EP4641537A1

EP4641537A1 - Lighting system with integrated smart fire detection

Info

Publication number: EP4641537A1
Application number: EP24172319.6A
Authority: EP
Inventors: Fabio Romano; Miguel Philipp Schneider
Original assignee: Tridonic GmbH and Co KG
Current assignee: Tridonic GmbH and Co KG
Priority date: 2024-04-25
Filing date: 2024-04-25
Publication date: 2025-10-29

Abstract

The disclosure concerns a lighting system and a method for detecting a heat source, wherein the lighting system comprises a plurality of devices that include each at least one sensor. The at least one sensor is configured to measure at least one parameter indicating a temperature and to generate sensor information including the measured at least one parameter. The plurality of devices is configured to transmit the generated sensor information to a processing circuit. The processing circuit is configured to evaluate the sensor information transmitted by the plurality of devices by to determining an increase over time of the at least one parameter indicating a temperature and to compare the determined increase with a threshold. The processing circuit is configured to generate information on a detected heat source, and to output the generated information in case the determined increase exceeds the threshold.

Description

The disclosure is in the field of lighting systems and fire detection systems. The disclosure in particular concerns a lighting system and a method for detecting fires using the lighting system.
Fire alarm systems are building infrastructure systems that have the capability to detect fires in a monitored building environment, alert the occupants of the building and even emergency response forces to the presence of a detected fire and related hazards such as smoke or carbon monoxide. Regulation requires installation of fire alarm systems in many public buildings. Automated fire alarm systems include dedicated sensors, e.g., sensors for detecting smoke, heat and/or flames arranged all over the monitored environment in the building and connect the distributed sensors to a fire alarm control panel. In response to a detected fire, fire alarm systems may provide the capability to alarm the fire brigade automatically, and use audio and visual signals to warn the occupants of the building against the detected fire.
In many jurisdictions exist ample regulation concerning fire alarm systems and the cost involved in designing elements of the fire alarm system and its components, in particular for installing and putting into operation of the fire alarm system over large buildings, are significant. This reduces the proliferation of fire alarm systems to environments, which are currently not liable to install and maintain fire alarm systems.
It is an object of the invention to improve fire detection capabilities in infrastructure with regard to availability, simplicity and cost effectiveness of the fire alarm system.
The lighting system according to independent claim 1, and the light driver device, the luminaire and the method for detecting heat sources in a lighting system according to the corresponding independent claims provide advantageous solutions to the aforementioned problem.
The dependent claims define further advantageous embodiments.
The lighting system in a first aspect comprises a plurality of devices that include each at least one sensor. The at least one sensor is configured to measure at least one parameter indicating a temperature and to generate sensor information including the measured at least one parameter. The plurality of devices is configured to transmit the generated sensor information to a processing circuit. The processing circuit is configured to evaluate the sensor information transmitted by the plurality of devices. The processing circuit is further configured to determine, for evaluating the sensor information, an increase over time of the measured at least one parameter and to compare the determined increase with a threshold. Furthermore, the processing circuit is configured to generate information on a detected heat source, and to output the generated information in case the determined increase exceeds the threshold.
The plurality of devices of the lighting system may include light driver devices, but also other devices such as lighting control devices. The lighting system may further comprise further devices, even without integrated sensors, in addition to the plurality of devices that each include at least one sensor.
The at least one parameter indicating a temperature is a physical parameter that is measureable and that has an actual value (current value) that is correlated with the current ambient temperature at the position of the measurement.
The processing circuit may determine the increase over time by determining (computing) a gradient of the measured at least one parameter over time, and to compare the determined gradient with the threshold. Determining or computing a gradient over time for a time sequence of measured parameter values or a time-continuous measured parameter is computationally efficient. The gradient or slope of the parameter over time may be calculated by determining a ratio of the change in parameter value to the change in time between two distinct points on the parameter curve over time. The slope, steepness or incline of the parameter curve is indicated by the absolute value of the parameter curve. The gradient indicates an increase of the parameter curve over time for positive gradients, wherein the size of the gradient increases with an increasing steepness. Detecting a sudden increase in the parameter value based on the computed gradient by using a threshold for detecting presence of the heat source is also computationally efficient.
The lighting system enables use of information that is generally available in current light driver devices for lighting modules already for concluding based on the information that a heat source, e.g. a fire, is present within the environment covered by the lighting system.
Conventionally, a fire detection system requires installing and connecting with a mains supply grid and a communication net of a plurality of fire detecting sensors. The lighting system of the first aspect provides the capability to detect heat sources such as fires in the environment covered by the lighting system without the additional fire detecting sensors and an additional communication net for connecting the fire detecting sensors with a central fire alarm unit. The sensors already present in many driver devices for monitoring parameters such as device temperature and output voltages for driving lighting modules provide the required sensor capability. A lighting control net, e.g., a DALI based network, provides the communication capability for communicating sensor data of plural devices to a processing means for signal evaluation and heat source detection. The additional hardware cost for design, manufacturing, installation and commissioning of the additional functionality of heat source detection in the lighting system is advantageously small.
