System for a shoe sole, method for operating the system, shoe sole, and shoe

Abstract

To provide a system for a shoe sole having at least one piezoelectric element for generating electrical energy.SOLUTION: In one embodiment, a system for a shoe sole comprises (a.) at least one piezo element adapted to produce an electrical signal upon mechanical deformation of the at least one piezo element, (b.) at least one first energy storage and at least one second energy storage, wherein the at least one first energy storage and the at least one second energy storage are adapted to store electrical energy obtained from the electrical signal, and (c.) at least one converter unit adapted to selectively control a transfer of an amount of electrical energy between the at least one first energy storage and the at least one second energy storage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a system for a shoe sole having at least one piezoelectric element for generating electrical energy. [Background technology]

[0002] Sports are an integral part of daily life. For example, people run to improve fitness and to reduce stress. For this purpose, various digital approaches are known to obtain data of athletes, such as, for example, number of steps, distance traveled, cadence, pace, and speed. In this respect, there are many systems for monitoring a person's athletic performance during or after training, preferably by using integrated sensors (such as, for example, GPS sensors and / or motion sensors) on the person or sports apparel (such as, for example, shoes). The measured parameters during or after the practice can then be transferred to a monitoring device (such as, for example, a smartphone). Moreover, sports apparel or sports equipment (such as, for example, sports shoes) can also include other electronic devices (such as, for example, lighting, powering actuators, temperature regulation, safety features, and adaptation of properties).

[0003] These sensors and electronic devices typically require an energy supply, such as a battery, which, if depleted and needs to be replaced, can result in important data being lost or the respective device no longer functioning.

[0004] One example of the other sensor or electronic device includes a piezoelectric element for generating or harvesting electrical energy during exercise performance, which is then coupled to the respective sensor and Overall System The signal may be stored or used to operate the

[0005] The applicant discloses in EP 3235395 A1 a system for a shoe sole having at least one module, the module including at least one piezoelectric element, the at least one piezoelectric element being adapted to create an electric signal when a mechanical deformation of the at least one piezoelectric element occurs. The electric signal is adapted to be used as a signal for deriving at least one motion parameter of the shoe sole. The system further includes at least a first energy store and a second energy store, the at least first and second energy stores being adapted to store an electric energy obtained from the electric signal, the second energy store being loaded only after the first energy store reaches a first energy threshold.

[0006] Further prior art is disclosed in U.S. Patent Application Publication No. 2013 / 0028368A1, U.S. Patent Application Publication No. 2014 / 0088917A1, and Ishida et al., "Insole Pedometer With Piezoelectric Energy Harvester and 2V Organic Circuits."

[0007] However, a common disadvantage of the prior art is that known systems rely on pre-stored input voltages that correspond to specific mechanical deformations of the shoe. For example, two athletes of different weights running at different speeds on different surfaces will generate different input voltages to the piezoelectric element, and the system may no longer function or function efficiently.

[0008] SUMMARY OF THE PRESENT EMBODIMENT It is therefore an object underlying the present invention to overcome the above-mentioned disadvantages of the prior art and to provide an improved shoe sole having a piezoelectric element for harvesting electrical energy. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] European Patent Application Publication No. 3235395A1 [Patent Document 2] US Patent Application Publication No. 2013 / 0028368A1 [Patent Document 3] US Patent Application Publication No. 2014 / 0088917A1 [Non-patent literature]

[0010] [Non-Patent Document 1] "Insole Pedometer With Piezoelectric Energy Harvester and 2V Organic Circuits" by Ishida et al. Summary of the Invention

[0011] This object is achieved by the teaching of the independent claims. Advantageous embodiments are contained in the dependent claims.

[0012] In one embodiment, a system for a shoe sole includes: (a.) at least one piezoelectric element adapted to produce an electrical signal when a mechanical deformation of the at least one piezoelectric element occurs; (b.) at least one first energy storage unit and at least one second energy storage unit adapted to store electrical energy obtained from the electrical signal; and (c.) at least one converter unit adapted to selectively control a transfer of an amount of electrical energy between the at least one first energy storage unit and the at least one second energy storage unit.

[0013] Whereas the prior art systems are limited to a specific input voltage of the piezoelectric element in the shoe sole, the present invention follows an improved approach by providing at least one converter unit that uses the effect of power conversion. This process involves the conversion (or transformation) of electrical energy from one form to another (e.g., change in voltage, etc.). For this purpose, the at least one converter unit allows selectively controlling the change in voltage (e.g., capacitance) applied to the first energy storage unit, so that different amounts of electrical energy generated from the mechanical deformation of the piezoelectric element can be transferred to the second energy storage unit. In this way, an improved system can be provided, which can adapt to different input voltages from the piezoelectric element and the amount of energy consumed by its components (e.g., sensors or electronic devices, etc.). The entire system can therefore operate more efficiently due to the adapted transfer of voltages.

[0014] The terms "voltage", "energy", "power", "charge", and "current" as used in this application refer to the well-known equations for capacitance, electrical energy, and power in an electric circuit: C=Q / V, where C is capacitance, Q is charge, and V is voltage; W=0.5*C*V 2 (where W is electrical energy, C is capacitance, and V is voltage); and it should be noted that P can be related by P=V*I (where P is power, V is voltage, and I is current).

[0015] Moreover, the terms "piezo" and "piezoelectric" as used in this application may be interchangeable. The same applies to the terms "electric" and "electrical". Moreover, it should be noted that the control of the transfer of a certain amount of electric energy by the at least one converter unit is in a selective manner following some regular (or calculable) pattern having a certain periodicity. Simple (irregular) switching on and off of the at least one converter unit by a human being should not be indicative of selective control according to the present invention.

