EP3993566A1

EP3993566A1 - Lighting and sensor system

Info

Publication number: EP3993566A1
Application number: EP21205249.2A
Authority: EP
Inventors: René GRABHER; Guido Piai
Original assignee: GIFAS ELECTRIC GmbH
Current assignee: GIFAS ELECTRIC GmbH
Priority date: 2020-10-29
Filing date: 2021-10-28
Publication date: 2022-05-04

Abstract

A lighting system (10), in particular for marking carriageways and/or tunnel walls but not only, comprises an electrical feeder (30, 20), a plurality of inductive lighting devices (100) having a local coupler (110; 111, 112) adapted to be coupled to the electrical feeder (30, 20), a transceiver (120) and a light source or sensor (140), a control unit (60) which is connected to the electrical feeder (30, 20) and is configured to transmit control signals (61, 115) via the electrical feeder (30, 20) to the transceiver (120) of each inductive lighting device (100) via the local coupler (110; 111, 112) of the respective inductive lighting device (100), wherein the transceiver (120) is configured to transmit control signals (61, 115) to the control unit (60). The electrical feeder (30, 20) comprises an AC power source at a first frequency, in that the control unit (60) is connected to a modem (65) modulating and demodulating said control signals at a second frequency being different to the first frequency, in that a matching network (50) and a termination network (40) are provided at the beginning and at the end of the electrical feeder line (20) with a predetermined impedance, and in that each inductive lighting device (100) comprises a variable AC resonant circuit and or variable voltage limitation (131, 132) and or a variable voltage limitation circuit adjusting AC line currents of varying levels to a continuous level.

Description

TECHNICAL FIELD

The present invention relates to a lighting and sensor system, in particular but not only for marking carriageways and/or tunnel walls and to obtain sensor information from there, comprising

an electrical feeder,
a plurality of inductive lighting and / or sensor devices having a local coupler adapted to be coupled to the electrical feeder, a transceiver and a light source or sensor unit,wherein the transceiver is configured to transmit control signals to the control unit.

PRIOR ART

WO 96/02970 discloses an inductively powered lighting which receives power from adjacent concealed cables. Such lighting is especially useful for emergency lights, indicating lights and roadway signal lighting. Such lighting can be used for swimming pools, where the light is in the water, where sparks may cause explosion as in mines and stockage sites of flammable powders and where a surface on which lights are laid is prone to be replaced such as on a roadway with a tar sealed surface. WO 96/02970 discloses a low-profile LED lamp. The lamp is inductively connected with a pair of closely spaced conductors, which are spread apart at each site where a lamp unit is to be placed. The light radiated from the lamp can be changed through modulation of the current in the spaced conductors, especially as information carried within a carrier frequency different from the frequency of the power for inductive transfer. Different lamps can be addressed with different resonant frequencies. The power frequency is between 200 Hz to 2 MHz.
US 2014/008991 discloses an intelligent node for an inductive power transfer system which allows communication between a system power supply and a lamp unit and facilitates authentication of system components. The node can also control operation of the lamp unit.
WO 2011/116 404 A1 discloses a lighting device for a lighting installation for contactless transmission of energy to the lighting device, with a light source, in particular with at least one light-emitting diode, wherein the lighting device has a control unit, with which the light source can be controlled depending on control signals which can be transmitted by a control device to the lighting device, wherein the local coupler has a transmission inductance, an input for connecting an electrical feed line and a device for generating a radiofrequency voltage, which is supplied to the transmission inductance during operation of the coupler, wherein the lighting device has a transmission unit for transmitting information to the control device.
WO 2010/093997 A1 discloses configurations for a wireless power transfer for electronic devices that include at least one source magnetic resonator including a capacitively-loaded conducting loop coupled to a power source and configured to generate an oscillating magnetic field and at least one device magnetic resonator, distal from said source resonators, comprising a capacitively-loaded conducting loop configured to convert said oscillating magnetic fields into electrical energy, wherein at least one said resonator has a keep-out zone around the resonator that surrounds the resonator with a layer of non-lossy material. WO 2010/093997 optimizes the energy transfer for one induction coil with respect to wave phenomena occurring on the line as mentioned e.g. in [0447]. This transfer is inter alia shown in Fig. 44 between a source and one single device.
The thesis "AC Processing Controllers for IPT Systems" submitted by H WU in partial fulfilment of the requirements for the degree of a doctor of philosophy in electrical and computer engineering on 01-January-2009, with pages 1 to 245, XP055453643, Auckland, discloses practical implementations of AC processing pickups in chapter 4 for single lamps on a line and asserts that the equivalent resistance of a specific lamp in connection with the block diagram 4.17 of said document changes over the output current range.
US 5,559,377 A1 discloses an apparatus for electrical line communication that includes a coupler at each of two or more locations along a pair of lines, the coupler having capacitive circuits serially connected with an air-core transformer. The capacitive circuit is designed to resonate with the air-core transformer at a preselected frequency. A transmitter, receiver and modem may also be provided at each location. The apparatus incorporates a phase linear coupler which eliminates noise and is matched resistively to the characteristic impedance of the line at a preselected frequency. This apparatus therefore linearizes communication on the line and allows high speed data and voice communication over long distances.

