A bridge T type photovoltaic array and visible light information and energy transmission system

Abstract

The application discloses a bridge T type photovoltaic array and a visible light information and energy transmission system, wherein the bridge T type photovoltaic array comprises n parallel array units, an input resistor and an output resistor, each array unit comprises m series photovoltaic cells, a first inductor, a second inductor and a capacitor, the negative poles of the m series photovoltaic cells are connected to the ground, the positive pole of the first array unit is connected to the negative pole of the first inductor and the negative pole of the second inductor, the positive pole of the first inductor is connected to the positive pole of the capacitor, the positive pole of the second inductor is connected to the negative pole of the capacitor, and the n array units are connected in parallel through output ends and input ends. The application can realize significant and robust improvement in energy collection and communication performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optoelectronic communication, in particular to a bridge T-type photovoltaic array and a visible light information and energy transmission system. BACKGROUND

[0002] Traditional battery-powered maintenance is costly and difficult to sustain, while radio frequency spectrum resources are increasingly crowded. In this context, the light information and energy transmission (SLIPT) technology shows great potential, and a wireless optical communication and wireless energy supply fusion system, one of the application systems of SLIPT, emerges as the times require. The system uses a light-emitting diode (LED) or a laser diode as a transmitting end, which can not only carry information by modulating light intensity, but also transmit energy. When a photovoltaic cell is used as a light-electricity conversion and signal demodulation unit at the receiving end, information and energy transmission or acquisition can be realized simultaneously. Compared with traditional radio frequency schemes, wireless optical communication has abundant spectrum resources, high energy transmission efficiency, is not subject to electromagnetic interference, and has the characteristics of lighting and display. However, the single photovoltaic cell commonly used at the receiving end of the fusion system has inherent limitations. In actual applications, the constrained light receiving area and narrow field of view (FOV) of the single photovoltaic cell severely limit the performance of the system. For example, the limited receiving area of the single photovoltaic cell leads to low energy harvesting efficiency, and the narrow FOV easily causes signal loss, affecting the communication reliability. Although the use of a photovoltaic array can effectively solve these problems by expanding the light collection area, widening the field of view, and enhancing the output capacity, existing research on photovoltaic arrays for fusion system applications still has significant shortcomings. At present, research on photovoltaic arrays for wireless optical communication systems focuses on energy distribution optimization, rather than the high-performance information and energy receiving requirements of fusion systems. A few attempts to apply photovoltaic arrays to fusion systems are limited to traditional series-parallel structures. For example, existing schemes combine the outputs of multiple photovoltaic units in space or circuit to improve the detection area and output voltage, but such pure series-parallel layouts fail to break through the inherent bandwidth bottleneck of single cells. Another research introduces complex peripheral circuits, such as multi-channel sampling and dynamic reconfiguration switch matrices, which improves the flexibility of the system but brings about a sharp increase in power consumption and complexity, and the array design does not improve the communication bandwidth of the system. In addition, some schemes rely on external high reverse bias to expand the bandwidth, but this contradicts the original intention of self-powered and low-power consumption, and there is a conflict between energy harvesting and communication mode at the circuit level. Research that uses array geometric characteristics to achieve self-powered positioning and other special functions is limited by device bandwidth and can only support very low communication rates (such as kbps level). These existing schemes show that traditional series-parallel arrays can improve energy output or achieve specific functions to some extent, but they have not fundamentally optimized and improved the high-frequency communication performance of the array, and even exacerbated signal attenuation and bandwidth constraints, seriously affecting the overall performance of optical detection and communication. SUMMARY

[0003] The purpose of the application is to provide a bridge T type photovoltaic array and a visible light information and energy transmission system, which improves the communication bandwidth and energy collection performance of the wireless optical communication system by designing a passive structured array of photovoltaic devices, and solves the problems of the current fusion system in the photoelectric conversion unit; and solves the problems of the existing technology that cannot realize the balance and regulation of energy collection and information transmission, efficient use of wireless collected energy and continuous and stable self-energy supply of the system receiving end load.

