Power generation device and electrical apparatus

Abstract

A power generation device according to one embodiment of the present technology is provided with a transmission unit and a rectification circuit. The transmission unit is provided in an electrical apparatus, is connected directly or by capacitive coupling to at least one heat dissipation plate having a potential different from that of GND of the electrical apparatus, and transmits AC power of electromagnetic noise generated in the at least one heat dissipation plate. The rectification circuit rectifies the AC power transmitted by the transmission unit and outputs DC power.

Description

Power generation equipment and electrical equipment

[0001] The present technology relates to a power generation device and an electrical device that can be applied to energy harvesting and the like.

[0002] In recent years, energy harvesting devices that harvest power from the environment have been developed. For example, Patent Document 1 describes an antenna device that harvests power from metal parts of industrial products. In this antenna device, metal parts attached to industrial products such as various electrical devices and metal racks are used as antennas, and electric field energy induced in the metal parts is harvested as power. This method makes it possible to harvest electric field energy that includes low-frequency components called quasi-electrostatic fields and high-frequency components such as electromagnetic waves propagating through space (see, for example, paragraphs

[0011] ,

[0014] ,

[0032] , and

[0033] , and Figures 1 and 13 of the specification of Patent Document 1).

[0003] International Publication No. 2021 / 261076

[0004] Electrical devices operate using power supplied from a power source and generate electric field energy such as electromagnetic noise, so they are expected to be a power source for highly efficient energy harvesting. Therefore, there is a demand for technology that can efficiently harvest power from electrical devices.

[0005] In view of the above circumstances, an object of the present technology is to provide a power generation device and an electric device that can efficiently harvest power from the electric device.

[0006] To achieve the above object, a power generation device according to an embodiment of the present technology includes a transmission unit and a rectifier circuit. The transmission unit is connected directly or by capacitive coupling to at least one heat sink provided in an electrical device and having a potential different from a GND of the electrical device, and transmits AC power of electromagnetic noise generated on the at least one heat sink. The rectifier circuit rectifies the AC power transmitted by the transmission unit and outputs DC power.

[0007] In this power generation device, AC power generated by electromagnetic noise generated on the heat sink, which has a different potential from the GND of the electrical equipment, is transmitted by the transmission unit to the rectifier circuit and output as DC power. By using the heat sink in this way, it is possible to efficiently harvest power from the electrical equipment.

[0008] The power generating device may further include a high-pass filter provided between the heat sink connected to the transmission section and a ground of the electrical device.

[0009] The high-pass filter may pass AC components in a frequency band higher than the frequency band rectified by the rectifier circuit.

[0010] The rectifier circuit may have a pair of input terminals. In this case, the transmission unit may connect different heat sinks to the pair of input terminals, respectively, or may connect the heat sink to one of the pair of input terminals.

[0011] The transmission section may electrically connect the input terminal and the heat sink.

[0012] The power generation device may further include a high-pass filter provided between the heat sink connected to the transmission unit and a ground of the electrical device. In this case, the transmission unit may connect different heat sinks to the pair of input terminals. The high-pass filter may be provided on at least one of the heat sinks connected to the pair of input terminals.

[0013] The transmission section may connect the heat sink to one of the pair of input terminals and connect the other of the pair of input terminals to a GND of the electrical device directly or via a capacitor.

[0014] The electrical device may have a primary circuit to which power is supplied from a predetermined power source and a secondary circuit electrically isolated from the primary circuit, in which case the at least one heat sink may be provided in the primary circuit, and the rectifier circuit may be provided in the secondary circuit.

[0015] The transmission section may have a transformer, and the input terminal and the heat sink may be connected via the transformer.

[0016] The power generation device may further include a high-pass filter provided between the heat sink connected to the transmission unit and a ground of the electrical device. In this case, the transmission unit may connect different heat sinks to the pair of input terminals. The high-pass filter may be provided on one of the heat sinks connected to the pair of input terminals.

[0017] The transmission section may connect the heat sink to one of the pair of input terminals, and connect the other of the pair of input terminals to a GND of the electrical device via a capacitor.

[0018] The transmission unit may include an insulating sheet disposed in contact with the heat sink, and a conductive sheet connected to the heat sink by capacitive coupling via the insulating sheet, in which case the input terminal may be connected to the conductive sheet.

[0019] The at least one heat sink may include a plurality of heat sinks. In this case, the transmission unit may have a conductive member that electrically connects two or more of the plurality of heat sinks, and the two or more heat sinks connected by the conductive member may be connected to the input terminal.

[0020] The power generating device may further include a power storage unit having a power storage element that stores DC power output from the rectifier circuit and that controls charging or discharging of the power storage element depending on the charging state of the power storage element.

[0021] The power storage element may be a battery. In this case, the power storage unit may include a charge control unit that is provided between the battery and the rectifier circuit and that charges the battery in accordance with a charging state of the battery.

[0022] The power storage element may be a battery. In this case, the power storage unit may include a first switch element provided between the battery and the rectifier circuit, and a first switching control unit that switches the first switch element OFF when the voltage of the battery becomes equal to or higher than a first threshold voltage.

[0023] The power storage element may be a capacitor. In this case, the power storage unit may include a second switch element provided between the capacitor and a load to which power from the capacitor is supplied, and a second switching control unit that switches the second switch element ON when a voltage of the capacitor becomes equal to or higher than a second threshold voltage.

[0024] The power generating device may further include the at least one heat sink.

[0025] The electrical equipment may be industrial equipment.

[0026] According to an embodiment of the present technology, there is provided an electrical device including at least one heat sink and a power generating device, the at least one heat sink having a potential different from that of a ground (GND), the power generating device including a transmission unit connected to the at least one heat sink directly or by capacitive coupling and configured to transmit AC power of electromagnetic noise generated on the at least one heat sink, and a rectifier circuit configured to rectify the AC power transmitted by the transmission unit and output DC power.

[0027] A power generating device according to an embodiment of the present technology includes a transmission unit and a rectifier circuit. The transmission unit is connected directly or by capacitive coupling to at least one metal body provided in an electrical device and having a potential different from that of the earth GND, and transmits AC power of electromagnetic noise generated in the at least one metal body. The rectifier circuit rectifies the AC power transmitted by the transmission unit and outputs DC power.

[0028] The rectifier circuit may have a pair of input terminals. In this case, the at least one metal body may include at least one of a first metal body provided in a first electrical device or a second metal body provided in a second device different from the first device. Furthermore, the transmission unit may connect the first metal body to one of the pair of input terminals and the second metal body to the other of the pair of input terminals.

[0029] The first electric device and the second electric device may each include a noise source that generates the electromagnetic noise.

[0030] The transmission section may connect the first metal body and the second metal body to the pair of input terminals via a signal cable connecting the first electric device and the second electric device.

[0031] The transmission section may connect the first metal body and the second metal body to the pair of input terminals via a GND line of the signal cable.

[0032] The power generation device may be configured as any one of a cable unit including the signal cable, a relay unit that relays the signal cable, and a connector unit to which the signal cable is connected in the electrical device.

[0033] The power generation device may be provided on a third electric device to which the first electric device is connected via a first signal cable and the second electric device is connected via a second signal cable. In this case, the transmission unit may connect the first metal body to one of the pair of input terminals via the first signal cable and connect the second metal body to the other of the pair of input terminals via the second signal cable.

[0034] The transmission section may have a first transmission line connected to the first metal body, a second transmission line connected to the second metal body, and an inductor element provided between the first transmission line and the second transmission line.

[0035] The inductor element may have a Q value of 10 or greater in the frequency band to be harvested.

[0036] The at least one metal body may include a heat sink that is provided in the electrical device and has a different potential from the GND of the electrical device.

[0037] The power generation device may further include a storage element that stores DC power output from the rectifier circuit, and a selector switch that selects and connects either the storage element or a power supply unit provided in the electrical device to the load.

[0038] The changeover switch may connect the storage element to the load when the voltage of the storage element reaches a predetermined voltage or when a predetermined signal is output from the electrical appliance.

[0039] 6 is a schematic diagram showing an example of a configuration of a power generating device according to a first embodiment of the present technology; FIG. 2 is a block diagram showing an example of a functional configuration of the power generating device shown in FIG. 1; FIG. 3 is a schematic diagram showing an example of a noise countermeasure for a heat sink given as a comparative example; FIG. 4 is a schematic diagram showing another example of a noise countermeasure for a heat sink given as a comparative example; FIG. 5 is a schematic diagram showing an example of a connection of a heat sink used in a power generating device; FIG. 6 is a schematic diagram showing an example of a high-pass filter; FIG. 7 is a graph showing frequency characteristics of a transmission line provided with the high-pass filter shown in FIG. 6; FIG. 8 is a schematic diagram showing another example of a high-pass filter; FIG. 9 is a schematic diagram showing another example of a configuration of a power generating device according to the present embodiment; FIG. 10 is a schematic diagram showing another example of a configuration of a power generating device according to the present embodiment; 29 is a schematic diagram showing a configuration example of a power generation device according to a second embodiment. FIG. 30 is a block diagram showing a functional configuration example of the power generation device shown in FIG. 19. FIG. 31 is a schematic diagram showing a configuration example of a power supply board including a primary side circuit and a secondary side circuit. FIG. 32 is a schematic diagram showing another configuration example of a power generation device according to the present embodiment. FIG. 33 is a schematic diagram showing another configuration example of a power generation device according to the present embodiment. FIG. 34 is a graph showing the charging characteristics of a battery by a power generation device. FIG. 35 is a graph showing the discharging characteristics of a battery by a power generation device. FIG. 36 is a schematic diagram showing an application example of a power generation device. FIG. 37 is a schematic diagram showing an example of a configuration of a power generation device according to a third embodiment. FIG. 38 is a graph showing the noise characteristics of a heat sink provided in the primary side circuit. FIG. 39 is a schematic diagram showing the circuit configuration of a power generation device using a heat sink in the primary side circuit. FIG. 39 is a graph showing the discharging characteristics of a battery charged using the power generation device shown in FIG. 29. FIG. 39 is a schematic diagram showing the circuit configuration of a power generation device with impedance matching. FIG. 31 is a graph showing the discharging characteristics of a battery charged using the power generation device shown in FIG. 33. 1 is a schematic diagram showing an example of the configuration of a power generation device that uses a metal body of an electrical device.FIG. 1 is a schematic diagram showing an example of the configuration of a power generation device using a signal cable. FIG. 2 is a schematic diagram showing another example of the configuration of a power generation device using a signal cable. FIG. 3 is a schematic diagram showing another example of the configuration of a power generation device using a signal cable. FIG. 4 is a schematic diagram showing an example of the configuration of a power generation device in which an inductor element is provided between transmission lines. FIG. 5 is a schematic diagram showing an example of a measurement of power harvest yield depending on the Q value of an inductor element. FIG. 6 is a table showing an example of the frequency characteristics of the Q value of an inductor. FIG. 7 is a measurement result of power harvest yield depending on the Q value of the inductor element. FIG. 8 is a schematic diagram showing an example of the configuration of a power generation device using a power cable. FIG. 9 is a schematic diagram showing an example of a configuration of a power cable unit including a power generation device. FIG. 10 is a block diagram showing another example of the configuration of a power generation device. FIG. 11 is a flowchart showing an example of power supply operation using a storage element of a power generation device. FIG. 12 is a flowchart showing another example of power supply operation using a storage element of a power generation device.

[0040] Hereinafter, embodiments of the present technology will be described with reference to the drawings.

[0041] [Power Generation Device] Fig. 1 is a schematic diagram showing a configuration example of a power generation device according to a first embodiment of the present technology. Fig. 2 is a block diagram showing a functional configuration example of the power generation device 100 shown in Fig. 1. The power generation device 100 is a device that harvests power from a heat sink 10 provided in an electrical device 1.

[0042] The electrical device 1 is a device that operates using power supplied from, for example, an external power source or a battery. Fig. 1 schematically illustrates a circuit board 2 that constitutes the electrical device 1. Various semiconductor elements 3 are mounted on the circuit board 2. In addition, a ground pattern 4 that serves as the GND for the electrical device 1 is formed on the circuit board 2.

[0043] If the semiconductor elements 3, such as transistors and CPUs, used in the electrical device 1 are not cooled during operation, the heat generated by the semiconductor elements 3 may destroy the semiconductor elements 3 themselves. For this reason, heat is dissipated from the semiconductor elements 3 using a heat sink 10 inside the electrical device 1. Such semiconductor elements 3 not only generate heat during operation, but also emit various electromagnetic noises (see FIG. 3).

[0044] As a result, the heat sink 10 is subjected to electromagnetic noise emitted from the semiconductor element 3. The power generating device 100 disclosed herein efficiently converts the electromagnetic noise generated in the heat sink 10 back into electricity. In other words, the power generating device 100 can be said to be a device that achieves energy harvesting, primarily targeting electromagnetic noise.

[0045] 1 and 2, the power generating device 100 includes a heat sink 10, a transmission unit 20, a rectifier circuit 30, and a power storage unit 40. The power generating device 100 is configured to supply power to a load 90 provided downstream. Note that the power storage unit 40 is not shown in FIG.

[0046] The heat sink 10 is a member that is provided in close contact with or in contact with the semiconductor element 3 in the electrical device 1, and that dissipates heat generated by the semiconductor element 3 into the surrounding space to cool the semiconductor element 3. The heat sink 10 is typically made of a highly conductive material such as a metal material.

[0047] The heat sink 10 and the semiconductor element 3 are basically in close contact or insulated from each other. Methods for closely contacting the heat sink 10 to the semiconductor element 3 include, for example, adhesive bonding, screw fastening, spring fastening, etc. Alternatively, the circuit board 2 of the electrical device 1 may be used as a support member to fix the heat sink 10 and the semiconductor element 3 in close contact with each other. Other methods for closely contacting or insulating the heat sink 10 and the semiconductor element 3 are not limited thereto.

[0048] In this embodiment, the material of the heat sink 10 includes at least one of aluminum, copper, iron, and tin. For example, by using aluminum, the weight of the heat sink 10 can be reduced. Furthermore, by using copper, the thermal conductivity of the heat sink 10 can be improved, thereby improving cooling efficiency. Furthermore, by using a heat sink 10 made of tinplate, which is an iron material plated with tin, it becomes possible to easily perform soldering or the like on the heat sink 10. Other than these, the material of the heat sink 10 is not limited.

[0049] The power generating device 100 disclosed in the present disclosure uses at least one heat sink 10 having a potential different from that of the GND (ground pattern 4) of the electrical device 1. In other words, the heat sink 10 used in the power generating device 100 is not short-circuited to the ground pattern 4 and is configured so as not to have substantially the same potential as the GND potential of the ground pattern 4.

[0050] In the power generation device 100 shown in FIG. 1 , two semiconductor elements 3 are mounted on a circuit board 2 of an electrical device 1, and a metal heat sink 10 is provided on each semiconductor element 3 in close contact with the semiconductor element 3. Note that each heat sink 10 is not short-circuited to the GND of the electrical device (such as the ground pattern 4 of the circuit board 2) and is configured in an electrically floating state. Hereinafter, the semiconductor element 3 on the left side of the drawing will be referred to as the first semiconductor element 3a, and the heat sink 10 provided on the first semiconductor element 3a will be referred to as the first heat sink 10a. The semiconductor element 3 on the right side of the drawing will be referred to as the second semiconductor element 3b, and the heat sink 10 provided on the second semiconductor element 3b will be referred to as the second heat sink 10b.

[0051] The number of heat sinks 10 used in the power generating device 100 is not limited, and the power generating device 100 can be configured with a single heat sink 10 (see FIGS. 11 and 12, etc.). The power generating device 100 can also be configured with three or more heat sinks 10 (see FIG. 10). In either case, the heat sinks 10 constituting the power generating device 100 are configured to have a different potential from the ground pattern 4. The electrical device 1 may be provided with a heat sink 10 that is short-circuited to the ground pattern 4 if it is not used as the power generating device 100.

[0052] The transmission unit 20 is directly connected to at least one heat sink 10 and transmits AC power of electromagnetic noise generated in at least one heat sink 10. In this embodiment, the transmission unit 20 has a transmission line 21 that transmits AC power of electromagnetic noise, and one end of the transmission line 21 is electrically connected to the heat sink 10. The other end of the transmission line 21 is connected to an input terminal 31 of the rectifier circuit 30.

[0053] The transmission line 21 may be, for example, a wiring pattern formed on the circuit board 2 of the electrical device 1, or a connection cable independent of the circuit board 2. The transmission line 21 may also be formed by combining both a wiring pattern and a connection cable. The method for directly connecting the transmission line 21 and the heat sink 10 is not limited. For example, the wiring pattern or the connection cable may be connected to the heat sink 10 by soldering. When connecting a connection cable, a screw terminal, a terminal using a leaf spring, or a crimp terminal may be used. Alternatively, a conductive pin may be extended from the heat sink 10 and directly connected to the wiring pattern formed on the circuit board 2.

[0054] As will be described later, the rectifier circuit 30 is provided with a pair of input terminals 31 (a first input terminal 31a and a second input terminal 31b). The input terminals 31 and the heat sink 10 are electrically connected by a transmission line 21. In this embodiment, the transmission unit 20 connects different heat sinks 10 to the pair of input terminals 31. In other words, the heat sink 10 connected to one input terminal 31 is a different heat sink 10 from the heat sink 10 connected to the other input terminal 31. This makes it possible to supply AC power independently generated by each heat sink 10 to the rectifier circuit 30, thereby enabling a sufficient increase in power harvesting efficiency.

[0055] 1 , a pair of input terminals 31 of a rectifier circuit 30 are connected to two heat sinks 10 floating from the GND of the electrical device 1 via transmission lines 21. Specifically, a first input terminal 31a is connected to a first heat sink 10a via a first transmission line 21a, and a second input terminal 31b is connected to a second heat sink 10b via a second transmission line 21b. Of these, the first transmission line 21a and the second transmission line 21b form a transmission unit 20. Note that the configuration is not limited to connecting a heat sink 10 to each of the pair of input terminals 31; for example, a configuration in which the heat sink 10 is connected to one of the pair of input terminals 31 is also possible (see FIGS. 11 and 12 , etc.).