[0016] At least one converter unit may be adapted to selectively control the transfer of an amount of electrical energy based at least in part on a switching frequency. The switching frequency may correspond to a switch between a charging state and a discharging state of the at least one converter unit. In this manner, the inventors have found that using oscillations between a charging state and a discharging state of a converter unit having a particular switching frequency allows for precise control of the amount of charge (and thus the amount of electrical energy) to be transferred, so that selective control by the converter units may be optimized. For example, at a higher switching frequency, more charge may be transferred in the same amount of time, since the charging state occurs more frequently.

[0017] The switching frequency is a frequency that is proportional to the electrical signal of at least one piezoelectric element and / or the frequency of the switching ... AllThe energy storage device may be based at least in part on the power of the system. This embodiment further allows for better control of the transfer of electrical energy between the two energy storages. Thus, better adaptability between different input voltages and the power required by the system may be provided. In one example, when two capacitors are used as the first and second energy storages, the capacitance of each capacitor may be as follows: the first capacitor may have a capacitance in the range of 15 μF to 30 μF, and the second capacitor may have a capacitance in the range of 100 μF to 150 μF, so that an optimized amount of electrical energy required for the parts of the system operating may be determined.

[0018] The system may further include a control unit adapted to calculate the switching frequency. For example, the control unit may be a microcontroller, a programmable logic, or an integrated circuit, or another suitable electrical component, that is part of the system, which may allow to calculate or determine an optimal switching frequency depending on the input voltage generated by the piezoelectric element and the power used by the system. Alternatively, other controllers for remote transmission may be used (e.g., Bluetooth Low Energy (BTLE), Bluetooth, Bluetooth Smart, IrDA, Near Field Communication (NFC), cellular networks, ZigBee, Wifi, or other controllers using suitable standards) and may allow to calculate an optimal switching frequency depending on the input voltage generated by the piezoelectric element and the power used by the system.

[0019] The charging state may have a duration in the range of 20ns to 180ns, preferably in the range of 50ns to 150ns, more preferably in the range of 80ns to 120ns, most preferably in the range of about 100ns or 200ns to 400ns, preferably in the range of 250ns to 350ns, more preferably in the range of 275ns to 325ns or in the range of 225ns to 275ns, most preferably about 300ns. Such duration may be recognized as a pulse duration of the charging time during the charging state of at least one converter unit. Together with the switching frequency (corresponding to the number of these pulses) the total amount of electrical energy to be transferred may be determined. It has been found that these numbers for the duration provide a reasonable compromise between a sufficient amount of electrical energy to be transferred during the charging state and a reliable operation of the entire system. In this context and also below the term "about" refers to typical measurement tolerances in the technical field of the invention.

[0020] The at least one converter unit may have an active mode and an inactive mode, and a transition between the active mode and the inactive mode may be based at least in part on a lower threshold and / or an upper threshold for the electrical energy measured in the at least one first energy store, and selective control of the at least one converter unit may be provided only in the active mode. In this way, unnecessary energy consumption of the converter unit may be avoided. It allows the converter unit to start its selective control only when a sufficient electrical energy level in the energy store is provided, and the excess energy provided by the piezo element may be transferred and stored.

[0021] The at least one converter unit may be a flyback converter having a primary transformer side connected to the at least one first energy storage and a secondary transformer side connected to the at least one second energy storage, wherein electrical energy may be transferred from the at least one first energy storage to the at least one converter unit in a charging state and electrical energy is transferred from the at least one converter unit to the at least one second energy storage in a discharging state.

[0022] The flyback converter may be used as a transformer for direct current (DC) conversion (i.e., DC / DC conversion) with galvanic isolation between the input and any output. For this purpose, the conversion or change of voltage may be provided in a safe and reliable manner. Moreover, the electrical components may be easily adapted to the above-mentioned switching frequency and its calculation. For example, when the flyback converter is in a charging state, electrical energy is loaded from a first energy storage (e.g., an input capacitor) to the primary transformer side for the duration of the charging state. As soon as the flyback converter switches to a discharging state, electrical energy is transferred from the primary transformer side to the secondary transformer side of the flyback converter and thus to a second energy storage (e.g., an output capacitor).

[0023] The at least one converter unit may include a metal oxide semiconductor field effect transistor (MOSFET) switch adapted to switch the at least one converter unit between a charging state and a discharging state. This component may provide certain advantages: higher efficiency while operating at a lower voltage; the lack of gate current results in a high input impedance creating a high switching frequency; and it operates at a lower power and does not draw current (or charge).

[0024] The system may further include a power management unit adapted to generate a control signal for switching at least one converter unit between a charging state and a discharging state. Such a component may control or instruct the above-mentioned control unit in a reliable manner to further control the switching of the converter unit.

[0025] The system may further include at least one third energy storage unit adapted to store electrical energy obtained from the electrical signal and to provide electrical energy to the at least one second energy storage unit when the electrical signal from the at least one piezoelectric element falls below a piezo threshold of the electrical energy.

[0026] The capacity of the third energy storage unit can be larger than the capacity of the first and second energy storage units, so that when the athlete has to rest for a short time or even after the activity, data can be transferred from the system to an external and remote device (such as a smartphone, a smartwatch, a tablet computer, a personal computer, or another device). This is advantageous because it can be ensured that the time required to prepare the system can be reduced by using the first energy storage unit without risking that the electrical energy is used for other less necessary aspects (such as data transmission to a remote device and operation of LEDs) in the meantime. Therefore, it is better to have a separately controllable energy storage unit (for example, when the electrical signal from at least one piezo element falls below the piezo threshold of the electrical energy). The type of the third capacitor can be a supercapacitor, a thin-film lithium battery, or the like. The leakage current in the third energy storage unit should be as small as possible to maintain the charge over several hours / days. For example, this can be achieved by appropriate selection of the first and second storage units (e.g., capacitors). For example, some capacitors can have lower leakage than other capacitors. In one example, the third energy storage unit may be charged at the factory during the manufacturing process. However, alternatively or additionally, it may be charged during use. In one example, the third energy storage unit is loaded only after the second energy storage unit reaches a threshold voltage.

