Modular switching circuit for energy harvesting systems

Abstract

This invention discloses a modular switching circuit for an energy harvesting system, comprising a sampling circuit and a logic processing circuit. The sampling circuit and the logic processing circuit are connected in series. The logic processing circuit includes a differential section and a processing section, with the differential section and the processing section connected in series. The sampling circuit is used to receive the electric field induced signal of the output voltage of the energy harvesting device. This invention achieves rapid and accurate switching of the modular circuit of the energy harvesting system by utilizing a simple circuit structure, reducing the system size and losses during the switching process.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, specifically to a modular switching circuit for an energy harvesting system. Background Technology

[0002] Energy harvesting technology has emerged as an advanced solution in recent years to replace batteries for powering sensors, wearable devices, and mobile electronic devices. An energy harvesting system consists of two parts: an energy harvesting device and a power converter. The energy harvesting device acts as the interface between the weak energy from the external environment and electrical energy conversion, capturing energy from the environment and outputting it as AC power. The power converter rectifies and regulates the AC voltage output from the energy harvesting device to power electronic loads. However, due to the uncertainty of changes in the external environment, the AC voltage output by the energy harvesting device often varies widely, leading to large fluctuations in the input voltage of the power converter. These fluctuations often range from hundreds of millivolts to fifty volts. With such a wide input voltage range, the utilization rate of the circuit components and the efficiency of the converter both decrease.

[0003] Modular switchable circuits offer a solution to inefficiency across a wide input range. These circuits consist of low-voltage converters connected in series at the input and parallel at the output, allowing for dynamic adjustment of the number of modules operating within the power converter to accommodate different input voltage ranges. The number of modules increases when the input voltage is high, and decreases when the input voltage is low. This not only increases component utilization by using lower voltage-level devices but also improves circuit efficiency.

[0004] To facilitate module switching, the switching circuit can be divided into a sampling circuit that samples the input voltage, and a logic function processing circuit for logic control and module switching. Currently, there are two main methods for sampling the voltage of the energy harvesting device: the first is to directly sample using a differential amplifier connected in parallel across the output of the energy harvesting device, and the second is to use transformer coupling. However, both methods have certain drawbacks for energy harvesting systems. When using a direct parallel differential amplifier, the amplifier has high requirements due to the large variation in the input voltage range, resulting in poor economic efficiency. When using transformer coupling, the transformer occupies a large volume, which cannot meet the miniaturization requirements of energy harvesting systems. For the logic function processing circuit, in addition to ensuring the correctness of the control logic, it is also necessary to minimize the impact of the switching process on the power converter. Furthermore, the logic function processing circuit has high power consumption, making it unsuitable for energy harvesting circuits.

[0005] To address this issue, a modular switching circuit for energy harvesting systems is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a modular switching circuit for an energy harvesting system. By utilizing a simple circuit structure, it enables rapid and accurate switching of modular circuits in the energy harvesting system, reducing the system size and losses during the switching process, thus solving the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A modular switching circuit for an energy harvesting system includes a sampling circuit and a logic processing circuit, wherein the sampling circuit and the logic processing circuit are connected in series, the logic processing circuit includes a differential section and a processing section, the differential section and the processing section are connected in series, and the sampling circuit is used to receive an electric field induced signal of the output voltage of the energy harvesting device.

[0009] Preferably, the sampling circuit includes copper foil 1 and copper foil 2, wherein copper foil 1 is connected to the ground plane of the power converter, and copper foil 2 is suspended.

[0010] Preferably, the copper sheet 1 and copper sheet 2 are located in the same position but are different layers and have the same shape and size.

[0011] Preferably, the differential section includes a first differential circuit and a second differential circuit; the first differential circuit includes resistors R1, R2, R3, and R4, operational amplifier U1, and diode D1. Copper foil 1 is connected to one end of resistor R1, and the other end of resistor R1 is connected to the negative input terminal of operational amplifier U1. The output terminal of operational amplifier U1 is connected to the anode of diode D1. Copper foil 2 is connected to one end of resistor R2, and the other end of resistor R2 is connected to the positive input terminal of operational amplifier U1. One end of resistor R3 is connected to the negative input terminal of operational amplifier U1, and the other end of resistor R3 is connected to the cathode of diode D1. One end of resistor R4 is connected to the positive input terminal of operational amplifier U1, and the other end of resistor R4 is grounded.