Heat sources detected by the lighting system may be fires in the building. The lighting system may also support in monitoring a molten pool or furnace in an industrial environment.
The lighting system provides an additional use for a communication net based on a lighting control standard, e.g., a DALI series standard, already connecting the devices of contemporary lighting systems. Installing a communication net over building represents a significant portion of cost for building infrastructure systems such as lighting systems and fire alarm systems.
According to an embodiment of the lighting system, the processing circuit is configured to determine the increase over time of the at least one parameter for each device individually and to compare the individually determined increase with the threshold. The processing circuit is configured to generate and output the information on the detected heat source, in case the individually determined increase exceeds the threshold for a number of devices, and the number of devices exceeds a further threshold.
The measured parameter exceeding the threshold (first threshold) indicates a sudden increase in temperature of the specific device. The number of devices, which exceed the first threshold exceeding the further threshold (second threshold), indicates an event that influences the temperature of plural devices, most probably spatially adjacent devices.
The second threshold is an integer number, in particular a small one-digit integer number exceeding one, e.g. two to five. The second threshold may be determined based on a geometry of device arrangement and a number of devices in the environment (space), which the lighting system illuminates and monitors for heat sources.
Hence, the lighting system reliably distinguishes between temperature rises of a single device due to a sudden device failure, and temperature rises due to an external heat source such as a fire, which will affect a plurality of devices simultaneously.
In an embodiment, the processing circuit of the lighting system is configured to determine the increase over time of the at least one parameter for each device individually. The processing circuit is configured to evaluate the determined increase over time of the at least one parameter further based on a position of the individual device.
Hence, the lighting system uses the usually known position of the devices of the lighting system after installation in the building, in particular a relative position of each device to the other devices or a group of devices with close positions to each other device, or with positions that are within a room or a corridor of the building. Evaluating the position of the devices enables to detect heat sources more reliably or to implement procedures and algorithms for suppressing false negative detections of fires (not detecting fires) more reliably.
For example, the processing circuit may be configured to determine the increase over time of the at least one parameter for each device individually, and to determine a spatial distribution of the determined increases over time of the at least one parameter for generating a heat map of the environment of the devices. This enables the processing circuit to estimate a position of the heat source on the generated heat map, for example.
The lighting system of an embodiment includes the processing circuit configured to determine the increase over time of the at least one parameter for each device individually. In case of the determined increase over time exceeding the threshold for at least one device, the processing circuit is configured to determine a position of the heat source as a predetermined position of one device of the plurality of devices for which the determined increase over time exceeds the threshold, and for which the processing circuit determines the increase over time of the at least one parameter to exceed the determined increase over time of the at least one parameter of the other devices of the plurality of devices for which the determined increase over time exceeds the threshold.
Hence, the lighting system assumes the position of the device with the largest increase of the parameter over time as an approximate location of the heat source. Estimating the approximate location of the heat source only requires a computationally efficient comparison of values already determined by the processing circuit.
According to an embodiment of the lighting system, the processing circuit is configured to determine the increase over time of the at least one parameter for each device individually. In case of the determined increase exceeding the threshold for one device, the processing circuit is configured for other devices of the plurality of devices, to determine the threshold for comparing the determined increase as an adapted threshold that is adjusted based on a distance between a respective other device to the at least one device. In particular, the processing circuit is configured to determine the threshold as an adapted threshold that decreases with an increasing distance of the respective other device to the one device.
This ensures that the devices that are more distant to the heat source also are taken into account for detecting a fire event and to avoid false negative detections by the lighting system of an actual fire. Furthermore, the processing circuit may generate a heat map of the environment in which the lighting system is installed.
In an embodiment, the processing circuit of the lighting system is configured to determine an average increase over time of the at least one parameter for plural devices of the plurality of devices and to compare the determined average increase with the threshold.
Hence, the lighting system reliably differentiates between individual device failures resulting in an increase in device temperature on the one hand, which is unrelated to any heat source or fire event, and an increase in device temperature of plural devices on the other hand. A sudden increase in device temperature of plural devices originates in a sudden event of a heat source radiating thermal energy externally to any of the devices of the plurality of devices of the lighting system.
