TWI682616B - Multi-source energy harvester system and power conversion apparatus and method thereof - Google Patents

Abstract

A multi-source energy harvester system includes a power conversion apparatus. A first and a second energy harvester respectively harvests a first and a second energy and respectively provides a first and a second input power. The power conversion apparatus includes an adjustable impedance matching circuit and a power conversion circuit. The impedance matching circuit generates an adjusted power according to the first input power. The power conversion circuit converts a bus power to an output power. The energy harvester system controls a first and a second switch circuits according to the adjusted power and/or the second input to select and conduct one of the adjusted power or the second input power as the bus power, and adjusts an impedance of the adjustable impedance matching circuit to maximize a voltage of the adjusted power.

Description

Multi-input source energy extraction system and its power conversion device and method

The invention relates to a power conversion system, in particular to a power conversion system with multiple input sources. The invention also relates to a power conversion device and method used in a power conversion system.

The previous cases related to this case are: US patent application US 20180069405 A1 and "An Effective Multi-Source Energy Harvester for Low Power Applications, 2011, IEEE".

In FIG. 1, the US patent application US 20180069405 A1 discloses a prior art power conversion system with multiple input sources (power conversion system 1 with multiple input sources), the power conversion system 1 includes a complex DC-DC boost converter, It is used to correspondingly convert from different energy harvesters (such as solar panel energy harvesters, piezoelectric panel energy harvesters, wind energy harvesters, magnetic induction energy harvesters and wireless RF energy harvesters as shown in the figure) Multiple input power provided by the extractor, etc., and then select one of the power conversion paths through the input selection switch to provide output power to the subsequent load (such as the battery pack).

The disadvantage of the prior art shown in FIG. 1 is that it is provided with a complex DC-DC boost converter corresponding to a complex energy harvester, respectively, making the circuit size of the power conversion system 1 large And the cost is high. In addition, this prior art cannot track the maximum power point, so its power conversion efficiency is not good.

In Figure 2, the IEEE paper "An Effective Multi-Source Energy Harvester for Low Power Applications, 2011, IEEE" reveals a prior art power conversion system with multiple input sources (power conversion system 2 with multiple input sources), power supply The conversion system 2 is provided with a corresponding maximum power point tracking circuit corresponding to the complex input source, and a corresponding diode is provided to select the highest voltage among different input sources, and the selected input power supply VSC is passed through DC -The DC converter is converted to the output power VOUT.

The disadvantage of the prior art shown in FIG. 2 is that, because the corresponding maximum power point tracking circuits are provided, the circuit size of the power conversion system 2 is large and the cost is high. In addition, the selection of the input source with a diode can only select the highest voltage in the input power supply.

Compared with the prior art in FIGS. 1 and 2, the present invention should share a maximum power point tracking circuit and a DC-DC conversion circuit in a complex input source. Therefore, the circuit size can be reduced and the cost can be reduced. The impedance matching circuit with adjustable impedance increases the voltage of the input power supply.

In one aspect, the present invention provides a power conversion device in which a first energy harvester extracts a first energy to provide a first input power source, and a second energy harvester extracts a second energy A second input power supply is provided; the power conversion device includes: an adjustable impedance matching circuit that generates an adjusted power supply at the first node according to the first input power supply; and a first switching circuit coupled to the first Between a node and a bus node; a second switch circuit, coupled between the second input power supply and the bus node; a switching control circuit, used to adjust the voltage of the adjusted power supply and/or the second input The voltage of the power supply to control the first switch circuit and the The second switch circuit selects one of the adjusted power supply or the second input power supply to generate a bus power supply at the bus node, and the conversion control circuit generates an impedance control signal for adjusting the adjustable impedance matching An impedance value of the circuit to maximize the voltage of the adjusted power supply; and a power conversion circuit that converts the bus power to generate an output power.

In a preferred embodiment, the conversion control circuit generates the bus power according to one of the following methods: (1) Compare the voltage of the adjusted power supply with the voltage of the second input power supply to select the adjusted power supply and the Among the second input power, the highest voltage is used as the bus power; or (2) comparing the voltage of the second input power with the first preset voltage, when the voltage of the second input power is higher than the first preset When the voltage is high, the second input power is selected to be turned on as the bus power.

In a preferred embodiment, the conversion control circuit generates a conversion control signal according to a first sensing signal to control the power conversion circuit so that the first input power or the second input power is controlled substantially at the respective The corresponding maximum power point; wherein the first sensing signal is related to at least one of the following: (1) the voltage of the adjusted power supply; (2) the voltage of the second input power supply; or (3) the voltage of the bus power supply .

In a preferred embodiment, the conversion control signal controls the output power of the power conversion circuit so that the first sensing signal is not lower than a second preset voltage, wherein the second preset voltage is related to the corresponding The maximum power point of the first input power supply or the maximum power point of the second input power supply.

In a preferred embodiment, the conversion control circuit includes: a sample-and-hold circuit for sampling and maintaining the divided voltage of the open-circuit voltage of the adjusted power supply as the bus when the adjusted power supply is selected as the bus power supply A second preset voltage; or when selecting the second input power as the bus power, sampling and maintaining the divided voltage of the open circuit voltage of the second input power as the second preset voltage.

In a preferred embodiment, the first input power supply has an AC form; wherein the power conversion device further includes a rectifier circuit, wherein the rectifier circuit includes at least one rectifier element, and the rectifier circuit is configured as one of the following: (1 ) The rectifying element is coupled between an output end of the adjustable impedance matching circuit and the first node to rectify an output signal of the adjustable impedance matching circuit to generate the adjusted power at the first node Or (2) the rectifier element is coupled between the first node and the bus node to rectify the adjusted power supply and generate the bus power supply at the bus node; wherein the first switching circuit includes the rectifier Element, the rectifier element is further used to control whether the adjusted power supply is turned on as the bus power supply.

In a preferred embodiment, the rectifying element is a rectifying diode.

In a preferred embodiment, the adjustable impedance matching circuit includes a variable capacitor for analogically and continuously adjusting the capacitance value of the variable capacitor according to the impedance control signal, thereby analogically and continuously adjusting the variable capacitor Adjust the impedance value of the impedance matching circuit.

In a preferred embodiment, the second switch circuit includes a path switch for controlling the conduction path of the second input power and the bus power, and the conversion control circuit includes a first comparison circuit for comparing the second A first comparison result is generated by the voltage of the input power source and the first preset voltage, and the conversion control circuit controls whether the path switch turns on the second input power source as the bus power source according to the first comparison result.