SUMMARY OF THE INVENTION

The known lighting installations have a number of shortcomings. The length of the installation, e.g. in tunnels is usually quite limited, since mostly ignored wave phenomena appear which do not allow for the light sources to have a steady luminosity. The number of light sources, e.g. positioned every 25 or 50 meter is so limited that a tunnel of 2 kilometer length cannot be equipped with one single system. Damaged inductive lighting devices cannot be easily replaced. In WO 2011/116 404 A1 , the coupler is stationary with the electrical feeder. WO 2010/093997 optimizes the energy transfer between one single source and one single device.
DC systems have sealing problems, because galvanic contact and therefore piercing of the powering cable is required. Conventional AC systems have also sealing problems, because they use series capacitors to compensate cable inductance and therefore need a cable cut.
Based on the prior art it is an object of the invention to provide a lighting/sensor installation which provides an improved lighting/sensing for a higher number of connected inductive lighting/sensor devices.
This object is achieved with a lighting/sensor installation having the features of the above mentioned preamble of claim 1, wherein the electrical feeder comprises an AC power source at a first frequency, wherein the control unit is connected to a modem modulating and de-modulating said control signals at a second frequency different to (e.g. higher than) the first frequency, wherein a matching network and a termination network are provided at the beginning and at the end of the electrical feeder line with a predetermined frequency dependent impedance, and wherein each inductive lighting/sensor device comprises a variable AC resonant circuit adjusting AC line currents of varying levels to a continuous level.
In a preferred embodiment the variable AC resonant circuit is connected via a rectifier to a variable voltage limitation circuit to reduce the load voltage in order to lower the power to the desired level. Such a variable voltage limitation circuit can be realized with a variable constant current source or a variable load which both leads to the same goal. It can be a variable Zener diode.
The variable AC resonant circuit can comprise a tuning capacitor coupled to a main resonance capacitor and then the tuning capacitor is controlled by the microprocessor to influence the operating point in order to improve the resulting DC current supply.
The local coupler can comprise an information transmission coupler for the second, (e.g. higher) frequency and a power transmission coupler for the first (e.g. lower) frequency. The information transmission coupler usually comprises a ferromagnetic core. Preferably there is one E-core or similar for each coupler just adapted for the two different resonances and which layout of neighbouring E-cores allow to position such a lighting device on two separated wires of a cable of the electrical feeder in the correct distance one from the other without interfering with an isolation of these.
One or more lighting/sensor devices can comprise a communication interface for a direct signal exchange between the lighting/sensor devices and a handheld control device of a user who is checking or programming the different devices. Such a communication interface can be chosen especially from the group encompassing infrared communication (IR), visible light communication (VLC), near field communication (NFC) or similar interfaces.
The lighting and sensor system is called as such, since it uses a plurality of light source and sensor devices. Such single light source and sensor device can comprise a light source and a sensor, or only one of these two components.
The lighting and sensor system uses a plurality of lighting and sensor device having a local coupler, a transceiver and a light source, wherein the local coupler is configured to receive and transmit control signals when connected to an electrical feeder at a second carrier frequency being different to, e,g, higher or lower than) a first AC power transmission frequency, wherein it comprises a variable AC resonant circuit adjusting AC line currents of varying levels to a continuous level. A plurality of such lighting and sensor devices are used in a system according to the invention but can be replaced on a one by one basis. This is especially useful when the lighting and sensor devices are configured to be attached to a substrate, e.g. a road. It is also possible to use such a lighting and sensor device system for under water pond or swimming pool lighting and sensors can be used in such cases to monitor the temperature or other water parameters. Beside road lighting, especially in tunnels, such a lighting and sensor device system can be used for runway or taxiway lighting.
The advantage of the system is the versality of use of lamp and/or sensors. Although the main application will usually be lighting, it is contemplated that sensors can be provided at virtually any place along the line with just the kind of sensor adapted for the task which can be a temperature sensor, an humidity sensor, a brightness sensor, a specific gases detecting sensor, a car counting sensor, self-test or reliability sensors, etc.. The system comprises a termination with appropriate load to prevent wave phenomena. It is further possible to tune the resonant circuit for power adjustment of the individual nodes, especially if the current at resonance is too high. Bidirectional communication is possible with various ways of interfaces. The variable capacitor can comprise a tuning capacitor in parallel to the main resonance capacitor, but in other embodiments, variable capacitor alternatives can be chosen as tuning by changing the distance between the capacitor's plates or an electronic version is chosen.
Further embodiments of the invention are laid down in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described in the following with reference to the drawings, which are for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. In the drawings,

