JP2006129658A - Thermoelectric generator, DC-DC converter manufacturing method, and boost conversion method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for step-up conversion of a voltage generated in a thermoelectric conversion device to a practical level.
A PWM control circuit 2 is driven by a voltage across a resistor R2 generated by an input voltage Vi from a thermo module that converts heat of a heating element into electric power, and switching between an inductor L and one input terminal. At a high frequency. Thereby, a high voltage is generated between the output terminals by the back electromotive force generated in the inductor L.
[Selection] Figure 1

Description

  The present invention relates to a technique for boost-converting a voltage obtained by a thermoelectric conversion device by thermoelectrically converting heat of a heating element using a DC-DC converter.

  In recent years, the effective use of energy has been strongly desired. For this reason, attention is currently focused on thermal energy that is discarded without being used. This is because it is very effective to recover and utilize the thermal energy. For this reason, thermoelectric power generation that directly converts thermal energy into electrical energy has attracted attention.

  Thermal-electrical energy conversion processes are collectively referred to as thermoelectric conversion. In the recovery of unused thermal energy, an element (thermoelectric element) having a Seebeck effect (thermoelectric power generation) is usually used for thermoelectric conversion (Patent Documents 1 to 5). The thermoelectric element is usually used as a connected device (thermoelectric conversion device) as described in Patent Document 1, for example.

  The Peltier effect (thermoelectric cooling), which is in one-sided relationship with the Seebeck effect, is already widely used in the field of temperature control. On the other hand, techniques for performing thermoelectric power generation have been proposed in various documents including Patent Documents 1 to 5, but since the conversion efficiency from heat to electricity is as low as several percent, it is put to practical use. The situation is not reached. However, in principle, in thermoelectric conversion, electric power can be obtained simply by giving a temperature difference to the thermoelectric conversion device, so that it can also be expected as an energy source for a distributed power source. Since it can be applied to such a wide range of uses, recently, research on improving the efficiency of thermoelectric elements on a material basis has been actively conducted.

  If a temperature difference applied to a thermoelectric element is increased and a number of thermoelectric elements are connected to produce a thermoelectric conversion device, a sufficient voltage can be theoretically obtained by thermoelectric conversion. However, it is normal that a large temperature difference cannot be given to the thermoelectric elements, and there are usually restrictions on the number of thermoelectric elements that can be employed. For this reason, it is considered very important to step up and convert the voltage obtained by the thermoelectric conversion device to a practical level using a small temperature difference of about 10 to 20 ° C.

Note that current electronic devices are usually equipped with an RTC (Real Time Clock) that measures time and an SRAM (Static Random Access Memory) that stores user-specific data, and a power source for operating the device. Even when is off, they need to be powered. Currently, lithium batteries are often used as a backup power source, but have problems such as environmental problems, severe use at high temperatures, and replacement. Recently, FeRAM (Ferroelectric Random Access Memory) and MRAM (Magnetic Random Access Memory) are promising as non-volatile memory devices that can hold data without a backup power supply. As a backup power supply, it is necessary. For this reason, thermoelectric power generation is also desired to be applied to backup power sources.
Japanese Unexamined Patent Publication No. 2000-14026 JP 2001-308395 A Japanese Patent Laid-Open No. 2001-15657 JP 2001-282396 A JP-T-2002-518989

  An object of the present invention is to provide a technique for boosting and converting a voltage generated in a thermoelectric conversion device to a practical level.

  The thermoelectric power generation device of the present invention is based on the premise that power generation is performed by converting the heat energy of the heating element into electric energy, thermoelectric conversion means for converting the heat energy of the heating element into electric energy by thermoelectric conversion, and thermoelectric conversion A switching circuit that is driven by electrical energy obtainable by the means and performs switching at a predetermined frequency, and a step-up conversion means having an inductor that generates back electromotive force by the switching performed by the switching circuit.