In a preferred embodiment, the conversion control circuit further determines whether to enable the impedance control signal according to the first comparison result, wherein when the voltage of the second input power supply is lower than the first preset voltage, the conversion The control circuit enables the impedance control signal.

In a preferred embodiment, the conversion control circuit includes: a bias sensing circuit, coupled between the bus node and a sensing node, for generating at the sensing node according to the voltage of the bus power supply A second sensing signal; a clamping circuit, coupled to the sensing node, for clamping the second sensing signal so that the second sensing signal is not greater than a clamping voltage; and a second ratio The comparison circuit is used to generate the conversion control signal according to the difference between the second sensing signal and a third preset voltage.

In a preferred embodiment, the bias sensing circuit includes: a bias resistor for providing a bias current; and a sensing capacitor coupled in parallel with the bias resistor to the bus power supply and the sense Between test nodes.

In a preferred embodiment, the bias resistor is a parasitic resistance of the sense capacitor.

In a preferred embodiment, the clamping circuit includes a clamping diode, wherein the clamping voltage is related to a forward voltage of one of the clamping diodes.

In a preferred embodiment, the conversion control circuit further generates the impedance control signal according to the conversion control signal.

In a preferred embodiment, the conversion control circuit periodically according to the comparison result of the voltage of the adjusted power supply and the voltage of the second input power supply, or periodically according to the voltage of the second input power supply and the first A comparison result of a predetermined voltage selects to turn on the adjusted power supply or the second input power supply as the bus power supply.

In a preferred embodiment, the power conversion circuit is configured as one of the following: (1) a boost switching power conversion circuit; (2) a buck switching power conversion circuit; (3) a buck-boost Type switching power conversion circuit; (4) a linear power conversion circuit; or (5) a charging circuit.

In a preferred embodiment, the second input power supply is further coupled to the adjustable impedance matching circuit to control the impedance value of the adjustable impedance matching circuit to increase the voltage of the adjusted power supply.

From another point of view, the present invention also provides a multi-input source energy harvesting system, including: the power conversion device as described in any of the foregoing embodiments; the first energy harvester; and the second Energy harvester.

From another point of view, the present invention also provides a method for controlling a multi-input source energy harvesting system, wherein the multi-input source energy harvesting system includes a power conversion device, a first energy harvester, and a A second energy extractor, wherein the first energy extractor extracts a first energy to provide a first input power, and the second energy extractor extracts a second energy to provide a second input power; The power conversion device includes: an adjustable impedance matching circuit that generates an adjusted power at the first node according to the first input power; a first switching circuit coupled between the first node and a bus node; A second switch circuit coupled between the second input power and the bus node; and a power conversion circuit that converts a bus power on the bus node to generate an output power; the method includes: according to the adjustment The voltage of the rear power supply and/or the voltage of the second input power supply control the first switching circuit and the second switching circuit to select one of the adjusted power supply or the second input power supply to be generated at the bus node The bus power supply; and adjusting an impedance value of the adjustable impedance matching circuit to maximize the voltage of the adjusted power supply.

In a preferred embodiment, the step of generating the bus power includes one of the following: (1) comparing the voltage of the adjusted power supply with the voltage of the second input power supply to select the adjusted power supply and the second input power supply Among them, the highest voltage is used as the bus power supply; or (2) comparing the voltage of the second input power supply with the first preset voltage, when the voltage of the second input power supply is higher than the first preset voltage, select Turn on the second input power as the bus power.

In a preferred embodiment, the method further includes: controlling the power conversion circuit according to a first sensing signal, so that the first input power or the second input power is substantially controlled at their respective maximum power points; Wherein the first sensing signal is related to at least one of the following: (1) The voltage of the adjusted power supply; (2) the voltage of the second input power supply; or (3) the voltage of the bus power supply.

In a preferred embodiment, the step of controlling the power conversion circuit includes: controlling the output power of the power conversion circuit so that the first sensing signal is not lower than a second preset voltage, wherein the second preset voltage It corresponds to the maximum power point of the first input power supply or the maximum power point of the second input power supply.

In a preferred embodiment, the second input power supply is further used to control the impedance value of the adjustable impedance matching circuit to increase the voltage of the adjusted power supply.

From another point of view, the present invention also provides a power conversion device, wherein a first energy harvester extracts a first energy to provide a first input power supply, and a second energy harvester extracts a second Energy to provide a second input power source; the power conversion device includes: an adjustable impedance matching circuit that generates an adjusted power source at the first node according to the first input power source, wherein the second input power source controls the adjustable impedance An impedance value of the matching circuit to maximize the voltage of the adjusted power supply; a power conversion circuit that generates an output power according to the adjusted power supply; and a conversion control circuit that generates a conversion control signal to control the The power conversion circuit enables the adjusted power to be controlled at the corresponding maximum power point.

In a preferred embodiment, the first energy harvester is a radio frequency antenna or an electromagnetic induction device, the first energy is wireless radio frequency energy, the first input power source is in the form of AC; and, the second energy harvester The extractor is a light energy battery, used to extract a light energy.

In a preferred embodiment, the power conversion device further includes: a first switch circuit coupled between the first node and a bus node; a second switch circuit coupled to the second input power and the Between bus nodes; wherein the conversion control circuit controls the first switching circuit and the second switching circuit according to the voltage of the adjusted power supply and/or the voltage of the second input power supply, to Selecting one of the adjusted power supply or the second input power supply to generate a bus power supply at the bus node; wherein the power conversion circuit converts the bus power supply to generate the output power supply.

In a preferred embodiment, the conversion control circuit further generates an impedance control signal for adjusting the impedance value of the adjustable impedance matching circuit to maximize the voltage of the adjusted power supply.

The detailed description will be given below through specific embodiments, so that it is easier to understand the purpose, technical content, characteristics and achieved effects of the present invention.

10,10’,10”‧‧‧adjustable impedance matching circuit

100,100’,100”‧‧‧Power conversion device

20‧‧‧ First switch circuit

200,300‧‧‧Energy Harvester

3A‧‧‧Multi-input energy harvesting system

30‧‧‧ Second switch circuit

40‧‧‧Power conversion circuit

50,50”‧‧‧switch control circuit

53,56‧‧‧Comparison circuit

54‧‧‧bias sensing circuit

55‧‧‧Clamp circuit

58‧‧‧impedance control circuit

60,60’‧‧‧rectifier circuit

80‧‧‧Switch circuit

Fr‧‧‧Resonant frequency

N1‧‧‧First node

NB‧‧‧bus node

PMAX‧‧‧Maximum power point

VA‧‧‧ Adjusted power supply

VB‧‧‧impedance control signal

VBUS‧‧‧Bus power supply

VCTL‧‧‧Conversion control signal

VI1‧‧‧First input power

VI2‧‧‧Second input power

VMP‧‧‧Max power voltage

VOC‧‧‧ open circuit voltage

VR1‧‧‧ preset voltage

VR1, VR2, VR3 ‧‧‧ second preset voltage

Figure 1 shows a block diagram of a prior art multi-input source energy harvesting system.

