JP2015161229A - power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generator capable of achieving improvement of the generation efficiency.SOLUTION: A power generator 1 includes a power generating element 3 and a housing 2. The power generating element 3 includes: a support part 31; a vibration part 32; and a piezoelectric conversion part 33. A first end 32a and second end 32b in the vibration part 32 respectively form a fixed end and a free end. The piezoelectric conversion part 33 is provided overlapping with a part of a surface 321 of the vibration part 32 and generates AC voltage by vibration of the vibration part 32. The housing 2 includes: a fluid inlet 21; a fluid outlet 23; a passage 22; and a fluid introduction part 24 which gathers a fluid flowed from the inlet 21 to the power generating element 3. The power generating element 3 includes a surface area increase part 325 which is formed on the surface 321 of the vibration part 32 by a protruding part and increases a surface area of the vibration part 32.

Description

  The present invention relates to a power generation device, and more particularly to a fluid vibration power generation device that generates power using fluid excitation vibration.

  In recent years, power generation devices that convert vibration energy into electrical energy have attracted attention in fields such as energy harvesting.

  As this type of power generation device, for example, a power generation device 201 having a configuration shown in FIGS. 10A, 10B, and 10C has been proposed (Patent Document 1).

  The power generation apparatus 201 includes a base 211 and a lead 213 to which the piezoelectric element 214 is fixed.

  The base 211 has a plate 215 on which a rectangular window 212 is formed. As shown in FIG. 10A, the size of the window 212 is slightly larger than the lead 213 facing the window 212, and a slight amount of gas F1 passes between the edge of the window 212 and the lead 213. A gap is formed.

  The lead 213 has flexibility that allows bending vibration in the plate thickness direction. For example, the lead 213 is a flexible printed board formed of FRP or the like. The lead 213 is positioned so that one end 231 is fixed to the upper surface of the plate 215 and the other end 232 faces the window 212 so that the window 212 can freely enter and exit.

  Further, as shown in FIG. 10B, the lead 213 is slightly inclined with respect to the upper surface of the plate 215 so that the end 232 is located outside the window 212 (the side into which the gas F1 flows). (Up)

  The piezoelectric element 214 is a bimorph piezoelectric element, and is fixed to both the front and back surfaces of the lead 213 as shown in FIGS. 10 (b) and 10 (c). Patent Document 1 describes that the piezoelectric element 214 may be a unimorph piezoelectric element fixed to one of the front surface and the back surface of the lead 213.

  In the technical field of the fluid vibration power generation device as well as the power generation device 201, further improvement in power generation efficiency is required.

JP 2012-97673 A

  This invention is made | formed in view of the said reason, The objective is to provide the electric power generating apparatus which can aim at the improvement of electric power generation efficiency.

  The power generation device of the present invention includes a power generation element and a housing. The power generation element includes a support portion, a vibration portion, and a piezoelectric conversion portion. The vibration unit includes a first end and a second end. The vibration portion is a fixed end whose first end is fixed to the support portion, and the second end is a free end, and can vibrate upon receiving fluid energy. The piezoelectric conversion unit is provided so as to overlap a part of the surface of the vibration unit, and is configured to generate an alternating voltage by vibration of the vibration unit. The housing includes a fluid inlet, a fluid outlet, a channel between the inlet and the outlet, and a fluid introduction unit that collects the fluid flowing in from the inlet in the power generation element disposed in the channel. And comprising. The power generation element includes a surface area increasing portion that is configured by a convex portion or a concave portion on the surface of the vibrating portion to increase the surface area of the vibrating portion.

  In this power generation device, the power generation element preferably includes a plurality of the surface area increasing portions.

  In this power generation device, the power generation element has a frame shape in the support portion, and there is a gap between the outer surface and the inner surface of the support portion over the entire outer surface of the vibration portion. Here, it is preferable that the surface area increasing portion is provided in an outer peripheral portion in the second region on the second end side of the first region where the piezoelectric conversion unit is provided in the surface of the vibration unit.

