Illumination system

Abstract

To provide an illumination system capable of notifying of lifespan information free from temporary temperature changes.SOLUTION: A disclosed illumination system includes: a light source having an LED; and a control unit configured to calculate the lifespan information of the light source from the average temperature of the light source and the accumulated lighting time of the light source, and to notify the lifespan information to the outside.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to lighting systems. [Background technology]

[0002] Patent Document 1 discloses an illumination device including a replaceable lamp having at least one light-emitting element, a lighting device that supplies power to the lamp to light the light-emitting element, and an illuminance correction unit that controls dimming of the lamp. The illuminance correction unit includes a timer that measures the cumulative lighting time of the light-emitting element, and a memory that stores the cumulative lighting time measured by the timer. The illuminance correction unit uses an illuminance correction characteristic that indicates the correspondence between the cumulative lighting time and the dimming ratio of the light-emitting element, and determines the dimming ratio of the light-emitting element based on the cumulative lighting time stored in the memory. The illuminance correction characteristic is set to the correspondence between the cumulative lighting time and the dimming ratio of the light-emitting element, and is stored in the memory, so that the light output of the light-emitting element is kept constant even if the cumulative lighting time of the light-emitting element increases. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5607980 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the use of LEDs as light sources in the lighting field has resulted in longer life spans for lighting fixtures. As a result, lighting fixtures are replaced less frequently, and manufacturers need to approach users when it is time to replace them. One such time is when the lighting fixture reaches the end of its lifespan. However, lighting fixtures are generally made up of many components, including LED light sources, and it is difficult to calculate the lifespan of each of these components. As a result, it has become common to use the lifespan of the LED, which is assumed to have the shortest lifespan of all the components, as the lifespan of the lighting fixture.

[0005] In the lighting device of Patent Document 1, the illuminance correction characteristic is used to determine the dimming ratio corresponding to the accumulated lighting time of the light source. However, for lighting devices installed in places where the light output cannot be reduced, it is desirable to replace them with new ones at an appropriate time. The lifespan of an LED varies depending on the type or temperature of the LED. For this reason, a technology is required to estimate the lifespan from the temperature of the LED, for example, and to notify the outside.

[0006] Here, it is assumed that the ambient temperature around the LED will be high in the summer. Even within the context of a single day, for example, on a sunny day the temperature will rise due to the influence of sunlight, and the temperature difference between day and night will be large. However, degradation of a light source is generally due to changes in luminous flux maintenance caused by the average temperature. For this reason, it is thought that degradation of a light source is unlikely to be affected by temporary changes in temperature.

[0007] An object of the present disclosure is to provide a lighting system that can notify lifespan information without being affected by temporary changes in temperature. [Means for solving the problem]

[0008] The lighting system according to the present disclosure includes a light source having an LED, and a control device that calculates life information of the light source from an average value of the temperature of the light source and an accumulated lighting time of the light source, and notifies the outside of the life information. Effect of the Invention

[0009] According to the lighting system of the present disclosure, the lifetime information of the light source is calculated using the average value of the temperature of the light source, and the lifetime information is notified to the outside. Therefore, the lifetime information can be notified without being affected by temporary changes in temperature. [Brief description of the drawings]

[0010] [Figure 1] 1 is a circuit block diagram of a lighting system according to a first embodiment. [Diagram 2]FIG. 4 is a diagram showing an example of instantaneous and average temperatures of a light source. [Diagram 3] FIG. 4 is a diagram showing an example of instantaneous and average temperatures of a light source. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The lighting system according to the present embodiment will be described with reference to the drawings. The same or corresponding components are designated by the same reference numerals, and the repeated description may be omitted.

[0012] Embodiment 1 1 is a circuit block diagram of a lighting system according to embodiment 1. The lighting system includes a lighting device 100 and a dimmer 61. The lighting device 100 includes an LED module 11 including a plurality of LEDs 11a, a lighting device 12 that lights up the LED module 11, and a dimming interface (I / F) circuit 62 that receives a signal from the dimmer 61. The LED module 11 corresponds to a light source having the LEDs 11a.

[0013] The lighting device 12 includes an input filter circuit 1, an input voltage detection circuit 2, a DC power supply circuit 3, a buck converter circuit 4 to which the LED module 11 is connected, a control device 50, and a temperature detection circuit 80. The control device 50 is, for example, a microcomputer.

