WO2013128354A1

WO2013128354A1 - Power distribution track system having separate ac and dc conductors, and power supply device converting ac to dc

Info

Publication number: WO2013128354A1
Application number: PCT/IB2013/051459
Authority: WO
Inventors: Adrianus Johannes Stephanus Maria De Vaan; Matthias Wendt; Rainer ZITZMANN; Egbert Lenderink; Haimin Tao
Original assignee: Koninklijke Philips N.V.
Priority date: 2012-03-02
Filing date: 2013-02-22
Publication date: 2013-09-06

Abstract

The invention relates to a power supply device (1) for being connected to a track (8) of a power distribution track system (4) for providing power to electrical loads (2) like lamps. The power supply device is adapted to be attached to the track such that it receives first power, preferentially AC power,from a first conductor (5) of the track, wherein the first power is converted to second power, preferentially DC power, and that the second power is provided to a second conductor (7) of the track. The attaching unit is preferentially adapted to allow the power supply device to be clicked on the track. Power supply devices of this kind can easily be distributed along the track as desired by an installer for supplying enough second power to the second conductor. The power distribution track system can therefore be installed in a relatively simple and fast way.

Description

POWER DISTRIBUTION TRACK SYSTEM HAVING SEPARATE AC AND DC CONDUCTORS, AND POWER SUPPLY DEVICE CONVERTING AC TO DC

FIELD OF THE INVENTION

The invention relates to a power supply device, a power distribution track system and a method for setting up the power distribution track system.

BACKGROUND OF THE INVENTION

Power distribution track systems for lighting fixtures, which provide a direct current (DC) network for supplying DC power to the lighting fixtures, generally comprise a track with several conductors, which is connected to a ceiling of a room. The conductors are electrically connected to DC power supplies at different locations above the ceiling and the lighting fixtures are attached to the track such that they are electrically connected to the conductors within the track, in order to provide the DC power to the lighting fixtures via the conductors of the track. Installing the power distribution track system with DC power supplies above the ceiling at different locations, wherein the DC power supplies have to be wired and wherein the wiring should be made invisible, is very complex and time consuming. SUMMARY OF THE INVENTION

It is an object of the present invention to provide a power supply device, which allows a person to easier install a power distribution track system. It is a further object of the present invention to provide a corresponding power distribution track system and a corresponding method for setting up the power distribution track system.

In a first aspect of the present invention a power supply device for being connected to a track of a power distribution track system for providing power to electrical loads is presented, wherein the track comprises a first conductor for supplying a first power and a second conductor for supplying a second power and wherein the power supply device comprises:

- a power converter for converting the first power to the second power, an attaching unit for attaching the power supply device to the track such that the first power is supplied to the power converter by the first conductor of the track for allowing the power converter to convert the supplied first power to the second power and such that the power converter provides the second power to the second conductor of the track.

Since the power supply device can be attached to the track of the power distribution track system such that the first power is supplied to the power converter by the first conductor of the track, wherein the second power resulting from the conversion is provided to the second conductor of the track, the second conductor of the track can be supplied with second power as required by electrical loads, which may also be attached to the track, relatively easily. Thus, a person can easily distribute corresponding power supply devices along the track as desired for supplying enough second power to the second conductor. The power distribution track system can therefore be installed in a relatively simple and fast way.

The first power is preferentially alternating current (AC) provided by a mains power source. The second power is preferentially DC power supplied to one or several electrical loads attached to the track. The electrical loads are preferentially lamps, but the electrical loads can also be other devices like sensors, user interfaces allowing a user to modify the supply of the second power to the one or several electrical loads attached to the track, et cetera. The power converter is preferentially an AC/DC power converter for converting AC power to DC power.

It is preferred that the attaching unit is adapted to allow the power supply device to be clicked on the track. Since the power supply device can be arranged at its position along the track simply by clicking the power supply device onto the track, the installation of the power distribution track system can be further simplified and the time needed for installing the power distribution track system can be further reduced.

In an embodiment the attaching unit is adapted to attach the power supply device to a frontal end of the track. In this embodiment the power supply device can be regarded as being an end feed for feeding the track with the second power.

Moreover, the power distribution track system can comprise several tracks comprising a first conductor for supplying the first power and a second conductor for supplying the second power, wherein the attaching unit can be adapted to attach the power supply device to at least two of the several tracks for connecting the at least two tracks such that the first power is supplied to the power converter by the first conductor of at least one of the at least two tracks and such that the power converter provides the second power to the second conductor of at least one of the at least two tracks. Preferentially, the attaching unit is adapted to attach the power supply device to the at least two tracks for connecting the at least two tracks such that the first power is supplied to the power converter by the first conductors of the at least two tracks and such that the power converter provides the second power to the second conductors of the at least two tracks. In this case the power supply device can be regarded as being a middle feed for feeding the tracks connected by the power supply device with second power. The middle feed can connect and feed, for instance, two or four tracks, wherein the middle feed is preferentially x-shaped or cross-shaped, if it feeds four tracks.

The power supply device can be adapted to electrically connect at least one of a) the first conductors of the at least two tracks for transposing the first power between the at least two tracks and b) the second conductors of the at least two tracks for transposing the second power between the at least two tracks. Moreover, the power converter comprises preferentially a printed circuit board, wherein the power supply device can be adapted such at least one of the first conductors of the at least two tracks and of the second conductors of the at least two tracks are electrically connected via the printed circuit board. For instance, connectors for connecting a first conductor or a second conductor can be soldered to the printed circuit board. The leads to an increased degree of integration of the different components of the power supply device and can therefore allow for a power supply device having a reduced size.

Moreover, on the printed circuit board relatively thick electrical conductors like copper stripes can be used for electrically connecting the first conductors and/or the second conductors of the different tracks. This allows the power supply device to carry relatively large currents from one track to another track.

Furthermore, the power supply device can be adapted such that the printed circuit board is at least partly located within the track, if the power supply device is attached to the track. Preferentially, the power supply device is adapted such that the printed circuit board is arranged between electrical conductors within the track, if the power supply device is attached to the track. For instance, the first conductor can comprise two sub conductors for guiding the first power and the second conductor can comprise two sub conductors for guiding the second power, wherein the power supply device can be adapted such that the printed circuit board is arranged between two sub conductors of at least one of the first and second conductors, if the power supply device is attached to the track.

Moreover, the track can comprise a carrying element for carrying the first and second electrical conductors, wherein the power supply device can comprise an outer casing being adapted such that, if the power supply device is attached to the track, a part of the outer casing is arranged between a part of the carrying element and a part of the printed circuit board. At least the part of the outer casing arranged between a part of the carrying element and a part of the printed circuit is preferentially made of an electrically insulating material like plastics for improving electric safety.