  The method for producing a DC-DC converter according to the present invention is a method for producing a DC-DC converter in which a thermoelectric conversion device boosts and converts a voltage obtained by thermoelectrically converting the heat of a heating element. A switching circuit that is driven by a voltage that can be obtained and that performs switching at a predetermined frequency is adopted, and an inductor that generates a counter electromotive force by the switching is adopted in consideration of the frequency at which the switching circuit performs switching, and a thermoelectric A circuit obtained by applying a voltage obtained by the conversion device to the switching circuit and arranging an inductor at a position where the back electromotive force is generated by the switching performed by the switching circuit.

  The step-up conversion method of the present invention is a method for step-up conversion of a voltage obtained by thermoelectric conversion device thermoelectrically converting heat of a heating element to a DC-DC converter, and performs switching for an inductor as the thermoelectric conversion device. A thermoelectric conversion device capable of generating a voltage necessary for driving the switching circuit is prepared, and the DC-DC converter is determined as a switching circuit and an inductor in consideration of the voltage that can be obtained by the prepared thermoelectric conversion device. A switching circuit that performs switching at a frequency and an inductor having an inductance determined in consideration of the voltage are employed, and the voltage obtained by the thermoelectric conversion device is boosted and converted using the fabricated DC-DC converter. .

  The present invention provides a thermoelectric conversion device capable of generating a voltage necessary for driving a switching circuit that performs switching with respect to an inductor, and the voltage generated by the device is switched at a frequency determined in consideration of the voltage. Step-up conversion is performed by a DC-DC converter manufactured by employing an inductor having an inductance determined in consideration of the circuit and its voltage.

  By enabling the switching circuit constituting the DC-DC converter to be driven by the thermoelectric conversion device, it is possible to cause the DC-DC converter to perform step-up conversion using the back electromotive force generated in the inductor by switching. For this reason, it is possible to generate a voltage necessary as a power source while no power supply from other is required. Since the generated voltage varies depending on the voltage to be generated in the thermoelectric conversion device, the frequency at which switching is performed, and the inductance of the inductor, they may be determined so as to obtain a necessary voltage.

  In step-up conversion using the back electromotive force generated in the inductor, a higher switching frequency (1 MHz or higher) can be employed as compared with the case of using a transformer. Therefore, a small DC-DC converter (thermoelectric generator) that can obtain a necessary voltage can be more easily realized by adopting a low-inductance inductor.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a circuit configuration of a DC-DC converter employed in the thermoelectric generator according to the present embodiment.

  As shown in FIG. 1, the DC-DC converter (hereinafter abbreviated as “converter”) 1 has a capacitor Ci connected between input terminals, a capacitor Co between output terminals, and resistors R1 and R2 connected in series. Are connected in parallel, the inductor L and the diode SBD are connected in series between the capacitor Ci and the resistor R1, and the switching PWM control circuit 2 is connected between the capacitor L and the diode SBD, between the resistors R1 and R2, and one of the input terminals. Each circuit configuration is connected.

  An input terminal connected to the PWM control circuit 2 is, for example, a ground level. The control circuit 2 is produced in the form of an IC, for example. Driven by the voltage across the resistor R2, switching between the inductor L and one of the input terminals is performed at a predetermined frequency. The converter 1 generates a high voltage between the output terminals by a counter electromotive force generated in the inductor L by the switching.

  FIG. 2 is a diagram for explaining a thermo module that supplies power to the converter 1 employed in the thermoelectric generator according to the present embodiment. 2A is a top perspective view, and FIG. 2B is a side view.

  As shown in FIG. 2A, the thermo module 10 includes, for example, ten Peltier elements (indicated as “P1” in the figure) 11 in cascade connection, and as shown in FIG. Sandwiched and integrated with flat plates 12 and 13 having a high rate. The Peltier element 11 is composed of a bismuth (Bi) -tellurium (Te) P-type / N-type semiconductor pair. In the present embodiment, copper plates are used as the flat plates 12 and 13. The flat plates 12 and 13 have a size of 60 mm × 285 mm, and the distance between them is 5.5 mm. The number of Peltier elements 11 to be cascade-connected may be determined as appropriate.