[0014] The input filter circuit 1 includes a fuse 25 for protecting against overcurrent, an AC capacitor 26, and a diode bridge 27 for converting AC to DC. The output of the diode bridge 27 is connected to the DC power supply circuit 3. The low potential side of the output of the diode bridge 27 is connected to a ground terminal.

[0015] The input voltage detection circuit 2 is composed of resistors 21 and 22 connected in series. The input voltage detection circuit 2 is connected in parallel with a capacitor 31. The voltage division value of the resistors 21 and 22 is transmitted to the control device 50. In this way, the control device 50 detects the input voltage to the DC power supply circuit 3.

[0016] The DC power supply circuit 3 is formed of, for example, a boost chopper circuit. The DC power supply circuit 3 converts power supplied from a commercial power source and supplies a DC voltage suitable for the buck converter circuit 4. In the DC power supply circuit 3, a capacitor 31 is connected in parallel with the output of the diode bridge 13. One end of an inductor 33 is connected to the positive electrode of the capacitor 31, and the negative electrode of the capacitor 31 is connected to a ground terminal. The other end of the inductor 33 is connected to a first terminal of a switching element 32 and an anode of a diode 34. The positive electrode of an electrolytic capacitor 35 is connected to the cathode of the diode 34, and the negative electrode of the electrolytic capacitor 35 is connected to a ground terminal.

[0017] The switching element 32 is, for example, a metal-oxide-semiconductor field-effect transistor (MOSFET). When the switching element 32 is a MOSFET, the first terminal is a drain terminal, the second terminal is a source terminal, and the control terminal is a gate terminal. In the switching element 32, the first terminal is connected to the inductor 33, the second terminal is a ground terminal, and the control terminal is connected to the control circuit 30.

[0018] The control circuit 30 is a driver for switching control. The control circuit 30 drives the switching element 32 upon receiving a signal from the control device 50 based on the output voltage of the DC power supply circuit 3.

[0019] Resistors 36 and 37 are provided at the output terminal of the DC power supply circuit 3, and are used to detect the output voltage of the DC power supply circuit 3. The voltage divided by resistors 36 and 37 is input to the control device 50. Based on this detected voltage, the control device 50 turns on and off the switching element 32 via the control circuit 30 so that the output voltage of the DC power supply circuit 3 becomes a constant voltage.

[0020] In the buck converter circuit 4, a first terminal of a switching element 41 is connected to the positive electrode of the electrolytic capacitor 35, and a second terminal of the switching element 41 is connected to the cathode of a diode 42 and the positive electrode of a capacitor 43. One end of a sense resistor 44 is connected to the negative electrode of the capacitor 43, and the other end of the sense resistor 44 and the anode of the diode 42 are connected to a ground terminal.

[0021] The switching element 41 is, for example, a MOSFET. When the switching element 41 is a MOSFET, the first terminal is a drain terminal, the second terminal is a source terminal, and the control terminal is a gate terminal. In the switching element 41, the first terminal is connected to the positive electrode of the electrolytic capacitor 35, the second terminal is connected to the cathode of the diode 42, and the control terminal is connected to the control circuit 40.

[0022] The sense resistor 44 is provided in the buck converter circuit 4, and is used to detect the LED current flowing through the LED module 11. A detection voltage corresponding to the LED current from the sense resistor 44 is input to the control circuit 40, and the control circuit 40 turns on and off the switching element 41 of the buck converter circuit 4 based on this detection voltage so that the current flowing through the LED module 11 becomes a constant current. Furthermore, the voltage from the sense resistor 44 is input to the control device 50, and the control device 50 detects a current abnormality based on this detection voltage.

[0023] Resistors 45 and 46 are provided at the output terminal of the buck converter circuit 4, and are used to detect the voltage of the LED module 11. The voltage divided by resistors 45 and 46 is input to the control device 50. Based on this detected voltage, the control device 50 detects whether the LED module 11 is connected and whether there is a voltage abnormality.

[0024] The control device 50 can be realized by various types of arithmetic devices such as a processor, a microcomputer, etc. For example, various types of microcomputers provided as digital power supply control devices are already known, and these known microcomputers can be used appropriately for the control device 50. The control device 50 can also be configured by an arithmetic device such as a DSP (Digital Signal Processor). The control device 50 may be configured by multiple arithmetic devices.