[0027] The system may further include at least one regulator unit, preferably a Junction Field Effect Transistor (JFET) regulator, adapted to switch between a regulated mode and a non-regulated mode of the at least one regulator unit based at least in part on a regulation threshold of the electrical energy. Moreover, the regulated mode may cause the at least one second energy storage to remain in a regulated voltage range between 1.0V and 4.0V, preferably between 1.5V and 3.5V, more preferably between 2.0V and 3.0V, or between 2.0V and 5.5V, or between 3.0V and 4.2V, so that electrical energy accumulates in the at least one first energy storage and / or preferably the control unit and the power management unit operate in this regulated voltage range. Thus, Overall System A better energy supply for and improved control of the converter unit can be provided by the regulated mode. Moreover, the values ​​shown have been found to optimize this mode. Above all, the JFET can be useful because it has a high input impedance, can be fabricated in a small size area, has less noise in the electric circuit, has low power consumption, has a negative temperature coefficient of resistance, and therefore can provide a higher temperature stability. Moreover, the JFET can also help the system start up from an empty energy store or from a complete shutdown. Because the power management unit has no voltage, the second energy store can be charged by the J-FET, and when the power management unit is turned on, the J-FET can be cut off, so that a more efficient converter unit can take over and transfer energy from the first energy store to the second energy store.

[0028] The system may further comprise at least one comparator unit adapted to measure a regulation threshold of the electrical energy. In this way, a more stable operation of the above-mentioned regulation mode may be provided by this further component.

[0029] Moreover, the system may further include at least one rectifying unit adapted to convert the electric signal. The electric (current) signal from the piezoelectric element is an alternating current (AC) resulting from different mechanical deformations (e.g., mechanical strain is exerted on the piezoelectric element and released). The rectifying unit may convert the AC current into a DC current, which may further be provided to the energy storage. As a result, the rectifying unit may enable better use of the electric current (and thus the electric energy) from the piezoelectric element for different mechanical deformations.

[0030] The system may further include at least one of the following components: a signal processing unit, a first comparator unit, a second comparator unit, a first switching unit, a second switching unit, a third switching unit, or a battery unit. Moreover, the system may include at least one of the following arrangements: at least one piezo element is connected to the signal processing unit; at least one rectifier unit is connected between the at least one piezo element and the at least one first energy storage unit; the at least one first energy storage unit is connected to at least one of the at least one regulator unit, the at least one converter unit, or the power management unit; the at least one regulator unit is connected between the at least one first energy storage unit and the at least one second energy storage unit and is connected to the first comparator unit; the at least one converter unit is connected to at least one of the at least one first energy storage unit, the at least one second energy storage unit, or the power management unit; the at least one second energy storage unit is connected to the at least one comparator unit. The energy storage is connected to at least one of the at least one third energy storage, the first comparator unit, or the second comparator unit, preferably connected to the at least one third energy storage by a first switching unit; the first comparator unit is connected to the first switching unit; the at least one third energy storage is connected to at least one of the battery unit, the control unit, and the power management unit, preferably connected to the battery unit by a second switching unit, and preferably connected to the control unit by a third switching unit; the control unit is connected to the power management unit; and the power management unit is connected to at least one of the signal processing unit, the second switching unit, or the third switching unit. All these embodiments are in accordance with the present invention. Overall System The idea is to optimize the energy storage and consumption of the battery.

[0031] The system may be integrated into a cavity of the insole, midsole, or outsole of the shoe. Here, one or more parts of the system may be integrated into different parts of the shoe or shoe sole depending on one or more of the athlete's use, situation, or sport (e.g., trail running or playing soccer), so that reliable operation of the system may be obtained. For example, running shoes have thicker midsoles, so that there is more space to integrate the system, while soccer shoes do not have midsoles, so that the system (or part of it) must be integrated into the insole and / or outsole.

[0032] At least two piezo elements may be arranged in the heel area and / or the forefoot area of ​​the shoe sole. During the respective use of the shoe and the shoe sole, there may be some parts of the shoe sole with more mechanical deformation (e.g., (vertical) pressure on the shoe sole or bending of the shoe sole). For example, the heel area and / or the forefoot area may be subjected to higher pressure than the midfoot area. Moreover, the forefoot area may be subjected to higher bending than other areas of the shoe sole. Thus, the areas with higher pressure or higher bending may depend on the specific activity, for example, it may make a difference whether the wearer plays soccer, which requires long sprints, or basketball, which requires quick lateral movements. Therefore, by installing multiple piezo elements in certain areas of the shoe sole and by taking these aspects into account, Overall System energy efficiency improvements can be obtained.

[0033] Another aspect of the invention relates to a shoe sole comprising one of the above-mentioned embodiments of the system according to the invention. Yet another aspect of the invention relates to a shoe, in particular a sports shoe, comprising this shoe sole. The same advantages as those mentioned for the system also apply here.

[0034] Yet another aspect of the invention relates to a method for operating a system as described above, the method including: (a.) generating an electrical signal when mechanical deformation of at least one piezo element occurs; and (b.) selectively controlling a transfer of an amount of electrical energy between at least one first energy storage unit and at least one second energy storage unit. The selectively controlling step may include switching at least one converter unit between a charging state and a discharging state by using a switching frequency, where electrical energy is transferred from the at least one first energy storage unit to the at least one converter unit in the charging state, and electrical energy is transferred from the at least one converter unit to the at least one second energy storage unit in the discharging state. The method may further include calculating a switching frequency. The method may further include switching the system between an active mode and an inactive mode, and / or between a regulated mode and an unregulated mode. Here, the same advantages as described with respect to the system apply analogously.