[0004] The technical scheme of the application is a bridge T type photovoltaic array for a wireless optical communication and wireless energy transmission system, comprising: n parallel array units, an input resistor and an output resistor; each array unit comprises m series photovoltaic cells, a first inductor, a second inductor and a capacitor; the negative electrode of the m series photovoltaic cells is connected to ground; the positive electrode of the first array unit is connected to the negative electrode of the first inductor and the negative electrode of the second inductor; the positive electrode of the first inductor is connected to the positive electrode of the capacitor, and the connection end is defined as the input end of the array unit; the positive electrode of the second inductor is connected to the negative electrode of the capacitor, and the connection end is defined as the output end of the array unit; the n array units are connected in parallel through their output ends and input ends; the positive electrode of the input resistor is connected to the positive electrode of the first inductor in the first array unit, and the negative electrode of the input resistor is connected to ground; the positive electrode of the output resistor is connected to the positive electrode of the 2n inductor in the nth array unit, and the negative electrode of the output resistor is connected to ground.

[0005] Further, the passive network composed of the first inductor, the second inductor and the capacitor is used to construct the frequency response characteristics of the array, while introducing zero points and new poles.

[0006] Further, the input resistor is used to connect a virtual excitation source in the wireless optical communication and wireless energy transmission system to analyze the communication performance of the array.

[0007] Further, the signal and energy are extracted from the two ends of the output resistor as the output end of the array.

[0008] Further, the zero points introduced by the passive network are used to improve the gain of the medium frequency band in the system, and the new poles are used to expand the cutoff frequency of the system.

[0009] The visible light information and energy transmission system comprises:

[0010] The transmitting end comprises a first FPGA, an LED driving circuit and an LED module, the output end of the first FPGA is connected to the input end of the LED driving circuit, and the output end of the LED driving circuit is connected to the input end of the LED module.

[0011] The receiving end comprises a bridge T type photovoltaic array, an information and energy decoupling circuit, an energy collection circuit, a signal processing circuit and a second FPGA; the input end of the bridge T type photovoltaic array receives visible light from the LED module; the output end of the bridge T type photovoltaic array is connected with the input end of the information and energy decoupling circuit; the output end of the information and energy decoupling circuit is connected with the energy collection circuit and the signal processing circuit; and the output end of the signal processing circuit is connected with the second FPGA.

[0012] Further, the information and energy decoupling circuit is equivalent to a load network connected at the position of the output resistor in the circuit of the bridge T type photovoltaic array.

[0013] Further, the energy collection circuit supplies energy for the signal processing circuit.

[0014] Further, the photoelectric conversion unit of the receiving end has a wide field of view characteristic, which ensures that the system can stably realize the synchronous transmission of information and energy when the receiving end deviates from the optical axis.

[0015] Beneficial effects: Compared with the prior art, the present application has the following remarkable advantages: the present application can effectively expand the light receiving area and the receiving field of view by adopting the photovoltaic array, and can reshape the frequency response of the photoelectric conversion unit through the bridge T type circuit structure, that is, the wireless communication and energy collection performance can be synergistically improved, and the efficient utilization of the collected energy can ensure the continuous and stable self-power supply of the receiving end of the fusion system. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a bridge T type photovoltaic array circuit design of the present application;

[0017] Figure 2 It is a schematic diagram of the bridge T type photovoltaic array of the present application under four sub-cells;

[0018] Figure 3 It is a schematic diagram of the conventional series-parallel photovoltaic array of the present application under four sub-cells;

[0019] Figure 4 It is an equivalent circuit diagram of the bridge T type photovoltaic array of the present application under four sub-cells;

[0020] Figure 5 It is an equivalent circuit diagram of a single photovoltaic cell of the present application;

