Power receiving device, power supply device, optical power supply system, power receiving method, and optical power supply method

Abstract

To provide a power receiving device, a power feeding device, an optical power feeding system, a power receiving method, a power feeding method, and an optical power feeding method capable of simultaneously transmitting power and information via power feeding light.SOLUTION: While power transmission is performed by sending out power feeding light in which information is inserted by wavelength modulation, the power feeding light is received by a light receiving unit having different sensitivity according to a wavelength, power reception is performed by converting the power feeding light into electric power, and information is extracted based on a magnitude of the electric power that changes according to change in a wavelength of the power feeding light.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a power receiving device, a power feeding device, an optical power feeding system, a power receiving method, and an optical power feeding method.

Background Art

[0002] Recently, an optical power feeding system that converts power into light (referred to as feeding light), transmits the feeding light, and converts the feeding light into electrical energy for use as power has been studied. Patent Document 1 describes an optical transmitter that transmits signal light modulated by an electrical signal and feeding light for supplying power, an optical fiber having a core that transmits the signal light, a first cladding formed around the core and having a refractive index smaller than that of the core for transmitting the feeding light, and a second cladding formed around the first cladding and having a refractive index smaller than that of the first cladding, and an optical receiver that operates with power converted from the feeding light transmitted through the first cladding of the optical fiber and converts the signal light transmitted through the core of the optical fiber into the electrical signal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an optical power feeding system, it is useful to be able to simultaneously transmit power and information by inserting information into the feeding light.

[0005] An object of the present disclosure is to provide a power receiving device, a power feeding device, an optical power feeding system, a power receiving method, and an optical power feeding method capable of simultaneously transmitting power and information via feeding light.

Means for Solving the Problems

[0006] The power receiving device related to this disclosure is A light receiving unit that converts the incident power supply light into electricity, The system includes a demodulation unit that extracts information contained in the aforementioned power supply light, The information is inserted into the power supply light by wavelength modulation such that the wavelength of the power supply light changes to at least a first wavelength and a second wavelength. The light-receiving unit has different sensitivities at least for the first wavelength and the second wavelength. The demodulation unit extracts the information based on the magnitude of the power converted by the light receiving unit.

[0007] The power supply device related to this disclosure is A light-emitting unit that outputs power supply light and can change the wavelength of the power supply light to at least a first wavelength and a second wavelength, A modulation unit that inserts information into the power supply light by wavelength modulation that changes the wavelength of the power supply light to at least the first wavelength and the second wavelength, Equipped with, The light-emitting unit outputs the power supply light with power according to predetermined conditions, at least during the period when the modulation unit inserts information into the power supply light. And furthermore, The light-emitting unit is capable of changing the wavelength of the power-supplied light to a plurality of wavelengths including at least the maximum and minimum wavelengths in the first wavelength region, and a plurality of wavelengths including at least the maximum and minimum wavelengths in the second wavelength region. The first wavelength region and the second wavelength region are different regions that partially overlap, or different regions that do not overlap. The modulation unit is capable of wavelength modulation using the first wavelength region and wavelength modulation using the second wavelength region. Furthermore, the system includes a power transmission control unit that switches the modulation of the power supply light by the modulation unit between wavelength modulation using the first wavelength region and wavelength modulation using the second wavelength region. ru.

[0008] The optical power supply system related to this disclosure is It comprises a power supply device and a power receiving device, The power supply device is A light-emitting unit that outputs power supply light and can change the wavelength of the power supply light to at least a first wavelength and a second wavelength, A modulation unit that includes information in the power supply light by wavelength modulation that changes the wavelength of the power supply light to at least the first wavelength and the second wavelength, It has, The power receiving device is A light receiving unit that converts the incident power supply light into electricity, It has a demodulation unit that extracts information contained in the power supply light, The light receiving unit has at least different sensitivities to the first wavelength and the second wavelength, and the demodulation unit extracts the information based on the magnitude of the power converted by the light receiving unit.

[0009] The power receiving method according to the present disclosure is to convert the power supply light with information inserted by wavelength modulation into power by receiving it with a light receiving unit having a non-constant spectral sensitivity, and further extract the information based on the magnitude of the power that changes corresponding to the change in the wavelength of the power supply light.

[0011] The optical power supply method according to the present disclosure is while transmitting power by sending out power supply light with information inserted by wavelength modulation, receiving the power supply light with a light receiving unit having a non-constant spectral sensitivity, performing power reception by converting the power supply light into power, and further extracting the information based on the magnitude of the power that changes corresponding to the change in the wavelength of the power supply light.

Advantages of the Invention

[0012] According to the present disclosure, an effect that power and information can be simultaneously transmitted via the power supply light can be obtained.

