Technical field

The present inventive concept relates to the control of an illumination system.

Background of the invention

Chronobiology, which is a field of biology that studies timing (e.g., periodic) processes and phenomena in living organisms, is becoming increasingly more important for understanding human physiology. For example, the circadian rhythm is an internal process of living organisms (e.g. humans) that regulates the sleep-wake cycle. An important part of chronobiology is the study of the impact of light on living organisms. It has, for example, been found that exposing a person to bright light in the evening can postpone the time that person falls asleep. Recent studies have found that light can also affect a person’s alertness and performance. It has been found that the effect of light at a certain time of day is not only instant, as it also depends on the individual’s prior exposure to light, e.g., earlier that day. For instance, in case an individual has been exposed to bright light in the morning (e.g., light similar to that of a bright summer’s morning), the effect of bright light during the afternoon is typically less than if the same person had spent the morning being exposed to light of lower illuminance (e.g. artificial light inside an office). Thus, there incentives to adapt the lighting environment for individuals in order to improve their wellbeing.

However, producing bright light for exposing individuals is often associated with high energy consumption. For instance, the energy consumption of light sources typically scales linearly with brightness of emitted light. Therefore, the associated energy need may become high. This can be problematic, especially since the electric power production is becoming more reliant on weather-dependent energy sources such as wind and solar. A benefit of such sources are that they are renewable and typically have a reduced impact on the environment. However, due to their weatherdependence, it is often a challenge to control the energy production using such sources to meet the demand for electrical power.

Hence, there exists a need for improvement within the art.

Summary of the invention

It is an object to, at least partly, mitigate, alleviate, or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination and solve at least the above-mentioned problem.

According to a first aspect a method for controlling a illumination system comprising one or more light sources is provided. The method comprising: obtaining, for a future time period, a temporally resolved overall available electric power distribution of an electrical energy grid to which the illumination system is connected; obtaining, for the future time period, a temporally resolved target light setting comprising data pertaining to a temporally resolved intensity and correlated color temperature of light to be emitted by the one or more light sources; determining, from the temporally resolved target light setting, a temporally resolved electric power consumption distribution of the one or more light sources; redistributing the temporally resolved electric power consumption distribution such that a difference between a redistributed temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution is relatively smaller than a difference between the temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution; determining, from the redistributed temporally resolved electric power consumption distribution, a redistributed temporally resolved light setting for the future time period; and controlling, during the future time period, the one or more light sources in accordance with the adjusted temporally resolved light setting.

Within the context of this disclosure, the wording “temporally resolved overall available electric power distribution” should be construed as a temporal distribution of available electrical power. For instance, it may be a time-resolved distribution of estimated available electrical power for an upcoming time period.

Within the context of this disclosure, the wording “temporally resolved target light setting” should be construed as planned time-resolved settings for one or more light sources. The settings comprise information on intensities and correlated color temperatures of light to be emitted by the one or more light source for an upcoming time period.

Within the context of this disclosure, the wording “temporally resolved electric power consumption distribution” should be construed as a distribution comprising time-resolved power consumption of the one or more light sources for an upcoming time period given that the light sources are controlled according to the target light setting during that upcoming time period. The temporally resolved electric power consumption distribution may be estimated from the temporally resolved target light setting. The distribution may comprise further power consumption of other, related, devices of the illumination system, such as a control engine configured to control the illumination system.

Within the context of this disclosure, the “difference” between a first distribution (e.g., the redistributed temporally resolved electric power consumption distribution, or the temporally resolved electric power consumption distribution) and a second distribution (e.g., the temporally resolved overall available electric power distribution) should be construed as a degree of dissimilarity of the first and second distributions. A larger difference between the first and second distributions is indicative of a larger dissimilarity of the first and second distributions (and vice versa). The skilled person realizes that the difference between the first and second distributions may be determined in various manners. The difference may be a squared mathematical difference (i.e., the result of a subtraction) between the first and second distributions at a specific time (assuming that the first and second distributions are distributions over time). For instance, the squared mathematical difference may be integrated over the future time period, whereby an overall indication of the difference between the first and second distributions may be determined. As a further example, the difference may be determined as a Kullback-Leibler divergence between the first and second distributions.

By means of the present inventive concept, the one or more light sources is controlled such that power consumption of the illumination system is more in line with the available electric power of the electrical power grid. Put differently, the power consumption of the illumination system may be higher when the available electrical power is higher, and the power consumption of the illumination system may be lower when the available electrical power is lower. This, in turn, reduces an associated load of the illumination system on the electrical power grid to which it is connected.

