Energy harvesting system

Abstract

Provided is an energy harvesting device that can effectively utilize surplus power and stably supply generated power. [Solution] The system comprises an energy harvesting unit that performs energy harvesting, a power supply unit that receives power generated by the energy harvesting unit and supplies it to an external load, a first power storage unit that receives power generated by the energy harvesting unit and stores the power, a monitoring unit that monitors the input voltage to the power supply unit and the output voltage from the power supply unit to the load, and a supply control unit that controls the destination of the power generated by the energy harvesting unit according to the monitoring results of the monitoring unit.

Description

[Technical Field]

[0001] This invention relates to an energy harvesting device that performs energy harvesting. [Background technology]

[0002] Power generation systems that generate electricity using natural energy have been disclosed. For example, Patent Document 1 discloses a power generation system that is composed of a power generation device that generates solar power, a power conditioner, a measuring device, and a load device, and that switches the output destination of part of the generated power from the power conditioner to the load device when the amount of power generated by the power generation device exceeds the output capacity of the power conditioner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2016-159770 Summary of the Invention [Problem to be solved by the invention]

[0004] Regardless of the power generation system described in Patent Document 1, in an environmental power generation device that performs environmental power generation, which is a technology that converts minute energy into electricity, even if surplus power is generated because the power generated by the power generation device exceeds the power consumed by the load device, the surplus power cannot be effectively utilized.

[0005] Furthermore, because energy harvesting involves minute amounts of energy, there are cases where the power generated by the energy harvester falls short of the power consumed by the load device, which can cause the power supply from the energy harvester to the load device to become unstable.

[0006] The present invention has been made in consideration of the above-mentioned points, and has an object to provide an energy harvesting device that can effectively utilize surplus power and stably supply generated power. [Means for solving the problem]

[0007] The energy harvesting device according to the present invention is characterized by comprising: an energy harvesting unit that performs energy harvesting; a power supply unit that receives power generated by the energy harvesting unit and supplies power to an external load; a first power storage unit that receives power generated by the energy harvesting unit and stores said power; a monitoring unit that monitors the input voltage to the power supply unit and the output voltage from the power supply unit to the load; and a supply control unit that controls the destination of the power generated by the energy harvesting unit according to the monitoring results of the monitoring unit. [Brief explanation of the drawings]

[0008] [Figure 1] This is a perspective view of the energy harvesting device according to Example 1. [Figure 2] This is a block diagram showing an example of the configuration of an energy harvesting device according to Example 1. [Figure 3] This diagram shows the main power flow in the energy harvesting device according to Example 1. [Figure 4] This graph shows the relationship between current and voltage, and the relationship between power and voltage, obtained in solar power generation. [Figure 5] This graph shows an example of the voltage change measured in the energy harvesting system according to Example 1. [Figure 6] This graph shows an example of the change in input voltage to the energy harvesting device according to Example 1. [Figure 7] This graph shows an example of the change in input voltage to the energy harvesting device according to Example 1. [Figure 8] This diagram shows the main power flow in the block diagram of the energy harvesting system according to Example 1. [Figure 9] This diagram shows the main power flow in the block diagram of the energy harvesting system according to Example 1. [Figure 10] This graph shows an example of the change in output voltage from the energy harvesting device according to Example 1. [Figure 11] This graph shows an example of the change in output voltage from the energy harvesting device according to Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiments of the present invention will be described in detail below. In the following description and accompanying drawings, substantially identical or equivalent parts are denoted by the same reference numerals. [Example]

[0010] [Overview of the Energy Harvesting Device 100] First, an overview of the energy harvesting apparatus 100 according to Example 1 will be described using Figure 1. Figure 1 is a perspective view of the energy harvesting apparatus 100 according to Example 1. The energy harvesting apparatus 100 consists of a power generation module 10 that generates electricity and a circuit module 20 connected to the power generation module 10.

[0011] The power generation module 10, which functions as an energy harvesting unit, is a flat, plate-shaped photovoltaic power generation module with a rectangular top surface that generates electricity by receiving sunlight. The power generation module 10 has a photovoltaic panel SP consisting of multiple cells on one of its main surfaces.