  In this power generation device, a power storage unit that stores electrical energy generated by the power generation element, a sensor unit that detects at least one environmental information selected from the group of temperature, humidity, and flow velocity, and the sensor unit detect A transmission unit that transmits environmental information. Here, it is preferable that the power storage unit, the sensor unit, and the transmission unit are held in the housing, and the sensor unit and the transmission unit are configured to operate using the power storage unit as a power source.

  In the power generation device of the present invention, the housing includes a fluid introduction part that collects the fluid flowing in from the inlet into the power generation element disposed in the flow path. Furthermore, in the power generation device of the present invention, the power generation element includes a surface area increasing portion that is configured by a convex portion or a concave portion on the surface of the vibration portion to increase the surface area of the vibration portion. Therefore, the power generation device of the present invention can more efficiently apply the fluid to the vibrating portion of the power generation element, and can improve the power generation efficiency.

Drawing 1 is an outline sectional view showing the power generator of an embodiment. FIG. 2 is a schematic plan view showing the power generation device of the embodiment. Drawing 3 is an outline bottom view showing the power generator of an embodiment. 4 is a schematic YY sectional view of FIG. Fig.5 (a) is a schematic plan view which shows the electric power generation element in the electric power generating apparatus of embodiment. FIG.5 (b) is XX schematic sectional drawing of Fig.5 (a). Fig.6 (a) is a schematic plan view which shows the electric power generation element in the 1st modification of the electric power generating apparatus of embodiment. FIG. 6B is a schematic cross-sectional view taken along the line XX in FIG. Fig.7 (a) is a schematic plan view which shows the electric power generating element in the 2nd modification of the electric power generating apparatus of embodiment. FIG.7 (b) is XX schematic sectional drawing of Fig.7 (a). Fig.8 (a) is a schematic plan view which shows the electric power generation element in the 3rd modification of the electric power generating apparatus of embodiment. FIG.8 (b) is XX schematic sectional drawing of Fig.8 (a). Fig.9 (a) is a schematic plan view which shows the electric power generation element in the 4th modification of the electric power generating apparatus of embodiment. FIG.9 (b) is XX schematic sectional drawing of Fig.9 (a). FIG. 10A is a schematic plan view of a conventional power generator. FIG.10 (b) is XX sectional drawing of Fig.10 (a). FIG. 10C is a YY sectional view of FIG.

  Below, the electric power generating apparatus 1 of this embodiment is demonstrated based on FIGS. 1-4, 5 (a) and 5 (b). 1 is a schematic cross-sectional view taken along the line XX of FIG.

  The power generation device 1 includes a power generation element 3 and a housing 2. The power generating element 3 includes a support part 31, a vibration part 32, and a piezoelectric conversion part 33. The vibration part 32 includes a first end 32a and a second end 32b. The vibration part 32 is a fixed end in which the first end 32a is fixed to the support part 31, and the second end 32b is a free end. The vibration unit 32 can vibrate upon receiving fluid energy. The piezoelectric conversion unit 33 is provided so as to overlap a part of the surface 321 of the vibration unit 32, and is configured to generate an alternating voltage by the vibration of the vibration unit 32. The housing 2 includes a fluid inlet 21, a fluid outlet 23, a flow path 22 between the inlet 21 and the outlet 23, and a fluid flowing from the inlet 21 into the power generation element 3 disposed in the flow path 22. And a fluid introduction part 24 to be collected. The power generating element 3 includes a surface area increasing portion 325 that is formed of a convex portion and increases the surface area of the vibrating portion 32 on the surface 321 of the vibrating portion 32. Therefore, the power receiving device 1 has an increased area for receiving the fluid, and can more efficiently apply the fluid to the vibrating portion 32 of the power generating element 3, thereby improving the power generation efficiency.

  In the power generation device 1, when the fluid hits the vibration unit 32, vibration energy is generated in the vibration unit 32, and electric energy is generated in the piezoelectric conversion unit 33. The piezoelectric conversion unit 33 generates an alternating voltage according to the vibration of the vibration unit 32. Therefore, in the power generation element 3, the voltage generated in the piezoelectric conversion unit 33 is an AC voltage. In the power generation element 3, the absolute value of the peak value of the AC voltage generated in the piezoelectric conversion unit 33 tends to increase as the fluid flow rate increases.