Fig. 1: shows a schematic diagram of a lighting and sensor system according to an embodiment of the invention,
Fig. 2: shows a perspective view from below of a lighting and sensor device attached on an electrical feeder of the lighting system,
Fig. 3: shows a schematical cross-section view of a lighting and sensor device of Fig. 2 embedded in a road;
Fig. 4: shows a schematic diagram of a lighting and sensor system according to a further embodiment of the invention;
Fig. 5: shows a partial view of the schematic diagram of Fig. 4 relating to the bidirectional and power connection for a two-part light and sensor device used in connection with the lighting and sensor system of Fig. 4;
Fig. 6: shows the termination network as a partial portion of the schematic diagram of Fig. 1; and
Fig. 7: shows a coupler configuration as a partial portion of the schematic diagram of Fig. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS

Fig. 1 shows a schematic diagram of a lighting and sensor system 10 according to an embodiment of the invention. Such a lighting and sensor system can in particular be used for marking carriageways and/or tunnel walls and to retrieve and transmit back sensor information relating to conditions at such a place. If it is used for marking carriageways an electrical feeder 20 is embedded in a road as substrate. Then the electrical feeder 20 comprises two wires 21 and 22 provided in parallel in the road. At specific illumination and/or sensor points, designated with the reference numeral 11, the wires 21 and 22 are accessible from above the road surface, e.g. in a hollow cylinder where the cables just pass. The cables are isolated at the passage of the specific illumination and/or points 11. In a different embodiment, not shown in the drawings, the wires 21 and 22 are replaced by two groups of two wires, wherein one group of wires will be connected via a first coupler 111 only and the second group will be connected via a second coupler 112 only, or in other words, the two group of wires are positioned in parallel and each will be connected via one dedicated coupler 111 or 112.
Reference numeral 100 indicates one lighting and sensor device which is shown as a single device from the plurality of inductive lighting and sensor devices 100 provided at different specific illumination and/or points 11. Within an application of the invention, there can be hundreds of these inductive lighting and sensor devices 100 being positioned at the predetermined places. The lighting and sensor devices 100 can comprise a light source and a sensor, or only one of these two components.
Each lighting device 100 has a local coupler with two elements 111 and 112 adapted to be coupled to the electrical feeder 20. The information transmission coupler 111 as well as the power transmission coupler 112 are preferably so-called E-cores which are symmetric solutions to form a closed or almost closed magnetic system. The electric circuit is mostly wound around the center leg 113, whose section area is twice that of each individual outer leg 114. The legs 113, 114 are configured to allow for the two cables 21 and 22 to pass between the central leg 113 and one of the outer legs 114, respectively. The E-cores can be open ferrite cores. It is also possible to use cores which can be closed or other types of closed and open cores. Fig. 7 shows a coupler configuration as a partial portion of the schematic diagram of Fig. 1 where the coil 117 of the bidirectional data connection 115 is coupled via the coupling capacitor 117' to a first microprocessor as explained below. Coil 118 of the AC power connection is coupled via the main resonance capacitor 132 and the tuning capacitor 131 with the rectifier as explained below.
The E-cores 111 and 112 act as information transmission coupler (in case of core 111) as well as the power transmission coupler (in case of core 112).
The electrical feeder 20, which can have a length of e.g. up to 2 kilometers or beyond, is connected to an AC power source 30 providing within the embodiment shown here a sinus-shaped 40 kHz AC-voltage. In other embodiments the frequency can be chosen approximately between 10 and 100 kHz. Since standing waves occur at such line lengths of 2 km and an AC frequency of 40 kHz, the current distribution along the line would not be constant. The electrical feeder 20 is therefore terminated with a termination network 40 and is to be dimensioned to match the length and number of lighting devices 100. The necessary effective losses of the termination network as well as the local shift of the remaining current maximum are design parameters. The AC voltage source 30 is connected to the two-wire electrical feeder 20 via a likewise specific coupling network 50.
Fig. 6 shows the termination network 40 as a partial portion of the schematic diagram of Fig. 1. The termination network 40 comprises an AC matching termination LCR member 41 as well as a HF matching termination LCR member 42 both connected to the two wires of cable 21, 22. This termination network 40 is configured to match the impedance for the AC power connection 116 as well as for the HF part of the communication, being the bidirectional data connection 115, in place of a short circuit connection as in the prior art.
As mentioned in the introduction, the lighting devices 100 are configured to receive control signals from a control unit 60 and to transmit information as e.g. sensor signals to the control unit. These data are modulated on a carrier at about 130kHz (HF). In other embodiments the frequency can be chosen between approximately 100 and 500 kHz. Therefore, the control unit 60 is connected via signal cables 61 with a modem 65 which modulates the information on the cables 21 and 22. The modulation can be performed in various ways known to the person skilled in the art, especially ASK, PSK or FSK to name a few.
