JP2015186048A - Radio device and radio system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio device that can enhance communication reliability, and a radio system using the same.SOLUTION: A radio system 41 has plural transmitters 21, and a receiver 31 capable of receiving a radio signal from each of the plural transmitters 21, and each of the plural transmitters 21 comprises a radio device 20. The radio device 20 has a power generating device 1, a power storage unit 3, a power supply circuit 4, and a radio module 5. The power generating device 1 converts kinetic energy to electric energy. The power storage unit 3 stores the electric energy generated in the power generating device 1. The power supply circuit 4 supplies power from the power storage unit 3 to the radio module 5 when the voltage V0 between both the ends of the power storage unit 3 exceeds a predetermined value. The radio module 5 has a radio transmitter 6 and a controller 7. The controller 7 is configured to control the radio transmitter 6 so that the same radio signal is continuously wirelessly transmitted at a predetermined number of times from the radio transmitter 6, and has a function of determining a time between the same radio signals to be continuously and wirelessly transmitted.

Description

  The present invention relates to a wireless device and a wireless system using the wireless device, and more particularly to a wireless device including a power generation device that converts kinetic energy into electrical energy and a wireless system using the wireless device.

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

  As an application example of this type of power generation device, a power generation module including a power generation device, a power storage unit that rectifies and stores an AC voltage generated by the power generation device, and a device that is driven by receiving power supply from the power storage unit Has been proposed (Patent Document 1). The power generation device includes a cantilever portion that receives a fluid and self-excites and a piezoelectric conversion portion provided in the cantilever portion. The device includes a detection unit that detects vibration information of the piezoelectric conversion unit, and a wireless transmission unit that transmits a wireless signal including vibration information detected by the detection unit.

  Patent Document 1 describes an air conditioning management system that includes a power generation module and an air conditioner, and the air conditioner includes a wireless reception unit that receives a wireless signal from a wireless transmission unit.

  In the above-described power generation module and air conditioning management system, there is a concern that communication reliability may be reduced due to the influence of noise caused by the installation environment of the power generation module.

International Publication WO2014 / 013638

  An object of the present invention is to provide a wireless device capable of improving communication reliability and a wireless system using the wireless device.

  The wireless device of the present invention includes a power generation device, a power storage unit, a power feeding circuit, and a wireless module. The power generator is configured to convert kinetic energy into electrical energy. The power storage unit is configured to store electrical energy generated by the power generation device. The power feeding circuit is configured to feed power from the power storage unit to the wireless module when a voltage across the power storage unit exceeds a predetermined value. The wireless module includes a wireless transmission unit and a control unit. The control unit is configured to continuously transmit the same radio signal from the radio transmission unit a predetermined number of times, and has a function of determining a time between the same radio signals to be continuously transmitted by radio.

  In this wireless device, it is preferable that the wireless module includes a random number generation unit that generates a random number, and the control unit determines the time based on the random number generated by the random number generation unit.

  In this wireless device, it is preferable that the wireless module includes an address setting unit that sets an address unique to the wireless module, and the control unit determines the time based on an address set by the address setting unit.

  The wireless system of the present invention includes a plurality of transmitters and a receiver capable of receiving wireless signals from each of the plurality of transmitters, and each of the plurality of transmitters includes the wireless device.

  In the wireless device of the present invention, the power feeding circuit is configured to feed power from the power storage unit to the wireless module when the voltage across the power storage unit exceeds a predetermined value. It is possible to reduce the possibility that a radio signal is transmitted. In the wireless device of the present invention, the control unit is configured to continuously transmit the same wireless signal from the wireless transmission unit a predetermined number of times, and between the same wireless signals to be wirelessly transmitted continuously. Since it has a function for determining time, it is possible to further reduce the possibility that radio signals are transmitted simultaneously from different radio apparatuses. Therefore, the wireless device of the present invention can improve communication reliability.

  Since the wireless system of the present invention includes a plurality of transmitters and a receiver capable of receiving wireless signals from each of the plurality of transmitters, each of the plurality of transmitters includes the wireless device. Communication reliability can be improved.

FIG. 1 is a schematic block diagram illustrating a wireless system according to the first embodiment. FIG. 2 is an operation explanatory diagram of the wireless system according to the first embodiment. FIG. 3A is a schematic plan view of the power generation device in the wireless system of the embodiment. 3B is a schematic cross-sectional view taken along the line XX of FIG. 3A. 3C is a schematic cross-sectional view of a main part of FIG. 3A. FIG. 4 is a schematic block diagram illustrating a wireless system according to the second embodiment.