Typically, an economical cost associated with electric power consumption is related to the available electric power. For instance, it is common that the price of electric power is higher when the available electric power is lower, and vice versa. Hence, the present inventive concept may allow for an illumination system which is more cost-effective during use.

The temporally resolved electric power distribution may be redistributed on a condition that an accumulated intensity and correlated color temperature of light to be emitted according to the redistributed temporally resolved light setting is maintained as compared with an accumulated intensity and correlated color temperature of light to be emitted according to the temporally resolved target light setting.

An associated advantage is that the one or more light sources may, over time, emit light according to the target light setting, while reducing the associated load of the illumination system on the electrical power grid to which it is connected.

A further associated advantage is that an illumination system which is capable of exposing, over time, individuals to light according to the target light setting while reducing the associated load of the illumination system on the electrical power grid to which it is connected.

The method may further comprise: normalizing the temporally resolved overall available electric power distribution; and normalizing the temporally resolved electric power consumption distribution.

The normalizing the temporally resolved overall available electric power distribution, and the normalizing the temporally resolved electric power consumption distribution may be prior to the redistributing the temporally resolved electric power consumption distribution.

An associated advantage is that the difference may be determined using the normalized distributions, whereby a less complex implementation of the redistributing the temporally resolved electric power consumption distribution may be allowed.

The redistributing the temporally resolved electric power consumption distribution may comprise temporally shifting the temporally resolved electric power consumption distribution.

An associated advantage is that a less complex redistributing the temporally resolved electric power consumption distribution may be allowed.

The future time period may be a time period of 1-10 hours.

According to a second aspect a control engine configured to control an illumination system comprising one or more light sources is provided. The control engine comprising circuitry configured to execute: a first obtaining function configured to obtain, for a future time period, a temporally resolved overall available electric power distribution of an electrical energy grid to which the illumination system is connected; a second obtaining function configured to obtain, for the future time period, a temporally resolved target light setting comprising data pertaining to a temporally resolved intensity and correlated color temperature of light to be emitted by the one or more light sources; a first determining function configured to determine, from the temporally resolved target light setting, a temporally resolved electric power consumption distribution of the one or more light sources; a redistributing function configured to redistribute the temporally resolved electric power consumption distribution such that a difference between a redistributed temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution is relatively smaller than a difference between the temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution; a second determining function configured to determine, from the redistributed temporally resolved electric power consumption distribution, a redistributed temporally resolved light setting for the future time period; and a controlling function configured to control, during the future time period, the one or more light sources in accordance with the adjusted temporally resolved light setting.

The redistributing function may be configured to redistribute the temporally resolved electric power distribution on a condition that an accumulated intensity and correlated color temperature of light to be emitted according to the redistributed temporally resolved light setting is maintained as compared with an accumulated intensity and correlated color temperature of light to be emitted according to the temporally resolved target light setting.

The circuitry may be further configured to execute: a first normalizing function configured to normalize the temporally resolved overall available electric power distribution; and a second normalizing function configured to normalize the temporally resolved electric power consumption distribution.

The circuitry may be configured to execute the first normalizing function and the second normalizing function prior to the redistributing function.

The redistributing function may be configured to temporally shift the temporally resolved electric power consumption distribution.

The future time period may be a time period of 1-10 hours.

The above-mentioned features of the first aspect, when applicable, apply to this second aspect as well. In order to avoid undue repetition, reference is made to the above.

According to a third aspect an illumination system is provided. The illumination system comprising: one or more light sources; and a control engine according to the second aspect.

The above-mentioned features of the first and/or second aspects, when applicable, apply to this third aspect as well. In order to avoid undue repetition, reference is made to the above.

According to a fourth aspect a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium comprising program code portions which, when executed on a device having processing capabilities, performs the method according to the first aspect.

The above-mentioned features of the first, second, and/or third aspects, when applicable, apply to this fourth aspect as well. In order to avoid undue repetition, reference is made to the above.

A further scope of applicability of the present disclosure will become apparent from the detailed description given below. However, it should be understood that the detailed description and specific examples, while indicating preferred variants of the present inventive concept, are given by way of illustration only, since various changes and modifications within the scope of the inventive concept will become apparent to those skilled in the art from this detailed description.