The power supply device can comprise an adaptation element allowing a user to adapt the power supply device to a desired number of tracks to which the second power is to be applied. For instance, the adaptation element can include an opening to wires to be cut off, if certain tracks should not receive the second power, or another means which provides an easy access to these wires. Or, the adaptation element can be provided by providing jumpers on a printed circuit board of the power supply device, wherein the jumpers are configured such that depending on the setting of the jumpers certain tracks are supplied with the second power. This allows an installer to decide, which tracks should be supplied with the second power, during the installation procedure, without having to provide many different kinds of power supply devices being adapted for supplying different amounts of tracks.

The attaching unit can comprise clamps for electrically connecting the power supply device to the first and second conductors, wherein the clamps can be adapted such that the respective conductor is clamped from two opposing sides. This increases the area of contact between the clamps and the respective conductor in comparison to clamps clamping the respective conductor from a single side only, thereby allowing a flow of relatively large currents through the power supply device.

It is further preferred that the power converter is adapted such that, if the power supply device is not fully loaded, the output voltage provided by the power supply device is equal to a nominal voltage of the power supply device. Thus, the power supply device can be output voltage controlled. It is also preferred that the power converter is adapted such that, if the power supply device delivers its maximum output current, the output voltage will be lowered for additionally drawn currents. Thus, if different power supply devices of this kind are connected in parallel, the power supply devices in the power distribution system will automatically share the total power.

In a preferred embodiment the track is attached to a plane surface, wherein the power supply device comprises an outer casing being adapted for allowing the power supply device to be attached to the track such the outer casing has dimensions in a direction being perpendicular to the track and parallel to the surface, which are similar to the dimensions of the track in this direction. For instance, the track, which may be a U-shaped track, in which the first and second conductors can be arranged, can have a width being similar to the width of the outer casing of the power supply device. Moreover, preferentially the outer casing of the power supply device and the track can also have the same color. This can reduce the visibility of the power supply device on the track.

The power supply device can further comprise an indication unit for providing an indication, if the provided second power is smaller than required by the power distribution track system. This allows indicating to a person, who installs the power distribution track system, whether an additional power supply device should be attached to the track.

In a further aspect of the present invention an electrical load for being connected to a track of a power distribution track system is presented, wherein the track comprises a first conductor for supplying a first power and a second conductor for supplying a second power and wherein the electrical load comprises:

an attaching unit for attaching the electrical load to the track such that the second power supplied by the second conductor of the track is provided to the electrical load for powering the electrical load,

a voltage determination unit for determining a voltage at the position of the electrical load on the track,

an indication unit for providing an indication depending on the determined voltage.

The voltage determination unit is preferentially adapted to measure the voltage on the second conductor at the position of the electrical load. The provided indication is preferentially a light indication, in particular, a light sequence. The indication unit comprises therefore preferentially a light source for providing indicator light.

The indication unit is preferentially adapted to provide a gradual indication depending on the determined voltage. In particular, the indication unit can be adapted to comprise assignments between voltages and indications and to provide an indication based on the determined voltage and the assignments. For instance, the voltage determination unit can be used to measure voltage drops being differences between a nominal voltage and an actually measured voltage, wherein based on the height of the respective voltage drop different indications like different numbers of light emitting diodes (LEDs) having certain colors can be shown. Thus, to different determined voltages, i. e. to different voltage drops, different indication light configurations defined by certain colors and certain numbers of emitting LEDs can be assigned, wherein based on the actually measured voltage and these assignments a corresponding indication light configuration can be shown as the provided indication. This allows a user like an installer to readily see at which electrical load an additional power supply device is most strongly needed. The indication unit can also be adapted to provide a certain indication light configuration, if the actually determined voltage and the nominal voltage are substantially the same, i. e. if a voltage drop is substantially not present, or if the voltage drop is smaller than a predefined threshold. For instance, in this case a green light may be shown as the indication.

In a further aspect of the present invention a power distribution track system for providing power to an electrical load is presented, wherein the power distribution track system comprises:

a track with a first conductor for distributing first power and with a second conductor for distributing second power,

- an electrical load attached to the track such that it is electrically connected with the second conductor,

a power supply device as defined in claim 1 attached to the track via the attaching unit such that the first power supplied by the first conductor of the track is converted by the power converter to the second power and that the second power is supplied to the second conductor of the track.

The power distribution track system may comprise a voltage determination unit for determining a voltage at a position on the track and an indication unit for providing an indication depending on the determined voltage. In an embodiment the electrical load comprises the voltage determination unit and the indication unit.

In a further aspect of the present invention a method for setting up a power distribution track system is presented, wherein the method comprises:

providing a track with a first conductor for distributing a first power and with a second conductor for distributing a second power,

attaching an electrical load to the track such that it is electrically connected with the second conductor,

attaching a power supply device as defined in claim 1 to the track such that the power converter of the power supply device receives the first power from the first conductor to be converted to the second power to be supplied to the second conductor.

It shall be understood that the power supply device of claim 1, the electrical load of claim 9, the power distribution track system of claim 12, and the method of claim 15 have similar and/or identical preferred embodiments, in particular, as defined in the dependent claims.

It shall be understood that a preferred embodiment of the invention can also be any combination of the dependent claims with the respective independent claim. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows schematically and exemplarily an embodiment of a power distribution track system,

Fig. 2 shows schematically and exemplarily an embodiment of a power supply device of the power distribution track system,

Fig. 3 shows schematically and exemplarily an output voltage of the power supply device depending on a load current,

Fig. 4 shows schematically and exemplarily an electrical load, which may be attached to the power distribution track system,

Fig. 5 shows exemplarily a table illustrating assignments between voltages and indication light configurations,

Fig. 6. shows exemplarily a table illustrating indication light configurations of different electrical loads arranged at different distances to the power supply device,

Fig. 7 shows schematically and exemplarily a perspective view of a track, power supply devices and lamps of a power distribution track system, Fig. 8 shows a flowchart exemplarily illustrating an embodiment of a

method for setting up a power distribution track system,

Fig. 9 shows schematically and exemplarily a further embodiment of a

power distribution track system,

Fig. 10 shows schematically and exemplarily a middle feed of the power distribution track system shown in Fig. 9,

Fig. 11 shows schematically and exemplarily an end feed of the power

distribution track system shown in Fig. 9,

Fig. 12 shows schematically and exemplarily a further embodiment of a

power distribution track system,

Fig. 13 shows schematically and exemplarily a middle feed of the power distribution track system shown in Fig. 12,

Fig. 14 shows schematically and exemplarily a perspective view on an end of an embodiment of a track of a power distribution track system, and 15 and 16 show schematically and exemplarily different views of a

connection configuration for connecting a feed of a power distribution track system to a track of the power distribution track system. DETAILED DESCRIPTION OF EMBODIMENTS

Fig. 1 shows schematically and exemplarily an embodiment of a power distribution track system for providing power to an electrical load. The power distribution track system 4 comprises a track 8, which may also be regarded as being a bus bar component, with a first conductor 5 for distributing first power and with a second conductor 7 for distributing second power. The first and second conductors may be regarded as being bus bar conductors. In this embodiment the first power is AC power supplied by a mains power source 3 and the second power is DC power. The power distribution track system 4 further comprises several electrical loads 2 attached to the track 8 such that they are electrically connected to the second conductor 7 for supplying the DC power to the electrical loads 2. The power distribution track system 4 further comprises a power supply device 1 attached to the track 8, which is adapted to convert the AC power from the first conductor 5 to the DC power supplied to the second conductor 7. The power supply device can also be regarded as being a power supply module. The power distribution track system 4 also comprises a control unit 9 for controlling the electrical loads 2 and optionally also the power supply device 1 via a third conductor 6.