(Embodiment 1)
Below, the radio | wireless system 41 of this embodiment is demonstrated based on FIG.

  The wireless system 41 uses the wireless device 20 as the transmitter 21.

  The wireless device 20 includes a power generation device 1, a power storage unit 3, a power feeding circuit 4, and a wireless module 5. The power generator 1 is configured to convert kinetic energy into electrical energy. The power storage unit 3 is configured to store electrical energy generated in the power generation device 1. The power feeding circuit 4 is configured to feed power from the power storage unit 3 to the wireless module 5 when the voltage V0 across the power storage unit 3 exceeds a predetermined value. The wireless module 5 includes a wireless transmission unit 6 and a control unit 7. The control unit 7 is configured to continuously transmit the same wireless signal from the wireless transmission unit 6 a predetermined number of times, and determines a time T1 (see FIG. 2) between the same wireless signals to be continuously wirelessly transmitted. It has a function. The wireless device 20 is configured such that the power supply circuit 4 supplies power to the wireless module 5 from the power storage unit 3 when the voltage V0 across the power storage unit 3 exceeds a predetermined value. It is possible to reduce the possibility that a radio signal is transmitted. Furthermore, the wireless device 20 is configured such that the control unit 7 wirelessly transmits the same wireless signal from the wireless transmission unit 6 a predetermined number of times, and the time T1 between the same wireless signals to be wirelessly transmitted continuously. Therefore, it is possible to further reduce the possibility that radio signals are transmitted from different radio apparatuses 20 at the same time. Therefore, the wireless device 20 can improve communication reliability.

  The wireless system 41 includes a plurality of transmitters 21 and a receiver 31 that can receive wireless signals from each of the plurality of transmitters 21, and each of the plurality of transmitters 21 includes a wireless device 20. As a result, the wireless system 41 can improve communication reliability.

  Each component of the wireless system 41 will be described in more detail below.

  The power generation device 1 is a piezoelectric vibration power generation device that converts kinetic energy into electrical energy by a piezoelectric effect. The power generation device 1 is formed using a MEMS manufacturing technique.

  As illustrated in FIG. 3, the power generation device 1 includes a support unit 111, a vibration unit 112, and a piezoelectric conversion unit 113. The vibration unit 112 includes a first end 112a and a second end 112b. The vibration part 112 is a fixed end in which the first end 112a is fixed to the support part 111, and the second end 112b is a free end.

  The support 111 has a rectangular frame shape. The vibration part 112 is disposed inside the support part 111 in plan view. Thereby, in the power generation device 1, a gap 115 is formed between the outer side surface of the vibration unit 112 and the inner side surface of the support unit 111.

  The vibration part 112 has a first end 112 a constituted by one end in the length direction of the vibration part 112 and a second end 112 b constituted by the other end in the length direction of the vibration part 112.

  The vibration part 112 is supported by the support part 111 so as to be swingable. The vibration portion 112 is supported by the support portion 111 so as to be swingable because a portion on the first end 112 a side (hereinafter referred to as “beam portion”) is formed thinner than the support portion 111. The vibrating portion 112 preferably includes a weight portion 114 that is thicker than the beam portion on the second end 112b side.

  In the power generation device 1, since the vibration unit 112 includes the weight unit 114, the inertial force at the time of vibration of the vibration unit 112 can be increased and the amplitude of the vibration unit 112 can be increased as compared with the case where the vibration unit 112 is not included. It becomes possible. In addition, since the vibration unit 112 includes the weight part 114, the power generation apparatus 1 concentrates on the portion of the vibration part 112 between the weight part 114 and the support part 111 and the piezoelectric conversion part 113 when the vibration part 112 vibrates. Distortion can be generated. Therefore, the power generation device 1 can improve the piezoelectric conversion efficiency by including the weight portion 114.

  The vibrating portion 112 is warped so that the normal line (not shown) of the distal end surface 112 c does not intersect the support portion 111.

  The piezoelectric conversion unit 113 is provided so as to overlap a part of the surface 121 of the vibration unit 112. The piezoelectric conversion unit 113 generates electrical energy by the vibration of the vibration unit 112. The electrical energy generated by the piezoelectric conversion unit 113 is an alternating voltage. In short, the piezoelectric conversion unit 113 generates an alternating voltage according to the vibration of the vibration unit 112.

The piezoelectric conversion unit 113 includes a first electrode 113a, a piezoelectric layer 113b, and a second electrode 113c in order from the vibration unit 112 side. In short, the piezoelectric conversion unit 113 includes a piezoelectric layer 113b and a first electrode 113a and a second electrode 113c facing each other with the piezoelectric layer 113b sandwiched from both sides in the thickness direction. PZT (Pb (Zr, Ti) O ₃ ) is adopted as the piezoelectric material of the piezoelectric layer 113b.