To ensure that the standing wave phenomenon does not impede the function here either, the terminating network 40 must assume a second function. At the HF frequency (here 130 kHz), the termination should correspond as exactly as possible to the line impedance of 120 Ohm, which is the line impedance of the feeder 20, so that the wave phenomenon disappears completely. Realistic values for the termination network are for AC: 50 ohms / 25 nF at 40 kHz and for HF: 120 ohms at 130 kHz. Since the HF signal is a weak signal, the losses are not important and it can therefore be terminated directly with the line impedance. For AC supply, the line currents must be in the range of 1.5 to 4.5 Amperes. In this case a smaller real resistance has to be selected due to the power loss in the termination network 40.
The ferrite transformers 111 and 112, together with the secondary winding and parallel connected capacitors (CAP) (not shown in Fig. 1) form resonant circuits. These are tuned for the HF and AC frequencies and operate in resonance or near this resonance, if the current is quite high. The tuning can be restricted to the AC part or the HF part or can be applied in both parts. The design using separate E-cores 111 and 112 has the advantage that the levels of the other resonance frequency are significantly lower and the filters can therefore be designed more simply. In principle, a version with one core is possible; the only one coupler 110 is used and the following bidirectional data connection 115 and AC-power connection 116 only split in the lighting device 100 itself.
The lighting and sensor device 100 comprise a microprocessor 120 providing the control function for the lighting and sensor device 100 as follows.
Due to the residual standing wave phenomenon, the lighting device 100 has to be able to handle AC line currents (primary currents) of varying levels. If the line current is low, the system requires a high quality of the AC resonant circuit, a resonant frequency that is tuned as precisely as possible and a high load voltage at the operating point so that the desired active power can be drawn from the lighting device 100. If, on the other hand, the line current is high, it makes more sense to operate slightly outside the perfect resonance and with lower load voltages, so that unfavorably high reactive currents and thus losses in the resonant circuit are prevented. This issue is solved by a variable AC resonant circuit. Depending on the required operating point, the microcontroller 120 connects a tuning capacitor (TCAP 131) in parallel to the main resonance capacitor (AC CAP 132). This detunes the resonant frequency and converts less energy. Usually behind the coupler 112 is provided a variable voltage adjustment circuit behind the rectifier.
This tuned AC level provided by the tuning capacitor 131 and the main resonance capacitor 132 is then rectified in rectifier 135 and could be delivered on one side as power to the microprocessor 120 via power line 136 and to the LED's / sensors 140 via power line 137.
Fig. 7 shows a coupler configuration as a partial portion of the schematic diagram of Fig. 1 with the above mentioned reference numerals. The bidirectional data connection 115 comprises the coil 117 connected with the coupling capacitator 117' as a LC link to the first microprocessor 120. The AC power connection 116 is the connection between the coil 118 of the AC power connection together with the two capacitors 132 as main resonance capacitor together with the tuning capacitor 131.
However, it is preferred to provide a variable Zener diode circuit 150 controlled via control lines 151 by the microprocessor 120 of the lighting device 100. Such a variable Zener diode circuit 150 can additionally reduce the load voltage to lower the power to the desired level. This Zener diode circuit 150 is also controlled by the microcontroller according to the operating point. The variable Zener diode circuit is mentioned as one example for a variable voltage limitation circuit which can also be realized with a variable constant current source or a variable load.
The LEDs 140 are dimmed by the microcontroller 120 via switching regulators and can be operated with flashing sequences via the control line 152. In case of a sensor device 100, the LED would be replaced by the sensor in question. Such a sensor can be a temperature sensor, humidity sensor or gas sensing sensor to name a few applications. It is also possible to have a LED 140 as well as in parallel such a sensor connected via the lines 137 and 152 in the same way as the LED 140.
An optical IR interface 160 allows easy programming of IDs and various parameters directly on the specific lighting source, e.g. when it is built in a road 200. Instead of an IR interface such a communication interface can be chosen especially also from the group encompassing VLC, NFC or similar interfaces.
The lighting device 100 and its electronic components mentioned above basically works in the presented embodiment with three DC voltages approx. 25V, 9.3 V and 3.3 V provided by the rectifier 135. These are also operated with switching regulators. For the switching regulators it is necessary that the load voltage is always within its valid operating range. The variable Zener diode circuit 150 is also responsible for this adjustment.
The lighting source therefore comprises a transceiver which is provided by the microprocessor 120 and a light source which is provided by LED(s) 140.
The control unit 60 is connected to the electrical feeder 20 and is configured to transmit control signals via the electrical feeder 20 to the transceiver 120 of each inductive lighting device 100 via the local coupler 110 or 111/112 of the respective inductive lighting device 100. The transceiver 120 is configured to be able to transmit control signals, e.g. sensor signals, to the control unit 60.