[0012] The energy harvesting device 100 is installed in a location where there is nothing to obstruct sunlight, such as the exterior wall or rooftop of a structure, such that the solar panels SP of the power generation module 10 continuously receive sunlight.

[0013] The circuit module 20 is a flat circuit board with a rectangular top surface and is electrically connected to the power generation module 10 via a connector CN. The circuit module 20 includes a circuit consisting of multiple electronic components for supplying the power generated by the power generation module 10 to an external load device.

[0014] Note that the solar panel SP and electronic components mounted on the circuit module 20 of the power generation module 10 shown in Figure 1 are only schematically shown for illustrative purposes, and the actual device configuration is not limited to the illustrated configuration.

[0015] [Configuration of circuit module 20] Next, the configuration of the circuit module 20 will be described with reference to Fig. 2. Fig. 2 is a block diagram showing an example of the configuration of the energy harvesting device 100 according to the first embodiment. Solid lines in the figure indicate electrical paths related to the power supply between the circuit blocks that make up the energy harvesting device 100. Furthermore, dashed lines in the figure indicate paths for measuring line voltage or current, or paths for command signals between blocks.

[0016] The energy harvesting IC 21 is an integrated circuit that receives power generated by the power generation module 10 and supplies power to the load LD connected to the energy harvesting IC 21. In other words, in this embodiment, the energy harvesting IC 21 functions as a power supply unit that supplies power to the load LD.

[0017] The energy harvesting IC21 functions as a DC / DC converter that boosts the input voltage to the energy harvesting IC21 to the operating voltage of the load LD and outputs it. The energy harvesting IC21 is a power management IC used, for example, in the ADP5091 manufactured by ANALOG DEVICES.

[0018] In this embodiment, the load LD that receives power from the energy harvesting IC21 and consumes power can be, for example, devices that operate on small amounts of power, such as temperature and humidity sensors, motion sensors, wearable devices, and IoT devices.

[0019] The switching circuit 23 is a power supply path switching circuit that switches the power generated by the power generation module 10 to either the main line L1 or the sub-line L2 shown in Figure 2, in response to an external switching control signal.

[0020] The circuit power supply 24 is a power supply unit that receives power from the main line L1 and supplies power to each of the circuits mounted on the circuit module 20. For example, the circuit power supply 24 converts the input voltage received from the main line L1 to a low voltage and supplies it to each circuit of the circuit module 20.

[0021] The voltage monitoring circuit 25 as a monitoring unit is a circuit that monitors the input voltage input to the energy-harvesting IC 21 and the output voltage output from the energy-harvesting IC 21, and outputs the monitoring results. For example, the voltage monitoring circuit 25 monitors whether the output voltage output from the energy-harvesting IC 21 deviates from predetermined upper and lower limit values.

[0022] The supply path control circuit 26 is a control circuit that controls each circuit in the circuit module 20. The supply path control circuit 26 controls the supply path of power supplied to the energy-harvesting IC 21 according to the power generated by the power generation module 10 and the power that the energy-harvesting IC 21 can accept.

[0023] Specifically, the supply path control circuit 26 acquires the monitoring result output by the voltage monitoring circuit 25, and transmits a switching signal to the switching circuit 23 to switch the power supply path to the main line L1 or the sub-line L2 according to the monitoring result. That is, in this embodiment, the supply path control circuit 26 functions as a supply control unit that controls the power supply path.

[0024] The first power storage unit 27 is a power storage device that receives power generated by the power generation module 10 via the main line L1 and stores the power. The first power storage unit 27 is, for example, an electric double layer capacitor (EDLC). Note that the first power storage unit 27 can also supply power to the main line L1 by discharging.

[0025] The charge / discharge control circuit 28 is a circuit that, under the control of the supply path control circuit 26, charges the first power storage unit 27 with the power generated by the power generation module 10 via the main line L1, or discharges the power stored in the first power storage unit 27 to the energy harvesting IC 21 via the main line L1. The charge / discharge control circuit 28 uses the power generation module 10 or the first power storage unit 27 as its operating power source.

[0026] The auxiliary power supply circuit 29 is a power supply circuit that, when supplying power from the first energy storage unit 27 to the energy harvesting IC 21 via the charge / discharge control circuit 28, operates under the control of the supply path control circuit 26 to supplement the power generated by the power generation module 10 to the energy harvesting IC 21.