  As shown in FIG. 4, the power generation device 1 includes a power storage unit 4 that stores electrical energy generated by the power generation element 3 and a sensor unit 5 that detects at least one environmental information selected from the group of temperature, humidity, and flow velocity. And the transmission part 6 which transmits the environmental information detected by the sensor part 5 can be set as the structure further provided. The power generation device 1 is preferably configured such that the power storage unit 4, the sensor unit 5, and the transmission unit 6 are held in the housing 21, and the sensor unit 5 and the transmission unit 6 operate using the power storage unit 4 as a power source. Thereby, as for the electric power generating apparatus 1, the freedom degree of an installation place becomes high.

  Each component of the power generator 1 will be described in more detail below.

  The shape of the support part 31 can be, for example, a rectangular frame shape as a frame shape. The inner peripheral shape of the support portion 31 is not limited to a rectangular shape, and may be a polygonal shape other than the rectangular shape, a circular shape, an elliptical shape, or the like. The outer peripheral shape of the support portion 31 may be a shape other than a rectangular shape.

  The vibration part 32 is disposed inside the support part 31 in plan view. Thus, in the power generating element 3, a gap 35 through which a fluid can pass is formed between the outer side surface of the vibrating portion 32 and the inner side surface of the support portion 31.

  The vibration part 32 has a first end 32 a constituted by one end in the length direction of the vibration part 32, and a second end 32 b constituted by the other end in the length direction of the vibration part 32.

  The vibration part 32 is supported by the support part 31 in a swingable manner. The vibration part 32 is supported by the support part 31 so as to be swingable because the part on the first end 32 a side is formed thinner than the support part 31. The vibrating part 32 preferably includes a weight part 34 on the second end 32b side that is thicker than the part on the first end 32a side.

  The vibration part 32 is warped so that the normal line (not shown) of the tip end face 32 c (see FIG. 5B) does not intersect the support part 31. Thereby, the power generation element 3 can perform fluid excitation vibration and can improve the piezoelectric conversion efficiency during the fluid excitation vibration. “Fluid excitation vibration” means the vibration of the vibration part 32 generated when the fluid passes through the gap 35. This fluid excitation vibration is self-excited vibration. Examples of the fluid include air, gas, a mixed gas of air and gas, and liquid. When the fluid is gas, examples of the flow field in which the power generation device 1 is installed include the inside of an air supply duct of an air conditioner and the inside of an exhaust duct of an air conditioner.

  In the power generation element 3, since the vibration part 32 includes the weight part 34, the inertial force at the time of vibration of the vibration part 32 can be increased and the amplitude of the vibration part 32 can be increased as compared with the case where the vibration part 32 is not provided. It becomes possible. In addition, since the vibration part 32 includes the weight part 34, the power generating element 3 is concentrated on the part of the vibration part 32 between the weight part 34 and the support part 31 and the piezoelectric conversion part 33 when the vibration part 32 vibrates. Distortion can be generated. Therefore, the power generation element 3 can improve the piezoelectric conversion efficiency by including the weight portion 34. Further, in the power generating element 3, since the vibration part 32 includes the weight part 34, the resonance frequency of the vibration part 32 can be reduced, and the flow velocity of the fluid at which the vibration part 32 starts to vibrate can be reduced. It becomes possible.

  The power generating element 3 can be manufactured using, for example, a MEMS manufacturing technique.

  In this case, the support part 31 and the vibration part 32 can be formed from a single substrate. Thereby, the power generating element 3 can improve the relative positional accuracy of the support part 31 and the vibration part 32. As the substrate, for example, an SOI substrate in which a silicon layer is formed on an insulating layer made of a silicon oxide film on a silicon substrate can be used.