Figure 2 shows a block diagram of a prior art multi-input source energy harvesting system.

FIG. 3A shows a schematic diagram of an embodiment of a multi-input source energy harvesting system and a power conversion device of the present invention.

Figure 3B shows the characteristic curve corresponding to Figure 3A.

Figure 3C shows the characteristic curve of the energy harvester.

FIG. 3D shows a schematic diagram of an embodiment of the power conversion device of the present invention.

FIG. 4 shows a schematic diagram of an embodiment of an adjustable impedance matching circuit in the power conversion device of the present invention.

FIG. 5A shows a schematic diagram of an embodiment of the power conversion device of the present invention.

5B-5C are schematic diagrams of specific embodiments of the conversion control circuit in the power conversion device of the present invention.

FIG. 6A shows a schematic diagram of an embodiment of a rectifier circuit in the power conversion device of the present invention.

FIG. 6B shows a schematic diagram of an embodiment of a rectifier circuit and a switch circuit in the power conversion device of the present invention.

FIG. 7 shows a schematic diagram of a specific embodiment of a rectifier circuit and a switch circuit in the power conversion device of the present invention.

Figure 8 shows a schematic diagram of a specific embodiment of a rectifier circuit and a switch circuit in the power conversion device of the present invention.

FIG. 9 shows a schematic diagram of a specific embodiment of a conversion control circuit in the power conversion device of the present invention.

FIG. 10 shows a schematic diagram of a specific embodiment of a bias sensing circuit in the power conversion device of the present invention.

FIG. 11 shows a schematic diagram of a specific embodiment of a conversion control circuit in the power conversion device of the present invention.

FIG. 12 shows a schematic diagram of another embodiment of the multi-input source energy harvesting system and its power conversion device of the present invention.

Fig. 13 shows a schematic diagram of another embodiment of the multi-input source energy harvesting system and its power conversion device of the present invention.

FIG. 14 shows a schematic diagram of yet another embodiment of the multi-input source energy harvesting system and power conversion device of the present invention.

FIG. 15 shows a schematic diagram of another embodiment of the adjustable impedance matching circuit in the power conversion device of the present invention.

FIG. 16 shows a schematic diagram of another embodiment of the adjustable impedance matching circuit in the power conversion device of the present invention.

The drawings in the present invention are schematic, mainly intended to show the coupling relationship between the circuits and the relationship between the signal waveforms. The circuits, signal waveforms and frequencies are not drawn to scale.

Please refer to FIG. 3A. FIG. 3A shows a schematic diagram of an embodiment of the multi-input source energy harvesting system and its power conversion device of the present invention (multi-input source energy harvesting system 3A and power conversion device 100). The multi-input source energy harvesting system 3A includes complex energy harvesters 200 and 300 and a power conversion device 100.

The energy extractors 200 and 300 can be used to extract the first energy and the second energy in their corresponding forms and convert them into the first input power VI1 and the second input power VI2, respectively. In an embodiment, the energy harvester 200 can harvest energy in the form of AC and convert it into the first input power supply VI1 in the form of AC. For example, the energy harvester 200 can be a piezoelectric energy harvester. To capture and convert the vibration pressure energy and convert it into the first input power source VI1 in the form of AC. For another example, the energy extractor 200 may be a radio frequency antenna or an electromagnetic induction device to capture and convert wireless radio frequency energy or electromagnetic energy and convert It is the first input power supply VI1 in AC form. In an embodiment, the energy extractor 300 can extract energy in the form of DC and convert it into a second input power source VI2 in the form of DC. For example, the energy extractor 300 can be a photovoltaic cell or a thermoelectric element. The second input power source VI2 that captures light energy or heat energy and converts it into a DC form. Of course, the complex energy harvester of the multi-input source energy harvesting system can also be any combination of the above-mentioned various forms of energy harvesters.

Please continue to refer to FIG. 3A. The power conversion device 100 includes an adjustable impedance matching circuit 10, a first switching circuit 20, a second switching circuit 30, a conversion control circuit 50, and a power conversion circuit 40.

The adjustable impedance matching circuit 10 is used to generate the adjusted power supply VA at the first node N1 according to the first input power supply VI1. The first switch circuit 20 is coupled between the first node N1 and the bus node NB to control the conduction path between the first node N1 and the bus node NB. The second switch circuit 30 is coupled between the second input power VI2 and the bus node NB, and is used to control the conduction path between the second input power VI2 and the bus node NB.

The conversion control circuit 50 is used to control the first switching circuit 20 and the second switching circuit 30 according to the voltage of the adjusted power supply VA and/or the voltage of the second input power supply VI2 to selectively turn on the adjusted power supply VA or the second input power supply VI2 In one of them, the bus power VBUS is generated at the bus node NB. According to the present invention, the conversion control circuit 50 can select the adjusted power supply VA or the second input power supply VI2 as the bus power supply VBUS in many different ways. In one embodiment, the conversion control circuit 50 compares the voltage of the adjusted power supply VA with the voltage of the second input power supply VI2 to select the highest power supply voltage of the adjusted power supply VA and the second input power supply VI2 as the bus power supply VBUS. In another embodiment, the conversion control circuit 50 compares the voltage of the second input power supply VI2 with the first preset voltage, and selects to turn on the second input power supply VI2 when the voltage of the second input power supply VI2 is higher than the first preset voltage As the bus power VBUS.

In addition, according to the present invention, optionally, the conversion control circuit 50 may periodically according to the comparison result of the voltage of the adjusted power supply VA and the voltage of the second input power supply VI2, or periodically according to the voltage of the second input power supply VI2 and Based on the comparison result of the first preset voltage VR1, the power supply VA after the turn-on adjustment or the second input power VI2 is selected as the bus power VBUS.