[0056] The rectifier circuit 30 rectifies the AC power transmitted by the transmission unit 20 and outputs DC power. As shown in FIG. 1 , the rectifier circuit 30 has a pair of input terminals 31 and a pair of output terminals 32. The pair of input terminals 31 includes a first input terminal 31a and a second input terminal 31b. There is no functional distinction between the first input terminal 31a and the second input terminal 31b. The pair of output terminals 32 includes a first output terminal 32a and a second output terminal 32b. Here, the first output terminal 32a outputs a positive voltage, and the second output terminal 32b is connected to a reference potential (e.g., GND potential). The specific configuration of the rectifier circuit 30 will be described in detail later.

[0057] 2 , the power storage unit 40 has a power storage element 55 that stores DC power output from the rectifier circuit 30, and supplies power from the power storage element 55 to a circuit that serves as a load 90 provided downstream. A capacitor or a battery is used as the power storage element 55. Note that the specific configuration of the power storage element 55 is not limited, and any element that can store power can be used as the power storage element 55.

[0058] Furthermore, in the power storage unit 40, the charging of the power storage element 55 is controlled in accordance with the charging state of the power storage element 55. This allows optimal charging of the power storage element 55. Alternatively, the power storage unit 40 may be configured to control the discharging of the power storage element 55 in accordance with the charging state of the power storage element 55. This allows appropriate power supply in accordance with the charging state. The configuration of the power storage unit 40 will be described later with reference to Figures 16, 17, 18, etc.

[0059] As described above, the heat sink 10 used in the power generating device 100 in the present disclosure is configured to have a potential different from the GND of the electrical device 1, and therefore functions as an antenna that receives electromagnetic noise from the semiconductor element 3. Therefore, the power generating device 100 has a structure in which the heat sink 10 that constitutes the antenna is connected to the rectifier circuit 30 via the transmission unit 20.

[0060] The electromagnetic noise received by the heat sink 10, which functions as an antenna, has an AC component, but the energy of the electromagnetic noise is output as DC power by passing through the rectifier circuit 30. The DC power output from the rectifier circuit 30 is stored in the power storage element 55 of the power storage unit 40. In this way, by making the heat sink 10 function as an antenna, it is possible to directly harvest the electromagnetic noise generated in the heat sink 10 and convert it into electric power.

[0061] 1 , both the first heat sink 10a and the second heat sink 10b function as antennas, and electromagnetic noise generated on both heat sinks 10 can be harvested as power. This significantly increases the amount of power that can be harvested compared to, for example, harvesting power between one heat sink 10 and the GND of the electrical device 1. In this way, with this technology, the heat sinks 10 that function as antennas can be connected to both of a pair of input terminals 31 of the rectifier circuit 30, making it possible to efficiently harvest power.

[0062] Here, the circuit configuration of the electrical device 1 will be described. The electrical device 1 has a primary circuit to which power is supplied from a predetermined power source, and a secondary circuit electrically isolated from the primary circuit. For example, the primary circuit is a circuit that is connected to a power line such as a commercial power source and adjusts the power supplied from the power line to the power required to operate the electrical device 1. The secondary circuit is a circuit that operates the electrical device 1 using the power adjusted by the primary circuit.

[0063] Such primary and secondary circuits are configured to be electrically isolated in accordance with safety standards, and therefore power is transferred and grounded between the primary and secondary circuits via a transformer.

[0064] In this embodiment, the transmission unit 20 is configured to electrically connect the input terminal 31 of the rectifier circuit 30 and the heat sink 10. In other words, the heat sink 10 and the rectifier circuit 30 are not electrically separated, and are not connected via a transformer. In order to achieve this configuration, the heat sink 10 and the rectifier circuit 30 are both provided on the same side of the primary side circuit or the secondary side circuit.

[0065] For example, when a heat sink 10 is used that is in close contact with a semiconductor element 3 provided in a secondary circuit, the rectifier circuit 30 and the power storage unit 40 provided thereafter are provided in the secondary circuit. When the heat sink 10 is in the primary circuit, the rectifier circuit 30 and the power storage unit 40 are also provided in the primary circuit. This makes it possible to achieve efficient and safe energy harvesting.

[0066] [General Electromagnetic Noise Countermeasures] Figure 3 is a schematic diagram showing an example of a noise countermeasure for a heat sink, given as a comparative example. Figure 3 schematically illustrates a semiconductor element 3 and a heat sink 92 to which noise countermeasures have been implemented. As described above, the semiconductor element 3 and the heat sink 92 are tightly attached with adhesive or screws. At this time, the semiconductor element 3 and the heat sink 92 are electrically separated (insulated) so that wiring and the like of the semiconductor element 3 do not short-circuit to the heat sink 92. Therefore, the two are connected by capacitive coupling. Figure 3 also schematically illustrates a virtual capacitor representing the capacitive coupling between the semiconductor element 3 and the heat sink 92.

[0067] Here, a switching transistor 5 that converts voltage will be described as an example of a semiconductor element 3. Inside the electrical device 1, the switching transistor 5 (semiconductor element 3) converts the supplied voltage into the voltage used by the device, and generates heat to generate the desired voltage through switching. Heat 15 (indicated by the broken line arrow in the figure) generated by the switching transistor 5 is dissipated by contact with a heat sink 92.

[0068] Furthermore, electromagnetic noise 16 of various frequencies is generated from the switching transistor 5 when it performs switching. For example, it is known that noise components such as noise according to the switching cycle, ripple noise, and spike noise are generated, and electromagnetic waves containing various frequency components (wave lines with different periods in the figure) are emitted from the switching transistor 5 as electromagnetic noise 16. This electromagnetic noise 16 is received by a heat sink 92 that is in close contact with the switching transistor 5. As a result, electromagnetic noise 16 containing various frequency components is generated at the heat sink 92.

[0069] A common countermeasure against such electromagnetic noise 16 is to connect the heat sink 92 to the GND (ground pattern 4) of the electrical device 1 to allow the electromagnetic noise 16 to escape. In the example shown in Fig. 3, the heat sink 92 and the ground pattern 4 are electrically connected by a short-circuit wire 93. As a result, the AC electromagnetic noise 16 generated in the heat sink 92 flows directly into the ground pattern 4 via the short-circuit wire 93, and the energy of the electromagnetic noise 16 is absorbed by the GND of the electrical device 1.

[0070] 4A and 4B are schematic diagrams showing another example of noise suppression in a heat sink, given as a comparative example. Here, a method of using a shield plate 96 to dissipate electromagnetic noise 16 to GND will be described. Fig. 4A is a schematic diagram showing an example of connection between a semiconductor element 3 (switching transistor 5) and a heat sink 94 with noise suppression measures, and Fig. 4B is a circuit diagram of the configuration shown in Fig. 4A.

[0071] The shield plate 96 is a conductive plate (typically a metal plate) for shielding electromagnetic noise 16. As shown in Fig. 4A, the shield plate 96 is sandwiched between an insulating member 95 and provided between the semiconductor element 3 and the heat sink 94. Therefore, as shown in Fig. 4B, the connection between the semiconductor element 3 and the shield plate 96 and the connection between the shield plate 96 and the heat sink 94 are both capacitively coupled. The shield plate 96 is also connected to the GND (ground pattern 4) of the electrical device 1, and a noise return circuit 97 is formed as shown in Fig. 4B.

[0072] As a result, the shield plate 96 has the same potential as the ground pattern 4 and functions as an electromagnetic shield. As a result, the generation of electromagnetic noise 16 in the heat sink 94 is suppressed. Note that in Figures 4A and 4B, the heat sink 94 may be connected to the ground pattern 4 to allow the electromagnetic noise 16 to escape. As a result, in addition to the effect of the shield plate 96, the electromagnetic noise 16 generated in the heat sink 94 is sufficiently suppressed.

[0073] In this way, electromagnetic noise 16 generated by semiconductor elements 3 such as switching transistors is generally returned to the GND (ground pattern 4) of electrical equipment 1 by implementing noise countermeasures such as those shown in Figures 3 and 4. In this case, the energy of electromagnetic noise 16 escapes to the GND and cannot be harvested from heat sinks 92 and 94.

[0074] [Harvesting of Electromagnetic Noise] In contrast, the power generation device 100 according to the present disclosure does not return the energy of the electromagnetic noise 16 generated by the semiconductor element 3 to the GND (ground pattern 4) of the electrical equipment, but instead converts the energy into electricity again and utilizes it.

[0075] 5A and 5B are schematic diagrams showing connection examples of the heat sink 10 used in the power generating device 100. Fig. 5A shows a connection example in which the heat sink 10 is in close contact with the semiconductor element 3 without providing a shield plate 96, and Fig. 5B shows a connection example in which the heat sink 10 is in close contact with the semiconductor element 3 via the shield plate 96. The heat sinks 10 shown in Figs. 5A and 5B are both configured to have a potential different from the GND of the electrical device 1 so as to function as antennas, and are used here in a state floating from the ground pattern 4.

[0076] 5A , in a configuration in which the heat sink 10 is in close contact with the semiconductor element 3 via an insulating member 95, the heat sink 10 is connected to the input terminal 31 of the rectifier circuit 30 via the transmission section 20. In this case, the heat sink 10 receives the electromagnetic waves emitted from the semiconductor element 3, generating electromagnetic noise 16 in the heat sink 10. This electromagnetic noise 16 is transmitted to the rectifier circuit 30 and converted into DC power. Furthermore, because the heat sink 10 is not connected to the ground pattern 4, it is possible to convert the energy of the electromagnetic noise 16 into power without letting it escape.

[0077] 5B shields the semiconductor element 3 from electromagnetic noise and also functions to dissipate heat generated by the semiconductor element 3, similar to the heat sink 10 provided downstream. Therefore, the shield plate 96 can be considered to be part of the heat sink 10. When the shield plate 96 is provided in this manner, the shield plate 96 is connected to the input terminal 31 of the rectifier circuit 30 via the transmission unit 20. In this case, the shield plate 96 receives most of the electromagnetic waves emitted from the semiconductor element 3, causing electromagnetic noise 16 to be generated on the shield plate 96. This electromagnetic noise 16 is transmitted to the rectifier circuit 30 and converted into DC power.

[0078] Furthermore, the heat sink 10 provided downstream of the shield plate 96 may be connected to the input terminal 31 of the rectifier circuit 30. This allows the downstream heat sink 10, in addition to the upstream shield plate 96, to function as an antenna that receives the electromagnetic noise 16, making it possible to fully harvest the energy of the electromagnetic noise 16. Note that when the shield plate 96 is provided, the downstream heat sink 10 does not necessarily need to be connected to the rectifier circuit 30, and may be connected to the ground pattern 4, for example.

[0079] In this way, the power generating device 100 harvests the electromagnetic noise 16 and converts it into electricity, so that the electromagnetic noise 16 can be suppressed without being released to the ground pattern 4. In other words, the connection methods shown in Figures 1 and 5 also function as a means for suppressing the electromagnetic noise 16 emitted from the semiconductor element 3. Therefore, for example, if the electromagnetic noise 16 can be suppressed to a required level, the connection methods shown in Figures 1 and 5 can also be used to achieve noise countermeasures.

[0080] [High-pass filter] The above description has been made on a configuration in which all frequency components of the electromagnetic noise 16 generated in the heat sink 10 are transmitted directly to the rectifier circuit 30. However, due to the characteristics of the diodes constituting the rectifier circuit 30, it may be difficult to rectify high-frequency components exceeding a certain frequency. Such high-frequency components may be returned to the GND of the electrical device 1. In this case, a high-pass filter is provided in the power generation device 100.

[0081] 6 is a schematic diagram showing an example of a high-pass filter. The high-pass filter 50 is a filter that passes frequency components higher than a threshold frequency and suppresses frequency components lower than the threshold frequency. The high-pass filter 50 is provided between the heat sink 10 connected to the transmission unit 20 (transmission line 21) and the GND (ground pattern 4) of the electrical device 1.

[0082] 6 is a filter composed only of a capacitor 51. One end of the capacitor 51 is connected to the transmission line 21 connecting the heat sink 10 and the rectifier circuit 30, and the other end of the capacitor 51 is connected to the ground pattern 4. As a result, of the frequency components flowing through the transmission line 21, those higher than the threshold frequency pass through the high-pass filter 50 (capacitor 51) and flow to the ground pattern 4. Furthermore, the frequency components flowing through the transmission line 21, i.e., the frequency components transmitted from the heat sink 10 to the rectifier circuit 30, are frequency components equal to or lower than the threshold frequency.

[0083] As described above, it may be difficult for the rectifier circuit 30 to rectify frequency components above a certain frequency. Therefore, components in a frequency band that can be rectified using the rectifier circuit 30 are targets for harvesting by the power generation device 100, but components in other high frequency bands are noise components that cannot be harvested by the power generation device 100.

[0084] Therefore, in this embodiment, the high-pass filter 50 is configured to pass AC components in a frequency band higher than the frequency band rectified by the rectifier circuit 30. In other words, the high-pass filter 50 is configured to pass AC components (noise components) excluding the frequency band to be harvested. For example, the threshold frequency of the high-pass filter 50 is set to the upper limit of the frequency band rectified by the rectifier circuit 30.

[0085] By configuring the high-pass filter 50 in this manner, the impedance with the ground pattern 4 becomes high in the frequency band to be harvested, and becomes low in other frequency bands. As a result, all noise components that are not to be harvested can be diverted to the ground pattern 4. Furthermore, components in the frequency band to be harvested can be supplied to the rectifier circuit 30 and harvested as power. This makes it possible to efficiently harvest power while sufficiently suppressing unnecessary noise components.

[0086] Fig. 7 is a graph showing the frequency characteristics of the transmission line 21 provided with the high-pass filter 50 shown in Fig. 6. The horizontal axis of the graph represents frequency (Hz), and the vertical axis represents the intensity (dB) of the frequency component that flows from the heat sink 10 to the rectifier circuit 30 and passes through the transmission line 21. Here, the frequency at which the intensity of the frequency component passing through the transmission line 21 is -3 dB is referred to as the threshold frequency f0 of the high-pass filter 50.

[0087] 7, the transmission line 21 equipped with the high-pass filter 50 passes frequency components below the threshold frequency f0 with almost no attenuation. On the other hand, frequency components above the threshold frequency f0 are more suppressed as the frequency increases. In this way, the transmission line 21 equipped with the high-pass filter 50 exhibits the characteristics of a low-pass filter that passes low-frequency components and suppresses high-frequency components.

[0088] Here, the upper limit of the frequency band rectified by the rectifier circuit 30 (the frequency band to be harvested) is set to 100 MHz. Therefore, the high-pass filter 50 is configured so that the threshold frequency f0 is 100 MHz. In the high-pass filter 50 shown in FIG. 6, the capacitance of the capacitor 51 is set to 100 μF to achieve f0 = 100 MHz. Note that the threshold frequency f0 of the high-pass filter 50 is not limited to the above example, and the threshold frequency f0 can be determined appropriately based on the frequency band to be harvested (the characteristics of the rectifier circuit 30) and EMC measures.

[0089] 8 is a schematic diagram showing another example of a high-pass filter. The high-pass filter 50 shown in FIG. 8 is configured as a parallel circuit of a capacitor 52 and a resistor 53. Specifically, one end of the capacitor 52 is connected to the heat sink 10, and the other end of the capacitor 52 is connected to the ground pattern 4. Similarly, one end of the resistor 53 is connected to the heat sink 10, and the other end of the resistor 53 is connected to the ground pattern 4.

[0090] With this configuration, the capacitor 52 and the resistor element 53 can consume excess high-frequency components (noise components), thereby providing EMC measures and measures against high-voltage ringing. The measure against high-voltage ringing is to suppress antenna radiation caused by ringing noise generated in the heat sink 10, for example. For example, by using the resistor element 53, it is possible to consume the power of relatively high-voltage ringing noise, etc., by generating heat, thereby suppressing antenna radiation.

[0091] There are no other limitations on the configuration of the high-pass filter 50. For example, the high-pass filter 50 shown in Fig. 8 may be configured with only either the capacitor 52 or the resistor element 53. Furthermore, the high-pass filter 50 may be configured by combining any other element, such as an inductor, in addition to the capacitor 52 and the resistor element 53.

[0092] 9 is a schematic diagram showing another example of the configuration of a power generation device according to this embodiment. The power generation device 100a shown in FIG. 9 includes a high-pass filter 50 as the above-described noise countermeasure. The transmission unit 20 (transmission line 21) of the power generation device 100a connects different heat sinks 10 to a pair of input terminals 31 of the rectifier circuit 30. The high-pass filter 50 is provided on at least one of the heat sinks 10 connected to the pair of input terminals 31.

[0093] 9, a high-pass filter 50 including a capacitor 52 is provided between the first heat sink 10a on the left side of the drawing and the ground pattern 4. The type of high-pass filter 50 is not limited to this, and a parallel circuit of a capacitor 52 and a resistor element 53 (see FIG. 8) or the like may also be used.

[0094] In a configuration in which the heat sink 10 is connected to the rectifier circuit 30, the electromagnetic noise 16 can be harvested and converted into electricity, thereby reducing noise. For example, in FIG. 9, the second heat sink 10b on the right side of the figure is floating above the ground pattern 4 without a high-pass filter 50, as it is believed that the effect of harvesting the electromagnetic noise 16 can sufficiently reduce noise. In this way, it is not necessary to provide a high-pass filter 50 on the heat sink 10 connected to the rectifier circuit 30. In cases where a large amount of noise that cannot be harvested is generated, high-pass filters 50 may be provided on both heat sinks 10.