Fig. 2 shows schematically and exemplarily the power supply device 1 in more detail. The power supply device 1 comprises a power converter 12 for converting the AC power to the DC power. The power converter is therefore an AC/DC power converter. The power supply device 1 further comprises an attaching unit 11 for attaching the power supply device 1 to the track 8 such that the AC power is supplied to the power converter 12 by the first conductor 5 of the track 8 for allowing the power converter 12 to convert the supplied AC power to the DC power and such that the power converter 12 provides the DC power to the second conductor 7 of the track 8. The attaching unit 11 is adapted to allow the power supply device 1 to be clicked on the track 8. In particular, the track 8 is substantially U- shaped as schematically and exemplarily shown in Fig. 7, wherein the track 8 can be attached to a ceiling of a room such that the opening of the substantially U-shaped track 8 is directed towards the floor of the room. The attaching unit 11 is preferentially adapted such that the power supply device 1 can be clicked into this bottom opening of the track 8. Electrical contacts of the power supply device 1 are configured such that they contact the first conductor 5 and the second conductor 7, respectively, if the power supply device 1 is clicked into the bottom opening of the track 8.

The power supply device comprises an outer casing 10 which in the exemplary perspective view shown in Fig. 7 protrudes over the width of the track 8. In other

embodiments, the outer casing can also have another shape. For instance, the outer casing can have dimensions in a direction being perpendicular to the track 8 and parallel to the ceiling, which are similar to the dimensions of the track 8 in this direction, i.e. the width of the outer casing 10 can be similar to the width of the track 8. The track 8 and the outer casing 10 can also have the same color, in order to reduce the visibility of the power supply device on the track.

In the power distribution track system one or several power supply devices 1 and one or several electrical loads 2 can be attached to the track 8. For instance, one power supply device 1 and three electrical loads 2 as exemplarily shown in Fig. 1, two power supply devices 1 and four electrical loads 2 as exemplarily shown in Fig. 7 or another number of power supply devices and electrical loads can be attached to the track. The electrical loads may be regarded as being peripherals like luminaires.

The power converter 12 is preferentially adapted such that, if the power supply device is not fully loaded, the output voltage provided by the power supply device 1 is equal to a nominal voltage of the power supply device 1. Thus, the power supply device 1 is preferentially output voltage controlled. Moreover, the power converter 12 is preferentially adapted such that, if the power supply device 1 delivers its maximum output current, the output voltage will be lowered for additionally drawn currents. For instance, the power converter can be adapted to sense the output current and can comprise an output voltage feedback control loop, wherein the output current can be related to the output voltage by adding the sensed output current to the output voltage feedback control loop such that the output voltage will be lowered for the additionally drawn currents. If in an embodiment several power supply devices are electrically connected in parallel to the track 8, this leads to an automatic sharing of the total power among the power supply devices attached to the track 8. The rate of the voltage drop for additionally drawn currents can depend on the capacity of the power converter. In particular, the larger the capacity, i. e. the higher the wattage, the slower may be the drop rate.

The power converter can be adapted to, for instance, lower the output voltage by 0.5 percent at 20 percent of the maximum load, by 1 percent at 40 percent of the maximum load, by 1.5 percent at 60 percent of the maximum load, by 2 percent at 80 percent of the maximum load, and then the output voltage drop can linearly increase to 4 percent at 100 percent of the maximum load. The power converter may be adapted to accept an overload of, for instance, 10 percent such that at a load of 110 percent of the maximum load the output voltage may be reduced by 10 percent. For larger loads the power converter may be switched off. Thus, if in an example the nominal voltage of the power converter is 50 V and the maximum current is 2 A, at a load of 0.8 A, i.e. at 40 percent of the maximal load, the output voltage will be 49.5 V which corresponds to a voltage drop of 1 percent, at a load of 1.6 A, i.e. at 80 percent of the maximal load, the output voltage will be 49 V which corresponds to a voltage drop of 2 percent, and at a load of 2 A, i.e. at the maximal load, the output voltage will be 48 V which corresponds to an output voltage drop of 4 percent. If the power converter gets overloaded to 2.2 A, i. e. overloaded by 10 percent, the output voltage will be 45 V, i. e. the voltage drop will be 10 percent. Fig. 3 shows schematically and exemplarily a corresponding characteristic 30, wherein the output voltage U is shown in V depending on the current / in A.

Fig. 4 shows schematically and exemplarily more details of an electrical load 2 attached to the track 8. The electrical load 2 comprises an attaching unit 15 for attaching the electrical load 2 to the track 8 such that the DC power supplied by the second conductor 7 of the track 8 is provided to the electrical load 2 for powering the same. Also the attaching unit 15 can be adapted to allow a user to click the electrical load 2 into the bottom opening of the substantially U-shaped track 8. Electrical connections of the electrical load 2 are adapted such that they contact the second conductor 7, if the electrical load 2 is attached to the track 8 via the attaching unit 15.

The electrical load 2 is preferentially a lamp. However, the electrical load 2 can also be another electrical device like an electrical sensor for, for instance, detecting whether persons are within the room, measuring the ambient light intensity, et cetera. Such a sensor may be connected to the control unit 9, in order to allow the control unit 9 to control the electrical loads 2 and the power supply device 1 depending on the sensing result.

The control unit 9 can be adapted to control a lamp such that it can dim the lamp and/or it can change the color, in particular, the color temperature, of the light emitted by the lamp. The control unit 9 can be adapted to allow a user via a user interface comprising, for instance, a slidable element or a rotatable element, to control the lamp, for instance, to dim the lamp and/or to change the color of the lamp. Moreover, the control unit 9 can be adapted to gather operation and maintenance information of the lamps. The electrical load 2 further comprises a lamp driver 16 and a light source 17, wherein the lamp driver 16 is supplied by the DC power from the second conductor 7 and drives the light source 17. Moreover, the electrical load 2 comprises a voltage determination unit 18 for determining a voltage at the position of the electrical load 2 on the second conductor 7 and an indication unit 19 for providing an indication depending on the determined voltage.