Brief Description of the Drawings

[0013] [Figure 1] It is a configuration diagram of an optical power supply system according to the first embodiment of the present disclosure. [Figure 2] It is a configuration diagram of an optical power supply system according to the second embodiment of the present disclosure. [Figure 3] It is a configuration diagram of an optical power supply system according to the second embodiment of the present disclosure, showing an optical connector and the like. [Figure 4] It is a configuration diagram of an optical power supply system according to another embodiment of the present disclosure. 4 [Figure 5] It is a configuration diagram of an optical power supply system according to another embodiment of the present disclosure. [Figure 6] It is a configuration diagram of an optical power supply system according to another embodiment of the present disclosure. [Figure 7] This is a configuration diagram showing an optical power supply system according to a third embodiment, in which a configuration is applied to transmit power and information via power supply light. [Figure 8] This graph shows an example of the spectral sensitivity characteristics of a photoelectric conversion element. [Figure 9] This is a configuration diagram showing an optical power supply system according to a fourth embodiment, in which a configuration is applied to transmit power and information via power supply light. [Figure 10] This flowchart shows an example of a transmission process performed in the fourth embodiment. [Modes for carrying out the invention]

[0014] An embodiment of this disclosure will be described below with reference to the drawings.

[0015] (1) System Overview [First Embodiment] As shown in Figure 1, the optical power supply system 1A of this embodiment comprises a power supply device (PSE) 110, an optical fiber cable 200A, and a powered device (PD) 310. Since the optical power supply system 1A transmits power supply light via the optical fiber 250A, it may also be called an optical fiber power supply (PoF) system. In this disclosure, the power supply device is a device that converts electrical power into light energy and supplies it, and the power receiving device is a device that receives light energy and converts said light energy into electrical power. The power supply device 110 includes a power supply semiconductor laser 111. The fiber optic cable 200A includes a fiber optic cable 250A that forms the transmission path for the power supply light. The power receiving device 310 includes a photoelectric conversion element 311.

[0016] The power supply device 110 is connected to a power source, and the power supply semiconductor laser 111 and other components are electrically driven. The power supply semiconductor laser 111 oscillates using the power from the above-mentioned power supply and outputs power supply light 112.

[0017] The optical fiber cable 200A has one end 201A that can be connected to the power supply device 110 and the other end 202A that can be connected to the power receiving device 310, and transmits power supply light 112. The power supply light 112 from the power supply device 110 is input to one end 201A of the optical fiber cable 200A, the power supply light 112 propagates through the optical fiber 250A, and is output to the power receiving device 310 from the other end 202A.

[0018] The photoelectric conversion element 311 converts the power supply light 112 transmitted through the optical fiber cable 200A into electrical power. The electrical power converted by the photoelectric conversion element 311 is used as the required driving power within the power receiving device 310. Furthermore, the power receiving device 310 is capable of outputting the electrical power converted by the photoelectric conversion element 311 for use with external devices.

[0019] The semiconductor material constituting the semiconductor region that performs the photoelectric-electrical conversion effect of the power supply semiconductor laser 111 and the photoelectric conversion element 311 is a semiconductor with a short laser wavelength of 500 nm or less. Semiconductors with short-wavelength lasers have a large band gap and high photoelectric conversion efficiency, which improves the photoelectric conversion efficiency on both the power generation and receiving sides of optical power supply, thereby improving the overall optical power supply efficiency. To achieve this, semiconductor materials such as diamond, gallium oxide, aluminum nitride, and GaN, which are laser mediums with a laser wavelength (fundamental wave) of 200 to 500 nm, may be used as the semiconductor material. Furthermore, the semiconductor material used will be a semiconductor with a band gap of 2.4 eV or greater. For example, semiconductor materials with a band gap of 2.4 to 6.2 eV, such as diamond, gallium oxide, aluminum nitride, and GaN, may be used as the laser medium. Furthermore, laser light tends to have better transmission efficiency at longer wavelengths and better photoelectric conversion efficiency at shorter wavelengths. Therefore, for long-distance transmission, semiconductor materials with a laser wavelength (fundamental wave) greater than 500 nm may be used as the laser medium. Alternatively, if photoelectric conversion efficiency is prioritized, semiconductor materials with a laser wavelength (fundamental wave) less than 200 nm may be used as the laser medium. These semiconductor materials may be applied to either the power supply semiconductor laser 111 or the photoelectric conversion element 311. This improves the photoelectric conversion efficiency on either the power supply or power receiving side, thereby improving the optical power supply efficiency.

[0020] [Second Embodiment] As shown in Figure 2, the optical power supply system 1 of this embodiment includes a power over fiber (PoF) system and an optical communication system, and comprises a first data communication device 100 including a power supply equipment (PSE) 110, an optical fiber cable 200, and a second data communication device 300 including a powered device (PD) 310. The power supply device 110 includes a power supply semiconductor laser 111. The first data communication device 100 includes the power supply device 110, as well as a data communication transmitting unit 120 and a receiving unit 130. The first data communication device 100 corresponds to a data terminal equipment (DTE), repeater, etc. The transmitting unit 120 includes a signal semiconductor laser 121 and a modulator 122. The receiving unit 130 includes a signal photodiode 131.

[0021] The optical fiber cable 200 includes an optical fiber 250 having a core 210 that forms a transmission path for signal light and a cladding 220 that is arranged on the outer periphery of the core 210 and forms a transmission path for power supply light.

[0022] The power receiving device 310 includes a photoelectric conversion element 311. The second data communication device 300 includes the power receiving device 310, a transmitting unit 320, a receiving unit 330, and a data processing unit 340. The second data communication device 300 is a Power End Station. This corresponds to the above. The transmitting unit 320 includes a signal semiconductor laser 321 and a modulator 322. The receiving unit 330 includes a signal photodiode 331. The data processing unit 340 is a unit that processes the received signals. The second data communication device 300 is a node in the power supply network. Alternatively, the second data communication device 300 may be a node that communicates with other nodes.