In the lighting system of an embodiment, at least one device of the plurality of includes the processing circuit.
Hence, the additional heat source detection capability of the lighting system uses processing resources of one or more devices already installed in the lighting system, that are connected with the other devices with a lighting control network or communication network. For example, at least one of a microcontroller or an application specific integrated circuit (ASIC) of a light driver device integrated into the lighting network may provide the hardware for implementing the processing circuit.
Alternatively, a central device of the lighting system includes the processing circuit, e.g. a server (light control server) or central hardware of a fire alarm system of the building.
According to an embodiment, the lighting system comprises a communication network, in particular a communication network based on the DALI protocol for connecting the plurality of devices.
Hence, the lighting system does not require additional wiring or installing a wireless network for adding the functionality of detecting heat sources in the environment of the lighting system, but uses the existing infrastructure, such as a DALI-based lighting control net.
In an embodiment of the lighting system, at least one of a microcontroller or an ASIC of the plurality of devices includes the at least one sensor.
Current light driver devices include integrated circuits (IC), comprising often at least one ASIC and at least one microcontroller for implementing a control circuit of the light driver device. Many, if not most of such ICs offer a temperature sensor either integrally or connectable via a dedicated interface. ICs also regularly have a voltage measurement capability, thereby offering two potential sensors for measuring physical parameters that depend on an ambient temperature, or may be used to measure a parameter that is indicative of the ambient temperature of the IC, thereby also of a device including the IC. Thus, current lighting systems include devices already offering the basis for implementing a fire warning system, although currently not used therefore. The implementation cost for the lighting system according to the first aspect therefore may dispense with the significant cost for dedicated fire detecting sensors for an entire building that already has a basic lighting system.
In the lighting system of an embodiment, the measured at least one parameter indicating a temperature includes a device temperature of the device.
Hence, the lighting system uses an existing temperature sensor of the device that monitors the device temperature for detecting heat sources in the environment of the device. Cost for sensors for a fire alarm system are advantageously low.
According to an embodiment of the lighting system, the measured at least one parameter includes an output voltage provided by a device.
For example, the lighting system may include in the plurality of devices, light driver devices that generate and output a supply voltage for the lighting modules included in the luminaires of the lighting system. The supply voltage to the lighting modules has a characteristic temperature dependency. Hence, measuring the output voltage of the light driver devices representing the supply voltage for the lighting modules enables to measure a parameter that is indicative of the temperature. Current light driver devices include measuring means for the supply voltage provided by the light driver module. For determining the temperature based on the measured output voltage (indirect temperature measurement), knowledge of the current dimming value set for the light driver module controlling the output of at least one lighting module is advantageous.
In the lighting system of an embodiment, the plurality of devices is configured to transmit the sensor information of a device of the plurality of devices together with associated dimming information of the device, wherein the device is a light driver device.
Hence, the processing circuit has the information for an indirect measurement of the temperature based on a measured voltage that is generated and output by the light driver device.
The light driver device according to a second aspect comprises at least one sensor configured to measure at least one parameter indicating a temperature and to generate sensor information including the measured parameter. The light driver device further comprises an interface configured to receive further sensor information including the measured at least one parameter indicating a temperature from a plurality of devices. The light driver device further comprises a processing circuit configured to evaluate the acquired sensor information and the received further sensor information. The processing circuit is configured to determine, for evaluating the acquired sensor information the received further sensor information, an increase over time of the measured at least one parameter and of the measured at least one parameter received in the further sensor information and to compare the determined increase over time with a threshold. Furthermore, the processing circuit is configured to generate information on a determined heat source, and to output the generated information in case the determined increase over time exceeds the threshold.
The luminaire according to a third aspect includes at least one light driver device according to the second aspect.
The method for detecting a heat source according to a fourth aspect for a lighting system comprises a plurality of devices that each include at least one sensor. The method comprises measuring, by the at least one sensor, at least one parameter indicating a temperature for generating sensor information. The method proceeds with transmitting the generated sensor information to a processing circuit. The processing circuit evaluates the sensor information transmitted by the plurality of devices, wherein evaluating the sensor information includes determining an increase over time of the at least one parameter indicating a temperature and comparing the determined increase over time with a threshold. The processing circuit generates, in case the determined increase over time exceeds the threshold, information on the detected heat source and outputs the generated information.
The method for detecting a heat source according to the fourth aspect, the light driver device according to the second aspect and the luminaire according to the third aspect achieve corresponding advantageous effects as discussed with reference to the lighting system of the first aspect.
The following description of embodiments refers to the figures, in which