[0027] The auxiliary power supply circuit 29, for example, boosts the input voltage received from the power generation module 10 to match the voltage of the power discharged from the first energy storage unit 27, and outputs the boosted voltage as the output voltage.

[0028] The second energy storage unit 31 is an energy storage device that receives power from the energy harvesting IC 21, stores the power, and supplies the stored power back to the energy harvesting IC 21. The second energy storage unit 31 is, for example, an electric double-layer capacitor.

[0029] In the energy harvesting device 100 of this embodiment, the supply path control circuit 26 controls the switching circuit 23 in accordance with the changes in the input voltage input to the energy harvesting IC 21 and the output voltage output from the energy harvesting IC 21, and supplies power to the energy harvesting IC 21 in one of the following ways: supplying the power generated by the power generation module 10 to the energy harvesting IC 21 and the first energy storage unit 27; supplying the power generated by the power generation module 10 to the energy harvesting IC 21 only; or supplying the stored power of the first energy storage unit 27 and the power generated by the power generation module 10 to the energy harvesting IC 21.

[0030] [Power supply to the energy harvesting IC 21] The following describes the power supply methods to the energy harvesting IC 21 controlled by the supply path control circuit 26. In this embodiment, the supply path control circuit 26 controls the power supply methods according to the following cases: when the power generated by the power generation module 10 exceeds the power that the energy harvesting IC 21 can accept; when the power generated by the power generation module 10 is in balance with the power that the energy harvesting IC 21 can accept; and when the power generated by the power generation module 10 is below the power that the energy harvesting IC 21 can accept.

[0031] First, using Fig. 3, we will explain how power is supplied to the energy-harvesting IC 21 when the power generated by the power generation module 10 exceeds the power that can be accepted by the energy-harvesting IC 21. Fig. 3 is a block diagram similar to Fig. 2, and the main power supply paths are indicated by thick solid lines.

[0032] Here, the power that can be accepted by the energy-harvesting IC 21 refers to the sum of the power required for the operation of the energy-harvesting IC 21 when the second power storage unit 31 is charged to its maximum and the power required for the operation of the load LD.

[0033] In this embodiment, the power required for the operation of the energy-harvesting IC 21 is the rated power consumption consumed when the energy-harvesting IC 21 is operating stably. Note that the power required for the operation of the energy-harvesting IC 21 may also be power that takes into account the maximum power that the energy-harvesting IC 21 can absorb.

[0034] When the voltage monitoring circuit 25 detects, using a method described below, that the power generated by the power generation module 10 exceeds the power that the energy harvesting IC 21 can accept, in other words, that there is surplus power in the power generated by the power generation module 10, it sends a signal (hereinafter referred to as a charging signal) to the supply path control circuit 26 indicating that charging to the first storage unit 27 is possible.

[0035] When receiving the charging signal transmitted from the voltage monitoring circuit 25, the supply path control circuit 26 controls the switching circuit 23 to switch the power supply path to the main line L1, for example, when the power supply path is the sub-line L2. The supply path control circuit 26 also stops the operation of the auxiliary power supply circuit 29.

[0036] Furthermore, supply path control circuit 26 controls charge / discharge control circuit 28 so that first power storage unit 27 is charged with the power generated by power generation module 10 while monitoring the charging voltage of first power storage unit 27 to be appropriate.

[0037] Through the control of the switching circuit 23 and the charge / discharge control circuit 28 by the supply path control circuit 26, the power generated by the power generation module 10 is supplied to the energy harvesting IC 21, and any surplus power is supplied to the first energy storage unit 27.

[0038] Furthermore, if the power supply path is already set to the main line L1 when the above-mentioned charging signal is received, the supply path control circuit 26 controls only the charge / discharge control circuit 28 to charge the first energy storage unit 27 with generated power.

[0039] Furthermore, the supply path control circuit 26 has an overcharge detection voltage to prevent overcharging of the first energy storage unit 27, and if the charging voltage of the first energy storage unit 27 reaches the overcharge detection voltage, the charging operation of the charge / discharge control circuit 28 is stopped.