The indication unit preferentially comprises one or several indicator light sources being, in this embodiment, LEDs, for indicating whether an electrical load is supplied with too low DC power, wherein the indicator light can be a light sequence.

In particular, the indication unit 19 is adapted to provide a gradual indication depending on the determined voltage, wherein assignments between voltages and indications are used. In this embodiment, the indications are indication light configuration provided by the LEDs of the indication unit 19. The assignments are therefore assignments between possible voltages at the position of the respective electrical load and corresponding indication light configurations. Fig. 5 shows schematically and exemplarily such assignments.

In Fig. 5 the assignments are shown in a table 31, wherein a first column 32 comprises voltages and a second column 33 comprises indication light configurations. In this example the indication unit 19 comprises six LEDs, a first group of three red LEDs 34, a second group of two yellow LEDs 35 and a green LED 36. Depending on the voltage determined by the voltage determination unit 18 the electrical load 2 shows the respective indication light configuration as shown in Fig. 5.

The voltage measured by the voltage determination unit of the respective electrical load may not only be smaller than a nominal voltage because a power supply device supplies a reduced output voltage, but also because of an additional voltage drop caused by the second conductor. This additional voltage drop depends on the distance of the respective electrical load to the respective power supply device, i. e. an electrical load having a larger distance to the power supply device will determine a voltage being smaller than a voltage determined by an electrical load which is located closer to the power supply device. Thus, the indications provided by the indication units of different electrical loads can be different at the same total load condition due to different distances of the electrical loads to the power supply device. The different indication light configurations for different distances of the different electrical loads to the power supply device are exemplarily illustrated in Fig. 6. Fig. 6 shows a table 40, wherein a first column 41 comprises exemplary voltages measured by a first electrical load having a distance of 5 m to a power supply device, a second column 42 comprises the indication light configurations for the different voltages shown in the first column 41, a third column 43 exemplarily shows voltages measured by a second electrical load having a distance of 10 m to the power supply device, and a fourth column 44 shows indication light configurations of the second electrical load. In Fig. 6 it is assumed that the voltages in the first and third columns, which are in the same row, are measured at the same total load condition. Thus, for instance, if the first electrical load measures, in this example, the voltage of 47 V, the second electrical load measures a voltage of 46 V. Since different voltages are measured by the different electrical loads at the same total load condition, also the indication light configuration provided by the LEDs of the indication unit of the respective electrical load are different as shown in Fig. 6. A user like an installer can therefore see which electrical load needs more additional power than other electrical loads, wherein the user can attach and distribute one or more additional power supply devices to the track based on this information. Also the power supply device 1 can comprise an indication unit 14 for indicating that a further power supply device is needed.

Alternatively or in addition, the power distribution track system can comprise a resistive control line, wherein at a first position the resistive control line is connected to the power supply device, at a second position the resistive control line is connected to ground, and at one or several third positions between the first and second positions the resistive control line can be connected to one or several electrical loads, respectively. The voltage determination unit of the respective electrical load can be adapted to measure the voltage on the resistive control line at the respective third position on the second conductor, wherein the indication unit of the respective electrical load can be adapted to provide an indication depending on the measured voltage, for instance, as described above with reference to Figs. 4 to 6. The resistive control line can be formed by the track, especially by a resistive coating on the track. Alternatively, the track can comprise an additional resistive wire as the resistive control line.

In the following an embodiment of a method for setting up a power distribution track system will exemplarily be described with reference to a flowchart shown in Fig. 8.

In step 101 a track with a first conductor for distributing a first power, in particular, AC power, and with a second conductor for distributing a second power, in particular, for distributing DC power, is provided. In step 102 the track is attached to, for instance, a ceiling of a room and the first conductor is electrically connected with a mains power source. In step 103 one or several electrical loads are attached to the track such that they are electrically connected with the second conductor for supplying the one or electrical loads with the second power, in particular, the DC power. In step 104, one or several power supply devices are attached to the track such that the power converters of the power supply devices receive the first power from the first conductor to be converted to the second power to be supplied to the second conductor. Step 104 can also be performed before step 103. Moreover, these steps can be performed several times and intermittently, i.e., for instance, several power supply devices and electrical loads can be intermittently attached to the track, wherein, in particular, if it is indicated that the DC power is too low, one or more further power supply devices can be attached to the track.

The first, second and third conductors are preferentially metallic conductors, especially copper conductors. In particular, the power distribution track system described above with reference to Figs. 1 to 7 integrates conductors for AC power with conductors for control and with conductors for DC power distribution. Since the AC power is distributed over the length of the track, the connection to the AC mains power source to the track can be at any position on the track, substantially independently of the position of the power supply devices. The power supply devices connect to the AC mains rail, i.e. to the first conductor, and output the DC link voltage, i.e. the DC power, to the DC rail, i.e. to the second conductor. A connection to the control lines may be used or not dependent on the control functionality provided by the control unit.

The electrical loads are preferentially lamp devices having only contacts to the DC conductor and the control conductor, i.e. to the second and third conductors.

Preferentially, a lamp driver converts the DC link voltage to a lamp drive current as required by a light source of the respective lamp device. Lamp parameters like the light intensity and/or the light color may be controlled by the control unit via the control conductors, i.e. via the control link.

If the lamp devices are redistributed on the track, there may be a misbalance between DC power supply devices and the number of lamp devices on a particular track and situations may occur where a power supply device has an overload, because too many lamp devices are on the rail, i.e. track, served by the respective power supply device, while another power supply device may serve a rail having no lamp devices at all. If the power limit of a power supply device gets overloaded, the whole power supply device may switch off, resulting in undesired effects. The power supply device described above with reference to Figs. 1 and 2 is therefore a building block having an AC/DC conversion means, i.e. a power converter, wherein the building block can be clicked on the rail, i.e. on the track. An installer may use several of these power supply devices and spread them over the full track. This can also solve a problem of high currents in the DC conductors as a power supply device can be near to a group of lamps.

The track may contain a number of copper leads forming the different conductors, two copper leads connected to the mains AC voltage forming the first conductor, two copper leads for distributing the DC voltage forming the second conductor and one or more further copper leads forming the third conductor for controlling purposes. The track can also contain more copper leads, for example, further supply leads for supplying, for instance, a voltage of 5 V.

Each power supply device has preferentially a connector to the track, which hooks up the power supply to the AC mains leads and to supply the DC power from each power supply device to the DC leads in the track.

An installer, in particular, an end user, may simply attach all lamp devices to the track and distribute the power supply devices over the length of the track in a way that there is always one power supply device nearby, for instance, every three lamp devices. If the installer observes a power supply issue in the power distribution track system, the installer can simply hook up another power supply device in the vicinity of the lamp device that delivers the most problems. The system may incorporate indicators like red light indicators that light up at lamp fixtures, i.e. lamp devices, when the power to that lamp is insufficient, in order to indicate to the installer that the installer needs to click on a power supply device nearby that lamp or that the installer needs to move another power supply device closer to that particular lamp.