[0025] In this embodiment, the control device 50 shown in Fig. 1 as an example includes a processing device 50a, a storage unit 50b, an A / D conversion circuit 50c, a temperature detection unit 50d, and an annunciation unit 50e. The control device 50 outputs a PWM signal that controls the control circuit 30 and the control circuit 40. The storage unit 50b is, for example, a non-volatile memory. The storage unit 50b stores a calculation program to be executed by the processing device 50a and various data used in the calculation. Data can be written to and read from the storage unit 50b from the outside.

[0026] The following voltages are input to the control device 50: Voltage according to the rectified voltage of the AC power divided by resistors 21 and 22 Voltage according to the output voltage of the DC power supply circuit 3 divided by resistors 36 and 37 A voltage generated across the sense resistor 44 according to the output current of the DC power supply circuit 3 Voltage according to the output voltage of the buck converter circuit 4 divided by resistors 45 and 46 Voltage according to the temperature detected by the thermistor 82, which is a temperature detection component These voltage values ​​are converted into digital values ​​by the A / D conversion circuit 50c, and the digital values ​​are used by the processing device 50a for arithmetic processing.

[0027] The processing device 50a of the control device 50 performs constant voltage control by adjusting the on-time of the switching element 32 in accordance with the output voltage of the DC power supply circuit 3 divided by resistors 36 and 37 so that the output voltage matches a target voltage previously set in the memory unit 50b.

[0028] Further, a dimming command value from a dimmer 61 is input to the control device 50 via a dimming interface (I / F) circuit 62. That is, the dimmer 61 instructs the control device 50 of the dimming rate of the LED module 11. The control circuit 40 adjusts the on-time of the switching element 41 based on the current detected by the sense resistor 44 so that the current flowing through the LED module 11 coincides with a target current determined based on the dimming command value.

[0029] The temperature detection circuit 80 is configured with a circuit in which a thermistor 82 as a temperature detection component and a resistor 81 are connected in series. A divided voltage of the thermistor 82 and resistor 81 is input to the control device 50. The temperature detection unit 50d of the control device 50 calculates the temperature based on the detected voltage of the temperature detection circuit 80, and the processing device 50a estimates the life of the lighting device 100 from the calculated temperature. Note that hereinafter, the life of the lighting device 100 may be referred to as the life of the light source.

[0030] The calculated life span is transmitted by the notification unit 50e to an external device, such as the dimmer 61, via the dimming interface (I / F) circuit 62, and is communicated to the user when necessary. In this manner, the calculated life span information is notified to, for example, the dimmer 61 by the notification unit 50e. Note that the life span information may be notified to the outside by a means other than the notification to the dimmer 61.

[0031] The thermistor 82 is desirably disposed near the LED module 11 so as to detect the temperature of the LED module 11. The location of the thermistor 82 is not limited to this. For example, the thermistor 82 may be mounted on the dimmer 61.

[0032] Next, a method for calculating the life span will be described. First, a method for detecting temperature by the temperature detection circuit 80 will be described. The voltage of the thermistor 82 is detected by the temperature detection unit 50d of the control device 50. The temperature detection unit 50d may detect the voltage of thermistor 82 at a constant cycle, or may detect it at a timing when an external instruction is received. The voltage of thermistor 82 can be expressed, for example, by the following formula (1). For this reason, such a formula may be stored in advance in the storage unit 50b of the control device 50, and the temperature detection unit 50d may calculate the detected temperature Tn [°C] by substituting the detected voltage value Vtin into formula (1).

[0033]

number

[0034] Here, Tn [° C.] is the detected temperature, B is the Boltzmann constant, R1 is the voltage dividing resistance value, R0 is the thermistor resistance value, Vcc is the constant voltage value, and Vtin is the detected voltage value.

[0035] The temperature detector 50d of the control device 50 may detect the junction temperature of the LED 11a. If the thermistor 82 is installed away from the LED module 11, the current flowing through the LED module 11 may cause the detection value of the thermistor 82 to change with respect to the temperature of the LED module 11. Therefore, the temperature detector 50d detects the junction temperature of the LED Tj The temperature detection unit 50d can calculate the junction temperature using, for example, the dimming rate of the LED module 11. The junction temperature can be expressed by the following formula (2) using the dimming rate.