[0023] The first data communication device 100 is connected to a power supply, and the power supply semiconductor laser 111, the signal semiconductor laser 121, the modulator 122, the signal photodiode 131, etc. are electrically driven. The first data communication device 100 is a node in the power supply network. Alternatively, the first data communication device 100 may be a node that communicates with other nodes. The power supply semiconductor laser 111 oscillates using the power from the above-mentioned power supply and outputs power supply light 112.

[0024] The photoelectric conversion element 311 converts the power supply light 112 transmitted through the optical fiber cable 200 into electrical power. The electrical power converted by the photoelectric conversion element 311 is used as the driving power for the transmitting unit 320, the receiving unit 330, and the data processing unit 340, as well as other driving power required within the second data communication device 300. Furthermore, the second data communication device 300 may be capable of outputting the electrical power converted by the photoelectric conversion element 311 for use with external devices.

[0025] Meanwhile, the modulator 122 of the transmitter 120 modulates the laser light 123 from the signal semiconductor laser 121 based on the transmission data 124 and outputs it as signal light 125. The signal photodiode 331 of the receiving unit 330 demodulates the signal light 125 transmitted through the optical fiber cable 200 into an electrical signal and outputs it to the data processing unit 340. The data processing unit 340 transmits the data in the form of the electrical signal to a node, and at the same time receives data from that node and outputs it to the modulator 322 as transmitted data 324. The modulator 322 of the transmitter 320 modulates the laser light 323 from the signal semiconductor laser 321 based on the transmission data 324 and outputs it as signal light 325. The signal photodiode 131 of the receiving unit 130 demodulates the signal light 325 transmitted through the optical fiber cable 200 into an electrical signal and outputs it. Data obtained from this electrical signal This is sent to the node, and in turn, data is sent from that node and designated as data 124.

[0026] Power supply light 112 and signal light 125 from the first data communication device 100 are input to one end 201 of the optical fiber cable 200. The power supply light 112 propagates through the cladding 220, and the signal light 125 propagates through the core 210. The other end 202 is then output to the second data communication device 300. The signal light 325 from the second data communication device 300 is input to the other end 202 of the optical fiber cable 200, propagates through the core 210, and is output from one end 201 to the first data communication device 100.

[0027] As shown in Figure 3, the first data communication device 100 is provided with an optical input / output unit 140 and an optical connector 141 attached thereto. The second data communication device 300 is provided with an optical input / output unit 350 and an optical connector 351 attached thereto. An optical connector 230 provided at one end 201 of the optical fiber cable 200 is connected to the optical connector 141. An optical connector 240 provided at the other end 202 of the optical fiber cable 200 is connected to the optical connector 351. The optical input / output unit 140 guides the power supply light 112 to the cladding 220, the signal light 125 to the core 210, and the signal light 325 to the receiving unit 130. The optical input / output unit 350 guides the power supply light 112 to the power receiving device 310, the signal light 125 to the receiving unit 330, and the signal light 325 to the core 210. As described above, the optical fiber cable 200 has one end 201 that can be connected to the first data communication device 100 and the other end 202 that can be connected to the second data communication device 300, and transmits power supply light 112. Furthermore, in this embodiment, the optical fiber cable 200 transmits signal light 125,325 bidirectionally.

[0028] The semiconductor material used to constitute the semiconductor region that performs the optical-electrical conversion effect of the power supply semiconductor laser 111 and the photoelectric conversion element 311 is the same as that used in the first embodiment, thereby achieving high optical power supply efficiency.

[0029] Furthermore, as shown in Figure 4, the optical fiber cable 200B of the optical power supply system 1B may be provided separately for the optical fiber 260 that transmits signal light and the optical fiber 270 that transmits power supply light. The optical fiber cable 200B may also be composed of multiple cables.

[0030] Furthermore, as shown in Figure 5, the optical power supply system 1C may transmit the power supply light 112 through space. This type of optical power supply is called PoA (Power over Air).

[0031] In the PoA (Power over Air) optical power supply system 1C, the power supply device 110 may have a collimator lens 115 and send the power supply light 112 emitted from the power supply semiconductor laser 111 into space via the collimator lens 115. However, the collimator lens 115 may be omitted if the spread of the power supply light 112 is small. The power receiving device 310 may have a lens 313 such as a focusing lens or a diffusing lens, and the power supply light 112 may be incident on the photoelectric conversion element 311 via the lens 313. Alternatively, the power receiving device 310 may not have a lens 313, and the power supply light 112 may be incident directly on the photoelectric conversion element 311.

[0032] Furthermore, as shown in Figure 6, the optical power supply system 1D may transmit the power supply light 112 via optical fiber 270D in one section 501 and via space in another section 502. A collimator lens 281 may or may not be located at the beginning of section 502. A lens 282, such as a focusing lens or a diffusing lens, may or may not be located at the end of section 502.

[0033] (2) Application of a configuration that transmits power and information via the power supply light 112 Next, we will describe an optical power supply system in which a configuration is applied to transmit power and information via the power supply optical fiber 112.