[0021] Figure 6 It is an equivalent circuit diagram of the conventional series-parallel photovoltaic array of the present application under four sub-cells;

[0022] Figure 7 It is a bridge T type photovoltaic array, a conventional series-parallel photovoltaic array and a single photovoltaic cell transfer function curve comparison result diagram of the present application;

[0023] Figure 8 A comparison test result chart of output characteristics of the bridged T-type photovoltaic array and single photovoltaic cell of the present application;

[0024] Figure 9 A comparison test result chart of frequency response of the bridged T-type photovoltaic array and single photovoltaic cell of the present application;

[0025] Figure 10 A maximum output power test result chart of the bridged T-type photovoltaic array structure of the present application constructed by using different models of photovoltaic cells;

[0026] Figure 11 A bandwidth test result chart of the bridged T-type photovoltaic array structure of the present application constructed by using different models of photovoltaic cells;

[0027] Figure 12 A principle block diagram of a visible light information and energy transmission system of the present application;

[0028] Figure 13 A spatial relative position diagram of the emitting end light source and the receiving end photoelectric conversion unit of a visible light information and energy transmission system of the present application;

[0029] Figure 14 A test result chart of the output power of the single photovoltaic cell and the bridged T-type photovoltaic array of the present application varying with the communication distance;

[0030] Figure 15 A test result chart of the output power of the single photovoltaic cell and the bridged T-type photovoltaic array of the present application varying with the movable visual field;

[0031] Figure 16 A test result chart of the bit error rate of the single photovoltaic cell and the bridged T-type photovoltaic array of the present application varying with the communication distance;

[0032] Figure 17 A test result chart of the bit error rate of the single photovoltaic cell and the bridged T-type photovoltaic array of the present application varying with the movable visual field;

[0033] Figure 18 A real object diagram of the bridged T-type photovoltaic array circuit under four sub-cells of the present application;

[0034] Figure 19 A real object connection block diagram of a visible light information and energy transmission system of the present application. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be further described below in combination with the drawings.

[0036] As Figure 1As shown, the embodiment of the present application provides a bridge T type photovoltaic array for wireless optical communication and wireless energy transmission system, comprising n parallel array units, wherein n is an integer greater than or equal to 1 and less than or equal to 100; the array unit comprises m series photovoltaic cells, wherein m is an integer greater than or equal to 1 and less than or equal to 100; the negative electrode of the m series photovoltaic cells is connected to ground.

[0037] The i-th array unit further comprises a (2i-1)th inductor, a (2i)th inductor and an i-th capacitor; wherein i is an integer from 1 to n; the positive electrode of the array unit is connected to the negative electrode of the (2i-1)th inductor and the negative electrode of the (2i)th inductor; the positive electrode of the (2i-1)th inductor is connected to the positive electrode of the i-th capacitor, and the connection end is defined as the i-th array unit input end; the positive electrode of the (2i)th inductor is connected to the negative electrode of the i-th capacitor, and the connection end is defined as the i-th array unit output end; the bridge T type photovoltaic array further comprises an input resistor and an output resistor; the positive electrode of the input resistor is connected to the positive electrode of the first inductor in the first array unit, and the negative electrode of the input resistor is grounded; the positive electrode of the output resistor is connected to the positive electrode of the 2n inductor in the n-th array unit, and the negative electrode of the output resistor is grounded.

[0038] Wherein, the n array units are connected in parallel through the i-th array unit output end and the (i+1)th array unit input end, and collectively receive optical signals and energy. The passive structure composed of the (2i-1)th inductor, the (2i)th inductor and the i-th capacitor is used to shape the frequency response characteristics of the array; the structure retains the first order original pole of the system, introduces a new pole at a higher frequency, and introduces a zero point at a lower frequency band; the zero point is used to effectively improve the gain of the system in the middle frequency band, and the new pole is used to significantly expand the cutoff frequency of the system.