[0095] Fig. 10 is a schematic diagram showing another example of the configuration of the power generation device according to this embodiment. The power generation device 100b shown in Fig. 10 is an example in which two or more heat sinks 10 are connected to one input terminal 31 of the rectifier circuit 30. The transmission section 20 of the power generation device 100b has a conductive member 12 that electrically connects the two or more heat sinks 10, and the two or more heat sinks 10 connected by the conductive member 12 are connected to the input terminal 31.

[0096] 1, the circuit board 2 shown in Fig. 10 includes a third semiconductor element 3c on the left side of the first semiconductor element 3a. A third heat sink 10c is provided in close contact with the third semiconductor element 3c. The third heat sink 10c is not short-circuited to the ground pattern 4 and is in a floating state.

[0097] In this case, the first heat sink 10a and the third heat sink 10c are electrically connected by a conductive member 12. The conductive member 12 is, for example, a metal sheet or a metal cable. This allows the first heat sink 10a and the third heat sink 10c to be regarded as a single large heat sink 10. The first heat sink 10a and the third heat sink 10c connected by the conductive member 12 are connected to a first input terminal 31a of the rectifier circuit 30 via a first transmission line 21a connected to the first heat sink 10a.

[0098] In addition to the electromagnetic noise 16 generated on the first heat sink 10a, the electromagnetic noise 16 generated on the third heat sink 10c is also input to the first input terminal 31a. This makes it possible to significantly increase the amount of harvested power. In this way, the power generation device 100b is an example in which multiple heat sinks 10 generating electromagnetic noise 16 are combined into one by connecting them with conductive members 12, thereby increasing the amount of harvested power.

[0099] The number of heat sinks 10 connected via the conductive member 12 is not limited, and for example, three or more heat sinks 10 may be connected to the input terminal 31. In addition, in the example shown in FIG. 10, the heat sink 10 connected to the first input terminal 31a is connected, but it is also possible to connect the heat sink 10 connected to the second input terminal 31b. Of course, the heat sink 10 may be connected to both the first input terminal 31a and the second input terminal 31b. Note that the heat sink 10 connected to one input terminal 31 is not connected to the heat sink 10 connected to the other input terminal 31.

[0100] 11 and 12 are schematic diagrams showing other configuration examples of the power generation device according to this embodiment. The power generation device 100c shown in Fig. 11 and the power generation device 100d shown in Fig. 12 are both examples in which the heat sink 10 is connected to only one input terminal 31 of the rectifier circuit 30.

[0101] 11, the transmission unit 20 of the power generation device 100c has a heat sink 10 connected to one of a pair of input terminals 31, and electrically connects the GND (ground pattern 4) of the electrical device 1 to the other of the pair of input terminals 31. In the example shown in FIG. 11, the first input terminal 31a is connected to the heat sink 10, and the second input terminal 31b is directly connected to the ground pattern 4.

[0102] 12, the transmission unit 20 of the power generation device 100d has a pair of input terminals 31 to which the heat sink 10 is connected, and the other input terminal 31 to which the GND (ground pattern 4) of the electrical device 1 is connected via a capacitor 22. In the example shown in FIG. 12, the first input terminal 31a is connected to the heat sink 10, and the second input terminal 31b is connected to the ground pattern 4 via the capacitor 22.

[0103] In this way, when the heat sink 10 is connected to only one of the input terminals 31 of the rectifier circuit 30, the other input terminal 31 is connected directly or by capacitive coupling to the GND of the electrical device 1. With this configuration, it is possible to harvest AC power of the electromagnetic noise 16 from the heat sink 10 connected to one of the input terminals 31. For example, this configuration may be adopted when there is only one heat sink 10 available for energy harvesting.

[0104] [Rectifier Circuit] Fig. 13 is a circuit diagram showing an example configuration of a rectifier circuit 30. The rectifier circuit 30 rectifies AC power input from a pair of input terminals 31. In the rectifier circuit 30 shown in Fig. 13, a first heat sink 10a is connected to a first input terminal 31a, and a second heat sink 10b is connected to a second input terminal 31b. Note that the configuration shown in Fig. 13 can be used even when a heat sink 10 is connected to only one of the first input terminal 31a and the second input terminal 31b.

[0105] In terms of efficiency of the rectifier circuit 30, for example, a full-wave rectifier circuit can increase the voltage of the AC signal and absorb the entire signal, so it is efficient even when including the loss of the diodes used for rectification. It is also important that the rectifier circuit 30 has very little leakage current from the diodes when reverse biased, but if leakage current is present, a full-wave rectifier circuit is suitable. From these points of view, it is preferable to use a full-wave rectifier circuit as the rectifier circuit 30. The configuration of the rectifier circuit 30 is not limited, and a half-wave rectifier circuit, a voltage doubler circuit, a Cockcroft-Walton circuit, etc. may also be used.

[0106] The rectifier circuit 30 shown in Figure 13 is configured as a full-wave rectifier circuit. The rectifier circuit 30 has a first input terminal 31a, a second input terminal 31b, four diodes 33a, 33b, 33c, and 33d, a Zener diode 34, and a first output terminal 32a and a second output terminal 32b. The diodes 33a and 33b are connected in series, and the diodes 33c and 33d are connected in series. The connection point between the anode of the diode 33a and the cathode of the diode 33b forms a feed point 35a to which the first input terminal 31a is connected. The connection point between the anode of the diode 33c and the cathode of the diode 33d forms a feed point 35b to which the second input terminal 31b is connected.

[0107] The connection point between the cathode of diode 33a and the cathode of diode 33c is connected to first output terminal 32a, and the connection point between the anode of diode 33b and the anode of diode 33d is connected to second output terminal 32b. Rectifying diodes 33a, 33b, 33c, and 33d are configured as discrete diodes, but may also be configured as dedicated ICs.

[0108] A Zener diode 34 is connected in parallel between the output terminals 32a and 32b. The Zener diode 34 functions as an electrostatic protection component that releases static electricity when a high voltage such as static electricity occurs. A varistor for static electricity protection may be provided instead of the Zener diode 34. Note that an electrostatic protection component such as the Zener diode 34 may not be provided depending on the configuration of the power generation device 100.

[0109] FIG. 14 is a graph illustrating the characteristics of the diodes in the rectifier circuit 30. FIG. 15 is a table illustrating the characteristics of the diodes in the rectifier circuit 30. Measurement results of the forward voltage Vf and reverse current Is of the rectifier diodes used in the rectifier circuit 30 are shown in FIGS. 14 and 15. Measurements were performed on silicon and germanium diodes with part number 1N60, while evaluations were performed on germanium diodes from different manufacturers with part number 1SS108. In FIG. 14, curve 36a represents the characteristics of 1N60 (silicon), curve 36b represents the characteristics of 1N60 (germanium), and curve 36c represents the characteristics of 1SS108 (germanium).

[0110] The reverse current Is is the current that flows when a voltage is applied in the reverse direction of a diode. The measurement data in Figure 15 is data when 10 V is applied in the reverse direction of the diode. The forward voltage Vf is the voltage at which a forward current (1 mA) begins to flow through the diode.

[0111] When AC power from the heat sink 10 is rectified, it was found that the 1N60 (silicon) diode, which does not allow reverse current to flow, can absorb more power than a diode with a lower forward current flow voltage. The reverse current Is that occurs when the diode's forward voltage Vf is applied in the reverse direction was also evaluated. The rectified signal is AC, and Figure 15 shows data for 10V. The reverse current Is when a voltage equal to Vf is applied in the reverse direction is calculated to be 0.036 μA for the 1N60 (silicon), 0.21 μA for the 1N60 (germanium), and 0.5 μA for the 1SS108 (germanium).

[0112] Therefore, the ratio of forward current (1 mA) to reverse current Is at forward voltage Vf is 1 / 27778 for 1N60 (silicon), 1 / 4762 for 1N60 (germanium), and 1 / 2000 for 1SS108 (germanium). In other words, the diodes constituting the rectifier circuit 30 preferably have a ratio of forward current at forward voltage to reverse current when that voltage is applied in the reverse direction of 4700 or more. More preferably, the ratio is 10,000 or more. As a result, of the three example diodes, 1N60 (silicon) has the most suitable characteristics.

[0113] Furthermore, considering the characteristics of the diode, the smaller the reverse current Is when applied in the reverse direction, the better. Using data from 10V, the reverse resistance values ​​calculated are 100 MΩ for 1N60 (silicon), 1.43 MΩ for 1N60 (germanium), and 0.38 MΩ for 1SS108 (germanium). In other words, a high resistance value that blocks reverse current is preferable. The diodes that make up the rectifier circuit 30 preferably have a resistance value of 1.4 MΩ or greater, calculated from the reverse current when a reverse voltage of 10V is used. More preferably, the resistance value is 10 MΩ or greater. As a result, of the three example diodes, 1N60 (silicon) has the most suitable characteristics.

[0114] As described above, the diodes constituting the rectifier circuit 30 are preferably silicon diodes. By using silicon diodes, it is possible to realize a highly efficient rectifier circuit 30. Note that the diodes are not limited to the above examples, and it is possible to appropriately select diodes with low loss or diodes capable of rectifying high frequencies depending on the application and usage environment of the rectifier circuit 30. Furthermore, the rectifier circuit 30 may be constituted using switching elements such as FETs (Field Effect Transistors).

[0115] [Electricity Storage Unit] The following describes in detail the configuration of the electricity storage unit 40 that stores the DC power output from the rectifier circuit 30 in the electricity storage element 55. The configuration of the electricity storage unit 40 described here can be applied to any of the power generation devices described above.

[0116] Fig. 16 is a schematic circuit diagram showing an example configuration of a power storage unit. The power storage unit 40a shown in Fig. 16 includes a smoothing capacitor 41, a protection diode 42, a PMIC circuit 43, and a battery 56. Hereinafter, the line connected to the first output terminal 32a of the rectifier circuit 30 may be referred to as a first output line 45a, and the line connected to the second output terminal 32b may be referred to as a second output line 45b. The second output line 45b is, for example, a ground line connected to the GND of the electrical device 1.

[0117] The smoothing capacitor 41 is a capacitance element that smoothes the output of the rectifier circuit 30, and is provided between the first output line 45a and the second output line 45b at the subsequent stage of the rectifier circuit 30. By providing the smoothing capacitor 41, it is possible to reduce ripples and the like contained in the output of the rectifier circuit 30 and supply a stable DC component. The smoothing capacitor 41 also functions as a storage element that temporarily stores the DC power output from the rectifier circuit 30.

[0118] The protection diode 42 is an element for protecting the downstream IC circuit (here, the PMIC circuit 43) connected to the first output line 45a and the second output line 45b. The protection diode 42 is provided between the smoothing capacitor 41 and the downstream IC circuit, with its cathode connected to the first output line 45a and its anode connected to the second output line 45b. A Zener diode that conducts when a certain voltage is applied is used as the protection diode 42. This makes it possible to prevent damage to the downstream circuit.

[0119] The PMIC circuit 43 is a circuit that is provided between the battery 56 and the rectifier circuit 30 and charges the battery 56 depending on the charging status of the battery 56, and is configured using a power management IC (PMIC). In the example shown in Fig. 16, the PMIC circuit 43 is provided between the protection diode 42 and the battery 56, and is connected to a first output line 45a and a second output line 45b.

[0120] For example, the PMIC circuit 43 adjusts the voltage, current, etc. supplied to charge the battery 56 according to the voltage, etc., of the battery 56. Furthermore, a step-down charging circuit that charges by stepping down the output voltage of the rectifier circuit 30, or a step-up charging circuit that charges by stepping up the output voltage of the rectifier circuit 30, etc., may be appropriately selected according to the power that can be harvested from the heat sink 10. In addition, protection functions for the battery 56, including prevention of overcharging, etc., may also be implemented. In this embodiment, the PMIC circuit 43 corresponds to a charge control unit. Furthermore, the PMIC circuit 43 is an example of a control element for controlling the charging of the power storage element.

[0121] The battery 56 is a storage element 55 that stores the DC power output from the rectifier circuit 30. The positive electrode of the battery 56 is connected to the first output line 45a, and the negative electrode of the battery 56 is connected to the second output line 45b. The battery 56 supplies power to a downstream load 90 via the first output line 45a and the second output line 45b.

[0122] In the power storage unit 40a, the DC power output from the rectifier circuit 30 is supplied to the PMIC circuit 43. The PMIC circuit 43 appropriately detects the voltage of the battery 56 and appropriately adjusts the voltage for charging the battery 56 based on the detection result. This makes it possible to easily realize constant voltage charging, constant current charging, etc. of the battery 56.

[0123] Fig. 17 is a schematic circuit diagram showing another example of the configuration of the power storage unit. The power storage unit 40b shown in Fig. 17 has a smoothing capacitor 41, a protection diode 42, an ideal diode 46, a voltage detection IC 47, and a battery 56. The smoothing capacitor 41 and the protection diode 42 are configured in the same manner as the power storage unit 40a shown in Fig. 16.

[0124] The ideal diode 46 is a diode element that is switched on and off by a control signal, and is provided between the battery 56 and the rectifier circuit 30. Specifically, the ideal diode 46 is inserted on the first output line 45a between the battery 56 and the rectifier circuit 30. The rectifier circuit 30 side is the input end of the ideal diode 46, and the battery 56 side is the output end of the ideal diode 46.

[0125] The ideal diode 46 is, for example, an element in which a diode is connected in series after a switch element. The switch element is switched ON and OFF by a control signal input from the voltage detection IC 47. For example, when the switch element is ON, backflow from the output terminal to the input terminal is prevented, and when the switch element is OFF, the path connecting the input terminal and the output terminal is blocked. Therefore, it can be said that the ideal diode 46 is an element that has both a switch function and a backflow prevention function. In this embodiment, the ideal diode 46 corresponds to the first switch element.

[0126] The voltage detection IC 47 has a detection terminal 47d, a control terminal 47c, and a power supply terminal 47p. It is an IC circuit that detects voltage using the detection terminal 47d and outputs a control signal from the control terminal 47c in accordance with the detection result. The detection terminal 47d is connected to the first output line 45a (the positive electrode of the battery 56) downstream of the ideal diode 46. The control terminal 47c is connected to the ideal diode 46. The power supply terminal 47p is connected to the first output line 45a upstream of the ideal diode 46. The voltage detection IC 47 is also connected to the second output line 45b (GND) and detects the voltage at the detection terminal 47d as seen from the second output line 45b. Therefore, the voltage detected by the voltage detection IC is the voltage of the battery 56.

[0127] Furthermore, the voltage detection IC 47 switches the ideal diode 46 OFF when the voltage of the battery 56 becomes equal to or greater than the first threshold voltage V1. Specifically, when the voltage at the detection terminal 47d is less than the first threshold voltage V1, the voltage detection IC 47 outputs a control signal to turn the ideal diode 46 ON. Furthermore, when the voltage at the detection terminal 47d becomes equal to or greater than the first threshold voltage V1, the voltage detection IC 47 outputs a control signal to turn the ideal diode 46 OFF. In this embodiment, the voltage detection IC 47 corresponds to a first switching control unit. Furthermore, the ideal diode 46 and the voltage detection IC 47 are examples of control elements for controlling the charging of the storage element.

[0128] The first threshold voltage V1 is set to, for example, the voltage at which the battery 56 is fully charged. As a result, the ideal diode 46 is ON and charging of the battery 56 continues until the battery 56 is fully charged. However, once the battery 56 is fully charged, the ideal diode 46 is turned OFF and no voltage is applied to the battery 56.

[0129] In this way, the power storage unit 40b is configured so that the battery 56 is charged up to a certain voltage V1 and does not exceed that voltage, by combining the ideal diode 46 and the voltage detection IC 47. This makes it possible to prevent overcharging of the battery 56, charge the battery 56 appropriately, and extend the life of the battery 56.

[0130] Furthermore, the use of the ideal diode 46 can suppress power leakage from the battery 56. For example, with a single diode, if the voltage across its terminals changes and a reverse voltage is applied, some current may flow backward. In contrast, the ideal diode 46 can prevent the generation of reverse current by providing a switch element in the upstream stage of the diode. This makes it possible to avoid situations such as current leakage from the battery 56 provided in the downstream stage, and enables the output of the rectifier circuit 30 to be efficiently stored.

[0131] Fig. 18 is a schematic circuit diagram showing another example of the configuration of the power storage unit. The power storage unit 40c shown in Fig. 18 has a smoothing capacitor 41, a protection diode 42, a switch element 48, a voltage detection IC 49, and a storage capacitor 57. The smoothing capacitor 41 and the protection diode 42 are configured in the same manner as the power storage unit 40a shown in Fig. 16.

[0132] Unlike the above-described power storage units 40a and 40b, the power storage unit 40c uses a storage capacitor 57 as a storage element 55 that stores the DC power output from the rectifier circuit 30. There are no limitations on the type or capacity of the storage capacitor 57, and any capacitor may be used depending on the output of the rectifier circuit 30, the type of load, etc. The storage capacitor 57 is connected between the first output line 45a and the second output line 45b at the subsequent stage of the protection diode 42.

[0133] The switch element 48 is an element that switches the path between ON and OFF in response to a control signal, and is configured using an FET (Field Effect Transistor) or the like. The switch element 48 is provided between the storage capacitor 57 and a load 90 to which power from the storage capacitor 57 is supplied. Specifically, the switch element 48 is inserted on the first output line 45a between the storage capacitor 57 and the load 90. A control signal is input to the switch element 48 from a voltage detection IC 49. In this embodiment, the switch element 48 corresponds to a second switch element.

[0134] The voltage detection IC 49 has a detection terminal 49d, a control terminal 49c, and a power supply terminal 49p. The voltage detection IC 49 is an IC circuit that detects voltage via the detection terminal 49d and outputs a control signal from the control terminal 49c in accordance with the detection result. The detection terminal 49d and the power supply terminal 49p are connected to the first output line 45a between the protection diode 42 and the storage capacitor 57. The control terminal 49c is connected to the switch element 48. The voltage detection IC 49 is also connected to the second output line 45b (GND) and detects the voltage at the detection terminal 49d as seen from the second output line 45b. Therefore, the voltage detected by the voltage detection IC is the voltage across the storage capacitor 57.