[0040] 4 to 7, a method for the voltage monitoring circuit 25 to detect when the power generated by the power generation module 10 exceeds the power that can be accepted by the energy harvesting IC 21 will be described. First, the basic function of the energy harvesting IC 21 will be described using Fig. 4. Fig. 4 is a graph showing the relationship between current and voltage and the relationship between power and voltage obtained in general solar power generation.

[0041] Generally, solar power generation modules have high internal resistance, and the generated voltage decreases when current is output. Therefore, in a solar power generation module, when current is plotted on the left vertical axis and voltage on the horizontal axis, the relationship between current and voltage takes the form of the current-voltage curve shown in Figure 4.

[0042] Furthermore, in a solar power generation module, when power is plotted on the right vertical axis and voltage on the horizontal axis, the relationship between power and voltage is an upward-convex curve, as shown in the power-voltage curve in Figure 4. The current and voltage conditions that result in the maximum generated power on this curve are called the maximum power point (MPP).

[0043] The energy harvesting IC 21 has a function called Maximum Power Point Tracking (MPPT) that performs control to automatically track the maximum power point described above in order to obtain power from the power generation module 10 most efficiently.

[0044] Here, the power generation capacity of a solar power module changes moment by moment depending on the amount of sunlight, and the maximum power point changes accordingly. The voltage at the maximum power point is derived by periodically measuring the open-circuit voltage, which is the voltage when the solar power module is not outputting current. For example, when using a solar power module, the voltage at the maximum power point is about 70-85% of the open-circuit voltage.

[0045] 5 to 7 are diagrams showing changes in voltage when the voltage monitoring circuit 25 monitors the input voltage input to the energy harvesting IC 21. In FIGS. 5 to 7, the open-circuit voltage is V C , the voltage at the maximum power point is V M In the energy harvesting IC 21 of this embodiment, the open circuit voltage V C The measurement period P is set to 16 seconds, and the open-circuit voltage V C The measurement period T1 is set to 256 msec.

[0046] Figure 5 shows the open circuit voltage V C The voltage during the measurement period excluding T1 is always the maximum power point voltage V M This state indicates that the power generated by the power generation module 10 and the power that the energy harvesting IC 21 can accept are in balance.

[0047] In the energy harvesting device 100 of this embodiment, the voltage monitoring circuit 25 monitors the open circuit voltage V C The period excluding the measurement period T1 is set as the voltage monitoring period, and when the voltage during the monitoring period changes from the state shown in Figure 5 to the state shown in Figure 6 or Figure 7 below, it is detected that the power that the power generation module 10 can supply exceeds the power that the energy harvesting IC 21 can accept.

[0048] Figure 6 shows the open circuit voltage VC In addition to the measurement period T1, the input voltage of the energy harvesting IC21 is the open circuit voltage V C 6 shows a state in which there is a period T2 in which the open-circuit voltage V C The period during which they have obtained this certificate is getting longer.

[0049] FIG. 7 shows that during the monitoring period, even though the energy harvesting IC 21 is obtaining power from the power generation module 10, the voltage is at the maximum power point V M The open-circuit voltage V does not drop all the way down. C and voltage V M This represents a state in which the voltage between the

[0050] The states shown in Figures 6 and 7 indicate that the energy harvesting IC 21 cannot receive any more power from the power generation module 10, even if it tries to do so. The voltage monitoring circuit 25 monitors, for example, the generated voltage during the monitoring period described above, as shown in Figure 7, to reach the maximum power point voltage V. M If the power supply voltage Vcc is higher than the power supply voltage Vcc, it is detected that the power generation module 10 can supply exceeds the power that the energy harvesting IC 21 can accept.

[0051] As described above, when the voltage monitoring circuit 25 detects that the power supplyable by the power generation module 10 exceeds the power that the energy harvesting IC 21 can accept, it transmits a charging signal from the voltage monitoring circuit 25 to the supply path control circuit 26. Here, the charging signal instructs the first energy storage unit 27 to be charged and specifies the voltage at the maximum power point V M It includes information about [the subject].

[0052] When the supply path control circuit 26 receives a charging signal transmitted from the voltage monitoring circuit 25, it controls the charge / discharge control circuit 28 to charge the first energy storage unit 27. The supply path control circuit 26 sets the input voltage of the charge / discharge control circuit 28, i.e., the generated voltage of the power generation module 10, to the voltage at the maximum power point V. M Control it so that it becomes like this.