[0034] [Third Embodiment] Figure 7 is a configuration diagram showing an optical power supply system 1E according to the third embodiment, in which a configuration is applied to transmit power and information via the power supply light 112. Figure 8 is a graph showing the spectral sensitivity of the photoelectric conversion element.

[0035] The optical power supply system 1E of the third embodiment comprises a power supply device 110E and a power receiving device 310E.

[0036] The power supply device 110E includes a light-emitting unit 111E that outputs power supply light 112 and a modulation unit 150 that inserts information into the power supply light 112.

[0037] The light-emitting unit 111E has the function of changing the wavelength of the power-fed light 112 to at least a first wavelength λ1 and a second wavelength λ2. The light-emitting unit 111E may be configured to discretely change the wavelength of the power-fed light 112 from the first wavelength λ1 to the nth wavelength λn (where n is an integer of 2 or more), or it may be configured to continuously change the wavelength from the first wavelength λ1 to the nth wavelength λn. The light-emitting unit 111E may be a single power-fed semiconductor laser having a wavelength-tunable structure, or it may include a plurality of power-fed semiconductor lasers with different oscillation wavelengths, and the power-fed semiconductor laser emitting the power-fed light 112 may be switchable.

[0038] The light-emitting unit 111E outputs the power supply light 112 at a power level according to predetermined conditions, at least during the period in which information is inserted into the power supply light 112. The power supply device 110E includes a power control unit that controls the power of the light-emitting unit 111E, and the light-emitting unit 111E may emit the power supply light 112 at the above power level under the control of the power control unit. "Power level according to predetermined conditions" refers to, for example, a constant power level.

[0039] Furthermore, "power according to predetermined conditions" is not limited to a constant power. For example, "power according to predetermined conditions" may be power that changes according to various conditions, such as power that changes depending on the time, or power that changes according to the request of the power receiving device 310E. In other words, the power of the power supply light 112 output by the light-emitting unit 111E only needs to have predetermined conditions for determining the power, so that the power supply light 112 can be known in advance by the power receiving device 310E.

[0040] The modulation unit 150 inserts information into the feed light 112 by performing wavelength modulation, which changes the wavelength of the feed light 112 output from the light-emitting unit 111E to at least a first wavelength λ1 and a second wavelength λ2. The wavelength modulation may be a modulation that discretely changes the wavelength of the feed light 112 from the first wavelength λ1 to the nth wavelength λn (where n is an integer of 2 or more), or it may be a modulation that continuously changes the wavelength of the feed light 112 in a region including the first wavelength λ1 to the nth wavelength λn. The wavelength modulation method may be digital modulation or analog modulation. The modulation unit 150 may also insert information into the feed light 112 by a modulation method that combines the change in wavelength with changes in elements other than wavelength and power.

[0041] The power receiving device 310E comprises a light receiving unit 311E and a demodulation unit 370.

[0042] The light receiving unit 311E converts the power supply light 112 into electrical power. The electrical power converted by the light receiving unit 311E is supplied to the subsequent load (electrical circuit, electrical device, etc.), and the load operates using this electrical power.

[0043] The light-receiving unit 311E is a photoelectric conversion element in which the sensitivity at least at the first wavelength λ1 and the sensitivity at the second wavelength λ2 are different. Specifically, as shown in Figure 8, the light-receiving unit 311E may be a photoelectric conversion element having characteristics in which the sensitivity at all wavelengths from the first wavelength λ1 to the nth wavelength λn is different, or it may be a photoelectric conversion element having characteristics in which the sensitivity changes continuously with a gradient in the same direction from the first wavelength λ1 to the nth wavelength λn.

[0044] Here, sensitivity refers to the magnitude of power converted when a single-wavelength, unit-power fed light 112 is incident on it. In the spectral sensitivity characteristic graph in Figure 8, the relative spectral response on the vertical axis represents the relative value of the short-circuit current output from the photoelectric conversion element when a single-wavelength light is incident on it. When a different wavelength and the same power of fed light 112 is incident on the light receiving unit 311E, the magnitude of the power output from the light receiving unit 311E is converted as shown in the characteristics of Figure 8.

[0045] The light-receiving unit 311E may be the photoelectric conversion element 311 shown in Embodiment 1. Alternatively, the light-receiving unit 311E may be a solar cell. The sensitivity of the solar cell may vary depending on its material, composition, or crystal structure. The type of solar cell to be used should be selected by considering various technical factors such as its application and the characteristics of the semiconductor laser used for power supply, but for example, the following solar cells can be given as examples. That is, the solar cell may include, but is not limited to, silicon-based solar cells such as monocrystalline silicon, polycrystalline silicon, or heterojunction type, or compound-based solar cells (for example, GaN-based, GaAs-based, InGaP-based, InGaAs-based, or Ge-based solar cells, or tandem-type solar cells formed by joining at least two or more of these types of solar cells). By using such a solar cell, a large light-receiving surface can be realized at low cost. With a large light-receiving surface, even if the power-supplying light 112 spreads out relatively widely by transmitting the power-supplying light 112 through space, efficient light reception becomes possible. Furthermore, by employing the above-mentioned solar cell, it is easier to obtain spectral sensitivity characteristics in which the sensitivity changes continuously with a gradient in the same direction in the wavelength range suitable for the power supply light 112.