  The power generation element 3 includes a piezoelectric conversion portion 33 formed on the first surface side of the substrate, and includes an insulating film that electrically insulates the substrate and the piezoelectric conversion portion 33 between the substrate and the piezoelectric conversion portion 33. It is preferable. In this case, in the power generating element 3, the surface 321 of the vibration part 32 is configured by a part of the surface of the insulating film. The insulating film can be composed of, for example, a silicon oxide film. This silicon oxide film can be formed by, for example, a thermal oxidation method, but is not limited thereto, and can also be formed by a CVD method or the like.

  For example, the power generating element 3 can be configured such that the vibration part 32 is warped by the compressive stress of the insulating film. In this case, the power generating element 3 has not only a function of electrically insulating the substrate and the piezoelectric conversion unit 33 but also a function of warping the vibration unit 32 by the insulating film formed on the first surface side of the substrate. . As a result, the power generating element 3 can simplify the manufacturing process as compared with a case where a thin film for stress control is formed on the vibration part 32 separately from the insulating film and the vibration part 32 is warped. In the method for manufacturing the power generating element 3, the internal stress of the insulating film can be controlled by appropriately setting process conditions for forming the insulating film. In the method for manufacturing the power generation element 3, for example, when the insulating film is formed by a thermal oxidation method, the internal stress of the insulating film can be controlled by appropriately setting process conditions such as an oxidation temperature. In the method for manufacturing the power generating element 3, for example, when the insulating film is formed by sputtering or CVD, the internal stress of the insulating film is controlled by appropriately setting process conditions such as gas pressure and temperature. Can do.

  In the initial state where no external vibration or fluid acts on the vibration part 32, the power generation element 3 is warped so that the normal line of the tip surface 32 c of the vibration part 32 does not intersect the support part 31. . Here, the vibration part 32 is warped so that the front surface 321 has a concave curved surface shape and the back surface 322 has a convex curved surface shape.

  The substrate is not limited to an SOI substrate, and a single crystal silicon substrate, a polycrystalline silicon substrate, a magnesium oxide (MgO) substrate, a metal substrate, a glass substrate, a polymer substrate, or the like can also be used.

The piezoelectric conversion unit 33 includes a first electrode, a piezoelectric layer, and a second electrode in order from the vibration unit 32 side. In short, the piezoelectric conversion unit 33 includes a piezoelectric layer, and a first electrode and a second electrode facing each other with the piezoelectric layer sandwiched from both sides in the thickness direction. As the piezoelectric material of the piezoelectric layer, PZT (Pb (Zr, Ti) O ₃ ) is adopted, but not limited to this, for example, PZT-PMN (Pb (Mn, Nb) O ₃ ) or impurities are used. Added PZT may also be used. Further, the piezoelectric material may be AlN, ZnO, KNN (K _0.5 Na _0.5 NbO ₃ ), KN (KNbO ₃ ), NN (NaNbO ₃ ), a material obtained by adding impurities to KNN, or the like. Examples of the impurity include Li, Nb, Ta, Sb, and Cu. In the power generation element 3, the piezoelectric layer is formed of a piezoelectric thin film.

The power generating element 3 may have a structure in which a buffer layer is provided between the insulating film and the first electrode. The buffer layer is a layer provided to improve the crystallinity of the piezoelectric layer on the first electrode. The material of the buffer layer is preferably selected as appropriate according to the piezoelectric material of the piezoelectric layer. When the piezoelectric material of the piezoelectric layer is PZT, it is preferable to employ, for example, SrRuO ₃ , (Pb, La) TiO ₃ , PbTiO ₃ , MgO, LaNiO ₃ or the like as the buffer layer material. Further, the buffer layer may be constituted by a laminated film of a Pt film and a SrRuO ₃ film, for example. The power generating element 3 can improve the crystallinity of the piezoelectric layer by providing a buffer layer.

  In the power generating element 3, the piezoelectric layer of the piezoelectric conversion unit 33 receives stress due to the vibration of the vibration unit 32, and a bias of charge occurs between the second electrode and the first electrode, and an AC voltage is generated in the piezoelectric conversion unit 33. . In short, in the power generating element 3, the piezoelectric conversion unit 33 generates an alternating voltage using the piezoelectric effect of the piezoelectric material.