[0035] In the following, exemplary embodiments of the invention are described with reference to the figures. [Brief description of the drawings]

[0036] [Figure 1] 1 is an exemplary schematic diagram of a system for a shoe sole according to the present invention. [Figure 2A] FIG. 2 shows a circuit diagram of a converter unit in a system for a shoe sole according to the present invention. [Figure 2B]4A-4D are diagrams illustrating the operation of a converter unit in a system for a shoe sole according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] In the following, some embodiments of the present invention are described in detail with particular reference to a system for a shoe sole including at least one piezoelectric element and other electronic components (such as an energy storage unit and at least one converter unit, etc.). However, the concept of the present invention is equally or similarly applicable to other parts of a shoe, such as a shoe upper, capable of generating and storing electrical energy from the mechanical deformation of a piezoelectric element. Moreover, this concept may be applied identically or similarly to any sports equipment or functional sportswear with sufficient mechanical deformation for the piezoelectric body (e.g., balls (e.g., for soccer, rugby, American football, basketball, baseball, etc.), or for example, shirts, clothes, socks, underwear, etc.), or to sports equipment (e.g., tennis rackets, golf clubs, baseball bats, badminton rackets, cricket bats, ice hockey sticks, hockey sticks, ice skating blades, sled attachments, jump attachments, attachments with wheels, attachments with springs, fin-like attachments, attachments enabling hovering, flying, squash rackets, table tennis bats, boxing gloves, skis, snowboards, kites, etc.).

[0038] It will be understood that these exemplary embodiments may be modified in several ways and combined with one another whenever compatible, and that certain features may be omitted insofar as they are deemed unnecessary.

[0039] The terms "voltage", "energy", "power", "charge" and "current" as used in this application refer to the well-known equations for capacitance, electrical energy and power in an electric circuit: C=Q / V, where C is capacitance, Q is charge and V is voltage; W=0.5*C*V 2 (where W is electrical energy, C is capacitance, and V is voltage); and it should be noted that P can be connected by P=V*I (where P is power, V is voltage, and I is current).

[0040] Moreover, as used in this application, the terms "piezo" and "piezoelectric" may be interchangeable, as may the terms "electrical" and "electrical."

[0041] 1 shows an exemplary schematic diagram of a system 100 for a shoe sole including a piezo element 105 (e.g., a piezo generator) according to the present invention. In the following, the operation of the system 100 will be explained in more detail.

[0042] Initially, the system 100 is empty of charge / current / voltage, no electrical energy is stored, and units (or electrical components) requiring electrical energy are set to OFF.

[0043] As mentioned above, the piezoelectric element 105 (e.g., a piezogenerator) generates an electrical signal or current as a result of mechanical deformation, although it is noted that other types of elements capable of generating an electrical current from mechanical strain may also be used to realize the present invention.

[0044] Information about the current (or input voltage) generated at the piezoelectric element 105 may be obtained by the signal processing unit 107 and subsequently provided to a power management unit 110 (eg, control logic).

[0045] The current from the piezo element 105 is then conveyed to a rectifier unit 112, which converts the alternating current (AC) signal of the piezo element 105 into a direct current (DC) signal.

[0046] Moreover, it is pointed out that various sensors may be used in connection with the system 100. For example, any one or combination of accelerometers, gyroscopes, magnetometers, pressure sensors, and position sensors may be used with the system 100. In one example, these sensors may be controlled by a power management unit 110, which is adapted to control the rest of the system 100, and the sensors are capable of obtaining the electrical energy required to operate them from an energy storage unit as described herein. Thus, the autonomous system 100 having one or more sensors (e.g., accelerometers, gyroscopes, magnetometers, and / or position sensors) (the generated electrical energy is used as both a sensor signal and energy to operate the system 100) may also be realized by other types of elements (e.g., electromagnetic type including a body with permanent magnetization configured to move in a coil (the movement is generated by exerting pressure on the element)).

[0047] A first energy storage unit 115 (e.g., a first capacitor) is initially loaded with an electrical signal, causing a corresponding voltage rise in the first capacitor (V=Q / C), where C is capacitance, Q is charge, and V is voltage.

[0048] The current then passes through regulator unit 120, which is preferably a junction field effect transistor (JFET) regulator. At the beginning of operation, regulator unit 120 is in an unregulated mode, so that the current flows directly into second energy storage 125 (e.g., a second capacitor).

[0049] When the voltage in the second energy storage 125 exceeds a certain voltage level, the first comparator unit 130 controls the first switching unit 135 so that a current is conducted into the third energy storage 140 (e.g., a third capacitor). At the same time, the power management unit 110 is powered and set to ON.

[0050] The voltage level detection method of the first comparator unit 130 may be used by a resistor bridge, which is in series with a load switch component, which is connected to a capacitor. A direct voltage measurement method may also be used.

[0051] The first energy storage unit 115, the second energy storage unit 125, and the third energy storage unit 140 can be a capacitor, a supercapacitor, a thin-film lithium battery, or other types of suitable energy storage units (e.g., any battery). Of course, various combinations of any of these types can be used. For example, the first energy storage unit 115 can be a capacitor and the second energy storage unit 125 can be a thin-film lithium battery. In this way, the different characteristics and advantages of each type of energy storage unit can be optimally used. As an example, a first type of energy storage unit can be charged quickly but cannot hold stored energy for a longer period of time. Another energy storage unit may require a longer time to charge but may be able to store energy for a longer period of time.