Hence, it is to be understood that this inventive concept is not limited to the particular steps of the methods described or component parts of the systems described as such method and system may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only and is not intended to be limiting. It must be noted that, as used in the specification and the appended claim, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. Thus, for example, reference to “a unit” or “the unit” may include several devices, and the like.

Furthermore, the words “comprising”, “including”, “containing” and similar wordings do not exclude other elements or steps.

Brief description of the drawings

The above and other aspects of the present inventive concept will now be described in more detail, with reference to appended drawings showing variants of the inventive concept. The figures should not be considered limiting the inventive concept to the specific variant; instead they are used for explaining and understanding the inventive concept. As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of variants of the present inventive concept. Like reference numerals refer to like elements throughout.

Figure 1A illustrates an illumination system comprising three light sources and a control engine.

Figure 1 B illustrates the control engine of Fig. 1 .

Figure 2 is a block scheme of a method for controlling the illumination system of Fig. 1A.

Figure 3 illustrates a non-transitory computer-readable storage medium.

Figure 4A illustrates a temporally resolved power consumption distribution (solid line) and a temporally resolved overall available power distribution (dashed line).

Figure 4B illustrates a redistributed temporally resolved power consumption distribution (solid line) and a temporally resolved overall available power distribution (dashed line).

Figure 4C illustrates a redistributed temporally resolved power consumption distribution (solid line) and a temporally resolved overall available power distribution (dashed line).

Detailed description

The present inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred variants of the inventive concept are shown. This inventive concept may, however, be implemented in many different forms and should not be construed as limited to the variants set forth herein; rather, these variants are provided for thoroughness and completeness, and fully convey the scope of the present inventive concept to the skilled person.

Figure 1A illustrates an illumination system 10. The illumination system 10 comprises one or more light sources 160, 162, 164, and a control engine 100. The control engine 100 of the illumination system 10 is illustrated in Fig. 1 B. The illumination system 10 may be configured to serve a room, as in the example of Fig. 1A. However, it is to be understood that the illumination system 10 may be configured to serve a plurality of rooms. The plurality of rooms may be a zone.

In the example of Fig. 1A, the one or more light sources 160, 162, 164 comprises a first lamp 160, a second lamp 162, and a third lamp 164. The first lamp 160 and the second lamp 162 may be arranged at a ceiling 12. The third lamp 164 may be arranged on a table 14. The one or more light sources 160, 162, 164 may be adjustable light sources. By adjustable, it is here meant that an intensity and a correlated color temperature of light emitted by a light source is adjustable. In the example of Fig. 1A, an individual 170, in this case a person, is present.

The control engine 100 is configured to control the illumination system 10. Put differently, the control engine 100 may be configured to control one or more functions and/or devices of the illumination system 10. For instance, the control engine 100 may be configured to control the one or more light sources 160, 162, 164 of the illumination system 10. The control engine 100 may be configured to communicate with the one or more light sources 160, 162, 164 via a wired and/or a wireless connection. This is exemplified in Fig. 1 A by the first lamp 160 and the second lamp 162 being configured to communicate with the control engine 100 via wired connections 102, and the third lamp 164 being configured to communicate with the control engine 100 via a wireless connection 104. The skilled person would be aware of suitable wired connections and wireless connections. Non-limiting examples of wired connections comprises ethernet, USB, Firewire, power-line communication, etc. Non-limiting examples of wireless connections comprises Wi-Fi, Li-Fi, NFC, Bluetooth, cellular connections (e.g., 2G-5G, etc.) etc.