  FIG. 3 is a diagram illustrating the relationship of the thermoelectric conversion voltage with respect to the temperature difference of the thermo module 10. As shown in FIG. 3, the module 10 has a function of obtaining a thermoelectric conversion voltage of 1 V at a temperature difference of 15 to 20 ° C. due to the Seebeck effect. Note that the voltage across the module 10 at this time is measured as no load.

  The converter 1 shown in FIG. 1 is manufactured on the assumption that a voltage generated by a thermo module (hereinafter abbreviated as “module”) 10 having a thermoelectric conversion function shown in FIG. 3 is input as an input voltage. As a result, it is necessary to boost the low voltage of about 1V obtained by thermoelectric conversion to a voltage that can hold the data in the RTC and SRAM, so it can be started at a low voltage, and is equivalent to the lithium battery used as a backup power supply. High-frequency switching is adopted in consideration of the fact that high-speed board design that requires high-density mounting is possible with the following sizes. Due to the adoption of high frequency switching, a Schottky diode is employed as the diode SBD.

  In order to confirm the difference in converter characteristics depending on the switching frequency, in this embodiment, two types of converters 1 having different switching frequencies are manufactured. FIG. 4 is a diagram showing main circuit constants for each switching frequency. In the figure, “Switching Frequency” is the frequency at which the adopted PWM control circuit 2 performs switching, “Inductance” is the inductance of the adopted inductor L, “Input Capacitance” is the capacitance of the adopted capacitor Ci, and “Output Capacitance” is The capacitances of the adopted capacitors Co are respectively shown. In any of the two types (types 1 and 2) of converters 1, a PWM control circuit 2 having a performance capable of starting from an input voltage of Vi = 0.85 V and capable of operating even if Vi is less than 0.8V. Is adopted.

FIG. 5 is a diagram for explaining characteristics required for data retention of SRAM and RTC.
As shown in FIG. 5, general-purpose RTCs and SRAMs can be backed up if the data retention voltage is 1.6V, and diode loss (0.5 to 0.6V) when applied to a backup circuit system is taken into consideration. The output voltage Vo was set to Vo = 2.8V so as to ensure 2V or more. The main circuit constants (parameters of devices constituting the converter 1) shown in FIG. 4 are determined in consideration thereof.

  FIG. 6 and FIG. 7 are diagrams showing the load characteristics of the converter 1 with switching frequencies of 3 MHz and 1.4 MHz, respectively. The relationship of the output voltage (Output Voltage) with respect to the output current (OutputCurrent) is shown for each input voltage of Vi = 0.8, 1.0, and 1.2V. These are inputs when the input is a voltage generated by a DC stabilized power supply. This is a reference to be compared with load characteristics when the module 10 is used as an input source.

  As shown in FIG. 6 and FIG. 7, the constant voltage characteristic range of Vo = 2.8V becomes narrower as the input voltage is lower, but it operates normally even at a low voltage of less than 1V. From this, it can be seen that any type of converter 1 has a performance capable of boosting a thermoelectric conversion voltage of about 1V. Further, since the output power is 0.3 W at 1.4 MHz with Vi = 1.2V, if 1.2V is realized as the thermoelectric conversion voltage when the converter 1 is operated, it is relatively large. It turns out that electric power can be obtained. This means that heat energy that generates a temperature difference of about 10 to 20 ° C. in a general electronic device can be recovered with high efficiency and reused as electric energy.

  8 and 9 are diagrams illustrating the output voltage waveform and the frequency spectrum of the output noise in the converter 1 with the switching frequency (fs) of 3 MHz and 1.4 MHz. FIGS. 8A and 9A show the output voltage waveform, and FIGS. 8B and 9B show the frequency spectrum of the output noise. In either case, the input is a voltage generated by a DC stabilized power supply. Here, the input voltage is Vi = 0.8 V, and the load is RL = 130 kΩ.