Fig. 1 shows an application scenario using a lighting system according to an embodiment;
Fig. 2 provides an overview over the architecture of a lighting system of a first embodiment;
Fig. 3 provides an overview over the architecture of a lighting system of a second embodiment; and
Fig. 4 presents a flowchart illustrating major steps of the method for detecting heat sources implemented in a lighting system according to an embodiment.

In the figures, corresponding elements have the same reference signs. The discussion of the figures avoids discussion of same reference signs in different figures wherever considered possible without adversely affecting comprehensibility and avoiding unnecessary repetitions for sake of conciseness.
Fig. 1 shows an application scenario using a lighting system 1 according to an embodiment.
The lighting system 1 is arranged to illuminate a room 10 of the building. The room 10 is an example of the environment of the lighting system 1.
The lighting system 1 comprises a plurality of luminaires L1, L2, L3, L4, L5, L6 that are arranged under the ceiling of the room 10. The luminaires L1, L2, L3, L4, L5, L6 illuminate the entire room 10 and therefore are arranged spatially apart from each other.
Due to illuminating the entire space of the room 10, the luminaires L1, L2, L3, L4, L5, L6 offer a coverage of the entire room 10. Each of the luminaires L1, L2, L3, L4, L5, L6 includes at least one light driver device 2, 3, 4, 5, 6, 7 and at least one lighting module not explicitly shown in fig. 1.
The at least one lighting module may include light emitting diodes (LEDs) as light emitting elements for providing the illumination of the room 10. Using LEDs as light emitting elements in the luminaires L1, L2, L3, L4, L5, L6 is advantageous in present circumstances, as LEDs provide an efficient conversion of electric energy into emitted light energy and radiate only a small amount of heat during operation even at a high dimming level corresponding to a high amount of emitted light. Hence, operating LEDs close to a temperature sensor in the luminaire has only small effect on the temperature measured by a sensor 16 in the light driver device 2, 3, 4, 5, 6, 7.
Each light driver device 2, 3, 4, 5, 6, 7 has a mains grid interface to an AC mains grid not depicted in fig. 1 and generates a DC current (LED current I_LED) for supplying the at least one lighting module of the luminaire L1, L2, L3, L4, L5, L6 with a supply current I_LED output at a DC supply voltage V_LED. The light driver device 2, 3, 4, 5, 6, 7 includes at least one AC/DC converter circuit, which may be implemented in switched mode power supply topology (SMPS).
Current light driver devices 2, 3, 4, 5, 6, 7 include a control circuit, which regularly comprises at least one microcontroller and an application specific integrated circuit (ASIC).
The lighting system 1 of fig. 1 includes a central control device comprising a communication interface 8 and a processing circuit 9.
The communication interface 8 enables the central control device and, in particular, the processing circuit 9 to communicate via a wireless or wired communication net with the luminaires L1, L2, L3, L4, L5, L6, in particular with communication interfaces 17 of the light driver devices 2, 3, 4, 5, 6, 7.
The lighting system 1 of fig. 1 comprises a plurality of devices that include at least one sensor 16 in in each light driver device 2, 3, 4, 5, 6, 7. The at least one sensor 16 is configured to measure at least one parameter indicating a temperature and to generate sensor information including the measured at least one parameter.
The at least one parameter indicating a temperature is a physical parameter that is measureable and that has a current value that is correlated with the current ambient temperature at the position of the measurement. For example, the at least one parameter includes a measured device temperature of the light driver device 2, 3, 4, 5, 6, 7. In this example, the processing circuit 9 performs processing based on a direct measurement of the temperature. The lighting system 1 uses an existing temperature sensor 16 of the light driver device 2, 3, 4, 5, 6, 7 that monitors the device temperature for detecting heat sources 11 in the environment of the device. Sensor-related cost for sensors for implementing a fire alarm capability for the lighting system 1 are advantageously low.
Alternatively or additionally, the at least one parameter includes a measured output voltage provided by the light driver device 2, 3, 4, 5, 6, 7 to the lighting module of the luminaire L1, L2, L3, L4, L5, L6. In this example, the processing circuit 9 performs processing based on an indirect measurement of the temperature.
Conventional lighting systems include in the plurality of light driver devices 2, 3, 4, 5, 6, 7 that generate and output a supply voltage for lighting modules of the luminaire L1, L2, L3, L4, L5, L6 of the lighting system 1. The supply voltage to the lighting modules has a characteristic temperature dependency. Hence, measuring the output voltage of the light driver devices 2, 3, 4, 5, 6, 7 that represent a supply voltage for the lighting modules enables to measure a parameter that is indicative of the temperature. Current light driver devices 2, 3, 4, 5, 6, 7 include measuring means for the supply voltage provided by the light driver device 2, 3, 4, 5, 6, 7. For determining the temperature based on the measured output voltage using the indirect temperature measurement, knowledge of the current dimming value set for the light driver module controlling the output of at least one lighting module is necessary.
The plurality of light driver devices 2, 3, 4, 5, 6, 7 is configured to transmit the generated sensor information including the at least one parameter to the processing circuit 9.
The processing circuit 9 is configured to evaluate the sensor information transmitted by the plurality of light driver devices 2, 3, 4, 5, 6, 7. For evaluating the sensor information, the processing circuit 9 is in particular configured to determine an increase over time of the measured at least one parameter and to compare the determined increase with a first threshold.
The processing circuit 9 may determine the increase over time by computing a gradient of the measured at least one parameter over time, and to compare the determined gradient with the first threshold. The processing circuit 9 computes the gradient over time for a time sequence of measured parameter values or a time continuous measured parameter based on the measured parameter values received in the sensor information. The gradient of the at least one parameter over time may be calculated by determining a ratio of the change in the measured parameter values to the change in time between two distinct points on the parameter curve over time. The determined gradient over time indicates an increase of the parameter curve with time for positive gradients and the size of the gradient increases with an increasing temperature increase.