As is illustrated in Fig. 1 B, the control engine 100 comprises circuitry 110 configured to execute a first obtaining function 1202, a second obtaining function 1204, a first determining function 1206, a redistributing function 1208, a second determining function 1210, and a controlling function 1212. As is illustrated in the example of Fig. 1 B, the circuitry 110 may be further configured to execute one or more of a first normalizing function 1214 and a second normalizing function 1216. As is illustrated in the example of Fig. 1 B, the circuitry 110 may comprise one or more of a memory 120, a processing unit 130, a transceiver 140, and a data bus 150. Even though not explicitly illustrated in Fig. 1A or Fig. 1 B, the control engine 100 may comprise input devices such as one or more of a keyboard, a mouse, and a touchscreen. The control engine 100 may, as illustrated in the example of Fig. 1A, be arranged locally, i.e. , in the vicinity of the space which the illumination system 10 is configured to serve. Alternatively, or additionally, the control engine 100 may be implemented as a cloud server. The processing unit 130 may comprise one or more of a central processing unit (CPU), a graphical processing unit (GPU), a microcontroller, and a microprocessor. The memory 120 may comprise a non-transitory computer-readable storage medium. The memory 120 may comprise one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random-access memory (RAM), or another suitable device. In a typical arrangement, the memory 120 may comprise a non-volatile memory for long term data storage and a volatile memory that functions as system memory for the control engine 100. The memory 120, the processing unit 130, and the transceiver 140 may be configured to communicate via the data bus 150. The memory 120 may exchange data with the processing unit 130 and/or the transceiver 140 via the data bus 150. The transceiver 140 may be configured to communicate with other devices. The transceiver 140 may be configured to transmit data and/or signals from the circuitry 110 and/or the control server. The transceiver 140 may be configured to receive data and/or signals. Put differently, the circuitry 110 may be configured to transmit and receive data and/or signals via the transceiver 140. The one or more light sources 160, 162, 164 may communicate with one or more of the memory 120, the processing unit 130, and the transceiver 140 via the data bus 150. Alternatively, or additionally, the one or more light sources 160, 162, 164 may communicate with the memory 120 and/or processing unit 130 via the transceiver 140. The circuitry 110 may be configured to perform one or more functions of the control engine 100. As is illustrated in Fig. 1 B, the memory 120 may store one or more program code portions 1202, 1204, 1206, 1208, 1210, 1212, 1214, 1216 corresponding to one or more functions. The processing unit 130 may be configured to execute one or more program code portions 1202, 1204, 1206, 1208, 1210, 1212, 1214, 1216 stored on the memory 120, in order to carry out functions and/or operations of the control engine 100. Functions and/or operations of the circuitry 110 may be implemented in the form of executable logic routines (e.g., lines of code, software programs, etc.) that are stored on the memory 120 and may be executed by the processing unit 130. Put differently, when it is stated that the circuitry 110 is configured to execute a specific function, the processing unit 130 of the circuitry 110 may be configured to execute one or more program code portions 1202, 1204, 1206, 1208, 1210, 1212, 1214, 1216 stored on the memory 120, wherein the one or more program code portions 1202, 1204, 1206, 1208, 1210, 1212, 1214, 1216 correspond to the specific function. Furthermore, the functions and/or operations of the circuitry 110 may be a stand-alone software application or form a part of a software application that carries out additional tasks related to the circuitry 110. The described functions and operations may be considered a method that the corresponding device is configured to carry out, such as the method 20 discussed below in connection with Fig. 2. Also, while the described functions and operations may be implemented in software, such functionality may as well be carried out via dedicated hardware or firmware, or some combination of one or more of hardware, firmware, and software.

The first obtaining function 1202 is configured to obtain, for a future time period, a temporally resolved overall available electric power distribution of an electrical energy grid to which the illumination system 10 is connected. Within the context of this disclosure, the wording “temporally resolved overall available electric power distribution” should be construed as a temporal distribution of available electrical power. For instance, it may be a time- resolved distribution of estimated available electrical power for an upcoming time period. The first obtaining function 1202 may be configured to obtain the temporally resolved overall available electric power distribution via the transceiver 140 of the circuitry 110. The temporally resolved overall available electric power distribution may be determined from a planned electrical production. For instance, depending on a weather forecast, the electrical production from wind and solar power plants may be estimated. Further, electrical production from other types of power plants (e.g., hydropower, nuclear, etc.) may be estimated in order to compensate for the electrical production from wind and solar. The first obtaining function 1202 may be configured to obtain the temporally resolved overall available electric power distribution via a network, e.g., the internet. The temporally resolved overall available electric power distribution may be associated with the electrical grid to which the illumination system 10 is connected. For example, the temporally resolved overall available electric power distribution may be provided by an owner and/or operator of the associated electrical grid.

The future time period may be a time period of 1-10 hours. However, it is to be understood that the temporally resolved overall available electric power distribution may comprise information of overall available electric power for a longer time period than the future time period, and a portion of that information corresponding to the future time period may be used.