[0046] According to the light-receiving unit 311E having the above characteristics, for example, the magnitude of power converted when a first wavelength λ1 feeding light 112 is incident at a first power, the magnitude of power converted when a second wavelength λ2 feeding light 112 is incident at the same first power, ..., the magnitude of power converted when an nth wavelength λn feeding light 112 is incident at the same first power are all different from each other. That is, when the power of the feeding light 112 incident on the light-receiving unit 311E is constant, the difference in the wavelength of the feeding light 112 appears as a difference in the magnitude of power converted by the light-receiving unit 311E.

[0047] The demodulation unit 370 detects the magnitude of the power converted by the light receiving unit 311E and extracts the information inserted into the power supply light 112 based on the detected magnitude of the power. That is, the wavelength of the power supply light 112 into which information has been inserted by wavelength modulation changes due to the inserted information. This change in wavelength is converted into a change in the magnitude of power by the light receiving unit 311E. Therefore, the demodulation unit 370 can extract the information by treating the information inserted by wavelength modulation as information inserted by power magnitude modulation and performing demodulation processing based on the magnitude of power.

[0048] Furthermore, the demodulation unit 370 may have data showing the relationship between the sensitivity of the light receiving unit 311E and the wavelength, and may perform processing to estimate the wavelength of the power supply light 112 from this data and the magnitude of the detected power, and to extract information based on the estimated wavelength.

[0049] The detection of the power magnitude by the demodulation unit 370 can be achieved by various methods, such as detecting the current value supplied from the light receiving unit 311E to the load (when the voltage is constant), detecting the voltage value supplied from the light receiving unit 311E to the load (when the current is constant), or detecting both the current value and the voltage value.

[0050] Furthermore, although the above description described the case where the power of the power supply light 112 is constant, the power of the power supply light 112 is not constant and may change according to predetermined conditions. Even when the power changes, the demodulation unit 370 can obtain the power value of the power supply light 112 according to predetermined conditions. Once the power value is obtained, the relationship between the magnitude of the converted power and the wavelength when the power supply light 112 of that power is incident can be calculated. Then, the wavelength can be calculated based on this relationship and the magnitude of the power output from the light receiving unit 311E. Therefore, even in this case, the demodulation unit 370 can extract the information inserted by wavelength modulation based on the magnitude of the power converted by the light receiving unit 311E.

[0051] As described above, according to the optical power supply system 1E of the third embodiment, information and power can be transmitted simultaneously using the power supply light 112 as a medium.

[0052] Furthermore, since the power supply device 110E inserts information into the power supply light 112 by wavelength modulation, it can reduce fluctuations in the power of the power supply light 112 due to the information compared to cases where information is inserted into the power supply light 112 by pulse modulation or power modulation. Therefore, the power supply device 110E can provide a stable power supply while transmitting information. Moreover, by employing a power supply semiconductor laser with a wavelength tunable structure as the light-emitting unit 111E, the power supply device 110E can be configured simply.

[0053] Furthermore, the power receiving device 310E has a light-receiving section 311E with different sensitivities depending on the wavelength of the incident light, and the demodulation section 370 extracts information based on the magnitude of the power converted by the light-receiving section 311E. Therefore, the power receiving device 310E can be simply configured without requiring a light-receiving section dedicated to information reception. Moreover, the power receiving device 310E can be simply configured without requiring a configuration that spectrally analyzes according to wavelength.

[0054] The power supply device 110E and power receiving device 310E of the third embodiment may be applied to the optical power supply system 1A of Figure 1, which transmits power supply light 112 via optical fiber cable 200A, or to the optical power supply systems 1, 1B to 1D of Figures 2 to 6, which have a separate data transmission function. That is, the power supply device 110 in Figures 1 to 6 may be replaced with the power supply device 110E, and the power receiving device 310 in Figures 1 to 6 may be replaced with the power receiving device 310E. When applied to the optical power supply systems 1, 1B to 1D of Figures 2 to 6, two systems of data transmission become possible: data transmission via signal light 125 and 325, and information transmission via power supply light 112.

[0055] [Fourth Embodiment] Figure 9 is a configuration diagram showing an optical power supply system 1F according to the fourth embodiment, in which a configuration is applied to transmit power and information via the power supply light 112. In Figure 9, the same reference numerals are used for components that are the same as those in the third embodiment, and detailed descriptions are omitted.

[0056] The optical power supply system 1F according to the fourth embodiment comprises a power supply device 110F and a power receiving device 310F.

[0057] The power supply device 110F includes a light-emitting unit 111E that outputs power supply light 112, a modulation unit 150 that inserts information into the power supply light 112, a power transmission control unit 160 that controls the transmission of power supply light 112 and information transmission, and a receiving unit 170 that receives data 392 from the power receiving device 310F.

[0058] The power receiving device 310F includes a light receiving unit 311E that converts the power supply light 112 into electricity, a demodulation unit 370 that extracts information contained in the power supply light 112, a power receiving control unit 380 that performs control related to information transmission via the power supply light 112, and a transmission unit 390 that transmits data 392 to the power supply device 110F.

[0059] The transmitting unit 390 and the receiving unit 170 may be configured to transmit and receive data 392 using any medium, such as signal light, power supply light 112 or reflected signal light, radio waves, or wired electrical signals.