[0135] Furthermore, the voltage detection IC 49 switches the switch element 48 ON when the voltage of the storage capacitor 57 becomes equal to or greater than the second threshold voltage V2. Specifically, when the voltage at the detection terminal 49 d is less than the second threshold voltage V2, the voltage detection IC 49 outputs a control signal to turn the switch element 48 OFF. Furthermore, when the voltage at the detection terminal 49 d becomes equal to or greater than the second threshold voltage V2, the voltage detection IC 49 outputs a control signal to turn the switch element 48 ON. In this embodiment, the voltage detection IC 49 corresponds to a second switching control unit. Furthermore, the switch element 48 and the voltage detection IC 49 are examples of control elements for controlling the discharge of the storage element.

[0136] The second threshold voltage V2 is set to, for example, the voltage when the storage capacitor 57 is sufficiently charged. As a result, when the storage capacitor 57 is not sufficiently charged, the switch element 48 is OFF, and the storage capacitor 57 continues to charge without being discharged. On the other hand, when the storage capacitor 57 is sufficiently charged, the switch element 48 is ON, and power is supplied from the storage capacitor 57 to the load 90. Note that the voltage detection IC 49 may be configured to output a control signal that turns ON the switch element 48 for a certain period of time. This makes it possible to prevent the discharge of the storage capacitor 57 from being completed instantaneously and to supply the required power.

[0137] In this way, in the power storage unit 40c using the storage capacitor 57, the switch element 48 provided downstream of the storage capacitor 57 is controlled by the voltage detection IC 49. As a result, when the voltage of the storage capacitor 57 reaches a certain voltage V2, the switch element 48 is switched ON, and power is intermittently supplied to the downstream load 90. In other words, a configuration is possible in which the required power is supplied to the load 90 each time power is accumulated in the storage capacitor 57.

[0138] As described above, in the power generation devices 100, 100a, 100b, 100c, and 100d according to the present embodiment, AC power of the electromagnetic noise 16 generated in the heat sink 10, which has a different potential from the GND of the electrical device 1, is transmitted by the transmission unit 20 to the rectifier circuit 30 and output as DC power. By using the heat sink 10 in this way, it is possible to efficiently harvest power from the electrical device 1.

[0139] Generally, among ICs and other devices within a device, ICs that generate a lot of noise are fitted with heat sinks in close contact with the IC to release heat and electromagnetic noise. However, such heat sinks are generally connected to the device's GND in some way to provide EMC protection. In this case, the electromagnetic noise generated by the heat sink escapes to the GND. This makes it difficult to harvest power from heat sinks that generate a lot of noise.

[0140] In this embodiment, the heat sink 10 is connected to the rectifier circuit 30 via the transmission unit 20. The heat sink 10 connected to the rectifier circuit 30 is either floating from the GND of the electrical device 1 or connected to the GND via a capacitor or resistor that constitutes the high-pass filter 50. Therefore, electromagnetic noise 16 generated in the heat sink 10 is transmitted to the rectifier circuit 30 without escaping to the GND. This makes it possible to rectify the energy of the relatively large electromagnetic noise 16 generated in the heat sink 10 and capture it as electric power. As a result, it becomes possible to efficiently harvest electric power from the electrical device 1 that has a large noise component.

[0141] Furthermore, various cables (such as a television coaxial cable, a LAN cable, or a USB cable) may be inserted into the electrical device 1, and connecting these cables may cause the GND of the electrical device 1 to become unstable. Therefore, if power is collected using an antenna or the like that is based on the GND of the electrical device 1, connecting a cable may cause the power harvest to become unstable. In contrast, in this embodiment, power is harvested from the heat sink 10, which is substantially isolated from the GND, so the impact of inserting a cable is small. This makes it possible to harvest power stably.

[0142] Second Embodiment A power generation device according to a second embodiment of the present technology will be described. In the following description, descriptions of parts similar to those of the power generation device 100 described in the above embodiment will be omitted or simplified.

[0143] In the above embodiment, a configuration has been described in which the heat sink 10 and the rectifier circuit 30 are electrically connected by the transmission line 21 that constitutes the transmission unit 20. In the present embodiment, a configuration will be described in which a transformer is provided in the transmission unit 20, and the heat sink 10 and the rectifier circuit 30 are connected via the transformer. By providing a transformer, it is possible to configure a power generation device that spans, for example, the primary circuit and secondary circuit of the electrical device 1.

[0144] [Configuration of power generating device having a transformer] Fig. 19 is a schematic diagram showing a configuration example of a power generating device according to a second embodiment. Fig. 20 is a block diagram showing a functional configuration example of the power generating device 200 shown in Fig. 19. As shown in Figs. 19 and 20 , the power generating device 200 has a heat sink 10, a transmission unit 20, a rectifier circuit 30, and a power storage unit 40, and harvests power from the heat sink 10 provided in the electrical device 1. Compared to the power generating device 100 described with reference to Fig. 1, for example, the power generating device 200 has a configuration in which a transformer 23 is added to the transmission unit 20.

[0145] In this embodiment, the circuit board 2 on which the semiconductor element 3 is provided is a primary power supply board that constitutes a primary circuit 61 of the electric device 1. Therefore, the semiconductor element 3 and the heat sink 10 that dissipates heat from the semiconductor element 3 are both provided in the primary circuit 61. In contrast, the rectifier circuit 30 and the power storage unit 40 are provided in a secondary circuit 62 of the electric device 1. In Figure 20, the left side of the thick dotted line is considered to be the primary circuit 61, and the right side is considered to be the secondary circuit 62.

[0146] The transmission unit 20 of the power generation device 200 connects the input terminal 31 of the rectifier circuit 30 and the heat sink 10 via a transformer 23. By using the transformer 23, it is possible to transmit AC power from the heat sink 10 to the rectifier circuit 30, but the two are electrically isolated from each other.

[0147] 19 , the transformer 23 is a transformer comprising a primary coil 25 and a secondary coil 26 that are magnetically coupled to each other. The transformer 23 has primary terminals 25a and 25b provided at both ends of the primary coil 25, and secondary terminals 26a and 26b provided at both ends of the secondary coil 26. For example, a common mode choke coil that can be mounted on a circuit board is used as the transformer 23. Note that the type and characteristics of the transformer 23 are not limited and are selected appropriately depending on, for example, the application of the power generation device 200, the amount of power harvested, etc.

[0148] In addition to the transformer 23, the transmission unit 20 also has a pair of primary-side transmission lines 27a and 27b and a pair of secondary-side transmission lines 28a and 28b. On the primary side of the power generation device 200, the first heat sink 10a is connected to a primary-side terminal 25a of the transformer 23 by the primary-side transmission line 27a. The second heat sink 10b is connected to a primary-side terminal 25b of the transformer 23 by the primary-side transmission line 27b. On the secondary side, the first input terminal 31a of the rectifier circuit 30 is connected to a secondary-side terminal 26a of the transformer 23 by the secondary-side transmission line 28a. The second input terminal 31b of the rectifier circuit 30 is connected to a secondary-side terminal 26b of the transformer 23 by the secondary-side transmission line 28b.

[0149] In this way, the first heat sink 10a and the second heat sink 10b are electrically connected via the primary coil 25. The first input terminal 31a and the second input terminal 31b of the rectifier circuit 30 are electrically connected via the secondary coil 26. Note that the first heat sink 10a and the second heat sink 10b are not short-circuited to the ground pattern 4 of the circuit board 2 (primary circuit 61), which serves as the GND of the electrical device 1, and therefore each function as an antenna that receives electromagnetic noise 16.

[0150] [Primary Side Circuit and Secondary Side Circuit] Generally, AC power is supplied directly from an external power source such as a commercial power source to the primary side circuit 61. For example, in Japan, 100V, 50 Hz or 60 Hz AC power is used as the commercial power source. In Europe, 220V-230V, 50 Hz AC power is supplied, and in North America, 115V-120V, 60 Hz AC power is supplied.

[0151] The primary circuit 61 converts this large amount of power to generate the power with the voltage required for the electrical device 1. Therefore, the semiconductor elements 3, such as switching transistors, provided in the primary circuit 61 generate electromagnetic noise 16 with very large energy. For this reason, it is the primary circuit 61 that can collect most of the electromagnetic noise 16 in the electrical device 1.

[0152] However, because the power supplied from a commercial power source or the like is very large, various safety regulations, such as UL standards, have been established to ensure safety. For example, the primary circuit 61 of the electrical device 1 must handle the power supplied from the commercial power source or the like before converting it into power for use by the electrical device 1. For this reason, safety regulations prohibit the primary circuit 61 and the secondary circuit 62 from sharing a GND or from being electrically connected to each other. In other words, within the electrical device 1, the primary circuit 61 and the secondary circuit 62 must be electrically isolated from each other. For this reason, the primary circuit 61 and the secondary circuit 62, including the GND, are connected via a transformer or the like.

[0153] 21 is a schematic diagram showing an example of the configuration of a power supply board including a primary circuit 61 and a secondary circuit 62. The power supply board 65 is a board that adjusts the power supplied from a predetermined power source 68 and generates power to be supplied to each part of the electrical device 1. The power supply board 65 includes the primary circuit 61 and the secondary circuit 62. Here, the primary circuit 61 and the secondary circuit 62 are provided on a single board, but are configured to be electrically separated from each other. The rough dotted line in the figure indicates the boundary between the primary circuit 61 and the secondary circuit 62 on the power supply board 65.

[0154] The primary circuit 61 is a circuit that receives power from a predetermined power source 68. The primary circuit 61 is provided with, for example, semiconductor elements 3 (such as switching transistors) that adjust the power of the power source 68 to be supplied to the secondary circuit 62. The power output from the semiconductor elements 3 of the primary circuit 61 is supplied to the secondary circuit 62 via a power supply transformer 66. The secondary circuit 62 is a circuit electrically isolated from the primary circuit 61. The secondary circuit 62, which constitutes the power supply board 65, is provided with semiconductor elements 3 (such as switching transistors) that further adjust the power supplied via the power supply transformer 66. The power output from each semiconductor element 3 of the secondary circuit 62 is output appropriately to a subsequent circuit via a connector portion 67.

[0155] 21 , for example, a power supply board 65 has three semiconductor elements 3 provided in a primary circuit 61, each provided with a heat sink 10. Three semiconductor elements 3 are also provided in a secondary circuit 62, each provided with a heat sink 10. Two power supply transformers 66 are provided at the boundary between the primary circuit 61 and the secondary circuit 62.

[0156] Here, two semiconductor elements 3 provided on the upper side of the primary circuit 61 and two semiconductor elements 3 provided on the upper side of the secondary circuit 62 are connected via a power supply transformer 66 shown on the upper side in the figure. Also, a semiconductor element 3 provided on the lower side of the primary circuit 61 and a semiconductor element 3 provided on the lower side of the secondary circuit 62 are connected via a power supply transformer 66 shown on the lower side in the figure. Also, the GND of the primary circuit 61 and the GND of the secondary circuit 62 are connected appropriately together with each semiconductor element 3 via the power supply transformer 66.

[0157] In this way, the power supply board 65 is provided with a large number of semiconductor elements 3 with heat sinks 10 in close contact therewith. Each of these heat sinks 10 can function as an antenna for receiving electromagnetic noise 16, but by using the heat sink 10 provided in the primary circuit 61, the amount of harvestable power can be significantly increased. However, due to the safety regulations mentioned above, the heat sink 10 provided in the primary circuit 61 cannot be electrically connected to the secondary circuit 62.

[0158] 19 and 20 according to this embodiment, the heat sink 10 provided in the primary circuit 61 is connected to the rectifier circuit 30 provided in the secondary circuit 62 via the transformer 23. In other words, the heat sink 10 and the rectifier circuit 30 are electrically separated. This makes it possible to configure the power generator 200 across the primary circuit 61 and the secondary circuit 62 without violating safety regulations.

[0159] For example, one of the heat sinks 10 provided in the primary circuit 61 is used as the first heat sink 10a shown in Fig. 19. Furthermore, another heat sink 10 provided in the primary circuit 61 is used as the second heat sink 10b shown in Fig. 19. In this case, the AC power of the electromagnetic noise 16 generated in the first heat sink 10a and the second heat sink 10b is transmitted to the rectifier circuit 30 provided in the secondary circuit 62 via the transformer 23 (primary coil 25 and secondary coil 26) of the power generation device 200.

[0160] With this configuration, it is possible to safely store the power harvested by the primary circuit 61 in the power storage element 55, such as a battery or a capacitor, in the secondary circuit 62. Furthermore, since the first heat sink 10a and the second heat sink 10b are provided in the primary circuit 61, the power of the generated electromagnetic noise 16 is large. This makes it possible to sufficiently increase the amount of power harvested compared to when power is harvested using the heat sink 10 of the secondary circuit 62, for example.

[0161] 19 does not include an additional filter or the like because the power generating device 200 can sufficiently suppress noise components that affect the electrical device 1 by harvesting electromagnetic noise 16 from the heat sink 10. However, the present invention is not limited to this, and a configuration for suppressing noise components may be provided as described below.

[0162] Fig. 22 is a schematic diagram showing another example of the configuration of the power generation device according to this embodiment. The power generation device 200a shown in Fig. 22 is an example in which the heat sink 10 is connected to only one input terminal 31 of the rectifier circuit 30. The power generation device 200a is applicable, for example, to a case in which only one heat sink 10 is provided in the primary side circuit 61.

[0163] The transmission unit 20 of the power generation device 200a includes a transformer 23, a pair of primary-side transmission lines 27a and 27b, a capacitor 22, and a pair of secondary-side transmission lines 28a and 28b. On the primary side of the power generation device 200a, the first heat sink 10a is connected to a primary-side terminal 25a of the transformer 23 via the primary-side transmission line 27a. One end of the capacitor 22 is connected to the GND (ground pattern 4) of the primary-side circuit 61, and the other end of the capacitor 22 is connected to a primary-side terminal 25b of the transformer 23 via the primary-side transmission line 27b. On the secondary side, a first input terminal 31a of a rectifier circuit 30 is connected to a secondary-side terminal 26a of the transformer 23 via the secondary-side transmission line 28a. A second input terminal 31b of the rectifier circuit 30 is connected to a secondary-side terminal 26b of the transformer 23 via the secondary-side transmission line 28b. In this manner, the transmission unit 20 of the power generation device 200 a has one of a pair of input terminals 31 connected to the heat sink 10 , and the other of the pair of input terminals 31 connected to the GND of the electric device 1 via the capacitor 22 .

[0164] For example, a method of discharging noise components to GND is used as an EMC measure to remove noise components in the high frequency band that are not the target of harvesting. If the primary terminal 25b is electrically connected to the ground pattern 4 without providing the capacitor 22, the heat sink 10 connected to the primary terminal 25a will be electrically connected to the ground pattern 4 via the primary coil 25 of the transformer 23. In this case, the DC component generated in the heat sink 10 may flow into the ground pattern 4, causing a leakage current.

[0165] To avoid such leakage current, in the power generation device 200a, a capacitor 22 is inserted between the primary terminal 25b of the transformer 23 and the ground pattern 4. The capacitor 22 separates the heat sink 10 and the ground pattern 4 in terms of DC, thereby avoiding leakage current. On the other hand, the capacitor 22 functions as a high-pass filter 50 that selectively passes noise components in a high frequency band that are not to be harvested. This allows the noise components that are not to be harvested to escape to GND. In this way, by using the configuration shown in FIG. 22, it is possible to achieve both the above-mentioned EMC measures and measures against leakage current, even when using the transformer 23.

[0166] Fig. 23 is a schematic diagram showing another example of the configuration of a power generation device according to this embodiment. The power generation device 200b shown in Fig. 23 is an example in which heat sinks 10 are connected to both input terminals 31 of a rectifier circuit 30, and includes a high-pass filter 50. The transmission unit 20 of the power generation device 200b connects different heat sinks 10 to the pair of input terminals 31 via a transformer 23. The high-pass filter 50 is provided on one of the heat sinks 10 connected to the pair of input terminals 31.

[0167] In the example shown in Figure 23, a high-pass filter 50 is provided between the second heat sink 10b on the left side of the figure and the ground pattern 4. The first heat sink 10a and the second heat sink 10b are electrically connected via the primary coil 25 of the transformer 23. Therefore, in a power generating device 200b having a transformer 23, noise countermeasures can be achieved by simply providing a high-pass filter 50 on one of the heat sinks 10. Therefore, in Figure 23, there is no need to provide a high-pass filter 50 on the first heat sink 10a.

[0168] Here, a high-pass filter 50 configured as a parallel circuit of a capacitor 52 and a resistor 53 is used. This high-pass filter 50 allows noise components that are not to be harvested to escape to the ground pattern 4, and the noise components can be consumed by the capacitor 52 and the resistor 53 (see FIG. 8, etc.). This makes it possible to implement EMC measures and measures against high-voltage ringing. Note that the type of high-pass filter 50 is not limited to this. For example, any filter that matches the frequency of the electromagnetic noise 16 to be harvested may be provided between one of the heat sinks 10 and the ground pattern 4.

[0169] [Example] Hereinafter, as an example to which the present technology is applied, a power generation operation using the power generation device 200b shown in Fig. 23 will be specifically described. A television was used as the electrical device 1 to which the power generation device 200b is applied. The power supply board 65 of the television is separated into a primary side circuit 61 and a secondary side circuit 62, as in the power supply board 65 shown in Fig. 21, for example. In the example, the power generation device 200b was configured using two heat sinks 10 provided on the primary side circuit 61 of the power supply board 65 of the television.

[0170] First, the television was turned on, and a 10 kΩ load resistor was inserted between the output terminals (first output terminal 32 a and second output terminal 32 b) of the rectifier circuit 30 in the configuration of the power generation device 200 b, and the voltage across the load resistor was measured. As a result, an output of approximately 4 V was obtained.