The second obtaining function 1204 is configured to obtain, for the future time period, a temporally resolved target light setting comprising data pertaining to a temporally resolved intensity and correlated color temperature of light to be emitted by the one or more light sources 160, 162, 164. Within the context of this disclosure, the wording “temporally resolved target light setting” should be construed as planned time-resolved settings for one or more light sources 160, 162, 164. The settings comprise information on intensities and correlated color temperatures of light to be emitted by the one or more light source for an upcoming time period. The second obtaining function 1204 may be configured to obtain the temporally resolved target light setting via the transceiver 140 of the circuitry 110. The temporally resolved target light setting may be obtained via a network, e.g., the internet. The temporally resolved target light setting may be settings for a planned lighting environment in the space which the illumination system 10 is configured to serve. The temporally resolved target light setting may be determined from one or more target light profiles associated with individuals 170 present (or planned to be present) in the space which the illumination system 10 is configured to serve. Each target light profile may be associated with an individual 170. Each target light profile may comprise temporally resolved information associated with an intensity and correlated color temperature of light to which the associated individual 170 is to be exposed to. For instance, each target light profile may comprise information for a time period which is equal to, or longer, than the future time period. In case several individuals 170 are present (or planned to be present) in the space served by illumination system 10, the temporally resolved target light setting may be determined from one or more of the associated target light profiles. For instance, each target light profile may be associated with a priority, and the target light setting may be determined from the target light profile having the highest priority. Alternatively, or additionally, the target light setting may be determined from an average of one or more of the associated target light profiles. The average may be a weighted average, e.g., using the associated priorities as weights.

The first determining function 1206 is configured to determine, from the temporally resolved target light setting, a temporally resolved electric power consumption distribution of the one or more light sources 160, 162, 164. Within the context of this disclosure, the wording “temporally resolved electric power consumption distribution” should be construed as a distribution comprising time-resolved power consumption of the one or more light sources 160, 162, 164 for an upcoming time period given that the light sources are controlled according to the target light setting during that upcoming time period. The temporally resolved electric power consumption distribution may be estimated from the temporally resolved target light setting. For instance, by knowing the intensity and the correlated color temperature of light to be emitted by the one or more light sources 160, 162, 164 of the illumination system 10 over the future time period, the associated electric power consumption may be determined. Hence, the temporally resolved electric power consumption distribution may be determined or estimated. The distribution may comprise further power consumption of other, related, devices of the illumination system 10, such as the control engine 100. Typically, the electric power consumption scales linearly with the intensity of light emitted by the one or more light sources 160, 162, 164. Thus, a higher intensity according to the temporally resolved target light setting may result in a higher corresponding electric power consumption. Further, a higher correlated color temperature of light emitted by the one or more light sources 160, 162, 164 may result in a higher corresponding electric power consumption. The first determining function 1206 may use information on power consumption associated with the one or more light sources 160, 162, 164 when determining the temporally resolved electric power consumption distribution. The information on power consumption associated with the one or more light sources 160, 162, 164 may be measured during a calibration of the illumination system 10, i.e., the power consumption of the one or more light sources 160, 162, 164 as functions of intensity and correlated color temperature may be measured. Alternatively, or additionally, such information may be supplied by a manufacturer of the one or more light sources 160, 162, 164. The information on power consumption associated with the one or more light sources 160, 162, 164 may be stored on the memory 120 of the circuitry 110, and the first determining function 1206 may be configured to retrieve that information from the memory 120.

The redistributing function 1208 is configured to redistribute the temporally resolved electric power consumption distribution such that a difference between a redistributed temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution is relatively smaller than a difference between the temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution. Here, the “difference” between the redistributed temporally resolved electric power consumption distribution (or the temporally resolved electric power consumption distribution) and the temporally resolved overall available electric power distribution should be construed as a degree of dissimilarity of the two distributions. A larger difference is indicative of a larger dissimilarity of the two distributions (and vice versa). The skilled person realizes that the difference may be determined in different manners. For instance, the difference may be a squared mathematical difference (i.e., the result of a subtraction) between the distributions at a specific time (e.g., a specific time of day). For instance, the squared mathematical difference between the distributions may be integrated (or summed) over the future time period, whereby an overall indication of the difference between the first and second distributions may be determined. The redistributing function 1208 may be configured to redistribute the temporally resolved electric power consumption distribution such that a similarity between the redistributed temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution is relatively larger than a similarity between the temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution. Here, “similarity” between the redistributed temporally resolved electric power consumption distribution (or the temporally resolved electric power consumption distribution) and the temporally resolved overall available electric power distribution should be construed as a degree of similarity of the two distributions. The redistributing function 1208 may be configured to redistribute the temporally resolved electric power consumption distribution such that it is more similar to the temporally resolved overall available electric power distribution after the redistribution (i.e. , the redistributed temporally resolved electric power consumption distribution) than prior to the redistribution (i.e., the temporally resolved electric power consumption distribution).