The power conversion circuit 40 is used to convert the bus power VBUS to generate the output power VO. The power conversion circuit 40 may be configured as, for example but not limited to, a step-up switching power conversion circuit, a buck switching power conversion circuit, a buck-boost switching power conversion circuit, a linear power conversion circuit, or a charging circuit. It should be noted that the charging circuit refers to a power conversion circuit capable of at least a constant current power supply conversion mode and a constant voltage power supply conversion mode. Corresponding power conversion modes are carried out at different charging stages. The implementation details of the power conversion circuit are inferred by those skilled in the art under the teaching of the present invention, and will not be repeated here.

In addition, according to the present invention, in one embodiment, the conversion control circuit 50 is also used to generate an impedance control signal VB, adjust the impedance value of the adjustable impedance matching circuit 10, and then control or adjust the characteristic parameters of the adjusted power supply VA. Please also refer to FIG. 3B. FIG. 3B shows a characteristic curve corresponding to FIG. 3A. As shown in the figure, in the embodiment where the first energy is radio frequency energy and the energy harvester 200 is a radio frequency antenna, the adjustment may be The impedance value of the impedance matching circuit 10 can change the resonance frequency of the energy harvester 200, for example, to correspond to the resonance frequency Fr in FIG. 3B, so that the energy harvester 200 can extract the maximum energy while In the embodiment, by adjusting the impedance value of the adjustable impedance matching circuit 10, the voltage of the adjusted power supply VA can be controlled. In an embodiment, the conversion control circuit 50 adjusts the adjustable impedance matching circuit by the impedance control signal VB The impedance value of 10 is to maximize the voltage of the adjusted power supply VA.

Please refer to FIGS. 3A, 3C and 3D at the same time. FIG. 3C shows the characteristic curve of a typical energy harvester (such as a light energy harvester). FIG. 3D shows the embodiment of the power conversion device of the present invention. Schematic. As shown in FIG. 3C, the maximum power point PMAX of a typical energy harvester corresponds to a voltage where its open circuit voltage VOC is slightly lower (maximum power voltage VMP). In one embodiment, as shown in FIG. 3D, the conversion control circuit 50 is further used to generate a conversion control signal VCTL according to the first sensing signal VSEN1 to control the power conversion circuit 40 so that the first input power VI1 or the second The input power supply VI2 is roughly controlled at the corresponding maximum power point. In one embodiment, the conversion control signal VCTL controls the output power of the power conversion circuit 40 so that the first input power VI1 or the second input power VI2 is controlled at their respective maximum power points. It should be noted that the input power VI in the 3D diagram corresponds to the adjusted power VA or the second input power VI2 in the foregoing embodiment, and the switch circuit 80 is the corresponding first switch circuit 20 or second switch circuit 30 , Same below.

The first sensing signal VSEN1 can be implemented in various embodiments. Specifically, according to the present invention, the first sensing signal VSEN1 is related to at least one of the following: (1) the voltage of the adjusted power supply VA; (2) the second input The voltage of the power supply VI2; or (3) the voltage of the bus power supply VBUS. More specifically, when the conversion control circuit 50 selects to turn on the adjusted power supply VA to generate the bus power VBUS at the bus node NB, the conversion control circuit 50 generates a conversion control signal according to the voltage of the adjusted power supply VA or the voltage of the bus power VBUS VCTL to control the power conversion circuit 40 so that the first input power VI1 is controlled substantially at its maximum power point. When the conversion control circuit 50 selectively turns on the second input power VI2 to generate the bus power VBUS at the bus node NB, the conversion control circuit 50 generates the conversion control signal VCTL according to the voltage VVI2 of the second input power VI2 or the voltage of the bus power VBUS, The power conversion circuit 40 is controlled so that the second input power VI2 is controlled at its maximum power point.

It should be noted that due to the parasitic effects of the circuit parts or the matching between the parts, they are not necessarily ideal. Therefore, although the first or second input power supply is intended to be controlled at their respective maximum power points, in practice , The first or second input power supply may not be accurately controlled at their respective maximum power points, but only close to the maximum power point, that is, according to the present invention, it is acceptable to connect with the maximum power point due to the undesirable circuit There is a certain degree of error, which means that the aforementioned "substantially" is controlled at its maximum power point, and other references to "substantially" in this article are also the same.

The adjustable impedance matching circuit 10 may include basic impedance matching elements, such as inductors and capacitors, wherein the impedance matching element may be set to be adjustable, whereby the impedance value of the adjustable impedance matching circuit 10 may be adjusted, and then adjusted The impedance value (input or output impedance) of the multi-input source energy harvesting system and the power conversion device. Please refer to FIG. 4, which is a schematic diagram of an embodiment of an adjustable impedance matching circuit in the power conversion device of the present invention. As shown in the figure, in this embodiment, the adjustable impedance matching circuit 10 includes a variable capacitor 11 for analogically and continuously adjusting the capacitance value of the variable capacitor 11 according to the impedance control signal VB, thereby analogically and continuously Adjustable resistance The impedance value of the anti-matching circuit 10. In this specific embodiment, the adjustable impedance matching circuit 10 further includes an inductor L1 and a capacitor C12. In an embodiment, the variable capacitor 11 may be, for example, a voltage controlled variable capacitor or a voltage controlled variable capacitor diode D11. In an embodiment, the conversion control circuit 50 may correspondingly include an impedance control circuit 58 for generating an impedance control signal VB.

It should be noted that, in other embodiments, the variable capacitor 11 may also be a combination of a capacitor and a switch. In this case, the impedance control signal VB controls the switch to adjust the capacitance value of the variable capacitor 11.

In one embodiment, the conversion control signal VCTL controls the output power of the power conversion circuit 40 so that the first sensing signal VSEN1 is not lower than the second preset voltage, wherein the second preset voltage is related to the corresponding first input power VI1 Maximum power point or the maximum power point of the second input power supply VI2. Please refer to FIG. 5A. FIG. 5A shows a schematic diagram of an embodiment of the power conversion device of the present invention. As shown in FIG. 5A, in a specific embodiment, the conversion control circuit 50 may include a comparison circuit 51 for comparing The first sensing signal VSEN1 and the second preset voltage VR2 generate a conversion control signal VCTL to control the output power of the power conversion circuit 40 so that the first sensing signal VSEN1 is not lower than the second preset voltage VR2.

Specifically, when the conversion control circuit 50 selects to turn on the adjusted power supply VA to generate the bus power VBUS at the bus node NB, the second preset voltage VR2 is related to the maximum value of the first input power supply VI1 (or corresponding to the adjusted power supply VA) Power point. On the other hand, when the switching control circuit 50 selects to turn on the second input power VI2 to generate the bus power VBUS at the bus node NB, the second preset voltage VR2 is related to the maximum power point of the second input power VI2. Please also refer back to FIG. 3C. The second preset voltage VR2 may be, for example, the maximum power voltage VMP or a voltage close to it. It should be noted that the positive and negative terminals in the comparison circuit are relative concepts, which are only examples and not limitations.