  The AC voltage generated in the piezoelectric conversion unit 33 is a sinusoidal AC voltage corresponding to the vibration of the piezoelectric layer. The power generation element 3 can generate power using self-excited vibration generated by the fluid flowing through the gap 35. The resonance frequency of the power generation element 3 is determined by the structural parameters, material, and the like of the vibration unit 32.

  The power generating element 3 includes a first pad electrode 36 electrically connected to the first electrode via the first wiring, and a second pad electrode 37 electrically connected to the second electrode via the second wiring. Are provided on the support 31. In addition, although the electric power generation element 3 is provided with only one piezoelectric conversion part 33, it is good not only as this but the structure provided with two or more piezoelectric conversion parts 33. FIG.

  When the power generating element 3 is manufactured by using a MEMS manufacturing technique, it is preferable that the support portion 31 has a rectangular frame shape. That is, it is preferable that the outer peripheral shape of the support part 31 is rectangular. Thereby, the power generating element 3 can improve the workability of the dicing process at the time of manufacture. At the time of manufacturing the power generation element 3, for example, first, a wafer (for example, an SOI wafer) serving as a basis for the support portion 31 and the vibration portion 32 is prepared. At the time of manufacturing the power generation element 3, a pre-process for forming a large number of power generation elements 3 on the wafer is performed, and in a post-process, the individual power generation elements 3 are separated in a dicing process.

  The power generating element 3 is held by the housing 21 such that the front surface 321 of the vibration part 32 is on the inlet 21 side of the housing 2 and the back surface 322 is on the outlet 23 side of the housing 2.

  The power generation element 3 can convert the energy of the fluid passing through the flow path 22 into vibration energy and convert the vibration energy into electric energy.

  In the power generation element 3, since the fluid flowing from the upstream side of the flow path 22 toward the power generation element 3 passes through the gap 35, the flow velocity increases, so the pressure in the space surrounded by the vibration part 32 and the support part 31 decreases. The second end 32 b of the vibration part 32 is displaced in a direction approaching the support part 31. In the power generating element 3, it is estimated that when the pressure difference between the spaces on both sides in the thickness direction of the vibration part 32 disappears, a force that causes the vibration part 32 to return to the original position by the elastic force of the vibration part 32 acts. Is done. In the power generating element 3, it is presumed that the vibration unit 32 self-excites and the piezoelectric conversion unit 33 generates an AC voltage by repeating such an operation. Note that the power generation apparatus 1 of the present embodiment is within the scope of the present invention even if the estimation mechanism is different.

  The power generation device 1 preferably includes a circuit board 7 on which the power generation element 3 is mounted. For example, a printed circuit board can be used as the circuit board 7. The circuit board 7 includes a first conductor portion (not shown) to which the first pad electrode 36 of the power generating element 3 is electrically connected via the first wire. In addition, the circuit board 7 includes a second conductor portion to which the second pad electrode 37 of the power generating element 3 is electrically connected via the second wire. A hole 71 communicating with the flow path 22 is formed in the circuit board 7 so as to penetrate in the thickness direction of the circuit board 7. The circuit board 7 is not limited to the one in which the hole 71 is formed, and may be formed in a U-shape, for example.

  The housing 2 is configured by fixing a first structure 2a in which an inlet 21 is formed and a second structure 2b in which an outlet 23 is formed by two first screws 26 (see FIG. 3). Yes. In the power generation device 1, the power generation element 3 and the circuit board 7 are disposed between the first structure 2 a and the second structure 2 b, and the power generation element 3 and the circuit board 7 are held by the housing 2. The first structure 2a and the second structure 2b are each formed of a resin molded product. Therefore, the power generation device 1 has a higher degree of freedom in the shape of the housing 2 than in the case where the housing 2 is made of metal, and forms the housing 2 having a more complicated shape for suppressing the generation of fluid vortices. It becomes possible. In addition, the power generation device 1 can be reduced in cost compared to the case where the housing 2 is formed of metal.