  As shown in FIGS. 8 and 9, the converter 1 having a switching frequency fs of 3 MHz has a larger ripple voltage and higher harmonic noise than that of 1.4 MHz. However, it can be seen that any converter 1 operates normally at Vi = 0.8 V, and the output voltage is accurate enough to serve as a backup power source (see FIG. 5).

Next, the case where the module 10 is used as an input source will be specifically described with reference to FIGS.
An experiment was conducted to determine whether or not the converter 1 can be activated using the module 10 shown in FIG. 2 as an input source. The module 10 is arranged in a form to be attached to a heat generating component (heating element: for example, a heat sink or a CPU of a power source). As a result of the experiment, the converter 1 was started 15 to 20 minutes after the start of the experiment, and the output voltage reached the set voltage value Vo = 2.8V. After start-up, when the input voltage reaches Vi = 0.85V, the boost operation starts. When the output voltage reaches the set voltage of Vo = 2.8V, the input voltage drops to Vi = 0.75V, but the operation can be maintained. It was. Although it reached 1V at the time of no load, it is considered that the input voltage has decreased to 0.75V with the energy required to start the converter 1 (PWM control circuit 2).

  FIG. 10 and FIG. 11 are diagrams showing the load characteristics of the converter 1 with the switching frequency fs of 3 MHz and 1.4 MHz when the module 10 is used as an input source. FIGS. 10 and 11 show the characteristics immediately after the converter 1 is started (plotted by a circle), the characteristics after 30 minutes have elapsed since startup (plotted by a square), and the characteristics after 60 minutes have elapsed (plotted by a triangle), respectively. ing.

  10 and 11, it can be seen that the constant voltage characteristic range tends to narrow immediately after startup. This is because the thermal energy is not in a steady state between the high temperature side and the low temperature side of the module 10, so that it is difficult to obtain stable electric energy, that is, the thermoelectric conversion is not stably performed and the input voltage fluctuates. It is thought that it is large. However, the load of the backup power supply for SRAM and RTC is about 1.2 μA (FIG. 5), and even if a plurality of SRAMs are used, it can be backed up by looking at about 10 μA. There is practically no problem with an output current of 0.2 mA. Furthermore, when the heat reaches a steady state, constant voltage characteristics can be obtained up to a range where the output current exceeds 0.8 mA, so that it can be determined that the function as a backup power source is sufficient. Here, even when Vi is set to 0.75 V using a DC stabilized power source for the input source of the converter 1, the output current has constant voltage characteristics in the range up to 0.8 mA, and the input source is the module 10 (thermoelectric It was confirmed that the output characteristics were the same as when conversion energy was input. That is, if the thermoelectric conversion voltage can achieve Vi = 1.2V, it can be determined that 0.3 W can be obtained as the output power.

  FIGS. 12 and 13 are diagrams illustrating the output voltage waveform and the frequency spectrum of output noise in the converter 1 with the switching frequency fs of 3 MHz and 1.4 MHz when the module 10 is used as an input source. Similar to FIGS. 8 and 9, FIGS. 12 (a) and 13 (a) show output voltage waveforms, and FIGS. 12 (b) and 13 (b) show output noise frequency spectra. . Here, the input voltage is Vi = 0.75V, and the load is RL = 130 kΩ.

  From FIG. 12 and FIG. 13, it can be seen that in any converter 1, the accuracy of the output voltage is at a level that does not cause a problem in actual use. However, when a DC stabilized power source is used as an input source (FIGS. 8 and 9), noise components that do not exist (circled in the figure) are confirmed. That is, it is noise other than the fundamental wave and harmonic components of the switching frequency fs, which is present in the same frequency band in the 3 MHz and 1.4 MHz converters 1. In order to investigate this noise component, the converter 1 was not connected, but a resistance load of 1 MΩ was connected to both ends of the module 10, and the frequency spectrum of the voltage at both ends was examined. For comparison, the same 1 MΩ resistive load was also connected to the DC stabilized power supply. The voltage across the module 10 was 1.2V, and the voltage across the DC stabilized power supply was 1.0V. The frequency spectrum of the DC stabilized power supply is shown in FIG. 14, and that of the module 10 is shown in FIG.