[0039] The input resistor is used to connect a virtual excitation source in the system simulation model, so as to analyze and verify the communication performance of the array by measuring the frequency response characteristics between the two ends of the output resistor; in the entity circuit structure, the input resistor and the virtual excitation source are not necessary components. The signals and energy extracted between the two ends of the output resistor are used as the output end of the array.

[0040] The embodiment of the present application also provides a visible light information and energy transmission system, comprising a transmitting end, a receiving end, a bridge T type photovoltaic array, an information and energy decoupling circuit, an energy collection circuit, a signal processing circuit and a second FPGA, an input end of the bridge T type photovoltaic array receives visible light from an LED module, an output end of the bridge T type photovoltaic array is connected with an input end of the information and energy decoupling circuit, an output end of the information and energy decoupling circuit is connected with the energy collection circuit and the signal processing circuit, and an output end of the signal processing circuit is connected with the second FPGA. The energy collection circuit supplies energy for the signal processing circuit.

[0041] As shown in Figure 2 , taking an array composed of four photovoltaic cells as an example, the bridge T type photovoltaic array scheme of the present application realizes significant quantitative improvement in key performance indicators: numerical simulation and comparative experiments show that, compared with a single photovoltaic cell, the topology structure realizes 3.13 times bandwidth enhancement and obtains nearly four times output power improvement; at the same time, theoretical analysis shows that, compared with a four photovoltaic cell array adopting a traditional series-parallel scheme (as shown in Figure 3 ), the present application also realizes 2.87 times bandwidth enhancement. These results prove that, through the unique bridge T type passive network design, the present application not only inherits the inherent advantages of array structure in expanding the receiving area and broadening the field of view, but also fundamentally breaks through the bottleneck of the communication bandwidth of the traditional series-parallel array, so that the wireless energy collection and communication performance of the fusion system are significantly improved at the same time.

[0042] Embodiment 1: as shown in Figure 2 , the present application provides a bridge T type photovoltaic array comprising two array units (n n =2) and each unit being composed of two photovoltaic cells in series (m m =2), Figure 18 is a physical diagram of the bridge T type photovoltaic array, and this embodiment clearly shows the circuit design of the present application and its excellent performance in expanding the system bandwidth.

[0043] The specific composition of the bridge T type photovoltaic array is as follows: the first array unit comprises a first photovoltaic cell (PV 11 ) and a second photovoltaic cell (PV 21 ) in series, and the negative electrode is grounded. The unit also comprises a first inductor (L L a1 ), a second inductor (L L a2 ) and a first capacitor (C Ca1 The positive end of the array unit is connected. L a1 and L a2 The negative electrode; L a1 The positive terminal is connected to C a1 The positive electrode; L a2 The positive terminal is connected to C a1 The negative electrode is defined as the output terminal of the first array unit. The second array unit includes a third photovoltaic cell (PV). 12 ) and the fourth photovoltaic cell (PV) 22 The two inductors are connected in series, with their negative terminals grounded. The unit also includes a third inductor (…). L a3 ), fourth inductor ( L a4 ) and second capacitor ( C a2 The positive end of the array unit is connected. L a3 and L a4 The negative electrode; L a3 The positive terminal is connected to C a2 The positive electrode; L a4 The positive terminal is connected to C a2 The negative terminal is defined as the output terminal of the second array unit. The output terminal of the first array unit is connected in parallel with the input terminal of the second array unit, and the output terminal of the second array unit is used to output electrical signals and electrical energy. The array includes one input port and one output port. Input resistance ( Z 1) The positive terminal and the first inductor ( L a1 The positive terminal of the output resistor is connected to the ground, and its negative terminal is grounded; the output resistor ( Z The positive terminal of 0) and the fourth inductor ( L a4 The negative terminal of the circuit is connected to the ground. The input resistor is the internal resistance of the virtual excitation source used for simulation analysis; this resistor does not exist in the actual system. The output resistor, on the other hand, is the equivalent circuit of the subsequent circuit, serving as the output terminal for signals and energy.