[0052] If the voltage in the second energy storage 125 exceeds the regulation threshold of the electrical energy measured by the second comparator unit 147, the regulator unit 120 switches to the regulation mode, so that the second energy storage 125 and / or the third energy storage 140 can stay within a regulated voltage range between 1.0V and 4.0V, preferably between 1.5V and 3.5V, more preferably between 2.0V and 3.0V. In this regulated voltage range, the voltage in the first energy storage 115 can rise and electrical energy can be stored (W=0.5*C*V 2 ), where W is the electrical energy, C is the capacitance, and V is the voltage.

[0053] As soon as the voltage in the first energy storage unit 115 exceeds the upper converter threshold, the converter unit 150 (e.g., a flyback converter as will be described later) enters from an inactive mode into an active mode and selectively controls the transfer of an amount of electrical energy between the first energy storage unit 115 and the second energy storage unit 125.

[0054] In the active mode, the converter unit 120 transfers charge (or electrical energy) from the first energy storage unit 115 to the second energy storage unit 125 by power conversion as described above. In this way, selective control between the first energy storage unit 115 and the second energy storage unit 125 according to convention can be obtained.

[0055] This transfer of electrical energy occurs at a certain (switching) frequency that causes the converter unit 120 to switch between a charging state and a discharging state (as will be explained later with respect to FIGS. 2A and 2B). The switching of this converter unit 150 can be adapted so that the amount of charge (and thus the amount of electrical energy) to be transferred can be selectively controlled. At a higher switching frequency, more charge can be transferred in the same amount of time during the active mode, because the charging state can occur more frequently.

[0056] The active or inactive mode of the converter unit 150 is based on the input voltage of the first energy storage 125 from the piezoelectric element 110 (i.e., the upper converter threshold and the lower converter threshold). In one example, the power management unit 110 can check the voltage level in the first energy storage 125 every 200 ms. Depending on the specific characteristics, other time intervals for checking the voltage level may also be applicable, such as every 50 ms, every 100 ms, every 300 ms, or every 500 ms, etc.

[0057] When in active mode, the power management unit 110 generates and sends control (switching) signals to the converter unit 150. The control (switching) signals manage the charging and discharging states of the converter unit by using Metal Oxide Semiconductor Field Effect Transistor (MOSFET) switches (not shown). Other FET-based switches are also contemplated.

[0058] When the converter unit 150 (e.g., a flyback converter) is in a charging state (e.g., the MOSFET switch is conducting), electrical energy is loaded from the first energy storage 115 to the primary transformer side of the flyback converter 150. The duration of the charging state can be defined in the power management unit 110 (e.g., in the range of 20ns to 180ns, preferably in the range of 50ns to 150ns, more preferably in the range of 80ns to 120ns, most preferably in the range of about 100ns or 200ns to 400ns, preferably in the range of 250ns to 350ns, more preferably in the range of 275ns to 325ns or in the range of 225ns to 275ns, most preferably in the range of about 300ns).

[0059] As soon as the converter unit 150 switches to a discharging state (e.g. the MOSFET switch is not conducting), electrical energy is transferred from the primary transformer side into the secondary transformer side of the converter unit 150 and then to the second energy storage 125. These charge-discharge-switches can be scheduled periodically while the converter unit 150 is in active mode and can be subject to selective control by the present application. The frequency of this scheduling is the switching frequency mentioned above and can be adapted by the power management unit 110 as explained above.

[0060] When charge (or electrical energy) is transferred into the primary transformer side of the converter unit 150, the voltage in the first energy storage 115 will drop. As soon as the voltage in the first energy storage 115 falls below the lower converter threshold, the converter unit 150 will enter an inactive mode and the power management unit 110 can stop the above-mentioned control signal switching.

[0061] The duration of the converter unit 150 in active mode can be measured and used to adjust the switching frequency, where the optimal switching frequency is determined by the piezoelectric element. 105 and / or used by the system 100. All It is noted that the optimal switching frequency may depend on the power. Thus, the optimal switching frequency can be either determined by calculations in the control unit 155 (e.g., a microcontroller) and / or by calculations in the power management unit 110. Once determined, this switching frequency can be used in the power management unit 110 to switch the charging and discharging states of the converter unit 150. Thus, the converter unit 150 can operate in an optimal mode.

[0062] The power management unit 110 may cause at least one of the second switching unit 160 and / or the third switching unit 170 to switch on, the supercapacitor storage 165 and / or the control unit 155 to power up when a certain voltage level is sufficient.

[0063] When the electrical signal from the piezo element 110 is too little or is stopped, the second energy store 125 and / or the third energy store 140 may be supplied from the supercapacitor store 165 (or a battery).

[0064] In addition, the electrical energy from the third energy storage unit 140 can also be used for other purposes, such as fast start-up of the system 100. In this way, the system 100 is capable of managing itself based on the self-harvested energy. Nevertheless, the system 100 can be designed to have very low power consumption.

[0065] The energy storage mentioned above can be one or more of a capacitor, a supercapacitor, a thin-film lithium battery, or other suitable types of energy storage (e.g., any battery) with lower power leakage and small dimensions. The firmware of the control unit 155 can be designed in a way that it goes into a sleep mode when not in use. This allows for lower power consumption and more efficient energy usage.

[0066] 2A and 2B illustrate the circuitry and operation of a converter unit in a system for a shoe sole according to the present invention (eg, converter unit 150 in system 100 as described with respect to FIG. 1).

[0067] Figure 2A shows an exemplary circuit diagram of a converter unit, which is a flyback converter 200 in active mode, similar to the converter unit 150 in Figure 1. In the following, the operation of the flyback converter 200 in active mode will be explained in more detail.

[0068] As stated, the flyback converter 200 as a transformer 205 may be used for direct current conversion, DC / DC conversion, with galvanic isolation between an input voltage 210 (e.g., from a piezoelectric element (not shown, but similar to piezoelectric element 110)) and an output voltage 230. The input voltage 210 (and corresponding electrical energy) is applied to a first capacitor 215 (similar to first energy storage 115), and the output voltage 230 (and corresponding electrical energy) is applied to a second capacitor 235 (similar to second energy storage 125).