  As shown in FIG. 14, only the dark noise is observed with the DC stabilized power supply. However, in the module 10, as shown in FIG. 15, noise components with substantially equal frequency are observed over the entire range of 1 MHz to 10 MHz. This frequency component matches that observed as a component other than the switching frequency fs in the output noise (FIG. 12B, FIG. 13B) of the converter 1 using the module 10 as an input source. From this, it can be seen that this is a thermal noise and a noise component generated by the thermoelectric conversion action. In addition, the thermal noise generated by thermoelectric conversion can be confirmed to pass through a passive filter including the inductor L and the capacitor Ci of the converter 1 to reduce the frequency component.

  In this way, by adopting an appropriate module 10 and starting up the converter 1 (PWM control circuit 2) by the module 10 and performing step-up conversion, the module 10 and the converter 1 are always supplied with power from other sources. It can be used as a completely unnecessary power source (backup power source). The power supply can be applied to electronic devices as follows, for example. This will be specifically described with reference to FIGS.

FIG. 16 is a diagram illustrating an application example as a backup power source.
In the application example, during normal operation, power (energy) is supplied from the power supply VCC of the device body to a load 1602 having SRAM and RTC. The voltage V1 of the power supply VCC drops by a voltage drop ΔVs due to a loss in the middle at point A in the figure (A; V1−ΔVs). At the same time, the electric double layer capacitor Ced is charged through the diode D1, and the capacitor Ced is provided so as to function as a sub-backup power supply. The voltage V3 obtained by charging the capacitor Ced drops by a voltage drop ΔVd due to the diode D2 at a point A in the figure (A; V3−ΔVd). The output voltage V2 of the converter 1 using the thermoelectric conversion energy generated by the module 10 drops by a voltage drop ΔVd due to the diode D2 at point A in the figure (A; V3−ΔVd). From these facts, the magnitude relationship of the voltage at the point A is, for example, V3-ΔVD <V2-ΔVd <V1-ΔVs.
May be applied as a backup power source for electronic devices.

  Reference numeral 1601 in the figure denotes a system IC having a switch S1 and a diode D2. The power supply VCC and the load 1602 are connected by the switch S1, and the switch S1 is opened and closed according to the actual magnitude relationship according to the magnitude relationship setting. As a result, when the output voltage V2 of the converter 1 is practically available, the switch S1 is opened and the output voltage V2 of the converter 1 is used for backup. A capacitor Cst connected to the module 10 in parallel with the converter 1 is used as a startup capacitor.

  The situation in which the switch S1 is opened is a situation in which the device main body is turned off. In order to function when the power is turned off, the module 10 needs to transmit thermal energy from another device that is always operating.

FIG. 17 is a diagram illustrating an application example as a fan driving power source.
Some heat generating components (for example, a heat sink or a CPU of a power source) require cooling by a fan. In this application example, the module 10 is disposed on the heat generating component 1701 that needs to be cooled, for example, by placing it, and the thermal energy transmitted to the module 10 is converted into electric energy by thermoelectric conversion and supplied to the converter 1. The fan (FAN) 1702 for cooling the heat generating component 1701 is driven by the output voltage of the converter 1. When the component 1701 is not at a high temperature, that is, when it is not necessary to perform cooling, the fan 1702 is stopped because the input voltage from the module 10 is low, so that the self-control by the temperature difference generated in the module 10 can be performed. it can. Since driving is performed as necessary when necessary, life extension (maintenance-free) of the FAN 1702 can be realized in an appropriate form.