  In the power generation device 1, the piezoelectric layer 113 b of the piezoelectric conversion unit 113 receives stress due to the vibration of the vibration unit 112, and a charge bias is generated between the second electrode 113 c and the first electrode 113 a, and an AC voltage is generated in the piezoelectric conversion unit 113. Will occur.

  The power generation device 1 includes a first pad electrode 116a electrically connected to the first electrode 113a via the first wiring 117a, and a second electrode electrically connected to the second electrode 113c via the second wiring 117c. A pad electrode 1116 c is provided on the support portion 111.

  The support part 111 and the vibration part 112 are formed from a single substrate 110. The substrate 110 is an SOI substrate in which a silicon layer 110c is formed on an insulating layer 110b made of a silicon oxide film on the silicon substrate 110a.

  In the power generation device 1, the piezoelectric conversion unit 113 is formed on the first surface 101 side of the substrate 110, and the substrate 110 and the piezoelectric conversion unit 113 are electrically insulated between the substrate 110 and the piezoelectric conversion unit 113. A first insulating film 118a is provided. In the power generation device 1, the surface 121 of the vibration unit 112 is configured by a part of the surface of the first insulating film 118a. The first insulating film 118a is composed of a silicon oxide film. This silicon oxide film is formed by a thermal oxidation method. In the power generation device 1, the vibrating portion 112 is warped by the compressive stress of the first insulating film 118 a. In the method for manufacturing the power generation device 1, the internal stress of the first insulating film 118a can be controlled by appropriately setting process conditions such as an oxidation temperature in the step of forming the first insulating film 118a by the thermal oxidation method. The power generation device 1 includes a second insulating film 118 b on the second surface 102 of the substrate 110. The second insulating film 118b is composed of a silicon oxide film. This silicon oxide film is formed by a thermal oxidation method.

The power generation device 1 may have a structure in which a buffer layer is provided between the first insulating film 118a and the first electrode 113a. The buffer layer is a layer provided to improve the crystallinity of the piezoelectric layer 113b on the first electrode 113a. When the piezoelectric material of the piezoelectric layer 113b 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.

  In the power generation device 1, the vibration unit 112 is warped so that the normal line of the distal end surface 112 c of the vibration unit 112 does not intersect the support unit 111 in an initial state where no external vibration, fluid, or the like acts on the vibration unit 112. . Thereby, the electric power generating apparatus 1 can perform fluid excitation vibration. “Fluid excitation vibration” means the vibration of the vibration part 112 generated by the fluid passing through the gap 115. 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. The resonance frequency of the power generation device 1 is determined by the structural parameters, material, and the like of the vibration unit 112.

  In the power generation device 1, the absolute value of the peak value of the AC voltage generated in the piezoelectric conversion unit 113 tends to increase as the fluid flow rate increases.

  In addition, since the vibration unit 112 includes the weight unit 114, the power generation device 1 can reduce the resonance frequency of the vibration unit 112, and can reduce the flow velocity of the fluid at which the vibration unit 112 starts to vibrate. It becomes possible.

  Regarding the estimation mechanism of the operation of the power generation device 1, self-excited vibration occurs due to the force acting on the vibration part 112 when the fluid passes through the gap 115 and the restoring force due to the spring property of the vibration part 112. It is estimated to be. The power generation device 1 is arranged so that the fluid flowing direction and the thickness direction of the substrate 110 coincide with each other, the front surface 121 side of the vibration unit 112 is the upstream side of the fluid, and the back surface 122 side of the vibration unit 112 is the downstream side of the fluid. Are preferably used. In the power generation device 1, the flow velocity increases when the fluid flowing from the upstream side toward the power generation device 1 passes through the gap 115, so that the pressure on the back surface 122 side of the vibration unit 112 decreases and the vibration unit 112 is displaced. Further, in the power generation device 1, the vibration unit 112 is displaced by the force of fluid flowing from the upstream side toward the power generation device 1. And in the electric power generating apparatus 1, when the restoring force of the vibration part 112 becomes larger than the force received from the fluid, it is estimated that the vibration part 112 is displaced in a direction to return to the original position. In the power generation device 1, it is assumed that the vibration unit 112 undergoes self-excited vibration and the piezoelectric conversion unit 113 generates electrical energy by repeating such an operation.