  The housing 2 is preferably formed in a rectangular parallelepiped shape so that each corner is rounded. In short, it is preferable that the adjacent surfaces of the housing 2 are smoothly continuous. In particular, in the housing 2, it is preferable that the front surface 20a where the entrance is formed and the side surface 20b adjacent to the front surface 20a are smoothly continuous. As a result, the power generation device 1 can suppress the occurrence of vortices or the like in the vicinity of the peripheral portion of the inlet 21 of the housing 2. Therefore, the power generation device 1 can efficiently introduce the fluid into the flow path 22 from the outside of the housing 2. Thereby, the power generation device 1 can apply the fluid to the vibration part 32 of the power generation element 3 more efficiently, and the power generation efficiency can be improved. The power generation device 1 can efficiently generate power with less fluid.

  The fluid introduction part 24 is integrally formed with the first structure 2a. The internal space of the fluid introduction part 24 constitutes a part of the flow path 22. The fluid introduction part 24 is formed in a frame shape in which the opening area gradually decreases as the distance from the inlet 21 approaches the power generation element 3. By providing the fluid introduction unit 24, the power generation device 1 can concentrate the fluid on the power generation element 3 as compared with the case where the opening area of the flow path 22 is uniform. In addition, the power generation device 1 includes the fluid introduction unit 24, so that the flow velocity of the fluid that strikes the power generation element 3 can be increased. Therefore, the power generation device 1 can improve power generation efficiency and power generation voltage.

  The fluid introduction part 24 is formed so as to expose substantially half of the power generating element 3 including the part on the second end 32b side of the vibration part 32b. As a result, the power generation device 1 can easily make the fluid easily hit the second end 32b side of the vibration unit 32, and can improve the power generation efficiency.

  In the power generating element 3, the shape of the support portion 31 is a frame shape, and there is a gap 35 between the outer surface and the inner surface of the support portion 31 over the entire outer surface of the vibration portion 32. Here, the surface area increasing portion 325 is provided on the outer peripheral portion of the second region 321b on the second end 32b side of the surface 321 of the vibration portion 32, which is closer to the second end 32b than the first region 321a where the piezoelectric conversion portion 33 is provided. preferable. Thereby, in the power generation device 1, the fluid that has hit the vibrating portion 32 is less likely to escape, and the power generation efficiency can be improved. Each of the first area 321a and the second area 321b is a rectangular area. The surface area increasing portion 325 can be constituted by, for example, a part of the substrate and a part of the insulating film. Further, the surface area increasing portion 325 can also be configured by a single layer or a multilayer film formed on the insulating film.

  The power storage unit 4 stores the electrical energy generated by the power generation element 3. However, the electrical energy generated by the power generation element 3 is an alternating voltage.

  For this reason, it is preferable that the electric power generating apparatus 1 is a structure provided with the rectifier circuit which rectifies | straightens the alternating voltage generated in the electric power generation element 3, for example. In this case, it is preferable that circuit components of the rectifier circuit are also mounted on the circuit board 7. The power storage unit 4 can be configured by a capacitor, for example. The capacitor which comprises the electrical storage part 4 can be connected between the output terminals of a rectifier circuit, for example. As the rectifier circuit, for example, a full-wave rectifier circuit composed of a diode bridge can be adopted.

  Further, the power generation device 1 is not limited to a configuration including a full-wave rectification circuit as a rectification circuit, and may be configured to include a double-wave voltage doubler rectification circuit as a rectification circuit, for example. The double voltage rectifier circuit can employ a configuration in which a series circuit of two diodes and a series circuit of two capacitors are connected in parallel. In short, the double-wave voltage doubler rectifier circuit can adopt a configuration in which two diodes and two capacitors are bridge-connected. In this case, the power storage unit 4 can be configured by a series circuit of two capacitors of a double wave voltage doubler rectifier circuit.