[0069] When in an active mode, the power management unit (similar to the power management unit 110) generates and sends a control (switching) signal 240 to the flyback converter 200 by using a metal oxide semiconductor field effect transistor (MOSFET) switch 247. As stated, the control (switching) signal 240, together with the MOSFET switch 247, can manage the charge and discharge states of the flyback converter 200 for selective control of the transfer of an amount of electrical energy between the first capacitor 215 and the second capacitor 235.

[0070] When the MOSFET switch 247 is conducting, the flyback converter 200 is in a charging state. Electrical energy is then loaded from the first capacitor 215 to the primary transformer side 242 of the flyback converter 200. The duration of the charging state can be defined in the power management unit as described above (e.g., in the range of 20ns to 180ns, preferably in the range of 50ns to 150ns, more preferably in the range of 80ns to 120ns, most preferably in the range of about 100ns or 200ns to 400ns, preferably in the range of 250ns to 350ns, more preferably in the range of 275ns to 325ns or 225ns to 275ns).

[0071] When the MOSFET switch 247 is not conducting, the flyback converter 200 is in a discharging state. Electrical energy is then transferred from the primary transformer side 242 to the secondary transformer side 245 of the flyback converter 200.

[0072] This electrical energy is further transferred via a rectifier unit 250 (e.g., a rectifier diode) to the second capacitor 235. The transitions (or switches) between the charging and discharging states of the flyback converter 200 may be periodically scheduled by the aforementioned switching frequency applied by the combination of the power management unit and the MOSFET switch 247.

[0073] 2B illustrates different modes and states of the flyback converter 200 that change over time (from left to right) and as a function of the input voltage 210 (e.g., from a piezo element (not shown, but similar to piezo element 110)). The active mode 255 or inactive mode 265 of the flyback converter 200 is based on two specific input voltages 210 on the first capacitor 215: a lower converter threshold 270 (for the inactive mode 265) and an upper converter threshold 275 (for the active mode 255).

[0074] When the input voltage 210 on the first capacitor 215 exceeds the upper converter threshold 275, the flyback converter 200 will enter the active mode 255, as described above.

[0075] During this mode, the flyback converter 200 switches between a charging state 285 and a discharging state 290 at a switching frequency 280 .

[0076] In the charging state 285, electrical energy is loaded from the first capacitor 215 to the primary transformer side 242 of the flyback converter 200. When in the discharging state 290, electrical energy is then transferred from the primary transformer side 242 to the secondary transformer side 245 of the flyback converter 200.

[0077] The duration of a charge state 285 may be known as a pulse duration of charge time. In Figure 2B, there are four individual (energy or charge) pulses between the four charge states 285. With a higher switching frequency 280, more pulses (or charge states 285) can occur in the active mode 255, so that more total charge (and, consequently, a higher amount of electrical energy) can be transferred in the same amount of time.

[0078] When the input voltage 210 at the first capacitor 215 drops below the lower converter threshold 270, the flyback converter 200 enters the inactive mode 265 and stops switching between the charging state 285 and the discharging state 290.