[0053] The voltage monitoring circuit 25 monitors the open circuit voltage VC When the measurement timing of the power generation module 10 reaches the maximum power point voltage V M If the voltage falls below a certain level, a stop signal is sent to the supply path control circuit 26 indicating that the charge / discharge control circuit 28 should stop its charging operation. When the supply path control circuit 26 receives the stop signal sent from the voltage monitoring circuit 25, it stops the charge / discharge control circuit 28 from charging the first energy storage unit 27.

[0054] In the above example, the power that the energy harvesting IC 21 can accept was defined as the sum of the power required for the operation of the energy harvesting IC 21 and the power required for the operation of the load LD when the second energy storage unit 31 is fully charged, but this is not limited to this definition. For example, the power that the energy harvesting IC 21 can accept may be defined as the sum of the power required for the operation of the energy harvesting IC 21, the power required for the operation of the load LD, and the power required for charging the second energy storage unit 31.

[0055] Next, using Figure 8, we will explain the power supply configuration when the power generated by the power generation module 10 and the power that the energy harvesting IC 21 can accept are in balance. Figure 8 is a block diagram similar to Figure 2, with the main power supply paths shown by thick solid lines.

[0056] The method by which the voltage monitoring circuit 25 detects that the power generated by the power generation module 10 and the power that the energy harvesting IC 21 can accept are in balance is the same as the detection method described above, and the only difference from the operation of the supply path control circuit 26 described above is that the first energy storage unit 27 is not charged.

[0057] That is, the voltage monitoring circuit 25 monitors whether the generated voltage is equal to the voltage V M If this is the case, it is detected that the power generated by the power generation module 10 and the power that can be received by the energy harvesting IC 21 are in balance.

[0058] In addition, the balance between the power generated by the power generation module 10 and the power that can be accepted by the environmental power generation IC 21 includes a case where there is room for storing power from the environmental power generation IC 21 in the second power storage unit 31 even if the power generated by the power generation module 10 exceeds the power that can be accepted by the environmental power generation IC 21.

[0059] When the voltage monitoring circuit 25 detects that the power generated by the power generation module 10 and the power that the energy harvesting IC 21 can accept are in balance, it sends a stop signal to the supply path control circuit 26 indicating that the operation of the charge / discharge control circuit 28 should be stopped.

[0060] When the power supply path control circuit 26 receives a stop signal transmitted from the voltage monitoring circuit 25, it stops the operation of the charge / discharge control circuit 28, for example, if the charge / discharge control circuit 28 is charging or discharging the first energy storage unit 27. Also, if the power supply path is sub-line L2, the power supply path control circuit 26 controls the switching circuit 23 to switch the power supply path to main line L1.

[0061] 9 to 11, we will explain the power supply mode when the power generated by the power generation module 10 is lower than the power that can be accepted by the energy-harvesting IC 21. Fig. 9 is a block diagram similar to Fig. 2, and main power supply paths are indicated by thick solid lines.

[0062] Here, the power that can be accepted by the energy-harvesting IC 21 refers to the sum of the power required to operate the energy-harvesting IC 21 and the power required to operate the load LD when there is no power stored in the second power storage unit 31 or when the power stored in the second power storage unit 31 is insufficient to operate the energy-harvesting IC 21 and the load LD.

[0063] When the voltage monitoring circuit 25 detects, using a method described below, that the power that the power generation module 10 can supply is lower than the power that the environmental power generation IC 21 can accept, it sends a signal (hereinafter referred to as the discharge signal) to the supply path control circuit 26 indicating that discharge from the first storage unit 27 is possible.

[0064] When the supply path control circuit 26 receives the discharge signal transmitted from the voltage monitoring circuit 25, for example, if the power supply path is the main line L1, the supply path control circuit 26 controls the switching circuit 23 to switch the power supply path to the sub-line L2. The supply path control circuit 26 also activates the auxiliary power supply circuit 29.

[0065] Furthermore, supply path control circuit 26 controls charge / discharge control circuit 28 to discharge first power storage unit 27 while monitoring the input voltage input to energy harvesting IC 21 to ensure that it is appropriate.