[0060] The power transmission control unit 160 performs control to switch the wavelength range of the power supply light 112 used by the modulation unit 150, and control to perform calibration processing by driving the light emission unit 111E.

[0061] The power receiving control unit 380 performs calibration processing and information transmission response processing.

[0062] <Wavelength region switching process> As described in the third embodiment, the modulation unit 150 and the demodulation unit 370 can transmit information via the power supply light 112 by wavelength modulation and demodulation of the power supply light 112. Wavelength modulation can be performed using the first wavelength region 401 in Figure 8, or using the second wavelength region 402, and several options are available.

[0063] Therefore, the power transmission control unit 160 switches the wavelength range used for wavelength modulation between at least the first wavelength range 401 and the second wavelength range 402, depending on the situation. The wavelength range used for wavelength modulation refers to the range between the maximum value (maximum wavelength) and the minimum value (minimum wavelength) of the wavelength that is changed by wavelength modulation.

[0064] The first wavelength region 401 is a region in which the light receiving unit 311E can efficiently convert light into power, but its width is narrow. Therefore, if the first wavelength region 401 is selected, the efficiency of power transmission can be improved, but the amount of information that can be transmitted per unit time will be relatively small. The second wavelength region 402 has a wide width, but it includes wavelength regions in which the power conversion efficiency of the light receiving unit 311E is relatively low. Therefore, if the second wavelength region 402 is selected, the amount of information that can be transmitted per unit time will be large, but the efficiency of power transmission will be relatively reduced.

[0065] Therefore, the power transmission control unit 160 may select the first wavelength range 401 when the power to be transmitted is large, and select the second wavelength range 402 when the power to be transmitted is small and the amount of information to be transmitted is large. By selecting the appropriate wavelength range according to the situation, the power transmission control unit 160 can achieve power and information transmission that is suitable for the situation.

[0066] Furthermore, the wavelength ranges that the power transmission control unit 160 switches depending on the situation may be three or more wavelength ranges, and the multiple wavelength ranges may partially overlap or not overlap at all. The above "situation" may include various situations such as the amount of surplus power in the power receiving device 310F and changes in the characteristics of the space through which the power supply light 112 is transmitted (e.g., humidity).

[0067] <Calibration process> In the power supply device 110F, when the power of the power supply light 112 is switched from the first power to the second power, or when the wavelength range used for wavelength modulation is switched, it takes time for the power receiving device 310F to detect the switch. During this time, information transmission becomes difficult. To shorten the time during which information transmission is difficult, the power transmission control unit 160 and the power receiving control unit 380 may perform the following calibration process.

[0068] During the calibration process, the following two elements are determined:

[0069] The first element is a reference value for the power converted from the power supply light 112 by the power receiving device 310F. This reference value represents the magnitude of the power converted by the light receiving unit 311E when power supply light 112 of a predetermined wavelength is incident on it. The predetermined wavelength can be, for example, the longest wavelength in the wavelength range used for wavelength modulation, the central wavelength in that wavelength range, the shortest wavelength, or the i-th wavelength.

[0070] Since the above reference value is known, the demodulation unit 370 can identify how far the wavelength of the incoming power supply light 112 is from the wavelength of the reference value by comparing the magnitude of the power converted by the light receiving unit 311E with the reference value. Therefore, even after the power of the power supply light 112 is switched, the demodulation unit 370 can quickly proceed to demodulation processing by performing calibration processing.

[0071] The second element is a value that can distinguish the maximum and minimum wavelengths in the wavelength range used for wavelength modulation. Specifically, it is the magnitude of the power converted by the light receiving unit 311E when the maximum wavelength feed light 112 is incident (first reference value of power), and the magnitude of the power converted by the light receiving unit 311E when the minimum wavelength feed light 112 is incident (second reference value of power).

[0072] The demodulation unit 370 can calculate the wavelength range used for wavelength modulation once the first and second reference values ​​are known. Therefore, the demodulation unit 370 can quickly proceed to demodulation processing even after the wavelength range has been switched.

[0073] <Transmission and processing of power and information via power supply light 112> Figure 10 is a flowchart showing an example of a transmission process performed in the fourth embodiment. In this transmission process, the condition is applied that the power of the power supply light 112 is constant during the period in which information is inserted into the power supply light 112.

[0074] When the transmission process begins, the power transmission control unit 160 first selects either a first wavelength region 401 that can transmit power efficiently, or a second wavelength region 402 that can easily transmit a large amount of information, as the wavelength region to be used for wavelength modulation (step S1). Here, the power transmission control unit 160 may select the wavelength region according to the amount of information to be transmitted and the amount of power to be sent to the power receiving device 310F.

[0075] Next, the power transmission control unit 160 and the power reception control unit 380 perform a calibration process (step S2). Specifically, the power transmission control unit 160 controls the light emission unit 111E to switch the wavelength of the power supply light 112 between the maximum wavelength and the minimum wavelength of the wavelength range selected in step S1 in a predetermined pattern. When the magnitude of the power converted by the light receiving unit 311E changes in the predetermined pattern, the power reception control unit 380 recognizes that a calibration process is being performed and sets the larger power as the first reference value and the smaller power as the second reference value.