The advantage of this tuning of each of the lighting and sensor devices 100 via the Zener diode circuit 150 is the primary current-independent load on the line by the lighting device 100. Due to the adjustable load voltage, each single lighting and sensor device 100 can determine the power consumption independently of the LED 140 operating state and other internal loads. This means a constant standing wave phenomenon. Induced oscillation behavior via the primary current due to changing operating states of the different lighting and sensor device 100 can thus be prevented. The dimensioning of the coupling 50 and termination 40 networks can therefore be chosen independent of the operating state and is fixed in advance.
Fig. 2 shows a perspective view from below of a lighting device 100 attached on the cable 20 of an electrical feeder 20 of the lighting system 10 and Fig. 3 shows a schematical cross-section view of the lighting device 100 of Fig. 2 embedded in a road 200. The lighting and sensor device 100 can have a cylindrical housing 170 to be positioned in a hole in a road 200 with side openings to allow the cable 20 to pass. The cable 20 can be separated from the beginning in the two wires 21 and 22 or can be separated at the installation point 11. Preferably the housing 170 comprises elements to maintain the wires 21 and 22 just on the underside of the E-core coupler 110 (or couplers 111, 112). The core 175 of the lighting device 100 is then positioned in the housing 170 so that the flange 171 is flush on the road 200 surface. The upper and/or side surfaces 172 of the flange are preferably translucent in order to allow the light of the LEDs 140 to pass.
Fig. 4 shows a schematic diagram of a lighting and sensor system 12 according to a further embodiment of the invention. All identical or similar features of the embodiment of Fig. 1 have the identical reference numerals; therefore, the description of these features is not repeated here. The main difference between the embodiment of Fig. 1 and Fig. 4 is related to the fact that the lighting and/or sensor device is divided into an underground part of the lighting/sensor device 100A and an above ground part of the lighting/sensor device 100B. The underground part of the lighting/sensor device 100A is applied on the electrical feeder cable 20 with the first and the second wires 21 and 22, as the device of Fig. 1. Also here it is of course possible to provide within this underground part of the embodiment of the invention a combined coupler 110 instead of the separation of the power and information transfer.
Features of Fig. 4 are also shown in Fig. 5 being a partial view of the schematic diagram of Fig. 4 relating to the bidirectional and power connection for a two-part light and sensor device used in connection with the lighting and sensor system of Fig. 4.
Here, preferredly, one second coupler pair 210A and 210B is provided with an underground coupler part or coil 210A and an above ground coupler part or coil 210B positioned one facing the other. The underground coupler part or coil 210A is preferredly encapsulated with the underground part of the lighting and/or sensor device 100A and has attachment elements working together with complementary attachment elements provided at the above ground part of the lighting and/or sensor device 100B, as e.g. a bayonet, magnetic or bonded connection (to name a few) for a removable attachment of the above ground part of the lighting and/or sensor device 100B at the underground part 100A.
Here, the road separation coupler 210 is responsible for data and energy transmission. The bidirectional data connection is connected to a (here) FSK and PSK modulation / demodulation unit for transmitting and receiving data from the above ground part of the lighting/sensor device 100B via the road separation coupler 210. On the other hand, the AC power connection and driver 116' is connected to a resonance capacitor and adjustment network 216. This second AC source 116' which is transmitting power between the underground microprocessor 120 to ― inter alia - the above ground microprocessor 120' has preferably a frequency which is 50 to 20 times higher than the AC frequency of the AC source 30. When the AC source 30 has a frequency of 40 kHz, the AC frequency of the second AC source 116' can be 600 kHz.
The resonance capacitor and adjustment network 216 and the load capacitor or resistor 121' as well as the PSK and FSK demodulation 215 and 133 provide the simultaneous transmission of power and (bi)directional communication to the above ground part of the lighting and/or sensor device 100B. There, a further main resonance capacitor is responsible to provide power to the rectifier 135' to provide power to the lighting and/or sensors 140' which would then also connected to the second microprocessor 120' which forwards the sensor data received from any sensor 140' and/or programming information from the e.g. IR sensor 160 via the load capacitor or resistor 121' towards the above ground coil 210B to be transmitted to the underground microprocessor 120.
The FSK modulation is controlled by the underground microprocessor 120. The frequency is usually a different one than the frequency of the ac voltage source 30. The FSK modulation is used for uploading data from underground part of lighting and/or sensor device 100A to the above ground part of lighting and/or sensor device 100B. PSK load modulation is used for downloading data from the above ground part of lighting and/or sensor device 100B to the underground part of lighting and/or sensor device 100A. PSK load modulation is one example for downloading the data, also a ASK load modulation (Amplitude shift keying or similar) is possible.