Since the lamps are powered via DC leads from the track, the voltage at the lamp will drop at higher currents when the lamp unit is further away from a power supply device. For example, the nominal voltage on the DC leads, i.e. on the second conductor, can be 48 V or 50 V. The DC voltage at the input of the respective electrical load will be slightly lower than the nominal voltage due to the voltage drop along the DC conductor when it carries a current. Therefore, the electrical load can be adapted to sense the voltage at the physical point where the respective electrical load is connected to the track, wherein the sensed voltage can be used as an indicator. If the voltage sensed by the respective electrical load is much lower than the nominal voltage, the track, i.e. the second conductor, is heavily loaded and extra power supply devices are needed. Otherwise, if the voltage is close to the nominal voltage, there is abundant power available from the power supply device and additional power supply devices are not needed. Thus, by comparing the measured voltage with a predefined voltage threshold, it can be determined whether an additional power supply device is needed or not, wherein, if an additional power supply device is needed, this can be shown by an indication unit of, for instance, the respective electrical load. The voltage drop, i.e. the power drop, can therefore be used as an indicator to notice whether a power supply device needs to be moved closer to the respective electrical load or whether an additional power supply device should be hooked up to the system.

Moreover, a resistive control line can be used formed by, for example, the DC lead wires of the second conductor, especially after a small amount of resistance has been implemented in the DC lead wires, by the track itself, by a resistive coating on the track, by an additional resistive wire, et cetera. The resistive control line can also be used to determine whether an electrical load is supplied with sufficient power or not.

The respective electrical load can be adapted to measure the voltage at the physical position at which the respective electrical load is connected to the resistive control line, wherein the measured voltage can be used to determine whether the power supply to the respective electrical load.

Since the power supply devices can be clicked onto the rail, i.e. onto the track, the power distribution track system can be set up and modified very easily and fast. The power distribution track system is preferentially adapted to be a rail-oriented lighting system especially for retail.

The power supply devices may be hooked up to the track system using a track system connector, wherein the power supply device distracts its main power being the first power from the track, converts the main power to a supply power being the second power, and delivers the supply power back to the track via the same track connector. The track preferentially serves as an illumination system, wherein the power supply devices are preferentially encased in an encasing having the same dimension as the track. Additional intelligence with indicators may be added, in order to indicate where additional power supplies are required on the track. The indicator may be an indicator light, in particular, a light sequence emitted by a lamp device. The indicator can be provided on the lamp devices, on the power supply device, or on another element of the power distribution track system. The lamp devices or other electrical loads on the track can be equipped with a system that measures voltage drops over the DC lead wires forming preferentially the first conductor. The measured voltage drops can be used to indicate the need of a closer or extra power supply nearby the respective lamp device.

Fig. 9 shows schematically and exemplarily a further embodiment of a power distribution track system for providing power to an electrical load. In this embodiment the power distribution track system 104 comprises tracks 8 with a first conductor for distributing first power and with a second conductor for distributing second power. The tracks 8 can be similar to the track described above with reference to, for instance, Fig. 1. Several electrical loads 2 are attached to the tracks 8 such that they are electrically connected with the second conductor. They are preferentially lamps or other electrical consumers like sensors, loudspeakers, et cetera. Power supply devices 101, 150 are attached to the tracks 8 such that the first power supplied by the first conductor of the tracks 8 is converted by a power converter of the respective power supply device 101, 150 to the second power and that the second power is supplied to the second conductor of the tracks 8.

The first power is also in this embodiment AC power supplied by a mains power source 3 and the second power is DC power. Moreover, also in this embodiment the power distribution track system 104 comprises a control unit 9 for controlling the electrical loads 2 and optionally also the power supply devices 101, 150 via a third conductor.

Figs. 10 and 11 show the power supply devices 101, 150 in more detail.

The power supply device 101 schematically and exemplarily shown in Fig. 10 can be regarded as being a middle feed for feeding the tracks 8 connected by the power supply device 101 with the second power. The power supply device 101 comprises a power converter 112 for converting the AC power to the DC power. The power converter 112 is therefore an AC/DC power converter. The power supply device 101 further comprises attaching units 111 for attaching the power supply device 101 to the tracks 8 to be connected such that the power converter 112 can convert the supplied AC power to the DC power and provide the DC power to the second conductor of the connected tracks 8. The attaching units 111 are preferentially adapted to allow the power supply device 101 to be partly moved and introduced into an open frontal end of the respective track 8. In particular, also in this embodiment the track 8 is substantially U-shaped as schematically and exemplarily shown in Fig. 7, wherein the attaching units 111 are preferentially adapted such that the power supply device 101 can be partly introduced and moved into an open frontal end of the respective track 8, whereby electrical contacts of the power supply device 101 contact the first conductor and the second conductor, respectively. The power supply device 101 is adapted to electrically connect the first conductors of the two connected tracks 8 for transposing the first power between the two connected tracks 8 and the second conductors of the connected two tracks 8 for transposing the second power between the two connected tracks 8. Moreover, the power converter 112 preferentially comprises a printed circuit board, wherein the power supply device 101 is preferentially adapted such that the first conductors of the two tracks 8 and the second conductors of the two tracks 8 are electrically connected via the printed circuit board. For instance, connectors for connecting a first conductor and connectors for connecting a second conductor can be soldered to the printed circuit board. This leads to an increased degree of integration of the different components of the power supply device 101 and can therefore allow for a power supply device having a reduced size. Moreover, on the printed circuit board relatively thick electrical conductors like copper stripes are preferentially used for electrically connecting the first conductors and the second conductors, respectively, of the different connected tracks, in order to allow the power supply device 101 to carry relatively large currents from one track to the other.

The further power supply device 150 schematically and exemplarily shown in Fig. 11 can be regarded as being an end feed for feeding the respective track 8 with the second power. The end feed 150 comprises a power converter 152 for converting AC power supplied by the first conductor of the track 8 to DC power to be provided to the second conductor of the track 8. Moreover, the power supply device 150 comprises an attaching unit 151 for attaching the power supply device 150 to an open frontal end of the track 8. In contrast to the power supply device 101 schematically and exemplarily shown in Fig. 10, which may be regarded as being a middle feed, the end feed 150 schematically and exemplarily shown in Fig. 11 is adapted to be just attached to the open frontal end of a single track 8, without connecting two different tracks 8 of the DC power distribution track system. Also in this embodiment the attaching unit is preferentially adapted to allow the power supply device 150 to be partly introduced and moved into the open end of the track 8 such that electrical contacts of the power supply device 150 contact the first conductor and second conductor, respectively, of the track 8, in order to allow the power converter 152 to receive AC power from the first conductor and to provide DC power to the second conductor.