  The sensor unit 5 includes a temperature sensor that detects temperature as environmental information, a humidity sensor that detects humidity as environmental information, a temperature and humidity sensor that detects temperature and humidity as environmental information, a flow rate sensor that detects flow velocity as environmental information, and the like. Can be adopted. The temperature is the temperature of the fluid. Humidity is the humidity of the fluid. The temperature / humidity is the temperature / humidity of the fluid. The flow rate is the velocity of the fluid.

  The transmission unit 6 is preferably configured by a wireless transmission unit that transmits a wireless signal including environment information detected by the sensor unit 5. Thereby, the electric power generating apparatus 1 becomes high in the freedom degree of an installation place, and can improve versatility. For example, EnOcean (registered trademark), Zigbee (registered trademark), Bluetooth (registered trademark), specific low-power wireless, weak wireless, Wi-Fi (registered trademark), UWB, etc. are adopted as wireless communication standards for the wireless transmitter. can do. The wireless communication standard is not particularly limited.

  As described above, the power generation device 1 is preferably configured such that the sensor unit 5 and the transmission unit 6 operate using the power storage unit 4 as a power source.

  The power generation device 1 preferably includes a switching circuit. The switching circuit is configured to be switchable between a first state in which the power generation element 3 and the power storage unit 4 are electrically connected and a second state in which the power generation element 3 and the sensor unit 5 are electrically connected. Is preferred. Further, the power generation device 1 includes a switching element provided in a power supply path from the power storage unit 4 to the sensor unit 5 and the transmission unit 6 and a monitoring unit that monitors the amount of power stored in the power storage unit 4. preferable. The switching element can be constituted by, for example, a MOSFET or the like. The monitoring unit has a function of monitoring the voltage between the output terminals of the power storage unit 4 as a power storage amount, and turning on and off the switching element based on a comparison result between the power storage amount and a preset specified value. For example, the monitoring unit turns on the switching element when the amount of power stored in the power storage unit 4 reaches the predetermined value set in advance for driving the sensor unit 5 and the transmission unit 6, and switches the switching element when the power storage unit 4 falls below the predetermined value. Turn off the element. Thereby, the sensor unit 5 and the transmission unit 6 are intermittently supplied with power from the power storage unit 4 and driven. The switching circuit can be composed of, for example, one or more switch elements. The monitoring unit can be configured by, for example, an IC element or a microcomputer.

  Since the power generation device 1 includes the switching circuit, it is possible to shorten the time until the amount of power stored in the power storage unit 4 reaches the specified value every time the power storage unit 4 is charged.

  The power generator 1 can be used for an air conditioning management system, for example.

  The air conditioning management system can be configured to include, for example, the power generation device 1 and an air conditioner. The power generation device 1 can be disposed inside an air supply duct (not shown) or an exhaust duct (not shown).

  The air conditioner includes, for example, a fan, a motor that rotates the fan, an operation switch, a control unit that controls the operation state of the fan by controlling the motor, a remote control signal from a remote controller, and the like. And a setting unit for setting the target value. In the air conditioner, when the operation switch is turned on, the control unit drives the motor to rotate the fan. The control unit feedback-controls the rotation speed of the motor so that the flow rate or the flow velocity set by the setting unit becomes a target value. Thus, the air conditioning management system can save energy. The control unit can be configured to include, for example, a control circuit composed of a microcomputer or the like on which an appropriate program is mounted, a drive circuit that drives a motor, and the like.

  The air conditioner includes a receiving unit that receives a radio signal from the transmitting unit 6, and a control unit that controls the operating state of the fan so that the flow rate or flow velocity of the fluid becomes a target value based on the radio signal received by the receiving unit. . Thereby, since the air-conditioning management system includes the power generation device 1 that can reduce power consumption and size, it is possible to reduce power consumption of the entire air-conditioning management system.

  The power generation device 1 is not limited to the above-described embodiment. For example, in the 1st modification of the electric power generating apparatus 1, the electric power generation element 3b of a structure shown to Fig.6 (a) and 6 (b) is employable. The power generation element 3 b is different from the power generation element 3 in that the surface area increasing portion 325 is provided only in a part of the outer peripheral portion in the second region 321 b of the vibration portion 32.