[0066] Under the control of the supply path control circuit 26, the auxiliary power supply circuit 29 boosts the power generated by the power generation module 10 to match the discharge voltage of the first power storage unit 27, and supplies power to the energy harvesting IC 21 in addition to the power discharged from the first power storage unit 27.

[0067] 10 and 11, a method for the voltage monitoring circuit 25 to detect when the power generated by the power generation module 10 falls below the power that can be received by the energy-harvesting IC 21 will be described. Figures 10 and 11 are diagrams showing changes in the output voltage output from the energy-harvesting IC 21.

[0068] In this embodiment, the output voltage from the energy harvesting IC 21 has an upper limit voltage V U and the lower limit voltage V L is set, and the output voltage of the energy harvesting IC21 is set to the upper limit voltage V U Gain power until it reaches

[0069] The energy harvesting IC21 has an output voltage limit of V U When the output voltage starts to drop and reaches the lower limit voltage V L When the voltage reaches 1 V, the energy harvesting IC 21 starts to obtain power again, and the output voltage from the energy harvesting IC 21 starts to rise.

[0070] In this way, the energy-harvesting IC 21 controls the output voltage so that it stabilizes within a certain range while repeatedly increasing and decreasing, resulting in the output voltage from the energy-harvesting IC 21 taking the form shown in Figure 10.

[0071] Here, when the power that the power generation module 10 can supply is lower than the power that the energy harvesting IC 21 can accept, the output voltage output from the energy harvesting IC 21 cannot rise and falls below the lower limit voltage V as shown in FIG. 11, even if the energy harvesting IC 21 continues to obtain power. L continues to fall below this level.

[0072] The energy harvesting IC21 has a lower limit of the output voltage, V L The discharge start threshold voltage V T The voltage monitoring circuit 25 monitors whether the output voltage of the energy harvesting IC 21 is a discharge start threshold V T When the power consumption reaches 100%, it is detected that the power generated by the power generation module 10 is lower than the power that the energy harvesting IC 21 can accept.

[0073] As described above, when the voltage monitoring circuit 25 detects that the power generated by the power generation module 10 is lower than the power that can be received by the energy harvesting IC 21, the voltage monitoring circuit 25 transmits a discharge signal to the supply path control circuit 26. Here, the discharge signal includes an instruction to discharge from the first power storage unit 27.

[0074] When the supply path control circuit 26 receives a discharge signal transmitted from the voltage monitoring circuit 25, it controls the charge / discharge control circuit 28 to discharge from the first energy storage unit 27. The supply path control circuit 26 controls the output voltage of the charge / discharge control circuit 28 (the input voltage of the energy harvesting IC 21) to be equal to the highest open-circuit voltage according to the specifications of the power generation module 10.

[0075] The voltage monitoring circuit 25 monitors whether the output voltage of the energy harvesting IC 21 is an upper limit voltage V UWhen it detects that the voltage monitoring circuit 25 has reached this level, it transmits a stop signal to the supply path control circuit 26, instructing it to stop the discharging operation of the charge / discharge control circuit 28. When the supply path control circuit 26 receives the stop signal transmitted from the voltage monitoring circuit 25, it stops the discharging operation of the charge / discharge control circuit 28.

[0076] Although the power generation module 10 is in a state where it can supply power to the energy-harvesting IC 21, it is insufficient. Therefore, the power generation module 10 adds the power converted by the auxiliary power supply circuit 29 into the charging voltage of the first power storage unit 27 to the power discharged from the first power storage unit 27. This allows the power generated by the power generation module 10 to be used supplementarily.

[0077] When the charging voltage of first power storage unit 27 reaches the overcharge detection voltage, supply path control circuit 26 controls to stop the supply of power to auxiliary power supply circuit 29. Furthermore, when the charging voltage of first power storage unit 27 reaches the overcharge detection voltage, supply path control circuit 26 controls switching circuit 23 to switch the power supply path from sub line L2 to main line L1.

[0078] As described above, according to the energy harvesting device 100 of this embodiment, the supply path control circuit 26 controls the supply of power to the energy harvesting IC 21 and the first power storage unit 27 when the power generated by the power generation module 10 exceeds the power that the energy harvesting IC 21 can accept, and controls the supply of power only to the energy harvesting IC 21 when the power generated by the power generation module 10 and the power that the energy harvesting IC 21 can accept are balanced.