The processing circuit 9 is in particular configured to determine an increase over time of the measured at least one parameter and to compare the determined increase over time with the first threshold. In case the determined increase exceeds the first threshold, the processing circuit 9 generates information on the detected heat source 11 and outputs the generated information.
The processing circuit 9 of the embodiment determines the increase over time of the at least one parameter for each light driver devices 2, 3, 4, 5, 6, 7 individually and compares the individually determined increase with the first threshold. The processing circuit 9 generates and outputs the information on the detected heat source 11, in case the individually determined increase for exceeds the first threshold for a number of the light driver devices 2, 3, 4, 5, 6, 7, and the number of devices for which the determined increase exceeds the first threshold exceeds a second threshold (further threshold).
The measured parameter exceeding the threshold (first threshold) indicates a sudden increase in temperature of the specific light driver device 2, 3, 4, 5, 6, 7.
The number of devices, which exceed the first threshold, exceeding the second threshold indicates an event that influences the temperature of plural devices of the light driver devices 2, 3, 4, 5, 6, 7, most probably spatially adjacent devices of the light driver devices 2, 3, 4, 5, 6, 7.
In the specific scenario of fig. 1, the light driver devices 3, 4 of the luminaires L2, L3 will provide sensor information, for which the processing circuit 9 determines a respective increase with time that exceeds the first threshold.
Depending on the size of the heat emitted by the heat source 11, the light driver devices 2, 5 of the luminaires L1, L4 may also provide sensor information, for which the processing circuit 9 determines a respective increase with time that exceeds the first threshold.
In the discussed example, the number of light driver devices 2, 3, 4, 5, 6, 7 for which the determined increase in the parameter indicative of the temperature exceeds the first threshold, is at least two, most probably even four devices of the light driver devices 2, 3, 4, 5, 6, 7 arranged in the room 10. The processing circuit 9 determines the number of devices of the light driver devices 2, 3, 4, 5, 6, 7 with the second threshold. In case the processing circuit 9 determines that the number of devices of the light driver devices 2, 3, 4, 5, 6, 7 exceeds the second threshold, the processing circuit 9 determines that there is a heat source 11 in the room 10 with the light driver devices 2, 3, 4, 5, 6, 7.
In the example of fig. 1, the second threshold may be set to two or four. The second threshold may depend on the number of light driver devices 2, 3, 4, 5, 6, 7 representing a group of luminaires L1, L2, L3, L4, L5, L6 of a room 10 as a criterion. The second threshold may vary depending on a size of the group for different groups that include different numbers of light driver devices 2, 3, 4, 5, 6, 7.
The second threshold enables the lighting system 1 to reliably distinguish between temperature rises of a single light driver devices 2, 3, 4, 5, 6, 7 due to a sudden device failure, and temperature rises due to the external heat source 11 such as a fire, which will affect a plurality of light driver devices 2, 3, 4, 5, 6, 7 almost simultaneously.
The second threshold may be preset during a commissioning process of the lighting system 1 and stored in a data storage (memory) of the processing circuit 9.
The second threshold is an integer number, in particular a small one-digit integer number exceeding one, e.g. two to five. The second threshold may be selected based on a geometry of device arrangement in the space, which the lighting system illuminates and monitors.
The processing circuit 9 of fig. 1 evaluates the determined increase over time of the at least one parameter further based on a position of the individual device of the plurality of light driver devices 2, 3, 4, 5, 6, 7.
During a commissioning process of the lighting system 1, the respective positions of the light driver devices 2, 3, 4, 5, 6, 7 of the lighting system 1 in the room 10 after installation are fixed, determined and stored. The positions may also be stored associated with a part of building, e.g., the positions of the light driver devices 2, 3, 4, 5, 6, 7 may be stored associated with the room 10.
The position of the light driver devices 2, 3, 4, 5, 6, 7 may include in particular a relative position of each device of the light driver devices 2, 3, 4, 5, 6, 7 relative to the other devices or a group of devices of the light driver devices 2, 3, 4, 5, 6, 7. Evaluating the position of the light driver devices 2, 3, 4, 5, 6, 7 enables the processing circuit 9 to the detect the heat source 11 more reliably or to implement procedures for more reliably suppressing false negative detections of heat sources 11, resulting in missed detections of events, which would result in a fire alarm if correctly detected.
The processing circuit 9 of the example of fig. 1 determines the increase over time of the at least one parameter for each device of the light driver devices 2, 3, 4, 5, 6, 7 individually. The processing circuit 9 determines a spatial distribution of the determined increases over time of the at least one parameter for generating a heat map of the room 10 representing the environment of the light driver devices 2, 3, 4, 5, 6, 7. The processing circuit 9 estimates a position of the heat source 11 on the generated heat map for the room 10. In fig. 1, the processing circuit 9 determines the heat source 11 to be associated with the known positions of light driver devices 3, 4 and luminaires L2, L3.
The processing circuit 9 of the example of fig. 1 determines the position of those light driver device 2, 3, 4, 5, 6, 7 that have a the largest increase over time of the parameter as an approximate location of the heat source 11. The processing circuit 11 estimates the approximate location of the heat source 11 by performing a comparison of the values of the increase over time of the parameter indicative of the increase in temperature.
The processing circuit 9 of the example of fig. 1 determines the first threshold when comparing the determined increase with the first threshold as an adapted first threshold that is adjusted based on a distance between the respective light driver device 2, 3, 4, 5, 6, 7 to the light driver device 2, 3, 4, 5, 6, 7 for which the increase over time of the parameter indicative of the temperature exceeds the (not adapted) first threshold.
In the example of fig. 1, the processing circuit 9 determines the increase over time of the parameter to exceed the first threshold for light driver devices 3, 4. The processing circuit 9 then adjusts the first threshold to an adapted first threshold for light driver devices 2, 5, 6, 7 based on the distance of the light driver devices 2, 5, 6, 7 to the light driver devices 3, 4. The processing circuit 9 then compares for the light driver devices 2, 5, 6, 7, individually the determined increase of the parameter indicative of the temperature with the respective adapted first threshold that decreases with increasing distance of the respective other device of the light driver devices 2, 5, 6, 7 to the light driver devices 3, 4.