Fig. 12 shows schematically and exemplarily a further embodiment of a DC power distribution track system for providing power to an electrical load. Fig. 12 is a schematical top view showing a schematical view onto the power distribution track system 204 from above. Also in this embodiment the power distribution track system 204 comprises several tracks 8 with a first conductor for distributing first power being AC power and with a second conductor for distributing second power being DC power. The AC power is supplied by a mains power source 3. The power distribution track system 204 further comprises several electrical loads 2 attached to the respective track 8 such that they are electrically connected to the second conductor for supplying the DC power to the electrical loads 2. The power distribution track system 204 also comprises a power supply device 201 attached to the tracks 8, which is adapted to convert the AC power from the first conductor to the DC power to be provided to the second conductor. The power distribution track system 204 further comprises a control unit 9 for controlling the electrical loads 2 and optionally also the power supply device 201 via a third conductor.

Fig. 13 shows schematically and exemplarily the power supply device 201 in more detail. The power supply device 201 comprises a power converter 212 for converting the AC power to the DC power. Also in this embodiment the power converter is therefore an AC/DC power converter. The power supply device 201 further comprises four attaching units 211 for attaching the power supply device 201 to four tracks 8 such that the AC power is supplied to the power converter 212 by the first conductor of at least one of the four tracks 8 for allowing the power converter 212 to convert the supplied AC power to the DC power and such that the power converter 212 provides the DC power to the second conductors of the four tracks 8. The attaching units 211 are adapted to allow the power supply device 201 to be partly moved and introduced into the open frontal ends of the tracks 8 such that electrical contacts of the power supply device 201 contact the first conductor and the second conductor, respectively, of the different tracks 8. The power supply device 201 is substantially X-shaped or cross-shaped, in order to connect the four tracks 8 in an X-like or cross-like, respectively, configuration. Since the power supply device 201 connects several tracks 8 such that it is arranged in between the tracks 8, the power supply device 201 can be regarded as being a middle feed feeding the connected tracks 8 with DC power.

Also the power supply device 201 is adapted to electrically connect the first conductors of the different tracks 8 connected by the power supply device 201 for

transposing the first power between the different tracks and the second conductors of the different tracks for transposing the second power between the different tracks via a printed circuit board of the power converter. For instance, also in this embodiment connectors for connecting a first conductor and a second conductor to the power supply device can be soldered to the printed circuit board. Furthermore, also in this embodiment on the printed circuit board relatively thick electrical conductors like copper stripes can be used for electrically connecting the first conductors and the second conductors, respectively, of the different tracks.

The power supply device 201 further comprises an adaptation element 260 allowing a user to adapt the power supply device 201 to a desired number of tracks 8 to which the second power is to be supplied. For instance, the adaptation element 260 can include an opening to wires to be cut off, if certain tracks should not receive the second power, or it can include another means which provides an easy access to these wires. Or, the adaptation element 260 can be adapted to provide jumpers on the printed circuit board of the power supply device, wherein the jumpers can be configured such that depending on the setting of the jumpers certain tracks are supplied with the second power. This allows an installer to decide, which tracks should be supplied with the second power, during the installation procedure, without having to provide many different kinds of power supply devices being adapted for supplying different numbers of tracks. For instance, the installer can deactivate the electrical connections to one of the four attaching units 211, in order to connect three tracks 8 via the power supply device 201.

The tracks preferentially further comprise, as already mentioned above, third conductors for control purposes, wherein the control unit 9 can be adapted to control the electrical loads 2 and optionally also the different power supply devices via the third conductor. Correspondingly, the attaching units of the power supply devices can optionally be further adapted such that the power supply devices are also electrically connected to the respective third conductor for receiving and/or transposing control signals from the control unit 9 via the third conductor. However, control signals can also be transmitted via other means. For instance, the control unit and the electrical loads and optionally also the power supply devices can be adapted such that the control signals are wirelessly transmitted using, for instance, Zigbee. In the latter case, the respective track may not comprise the third conductor for communication purposes.

Fig. 14 shows schematically and exemplarily a perspective view of a frontal end of a track 308, which may also be used in the above described DC power distribution systems. The track 308 comprises a carrying element 380 for carrying the first and second electrical conductors. The carrying element 380 is substantially U-shaped and comprises four copper conductors 381...384, of which only three copper conductors 381...383 can be seen in Fig. 14 for perspective reasons. The copper conductors 381...384 are held in isolating holding elements 385. The copper conductors 381...384 comprise ends being bent by 90 degrees such that the ends protrude into the inner space of the track 380. The attaching units 111, 151, 211 are preferentially adapted such that they enclose these protruding ends for electrically connecting the respective power supply device to the respective track 308. The copper conductors 381, 382 can be regarded as being sub conductors of the first conductor for providing the AC power and the further copper conductors 383, 384 can be regarded as being sub conductors of the second conductor of the track 308 for distributing the DC power. The tracks 8 described above with reference to Figs. 1, 2, 4, 7 and 9 to 13 can be similar to the track 308 exemplarily and schematically shown in Fig. 14, wherein optionally in addition a third conductor for communication purposes can be provided.

Figs. 15 and 16 schematically and exemplarily show how the attaching units of an end feed 150 and of a middle feed 101, 201 can be configured, wherein Figs. 15 and 16 show different views of the same configuration.

Fig. 15 shows schematically and exemplarily a view parallel to the longitudinal direction of the respective track element and Fig. 16 shows schematically and exemplarily a view along a transversal direction with respect to the respective track.

Fig. 15 shows schematically and exemplarily an attaching unit of the respective power supply device for being attached to the track 308, wherein the power supply device is partly moved and introduced into the track 308. The power supply device comprises a printed circuit board 387 comprising the different components of the respective power converter and optionally possible further components like transmission components for transmitting and receiving signals, control components like a microcontroller, et cetera. On the printed circuit board 387 copper stripes 370, 371 are provided, which are relatively thick, in order to allow them to carry relatively large currents. The printed circuit board is arranged within a casing 389 being adapted such that, if the power supply device is attached to the track 308, a part of the casing 389 is arranged between a part of the carrying element 380 and a part of the printed circuit board 387 as can be seen in Fig. 16. The casing 389 is made of an electrically insulating material like plastics for improving electric safety. The printed circuit board 387 is partly located within the track 308, after the power supply device has been attached to the track 308. In particular, the printed circuit board 387 is arranged between the electrical conductors 381...384, for instance, the printed circuit board 387 is arranged between the two sub conductors 381, 382 of the first conductor and the two sub conductors 383, 384 of the second conductor.