  The power storage unit 3 stores electrical energy generated by the power generation device 1. The radio device 20 includes a rectifier circuit 2 that rectifies the AC voltage generated in the power generation device 1 because the electrical energy generated in the power generation device 1 is an AC voltage, and the power storage unit 3 is connected between the output terminals of the rectification circuit 2. ing. The rectifier circuit 2 is constituted by a full-wave rectifier circuit composed of a diode bridge. The power storage unit 3 is composed of a capacitor.

  The rectifier circuit 2 is not limited to a full-wave rectifier circuit, and may be constituted by, for example, a double-wave voltage doubler rectifier circuit. 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 3 can be configured by a series circuit of two capacitors of a double wave voltage doubler rectifier circuit.

  The power feeding circuit 4 includes a comparator that compares the voltage V0 across the power storage unit 3 with a predetermined value, and a semiconductor switching element that is turned on / off based on the output signal of the comparator. In the power feeding circuit 4, the semiconductor switching element is turned on from off when the voltage V 0 across the power storage unit 3 exceeds a predetermined value, and power is fed from the power storage unit 3 to the wireless module 5. In the power feeding circuit 4, the semiconductor switching element is turned off from on when the voltage V 0 across the power storage unit 3 becomes equal to or lower than a predetermined value. The semiconductor switching element is a MOSFET. The circuit configuration of the power feeding circuit 4 is not particularly limited. For example, a delay circuit or a hysteresis circuit for determining the timing of stopping power feeding may be provided. The predetermined value is set to a value equal to or higher than a voltage necessary for wirelessly transmitting the same wireless signal from the wireless transmission unit 6 a predetermined number of times. The same wireless signal means a wireless signal that is the same wireless signal except for the transmission timing, and includes the same information and pulse width. In FIG. 2, the specified number of times is two, but the specified number may be a plurality of times and may be three or more.

  The wireless module 5 operates using the power storage unit 3 as a power source. Thereby, the radio | wireless apparatus 20 becomes high in the freedom degree of an installation place, and can improve versatility.

  The wireless transmission unit 6 includes a transmission antenna and a transmission circuit that transmits a wireless signal via the transmission antenna.

  The wireless module 5 includes a sensor unit 8. The sensor unit 8 includes a sensor element that detects environmental information. The environmental information is temperature. The environmental information is not limited to temperature, and may be, for example, humidity, temperature / humidity, flow velocity, flow rate, vibration acceleration, gas concentration, and the like.

  The control unit 7 controls the wireless transmission unit 6 so that a wireless signal including environment information detected by the sensor unit 8 is transmitted from the wireless transmission unit 6. The control part 7 can be comprised by the microcomputer etc. which mount an appropriate program, for example.

  Examples of wireless communication standards for the wireless transmission unit 6 include EnOcean (registered trademark), Zigbee (registered trademark), Bluetooth (registered trademark), specific low power wireless, weak wireless, Wi-Fi (registered trademark), UWB, and the like. Can be adopted.

  When the electric energy is generated in the power generation device 1, the wireless device 20 stores the electric energy in the power storage unit 3. When the power supply circuit 4 determines that the voltage V0 across the power storage unit 3 has exceeded a predetermined value, the wireless device 20 is powered from the power storage unit 3 to the wireless module 5 via the power supply circuit 4. Then, the wireless device 20 transmits the same wireless signal from the wireless transmission unit 6 a specified number of times. Thereafter, the wireless device 20 pauses transmission until the voltage V0 across the power storage unit 3 exceeds a predetermined value again. Since the time T2 during which transmission is suspended depends on the amount of electrical energy generated in the power generation apparatus 1, it is possible to reduce the possibility that radio signals are transmitted from different radio apparatuses 20 at the same time.

  In the wireless device 20, the wireless module 5 includes a random number generation unit 9 that generates a random number, and the control unit 7 determines a time T <b> 1 based on the random number generated by the random number generation unit 9. As a result, the radio device 20 can further reduce the possibility that radio signals are transmitted from different radio devices 20 at the same time. Therefore, the wireless system 41 can be configured to include the plurality of transmitters 21 and further improve communication reliability.

  For example, the random number generator 9 randomly generates a numerical value from 1 to 200 as a random number. In this case, the time T1 is randomly set in the range of 1 ms to 200 ms. The control unit 7 associates the random number generated by the random number generation unit 9 with the time T1 on a one-to-one basis. If the random number generated by the random number generation unit 9 is 1, the control unit 7 sets the time T1 to 1 ms. If the random number generated by the random number generation unit 9 is 100, the control unit 7 sets the time T1 to 100 ms. If the generated random number is 200, the time T1 is set to 200 ms. As a method for generating a random number, for example, there are a square center method, a congruence method, a shift register method, and the like. The random number generation unit 9 can be configured, for example, by installing an appropriate program in the microcomputer of the control unit 7. The random number generation unit 9 can be configured by a gate IC, for example.