5B-5C are schematic diagrams of specific embodiments of the conversion control circuit in the power conversion device of the present invention. As shown in FIG. 5B, in one embodiment, the switching control circuit 50 includes Including a sample and hold circuit 52 for sampling and maintaining the divided voltage of the open circuit voltage of the adjusted power supply VA as the second preset voltage VR2 when the adjusted power supply VA is selected as the bus power supply VBUS; or to select the second input power supply When VI2 is the bus power supply VBUS, it samples and maintains the divided voltage of the open circuit voltage of the second input power supply VI2 as the second preset voltage VR2. The above open circuit voltage may correspond to, for example, VOC in FIG. 3C. The open circuit voltage refers to the respective voltage when the current of the adjusted power supply VA, the first input power supply VI1, or the second input power supply VI2 is zero. In one embodiment, the divided voltage of the open circuit voltage may be obtained by R51 and R52 shown in the figure, for example. In one embodiment, the sample-and-hold circuit 52 includes a switch S51 and a capacitor C51. Please also refer to FIG. 5C. In an embodiment, the second switch circuit 30 (or the first switch circuit 20) may include a path switch SP to control the aforementioned conduction path. In a preferred embodiment, the sampling and The time point of maintenance is when the corresponding first switch circuit or second switch circuit is controlled to be off, in the embodiment as shown in FIG. 5C, that is, when the path switch SP is off, at the same time, switching control The circuit 50 may sample the switch S51 and the capacitor C51 and maintain the aforementioned partial voltage of the open circuit voltage to generate the second preset voltage VR2.

FIG. 6A shows a schematic diagram of an embodiment of a rectifier circuit in the power conversion device of the present invention. As described above, in an embodiment, the first input power VI1 may be in the form of AC. In this case, the power conversion device 100 may further include a rectifier circuit 60, where the rectifier circuit 60 includes at least one rectifier element 61. As shown in FIG. 6A, in this embodiment, the rectifying element 61 is coupled between the output terminal of the adjustable impedance matching circuit 10 and the first node N1 to rectify the output signal PAC of the adjustable impedance matching circuit 10. The adjusted power supply VA is generated at the first node N1.

FIG. 6B shows a schematic diagram of an embodiment of a rectifier circuit and a switch circuit in the power conversion device of the present invention. In an embodiment, the rectifier circuit may share part or all of the components of the switching circuit. For example, as shown in FIG. 6B, the rectifier circuit 60' is coupled between the first node N1 and the bus node NB. More specifically, the rectifier element 61' is coupled between the first node N1 and the bus node NB To rectify the adjusted power supply VA and generate the bus power supply VBUS at the bus node NB; In the embodiment, the first switching circuit 20 also includes a rectifying element 61'. The rectifying element 61' is further used to control whether the adjusted power supply VA is turned on as the bus power supply VBUS. In other words, the rectifying element 61' may correspond to the aforementioned path switch. As shown in FIGS. 6A-6B, in one embodiment, the rectifying element 61 (or 61') is a rectifying diode D61. In other embodiments, the rectifying element may also be a rectifying switch, which performs rectification by synchronous rectification.

FIG. 7 shows a schematic diagram of a more specific embodiment of a rectifier circuit and a switch circuit in the power conversion device of the present invention. In this embodiment, the rectifier circuit 60' includes rectifier diodes D61 and D62 to rectify the adjusted power supply VA, and generates a bus power supply VBUS at the bus node NB. In addition, the first switching circuit 20 also includes a rectifier diode The body D61 (corresponding to the aforementioned rectifying element), in this embodiment, the rectifying diode D61 may correspond to the aforementioned path switch, specifically, when the voltage of the adjusted power supply VA is higher than the voltage of the bus power supply VBUS, the rectifier The diode D61 is turned on, that is, the first input power VI1 is turned on as the bus power VBUS. On the other hand, when the voltage of the adjusted power VA is lower than the voltage of the bus power VBUS, the rectified diode D61 is turned off. That is, the conduction path between the first input power VI1 and the bus power VBUS is turned off.

FIG. 8 shows a schematic diagram of a specific embodiment of a rectifier circuit and a switch circuit in the power conversion device of the present invention. As shown in the figure, in one embodiment, the second switch circuit 30 includes a path switch SP for controlling the conduction path of the second input power VI2 and the bus power VBUS. In this embodiment, the conversion control circuit 50 includes a comparison circuit 53 To compare the voltage of the second input power supply VI2 with a preset voltage VR1 (for example, corresponding to the aforementioned first preset voltage) to generate a comparison result CP1, and the conversion control circuit 50 controls whether the path switch SP is turned on according to the comparison result CP1 The second input power supply VI2 serves as the bus power supply VBUS. In an embodiment, when the voltage of the second input power supply VI2 is higher than the preset voltage VR1, the path switch SP is controlled to be turned on and the second input power supply VI2 is selected to be turned on as the bus power supply VBUS. In one embodiment, when the voltage of the second input power supply VI2 is lower than the preset voltage VR1, the path switch SP is controlled to be turned off, that is, the second input power supply VI2 is turned off. The conduction path of the line power supply VBUS. In this case, the rectifier diode D61 in this embodiment is turned on when the voltage of the bus power supply VBUS is lower than the voltage of the adjusted power supply VA, that is, the first input power supply VI1 is turned on Bus power VBUS.

Please continue to refer to FIG. 8. In one embodiment, the conversion control circuit 50 further determines whether to enable the impedance control signal VB according to the first comparison result CP1. Specifically, the first comparison result CP1 can control whether the impedance control circuit 58 The enable impedance control signal VB (for example, by the enable signal EN, which is related to the first comparison result CP1) to control the impedance value of the aforementioned adjustable impedance matching circuit 10. Furthermore, in one embodiment, when the voltage of the second input power supply VI2 is lower than the preset voltage VR1, the second switching circuit will be turned off. At this time, the conversion control circuit 50 may enable the impedance control signal VB to The impedance value of the aforementioned adjustable impedance matching circuit 10 is controlled to maximize the power or voltage of the first input power source. On the other hand, in an embodiment, when the voltage of the second input power supply VI2 is higher than the preset voltage VR1, at this time, the conversion control circuit 50 disables the impedance control signal VB.