The attaching unit further comprises clamps 372, 374 for electrically connecting the power supply device to the first and second conductors 381...384, wherein the clamps 372, 373 are adapted such that the respective conductor is clamped from two opposing sides. This increases the area of contact between the clamps 372, 373 and the respective conductor 381...384 in comparison to clamps clamping a respective conductor from a single side only, thereby allowing a flow of relatively large currents through the power supply device. The attaching unit further comprises a sliding element 386 arranged at an end of the printed circuit board 387, wherein the sliding element 386 corresponds to a mating sliding element 390 of the track 380 such that the attaching unit can be slid into the respective open frontal end of the track guided by the sliding connection 386, 390.

It should be noted that, after the track in the respective power supply device has been installed, the longitudinal opening within the track is directed downwards and away from the ceiling, to which the respective track is preferentially attached. Thus, after installation the upper parts of the elements shown in Figs. 14 to 16 are preferentially lower parts of these elements. Moreover, in Fig. 15 only two clamps 372, 373 can be seen, although in this embodiment four clamps are present as schematically shown in Fig. 16.

The above described middle feeds and end feeds can be assembled in a fast and easy way to the one or several rails, i.e. to the one or several tracks, and contain power converters. They are preferentially operated in parallel. In the middle feeds power lines, i.e. corresponding electrical conductors, preferentially transpose mains current from one rail to the other and might also transpose DC current from one rail to the other one, while the power converter in such a middle feed preferentially simultaneously adds DC power to the system.

The current from a middle feed or an end feed to the system might flow to multiple lamps, meaning that the current from a middle feed or an end feed to the system might be much higher than a current flowing from the rail to a lamp. For that reason the power lines, i.e. the electrical conductors, in the middle feed and the end feed, respectively, and the electrical connectors from the middle feed and the end feed, respectively, to the lines should be able to handle relatively high currents. For instance, the electrical connectors in the middle feed and in the end feed should be adapted such that they provide a larger contact area in comparison to the contact areas between the respective electrical load and the respective rail.

Each connector of the attaching units of the end and middle feeds preferentially has a number of springs forming the clamps, wherein, if the respective connector is inserted into the respective rail, the spring is pushed over the copper conductors being preferentially copper wires. To allow high current, the connection surface between the springs, in particular, the copper of the springs if the springs are copper springs, and the copper of the copper conductor of the rail is preferentially relatively large. This large connection surface can be provided by clamps that connect to the copper conductors from the top and from the bottom. This is in contrast to electrical loads like lamps that are "mobile" on the track which may connect to the copper conductors from a single side only. Within a middle feed springs at an end may be copper wired to springs at another end of the middle feed. If the connector is shifted inside the rail, i.e. inside the track, the wires are preferentially embodied with insulating material for guaranteeing electric safety of the system. Copper wires inside the middle feeds are preferentially relatively thick, in order to handle relatively high currents such that these copper wires may consume a relatively large part of the volume. For instance, the copper wires may have a cross section of about 4 mm².

In above described embodiments AC/DC conversion means are formed as one or more building blocks integrated in end feeds or middle feeds of the rail system. The power lines, i.e. the electrical conductors, from the respective track are connected to the feeds using connectors. In the middle feeds each end of the feed is wired to a connector at the other end. To gain form factor, the connectors at each end of the respective middle feed are

preferentially interfaced via the printed circuit board of the respective AC/DC conversion means. For that reason springs of the connectors are preferentially soldered to the printed circuit boards of the power converters. All power lines between the tracks are then preferentially fed via thick copper stripes on the printed circuit boards of the power supply devices that are positioned within the respective feed. To obtain a favorable form factor it is preferentially further preferred that the printed circuit boards of the power supply devices become part of the respective connector to the electrical conductors of the respective track such that, within an installed system, the printed circuit board of the power supply device becomes already positioned partly within the rail of the power distribution track system being preferentially a track lighting system.

In an embodiment, an installer might choose during installation how he/she wants to feed the DC power of the power supply devices to the tracks, i.e. in such a way that the DC power of a power supply device is fed to multiple sides of a feed or only to a single side such that the power supply device is serving a single track only. This choice may be made by the installer in a simple way, for instance, by adjusting jumpers on the printed circuit board or by cutting off one or more connection wires from the power supply device.

Preferentially, the respective power converter is built on a printed circuit board that is partly positioned in the center of the respective rail, i.e. of the respective track, in a way such that a part of the printed circuit board is between copper wires forming the electrical conductors of the rail. The power supply device, in particular, the power converter, is preferentially surrounded by a plastic encasing, i.e. the outer casing, that moves partly between the rail to guarantee electric safety between the printed circuit board and the rail. At one end of the printed circuit board, in particular, at the top end of the printed circuit board in an installed configuration, there is preferentially a plastic slider, i.e., for instance, the sliding element 386, that moves in the respective rail, in particular, in a corresponding sliding element of the rail, which is preferentially arranged at the inner top part of the respective rail, when the rail is installed at a ceiling of a room.

Connectors in a feed are shown, for instance, in Figs. 15 and 16. Preferentially, copper wires within the track are bent at the end of the respective track by about 90 degrees, in order to enable the pins formed by the bent ends of the copper wires to glide into springs of the connectors. The springs of the connectors are preferentially directly soldered to the printed circuit board of the power supply device. These springs may be soldered to a thick copper layer on the printed circuit board, wherein these springs are connected via these thick copper layers to another end of the printed circuit board, where similar connectors are present to connect the power supply device to a next track.

The power supply device being an end feed or a middle feed can be regarded as being a power supply unit integrated within the respective feed. The respective feed may contain at least two connectors for connecting the respective feed to a track of the power distribution track system. The connectors of the respective feed to the power distribution track system may be directly soldered to the printed circuit board of the power supply device, in particular, of the power converter. The printed circuit board of the power supply device may be a part of the connector, and the printed circuit board of the power supply device may be positioned partly inside the respective track of the power distribution track system after installation.

Although in the embodiments described above with reference to Figs. 14 to 16 the attaching unit, in particular, the connectors, are adapted to attach sub conductors of the first electrical conductor and the second electrical conductor of the respective track only, the attaching unit can also be adapted to provide connectors for possible further electrical conductors of the track like a third electrical conductor for communication purposes.

Moreover, also the attaching unit described above with reference to Figs. 9 to 16 can be adapted to allow the respective power supply device, i.e. the respective feed, to be clicked to the track.

The power distribution track system can comprise a single track or several tracks, wherein to each track one or several power supply devices and one or several electrical loads can be attached. The several tracks can be electrically connected to or electrically insulated from each other.

Although in above described embodiments the electrical loads are preferentially lamps, the electrical loads can also be other electrical devices like sensors, loudspeakers, displays, et cetera.