[0012] The second differential circuit includes resistors R5, R6, R7, and R8, operational amplifier U2, and diode D2. One end of resistor R5 is connected to copper foil 1, and the other end of resistor R5 is connected to the positive input terminal of operational amplifier U2. One end of resistor R6 is connected to copper foil 2, and the other end of resistor R6 is connected to the negative input terminal of operational amplifier U2. The output terminal of operational amplifier U2 is connected to the anode of diode D2. One end of resistor R7 is connected to the positive input terminal of operational amplifier U2, and the other end of resistor R7 is connected to the cathode of diode D2. One end of resistor R8 is connected to the negative input terminal of operational amplifier U2, and the other end of resistor R8 is grounded.

[0013] The cathodes of diode D1 and diode D2 are connected to form a differential output voltage V. rec .

[0014] Preferably, the processing section includes capacitor C1, capacitor C2, resistor R9, diode D3, comparator U3, comparator U4, analog switch S, AND gate U5, and trigger U6; the differential section outputs voltage V. rec The negative input terminal of comparator U3 is connected to the positive input terminal of comparator U3, which is connected to the reference voltage V. ref The anode of diode D3 is connected to the negative input terminal of comparator U3, the output terminal of comparator U3 is connected to the CLK terminal of flip-flop U6, the cathode of diode D3 is connected to the positive input terminal of comparator U4, the analog switch S is connected in parallel with one end of capacitor C1 to ground, and the other end of analog switch S and the other end of capacitor C1 are respectively connected to the cathode of diode D3. The negative input terminal of comparator U4 is connected to the switching voltage V. switch The output of comparator U4 is connected to the D terminal of flip-flop U6. One end of capacitor C2 is grounded, and the other end of capacitor C2 is connected to one end of resistor R9 and the first input terminal of AND gate U5. The other end of resistor R9 is connected to the output of comparator U3. The second input terminal of AND gate U5 is connected to the power supply signal VCC. The output of AND gate U5 controls the opening or closing of analog switch S. The negative output terminal of flip-flop U6 is the switching signal.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] The modular switching circuit for an energy harvesting system described in this invention, compared with the prior art, achieves rapid and accurate switching of modular circuits in the energy harvesting system by utilizing a simple circuit structure, reducing the system size and the loss during the switching process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a modular switching circuit structure for an energy harvesting system according to the present invention;

[0018] Figure 2 This is a waveform diagram of a modular switching circuit for an energy harvesting system according to the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figures 1 to 2 This invention provides a modular switching circuit for an energy harvesting system, including a sampling circuit and a logic processing circuit. The sampling circuit and the logic processing circuit are connected in series. The logic processing circuit includes a differential section and a processing section, with the differential section and the processing section connected in series. The sampling circuit is used to receive the electric field induced signal of the output voltage of the energy harvesting device. The sampling circuit includes copper foil 1 and copper foil 2. Copper foil 1 is connected to the ground plane of the power converter, and copper foil 2 is suspended. Copper foil 1 and copper foil 2 are located in the same position but on different layers and have the same shape and size.

[0021] The differential section includes a first differential circuit and a second differential circuit; the first differential circuit includes resistors R1, R2, R3, and R4, operational amplifier U1, and diode D1. Copper foil 1 is connected to one end of resistor R1, and the other end of resistor R1 is connected to the negative input terminal of operational amplifier U1. The output terminal of operational amplifier U1 is connected to the anode of diode D1. Copper foil 2 is connected to one end of resistor R2, and the other end of resistor R2 is connected to the positive input terminal of operational amplifier U1. One end of resistor R3 is connected to the negative input terminal of operational amplifier U1, and the other end of resistor R3 is connected to the cathode of diode D1. One end of resistor R4 is connected to the positive input terminal of operational amplifier U1, and the other end of resistor R4 is grounded.