  The wireless device 20 preferably has its own unique address. In short, it is preferable that the wireless system 41 has a unique address set for each of the plurality of transmitters 21. In this case, it is preferable that the transmitter 21 includes its own address information in the radio signal transmitted by radio from its own radio transmission unit 6.

  The receiver 31 includes, for example, a receiving unit that can receive a radio signal from each radio device 21 and a control unit that controls a device (illustrated) based on the radio signal received by the receiving unit. can do. The receiving unit includes a receiving antenna and a receiving circuit that receives a radio signal via the receiving antenna. The control unit can be configured by, for example, a microcomputer equipped with an appropriate program.

  The transmitter 21 has a configuration including a self-supporting power source configured by the power generation device 1, the rectifier circuit 2, and the power storage unit 3. However, the receiver 31 is commercially available for the entire period during which the wireless system 41 is desired to operate. It is preferable that the external power source such as a power source is always driven with the power source. As a result, the wireless system 41 can receive a wireless signal that does not know when it is transmitted from each transmitter 21.

(Embodiment 2)
Below, the wireless system 42 of this embodiment is demonstrated based on FIG. Note that the wireless system 42 of the present embodiment has substantially the same configuration as the wireless system 41 of the first embodiment, and therefore, the same components as those of the wireless system 41 are denoted by the same reference numerals and description thereof is omitted as appropriate.

  The wireless module 5 in the wireless system 42 includes an address setting unit 10 that sets an address unique to itself, and the control unit 7 determines the time T1 based on the address set by the address setting unit 10. In short, when there are a plurality of wireless devices 20, the time T1 differs for each wireless device 20 depending on the unique address of each of the plurality of wireless devices 20. As a result, the radio device 20 can further reduce the possibility that radio signals are transmitted from different radio devices 20 at the same time. Therefore, the wireless system 41 can be configured to include the plurality of transmitters 21 and further improve communication reliability.

  The address setting unit 10 can be constituted by, for example, a multi-bit dip switch, a digital switch, or the like.

  Each figure explained in the above-mentioned embodiment etc. is a typical figure, and the ratio of each size and thickness of each component does not necessarily reflect an 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, 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 intended to be limited thereto. Furthermore, the present invention can be appropriately modified in configuration without departing from the scope of its technical idea.

  For example, the power generation device 1 is not limited to a configuration that generates power by fluid excitation vibration, but may be configured to generate power using environmental vibration (external vibration) that matches the resonance frequency of the power generation device 1. Examples of the environmental vibration include various vibrations such as vibration generated by an operating FA (factory automation) device, vibration generated by traveling of the vehicle, vibration generated by walking of a person, and the like.

  The power generation device 1 is not limited to the piezoelectric vibration power generation device, and may be, for example, an electromagnetic induction vibration power generation device that converts kinetic energy into electric energy by electromagnetic induction. An electromagnetic induction type vibration power generator generates an alternating current as electric energy.

DESCRIPTION OF SYMBOLS 1 Power generator 3 Power storage part 4 Power feeding circuit 5 Wireless module 6 Wireless transmission part 7 Control part 9 Random number generation part 10 Address setting part 20 Wireless apparatus 21 Transmitter 31 Receiver 41 Wireless system

Claims (4)

A power generation device, a power storage unit, a power feeding circuit, and a wireless module;
The power generator is configured to convert kinetic energy into electrical energy;
The power storage unit is configured to store electrical energy generated in the power generation device,
The power feeding circuit is configured to feed power from the power storage unit to the wireless module when a voltage across the power storage unit exceeds a predetermined value.
The wireless module includes a wireless transmission unit and a control unit,
The control unit is configured to continuously transmit the same wireless signal from the wireless transmission unit a specified number of times, and has a function of determining a time between the same wireless signals to be continuously wirelessly transmitted.
A wireless device characterized by the above. The wireless module includes a random number generator that generates random numbers,
The controller determines the time based on a random number generated by the random number generator;
The wireless device according to claim 1. The wireless module includes an address setting unit that sets an address unique to itself,
The control unit determines the time based on the address set by the address setting unit.
The wireless device according to claim 1. A plurality of transmitters and a receiver capable of receiving radio signals from each of the plurality of transmitters, wherein each of the plurality of transmitters is a radio according to any one of claims 1 to 3. Consisting of equipment,
A wireless system characterized by that.

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