  Moreover, in the 2nd modification of the electric power generating apparatus 1, the electric power generation element 3c of a structure shown to Fig.7 (a) and 7 (b) is employable. The power generating element 3c may be configured to include a plurality of surface area increasing portions 325 on the outer peripheral portion in the second region 321b of the vibrating portion 32.

  Moreover, in the 3rd modification of the electric power generating apparatus 1, the electric power generation element 3 of a structure shown to Fig.8 (a) and 8 (b) is employable. The power generating element 3d may be configured to include a plurality of surface area increasing portions 325 each having a triangular cross section perpendicular to the width direction of the vibration portion 32. The cross section of the surface area increasing portion 325 is not limited to a triangular shape, and may be a hemispherical shape, for example.

  Moreover, in the 4th modification of the electric power generating apparatus 1, the electric power generation element 3e of a structure shown to Fig.9 (a) and 9 (b) is employable. The power generating element 3e is different from the power generating element 3 of the embodiment only in that the surface area increasing portion 325 is configured by a concave portion.

  In the power generation device 1, the power generation element 3 may include a surface area increasing portion 325 including a convex portion and a surface area increasing portion 325 including a concave portion.

  Each figure explained in the above-mentioned embodiment etc. is typical, and the ratio of each size and thickness of each component does not necessarily reflect the actual size ratio.

  The configuration of the present invention has been described above based on the embodiment and the like. However, the present invention is not limited to the configuration of the embodiment, and for example, a configuration in which partial configurations such as the embodiment are appropriately combined. Also good. In addition, the materials, numerical values, and the like described in the embodiments are merely preferable examples, and are not limited thereto. Furthermore, the present invention can be appropriately modified in configuration without departing from the scope of its technical idea.

DESCRIPTION OF SYMBOLS 1 Power generation device 2 Housing 3 Power generation element 4 Power storage part 5 Sensor part 6 Transmission part 21 Inlet 22 Flow path 23 Outlet 31 Support part 32 Vibration part 32a 1st end 32b 2nd end 33 Piezoelectric conversion part 35 Gap 321 Surface 321a 1st area | region 321b 2nd area | region 325 Surface area increase part

Claims (4)

A power generation element and a housing,
The power generation element includes a support portion, a vibration portion, and a piezoelectric conversion portion,
The vibrating portion includes a first end and a second end, the first end is a fixed end fixed to the support portion, and the second end is a free end, and receives fluid energy. Can vibrate,
The piezoelectric conversion unit is configured to overlap with a part of the surface of the vibration unit and generate an alternating voltage by vibration of the vibration unit,
The housing includes a fluid inlet, a fluid outlet, a channel between the inlet and the outlet, and a fluid introduction unit that collects the fluid flowing in from the inlet in the power generation element disposed in the channel. And comprising
The power generating element includes a surface area increasing portion that is configured by a convex portion or a concave portion on the surface of the vibrating portion to increase the surface area of the vibrating portion.
A power generator characterized by that. The power generating element includes a plurality of the surface area increasing portions.
The power generator according to claim 1. In the power generation element, the shape of the support portion is a frame shape, and there is a gap between the outer surface and the inner surface of the support portion over the entire outer surface of the vibration portion,
The surface area increasing portion is provided in an outer peripheral portion in the second region on the second end side of the first region where the piezoelectric conversion portion is provided in the surface of the vibration unit.
The power generator according to claim 1 or 2, characterized by the above. A power storage unit that stores electrical energy generated by the power generation element, a sensor unit that detects at least one environmental information selected from the group of temperature, humidity, and flow velocity, and a transmission that transmits environmental information detected by the sensor unit And comprising
The power storage unit, the sensor unit, and the transmission unit are held in the housing, and the sensor unit and the transmission unit are configured to operate using the power storage unit as a power source.
The power generation device according to claim 1, wherein the power generation device is a power generation device.

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