FIG. 9 shows a schematic diagram of another specific embodiment of the conversion control circuit for tracking the maximum power point in the power conversion device of the present invention. In one embodiment, the conversion control circuit 50 includes a bias sensing circuit 54, a clamping circuit 55 and a second comparison circuit 56.

The bias sensing circuit 54 is coupled between the bus node NB and the sensing node NS, and is used to generate a second sensing signal VSEN2 at the sensing node NS according to the voltage of the bus power VBUS. The clamping circuit 55 is coupled to the sensing node NS to clamp the second sensing signal VSEN2 so that the second sensing signal VSEN2 is not greater than the clamping voltage. The second comparison circuit 56 is used to generate the conversion control signal VCTL according to the difference between the second sensing signal VSEN2 and the third preset voltage VR3, thereby allowing the first input power supply VI1 or the second input power supply VI2 to be controlled approximately The corresponding maximum power point.

FIG. 10 shows a schematic diagram of a specific embodiment of a bias sensing circuit in the power conversion device of the present invention. In one embodiment, the bias sensing circuit 54 includes a bias resistor R53 and a sensing capacitor C52. Bias resistor R53 is used to provide bias current; sensing capacitor C52 and bias voltage The resistor R53 is coupled in parallel between the bus power VBUS and the sensing node NS. In one embodiment, the bias resistor R53 is the parasitic resistance of the sensing capacitor C52, that is, as far as the actual circuit is concerned, it is only necessary to provide the sensing capacitor in the bias sensing circuit 54.

Please continue to refer to FIG. 10. In one embodiment, the clamping circuit 55 includes a clamping diode D51, wherein the clamping voltage is related to the forward voltage of the clamping diode D51.

FIG. 11 shows a schematic diagram of a specific embodiment of a conversion control circuit in the power conversion device of the present invention. In this embodiment, the circuit setting of the maximum power point tracking of the conversion control circuit 50 is the same as that in FIG. 9 or 10. As shown in FIG. 11, in one embodiment, the conversion control circuit 50 generates impedance control according to the conversion control signal VCTL For the signal VB, specifically, the impedance control circuit 58 can also generate the impedance control signal VB according to the conversion control signal VCTL.

FIG. 12 shows a schematic diagram of another embodiment of the multi-input source energy harvesting system and its power conversion device of the present invention. In this embodiment, the multi-input source energy harvesting system 12 and the power conversion device 100' are similar to the embodiment of FIG. 3A, the difference is that in the power conversion device 100', the second input power source VI2 is more coupled to the adjustable The impedance matching circuit 10' is used to control the impedance value of the adjustable impedance matching circuit 10' to maximize the voltage of the adjusted power supply VA. Specifically, in an embodiment, the adjustable impedance matching circuit 10' further adjusts the impedance value of the adjustable impedance matching circuit 10' according to the voltage of the second input power supply VI2.

Please continue to refer to FIG. 12, according to the present invention, the above-mentioned settings have a special effect, the multi-input source energy harvesting system 12 can still start up smoothly when both the first and second energy are in a relatively poor state Output power to a subsequent circuit (such as a battery, etc.). For example, in this embodiment, the first and second energies are respectively radio frequency energy and optical energy, and the first and second energies 200 and 300 are respectively Corresponding radio frequency antennas and photovoltaic batteries may not provide enough voltage to enable the conversion control circuit 50 to generate an appropriate level of impedance control signal VB to control the adjustable impedance matching circuit 10' when the radio frequency energy is relatively low Impedance value The voltage of the adjusted power supply VA is maximized. In this case, in this embodiment, the second input power supply VI2 can be used to provide an appropriate bias voltage (for example, by the voltage of the second input power supply VI2) to match the adjustable impedance The circuit 10' controls the impedance value of the adjustable impedance matching circuit 10' to increase the voltage of the adjusted power supply VA (preferably maximized). When the voltage of the adjusted power supply VA is properly increased, the conversion control circuit 50 can generate an impedance control signal VB of an appropriate level to control the impedance value of the adjustable impedance matching circuit 10' to maximize the adjusted power supply VA Voltage to achieve the aforementioned functions. In this embodiment, the voltage of the second input power supply VI2 may not be high, but it is sufficient to provide an appropriate bias voltage to the adjustable impedance matching circuit 10' to control the impedance value of the adjustable impedance matching circuit 10' to improve the adjustment The voltage of the rear power supply VA. In one embodiment, as the bias voltage provided to the adjustable impedance matching circuit 10', the voltage of the second input power supply VI2 may be less than 1V. In one embodiment, the voltage of the second input power supply VI2 may be less than 0.5V.

Fig. 13 shows a schematic diagram of another embodiment of the multi-input source energy harvesting system and its power conversion device of the present invention. The power conversion device 100 ′ of this embodiment is similar to the power conversion device 100 ″ in FIG. 12, the difference is that the adjustable impedance matching circuit 10 ″ can not be controlled by the impedance control signal VB, but can be controlled by the second input power source VI2 The impedance value of the impedance matching circuit 10" can be adjusted. In other words, the conversion control circuit 50" can omit the impedance control signal VB, and the other functions of the conversion control circuit 50" can correspond to the conversion control in the aforementioned other embodiments (eg, FIG. 3A) Circuit 50.

FIG. 14 shows a schematic diagram of yet another embodiment of the multi-input source energy harvesting system and power conversion device of the present invention. The power conversion device 100" in FIG. 14 is similar to the power conversion device 100" in FIG. 13 except that the first switching circuit and the second switching circuit can be further omitted in the power conversion device 100" in FIG. 14. In this embodiment, in the power conversion device 100", the first energy harvester extracts the first energy to provide the first input power VI1, and the second energy harvester extracts the second energy to provide the second input. The power supply, wherein the first and second energy harvesters and the corresponding first and second energy respectively can refer to the related description in FIG. 3A, which will not be repeated here. In this embodiment, the power conversion device 100" includes an adjustable impedance matching circuit 10", a conversion control circuit 50", and a power conversion circuit 40.

In the embodiments of FIGS. 13 and 14, similar to the embodiment of FIG. 12, the second input power supply VI2 can be used to provide an appropriate bias voltage (for example, by the voltage of the second input power supply VI2) to the adjustable impedance The matching circuit 10' controls the impedance value of the adjustable impedance matching circuit 10' to increase the voltage of the adjusted power supply VA (preferably maximized).