The road separation coupler 210 with its

parts

210A and 210B comprises two preferably planar ferrite cores 211 and 211' with corresponding coils 212 and 212', respectively. The PSK demodulator 215 and the resonance capacitor and resonance network 216 are connected together with the LC link comprising the coil 212 and capacitor 213. On the other side, coil 212' is connected with main resonance capacitor 132' and load capacitor 121', wherein the FSK demodulator 133 is connected at the above ground coupler part 210B at the coil 212' to provide the second mircoprocessor 120' with the tuning information for adjusting the load capacitor 121' part of the LC link which may include a resistor part (not shown) and which is connected as input for the rectifier 135' of this second above ground stage in a tunnel or runway lighting application. In a pool or pond lighting and sensor application this part would be immersed in the liquid environment.

LIST OF REFERENCE SIGNS

10	lighting and/or sensor system		connection
11	specific illumination or sensor point	120	first microprocessor
11	specific illumination or sensor point	120'	second microprocessor
12	lighting and/or sensor system	121'	load capacitor or resistor
20	electrical feeder cable	131	tuning capacitor
21	first wire of cable	132	main resonance capacitor
22	second wire of cable	132'	main resonance capacitor
30	AC voltages source	133	FSK demodulation
40	termination network	135	rectifier
41	AC matching LCR member	135'	rectifier
50	matching network	136	power line
60	control unit	137	power line
61	signal cable connections	140	LED and / or sensors
65	modem	140'	LED and / or sensors
100	lighting and/or sensor device	150	variable voltage limitation
100A	underground part of lighting and/or sensor device	151	control line
100A	underground part of lighting and/or sensor device	152	control line
100B	above ground part of lighting and/or sensor device	160	IR sensor
100B	above ground part of lighting and/or sensor device	170	housing
110	coupler	171	flange
111	information transmission coupler	172	top surface
111	information transmission coupler	175	core
112	power transmission coupler	200	road surface
113	central leg	210	road separation coupler
114	outer leg	210A	underground coupler part
115	bidirectional data connection	210B	above ground coupler part
115'	bidirectional data connection	211	(planar) ferrite core
116	AC power connection	211'	(planar) ferrite core
116'	AC power connection and driver	212	coil
116'	AC power connection and driver	212'	coil
117	coil of the bidirectional data connection	213	capacitor
117	coil of the bidirectional data connection	215	PSK demodulation
117'	coupling capacitor	216	resonance capacitor and adjustment network
118	coil of the AC power	216	resonance capacitor and adjustment network