The different units of the power distribution track system like the power supply devices, the electrical loads, the control unit, et cetera can comprise controllers, in particular, microcontrollers or other elements for performing the different functions described above like comparisons with predefined thresholds, controlling the intensity or the color of light emitted by a light source, controlling an indication unit for providing an indication, et cetera. Moreover, for performing the described measurements like the voltage measurements the respective unit of the power distribution track system like the respective electrical load comprises corresponding measuring elements.

Although in the above described embodiments the different functions like the comparison of a measured value with a threshold, the determination of an indication light configuration, et cetera are performed by certain units of the power distribution track system, these functions can also be performed by other units of the power distribution track system. For instance, functions described above as being performed by a respective electrical load can be performed by the control unit, after required information has been provided to the control unit, for example, via the control line.

Although in above described embodiment the first power is AC power, in other embodiments the first power can also be DC power, wherein the power converter can be adapted to convert the first DC power to second DC power to be used by the power distribution track system. The first DC power may be obtained from natural electricity sources, which may be attached to a building, like solar energy sources.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

A single unit or device may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

The invention relates to a power supply device for being connected to a track of a power distribution track system for providing power to electrical loads like lamps. The power supply device is adapted to be attached to the track such that it receives first power, preferentially AC power, from a first conductor of the track, wherein the first power is converted to second power, preferentially DC power, and that the second power is provided to a second conductor of the track. The attaching unit is preferentially adapted to allow the power supply device to be clicked on the track. Power supply devices of this kind can easily be distributed along the track as desired by an installer for supplying enough second power to the second conductor. The power distribution track system can therefore be installed in a relatively simple and fast way.

Claims

CLAIMS:

1. A power supply device for being connected to a track of a power distribution track system for providing power to electrical loads, the track (8; 308) comprising a first conductor (5; 381 , 382) for supplying a first power and a second conductor (7; 383, 384) for supplying a second power, the power supply device (1; 101; 150; 201) comprising:

a power converter (12) for converting the first power to the second power, an attaching unit (11; 111; 151; 211) for attaching the power supply device ( 1 ; 101; 150; 201) to the track (8; 308) such that the first power is supplied to the power converter (12) by the first conductor (5) of the track (8; 308) for allowing the power converter (12) to convert the supplied first power to the second power and such that the power converter (12) provides the second power to the second conductor (7) of the track (8; 308).

2. The power supply device as defined in claim 1, wherein the attaching unit (11; 111; 151; 211) is adapted to allow the power supply device (1; 101; 150; 201) to be clicked on the track (8; 308).

3. The power supply device as defined in claim 1, wherein the attaching unit (151) is adapted to attach the power supply device (150) to a frontal end of the track (8; 308).

4. The power supply device as defined in claim 1, wherein the power distribution track system (104; 204) comprises several tracks (8; 308) comprising a first conductor (5; 381, 382) for supplying the first power and a second conductor (7; 383, 384) for supplying the second power, wherein the attaching unit (111; 151; 211) is adapted to attach the power supply device to at least two of the several tracks (8; 308) for connecting the at least two tracks (8; 308) such that the first power is supplied to the power converter by the first conductor (5; 381, 382) of at least one of the at least two tracks (8; 308) and such that the power converter provides the second power to the second conductor (7; 383, 384) of at least one of the at least two tracks (8; 308).

5. The power supply device as defined in claim 4, wherein the power supply device is adapted to electrically connect at least one of a) the first conductors (5; 381, 382) of the at least two tracks (8; 308) for transposing the first power between the at least two tracks (8; 308) and b) the second conductors (7; 383, 384) of the at least two tracks (8; 308) for transposing the second power between the at least two tracks (8; 308).

6. The power supply device as defined in claim 5, wherein the power converter comprises a printed circuit board (387) and wherein the power supply device is adapted such at least one of the first conductors (381, 382) of the at least two tracks (308) and of the second conductors (383, 384) of the at least two tracks (308) are electrically connected via the printed circuit board (387).

7. The power supply device as defined in claim 4, wherein the power supply device (201) comprises an adaptation element (260) allowing a user to adapt the power supply device (201) to a desired number of tracks to which the second power is to be applied.

8. The power supply device as defined in claim 1, wherein the track (8; 308) is attached to a plane surface, wherein the power supply device (1; 101; 150; 201) comprises an outer casing being adapted for allowing the power supply device (1; 101; 150; 201) to be attached to the track (8; 308) such the outer casing has dimensions in a direction being perpendicular to the track (8; 308) and parallel to the surface, which are similar to the dimensions of the track (8; 308) in this direction.

9. An electrical load for being connected to a track of a power distribution track system, the track (8) comprising a first conductor (5) for supplying a first power and a second conductor (7) for supplying a second power, the electrical load (2) comprising:

an attaching unit (15) for attaching the electrical load (2) to the track (8) such that second power supplied by the second conductor (7) of the track (8) is provided to the electrical load (2) for powering the electrical load (2),

a voltage determination unit (18) for determining a voltage at the position of the electrical load (2) on the track (8),

an indication unit (19) for providing an indication depending on the determined voltage.

10. The electrical load as defined in claim 9, wherein the indication unit (19) is adapted to provide a gradual indication depending on the determined voltage.

11. The electrical load as defined in claim 9, wherein the indication unit (19) is adapted to comprise assignments between voltages and indications and to provide an indication based on the determined voltage and the assignments.

12. A power distribution track system for providing power to an electrical load, the power distribution track system (4; 104; 204) comprising:

a track (8; 308) with a first conductor (5) for distributing first power and with a second conductor (7) for distributing second power,

an electrical load (2) attached to the track (8; 308) such that it is electrically connected with the second conductor (7),

a power supply device (1; 101; 150; 201) as defined in claim 1 attached to the track (8; 308) such that the first power supplied by the first conductor (5; 381, 382) of the track (8; 308) is converted by the power converter (12; 112) to the second power and that the second power is supplied to the second conductor (7; 383, 384) of the track (8; 308).

13. The power distribution track system as defined in claim 12, wherein the power distribution track system (4; 104; 204) comprises a voltage determination unit (18) for determining a voltage at a position on the track (8; 308) and an indication unit (19) for providing an indication depending on the determined voltage.

14. The power distribution track system as defined in claim 13, wherein the electrical load (2) comprises the voltage determination unit (18) and the indication unit (19).

15. A method for setting up a power distribution track system, the method comprising: - providing a track (8; 308) with a first conductor (5; 381, 382) for distributing a first power and with a second conductor (7; 383, 384) for distributing a second power,

attaching an electrical load (2) to the track (8; 308) such that it is electrically connected with the second conductor (7; 383, 384),

attaching a power supply device (1; 101; 150; 201) as defined in claim 1 to the track (8; 308) such that the power converter (12) of the power supply device (1; 101; 150; 201) receives the first power from the first conductor (5; 381, 382) to be converted to the second power to be supplied to the second conductor (7; 383, 384).