[0036]

number

[0037] Here, the LED Tj is the LED junction temperature, DIM is the dimming rate, and A and B are coefficients.

[0038] Incidentally, the power of the lighting device 100 is determined by the conversion efficiency, the VF of the LED module 11, and the current flowing through the LED module 11. The VF of the LED module 11 is determined by the connected LED 11a. Also, the current flowing through the LED module 11 is determined by the constant current control value of the buck converter circuit 4. The constant current control value is determined by the dimming rate DIM. For this reason, if replacement of the LED module 11 after the lighting device 100 is installed in a building or the like is not taken into consideration, the power of the lighting device 100 is determined by the dimming rate DIM.

[0039] From the above, the estimated value of the LED junction temperature may be made dependent on the power of the lighting device 100. In other words, the temperature detection unit 50d may calculate the junction temperature using the power consumption of the LED module 11. The temperature detection unit 50d may also calculate the junction temperature using the power consumption of the lighting device 12 or the lighting device 100.

[0040] Next, the temperature detection unit 50d calculates the average temperature of the LED module 11 from the calculated temperature of the LED module 11. The temperature detection unit 50d may calculate the average value from the temperature detected by the temperature detection circuit 80, or may calculate the average value from the junction temperature of the LED 11a. Here, an example of converting the junction temperature of the LED 11a to the average value will be described.

[0041] The storage unit 50b stores in advance the formula (3) for calculating the latest average value. The temperature detection unit 50d calculates the average value using the formula (3) every time it acquires the junction temperature.

[0042]

number

[0043] Here, A is the average temperature up to now, N is the number of times the temperature has been acquired, T is the temperature acquired this time, and Tavg is the latest average temperature of the LED module 11. Here, the junction temperature is used as the temperature, but the average value may be calculated from the temperature detected by the temperature detection circuit 80 and formula (3).

[0044] Figures 2 and 3 are diagrams showing examples of the instantaneous and average temperatures of a light source. The average temperatures in Figures 2 and 3 are calculated using formula (3). By constantly calculating the latest average value, the average value will draw a smoother curve than the instantaneous value.

[0045] Next, the processing device 50a of the control device 50 calculates the life information of the LED module 11 from the calculated average temperature value of the LED module 11 and the accumulated lighting time of the LED module 11. The life of the lighting device 100 can be calculated by utilizing the luminous flux attenuation characteristics of the LED. In general, the Arrhenius law holds true for the relationship between life and temperature. Here, considering that the formula will be incorporated into a program, it is desirable to make the parameters into coefficients in order to minimize the data. For example, the following formula (4) can be stored in the storage unit 50b in advance, and the coefficients α and β can be changed according to the LED to be used.

[0046]

number

[0047] Here, α and β are coefficients, T is the average value of the temperature of the light source, and L2 is the life of the lighting device 100.

[0048] Finally, the processing device 50a calculates the current remaining life using the life L2 of the lighting device 100. If the cumulative lighting time counted by the control device 50 is L1, the current remaining life L can be calculated by subtraction equation (5). L = L2 - L1 … (5) The accumulated lighting time is stored in, for example, the storage unit 50b. It is also advisable to store the formula (5) in advance in the storage unit 50b.

[0049] In this way, the life information can be calculated using an exponential function having an exponent determined by the coefficients α and β determined by the type of the LED 11a and the average temperature of the LED module 11.

[0050] Next, a method of transmitting the estimated lifespan to the outside will be described. A lifespan check command is input to the dimmer 61 by an operation by a user or administrator, or by a signal transmitted periodically. The lifespan check command input from the dimmer 61 is recognized by the control device 50 via the dimming interface (I / F) circuit 62. The processing device 50a of the control device 50 calculates lifespan information in response to the lifespan check command. That is, the current remaining lifespan L is calculated by the above calculation method. The current remaining lifespan L is responded to the dimmer 61 from the control device 50 via the dimming interface (I / F) circuit 62.

[0051] The current remaining life L that is returned may be displayed as a specific numerical value on the screen of a personal computer, etc. If the remaining life L indicates the time to replace the LED module 11 or the lighting device 100, error information may be notified to a user or a manager.