Claims

A lighting and sensor system (10, 12) for marking and/or for obtaining sensor information, comprising
- an electrical feeder (30, 20),

- a plurality of inductive lighting and/or sensor devices (100; 100A, 100B) having a local coupler (110; 111, 112) adapted to be coupled to the electrical feeder (30, 20), a transceiver (120) and a light source and/or a sensor (140),

- a control unit (60) comprising a modem (65) which is connected to the electrical feeder (30, 20) and is configured to transmit control signals (61, 115) via the electrical feeder (30, 20) to the transceiver (120; 120') of each inductive lighting and/or sensor device (100; 100A, 100B) via the local coupler (110; 111, 112) of the respective inductive lighting and/or sensor device (100; 100A, 100B),
wherein the transceiver (120; 120') is configured to transmit control signals (61, 115) to the control unit (60),
characterized in that the electrical feeder (30, 20) comprises an AC power source at a first frequency, in that the modem (65) of the control unit (60) is configurede to modulate and de-modulate said control signals at a second frequency being different to the first frequency, in that a matching network (50) and a termination network (40) are respectively provided at a beginning and at an end of the electrical feeder line (20) with a predetermined impedance, and in that each inductive lighting and/or sensor device (100; 100A, 100B) comprises an AC resonant circuit (131, 132) configured to adjust AC line currents of varying levels to a continuous power level.
The lighting and sensor system of claim 1, wherein each each inductive lighting and/or sensor device (100; 100A, 100B) further comprises a rectifier (135) and a variable voltage limitation circuit (150), wherein the AC resonant circuit (131, 132) is connected via the rectifier (135) to the variable voltage limitation circuit (150) to reduce the load voltage to lower the power to the desired level.
The lighting and sensor system according to claim 2, wherein the variable voltage limitation circuit comprises a circuit from the group comprising a variable constant current source, a variable load, a variable Zener diode or a combination of these circuits.
The lighting and sensor system of any one of claims 1 to 3, wherein the variable AC resonant circuit (131, 132) comprises a main resonance capacitor (132) as well as a tuning capacitor (131) coupled to the main resonance capacitor (132) and wherein the transceiver comprises a microprocessor (120) which is configured to control the tuning capacitor (131) to or near an operating point.
The lighting and sensor system of any one of claims 1 to 4, wherein the local coupler (110; 111, 112) comprises an information transmission coupler (111) for the second frequency and a power transmission coupler (112) for the first frequency.
The lighting and sensor system of any one of claims 1 to 5, wherein the electrical feeder (20) comprises a two-wire communication channel and a two-wire power channel and wherein the local coupler (110, 111, 112) comprises a first partial coupler (111) and a second partial coupler (112) wherein the first partialcoupler (111) is coupled with the two-wire communication channel and the secondpartialcoupler (112) is coupled with the two-wire power channel.
The lighting and sensor system of any one of claims 1 to 6, wherein at least one of the plurality of light and/or sensor devices comprises an underground part (100A) connected to the coupler (110) and an above ground part (100B), wherein the above ground part (100B) is adapted to be connected to the underground part (100A), wherein the underground part (100A) and the above ground par (100B) comprise a road separation inductive coupler (210), comprising an underground coupler part (210A) and an above ground coupler part (210B), respectively, wherein the lighting and/or sensors (140') are provided in the above ground part (100B) and the underground part (100A) is configured to transmit power and data to a above ground microprocessor (120') in the above ground part (100B) to control said lighting and/or sensors (140').
The lighting and sensor system of claim 7, wherein the underground part (100A) comprises a further AC source (116') having a different frequency to the frequency of the AC source (30).
The lighting and sensor system of claim 8, wherein the further AC source (116') has a frequency 5 to 20 times greater than the frequency of the AC source (30).
The lighting and sensor system of any one of claims 1 to 9, wherein one or more of the plurality of the lighting and/or sensor devices (100; 100A, 100B) comprise a communication interface (160) for a direct signal exchange between the lighting and/or sensor devices (100; 100A, 100B) and a handheld control device.
The lighting and sensor system of claim 10, wherein the communication interface is comprised within the group encompassing IR, VLC, NFC or similar interfaces.