[0022] The second differential circuit includes resistors R5, R6, R7, and R8, operational amplifier U2, and diode D2. One end of resistor R5 is connected to copper foil 1, and the other end of resistor R5 is connected to the positive input terminal of operational amplifier U2. One end of resistor R6 is connected to copper foil 2, and the other end of resistor R6 is connected to the negative input terminal of operational amplifier U2. The output terminal of operational amplifier U2 is connected to the anode of diode D2. One end of resistor R7 is connected to the positive input terminal of operational amplifier U2, and the other end of resistor R7 is connected to the cathode of diode D2. One end of resistor R8 is connected to the negative input terminal of operational amplifier U2, and the other end of resistor R8 is grounded.

[0023] The cathodes of diode D1 and diode D2 are connected to form a differential output voltage V. rec The V rec The value is 0.1V, which is 1 / 10 of the output voltage of the sampling circuit.

[0024] The processing section includes capacitor C1, capacitor C2, resistor R9, diode D3, comparator U3, comparator U4, analog switch S, AND gate U5, and trigger U6; the differential section outputs voltage V. rec The negative input terminal of comparator U3 is connected to the positive input terminal of comparator U3, which is connected to the reference voltage V. ref The anode of diode D3 is connected to the negative input terminal of comparator U3, the output terminal of comparator U3 is connected to the CLK terminal of flip-flop U6, the cathode of diode D3 is connected to the positive input terminal of comparator U4, the analog switch S is connected in parallel with one end of capacitor C1 to ground, and the other end of analog switch S and the other end of capacitor C1 are respectively connected to the cathode of diode D3. The negative input terminal of comparator U4 is connected to the switching voltage V. switch The output of comparator U4 is connected to the D terminal of flip-flop U6. One end of capacitor C2 is grounded, and the other end of capacitor C2 is connected to one end of resistor R9 and the first input terminal of AND gate U5. The other end of resistor R9 is connected to the output of comparator U3. The second input terminal of AND gate U5 is connected to the power supply signal VCC. The output of AND gate U5 controls the opening or closing of analog switch S. The negative output terminal of flip-flop U6 is the switching signal.

[0025] like Figure 1 As shown, the sampling circuit is constructed using electric field coupling to capture the output voltage of the energy harvesting device; the logic processing circuit is used for logic control and module switching functions; the differential section is used to extract the sampled voltage signal, and the processing section is used to perform logic processing on the extracted voltage signal to generate the required drive signal.

[0026] like Figure 2 As shown, the sampling voltage V sample Waveform as Figure 2 As shown in (a), the waveform after the difference section is: Figure 2 V in (b) rec As shown, CLK is V rec and reference voltage V ref The result after comparator U3. Since the main function of comparator U3 is to obtain V... rec The zero-crossing signal, therefore V ref A smaller voltage value should be chosen. V per half-wave cycle rec Both voltages will charge capacitor C1 through diode D3, and capacitor C1 will then record V. sample Peak information V p V p and the set switching voltage V switchIn comparison, the D port signal of flip-flop U6 can be obtained. The D port signal of flip-flop U6, together with the CLK signal, controls the output of flip-flop U6. Combining the CLK and D port signals, the D port signal is sent to the output of flip-flop U6 on the rising edge of CLK. Resistor R1, capacitor C2, and AND gate U5 are used to prevent the D port signal from disappearing before it reaches flip-flop U6 when the rising edge of CLK arrives, which would cause a logic error in the output of flip-flop U6.

[0027] The inverting output terminal Q^ of flip-flop U6 is as follows Figure 2 As shown in (e), V can be effectively tracked. sample The waveform, in half a V sample V can be identified within the cycle p Size, and in V sample Switching module 2 in the power converter when it is close to zero can effectively reduce the losses generated during switching.

[0028] The sampling circuit continuously detects the peak value of the output voltage of the energy harvesting device. When the peak value of the output voltage of the energy harvesting device is lower than the switching voltage, the switching circuit controls the power conversion circuit to operate in single-module mode; when the output voltage of the energy harvesting device is higher than the switching voltage, the switching circuit controls the power conversion circuit to operate in a mode where both modules operate simultaneously.