The redistributing function 1208 may be configured to redistribute the temporally resolved electric power distribution on a condition that an accumulated intensity and correlated color temperature of light to be emitted according to the redistributed temporally resolved light setting is maintained as compared with an accumulated intensity and correlated color temperature of light to be emitted according to the temporally resolved target light setting. The intensity and/or the correlated color temperature may be accumulated over the future time period. Put differently, according to the redistributed temporally resolved light setting, the one or more light sources 160, 162, 164 may over the future time period emit the same light dose (i.e., accumulated intensity and correlated color temperature of light) as according to the temporally resolved target light setting.

The redistributing function 1208 may be configured to temporally shift the temporally resolved electric power consumption distribution. The temporally resolved electric power consumption distribution may be shifted to form the redistributed temporally resolved electric power consumption distribution. Put differently, the redistributed temporally resolved electric power consumption distribution may be the temporally resolved electric power consumption distribution being temporally shifted. Hence, an overall shape of the temporally resolved power consumption distribution may be maintained, while the difference between redistributed temporally resolved power consumption distribution may be decreased. The temporal shift may be towards an earlier time of day or a later time of day. Whether the temporal shift is towards an earlier time of day or a later time of day may be chosen depending on which of the two temporal shifts results in a smaller difference between the redistributed temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution. The redistributing function 1208 may be configured to pad (e.g., by adding information) portions of the redistributed temporally resolved electric power consumption distribution. This since the redistributed temporally resolved electric power consumption distribution may, after redistributing (e.g., shifting) the temporally resolved electric power consumption distribution, lack data on electric power consumption for portions of the redistributed temporally resolved electric power consumption distribution. The redistributing function 1208 may be configured to use temporally resolved electric power consumption data from a time period prior to the future time period. For instance, the temporally resolved electric power consumption data from the time period prior to the future time period may be padded (e.g., by being added) into the portion of the redistributed temporally resolved electric power consumption distribution. Instead of using this data directly (i.e., by padding), the redistributing function 1208 may be configured to determine an average for the time period lacking data or to determine electric power consumption data that connects electric power consumption of a time period prior to the future time period to the shifted temporally resolved electric power consumption distribution. The data connecting the time period prior to the future time period and the shifted temporally resolved electric power consumption distribution may be a linear function, a non-linear function, or a combination of the two.

The circuitry 110 may be configured to execute the first normalizing function 1214 and the second normalizing function 1216 prior to the redistributing function 1208. The first normalizing function 1214 may be configured to normalize the temporally resolved overall available electric power distribution. The second normalizing function 1216 may be configured to normalize the temporally resolved electric power consumption distribution. After normalization, the distributions may comprise normalized values. The first normalizing function 1214 and the second normalizing function 1216 may be configured to keep track of normalization constants. For instance, the first normalizing function 1214 and the second normalizing function 1216 may be configured to store the normalization constants on the memory 120 of the circuitry 110. By keeping track of the normalization constants, the normalized distributions may be reversed. Put differently, the normalized values of the distributions may be reversed to their initial units/dimensions. The normalization constants may depend on a type of normalization used. For instance, for m in-max feature scaling, the normalization constants may be the maximum value and minimum value X _min in each distribution. A normalized distribution X’ of a distribution X may be determined according to:

This normalization may be reversed by:

X = (X _max - X _min ) + X _min

In particular, the normalization may be reversed after the normalized distribution X’ has been redistributed by the redistributing function 1208. By normalizing the temporally resolved overall available electric power distribution and the temporally resolved electric power consumption distribution, the two distributions may be compared in a less complex manner.

This since the two distributions may be dimensionless and/or that the two distributions have the same maximum value (i.e., 1 ) and the same minimum value (i.e., 0).

The second determining function 1210 is configured to determine, from the redistributed temporally resolved electric power consumption distribution, a redistributed temporally resolved light setting for the future time period. In case the temporally resolved electric power consumption distribution comprises normalized values (i.e., in case the circuitry 110 has executed the second normalizing function 1216), the second determining function 1210 may be configured to retrieve the normalization constants from the second normalizing function 1216 and/or from the memory 120. The second determining function 1210 may thereby reverse the normalization of the redistributed temporally resolved electric power consumption distribution. The second determining function 1210 may be configured to determine the redistributed temporally resolved light setting from the redistributed temporally resolved electric power consumption distribution in the same manner (but reversed) as the first determining function 1206.