[0171] FIG. 24 is a graph showing the charging characteristics of a battery generated by a power generation device. FIG. 25 is a graph showing the discharging characteristics of a battery generated by a power generation device. FIGS. 24 and 25 show the measurement results of a charge / discharge experiment of a battery (storage element 55) generated by a power generation device 200b applied to a television. In this measurement, a battery with a capacity of 4 mAh and an output voltage of 2.3 V was used. Four common mode choke coils with different inductances were used as the transformers 23 of the power generation device 200b. The inductances of the transformers 23a, 23b, 23c, and 23d shown in FIGS. 24 and 25 are 190 mH, 159 mH, 100 mH, and 68 mH, respectively.

[0172] The graph shown in Figure 24 shows the charging characteristics when the battery receives power from the power generation device 200b using each of the transformers 23a to 23d while watching television. The vertical axis of the graph represents the battery voltage [V] during charging, and the horizontal axis represents the charging time [min]. The graph shown in Figure 24 shows that regardless of which transformer 23 is used, the battery voltage rises to about 2.4V within about 10 minutes of starting charging, and the battery is being charged. The battery was charged for 60 minutes.

[0173] The graph in Figure 25 shows the discharge characteristics when a battery charged using the method shown in Figure 24 is connected to a 1 kΩ load resistor and power is discharged. The vertical axis of the graph represents the battery voltage [V] during discharge, and the horizontal axis represents the discharge time [min]. Note that the battery is not being charged during discharge. For example, immediately after discharge begins, the output voltage is maintained at 2.3 V, but as the battery approaches empty, the voltage drops rapidly. The time until the voltage drops increases as the amount of power charged (charge amount) increases.

[0174] The graph shown in Figure 25 shows that the battery charged using transformer 23b had the greatest charge. The charge amounts of transformers 23d, 23c, and 23a decreased in this order. Thus, when using transformer 23b, which had the greatest charge amount, it was found that a maximum of 1.2 mAh could be charged with a voltage output of 2.3 V. This corresponds to 2.76 mWh of power. While the maximum charge amount was achieved with transformer 23b in this configuration, the inductance and type of transformer 23 can be selected appropriately depending on the condition of the heat sink 10, the amount of harvested power, and other factors.

[0175] In the above example, charging was performed while watching television, but power harvesting is also possible during standby. The amount of power harvested during standby was about one-tenth of the amount harvested while watching television, but with a 2.3V output, it was possible to harvest about 0.14mAh. This is equivalent to 0.32mWh of power.

[0176] Based on the above measurement results, the total power consumption for this configuration was calculated. For example, if the television viewing time is 12 hours and the standby time is 12 hours, it is possible to harvest and effectively utilize 48 kW of power per year. If the harvested power is used in the vicinity of the television, it could be used, for example, to charge the television's remote controller or to reduce the television's standby power consumption.

[0177] Here, we compare the measurement results of a solar panel intended for application to a television remote controller with those of the above-mentioned example. For example, the harvested power of a typical 3 cm x 2 cm solar panel is approximately 0.08 mWh when receiving indoor light of approximately 500 lux. In contrast, when using this technology, the harvested power even during standby mode of the television is 0.32 mWh, which shows that it is possible to harvest power approximately four times more efficiently than a solar panel.

[0178] Furthermore, if the operation buttons of a remote controller using BLE (Bluetooth Low Energy (registered trademark)) are used about 100 times a day, the power consumption will be about 5 μWh. From this perspective, it can be said that by using this technology, it is possible to fully harvest the power used by the remote controller. This makes it easy to build an energy harvesting system that can appropriately charge various peripheral devices.

[0179] Fig. 26 is a schematic diagram showing an application example of a power generation device. In Fig. 26, a power generation device 200c is used to charge a secondary battery of a remote controller 8 of a television 7. The power generation device 200c can be configured by combining, for example, the power generation device 200b shown in Fig. 23 with the power storage unit 40b shown in Fig. 17. In this case, the secondary battery of the remote controller 8 is used instead of the battery 56 of the power storage unit 40b. Of course, the configuration of the power generation device 200c is not limited to this, and other configurations may be used.

[0180] The diagram on the left side of Fig. 26A is a schematic diagram showing the overall shape of the remote controller 8, and the diagram on the right side is a schematic diagram showing the location of charging terminals provided on the remote controller 8. The remote controller 8 is provided with two systems of charging terminals: a USB charging terminal 17 and a TV charging terminal 18 connected to the power generation device 200c inside the television 7. The USB charging terminal 17 is a terminal for charging the secondary battery from the USB connector. On the other hand, the TV charging terminal 18 is connected to a terminal provided inside the television 7 to which power is supplied from the power generation device 200c.

[0181] For example, an insertion groove for receiving the remote controller 8 is created on the side of the television 7, and an output terminal of the power generation device 200c is provided in the insertion groove for connection to the TV charging terminal 18. The remote controller 8 is used by being inserted into and removed from the insertion groove as appropriate, as shown in FIG. 26B . The insertion groove also functions as a storage location for the remote controller 8.

[0182] 26C, when the remote controller 8 is stored in the insertion groove, the power generation device 200c is connected to the TV charging terminal 18, and charging of the secondary battery of the remote controller 8 begins. This allows the remote controller 8 to be charged using power harvested from the television 7 when not in use. At this time, a light-emitting element 19 such as an LED provided on the remote controller 8 may be configured to light up to indicate that the secondary battery is being charged.

[0183] The heat sink 10 of the primary circuit 61 of the power supply board 65 generates a large amount of electromagnetic noise 16, and so it is expected that power can be harvested efficiently. However, electrically connecting the heat sink 10 of the primary circuit 61 to the rectifier circuit 30 provided in the secondary circuit 62 would not satisfy safety regulations such as the UL standard. Due to these safety issues, it has been difficult to use the heat sink 10 of the power supply board 65, which generates a large amount of electromagnetic noise 16.

[0184] In the power generation devices 200, 200a, 200b, and 200c according to this embodiment, the heat sink 10 provided in the primary circuit 61 of the electric device 1 is connected via the transformer 23 to the rectifier circuit 30 provided in the secondary circuit 62. This makes it possible to electrically separate the heat sink 10 from the rectifier circuit 30, and therefore it becomes possible to use the heat sink 10 of the power supply board 65 that generates a large amount of electromagnetic noise 16 while still complying with safety regulations. This makes it possible to significantly improve the efficiency of power harvesting from the electric device 1.

[0185] Furthermore, in the above embodiment, the present technology has been mainly described as being applied to a television 7, but the present technology can be applied to any electrical appliance 1 as long as the product has a power supply board 65 separated into a primary circuit 61 and a secondary circuit 62. The present technology can be applied to household electrical appliances 1 such as refrigerators, washing machines, air conditioners, personal computers, audio systems, and vending machines. In this case, in addition to charging the remote controller 8, power may be supplied for updating data (firmware updates) performed while the electrical appliance 1 is in standby mode, downloading files, and the like.

[0186] Furthermore, this technology is not limited to household electrical appliances, but can also be applied to industrial equipment such as elevators, escalators, manufacturing robots, machine tools, and conveyance systems. Because industrial equipment generally consumes a lot of power, applying this technology makes it possible to supply even more power through energy harvesting.

[0187] <Third Embodiment> Fig. 27 is a schematic diagram showing a configuration example of a power generation device according to a third embodiment. In this embodiment, another method for harvesting power from the heat sink 10 of the primary circuit 61 of the electrical device 1 while satisfying safety regulations will be described. The power generation device 300 shown in Fig. 27 has a modified connection method between the transmission unit 20 and the heat sink 10 compared to the above embodiments.

[0188] In this embodiment, the circuit board 2 on which the semiconductor element 3 is provided is a primary power supply board that constitutes a primary circuit 61 of the electrical device 1. Therefore, the semiconductor element 3 and the heat sink 10 that dissipates heat from the semiconductor element 3 are both provided in the primary circuit 61. In contrast, the rectifier circuit 30 and the power storage unit 40 are provided in a secondary circuit 62 of the electrical device 1.

[0189] The transmission unit 20 of the power generation device 300 has an insulating sheet 70, a conductive sheet 71, and a transmission line 21. The insulating sheet 70 is an insulating sheet member arranged in contact with the heat sink 10. For example, an insulating resin film or a glass plate is used as the insulating sheet 70. The conductive sheet 71 is a conductive sheet member connected to the heat sink 10 via the insulating sheet 70 by capacitive coupling. For the conductive sheet 71, a metal sheet, a metallic braided material, or the like is used. The transmission line 21 is a wiring that connects the conductive sheet 71 and the input terminal 31 of the rectifier circuit 30. Therefore, the input terminal of the rectifier circuit 30 is connected to the conductive sheet 71.

[0190] Electromagnetic noise 16 generated on the heat sink 10 passes through the insulating sheet 70 and is received by the conductive sheet 71. As a result, electromagnetic noise 16 is generated on the conductive sheet 71. The heat sink 10 and the conductive sheet 71 are electrically separated by the insulating sheet 70 provided between them. This can be said to be a state in which the heat sink 10 and the conductive sheet 71 are connected by capacitive coupling.

[0191] Furthermore, the AC power of the electromagnetic noise 16 generated in the conductive sheet 71 is transmitted to the input terminal of the rectifier circuit 30 via the transmission line 21. In this way, the transmission unit 20 of the power generation device 300 is connected to the heat sink 10 by capacitive coupling and transmits the AC power of the electromagnetic noise generated in the heat sink 10. This makes it possible to harvest power from the heat sink 10 of the primary circuit 61 of the electrical device 1 while satisfying safety regulations.

[0192] 27 , a first insulating sheet 70a and a first conductive sheet 71a are attached in this order to a first heat sink 10a on the left side of the figure. The first conductive sheet 71a is connected to a first input terminal 31a of the rectifier circuit 30 via a first transmission line 21a. Similarly, a second insulating sheet 70b and a second conductive sheet 71b are attached in this order to a second heat sink 10b on the right side of the figure. The second conductive sheet 71b is connected to a second input terminal 31b of the rectifier circuit 30 via a second transmission line 21b.

[0193] With this configuration, it is possible to harvest power from both the first heat sink 10a and the second heat sink 10b provided in the primary circuit 61. In this way, by using the insulating sheet 70 and the conductive sheet 71, it is possible to easily configure the power generating device 300 that harvests power from the heat sink 10 of the primary circuit 61 without incorporating a transformer.

[0194] Furthermore, by using this method, it is possible to combine not only the heat sink 10 of the primary circuit 61 but also the heat sink 10 of the secondary circuit 62. Therefore, even if, for example, the first heat sink 10a is provided in the primary circuit 61 and the second heat sink 10b is provided in the secondary circuit 62, it is possible to harvest power from each heat sink 10.

[0195] [Power Harvesting from Heat Sinks] The following describes the measurement results when power was actually harvested from the heat sinks 10. In this measurement, power was harvested from the heat sinks 10 provided in a television as an example of electrical equipment 1. The heat sinks 10 targeted were five heat sinks 10 provided in the primary circuit 61 of the television's power supply board. Here, the heat sinks 10 (HS) targeted for measurement are referred to as HS1, HS2, HS3, HS4, and HS5.

[0196] 28 is a graph showing the noise characteristics of the heat sink 10 provided in the primary-side circuit 61. Fig. 28 shows the frequency distribution of electromagnetic noise generated in HS1 to HS5. The horizontal axis of each graph represents frequency [kHz], and the vertical axis represents the noise power level [dBm] at each frequency. The thick horizontal line in each graph represents the -10 dBm line.

[0197] For example, in HS1, HS2, and HS3, the power level was −10 dBm or less at frequencies above 10 kHz. On the other hand, in HS4 and HS5, peaks exceeding −10 dBm were observed at frequencies above 10 kHz, indicating that noise with relatively high energy was being generated.

[0198] 29 is a schematic diagram showing the circuit configuration of a power generating device 210 using a heat sink 10 of a primary side circuit 61. The power generating device 210 is composed of a transformer 23, a rectifier circuit 30, and a heat sink 10 of a primary side circuit 61. A battery 59 is connected downstream of the power generating device 210.

[0199] 29 , one primary-side terminal 25a of the transformer 23 is connected to a heat sink 10 (one of HS1 to HS5) of the primary-side circuit 61, and the other primary-side terminal 25b is connected to a primary-side GND 77 provided in the primary-side circuit 61. One secondary-side terminal 26a of the transformer 23 is connected to a first input terminal 31a of the rectifier circuit 30, and the other secondary-side terminal 26b is connected to a second input terminal 31b of the rectifier circuit 30. The first output terminal 32a of the rectifier circuit 30 is connected to the positive electrode of the battery 59, and the second output terminal 32b is connected to the negative electrode of the battery 59.

[0200] The above-mentioned primary GND 77 is also called the power supply GND or Primary GND (PG) on the power supply board, and is configured, for example, by a conductor such as a ground pattern provided in the primary circuit 61 of the electrical device 1. The primary GND 77 is used in a state where it is electrically floating from the earth GND 6, and supplies a reference potential to the electrical device 1 (here, a television). The heat sink 10 provided in the primary circuit 61 is attached to a switching element or the like in a state where it is floating from the primary GND 77. Therefore, the heat sink 10 is also a conductor that is electrically floating from the earth GND 6.

[0201] In the power generation device 210, the transformer 23 and the primary side GND 77 are directly connected, but for example, a capacitor may be provided between the transformer 23 and the primary side GND 77 to avoid leakage current (see Figure 22, etc.).

[0202] To measure the power harvest from the heat sinks 10 (HS1 to HS5) of the primary circuit 61, the battery 59 was first charged for a certain period of time using the circuit configuration shown in Figure 29, and its discharge characteristics were examined. Specifically, the discharged battery 59 was connected to the power generation device 210 and charged for one hour. The charged battery 59 was then connected to a 1 kΩ resistor and discharged, and the change in battery voltage was measured.

[0203] Figure 30 is a graph showing the discharge characteristics of battery 59 charged using power generation device 210 shown in Figure 29. Graphs G1 to G5 shown in Figure 30 correspond to the discharge characteristics of HS1 to HS5, respectively. The horizontal axis of the graph represents time [h], and the vertical axis represents the voltage [V] applied to the resistance element. In this discharge characteristic graph, the longer the time it takes for the voltage to reach 0 V, the greater the amount of power charged in battery 59, i.e., the greater the amount of power harvested from heat sink 10.

[0204] In this measurement, when the battery 59 was charged with HS4, it took the longest time for the voltage to reach 0 V, and it was confirmed that a relatively large amount of power (37.3 mWh) was harvested from HS4. Note that with the other heat sinks 10, the voltage reached 0 V earlier than with HS4. For example, the amount of power harvested from HS1 was 0.95 mWh, the amount of power harvested from HS2 was 0.17 mWh, the amount of power harvested from HS3 was 0.39 mWh, and the amount of power harvested from HS5 was 0.67 mWh.

[0205] As explained with reference to Fig. 28, among the heat sinks 10 other than HS4, HS5 generates noise with a relatively large amount of energy, similar to HS4. However, in the configuration shown in Fig. 29, the amount of power harvested from HS5 is about the same as that of HS1, HS2, and HS3, which have lower noise levels. In this regard, the inventors suspected that the reason for the small amount of power harvested from HS5 may be that impedance matching was not achieved, and improved the circuit configuration.

[0206] FIG. 31 is a schematic diagram showing the circuit configuration of a power generation device 211 with impedance matching. The power generation device 211 is obtained by adding an inductor element 130 to the power generation device 210 shown in FIG. 29. Specifically, the inductor element 130 is connected between the primary terminals 25a and 25b of the transformer 23 (between the heat sink 10 and the primary GND 77). The inductance of the inductor element 130 is set so as to achieve impedance matching between the heat sink 10 to be harvested and the downstream circuit including the transformer 23. Here, an inductor element 130 with an inductance of 4 mH was used for HS5.

[0207] Fig. 32 is a graph showing the discharge characteristics of battery 59 charged using power generation device 211 shown in Fig. 31. Fig. 32 also shows a graph (G6) of the discharge characteristics of battery 59 charged by power generation device 211 that harvests power from HS5. For comparison, Fig. 32 also shows a graph G5 of the discharge characteristics when power from HS5 is charged using power generation device 210 shown in Fig. 29, and a graph G4 of the discharge characteristics when power from HS4 is charged using power generation device 210.

[0208] For example, compared to the discharge characteristics (G5) when charging without the inductor element 130, the graph of G6 shows that the time until the voltage reaches zero is significantly increased, becoming similar to the discharge characteristics (G4) of HS4. In this case, the amount of power harvested from HS5 is 37.8 mWh, confirming that a large amount of power can be harvested at the same level as HS4. In this way, by achieving impedance matching using the inductor element 130 or the like, it is possible to increase the amount of power that can be harvested.

[0209] From the results so far, it was found that HS4 and HS5 can harvest large amounts of power. Based on this, the inventors thought that using two heat sinks 10 (HS4 and HS5) would make it possible to further increase the amount of power harvested, and further improved the circuit configuration.

[0210] 33 is a schematic diagram showing the circuit configuration of a power generating device 212 that harvests power from two heat sinks 10. The power generating device 212 is a device that harvests power from both heat sinks 10 (HS4 and HS5) while achieving the required impedance matching for the two heat sinks 10.

[0211] 33, in the power generation device 212, one heat sink 10 (HS4 in this example) is connected to one primary terminal 25a of the transformer 23, and another heat sink 10 (HS5 in this example) is connected to the other primary terminal 25b. Furthermore, in the power generation device 212, the primary terminal 25b to which HS5 is connected is connected to the primary GND 77 via the inductor element 130. With this configuration, it is possible to achieve impedance matching for HS5.