[0029] The selection between single-module and dual-module operation is determined by the level of the switching signal. If the switching signal is high, the input side of one module is short-circuited, and that module is inactive. The switching time is determined by the moment when the output of the energy harvesting device first crosses zero after the switching signal changes. At this moment, the voltage across the input capacitor of the module is zero, reducing losses and achieving zero-point switching functionality.

[0030] In summary, the modular switching circuit for energy harvesting systems described in this invention, compared with the prior art, achieves rapid and accurate switching of modular circuits in energy harvesting systems by utilizing a simple circuit structure, reducing system size while also reducing losses during the switching process.

[0031] The above embodiments show and describe the basic working principle, main technical features and advantages of the present invention. However, the modular switching circuit for energy harvesting systems designed in this invention is not limited to the above embodiments, and there may be various variations and improvements of different embodiments. All such variations and improvements fall within the scope of the present invention as claimed, and the scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A modular switching circuit for an energy harvesting system, characterized in that, It includes a sampling circuit and a logic processing circuit, wherein the sampling circuit and the logic processing circuit are connected in series, and the logic processing circuit includes a differential part and a processing part, wherein the differential part and the processing part are connected in series, and the sampling circuit is used to receive the electric field induction signal of the output voltage of the energy harvesting device; The sampling circuit includes copper foil 1 and copper foil 2. Copper foil 1 is connected to the ground plane of the power converter, and copper foil 2 is suspended. The differential section includes a first differential circuit and a second differential circuit; the first differential circuit includes a resistor. ,resistance ,resistance ,resistance operational amplifier and diodes The copper foil 1 and the resistor One end is connected, the resistor The other end is connected to the operational amplifier The negative input terminal is connected to the operational amplifier. Output terminal and diode The anode connection of the copper foil 2 and the resistor One end is connected, the resistor The other end is connected to the operational amplifier The positive input terminal is connected, and the resistor One end is connected to the operational amplifier The negative input terminal is connected, and the resistor The other end is connected to the diode The cathode connection, the resistor One end is connected to the operational amplifier The positive input terminal is connected, and the resistor The other end is grounded; The second differential circuit includes resistors ,resistance ,resistance ,resistance operational amplifier and diodes The resistor One end of the resistor is connected to copper foil 1. The other end is connected to the operational amplifier The positive input terminal is connected, and the resistor One end of the resistor is connected to the copper foil 2. The other end is connected to the operational amplifier The negative input terminal is connected to the operational amplifier. The output terminal and diode The anode connection of the resistor One end is connected to the operational amplifier The positive input terminal is connected, and the resistor The other end is connected to the diode The cathode connection, the resistor One end is connected to the operational amplifier The negative input terminal is connected, and the resistor The other end is grounded; The diode Cathode and diode The cathodes are interconnected to form the differential output voltage. ; The processing section includes capacitors. ,capacitance ,resistance ,diode Comparator Comparator Analog switch and door and triggers The differential output voltage Comparator The negative input terminal is connected to the comparator. The positive input terminal is connected to the reference voltage. The diode anode and comparator The negative input terminal is connected to the comparator. The output terminal and the trigger of Terminal connection, the diode Cathode and comparator The positive input terminal is connected to the analog switch. With capacitor One end of the analog switch is connected in parallel to ground. The other end is connected to the capacitor The other end is connected to the diode. The cathode, the comparator The negative input terminal is connected to the switching voltage. The comparator The output terminal and the trigger of Terminal connection, the capacitor One end of the capacitor is grounded. The other end is connected to the resistor One end, and the door The first input terminals are connected together, and the resistor The other end is connected to the comparator The output terminal of the AND gate is connected. The second input terminal and the power supply signal Connection, the AND gate Output terminal controls analog switch The trigger is activated or deactivated. The negative output terminal is the switching signal.

2. A modular switching circuit for an energy harvesting system according to claim 1, wherein: The copper sheet 1 and copper sheet 2 are in the same position but are different layers and have the same shape and size.

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