The controlling function 1212 is configured to control, during the future time period, the one or more light sources 160, 162, 164 in accordance with the adjusted temporally resolved light setting. The one or more light sources 160, 162, 164 is thereby controlled such that the power consumption of the illumination system 10 is more in line with the available electric power of the electrical power grid. Put differently, the power consumption of the illumination system 10 may be higher when the available electrical power is higher, and the power consumption of the illumination system 10 may be lower when the available electrical power is lower. This, in turn, may reduce an associated load on the electrical power grid to which the illumination system 10 is connected. Typically, an economical cost associated with electric power consumption is related to the available electric power. For instance, it is common that the price of electric power is higher when the available electric power is lower, and vice versa. Hence, the illumination system 10 may be more cost-effective during use. The controlling function 1212 may be configured to control, during the future time period, the intensity of light to be emitted by the one or more light sources 160, 162, 164 in accordance with the adjusted temporally resolved light setting, and the correlated color temperature of light to be emitted by the one or more light sources 160, 162, 164 in accordance with the temporally resolved target light setting.

Figure 4A illustrates the temporally resolved power consumption distribution (solid line in Fig. 4A) and the temporally resolved overall available electric power distribution (dashed line in Fig. 4A) for the future time period AT0. The temporally resolved power consumption distribution is determined from the temporally resolved target light setting as discussed in connection with Fig. 1A and Fig. 1 B. Further, the distributions illustrated in Fig. 4A - Fig. 4C are normalized, i.e. , the distributions comprise normalized values. However, as is seen in the example of Fig. 4C, the redistributed temporally resolved power consumption distribution (solid line in Fig. 4C) may have a maximum value larger than the maximum normalized value of the temporally resolved power consumption distribution (i.e., larger than 1 ). This may be an effect of the redistribution. Thus, the redistributed temporally resolved power consumption distribution illustrated in Fig. 4C is not normalized with respect to a maximum value and a minimum value of the redistributed temporally resolved power consumption distribution of Fig. 4C. The vertical axes in the examples of Fig. 4A - Fig. 4C represent normalized values of the respective distributions. The horizontal axes in the examples of Fig. 4A - Fig. 4C represent time T.

As is seen in Fig. 4A, the power consumption of the illumination system 10 for the future time period AT0 does not take the available power of the electric grid into account. For instance, at a first point in time T1 , the available power of the electric grid is low, while the power consumption of the illumination system 10 is high. Thus, the load on the electric grid due to the illumination system 10 is relatively high at the first point in time T1. By redistributing the temporally resolved power consumption distribution, the relatively high load at the first point in time T1 may be reduced.

In Fig. 4B, the temporally resolved power consumption distribution (solid line in Fig. 4B) is temporally shifted towards a later time of day. As is seen in this example, the difference between the redistributed temporally resolved power consumption distribution (solid line in Fig. 4B) and the temporally resolved overall available power distribution (dashed line in Fig. 4B) is smaller than the corresponding difference in Fig. 4A. For example, the load on the electric grid at the first point in time T1 is reduced for the redistributed temporally resolved power consumption distribution as compared to the example in Fig. 4A. In this specific example, the power consumption previously present at the first point in time T1 in Fig. 4A is now at a second point in time T2 in Fig. 4B. At the second point in time T2, the available power is higher, whereby the load on the electric grid is lower compared to example in Fig. 4A. However, due to the temporal shift in Fig. 4B, the redistributed temporally resolved power consumption distribution does not have data on power consumption for a first time period AT1 within the future time period ATO. As discussed in connection with Fig. 1 A and Fig. 1 B, the data on power consumption may be determined using data from a time period prior to the future time period ATO (not illustrated in Fig. 4B). Alternatively, or additionally, the data on power consumption which has been moved out of the future time period ATO may be used to pad the redistributed temporally resolved power consumption distribution. In the example of Fig. 4B, the data moved out of the future time period ATO (due to the temporal shift) is within a second time period AT2. Data within the second time period AT2 may, e.g., be moved to the first time period AT1 and thereby be used to pad the redistributed temporally resolved power consumption distribution. By temporally shifting the temporally resolved power consumption distribution, its overall shape may be maintained (possibly with smaller deviations in the first time period AT1 ). Hence, an accumulated (e.g., accumulated over the future time period ATO) light dose of light emitted by the illumination system 10 if it is controlled according to the redistributed temporally resolved light setting (determined from the redistributed temporally resolved power consumption distribution) may be similar to an accumulated light dose of light emitted by the illumination system 10 if it is controlled according to the temporally resolved target light setting (from which the temporally resolved power consumption distribution is determined).