[0079] As soon as the input voltage 210 on the first capacitor 215 exceeds the upper converter threshold 275 again, the flyback converter 200 will return to the active mode 255 and will continue to switch between the charging state 285 and the discharging state 290. The present invention includes the following inventions. [Invention 1] A system (100) for a shoe sole, comprising: a. at least one piezo element (105) adapted to produce an electrical signal (210) upon mechanical deformation of the at least one piezo element (105); b. at least one first energy storage unit (115, 215) and at least one second energy storage unit (125, 235), adapted to store electrical energy obtained from said electrical signal (210); c. at least one converter unit (150, 200) adapted to selectively control a transfer of an amount of electrical energy between said at least one first energy storage unit (115, 215) and said at least one second energy storage unit; The system (100) includes: [Invention 2] The system (100) of invention 1, wherein the at least one converter unit (150, 200) is adapted to selectively control the transfer of an amount of electrical energy based at least in part on a switching frequency (280) between a charging state (285) and a discharging state (290) of the at least one converter unit (150, 200). [Invention 3] The system (100) of invention 2, wherein the switching frequency (280) is based at least in part on the electrical signal (210) of the at least one piezoelectric element (105) and / or the overall power used by the system (100). [Invention 4] 4. The system (100) according to claim 2 or 3, further comprising a control unit (155) adapted to calculate said switching frequency (280). [Invention 5] The system (100) according to any one of claims 2 to 4, wherein the charged state (285) has a duration in the range of 20ns to 180ns, preferably in the range of 50ns to 150ns, more preferably in the range of 80ns to 120ns, most preferably in the range of about 100ns or 200ns to 400ns, preferably in the range of 250ns to 350ns, more preferably in the range of 275ns to 325ns or 225ns to 275ns, most preferably about 300ns. [Invention 6] The system (100) according to any one of claims 1 to 5, wherein the at least one converter unit (150, 200) has an active mode (255) and an inactive mode (265), the transition between the active mode (255) and the inactive mode (265) being based at least in part on a lower converter threshold (270) and / or an upper converter threshold (275) for the electrical energy measured in the at least one first energy storage unit (115, 215), and the selective control of the at least one converter unit (150, 200) is provided only in the active mode (255). [Invention 7] The system (100) according to any one of claims 1 to 6, wherein the at least one converter unit (150, 200) is a flyback converter (200), the flyback converter (200) having a primary transformer side (242) connected to the at least one first energy storage unit (115, 215) and a secondary transformer side (245) connected to the at least one second energy storage unit (125, 235). [Invention 8] The system (100) according to any one of claims 2 to 7, wherein in the charging state (285), the electrical energy is transferred from the at least one first energy storage unit (115, 215) to the at least one converter unit (150, 200), and in the discharging state (290), the electrical energy is transferred from the at least one converter unit (150, 200) to the at least one second energy storage unit (125, 235). [Invention 9] The system (100) according to any one of claims 2 to 8, wherein the at least one converter unit (150, 200) comprises a metal oxide semiconductor field effect transistor (MOSFET) switch (247) adapted to switch the at least one converter unit (150, 200) between the charging state (285) and the discharging state (290). [Invention 10] The system (100) according to any one of claims 2 to 9, further comprising a power management unit (110) adapted to generate a control signal (240) for switching said at least one converter unit (150, 200) between said charging state (285) and said discharging state (290). [Invention 11] The system (100) according to any one of claims 1 to 10, further comprising at least one third energy storage unit (140) adapted to store electrical energy obtained from said electrical signal (210) and to provide electrical energy to said at least one second energy storage unit (125, 235) when said electrical signal (210) from said at least one piezoelectric element falls below a piezo threshold of electrical energy. [Invention 12] 12. The system (100) according to any one of claims 1 to 11, further comprising at least one regulator unit (120), preferably a Junction Field Effect Transistor (JFET) regulator, adapted to switch between a regulated mode and a non-regulated mode of the at least one regulator unit (120) based at least in part on a regulation threshold of electrical energy. [Invention 13] The system (100) of invention 12, wherein the regulation mode causes the at least one second energy storage unit (125, 235) to remain in a regulated voltage range between 1.0V and 4.0V, preferably between 1.5V and 3.5V, more preferably between 2.0V and 3.0V, or between 2.0V and 5.5V, or between 3.0V and 4.2V, such that electrical energy accumulates in the at least one first energy storage unit (115, 215). [Invention 14] 14. The system (100) according to claim 12 or 13, further comprising at least one comparator unit (147) adapted to measure said regulation threshold value of electrical energy. [Invention 15] 15. The system (100) according to any one of the preceding claims, further comprising at least one rectification unit (112) adapted to transform said electrical signal (210). [Invention 16] The signal processing unit (107), the first comparator unit (130), the second comparator unit (147), the first switching unit (135), the second switching unit (160), the third switching unit (170), or the battery unit (165), and has the following configuration: - said at least one piezo element (105) is connected to said signal processing unit (107); - said at least one rectifying unit (112) is connected between said at least one piezoelectric element (105) and said at least one first energy store (115, 215); - said at least one first energy storage unit (115, 215) is connected to at least one of said at least one regulator unit (120), said at least one converter unit (150, 200) or said power management unit (110); - said at least one regulator unit (120) is connected between said at least one first energy storage unit (115, 215) and said at least one second energy storage unit (125, 235) and is connected to said second comparator unit (147); - said at least one converter unit (150, 200) is connected to at least one of said at least one first energy store (115, 215), said at least one second energy store (125, 235) or said power management unit (110); - the at least one second energy storage unit (125, 235) is connected to at least one of the at least one third energy storage unit (140), the first comparator unit (130) or the second comparator unit (147), and is preferably connected to the at least one third energy storage unit (140) by the first switching unit (135); - the first comparator unit (130) is connected to the first switching unit (135); - the at least one third energy storage (140) is connected to at least one of the battery unit (165), the control unit (155) and the power management unit (110), and is preferably connected to the battery unit (165) by the second switching unit (160) and is preferably connected to the control unit (155) by the third switching unit (170); - said control unit (155) is connected to said power management unit (110); and - the power management unit (110) is connected to at least one of the signal processing unit (107), the second switching unit (160), or the third switching unit (170); The system (100) according to claim 15, comprising at least one of the following: [Invention 17] 17. The system (100) according to any one of claims 1 to 16, integrated into a cavity in the insole, midsole or outsole of a shoe. [Invention 18] 18. The system (100) according to any one of claims 1 to 17, wherein at least two piezoelectric elements (105) are arranged in the heel area and / or the forefoot area of ​​the shoe sole. [Invention 19] A shoe sole comprising a system (100) according to any one of claims 1 to 18. [Invention 20] A shoe, in particular a sports shoe, comprising a shoe sole according to invention 19. [Invention 21] A method for operating a system (100) according to any one of claims 1 to 18, comprising: a. generating said electrical signal (210) when a mechanical deformation of said at least one piezoelectric element (105) occurs; b. selectively controlling the transfer of an amount of electrical energy between the at least one first energy storage unit (115, 215) and the at least one second energy storage unit (125, 235); A method comprising: [Invention 22] 22. The method of claim 21, wherein the selectively controlling step includes switching the at least one converter unit (150, 200) between the charging state (285) and the discharging state (290) by using the switching frequency (280), wherein the electrical energy is transferred from the at least one first energy storage unit (115, 215) to the at least one converter unit (150, 200) in the charging state (285) and the electrical energy is transferred from the at least one converter unit (150, 200) to the at least one second energy storage unit (125, 235) in the discharging state (290). [Invention 23] 23. The method of claim 22, further comprising the step of calculating the switching frequency (280). [Invention 24] 24. The method according to any one of claims 21 to 23, further comprising switching the system (100) between the active mode (255) and the inactive mode (265) and / or between the regulated mode and the non-regulated mode. [Explanation of symbols]

[0080] 100 Systems 105 Piezo element 107 Signal Processing Unit 110 Power Management Unit 112 Rectifier Unit 115 First Energy Storage Unit 120 Regulator Unit 125 Second Energy Storage Unit 130 First comparator unit 135 First Switching Unit 140 Third Energy Storage Unit 147 Second Comparator Unit 150 Converter Unit 155 Control Unit 160 Second Switching Unit 165 Supercapacitor storage. Battery unit 170 Third Switching Unit 200 Flyback Converter 205 Transformer 210 Input voltage 215 First Capacitor 230 Output voltage 235 Second Capacitor 240 Control (switching) signals 242 Primary transformer side 245 Secondary transformer side 247 MOSFET Switch 250 Rectifier Unit 255 active mode 265 Inactive Mode 270 Lower Converter Threshold 275 Upper Converter Threshold 280 Switching Frequency 285 Charge Status 290 Discharge state

Claims

1. A system for a shoe sole, comprising: a. at least one piezo element adapted to produce an electrical signal when a mechanical deformation of the at least one piezo element occurs; b. at least one first energy storage unit and at least one second energy storage unit adapted to store electrical energy obtained from the electrical signal; c. at least one converter unit adapted to selectively control a transfer of an amount of electrical energy between the at least one first energy storage unit and the at least one second energy storage unit; Including, the system.