Please continue to refer to FIG. 14, the adjustable impedance matching circuit 10" generates the adjusted power VA at the first node N1 according to the first input power VI1, wherein the second input power VI2 controls the impedance value of the adjustable impedance matching circuit 10", In order to maximize the voltage of the adjusted power supply VA. The power conversion circuit 40 generates the output power VO according to the adjusted power VA. In a specific embodiment, the power conversion circuit 40 converts the adjusted power VA to generate an output power VO. The conversion control circuit 50" is used to generate a conversion control signal VCTL to control the power conversion circuit 40, so that the adjusted power supply VA is roughly controlled at the corresponding maximum power point. In fact, when the adjusted power supply VA is roughly controlled at the corresponding maximum power In general, it also means that the first input power supply VI1 is controlled at the corresponding maximum power point.

FIG. 15 shows a schematic diagram of another embodiment of the adjustable impedance matching circuit in the power conversion device of the present invention. The power conversion device 100" of FIG. 15 and the adjustable impedance matching circuit 10" may correspond to the embodiments of FIGS. 13 and 14. As shown in FIG. 15, in this embodiment, the variable capacitor 11 of the adjustable impedance matching circuit 10" adjusts the capacitance value of the variable capacitor 11 analogously and continuously according to the second input power supply VI2, thereby analogically and continuously Adjust the impedance value of the adjustable impedance matching circuit 10. In a specific embodiment, the variable capacitor 11 adjusts the capacitance value of the variable capacitor 11 analogously and continuously according to the voltage of the second input power supply VI2.

FIG. 16 shows a schematic diagram of another embodiment of the adjustable impedance matching circuit in the power conversion device of the present invention. The power conversion device 100' of FIG. 16 and the adjustable impedance matching circuit 10' may correspond to the embodiment of Fig. 12. As shown in FIG. 16, in this embodiment, the variable capacitor 11 of the adjustable impedance matching circuit 10' can simultaneously and analogously and continuously adjust the variable capacitor 11 according to the impedance control signal VB and/or the second input power supply VI2 The capacitance value is used to adjust the impedance value of the adjustable impedance matching circuit 10 analogously and continuously. In a specific embodiment, the variable capacitor 11 adjusts the capacitance of the variable capacitor 11 analogously and continuously according to the voltage of the second input power supply VI2.

The present invention has been described above with reference to preferred embodiments, but the above are only for the purpose of making the person skilled in the art easy to understand the content of the present invention, and are not intended to limit the scope of the present invention. The illustrated embodiments are not limited to individual applications, but can also be used in combination. For example, two or more embodiments can be used in combination, and some components in one embodiment can also be used to replace another embodiment. Corresponding components. In addition, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations. For example, what the present invention calls "processing or operation according to a signal or generating an output result" is not limited to According to the signal itself, if necessary, the signal is subjected to voltage-current conversion, current-voltage conversion, and/or proportional conversion, etc., and then processed or calculated according to the converted signal to produce an output result. It can be seen that, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations, and there are many combinations, which are not described here one by one. Therefore, the scope of the present invention should cover all the above and other equivalent changes.

10 100 tunable impedance matching circuit switching power converter circuit 200 of the first device 20, an energy capturing device 300 3A multi-input source energy capture system 30 of the second switching circuit power conversion circuit 40 converts the control circuit 50 of the first node N1 bus node NB impedance control signal VBUS power supply VB bus power control signal VCTL converter VI1 VI2 second input of the first input power after the power adjustment VA

Claims (28)