[0076] Once the first and second reference values ​​are set, the power receiving control unit 380 sends an acknowledgment (ACK) to the receiving unit 170 via the transmitting unit 390. When the power transmission control unit 160 receives the acknowledgment (YES in step S3), the calibration process is completed.

[0077] Next, the power transmission control unit 160 instructs the modulation unit 150 to start modulation processing, and the power reception control unit 380 instructs the demodulation unit 370 to start demodulation processing, thereby performing the transmission of power and information via the power supply light 112 (step S4).

[0078] Then, once the transmission of information from the power supply device 110F is complete and the power receiving control unit 380 sends an acknowledgment (ACK) to the receiving unit 170 via the transmitting unit 390 (YES in step S5), the process of simultaneously transmitting both power and information is completed (step S6).

[0079] Subsequently, the power transmission control unit 160 controls the light-emitting unit 111E to set the wavelength of the power supply light 112 to a wavelength that is highly sensitive to the light-receiving unit 311E (a wavelength with high power conversion efficiency) (step S7). Then, the power transmission control unit 160 continues the power transmission process using the power supply light 112 (step S8).

[0080] While power is being transmitted via the power supply light 112, the power transmission control unit 160 determines whether an information transmission request has occurred (step S9). If the result is NO, it continues the transmission process in step S8; if the result is YES, it returns to step S4 and resumes the information transmission process. Alternatively, if the determination result in step S9 is YES, the power transmission control unit 160 may return to the process in step S1 and resume the process for transmitting information, starting with the selection of the wavelength range.

[0081] As described above, according to the optical power supply system 1F of Embodiment 4, the demodulation unit 370 of the power receiving device 310F extracts information inserted into the power supply light 112 based on the magnitude of the power converted by the light receiving unit 311E and a reference value of said power. Then, the power receiving control unit 380 of the power receiving device 310F performs a calibration process to determine the above reference value. Thus, after at least one of the power and wavelength range of the power supply light 112 is changed, the power receiving control unit 380 can quickly determine the above reference value through the calibration process and quickly start the demodulation process by the demodulation unit 370.

[0082] The calibration process is not limited to the above example. For example, if the power receiving device 310F requests power from the power supply device 110F for the power of the power supply light 112, and the power supply device 110F controls the power of the power supply light 112 in response to the request, the power receiving control unit 380 may determine a reference value for the power based on the above request. Alternatively, the power receiving device 310F may have a measuring instrument for measuring the power of the incident power supply light 112, and may perform a calibration process to determine the reference value for the power by temporarily measuring the power with the measuring instrument.

[0083] According to the optical power supply system 1F of Embodiment 4, the power supply device 110F includes a power transmission control unit 160 that switches the wavelength range used for wavelength modulation of the power supply light 112. Therefore, the power supply device 110F can transmit power and information by the power supply light 112 using a wavelength range suitable for various situations, such as when the transmission of a lot of information is required by the power supply light 112, or when the power to be transmitted is large or small.

[0084] The embodiments of this disclosure have been described above. However, the power receiving device, power supply device, optical power supply system, power receiving method, power supply method, and optical power supply method of this disclosure are not limited to the embodiments described above. Details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention.

[0085] The following describes one embodiment of this disclosure. In one embodiment, (1) The power receiving device is A light receiving unit that converts the incident power supply light into electricity, The system includes a demodulation unit that extracts information contained in the aforementioned power supply light, The information is inserted into the power supply light by wavelength modulation such that the wavelength of the power supply light changes to at least a first wavelength and a second wavelength. The light-receiving unit has different sensitivities at least for the first wavelength and the second wavelength. The demodulation unit extracts the information based on the magnitude of the power converted by the light receiving unit.

[0086] (2) In the power receiving device described in (1) above, The demodulation unit extracts the information based on the reference value of the power magnitude and the power magnitude converted by the light receiving unit. The system further includes a power receiving control unit that performs calibration processing to determine the aforementioned reference value.

[0087] (3) In the power receiving device described in (1) or (2) above, The light-receiving part is a solar cell.

[0088] (4) In the power receiving device described in (1) or (2) above, The light-receiving unit is a photoelectric conversion element.

[0089] (5) The power supply device is A light-emitting unit that outputs power supply light and can change the wavelength of the power supply light to at least a first wavelength and a second wavelength, A modulation unit that inserts information into the power supply light by wavelength modulation that changes the wavelength of the power supply light to at least the first wavelength and the second wavelength, Equipped with, The light-emitting unit outputs the power supply light with a power according to predetermined conditions, at least during the period in which the modulation unit inserts information into the power supply light.

[0090] (6) In the power supply device described in (5) above, The light-emitting unit is capable of changing the wavelength of the power-supplied light to a plurality of wavelengths including at least the maximum and minimum wavelengths in the first wavelength region, and a plurality of wavelengths including at least the maximum and minimum wavelengths in the second wavelength region. The first wavelength region and the second wavelength region are different regions that partially overlap, or different regions that do not overlap. The modulation unit is capable of wavelength modulation using the first wavelength region and wavelength modulation using the second wavelength region. Furthermore, the system includes a power transmission control unit that switches the modulation of the power supply light by the modulation unit between wavelength modulation using the first wavelength region and wavelength modulation using the second wavelength region.