[0212] Fig. 34 is a graph showing the discharge characteristics of battery 59 charged using power generation device 212 shown in Fig. 33. Fig. 34 also shows a graph (G7) of the discharge characteristics of battery 59 charged by power generation device 212 connected to HS4 and HS5. For comparison, Fig. 34 also shows a graph G4 of the discharge characteristics when power is charged from HS4 using power generation device 210 shown in Fig. 29, and a graph G6 of the discharge characteristics when power is charged from HS5 using power generation device 211 shown in Fig. 31.

[0213] For example, looking at the graph for G7, we can see that the power harvest is even greater than that of G4 and G6, which had large power harvests. This is thought to be because power was efficiently harvested from the two heat sinks 10 (HS4 and HS5), and the amount of power harvested from HS4 and HS5 was 60.7 mWh.

[0214] In this way, by achieving impedance matching with the heat sink 10 that is the target of power harvesting, it is possible to significantly increase the amount of power that can be harvested. Furthermore, even when two heat sinks 10 are used, impedance matching makes it possible to efficiently harvest power from both heat sinks 10. This makes it possible to harvest power by arbitrarily combining heat sinks 10 with high noise levels, for example, and significantly improves the harvesting efficiency.

[0215] Other Embodiments The present technology is not limited to the above-described embodiments, and various other embodiments can be realized.

[0216] In the above embodiment, the power generating device is described as having at least one heat sink. However, the power generating device does not necessarily have to have a heat sink. For example, an attachment-type power generating device may be configured to be connected to a heat sink provided on an existing electrical device. Note that the heat sink used is configured to have a potential different from the GND of the electrical device.

[0217] Such an attachment-type power generator is configured to include, for example, a cable (transmission unit) for connecting to a heat sink and a rectifier circuit. Of course, a storage unit or the like connected to the rear of the rectifier circuit may be provided as appropriate. This makes it possible to efficiently harvest power from various electrical devices. Furthermore, by combining the power generator with a sensor or the like, it becomes possible to easily configure a monitoring device or the like that detects the status of electrical devices.

[0218] As described above, this technology realizes energy harvesting by connecting a heat sink of an electrical device to a rectifier circuit via a transmission unit. This connection method includes connecting a transmission unit, which transmits AC power of electromagnetic noise generated on at least one heat sink that has a different potential from the GND of the electrical device, directly or by capacitive coupling, to the heat sink, and connecting the transmission unit to a rectifier circuit that rectifies the AC power and outputs DC power. This connection method enables efficient power harvesting from the electrical device.

[0219] This technology can be applied to various metal objects that are attached to electrical equipment and are subject to electromagnetic noise. Specifically, as long as the metal object is attached to electrical equipment, receives electromagnetic noise from a noise source, and is floating above the ground, it is possible to efficiently harvest the power of the electromagnetic noise from the metal object, even if it is a metal object other than the heat sink described above.

[0220] Here, the metal body provided in the electrical equipment is, for example, a member made of a metal material that constitutes the electrical equipment, or a product metal part included in the electrical equipment. The heat sink described in the above embodiment is an example of a metal body provided in the electrical equipment. For example, the description of the heat sink in the above embodiment can be appropriately interpreted as a description of the metal body. Below, a power generation device using a metal body provided in the electrical equipment will be described.

[0221] 35 is a schematic diagram showing an example of the configuration of a power generation device using metal bodies of electrical devices. The power generation device 400 is a device that harvests, as power, electromagnetic noise received by each metal body 76 provided on two electrical devices 1. For example, it is possible to harvest power from the metal bodies 76 provided on two electrical devices 1 that are not grounded. This is a configuration that harvests power from two different noise sources.

[0222] First, the electric device 1 to which the power generation device 400 is connected will be described. The electric device 1 has a power cable 74, an internal circuit 75, and a metal body 76. The power cable 74 is connected to an external power line (AC power supply). In this example, a two-terminal type cable that does not have an earth wire for grounding to the earth GND 6 is used as the power cable 74.

[0223] The internal circuit 75 is a variety of circuits for operating the electrical device 1, and is connected to a power cable 74. The internal circuit 75 includes semiconductor elements such as switching transistors and control ICs, and therefore serves as a noise source in the electrical device 1. Of course, noise sources in the electrical device 1 are not limited to the internal circuit 75; other components (such as power wiring) may also generate electromagnetic noise, and all of these elements may serve as noise sources.

[0224] The metal body 76 is a metal member provided on the electric device 1. In this embodiment, an electric light is used as the electric device 1. In this case, for example, metal members constituting the electric light, such as a shade, an arm, and a housing, serve as the metal body 76 provided on the electric light. Furthermore, a ground pattern or the like that serves as the GND of the electric device 1 is provided on the internal circuit 75. Such a ground pattern is also the metal body 76 of the electric device 1. Note that structural components such as a housing and metal films on the circuit, such as ground patterns, may be connected inside the electric device, or may be used in an electrically independent state.

[0225] 35 illustrates an example in which metal bodies 76 provided on two electric devices 1 are connected to a rectifier circuit 30 via a transmission unit 20. Hereinafter, the light (electrical device 1) on the left side of the drawing will be referred to as a first light 80a, and the light (electrical device 1) on the right side of the drawing will be referred to as a second light 80b. The metal body 76 provided on the first light 80a will be referred to as a first metal body 76a, and the metal body 76 provided on the second light 80b will be referred to as a second metal body 76b. In FIG. 35, the first light 80a corresponds to the first electric device, and the second light 80b corresponds to the second electric device.

[0226] The number of electric devices 1 (metal bodies 76) used in the power generation device 400 is not limited. For example, the power generation device 400 may be configured for a single electric device 1. Furthermore, it is sufficient that at least one metal body 76 floating from the GND 6 of the earth is connected to the rectifier circuit 30. For example, it is also possible to configure two metal bodies 76 connected to the rectifier circuit 30 such that one metal body 76 floats from the GND 6 of the earth and the other metal body 76 is connected to the GND 6 of the earth.

[0227] Next, the power generation device 400 will be described. The power generation device 400 is configured as an externally connected device that is used by connecting to, for example, existing electrical devices 1 (first electric lamp 80a and second electric lamp 80b). As shown in Fig. 35 , the power generation device 400 has a transmission unit 20 and a rectifier circuit 30.

[0228] The transmission unit 20 is provided in the electrical device 1 and is directly connected to a metal body 76 having a different potential from the ground GND 6, and transmits AC power of electromagnetic noise generated in the metal body 76. Here, the metal body 76 having a different potential from the ground GND 6 refers to, for example, a metal body 76 that is floating above the ground GND 6. In the example shown in FIG. 35 , both the first metal body 76a and the second metal body 76b have a different potential from the ground GND 6. For example, if the electrical device 1 is not grounded, the ground pattern will be the metal body 76 floating above the ground GND 6. Furthermore, if the metal housing of the electrical device 1 is not connected to the ground GND 6, it will also be the metal body 76 floating above the ground GND 6.

[0229] Note that if the ground pattern and the metal housing are connected, when the electric device 1 is grounded and the ground pattern is earthed, the metal housing is also connected to the earth GND 6. On the other hand, if the ground pattern and the metal housing are not connected, even if the electric device 1 is grounded, the metal housing remains floating from the earth GND 6. Thus, in the present disclosure, the metal body 76 provided in the electric device 1 and having a potential different from the earth GND 6 may be any metal body 76 that is not electrically connected to the earth GND 6.

[0230] These metal bodies 76 are connected to a pair of input terminals 31 provided in the rectifier circuit 30 via the transmission unit 20. Specifically, the transmission unit 20 connects the first metal body 76a to one of the pair of input terminals 31 (first input terminal 31a) and connects the second metal body 76b to the other of the pair of input terminals 31 (second input terminal 31b).

[0231] 35 , the transmission unit 20 has two transmission lines 21 (a first transmission line 21a and a second transmission line 21b). The first transmission line 21a is a connection cable that connects the first metal body 76a to the first input terminal 31a. The second transmission line 21b is a connection cable that connects the second metal body 76b to the second input terminal 31b. One end of the first transmission line 21a and the second transmission line 21b is electrically connected directly to the first metal body 76a and the second metal body 76b that are the connection targets.

[0232] There is no limitation on the method for directly connecting the transmission line 21 and the metal body 76. For example, a screw terminal, a crimp terminal, a metal clip, a magnetic terminal, or the like may be provided at one end of the transmission line 21 (connection cable), and the transmission line 21 may be electrically connected to an exposed portion of the metal body 76 using these. Alternatively, the connection may be made using a pin or a socket, or by soldering or welding.

[0233] Note that the configuration is not limited to a direct connection between the transmission line 21 and the metal body 76, and the transmission line 21 may be connected to the metal body 76 by capacitive coupling, for example. For example, a metal pad may be provided at one end of the transmission line 21, and the metal pad may be attached to the metal body 76. In this case, the metal pad and the metal body 76 do not need to be electrically connected. As a method for capacitive coupling, for example, the technique using the insulating sheet 70 or conductive sheet 71 described with reference to FIG. 27 can also be applied.

[0234] The rectifier circuit 30 rectifies the AC power transmitted by the transmission unit 20 and outputs DC power. The rectifier circuit 30 has a pair of input terminals 31 (a first input terminal 31a and a second input terminal 31b) to which the metal body 76 is connected via the transmission unit 20, and a pair of output terminals 32 (a first output terminal 32a and a second output terminal 32b) that output DC power. As the rectifier circuit 30, for example, the one described with reference to FIGS. 13 and 14 can be used.

[0235] As described above, the first lamp 80a and the second lamp 80b to which the power generation device 400 is connected are connected to an AC power source to obtain power, but are not connected to the earth GND 6. Therefore, the first metal body 76a and the second metal body 76b constituting the first lamp 80a and the second lamp 80b are floating from the earth GND 6. In this state, the first metal body 76a and the second metal body 76b function as antennas that receive electromagnetic noise.

[0236] Furthermore, the first lamp 80a and the second lamp 80b each include a noise source (e.g., an internal circuit 75) that generates electromagnetic noise. Therefore, the first metal body 76a and the second metal body 76b receive electromagnetic noise from the electrical device 1 (the first lamp 80a and the second lamp 80b) that they respectively constitute. Therefore, when the first metal body 76a and the second metal body 76b are connected to the input terminals 31 of the rectifier circuit 30, the energy of the electromagnetic noise received by the first metal body 76a and the second metal body 76b is converted into DC power by the rectifier circuit 30. In this way, by having the metal body 76 provided in each electrical device 1 function as an antenna, it is possible to efficiently harvest the electromagnetic noise generated by each electrical device 1.

[0237] Fig. 36 is a schematic diagram showing an example of the configuration of a power generation device using a signal cable. In the power generation device 500 shown in Fig. 36, a signal cable 85 is used to connect two electrical devices 1 together, and the metal body 76 is connected to the rectifier circuit 30. Here, the signal cable 85 is a cable for transmitting data signals such as analog signals and digital signals.

[0238] In the example shown in Fig. 36, a game console 81 and a television 82 are used as the electrical appliances 1 to be harvested for power. Furthermore, a video transmission cable (e.g., an HDMI (registered trademark) cable, a DisplayPort (registered trademark) cable, a DVI cable, an RGB cable, or the like) that transmits a video signal from the game console 81 to the television 82 is used as the signal cable 85. In Fig. 36, the game console 81 and the television 82 correspond to the first electrical appliance and the second electrical appliance.

[0239] The game console 81 and the television 82 are connected to an AC power source but are not grounded to the earth's GND 6. In this case, the metal bodies 76 (housings, ground patterns, etc.) provided on the game console 81 and the television 82 are basically floating from the earth's GND 6. Hereinafter, the metal body 76 (housing, etc.) provided on the game console 81 will be referred to as a first metal body 76a, and the metal body 76 (housing, etc.) provided on the television 82 will be referred to as a second metal body 76b.

[0240] 36 , in the power generation device 500, a first transmission line 21a connects a first metal body 76a provided in a game console 81 to a first input terminal 31a of a rectifier circuit 30. A second transmission line 21b connects a second metal body 76b provided in a television 82 to a second input terminal 31b of the rectifier circuit 30.

[0241] Here, the first transmission line 21a and the second transmission line 21b are wirings that function as the transmission unit 20 of the power generation device 500, and these wirings are configured using the signal cable 85. In this way, the transmission unit 20 connects the first metal body 76a provided on the game console 81 and the second metal body 76b provided on the television 82 to a pair of input terminals 31 of the rectifier circuit 30 via the signal cable 85 (video transmission cable) that connects the game console 81 and the television 82.

[0242] The power generation device 500 that uses the signal cable 85 is provided with, for example, two connection terminals to which the signal cable 85 is connected, and internal wiring that connects each connection terminal to a pair of input terminals 31 of the rectifier circuit 30. In this case, the connection terminals and internal wiring function as the transmission unit 20 provided in the power generation device 500. Note that the signal cable 85 connected to the power generation device 500 can also be considered as part of the transmission unit 20.

[0243] The signal cable 85 generally includes a signal line 86 (dotted line in the figure) for transmitting a signal, as well as a GND line 87 for connecting to the GND (ground pattern) of the electrical device 1. The power generation device 500 uses this GND line 87 as a transmission line 21 (transmission unit 20) for connecting the metal body 76 and the rectifier circuit 30.

[0244] That is, in the power generation device 500, the first metal body 76a and the second metal body 76b are connected to a pair of input terminals 31 via the GND line 87 of the video transmission cable, which is the signal cable 85. Therefore, the ground patterns provided on each of the game console 81 and the television 82 function as the first metal body 76a and the second metal body 76b. This can also be said to be a configuration in which the power generation device 500 is inserted between the GNDs of two electrical devices 1 (the game console 81 and the television 82) whose ground patterns are not connected to the earth GND 6.

[0245] For example, in a signal cable such as an HDMI (registered trademark) cable, differential transmission of video signals and the like is performed in the signal line. Therefore, even if the GND line 87 is interrupted in the middle, that is, even if the power generation device 500 is connected in the middle of the GND line 87, signal transmission can be performed properly. In this way, it is also possible to introduce a power harvesting function between (in the middle of) the GND line 87 of the signal cable 85. This makes it possible to easily harvest power using various signal cables 85.

[0246] The game console 81 and the television 82 may use a three-terminal power cable 74 including a ground terminal. If one of the electrical devices 1 is grounded to the earth GND 6, the amount of power harvested from the grounded electrical device 1 may decrease, but power can be harvested without any problems from the other electrical device 1 that is not grounded. In this way, power can be harvested even if one of the electrical devices 1 is grounded.

[0247] Fig. 37 is a schematic diagram showing another example of the configuration of a power generation device using a signal cable. The power generation device 600 shown in Fig. 37 uses a communication cable (LAN cable) as the signal cable 85 to connect the metal body 76 of each electrical device 1 to the rectifier circuit 30. In this example, a router 83 and a television 82 are used as the electrical devices 1 to be harvested for power. The router 83 and the television 82 correspond to the first electrical device and the second electrical device.

[0248] The power generation device 600 has a configuration in which the video transmission cable in Fig. 36 is replaced with a communication cable. Hereinafter, the metal body 76 (housing, etc.) provided on the router 83 will be referred to as a first metal body 76a, and the metal body 76 (housing, etc.) provided on the television 82 will be referred to as a second metal body 76b. Because the router 83 and the television 82 are not grounded to the earth GND 6, the first metal body 76a and the second metal body 76b are metal bodies 76 floating above the earth GND 6.

[0249] Even when a LAN cable is used, the GND line 87 can be used. That is, in the power generation device 600, the first metal body 76a and the second metal body 76b are connected to the pair of input terminals 31 via the GND line 87 of the LAN cable, which is a signal cable. Therefore, the ground patterns provided on the router 83 and the television 82 function as the first metal body 76a and the second metal body 76b. In this way, it is also possible to introduce a power harvesting function between (along the way of) the GND line 87 of the LAN cable.

[0250] It is considered that the GND line 87 of the original LAN cable 88 connected to the router 83 is connected to the earth GND 6 on the upstream side. For this reason, the GND line 87 of the LAN cable (signal cable 85) on the television side may not be connected to the GND line 87 of the LAN cable 88. This makes it possible to efficiently harvest power from the first metal body 76a of the router 83 as well.

[0251] The power generation devices 500 and 600 shown in Figures 36 and 37 are devices that are used by being inserted into the GND line 87 of a signal cable 85 that connects two electrical devices 1. Such power generation devices may be configured as a cable unit that includes the signal cable 85. The cable unit is, for example, a unit in which the power generation device and the signal cable 85 are integrated, and circuits such as the rectifier circuit 30 that configure the power generation device are built into the signal cable 85. This makes it possible to realize a signal cable 85 with a power harvesting function.

[0252] The power generation device may also be configured as a relay unit that relays the signal cable 85. The relay unit is provided with, for example, two connection terminals for the signal cable 85, and the GND line of each connection terminal is connected to the rectifier circuit 30. Therefore, two electric devices 1 are each connected to the power generation device, which is the relay unit, via the signal cable 85. This makes it possible to harvest power from any electric device 1 using a commonly used signal cable 85.

[0253] The power generation device may also be configured as a connector unit to which a signal cable 85 is connected in the electric device 1. The connector unit is a unit that is pre-installed in one of the electric devices 1 and to which an end of the signal cable 85 is connected. In this case, the electric device 1 equipped with the power generation device can harvest and use not only the power it generates itself but also the power generated by other electric devices 1 connected from the outside. In addition, the configuration of the power generation device using the signal cable 85 is not limited.

[0254] Fig. 38 is a schematic diagram showing another example of the configuration of a power generation device using a signal cable. The power generation device 700 shown in Fig. 38 is configured as an internal unit of the electrical device 1, and is connected to multiple electrical devices 1 via signal cables 85. Here, an example will be described in which the power generation device 700 is provided in a router 83 to which multiple electrical devices 1 are connected via LAN cables.

[0255] 38 , a game console 81 is connected to a router 83 via a first signal cable 85a (first LAN cable), and a television 82 is connected to the router 83 via a second signal cable 85b (second LAN cable). In this example, the game console 81 and the television 82 correspond to the first and second electrical devices. The router 83 corresponds to the third electrical device.