A power conversion device is coupled to a first energy extractor and a second energy extractor, wherein the first energy extractor extracts a first energy to provide a first input power source, and the second energy The extractor extracts a second energy to provide a second input power supply; the power conversion device includes: an adjustable impedance matching circuit that generates an adjusted power supply at the first node according to the first input power supply; a first A switch circuit is coupled between the first node and a bus node; a second switch circuit is coupled between the second input power and the bus node; and a conversion control circuit is used according to the adjusted power supply Voltage and/or the voltage of the second input power supply to control the first switch circuit and the second switch circuit to select one of the adjusted power supply or the second input power supply to generate a bus at the bus node Power supply, and the conversion control circuit generates an impedance control signal for adjusting an impedance value of the adjustable impedance matching circuit to maximize the voltage of the adjusted power supply; and a power conversion circuit that converts the bus power to generate a Output power. The power conversion device as described in item 1 of the patent application scope, wherein the conversion control circuit generates the bus power according to one of the following ways: (1) comparing the voltage of the adjusted power supply with the voltage of the second input power supply to Select the adjusted power supply and the second input power supply with the highest voltage as the bus power supply; or (2) Compare the voltage of the second input power supply with the first preset voltage, and when the voltage of the second input power supply is higher than the first preset voltage, select and turn on the second input power supply as the bus power supply. The power conversion device as described in item 1 of the patent application scope, wherein the conversion control circuit generates a conversion control signal according to a first sensing signal to control the power conversion circuit so that the first input power or the second The input power supply is controlled at each corresponding maximum power point; wherein the first sensing signal is related to at least one of the following: (1) the voltage of the adjusted power supply; (2) the voltage of the second input power supply; or ( 3) The voltage of the bus power supply. The power conversion device as described in item 3 of the patent application range, wherein the conversion control signal controls the output power of the power conversion circuit so that the first sensing signal is not lower than a second preset voltage, wherein the second Assume that the voltage is related to the maximum power point of the first input power supply or the maximum power point of the second input power supply. The power conversion device as described in item 4 of the patent application range, wherein the conversion control circuit includes: a sample and hold circuit for sampling and maintaining the open circuit voltage of the adjusted power supply when the adjusted power supply is selected as the bus power supply Is used as the second preset voltage; or when selecting the second input power source as the bus power source, sampling and maintaining the divided voltage of the open circuit voltage of the second input power source as the second preset voltage . The power conversion device as described in item 1 of the patent application scope, wherein the first input power supply has an AC form; wherein the power conversion device further includes a rectifier circuit, wherein the rectifier circuit includes at least one rectifier element, wherein the rectifier circuit is provided It is one of the following: (1) The rectifying element is coupled between an output end of the adjustable impedance matching circuit and the first node for rectifying an output signal of the adjustable impedance matching circuit. A node generates the adjusted power supply; or (2) the rectifying element is coupled between the first node and the bus node to rectify the adjusted power supply and generate the bus power supply at the bus node; wherein the The first switching circuit includes the rectifying element, and the rectifying element is further used to control whether the adjusted power supply is turned on as the bus power supply. The power conversion device as described in item 6 of the patent application scope, wherein the rectifying element is a rectifying diode. The power conversion device as described in item 1 of the patent application range, wherein the adjustable impedance matching circuit includes a variable capacitor for analogically and continuously adjusting the capacitance value of the variable capacitor according to the impedance control signal, thereby The impedance value of the adjustable impedance matching circuit is adjusted analogously and continuously. The power conversion device as described in item 2 of the patent application scope, wherein the second switch circuit includes a path switch for controlling the conduction path of the second input power and the bus power, and the conversion control circuit includes a first comparison circuit For comparing the voltage of the second input power source with the first preset voltage to generate a first comparison result, and the conversion control circuit controls whether the path switch turns on the second input power source as the bus according to the first comparison result power supply. The power conversion device as described in item 9 of the patent application scope, wherein the conversion control circuit further determines whether to enable the impedance control signal according to the first comparison result, wherein when the When the voltage of the second input power is lower than the first preset voltage, the conversion control circuit enables the impedance control signal. The power conversion device as described in item 3 of the patent application range, wherein the conversion control circuit includes: a bias sensing circuit, coupled between the bus node and a sensing node, for determining the voltage of the bus power supply A second sensing signal is generated at the sensing node; a clamping circuit, coupled to the sensing node, is used to clamp the second sensing signal so that the second sensing signal is not greater than a clamping Voltage; and a second comparison circuit for generating the conversion control signal according to the difference between the second sensing signal and a third preset voltage. The power conversion device as described in item 11 of the patent application range, wherein the bias sensing circuit includes: a bias resistor for providing a bias current; and a sensing capacitor coupled in parallel with the bias resistor Between the bus power supply and the sensing node. The power conversion device as described in item 12 of the patent application range, wherein the bias resistance is a parasitic resistance of the sense capacitor. The power conversion device as described in item 11 of the patent application range, wherein the clamping circuit includes a clamping diode, wherein the clamping voltage is related to a forward voltage of one of the clamping diodes. The power conversion device as described in item 11 of the patent application scope, wherein the conversion control circuit further generates the impedance control signal according to the conversion control signal. A power conversion device as described in item 2 of the patent application range, wherein the conversion control circuit periodically compares the voltage of the adjusted power supply with the voltage of the second input power supply As a result, or periodically according to the comparison result of the voltage of the second input power supply and the first preset voltage, the adjusted power supply or the second input power supply is selected to be the bus power supply. The power conversion device as described in item 11 of the patent application scope, wherein the power conversion circuit is set to one of the following: (1) a boost switching power conversion circuit; (2) a buck switching power conversion circuit ; (3) a buck-boost type switching power conversion circuit; (4) a linear power conversion circuit; or (5) a charging circuit. The power conversion device as described in item 1 of the patent application range, wherein the second input power source is further coupled to the adjustable impedance matching circuit to control the impedance value of the adjustable impedance matching circuit to increase the adjusted value The voltage of the power supply. A multi-input source energy harvesting system includes: the power conversion device as described in any one of claims 1 to 18; the first energy harvester; and the second energy harvester. A method for controlling a multi-input source energy harvesting system, wherein the multi-input source energy harvesting system includes a power conversion device, a first energy harvester and a second energy harvester, wherein the first The energy extractor extracts a first energy to provide a first input power, and the second energy extractor extracts a second energy to provide a second input power; the power conversion device includes: an adjustable impedance matching The circuit generates an adjusted power supply at the first node according to the first input power supply; a first switch circuit is coupled between the first node and a bus node; a second switch circuit is coupled to the first Between two input power sources and the bus node; and a power conversion circuit that converts a bus power source on the bus node to generate an output power source; the method includes: Controlling the first switching circuit and the second switching circuit according to the voltage of the adjusted power supply and/or the voltage of the second input power supply to select one of the adjusted power supply or the second input power supply to turn on The bus node generates the bus power supply; and adjusts an impedance value of the adjustable impedance matching circuit to maximize the voltage of the adjusted power supply. The method of claim 20, wherein the step of generating the bus power includes one of the following: (1) comparing the voltage of the adjusted power supply with the voltage of the second input power supply to select the adjusted power supply and Among the second input power, the highest voltage is used as the bus power; or (2) comparing the voltage of the second input power with the first preset voltage, when the voltage of the second input power is higher than the first When setting the voltage, the second input power is selected to be turned on as the bus power. The method as described in item 20 of the patent application scope further includes: controlling the power conversion circuit according to a first sensing signal so that the first input power or the second input power is substantially controlled at their respective maximum powers Point; wherein the first sensing signal is related to at least one of the following: (1) the voltage of the adjusted power supply; (2) the voltage of the second input power supply; or (3) the voltage of the bus power supply. The method of claim 22, wherein the step of controlling the power conversion circuit includes: Controlling the output power of the power conversion circuit so that the first sensing signal is not lower than a second preset voltage, wherein the second preset voltage is related to the corresponding maximum power point of the first input power source or the second Enter the maximum power point of the power supply. The method of claim 20, wherein the second input power supply is further used to control the impedance value of the adjustable impedance matching circuit to increase the voltage of the adjusted power supply. A power conversion device, wherein a first energy extractor extracts a first energy to provide a first input power supply, and a second energy extractor extracts a second energy to provide a second input power supply; the power supply The conversion device includes: an adjustable impedance matching circuit, generating an adjusted power supply at the first node according to the first input power supply, wherein the second input power supply is coupled to the adjustable impedance matching circuit, and the second input power supply is used To control an impedance value of the adjustable impedance matching circuit to maximize the voltage of the adjusted power supply; a power conversion circuit to generate an output power according to the adjusted power supply; and a conversion control circuit to generate a conversion A control signal to control the power conversion circuit so that the adjusted power supply is generally controlled at the corresponding maximum power point. According to the power conversion device described in item 25 of the patent application scope, the first energy harvester is a radio frequency antenna or an electromagnetic induction device, the first energy is wireless radio frequency energy, and the first input power supply is in the form of AC; Moreover, the second energy harvester is a light energy battery, which is used to extract a light energy. The power conversion device as described in item 25 of the patent application scope further includes: a first switch circuit coupled between the first node and a bus node; a second switch circuit coupled to the second input Between the power supply and the bus node; wherein the conversion control circuit controls the first switching circuit and the second switching circuit according to the voltage of the adjusted power supply and/or the voltage of the second input power supply to selectively turn on the One of the adjusted power source or the second input power source generates a bus power source at the bus node; wherein the power conversion circuit converts the bus power source to generate the output power source. The power conversion device of claim 27, wherein the conversion control circuit further generates an impedance control signal for adjusting the impedance value of the adjustable impedance matching circuit to maximize the voltage of the adjusted power supply.

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