FIG. 18 is a configuration diagram of an electronic device equipped with an LCD.
The electronic device supplies power from the main power supply 1810 to the high-speed board 1800 and the inverter 1820, thereby driving the LCD of the LCD unit 1830 to the high-speed board 1800 and causing the inverter 1820 to drive the backlight of the unit 1830. It is. The high-speed board 1800 is provided with three local power supplies 1801 to 1803 which are POL (Point of Load) power supplies. The local power supply 1801 can supply power to the CPU 1804, the local power supply 1802 can supply power to the graphic LSI 1805, and the local power supply 1803 can supply power to the CPU 1804, the graphic LSI 1805, and the memory logic IC 1806. Electric power from the main power supply 1810 is supplied to a load 1807 such as a logic IC or a communication IC.

FIG. 19 is a diagram illustrating an application example of the electronic device as a POL power source.
In application as a POL power source, the module 10 is caused to transmit heat energy from a heat generating component 1701 as shown in FIG. In general, the POL power supply has a configuration using a step-down converter on a high-speed board. In the application example shown in FIG. 19, a local power source 1801 that is a POL power source on the high-speed board 1800 and a power source having the module 10 and the converter 1 can be switched and used. The system IC 1601 is used for switching. The switch S1 is closed in a situation where the voltage magnitude relationship at point A satisfies V2-ΔVd <V1-ΔVs. Thereby, in a situation where the output voltage V2 of the converter 1 can be practically used, the output voltage V2 is used, which can contribute to a reduction in power consumption of the device. In the configuration shown in FIG. 18, the LSI 1901 in the figure corresponds to both or one of the CPU 1804 and the graphic LSI 1805.

  In the present embodiment, a step-up converter is employed as the converter 1, but another type of converter may be used as long as it performs boost conversion using the back electromotive force of the inductor. For example, an inverting converter may be used. This is because the type using a transformer has a very large loss when switching at a high frequency.

  The heating element that transfers heat to the thermo module 10 is not particularly limited. For electronic devices that are worn on the body, the body temperature may be used. Since the module 10 performs thermoelectric conversion according to the temperature difference, the heating element may have a temperature lower than that of the surroundings. From this, the following applications can also be performed. This will be specifically described with reference to FIG.

  Under the ground, when it reaches a certain depth from the surface of the earth, it becomes almost constant temperature (around 15 ° C) throughout the year. On the other hand, the temperature of the surface of the earth varies relatively throughout the year. In Japan, the surface of the earth is lower than the underground in winter, and conversely in summer, the surface is higher than the underground. In FIG. 20, “TL” is a symbol representing a relatively low temperature, and “TH” is a symbol representing a relatively high temperature. The temperature fluctuations from day to day are usually large.

  From this, as shown in FIG. 20, the module 10 performs thermoelectric conversion due to the temperature difference generated between the underground and the ground surface, thereby causing the converter 1 to step up the voltage generated in the module 10. Also good. In such an application, since the vertical relationship between the temperature of the underground and the ground surface is not constant, a rectifier circuit or a switching circuit for switching the connection between the module 10 and the converter 1 is prepared to change the vertical relationship. It is desirable to be able to handle this. It can also be expected as a measure to prevent global warming by converting thermal energy into electrical energy.

  The length from the surface of the earth to the depth of the underground where the temperature is substantially constant is very large compared to the size of the module 10 even when the configuration shown in FIG. 2 is not adopted. It is necessary to prepare a mechanism for transferring the heat of at least one of the underground and the module 10 to the module 10. Since it is necessary to prepare such a mechanism, the module 10 does not have to be arranged on the ground surface or underground in the vicinity thereof.