[0079] In addition, when the power generated by the power generation module 10 is lower than the power that the energy-generating IC 21 can accept, the supply path control circuit 26 controls the supply of power from the first power storage unit 27 to the energy-generating IC 21 while supplementarily using the power supplied from the power generation module 10.

[0080] According to the energy harvesting device 100 of this embodiment, the supply path control circuit 26 performs such control, thereby making it possible to effectively utilize surplus power generated by the power generation module 10 while stably supplying power to the energy harvesting IC 21.

[0081] Furthermore, according to the energy harvesting device 100 of this embodiment, surplus generated power can be stored in the first power storage unit 27 without using a device that consumes power at the kW level, such as a power conditioner. Furthermore, since a power conditioner or the like is not required, the device can be expected to be smaller in size.

[0082] In the energy harvesting device 100 of this embodiment, a solar power generation module is used as the power generation module 10, but the present invention is not limited to this, and a module that generates power by another method may also be used.

[0083] For example, a thermoelectric power generation module that generates electricity by utilizing the temperature difference between a relatively high-temperature substance and a relatively low-temperature substance may be adopted as the power generation module 10. Also, for example, a vibration power generation module that generates electricity by utilizing vibrations that occur when people or objects move may be adopted as the power generation module 10.

[0084] In the energy harvesting device 100 of this embodiment, the energy harvesting IC 21 has the second power storage unit 31, but this is not limiting and the energy harvesting IC 21 may not have the second power storage unit 31. In other words, the energy harvesting device 100 may have only the first power storage unit 27. [Explanation of symbols]

[0085] 100 Energy Harvesting Device 10 Power generation module 20 Circuit Module 21 Energy Harvesting IC 23 Switching circuit 24 Circuit power supply 25 Voltage monitoring circuit 26 Supply path control circuit 27 First storage unit 28 Charge / discharge control power supply circuit 29. Subsidized power supply circuit 31. Second Battery Storage Unit

Claims

1. an energy harvesting unit that performs energy harvesting; a power supply unit that receives power generated by the energy harvesting unit and supplies it to an external load; a first power storage unit that receives power generated by the energy harvesting unit and stores the power; a monitoring unit that monitors an input voltage to the power supply unit and an output voltage from the power supply unit to the load; a supply control unit that controls a supply destination of the generated power of the energy harvesting unit in accordance with a monitoring result of the monitoring unit; An energy harvesting device comprising:

2. 2. The energy harvesting device according to claim 1, wherein the supply control unit supplies power to the power supply unit in one of the following ways: supplying the power generated by the energy harvesting unit to the power supply unit and the first power storage unit; supplying the stored power of the first power storage unit and the power generated by the energy harvesting unit to the power supply unit; or supplying the power generated by the energy harvesting unit to the power supply unit.

3. 2. The energy harvesting device according to claim 1, wherein, when the monitoring unit detects that the power generated by the energy harvesting unit exceeds the power that can be received by the power supply unit, the supply control unit supplies the power generated by the energy harvesting unit to the power supply unit and the first power storage unit.

4. 2. The energy harvesting device according to claim 1, wherein when the monitoring unit detects that the power generated by the energy harvesting unit is in balance with the power that can be received by the power supply unit, the supply control unit supplies the generated power to the power supply unit.

5. 2. The energy harvesting device according to claim 1, wherein, when the monitoring unit detects that the power generated by the energy harvesting unit falls below the power that can be received by the power supply unit, the supply control unit supplies the stored power of the first storage unit and the generated power of the energy harvesting unit to the power supply unit.

6. 6. The energy harvesting device according to claim 1, further comprising a second power storage unit that receives power from the power supply unit, stores the power, and supplies the stored power to the power supply unit.

7. 6. The energy harvesting device according to claim 1, wherein the energy harvesting unit is a photovoltaic power generation module that generates power using sunlight.

8. 6. The energy harvesting device according to claim 1, wherein the energy harvesting unit is a thermoelectric power generation module that generates power by utilizing a temperature difference.

Images