[0256] The first signal cable 85a and the second signal cable 85b function as the transmission unit 20 of the power generation device 700. That is, in the power generation device 700, the first metal body 76a provided on the game console 81 is connected to one of the pair of input terminals 31 (first input terminal 31a) via the first signal cable 85a, and the second metal body 76b provided on the television 82 is connected to the other of the pair of input terminals 31 (second input terminal 31b) via the second signal cable 85b.

[0257] 36 is configured as a connector unit inside the router 83. This allows the router 83 to use the power harvested by the power generation device 700 from the game console 81 and the television 82.

[0258] It is considered that the GND line 87 of the original LAN cable 88 connected to the router 83 is connected to the earth's GND 6. For this reason, for example, the GND line 87 of the LAN cables (first signal cable 85a and second signal cable 85b) on the game console 81 and television 82 side is configured not to be connected to the GND line 87 of the LAN cable 88. This makes it possible to efficiently harvest power from the game console 81 and television 82.

[0259] Fig. 39 is a schematic diagram showing an example of the configuration of a power generation device in which an inductor element is provided between transmission lines. The power generation device 800 shown in Fig. 39 has a configuration in which an inductor element 110 is added to the power generation device 500 shown in Fig. 36. In this example, a game console 81 and a television 82 correspond to the first and second electrical devices. The power generation device 800 is inserted midway through a signal cable 85 (video transmission cable) connecting the game console 81 and the television 82.

[0260] The transmission unit 20 of the power generation device 800 has a first transmission line 21a, a second transmission line 21b, and an inductor element 110. The first transmission line 21a is connected to a first metal body 76a provided in the game console 81. The second transmission line 21b is connected to a second metal body 76 provided in the television 82. Here, the first transmission line 21a and the second transmission line 21b are formed by a GND line 87 of a signal cable 85.

[0261] The inductor element 110 is provided between the first transmission line 21 a and the second transmission line 21 b. The inductor element 110 is, for example, an element such as a coil. In the example shown in Fig. 39, a single coil is used as the inductor element 110. In this manner, the inductor element 110 may be inserted between each transmission line 21 connecting two electric devices 1 to the rectifier circuit 30.

[0262] This allows the GND (ground pattern) of each electrical device 1 to be electrically connected, enabling stable signal transmission. Also, by appropriately setting the inductance of the inductor element 110, it is possible to achieve impedance matching with the rectifier circuit 30. This allows AC power (electromagnetic noise power) transmitted via the first transmission line 21a and the second transmission line 21b to be efficiently input to the rectifier circuit 30, thereby improving power harvesting efficiency.

[0263] As described with reference to Fig. 19 and other figures, a configuration is also possible in which a transformer is used to connect the electrical device 1 and the rectifier circuit 30. In this case, the transformer functions as an inductor element. The following description also applies to the case in which a transformer is used.

[0264] A parameter that represents the inductance characteristics of the inductor element 110 is called a Q value. The Q value is calculated according to the following formula: Q=2πfL / R (1) In formula (1), f is the frequency of a signal passing through the inductor element 110, L is the inductance, and R is the resistance component of the inductor element 110 that corresponds to the frequency f.

[0265] For example, if the Q value is low in a desired frequency band, this means that the resistance component R is large in that frequency band. Here, the desired frequency band is, for example, a frequency band in which electromagnetic noise occurs that is to be harvested by the power generation device 800. Therefore, if the Q value is low in the desired frequency band, the power of the electromagnetic noise is consumed by the resistance component R in the inductor element 110, that is, the power of the electromagnetic noise is converted into heat, and the amount of power harvested via the rectifier circuit 30 is thought to decrease.

[0266] Therefore, the present inventors conducted an experiment to investigate the relationship between the Q value of the inductor element 110 and the output of the rectifier circuit 30. FIG. 40 is a schematic diagram showing an example of a measurement of the power harvest yield depending on the Q value of the inductor element. FIG. 41 is a table showing an example of the frequency characteristics of the Q value of an inductor. In this experiment, a common mode choke coil was used as an example of the inductor element 110. A common mode choke coil is used, for example, as a filter to reduce common mode noise. Here, the common mode choke coil is referred to as a CMF (Common Mode Filter) 112. Furthermore, although this example is of a common mode choke, a transformer may also be used.

[0267] 40 , the CMF 112 has a primary coil 113 and a secondary coil 114. The primary coil 113 has primary terminals 113a and 113b, and the secondary coil 114 has secondary terminals 114a and 114b. The primary terminal 113a is in phase with the secondary terminal 114a, and the primary terminal 113b is in phase with the secondary terminal 114b.

[0268] In the experiment, the metal body 76 of the electrical device 1, which was not grounded to the earth GND 6, was connected to the primary side terminal 113a, and the primary side terminal 113b was grounded to the earth GND 6. The secondary side terminals 114a and 114b were connected to the first input terminal 31a and the second input terminal 31b of the rectifier circuit 30, respectively.

[0269] FIG. 41 shows the inductance [mH], Q factor, and resistance component R [Ω] for two types of CMF 112 (Sample 1 and Sample 2) used in the experiment at 100 Hz, 1 kHz, 10 kHz, and 100 kHz. Samples with similar inductance values ​​were used here. Sample 1 has a higher Q factor at each frequency than Sample 2. For example, at 100 kHz, the Q factor of Sample 1 is 17.8, and the Q factor of Sample 2 is 3.3.

[0270] Fig. 42 shows the measurement results of the power harvest yield depending on the Q value of the inductor element. Fig. 42A and Fig. 42B are graphs plotting the current value output from the rectifier circuit 30 when two types of CMF 112 (Sample 1 and Sample 2) are used as the inductor element 110. The vertical axis of each graph represents the current value [µA], and the horizontal axis represents time.

[0271] Here, a resistive load was connected between the first output terminal 32 a and the second output terminal 32 b of the rectifier circuit 30, and the current flowing through the resistive load was detected. The resistance value of the resistive load was switched in this order at regular time intervals: 100 Ω, 1 kΩ, 10 kΩ, 100 kΩ, and 1 MΩ.

[0272] The amount of current obtained when Sample 1 was used was higher than when Sample 2 was used at all resistance values. For example, when the resistance values ​​were 100Ω, 1 kΩ, and 10 kΩ, more than twice the amount of current was obtained. This is thought to be because the Q value of Sample 1 was higher than the Q value of Sample 2 in the frequency band where electromagnetic noise occurs. In this way, it was found that a higher Q value of the inductor element 110 increases the power harvesting efficiency.

[0273] For example, the Q value of Sample 1 was 10 or more in the frequency band of 100 kHz or less, where the strength of electromagnetic noise generally received by the metal body 76 of the electrical device 1 is relatively high. In light of this, it is preferable to set the Q value of the inductor element 110 in the frequency band to be harvested to 10 or more. This makes it possible for the power generating device 800 including the inductor element 110 to harvest power at a high efficiency.

[0274] If the Q value is too high, the peak width appearing in the frequency characteristics of the Q value will be narrow. In other words, if the Q value is locally high, the Q value will decrease in frequency bands outside the peak. This may limit the frequency band of electromagnetic noise that can be harvested. Therefore, it is preferable to set the Q value of the inductor element 110 appropriately in a range of 10 or more, so that the frequency of the electromagnetic noise is not significantly limited. In addition, the lower and upper limits of the Q value of the inductor element 110 are not limited, and may be set appropriately depending on the frequency band of the electromagnetic noise to be targeted, the system to which the power generation device 800 is applied, etc.

[0275] In the above embodiment, the power generation device has been described as using a signal cable 85 to transmit information mainly between the electrical devices 1. However, the present invention is not limited to this, and it is also possible to configure the power generation device by using, for example, a power cable to transmit power between devices.

[0276] 43 is a schematic diagram showing an example of the configuration of a power generation device using a power cable. The power generation device 850 is connected to a power cable 140 that connects a servo amplifier 135 and a motor 136. The servo amplifier 135 generates a power signal for driving the motor 136 using an inverter or the like, and supplies the power signal to the motor 136 via the power cable 140. The motor 136 is an electric motor that is driven by the power signal supplied from the power cable 140.

[0277] The power cable 140 has a power line 141 and a GND line 142. The power line 141 is a wiring for transmitting power signals, and is composed of three lines to which three-phase AC signals corresponding to, for example, the U phase, V phase, and W phase are supplied. The GND line 142 is a wiring for connecting the GND portions of the servo amplifier 135 and the motor 136.

[0278] The power generation device 850 has a rectifier circuit 30 and an inductor element 145, and is used by being inserted midway along the GND line 142 of the power cable 140. As shown in Figure 43, the first input terminal 31a of the rectifier circuit 30 is connected to the GND line 142a connected to the motor 136, and the second input terminal 31b is connected to the GND line 142b connected to the servo amplifier 135.

[0279] Furthermore, inductor element 145 is connected between GND line 142a and GND line 142b. That is, inductor element 145 functions as part of GND line 142 in power cable 140. As a result, GND line 142a and GND line 142b function as a single wiring that passes a DC component. Therefore, even if power generation device 850 is inserted into GND line 142, the GND portions of servo amplifier 135 and motor 136 are not separated.

[0280] In the power generation device 850 configured in this manner, noise generated by the inverter constituting the servo amplifier 135, noise generated by driving the motor 136, and the like are harvested as electric power. For example, the servo amplifier 135 and the motor 136 use relatively large amounts of electric power, so it is conceivable that the noise level will also be large. By converting such noise into electric power, it is possible to significantly improve the amount of electric power harvested.

[0281] By providing the inductor element 145, it is possible to prevent the GND line 142 from being DC disconnected. This makes it possible to harvest power without affecting the operation of the servo amplifier 135 and the motor 136. It is also possible to improve the amount of power harvested by matching with the noise source.

[0282] Furthermore, the power generation device 850 has the effect of lowering the noise level by converting noise generated by the servo amplifier 135 and the motor 136 into electric power. This makes it possible to realize a clean GND environment, for example, in the device GND connected to the GND line 142. It also makes it possible to suppress the radiation of electromagnetic waves caused by noise around the servo amplifier 135 and the motor 136.

[0283] The first output terminal 32a and the second output terminal 32b of the rectifier circuit 30 are connected to, for example, a storage element for harvesting power, but other elements may also be connected. For example, for noise reduction, a load resistor may be connected between the first output terminal 32a and the second output terminal 32b. In this case, the load resistor can be appropriately selected according to the desired noise reduction level. Furthermore, if the only purpose is noise reduction, a load resistor need not be connected. With this structure, the generated noise is rectified as direct current and returned to the GND line 142, thereby achieving greater noise reduction. The ripple removal capacitor downstream of the rectifier circuit 30 can also be appropriately configured to remove noise frequency components, thereby lowering the noise floor. Furthermore, matching the inductor element 145 to the noise source can also improve noise reduction.

[0284] The power harvested by the power generation device 850 is supplied to, for example, a sensor that monitors the state of the motor 136 (the number of rotations, temperature, vibration, operating noise, etc. of the motor 136). Power may also be supplied to a sensor that monitors the operating environment of the motor 136. Of course, the use of the power generation device 850 is not limited, and the power generation device 850 may be used for other purposes.

[0285] 44 is a schematic diagram showing an example configuration of a power cable unit 860 including a power generator 850. The power cable unit 860 is a power cable 140 provided with a servo amplifier connector 146 and a motor connector 147 at both ends. The power generator 850 is inserted midway along the power cable 140. Specifically, a case 148 that houses the rectifier circuit 30 and the like of the power generator 850 is provided so as to encase the GND line 142 and power line 141 of the power cable 140.

[0286] 43, the rectifier circuit 30 is connected to the GND line 142 within the case 148. The power line 141 is not connected to other elements within the case 148. The case 148 may also be provided with various circuits and sensors that operate using power from the power generation device 850. By using such a power cable unit 860, it is possible to easily build a system that monitors the state and operating environment of the motor 136, for example.

[0287] Fig. 45 is a block diagram showing another example of the configuration of a power generation device. The power generation device 900 shown in Fig. 45 is a device that switches appropriately between power stored in a storage element 55 such as a capacitor or a battery and power output from a power supply unit 58 provided in an electrical device 1 and supplies the power to a load 90.

[0288] The power generation device 900 has a changeover switch 120. The changeover switch 120 is provided between the load 90 and the power storage unit 40 that charges the power storage element 55. The changeover switch 120 is also connected to the power supply unit 58 of the electrical device 1.

[0289] The configuration of the power generating device 900 other than the changeover switch 120 is the same as that of each of the power generating devices described in the above embodiments. Here, the configuration in which the power generating device 900 is connected to the metal body 76 of the electrical device 1 is illustrated, but if, for example, a heat sink or the like is used as the metal body 76, the power generating device 900 can also be configured to include the metal body 76.

[0290] The changeover switch 120 is a switch element that switches between connecting either the storage element 55 or the power supply unit 58 provided in the electrical device 1 to the load 90. Specifically, the changeover switch 120 switches the supply source that supplies power to the load 90 between the power supply unit 58 or the storage element 55 in response to a predetermined control signal (hereinafter referred to as a switching signal).

[0291] For example, the load 90 is an electric circuit (such as a sensor module or a communication module) that is provided in the electric device 1 and performs a predetermined operation, or a peripheral device (such as a remote control or a controller) that is used with the electric device 1. Normally, standby power or the like is supplied to the load 90 from the power supply unit 58 of the electric device 1, but by using this configuration, it is possible to supply power to the load 90 from the storage element 55 of the power generation device 900. In this way, the power generation device 900 can reduce the standby power of the electric device 1 by using the power charged in the storage element 55.

[0292] Fig. 46 is a flowchart showing an example of a power supply operation using the storage element 55 of the power generation device 900. The process shown in Fig. 46 is a process in which, when the voltage of the storage element 55 reaches a predetermined voltage, the changeover switch 120 is switched to stop the power supply from the device side and start the power supply from the storage element 55.

[0293] In step 101, power is harvested from the metal body 76 by the power generation device 900. In step 102, the harvested power is charged into the power storage element 55.

[0294] In step 103, it is determined whether the voltage of the storage element 55 is equal to or greater than a predetermined voltage (threshold value). This process is executed, for example, by the power storage unit 40, which monitors the voltage of the storage element 55. Here, the predetermined voltage is, for example, the voltage when the storage element 55 is fully charged. Note that in addition to determining the voltage of the storage element 55, it is also possible to determine, for example, the time since a certain voltage was reached.

[0295] If the voltage of the storage element 55 is less than the predetermined threshold value (No in step 103), step 103 is executed again, for example, after a certain period of time has elapsed, to determine the voltage of the storage element 55. This process is executed repeatedly while the storage element 55 is being charged.

[0296] In step 104, if the voltage of the storage element 55 is equal to or higher than a predetermined threshold value (Yes in step 103), it is determined that the storage element 55 is sufficiently charged (for example, fully charged), and a switching signal is output from the storage unit 40 to the selector switch 120 to switch the connection to the power generation device 900. When the switching signal is output, a signal to stop the supply of standby power may be output to the power supply unit 58.

[0297] In step 105, while standby power is being supplied from the power supply unit 58 to the load 90, it is detected whether the changeover switch 120 is outputting a switching signal to the power generation device 900. For example, if a switching signal to the power generation device 900 is not detected (No in step 105), step 101′, which will be described later, is executed, and the state in which standby power is supplied from the power supply unit 58 to the load 90 is maintained.

[0298] If a switching signal to the power generation device 900 is detected (Yes in step 105), in step 106, the changeover switch 120 switches the power source connected to the load 90 from the power supply unit 58 to the storage element 55. That is, the connection between the power supply unit 58 and the load 90 is switched OFF, and the connection between the storage element 55 and the load 90 is switched ON. As a result, standby power is supplied to the load 90 from the storage element 55 of the power generation device 900.

[0299] Furthermore, when the supply of power from the storage element 55 to the load 90 is completed (for example, when the voltage of the storage element 55 drops below a certain value or when the operation of the load 90 is no longer necessary), the changeover switch 120 switches the power source connected to the load 90 from the storage element 55 to the power supply unit 58. Therefore, when the processing from step 101 to step 106 is completed, power is supplied from the power supply unit 58 to the load 90, and charging of the storage element 55 begins again.

[0300] 46 , when the voltage of the storage element 55 reaches a predetermined voltage, the changeover switch 120 connects the storage element 55 to the load 90. This allows the power supply from the power supply unit 58 to the load 90 to be taken over by the power generation device 900 each time charging of the storage element 55 is completed. This makes it possible to reduce the power consumption of the electrical appliance 1.

[0301] 46, step 101' is executed in parallel with the processes of steps 101 to 104. In step 101', the selector switch 120 is controlled to connect the power supply unit 58 of the electrical device 1 to the load 90, and standby power from the power supply unit 58 is supplied to the load 90. This makes it possible to supply necessary power to the load 90 as needed even while the storage element 55 is being charged.

[0302] Fig. 47 is a flowchart showing another example of the power supply operation using the storage element 55 of the power generation device 900. The process shown in Fig. 47 is a process in which a predetermined signal (request signal) is generated when it is necessary to switch the power source for the load 90 on the electrical device 1 side, and the changeover switch 120 is switched in response to the signal.

[0303] While standby power is being supplied from power supply unit 58 to the load, power generation device 900 executes steps 201 to 203. This process is similar to, for example, steps 101 to 103 shown in FIG. 46 . In step 204, if the voltage of storage element 55 reaches or exceeds a predetermined voltage (Yes in step 203), a standby mode is initiated in power storage unit 40. The standby mode is, for example, a mode in which the voltage of storage element 55 is maintained in a fully charged state, and control is performed, for example, by cutting off charging of storage element 55 to prevent storage element 55 from being overcharged.

[0304] In step 205, it is determined whether or not a request signal is present. The request signal is a signal generated in the electric device 1 when, for example, it becomes necessary to supply electric power from the power storage element 55 of the power generation device 900 to the load 90.