[0091] (7) The optical power supply system is It comprises a power supply device and a power receiving device, The power supply device is A light-emitting unit that outputs power supply light and can change the wavelength of the power supply light to at least a first wavelength and a second wavelength, A modulation unit that includes information in the power supply light by wavelength modulation that changes the wavelength of the power supply light to at least the first wavelength and the second wavelength, It has, The power receiving device is A light receiving unit that converts the incident power supply light into electricity, It has a demodulation unit that extracts information contained in the power supply light, The light-receiving unit has different sensitivities at least for the first wavelength and the second wavelength. The demodulation unit extracts the information based on the magnitude of the power converted by the light receiving unit.

[0092] (8) Method of receiving power: The power supply light, into which information has been inserted by wavelength modulation, is received by a light receiving unit with different sensitivities depending on the wavelength, thereby converting the power supply light into electricity. Furthermore, the information is extracted based on the magnitude of the electricity, which changes in response to changes in the wavelength of the power supply light.

[0093] (9) Power supply method: Information is inserted into a power supply light with predetermined power conditions by wavelength modulation, and the power supply light with the inserted information is transmitted.

[0094] (10) The method of optical power supply is: Power transmission is performed by sending out power-supplying light into which information has been inserted through wavelength modulation, The light receiving unit, which has different sensitivities depending on the wavelength, receives the power supply light, converts the power supply light into electricity to perform power reception, and further extracts the information based on the magnitude of the electricity, which changes in response to changes in the wavelength of the power supply light. [Explanation of symbols]

[0095] 1. 1A~1F Optical Power Supply System 110, 110E, 110F Power Supply Unit 111 Semiconductor laser for power supply 111E Light-emitting section 112 Power supply light 150 Modulation section 160 Power transmission control unit 170 Receiver 200 fiber optic cables 200A Fiber Optic Cable 200B Fiber Optic Cable 310, 310E, 310F Power receiving equipment 311 Photoelectric conversion element 311E Light receiving part 370 Demodulation Unit 380 Power Receiving Control Unit 390 Transmitter 392 data λ1~λn 1st wavelength~nth wavelength 401 1st wavelength region 402 Second wavelength region

Claims

1. A light receiving unit that converts the incident power supply light into electricity, The system includes a demodulation unit that extracts information contained in the aforementioned power supply light, The information is inserted into the power supply light by wavelength modulation such that the wavelength of the power supply light changes to at least a first wavelength and a second wavelength. The light-receiving unit has different sensitivities at least for the first wavelength and the second wavelength. The demodulation unit is a power receiving device that extracts the information based on the magnitude of the power converted by the light receiving unit.

2. The demodulation unit extracts the information based on the reference value of the power magnitude and the power magnitude converted by the light receiving unit. The power receiving device according to claim 1, further comprising a power receiving control unit that performs calibration processing to determine the aforementioned reference value.

3. The light-receiving part is a solar cell. The power receiving device according to claim 1.

4. The light-receiving unit is a photoelectric conversion element. The power receiving device according to claim 1.

5. A light-emitting unit that outputs power supply light and can change the wavelength of the power supply light to at least a first wavelength and a second wavelength, A modulation unit that inserts information into the power supply light by wavelength modulation that changes the wavelength of the power supply light to at least the first wavelength and the second wavelength, Equipped with, The light-emitting unit outputs the power supply light with power according to predetermined conditions, at least during the period when the modulation unit inserts information into the power supply light, and further, The light-emitting unit is capable of changing the wavelength of the power-supplied light to a plurality of wavelengths including at least the maximum and minimum wavelengths in a first wavelength region, and a plurality of wavelengths including at least the maximum and minimum wavelengths in a second wavelength region. The first wavelength region and the second wavelength region are different regions that partially overlap, or different regions that do not overlap. The modulation unit is capable of wavelength modulation using the first wavelength region and wavelength modulation using the second wavelength region. Furthermore, the power supply device includes a power transmission control unit that switches the modulation of the power supply light by the modulation unit between wavelength modulation using the first wavelength region and wavelength modulation using the second wavelength region.

6. It comprises a power supply device and a power receiving device, The power supply device is A light-emitting unit that outputs power supply light and can change the wavelength of the power supply light to at least a first wavelength and a second wavelength, A modulation unit that includes information in the power supply light by wavelength modulation that changes the wavelength of the power supply light to at least the first wavelength and the second wavelength, It has, The power receiving device is A light receiving unit that converts the incident power supply light into electricity, It has a demodulation unit that extracts information contained in the power supply light, The light-receiving unit has different sensitivities at least for the first wavelength and the second wavelength. The demodulation unit extracts the information based on the magnitude of the power converted by the light receiving unit. Optical power supply system.

7. A power receiving method that converts power-supplying light, into which information has been inserted by wavelength modulation, into power-supplying light by receiving the light with different sensitivities depending on the wavelength, and further extracts the information based on the magnitude of the power which changes in response to changes in the wavelength of the supplying light.

8. Power transmission is performed by sending out power-supplying light into which information has been inserted through wavelength modulation, A light-based power supply method that receives the power supply light with a light-receiving unit having different sensitivities depending on the wavelength, converts the power supply light into electricity to perform power reception, and further extracts the information based on the magnitude of the electricity which changes in response to changes in the wavelength of the power supply light.

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