In the exemplary scenario of fig. 1, the comparison with the respective adapted first threshold results in determining that the determined increase over time of the parameter indicative of the temperature exceeds the respective adapted first threshold for light driver devices 2, 5.
Light driver devices 2, 5 that are more distant to the heat source 11 than the light driver devices 3, 4 are also taken into account for detecting the heat source 11. This provides the effect of avoiding false negative detections (not detecting) by the lighting system 1 of an actual fire.
The processing circuit 9 may generate a heat map of the room 10 representing the environment in which the lighting system 1 is installed that is refined with regard to plural temperature zones within the room 10 due to evaluating the increase over time based on both the first threshold and the adapted first threshold.
The heat source 11 detected by the processing circuit 9 of the example of fig. 1 is a fire in room 10 of the building. In particular, the processing circuit 9 generates and outputs the generated information on the detected heat source 11 to a fire alarm unit 13.
The application scenario in fig. 1 also includes a known fire alarm sensor 12 arranged in the room 10. A dedicated signal line connects the fire alarm sensor 12 with a fire alarm control unit 13.
The fire alarm sensor 12 covers the entire room 10, but will have difficulties in locating the fire precisely in a direction extending along the locations of the luminaires L1, L2, L3, L4, L5, L6 under the ceiling of the room 10. Contrary to a fire alarm system that uses solely the fire alarm sensor 12 and the fire alarm unit 13, the lighting system 1 executes processing that enables to estimate the position of the fire 11 in the room 10 relative to the location of the luminaires L1, L2, L3, L4, L5, L6. The processing circuit 9 estimates the position of the heat source 11 in the room 10 relative to the location of the luminaires L1, L2, L3, L4, L5, L6 based on the sensor information provided by the luminaires L1, L2, L3, L4, L5, L6 and the predetermined position of each luminaire L1, L2, L3, L4, L5, L6.
The fire alarm unit 13 of fig. 1 may combine the alarm signal output by the fire alarm sensor 12 with the output signal including the information on the detected heat source 11 provided by the processing circuit 9 based on sensor information provided by the sensors 16 included in the luminaires L1, L2, L3, L4, L5, L6.
The fire alarm control unit 13 may control actuators of the fire alarm system implemented using the lighting system 1 that perform actions including visual warning, acoustic warning, or escape route guidance for occupants of the room 10 in case a fire is detected by either the fire alarm sensor 12 and the lighting system 1.
The embodiment of fig. 1 implements a processing circuit 9 that is configured to determine the increase over time of the at least one parameter for each light driver device 2, 3, 4, 5, 6, 7 individually. The processing circuit 9 determines whether the determined increase over time of the at least one parameter indicative of the temperature exceeds the first threshold for each light driver device 2, 3, 4, 5, 6, 7 individually.
Alternatively or additionally, the processing circuit 9 of the lighting system may determine an average increase over time of the at least one parameter for plural devices of the plurality of light driver device 2, 3, 4, 5, 6, 7 and to compare the determined average increase for the plural devices with the respectively selected first threshold. By performing processing based on an average increase over time of the parameter indicative of the temperature, the processing circuit 9 of the lighting system 1 even more reliably differentiates between individual device failures and an increase in device temperature of plural devices due to a new heat source 11 in the room 10. An individual device failure may result in an increase in device temperature of one device of the plural light driver devices 2, 3, 4, 5, 6, 7, which is unrelated to the heat source 11 or any fire event. Contrary thereto, the external heat source 11 radiates thermal energy externally to any of the devices of the plurality of light driver device 2, 3, 4, 5, 6, 7 of the lighting system 1. The thermal energy radiated by the heat source 11 increases the ambient temperature, and therefore the device temperature of plural light driver devices 2, 3, 4, 5, 6, 7.
The discussed processing in the processing circuit 9 focuses on detecting temperature increases using available sensors 16 of light driver device 2,3, 4, 5, 6, 7 of the lighting system 1 instead of using single dedicated sensors for fire detections as is presently state of the art.
Fig. 2 provides an overview over the architecture of a lighting system 1 of a first embodiment.
The elements of the lighting system 1 according to the first embodiment have already been described with reference to fig. 1. The first embodiment of the lighting system 1 connects the luminaires L1, L2, L3, L4, L5, L6 via communication network with a central control device of the lighting system 1, which includes the communication interface 8 and the processing circuit 9. Fig. 2 indicates the central control device with a dotted line.
The processing circuit 9 of the first embodiment outputs the generated information on the detected heat source 11 in an output signal 14 via the communication interface 8.
The processing circuit 9 of the first embodiment of the lighting system 1 may form part of a light server that often forms already part of known lighting systems.
Fig. 3 provides an overview over the architecture of a lighting system 1 of a second embodiment.
Many elements of the lighting system 1 according to the second embodiment have already been described with reference to fig. 1. The second embodiment of the lighting system 1 dispenses with the central control device of the first embodiment.
The light driver device 5' of the luminaire L4 of the second embodiment comprises at least one sensor 16, which is configured to measure at least one parameter indicating a temperature and to generate sensor information including the measured parameter. The light driver device 5' further comprises an interface 17, implemented as a DALI interface, which is configured to receive further sensor information including the measured at least one parameter indicating a temperature from a plurality of other devices of the light driver devices 2, 3, 4, 6, 7. The light driver device 5' further comprises a processing circuit 15 configured to evaluate the acquired sensor information from the sensor 16 and the received further sensor information from the plural other light driver devices 2, 3, 4, 6, 7. The processing circuit 15 is configured to determine, for evaluating the acquired sensor information and the received further sensor information, an increase over time of the measured at least one parameter of the sensor 16 and of the measured at least one parameter received in the further sensor information from the other light driver devices 2, 3, 4, 6, 7. The processing circuit 15 is configured to compare the determined increases over time with the first threshold. Furthermore, the processing circuit 15 is configured to generate information on a determined heat source 11 in the room 10, and to output the generated information in case the determined increases exceeds the first threshold.