[0052] According to this embodiment, the lifespan information of the light source is calculated using the average temperature of the light source, and the lifespan information is notified to the outside. Therefore, the lifespan information can be notified without being affected by temporary changes in temperature. In other words, the deterioration state of the light source can be accurately grasped and the lifespan information can be notified to the outside without being affected by temporary changes in temperature due to weather or season. This makes it possible to encourage replacement of the lighting device 100 at the optimal time.

[0053] The average value of the temperature of the light source may be the average value for the entire period from the installation of the lighting device 100 to the present, or may be the average value for any predetermined period. Furthermore, the control device 50 may acquire the temperature and calculate the latest average value of the temperature of the LED module 11 at the timing when the life confirmation instruction is received. Furthermore, the control device 50 may periodically detect the temperature and update the average value.

[0054] In the present embodiment, the control device 50 has been described as a part of the lighting device 100. In this manner, the lighting system of the present embodiment may be configured as one lighting device 100. Also, the control device 50 for calculating the life information may be provided outside the lighting device 100. In other words, the lighting system may be configured from the lighting device 100 having a light source, and the control device 50 provided outside the lighting device 100 and configured to calculate the life information.

[0055] The technical features described in this embodiment may be used in appropriate combination.

[0056] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) A light source having an LED; a control device that calculates life information of the light source from an average value of the temperature of the light source and an accumulated lighting time of the light source, and notifies the life information to an outside; A lighting system comprising: (Appendix 2) The lighting system of claim 1, wherein the control device calculates the average value from the junction temperature of the LED. (Appendix 3) The lighting system described in Appendix 2, wherein the control device calculates the junction temperature using power consumption of the light source. (Appendix 4) The lighting system according to claim 2, wherein the control device calculates the junction temperature using a dimming rate of the light source. (Appendix 5) Equipped with a temperature detection circuit, The lighting system according to claim 1, wherein the control device calculates the average value from the temperature detected by the temperature detection circuit. (Appendix 6) The lighting system described in any one of Appendices 1 to 5, characterized in that the life information is calculated using an exponential function having an exponent determined by a coefficient determined by the type of the LED and the average value. (Appendix 7) a dimmer that instructs the control device on a dimming rate of the light source; The lighting system according to any one of claims 1 to 6, wherein the life information is notified to the dimmer. (Appendix 8) The lighting system described in Appendix 7, characterized in that when a life confirmation instruction is input from the dimmer, the control device calculates the life information. [Explanation of symbols]

[0057] 1 input filter circuit, 2 input voltage detection circuit, 3 DC power supply circuit, 4 buck converter circuit, 11 LED module, 12 lighting device, 13 diode bridge, 21 resistor, 22 resistor, 25 fuse, 26 capacitor, 27 diode bridge, 30 control circuit, 31 capacitor, 32 switching element, 33 inductor, 34 diode, 35 electrolytic capacitor, 36 resistor, 37 resistor, 40 control circuit, 41 switching element, 42 diode, 43 capacitor, 44 sense resistor, 45 resistor, 46 resistor, 50 control device, 50a processing device, 50b memory unit, 50c A / D conversion circuit, 50d temperature detection unit, 50e notification unit, 61 dimmer, 62 dimming interface (I / F) circuit, 80 temperature detection circuit, 81 resistor, 82 thermistor, 100 lighting device

Claims

1. A light source having an LED; a control device that calculates life information of the light source from an average value of the temperature of the light source and an accumulated lighting time of the light source, and notifies the life information to an outside; A lighting system comprising:

2. The lighting system according to claim 1 , wherein the control device calculates the average value from a junction temperature of the LED.

3. The lighting system according to claim 2 , wherein the control device calculates the junction temperature using power consumption of the light source.

4. The lighting system according to claim 2 , wherein the control device calculates the junction temperature using a dimming rate of the light source.

5. Equipped with a temperature detection circuit, The lighting system according to claim 1 , wherein the control device calculates the average value from the temperature detected by the temperature detection circuit.

6. 6. The lighting system according to claim 1, wherein the lifetime information is calculated using an exponential function having an exponent determined by a coefficient determined by a type of the LED and the average value.

7. a dimmer that instructs the control device on a dimming rate of the light source; The lighting system according to claim 1 , wherein the life information is notified to the dimmer.

8. The lighting system according to claim 7 , wherein the control device calculates the life information when a life confirmation command is input from the dimmer.

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