[0305] For example, if it is known that the storage element 55 is charged at regular time intervals, the request signal may be generated when it is determined that the storage element 55 has been charged. Furthermore, when an operation to be performed while the electrical device 1 is in standby mode (for example, downloading a program update file or sensing at regular intervals using various sensors) is to be performed, the request signal is generated to supply power from the storage element 55. In addition, the timing for generating the request signal is not limited, and the request signal can be generated at any timing depending on the type and use of the electrical device 1.

[0306] If a request signal has not been output (No in step 205), step 205 is executed again, for example, at regular intervals. On the other hand, if a request signal has been output (Yes in step 205), a switching signal for switching the connection to the power generation device 900 is output to the selector switch 120 in step 206. The switching signal may be generated by the electric device 1, or may be generated by the power storage unit 40 that has received the request signal from the electric device 1.

[0307] In step 207, while standby power is being supplied from the power supply unit 58 to the load 90, it is detected whether a switching signal to the power generation unit 900 is being output by the changeover switch 120. For example, if a switching signal to the power generation unit 900 is not detected (No in step 207), step 201' is executed, and the state in which standby power is supplied from the power supply unit 58 to the load 90 is maintained. Note that step 201' is the same process as step 101' shown in FIG.

[0308] If a switching signal to the power generation device 900 is detected (Yes in step 207), in step 208, the changeover switch 120 switches the power source connected to the load 90 from the power supply unit 58 to the storage element 55. As a result, standby power is supplied to the load 90 from the storage element 55 of the power generation device 900.

[0309] 47 , when a predetermined signal (request signal) is output from the electric device 1, the changeover switch 120 connects the storage element 55 to the load 90. This makes it possible to supply the power of the storage element 55 charged by the power generation device 900 to the load when needed on the electric device 1 side. This makes it possible to use the power from the power generation device 900 to replace the power required for various processes and operations performed while the electric device 1 is in standby mode.

[0310] The power generation device of this technology can supply power to electronic devices and their peripherals by converting electromagnetic noise generated by electronic devices into electricity, enabling efficient energy utilization. Therefore, the power generation device of this technology can be related to Goal 7 "Affordable and Clean Energy" of the Sustainable Development Goals (SDGs) adopted at the United Nations Summit in 2015.

[0311] It is also possible to combine at least two of the features of the present technology described above. That is, the various features described in each embodiment may be arbitrarily combined without distinguishing between the embodiments. Furthermore, the various effects described above are merely examples and are not intended to be limiting, and other effects may also be achieved.

[0312] In the present disclosure, the terms "same," "equal," "orthogonal," etc. are concepts that include "substantially the same," "substantially equal," "substantially orthogonal," etc. For example, they also include states that fall within a predetermined range (e.g., a range of ±10%) based on "completely the same," "completely equal," "completely orthogonal," etc.

[0313] The present technology may also be configured as follows. (1) A power generating device comprising: a transmission unit provided in an electric device and connected directly or by capacitive coupling to at least one heat sink having a potential different from that of a GND of the electric device, the transmission unit transmitting AC power of electromagnetic noise generated on the at least one heat sink; and a rectifier circuit rectifying the AC power transmitted by the transmission unit to output DC power. (2) The power generating device according to (1), further comprising: a high-pass filter provided between the heat sink connected to the transmission unit and the GND of the electric device. (3) The power generating device according to (2), wherein the high-pass filter passes AC components in a frequency band higher than the frequency band rectified by the rectifier circuit. (4) The power generating device according to (2) or (3), wherein the high-pass filter is configured solely by a capacitor, or as a parallel circuit of a capacitor and a resistor. (5) The power generating device according to at least one of (1) to (4), wherein the rectifier circuit has a pair of input terminals, and the transmission unit connects different heat sinks to the pair of input terminals, respectively, or connects the heat sink to one of the pair of input terminals. (6) The power generating device according to (5), wherein the electrical device has a primary side circuit to which power is supplied from a predetermined power source and a secondary side circuit electrically isolated from the primary side circuit, the at least one heat sink is provided in either the primary side circuit or the secondary side circuit, and the rectifier circuit is provided on the same side of the primary side circuit or the secondary side circuit as the at least one heat sink. (7) The power generating device according to (5) or (6), wherein the transmission unit electrically connects the input terminals and the heat sink. (8) The power generating device according to (7), further comprising a high-pass filter provided between the heat sink connected to the transmission unit and the GND of the electrical device, wherein the transmission unit connects different heat sinks to the pair of input terminals, respectively, and the high-pass filter is provided on at least one of the heat sinks connected to the pair of input terminals.(9) The power generating device according to (7), wherein the transmission unit connects the heat sink to one of the pair of input terminals and connects the GND of the electric device to the other of the pair of input terminals directly or via a capacitor. (10) The power generating device according to at least one of (1) to (5), wherein the electric device has a primary side circuit to which power is supplied from a predetermined power source and a secondary side circuit electrically isolated from the primary side circuit, the at least one heat sink is provided in the primary side circuit, and the rectifier circuit is provided in the secondary side circuit. (11) The power generating device according to (5), wherein the transmission unit has a transformer and connects the input terminal and the heat sink via the transformer. (12) The power generating device according to (11), further comprising: a high-pass filter provided between the heat sink connected to the transmission unit and a GND of the electrical device, wherein the transmission unit connects different heat sinks to the pair of input terminals, respectively, and the high-pass filter is provided on one of the heat sinks connected to the pair of input terminals. (13) The power generating device according to (11), wherein the transmission unit connects the heat sink to one of the pair of input terminals and connects the GND of the electrical device to the other of the pair of input terminals via a capacitor. (14) The power generating device according to (5), wherein the transmission unit has an insulating sheet arranged in contact with the heat sink and a conductive sheet connected to the heat sink by capacitive coupling via the insulating sheet, and the input terminal is connected to the conductive sheet. (15) The power generating device according to at least one of (5) to (14), wherein the at least one heat sink includes a plurality of heat sinks, the transmission unit has a conductive member that electrically connects two or more of the plurality of heat sinks, and the two or more heat sinks connected by the conductive member are connected to the input terminal. (16) The power generating device according to at least one of (1) to (15), further comprising: a power storage unit that has a storage element that stores DC power output from the rectifier circuit and controls charging or discharging of the storage element depending on a charging state of the storage element.(17) The power generating apparatus according to (16), wherein the storage element is a battery, and the storage unit has a charge control unit provided between the battery and the rectifier circuit and configured to charge the battery according to a charging status of the battery. (18) The power generating apparatus according to (16), wherein the storage element is a battery, and the storage unit has a first switch element provided between the battery and the rectifier circuit, and a first switching control unit that switches the first switch element OFF when the voltage of the battery becomes equal to or higher than a first threshold voltage. (19) The power generating apparatus according to (16), wherein the storage element is a capacitor, and the storage unit has a second switch element provided between the capacitor and a load to which power of the capacitor is supplied, and a second switching control unit that switches the second switch element ON when the voltage of the capacitor becomes equal to or higher than a second threshold voltage. (20) The power generating device according to (16) to (19), wherein the power storage unit includes a protection diode that protects a control element for controlling charging or discharging of the power storage element. (21) The power generating device according to at least one of (1) to (20), wherein the diodes constituting the rectifier circuit have a ratio of a forward current at a forward voltage to a reverse current when the voltage is applied in the reverse direction of 4700 or more. (22) The power generating device according to at least one of (1) to (21), wherein the diodes constituting the rectifier circuit have a resistance of 1.4 MΩ or more when calculated from a reverse current when a reverse voltage is set to 10 V. (23) The power generating device according to at least one of (1) to (22), wherein the diodes constituting the rectifier circuit are silicon diodes. (24) The power generating device according to at least one of (1) to (23), further comprising the at least one heat sink. (25) The power generating device according to (24), wherein the heat sink is provided in close contact with a semiconductor element in the electrical device. (26) The power generating device according to (24) or (25), wherein the material of the heat sink includes at least one of aluminum, copper, iron, and tin.(27) A power generating device according to at least one of (1) to (26), wherein the electrical equipment is industrial equipment. (28) An electrical equipment comprising: a power generating device having: at least one heat sink having a potential different from that of GND; a transmission unit connected to the at least one heat sink directly or by capacitive coupling, and transmitting AC power of electromagnetic noise generated on the at least one heat sink; and a rectifier circuit rectifying the AC power transmitted by the transmission unit to output DC power. (29) A connection method for energy harvesting, comprising: connecting a transmission unit, which transmits AC power of electromagnetic noise generated on the at least one heat sink, to at least one heat sink having a potential different from that of GND of the electrical equipment directly or by capacitive coupling, and connecting the transmission unit to a rectifier circuit that rectifies the AC power to output DC power. (30) A power generating device comprising: a transmission unit provided in an electric device and connected directly or by capacitive coupling to at least one metal body having a potential different from that of the earth GND, and transmitting AC power of electromagnetic noise generated in the at least one metal body, and a rectifier circuit that rectifies the AC power transmitted by the transmission unit and outputs DC power. (31) The power generating device according to (30), wherein the rectifier circuit has a pair of input terminals, and the at least one metal body includes at least one of a first metal body provided in a first electric device or a second metal body provided in a second device different from the first device, and the transmission unit connects the first metal body to one of the pair of input terminals and connects the second metal body to the other of the pair of input terminals. (32) The power generating device according to (31), wherein the first electric device and the second electric device each include a noise source that generates the electromagnetic noise. (33) The power generating device according to (31) or (32), wherein the transmission unit connects the first metal body and the second metal body to the pair of input terminals via a signal cable connecting the first electric device and the second electric device. (34) The power generating device according to (33), wherein the transmission unit connects the first metal body and the second metal body to the pair of input terminals via a GND line of the signal cable.(35) The power generating device according to (33) or (34), wherein the power generating device is configured as any one of a cable unit including the signal cable, a relay unit that relays the signal cable, and a connector unit to which the signal cable is connected in the electrical device. (36) The power generating device according to (31), wherein the power generating device is provided in a third electrical device to which the first electrical device is connected by a first signal cable and the second electrical device is connected by a second signal cable, and the transmission unit connects the first metal body to one of the pair of input terminals via the first signal cable and connects the second metal body to the other of the pair of input terminals via the second signal cable. (37) The power generating device according to at least one of (31) to (36), wherein the transmission unit has a first transmission line connected to the first metal body, a second transmission line connected to the second metal body, and an inductor element provided between the first transmission line and the second transmission line. (38) The power generation device according to (37), wherein the Q value of the inductor element in a frequency band to be harvested is 10 or more. (39) The power generation device according to at least one of (30) to (38), wherein the at least one metal body includes a heat sink provided in the electric device and having a potential different from that of a GND of the electric device. (40) The power generation device according to at least one of (30) to (39), further comprising: a storage element that stores DC power output from the rectifier circuit; and a changeover switch that selects and connects either the storage element or a power supply unit provided in the electric device to a load. (41) The power generation device according to (40), wherein the changeover switch connects the storage element to the load when the voltage of the storage element reaches a predetermined voltage or when a predetermined signal is output from the electric device.

[0314] DESCRIPTION OF SYMBOLS 1...electrical equipment 3...semiconductor element 4...ground pattern 10...heat sink 20...transmission section 23...transformer 30...rectifier circuit 40...energy storage section 50...high-pass filter 55...energy storage element 61...primary side circuit 62...secondary side circuit 70...insulating sheet 71...conductive sheet 76...metal body 100, 100a to 100d, 200, 200a to 200c, 210, 211, 212, 300, 400, 500, 600, 700, 800, 850, 900...power generation device

Claims

1. A power generation device comprising: a transmission unit that is provided in an electrical device and is connected directly or by capacitive coupling to at least one heat sink that has a different potential from the GND of the electrical device, and transmits AC power of electromagnetic noise generated on the at least one heat sink; and a rectifier circuit that rectifies the AC power transmitted by the transmission unit to output DC power.

2. A power generating device according to claim 1, further comprising a high-pass filter provided between the heat sink connected to the transmission section and the GND of the electrical device.

3. A power generating device according to claim 2, wherein said high-pass filter passes AC components in a frequency band higher than the frequency band rectified by said rectifier circuit.

4. A power generating device according to claim 1, wherein the rectifier circuit has a pair of input terminals, and the transmission section connects different heat sinks to the pair of input terminals, respectively, or connects the heat sink to one of the pair of input terminals.

5. A power generating device according to claim 4, wherein the transmission section electrically connects the input terminal and the heat sink.

6. A power generating device as claimed in claim 5, further comprising a high-pass filter provided between the heat sink connected to the transmission section and the GND of the electrical device, the transmission section connecting different heat sinks to the pair of input terminals, respectively, and the high-pass filter being provided on at least one of the heat sinks connected to the pair of input terminals.

7. A power generating device according to claim 5, wherein the transmission section connects the heat sink to one of the pair of input terminals, and connects the other of the pair of input terminals to the GND of the electrical device directly or via a capacitor.

8. A power generating device as claimed in claim 1, wherein the electrical equipment has a primary circuit to which power is supplied from a predetermined power source and a secondary circuit electrically isolated from the primary circuit, the at least one heat sink is provided in the primary circuit, and the rectifier circuit is provided in the secondary circuit.

9. A power generating device according to claim 4, wherein the transmission section has a transformer, and the input terminal and the heat sink are connected via the transformer.

10. A power generating device as described in claim 9, further comprising a high-pass filter provided between the heat sink connected to the transmission section and the GND of the electrical device, the transmission section connecting different heat sinks to the pair of input terminals, respectively, and the high-pass filter being provided on one of the heat sinks connected to the pair of input terminals.

11. A power generating device according to claim 9, wherein the transmission section connects the heat sink to one of the pair of input terminals, and connects the GND of the electrical device to the other of the pair of input terminals via a capacitor.

12. A power generating device as described in claim 4, wherein the transmission section has an insulating sheet arranged in contact with the heat sink, and a conductive sheet connected to the heat sink by capacitive coupling via the insulating sheet, and the input terminal is connected to the conductive sheet.

13. A power generation device as described in claim 4, wherein the at least one heat sink includes a plurality of heat sinks, and the transmission section has a conductive member that electrically connects two or more of the plurality of heat sinks, and connects the two or more heat sinks connected by the conductive member to the input terminal.

14. The power generating device according to claim 1, further comprising a power storage unit having a storage element for storing DC power output from the rectifier circuit and controlling charging or discharging of the storage element according to the charging state of the storage element.

15. A power generating device according to claim 14, wherein the storage element is a battery, and the storage unit has a charge control unit provided between the battery and the rectifier circuit and configured to charge the battery in accordance with the charging status of the battery.

16. A power generating device according to claim 14, wherein the storage element is a battery, and the storage unit has a first switch element provided between the battery and the rectifier circuit, and a first switching control unit that switches the first switch element to OFF when the voltage of the battery becomes equal to or higher than a first threshold voltage.

17. A power generating device according to claim 14, wherein the storage element is a capacitor, and the storage unit has a second switch element provided between the capacitor and a load to which the power of the capacitor is supplied, and a second switching control unit that switches the second switch element to ON when the voltage of the capacitor becomes equal to or higher than a second threshold voltage.

18. The power generating device according to claim 1, further comprising said at least one heat sink.

19. The power generating device according to claim 1, wherein the electrical equipment is industrial equipment.

20. An electrical device comprising: at least one heat sink having a different potential from GND; a transmission unit connected directly or by capacitive coupling to the at least one heat sink, which transmits AC power of electromagnetic noise generated on the at least one heat sink; and a rectifier circuit which rectifies the AC power transmitted by the transmission unit and outputs DC power.

21. A power generation device comprising: a transmission unit that is provided in an electrical device and connected directly or by capacitive coupling to at least one metal body having a different potential from the earth GND, and that transmits AC power of electromagnetic noise generated in the at least one metal body; and a rectifier circuit that rectifies the AC power transmitted by the transmission unit and outputs DC power.

22. A power generating device as described in claim 21, wherein the rectifier circuit has a pair of input terminals, the at least one metal body includes at least one of a first metal body provided in a first electrical device or a second metal body provided in a second device different from the first device, and the transmission section connects the first metal body to one of the pair of input terminals and connects the second metal body to the other of the pair of input terminals.

23. The power generating device according to claim 22, wherein the first electrical device and the second electrical device each include a noise source that generates the electromagnetic noise.

24. A power generating device according to claim 22, wherein the transmission section connects the first metal body and the second metal body to the pair of input terminals via a signal cable connecting the first electrical device and the second electrical device.

25. A power generating device according to claim 24, wherein the transmission section connects the first metal body and the second metal body to the pair of input terminals via a GND line of the signal cable.

26. A power generating device according to claim 24, wherein the power generating device is configured as any one of a cable unit including the signal cable, a relay unit that relays the signal cable, and a connector unit to which the signal cable is connected in the electrical device.

27. A power generation device as described in claim 22, wherein the power generation device is provided on a third electrical device to which the first electrical device is connected by a first signal cable and the second electrical device is connected by a second signal cable, and the transmission unit connects the first metal body to one of the pair of input terminals via the first signal cable and connects the second metal body to the other of the pair of input terminals via the second signal cable.

28. A power generating device as described in claim 22, wherein the transmission section has a first transmission line connected to the first metal body, a second transmission line connected to the second metal body, and an inductor element provided between the first transmission line and the second transmission line.

29. A power generating device according to claim 28, wherein the Q value of the inductor element in the frequency band to be harvested is 10 or more.

30. A power generating device according to claim 21, wherein said at least one metal body includes a heat sink provided in said electrical device and having a different potential from the GND of said electrical device.

31. A power generating device according to claim 21, further comprising: a storage element for storing DC power output from said rectifier circuit; and a change-over switch for selectively connecting either said storage element or a power supply unit provided in said electrical device to a load.

32. A power generating device according to claim 31, wherein the changeover switch connects the storage element to the load when the voltage of the storage element reaches a predetermined voltage or when a predetermined signal is output from the electrical equipment.

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