The lighting system 1 of the second embodiment includes therefore at least one device of the plurality of light driver device 2, 3, 4, 5, 6, 7 that includes the processing circuit 15 corresponding to the processing circuit 9 of the first embodiment.
In the second embodiment of the lighting system 1, the additional heat source detection capability of the lighting system 1 uses processing resources of one of the light driver devices 2, 3, 4, 5, 6, 7 that is connected with the other devices of the light driver devices 2, 3, 4, 5, 6, 7 with a communication network 18. The communication network 18 may be lighting control network or a general communication network, e.g. a wired network or a wireless network. In the example of fig. 3, at least one of a microcontroller or an ASIC of the light driver device 5' integrated into the lighting system 1 may provide the hardware for the implementing the processing circuit 15.
The lighting system 1 of fig. 3 comprises the communication network 18, in particular a communication network based on the DALI protocol for connecting the plurality of light driver devices 2, 3, 4, 5, 6, 7. The lighting system 1 does not require additional wiring or installing a parallel wireless network for adding the functionality of detecting heat sources 11 in the environment of the lighting system 1, but uses the existing infrastructure of the DALI-based lighting control net for the additional functionality of detecting heat sources 11.
Current light driver devices 2, 3, 4, 5, 6, 7 include ICs that comprise at least one ASIC and at least one microcontroller for implementing a control circuit of the light driver device 2, 3, 4, 5, 6, 7.
Many ICs include a temperature sensor either integrally or connectable via a dedicated interface of the IC. ICs also regularly have a voltage measurement functionality, thereby offering two potential sensors 16 for measuring physical parameters that indicate the device temperature of the IC, or of a light driver device 2, 3, 4, 5, 6, 7 that includes the IC. Thus, existing lighting systems sometimes include devices already offering the basis for implementing a fire warning system, although currently not used therefore. The implementation cost for the lighting system 1 according to the first aspect therefore may dispense with the significant cost for dedicated fire detecting sensors 12 for an entire building that already has a basic lighting system.
Fig. 4 presents a flowchart illustrating major steps of the method for detecting heat sources implemented in a lighting system 1 according to an embodiment.
The method for detecting a heat source 11 is executed in a lighting system 1 as discussed with reference to figs. 1, 2, and 3. The lighting system 1 comprises s a plurality of devices that each include at least one sensor 16. The plurality of devices may be lighting devices 2, 3, 4, 5, 6, 7.
The flowchart of fig. 4 starts with a step 20 of acquiring sensor data. In step 20, the at least one sensor 16 of each device measures at least one parameter indicating a temperature. The at least one sensor 16 generates sensor information including the measured parameter.
The plurality of devices each transmit the generated sensor information to a processing circuit 9, 15.
In step S21, the processing circuit 9, 15 evaluates the sensor information transmitted by the plurality of devices to the processing circuit 9, 15.
For evaluating the received sensor information, the processing circuit 9, 15 determines an increase over time of the at least one parameter indicating a temperature received in the sensor information from each or the plurality of devices 2, 3, 4, 5, 6, 7 and compares the determined increase over time with a threshold.
In case the determined increase of the at least one parameter indicating a temperature does not exceed the threshold (NO) in step 22, the control circuit 9, 15 determines that a heat source 11 is not detected and proceeds to step 20, in which new sensor information is acquired and thereby starting a new processing cycle.
In case the determined increase of the at least one parameter indicating a temperature exceeds the threshold (YES) in step 22, the control circuit 9, 15 determines that a heat source 11 is detected and proceeds in step 23 with generating information on the detected heat source 11. The processing circuit 9, 15 then outputs the generated information on the detected heat source 11.
In step 24 following to step 23, an actuator executes a predetermined action in response to the information on the detected heat source 11 output by the control circuit 9, 15.
The predetermined action may include generating and outputting at least one of an acoustic warning and a visual warning to occupants of the building.
The predetermined action may include alarming a fire brigade, e.g., via an automated call or message to an emergency services center.
The predetermined action may include activating a route guidance system installed in the building for supporting an evacuation of the building by its occupants. The predetermined action may include evaluating location information of the detected heat source provided by the lighting system 1 in the output information on the detected heat source 11. The route guidance system may then dynamically adjust emergency escape route(s) based on the evaluated location information to guide the occupants safely out of the building.
The predetermined action may include activating a dynamic route guidance system installed in the building for supporting a fire response team in planning its steps and fighting the fire.
All steps which are performed by the various entities described in the present disclosure as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities.
In the claims as well as in the description the word "comprising" does not exclude the presence of other elements or steps.
The indefinite article "a" or "an" does not exclude a plurality.
A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that different dependent claims recite certain measures and features of the control circuit does not exclude that a combination of these measures and features cannot combined in an advantageous implementation.
The features described in the discussion of specific embodiments and depicted in the figures may be combined with each other for the invention defined in the attached claims.

