oscillator 8 from being produced whenever the output current or voltage of the converter 3 tends to increase above a desired value. Thus, the oscillator 8 and the switch 7, respectively, operate at a certain pulse rate until the voltage or current-5 comparator 9 or 10.11 stops the oscillator 8 for a short pulse break, during which the controlled switch 7 remains in the OFF state. Alternatively, the oscillator 8 may control the pulse ratio of the switch 7 by shortening the pulse duration as the current or voltage tends to increase above a desired value. The pulse frequency of the oscillator 8 is selected with respect to the size of the components L, C so that with normal load current 10 the pulse breaks are minimized, whereby the load of the switch 7 is optimal and the output voltage variation is small.

The load is switched on and off by ON / OFF control from the smart node 2 to the oscillator.

15

The converter 3 may be a separate component to be connected between the output terminal 4 of the intelligent node 2, whereby it may optionally be coupled to the nodes 2 from which power is provided to devices operating at an optional voltage. The converter 3 may also be constructed as an integral part of the output terminal 4.

Claims (10)

109846 An intelligent power distribution system powered by an optional output voltage comprising a cable (1) provided with power supply conductors (1a, 1b) and a smart node (2) having a controlled power switch (7) through which the power cable (1a) connects to the output terminal (2). 4) for supplying power to the load (5, 6) controlled by the intelligent node (2), characterized in that a converter (3) is connected between the output of the controlled switch (7) and the output terminal (4) with an output voltage level selectable by the controlled switch (7) ON / OFF with pulse timing control. 10 System according to claim 1, characterized in that the intelligent node (2) has an oscillator (8) which controls the ON / OFF pulse timing of the controlled switch (7) and a voltage comparator (9) which controls the operation of the oscillator (9). 3) by comparing the voltage measured at the output with the reference voltage 15 provided by the smart node (2) so as to obtain the desired output voltage of the converter. System according to Claim 2, characterized in that the smart node (2) has a current comparator (10, 11) which controls the operation of the oscillator (8) by comparing the current measured at the output of the converter (3) and: *; by comparing the output current so that the output current of the converter (3) does not exceed the desired: Y current limit. • * I • · System according to Claim 3, characterized in that the voltage commander γ ': 25 has a common ENABLE / DISABLE connection of the oscillator (9) and the current comparator (10, 11) which prevents the output pulses Y of the oscillator (8). : whenever the output voltage or current of the converter (8) tends to increase above the desired value. A system according to any one of claims 2 to 4, characterized in that. : the oscillator (8) and the correspondingly controlled switch (7) operate at a certain pulse ratio,. γ: until the voltage or current comparator (9; 10, 11) stops the oscillator (8) for a short pulse pause, during which the controlled switch (7) remains OFF. 109846 System according to one of Claims 2 to 4, characterized in that the oscillator (8) controls the pulse ratio of the controlled switch (7) by shortening the pulse duration as the output current or voltage of the converter (3) tends to increase above the desired value. 5 System according to one of Claims 1 to 6, characterized in that the output voltage levels of the converter (3) are arranged to be selected by the control provided by the smart node (2). System according to one of Claims 1 to 7, wherein the voltage between the power supply conductor (1a, 1b) is 42 V, characterized in that the output voltage of the converter (3) is selected to be 12 V or 24 V. System according to one of Claims 1 to 8, characterized in that the converter (3) is a separate device to be installed between the smart node (2) and the output terminal 4. System according to one of Claims 1 to 8, characterized in that the converter (3) is an integral part of the output terminal (4). • · • I · * * * »· · *» 7 109846