In the example illustrated in Fig. 4C, the temporally resolved power consumption distribution is redistributed by reducing the temporally resolved power consumption distribution in a third time period AT3 in which the available power is relatively lower. This reduction is then compensated in a fourth time period AT4 within which the available power is relatively higher. By compensating the reduction in the third time period AT3 with the increase in the fourth time period AT4, the accumulated (e.g., accumulated over the future time period ATO) light dose of light emitted by the illumination system 10 may be similar regardless whether illumination system 10 is controlled according to the temporally resolved target light setting or the redistributed temporally resolved light setting (which is determined from the redistributed temporally resolved power consumption distribution).

Figure 2 is a box scheme of a method 20 for controlling a illumination system 10 comprising one or more light sources 160, 162, 164. The method 20 may be a computer-implemented method. The method 20 comprises: obtaining S200, for a future time period, a temporally resolved overall available electric power distribution of an electrical energy grid to which the illumination system 10 is connected; obtaining S202, for the future time period, a temporally resolved target light setting comprising data pertaining to a temporally resolved intensity and correlated color temperature of light to be emitted by the one or more light sources 160, 162, 164; determining S204, from the temporally resolved target light setting, a temporally resolved electric power consumption distribution of the one or more light sources 160, 162, 164; redistributing S206 the temporally resolved electric power consumption distribution such that an overlap between a redistributed temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution is relatively larger than an overlap between the temporally resolved electric power consumption distribution and the temporally resolved overall available electric power distribution; determining S208, from the redistributed temporally resolved electric power consumption distribution, a redistributed temporally resolved light setting for the future time period; and controlling S210, during the future time period, the one or more light sources 160, 162, 164 in accordance with the adjusted temporally resolved light setting.

The method 20 may further comprise comparing S211 the temporally resolved electric power consumption distribution of the one or more light sources 160, 162, 164 and the temporally resolved overall available electric power distribution of the electrical energy grid.

The temporally resolved electric power distribution may be redistributed S206 on a condition that an accumulated intensity and correlated color temperature of light to be emitted according to the redistributed temporally resolved light setting is maintained as compared with an accumulated intensity and correlated color temperature of light to be emitted according to the temporally resolved target light setting.

The method may further comprise determining, for the future time period, an accumulated intensity and correlated color temperature of light to be emitted according to the temporally resolved target light setting.

The method 20 may further comprise normalizing the S212 temporally resolved overall available electric power distribution; and normalizing S214 the temporally resolved electric power consumption distribution.

The normalizing S212 the temporally resolved overall available electric power distribution, and the normalizing S214 the temporally resolved electric power consumption distribution may be prior to the redistributing S206 the temporally resolved electric power consumption distribution.

The redistributing S206 the temporally resolved electric power consumption distribution may comprise temporally shifting S216 the temporally resolved electric power consumption distribution.

The future time period may be a time period of 1-10 hours.

Figure 3 illustrates a non-transitory computer-readable storage medium 30. The non-transitory computer-readable storage medium 30 comprises program code portions which, when executed on a device having processing capabilities, performs the method 20 illustrated in Fig. 2.

The person skilled in the art realizes that the present inventive concept by no means is limited to the preferred variants described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

For example, the second obtaining function 1204 is described as obtaining the temporally resolved target light setting, e.g., from a server. However, it is to be understood that the second obtaining function 1204 may be configured to determine the temporally resolved target light setting, e.g., from the one or more target light profiles associated with individuals present (or planned to be present) in the space which the illumination system 10 is configured to serve.

As a further example, the first obtaining function 1202 and the second obtaining function 1204 are described as two separate functions. It is however to be understood that these functions 1202, 1204 may be implemented as a single function. Such single function may be referred to as an obtaining function.

As a further example, the first normalizing function 1214 and the second normalizing function 1216 are described as two separate functions. It is however to be understood that these functions 1214, 1216 may be implemented as a single function, and may be referred to as a normalizing function.

Additionally, variations to the disclosed variants can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.