Claims

Lighting system comprising a plurality of devices (2, 3, 4, 5, 6, 7) that include each at least one sensor (16),
the at least one sensor (16) is configured to measure at least one parameter indicating a temperature and to generate sensor information including the measured at least one parameter,

the plurality of devices (2, 3, 4, 5, 6, 7) is configured to transmit the generated sensor information to a processing circuit (9, 15),

the processing circuit (9, 15) is configured to evaluate the sensor information transmitted by the plurality of devices (2, 3, 4, 5, 6, 7),

wherein the processing circuit (2, 3, 4, 5, 6, 7) is configured to determine an increase over time of the measured at least one parameter and to compare the determined increase with a threshold, and,

the processing circuit (9, 15) is configured to generate information on a detected heat source (11), and to output the generated information in case the determined increase exceeds the threshold.
Lighting system according to claim 1, wherein
the processing circuit (9, 15) is configured to determine the increase over time of the at least one parameter for each device (2, 3, 4, 5, 6, 7) individually and to compare the individually determined increase with the threshold, and

the processing circuit (9, 15) is configured to generate and output the information on the detected heat source (11), in in case the individually determined increases exceed the threshold for a number of devices (2, 3, 4, 5, 6, 7) and the number of devices (2, 3, 4, 5, 6, 7) exceeds a further threshold.
Lighting system according to claim 1 or 2, wherein
the processing circuit (9, 15) is configured to determine the increase over time of the at least one parameter for each device (2, 3, 4, 5, 6, 7) individually, and to evaluate the determined increase over time of the at least one parameter further based on a position of the device (2, 3, 4, 5, 6, 7).
Lighting system according to one of the preceding claims, wherein the processing circuit (9, 15) is configured
to determine the increase over time of the at least one parameter for each device (2, 3, 4, 5, 6, 7) individually, and

in case of the determined increase exceeding the threshold for at least one device (2, 3, 4, 5, 6, 7),

to determine a position of the heat source (11) as a predetermined position of one device (2, 3, 4, 5, 6, 7) of the plurality of devices ( 2, 3, 4, 5, 6, 7) for which the determined increase exceeds the threshold and for which the processing circuit (9, 15) determines the increase over time of the at least one parameter to exceed the determined increase over time of the at least one parameter of the other devices (2, 3, 4, 5, 6, 7) of the plurality of devices (2, 3, 4, 5, 6, 7) for which the determined increase exceeds the threshold.
Lighting system according to one of the preceding claims, wherein the processing circuit (9, 15) is configured
to determine the increase over time of the at least one parameter for each device (2, 3, 4, 5, 6, 7) individually, and

in case of the determined increase exceeding the threshold for one device (2, 3, 4, 5, 6, 7),

for other devices (2, 3, 4, 5, 6, 7) of the plurality of devices (2, 3, 4, 5, 6, 7),

the processing circuit (9, 15) is configured to determine the threshold for comparing the determined increase as an adapted threshold that is adjusted based on a distance between the respective other device (2, 3, 4, 5, 6, 7) to the at least one device (2, 3, 4, 5, 6, 7), in particular as an adapted threshold that decreases with increasing distance of the respective other device (2, 3, 4, 5, 6, 7) to the one device (2, 3, 4, 5, 6, 7).
Lighting system according to one of the preceding claims, wherein
the processing circuit (9, 15) is configured to determine an average increase over time of the at least one parameter for plural devices (2, 3, 4, 5, 6, 7) of the plurality of devices (2, 3, 4, 5, 6, 7) and to compare the determined average increases with the threshold.
Lighting system according to one of the preceding claims, wherein
at least one device (5') of the plurality of devices (2, 3, 4, 5, 5', 6, 7) includes the processing circuit (15), or

a central device of the lighting system including the processing circuit (9).
Lighting system according to one of the preceding claims, wherein the lighting system comprises
a communication network (18), in particular a communication network (18) based on the DALI protocol for connecting the plurality of devices (2, 3, 4, 5, 5', 6, 7).
Lighting system according to one of the preceding claims, wherein
at least one of a microcontroller or ASIC included in the plurality of devices (2, 3, 4, 5, 5', 6, 7) comprises the at least one sensor (16).
Lighting system according to one of the preceding claims, wherein
the measured at least one parameter includes a temperature of a device (2, 3, 4, 5, 5', 6, 7).
Lighting system according to one of the preceding claims, wherein
the measured at least one parameter includes an output voltage provided by a device (2, 3, 4, 5, 5', 6, 7).
Lighting system according to one of the preceding claims, wherein
the plurality of devices (2, 3, 4, 5, 6, 7) is configured to transmit the sensor information of a device (2, 3, 4, 5, 5', 6, 7) together with associated dimming information of the device (2, 3, 4, 5, 5', 6, 7).
Light driver device, comprising
at least one sensor (16) configured to measure at least one parameter indicating a temperature and to generate sensor information including the measured parameter,

an interface (16) configured to receive further sensor information including the measured at least one parameter indicating a temperature from a plurality of devices (2, 3, 4, 6, 7),

a processing circuit (15) configured to evaluate the acquired sensor information and the received further sensor information,

wherein the processing circuit (15) is configured to determine, for evaluating the acquired sensor information and the received further sensor information, an increase over time of the measured parameter included in the acquired sensor information and the received further sensor information and to compare the determined increase with a threshold, and

the processing circuit (15) is configured to generate information on a determined heat source (11), and to output the generated information in case the determined increase exceeds the threshold.
Luminaire including at least one light driver device (5') according to claim 13.
Method for a lighting system (1) for detecting a heat source (11),
wherein the lighting system (1) comprises a plurality of devices (2, 3, 4, 5, 5',6, 7) that each include at least one sensor (16),

measuring (20), by the at least one sensor (16), at least one parameter indicating a temperature for generating sensor information,

transmitting the generated sensor information to a processing circuit (9, 15),

evaluating (21, 22), by the processing circuit (9, 15), the sensor information transmitted by the plurality of devices (2, 3, 4, 5, 5', 6, 7),

wherein evaluating the sensor information (21, 22) includes determining an increase over time of the at least one parameter indicating a temperature and comparing the determined increase with a threshold, and,

generating (23), by the processing circuit (9, 15), in case the determined increase exceeds the threshold, information on the detected heat source (11), and outputting the generated information.