2. 2. The system of claim 1, wherein the at least one converter unit is adapted to selectively control the transfer of an amount of electrical energy based at least in part on a switching frequency between a charging state and a discharging state of the at least one converter unit.

3. The system of claim 2 , wherein the switching frequency is based at least in part on the electrical signal of the at least one piezoelectric element and / or on total power used by the system.

4. The system of claim 2 , further comprising a control unit adapted to calculate the switching frequency.

5. The system of claim 2 , wherein the charging state has a duration in the range of 20 ns to 180 ns.

6. 2. The system of claim 1, wherein the at least one converter unit has an active mode and an inactive mode, transitions between the active mode and the inactive mode are based at least in part on a lower converter threshold and / or an upper converter threshold for the electrical energy measured in the at least one first energy storage unit, and the selective control of the at least one converter unit is provided only in the active mode.

7. 2. The system of claim 1, wherein the at least one converter unit is a flyback converter, the flyback converter having a primary transformer side connected to the at least one first energy storage unit and a secondary transformer side connected to the at least one second energy storage unit.

8. 3. The system of claim 2, wherein the electrical energy is transferred from the at least one first energy storage unit to the at least one converter unit in the charging state, and the electrical energy is transferred from the at least one converter unit to the at least one second energy storage unit in the discharging state.

9. 3. The system of claim 2, wherein the at least one converter unit includes a metal oxide semiconductor field effect transistor switch adapted to switch the at least one converter unit between the charging state and the discharging state.

10. The system of claim 2 , further comprising a power management unit adapted to generate a control signal for switching the at least one converter unit between the charging state and the discharging state.

11. 2. The system of claim 1, further comprising at least one third energy storage unit adapted to store electrical energy obtained from the electrical signal and to provide electrical energy to the at least one second energy storage unit when the electrical signal from the at least one piezoelectric element falls below a piezo threshold of electrical energy.

12. The system of claim 1, further comprising at least one regulator unit, the at least one regulator unit adapted to switch between an regulating mode and a non-regulating mode of the at least one regulator unit based at least in part on an adjustment threshold of electrical energy.

13. 13. The system of claim 12, wherein the regulation mode causes the at least one second energy storage unit to remain in a regulated voltage range between 1.0 V and 4.0 V, such that electrical energy accumulates in the at least one first energy storage unit.

14. The system of claim 12 , further comprising at least one comparator unit adapted to measure the regulation threshold of electrical energy.

15. The system of claim 1 , further comprising at least one rectification unit adapted to convert the electrical signal.

16. The power supply may further include at least one of a signal processing unit, a first comparator unit, a second comparator unit, a first switching unit, a second switching unit, a third switching unit, a battery unit, at least one regulator unit, a power management unit, at least one third energy storage, or a control unit, and may have the following arrangements: said at least one piezo element is connected to said signal processing unit; said at least one rectifying unit is connected between said at least one piezo element and said at least one first energy store; the at least one first energy store is connected to at least one of the at least one regulator unit, the at least one converter unit or the power management unit; said at least one regulator unit is connected between said at least one first energy store and said at least one second energy store and is connected to said second comparator unit; said at least one converter unit is connected to at least one of said at least one first energy store, said at least one second energy store or said power management unit; the at least one second energy store is connected to at least one of the at least one third energy store, the first comparator unit or the second comparator unit and is connected to the at least one third energy store by the first switching unit; the first comparator unit is connected to the first switching unit; the at least one third energy store is connected to at least one of the battery unit, the control unit and the power management unit, and is connected to the battery unit by the second switching unit and to the control unit by the third switching unit; - said control unit is connected to said power management unit; and the power management unit is connected to at least one of the signal processing unit, the second switching unit or the third switching unit; The system of claim 15, comprising at least one of:

17. The system of claim 1 , integrated into a cavity in an insole, midsole, or outsole of a shoe.

18. The system of claim 1 , wherein at least two piezoelectric elements are positioned in a heel area and / or a forefoot area of ​​the shoe sole.

19. A shoe sole comprising the system according to claim 1.

20. A shoe, in particular a sports shoe, comprising a shoe sole according to claim 19.

21. 2. A method for operating the system of claim 1, comprising the steps of: generating said electrical signal when a mechanical deformation of said at least one piezoelectric element occurs; b. selectively controlling the transfer of an amount of electrical energy between the at least one first energy storage unit and the at least one second energy storage unit; A method comprising:

22. 22. The method of claim 21, wherein selectively controlling comprises switching the at least one converter unit between a charging state and a discharging state by using a switching frequency, wherein the electrical energy is transferred from the at least one first energy storage unit to the at least one converter unit in the charging state and the electrical energy is transferred from the at least one converter unit to the at least one second energy storage unit in the discharging state.

23. 23. The method of claim 22, further comprising the step of calculating the switching frequency.

24. The method described in claim 21, further comprising a step of switching the system between an active mode and an inactive mode of at least one converter unit, and / or between a regulated mode and an unregulated mode of at least one regulator unit.

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