It is a figure which shows the circuit structure of the DC-DC converter employ | adopted as the thermoelectric power generation apparatus by this Embodiment. It is a figure explaining the thermo module employ | adopted as the thermoelectric power generation apparatus by this Embodiment. It is a figure explaining the relationship of the thermoelectric conversion voltage with respect to the temperature difference of the thermo module shown in FIG. It is a figure which shows the main circuit constant according to switching frequency of the DC-DC converter employ | adopted as the thermoelectric generator by this Embodiment. It is a figure explaining the characteristic requested | required by the data holding | maintenance of SRAM and RTC. It is a figure which shows the load characteristic of a DC-DC converter whose switching frequency is 3 MHz. It is a figure which shows the load characteristic of a DC-DC converter whose switching frequency is 1.4 MHz. It is a figure explaining the frequency spectrum of the output voltage waveform and output noise in the DC-DC converter whose switching frequency is 3 MHz. It is a figure explaining the frequency spectrum of the output voltage waveform and output noise in the DC-DC converter whose switching frequency is 1.4 MHz. It is a figure which shows the load characteristic of a DC-DC converter whose switching frequency is 3 MHz at the time of using a thermo module as an input source. It is a figure which shows the load characteristic of a DC-DC converter whose switching frequency is 1.4 MHz when using a thermo module as an input source. It is a figure explaining the frequency spectrum of the output voltage waveform and output noise in the DC-DC converter whose switching frequency is 3 MHz when using a thermo module as an input source. It is a figure explaining the frequency spectrum of the output voltage waveform and output noise in the DC-DC converter whose switching frequency is 1.4 MHz when using a thermo module as an input source. It is a figure explaining the frequency spectrum of both-ends voltage at the time of connecting resistance of 1Mohm to direct current stabilized power supply. It is a figure explaining the frequency spectrum of the voltage of both ends at the time of connecting a resistance of 1 MΩ to both ends of the thermo module. It is a figure explaining the application example at the time of applying the thermoelectric generator by this Embodiment as a backup power supply. It is a figure explaining the application example at the time of applying the thermoelectric generator by this Embodiment as a fan drive power supply. It is a block diagram of the electronic device mounted with LCD. It is a figure explaining the application example at the time of applying the thermoelectric power generator by this Embodiment as a POL power supply of the electronic device shown in FIG. It is a figure explaining the application example using the temperature difference of an underground and the ground surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC-DC converter 2 PWM control circuit 10 Thermo module 11 Peltier device 12, 13 Flat plate L Inductor Ci, Co Capacitor SBD Diode R1, R2 Resistance

Claims (3)

In a thermoelectric generator that generates electricity by converting the heat energy of a heating element into electrical energy,
Thermoelectric conversion means for converting thermal energy of the heating element into electric energy by thermoelectric conversion;
A switching circuit that is driven by electrical energy that can be obtained by the thermoelectric conversion means and performs switching at a predetermined frequency, and a step-up conversion means having an inductor that generates back electromotive force by switching performed by the switching circuit;
A thermoelectric generator characterized by comprising: A method for producing a DC-DC converter in which a thermoelectric conversion device boosts and converts a voltage obtained by thermoelectrically converting heat of a heating element,
Adopting a switching circuit that performs switching at a predetermined frequency, driven by a voltage that can be obtained by the thermoelectric conversion device,
In consideration of the frequency at which the switching circuit performs switching, an inductor that generates a back electromotive force by the switching is adopted,
A voltage obtained by the thermoelectric conversion device is applied to the switching circuit, and the inductor is arranged in a circuit configuration in which a counter electromotive force is generated by switching performed by the switching circuit.
A manufacturing method of a DC-DC converter characterized by the above. A method in which a thermoelectric conversion device boosts and converts a voltage obtained by thermoelectrically converting the heat of a heating element by a DC-DC converter,
As the thermoelectric conversion device, a thermoelectric conversion device capable of generating a voltage necessary for driving a switching circuit that performs switching with respect to the inductor is prepared,
The DC-DC converter as the switching circuit and the inductor, a switching circuit that performs switching at a frequency determined in consideration of a voltage that can be obtained by the thermoelectric conversion device to be prepared, and the voltage Adopting an inductor with a determined inductance,
Using the produced DC-DC converter, the voltage obtained by the thermoelectric conversion device is boosted and converted.
A boost conversion method characterized by the above.