[0044] To quantitatively analyze the communication performance of this embodiment, a small-signal equivalent circuit model of the first array unit is established (e.g., Figure 4 The transfer function is derived. In the equivalent circuit model, the two series-connected photovoltaic cell units are modeled as an ideal photocurrent source. i ph1 With a junction capacitanceC js Parallel, and with a parallel resistance r p1 The core structure is connected. In the actual analysis, due to the influence of the parallel large resistance (usually simplified as open circuit) on high-frequency AC small signal can be ignored, so the core passive element of the system frequency response is the junction capacitance C js . The passive network of the bridge T type structure, that is, the first inductance ( L a1 ), the second inductance ( L a2 ), the first capacitance ( C a1 ) and the output resistance ( Z 0), together with the equivalent junction capacitance of the photovoltaic cell C js Determine the decisive factor of the complete system transfer function. Through circuit analysis, the transfer function H array1 ( s ) has the following form:

[0045] ;

[0046] Among them, ; ; ;

[0047] The circuit structure realizes the frequency shaping function: a zero point is introduced in the relatively low frequency band, which effectively raises the gain of the system in the medium frequency band and enhances the signal-to-noise ratio of signal transmission; At the same time, a new pole is introduced in the frequency band higher than the original pole of the first-order system, which cooperates with the original dominant pole of the system to form a wider and smooth roll-off passband, thereby significantly extending the-3 dB cutoff frequency of the system.

[0048] Comparative Example 1: A single photovoltaic cell as the first comparative example of the present application, considering the traditional photovoltaic cell-based photovoltaic cell structure. The circuit design of this comparative example is simplified as: only one photovoltaic cell is included, the negative electrode is connected to the ground, and the positive electrode is used as the output terminal.

[0049] In order to quantitatively analyze the communication performance of this comparative example, the small signal equivalent circuit model of a single photovoltaic cell ( Figure 5 ) is established and its transfer function is derived. In the equivalent circuit model, the photovoltaic cell is modeled as an ideal photoelectric current source i ph2 , a depletion capacitance C dp , a diffusion capacitance C df, a small signal resistance r d with a parallel resistance R sh parallel, and with a series resistance R s The core structure in series. Through circuit analysis, the transfer function of a single photovoltaic cell is:

[0050] ;

[0051] wherein, ;

[0052] The transfer function exhibits a typical first-order low-pass characteristic, which only contains one dominant pole. The location of the pole is determined by the parasitic capacitance of the photovoltaic cell and the load resistance, resulting in a very limited system bandwidth, which severely restricts the communication rate. At the same time, its output power is limited by the physical area of a single cell, and the energy harvesting capacity is weak.

[0053] To intuitively compare the gap between the core advantages of the present application and the prior art, Figure 8 and Figure 9 The power output characteristic (P-V curve) and frequency response curve of the single photovoltaic cell and the bridge T-type photovoltaic array of Example 1 as a photoelectric conversion end are also given. P - V It should be noted that Figure 8 and Figure 9 The photovoltaic cell used in the test is BCSC452B3 of TDK Company. From the output characteristic curve, it can be seen that the single photovoltaic cell is limited by its effective light area, and the power value corresponding to the maximum output power point is significantly lower than that of the bridge T-type array composed of four identical cells. At the same time, from the frequency response curve comparison, it can be clearly observed that the -3 dB bandwidth of the single photovoltaic cell is very limited, and its transfer function curve starts to roll off at a lower frequency, while the curve of the bridge T-type array remains flat in the low frequency band, and the roll-off occurs at a higher frequency. This comparison result fully shows that the traditional single photovoltaic cell receiver is significantly worse in both output power and communication bandwidth, which constitutes a fundamental bottleneck for system performance.

[0054] To systematically verify the universality and reliability of the above conclusion, further select a variety of different models of photovoltaic cells (including different material systems, different light-sensitive areas, and different numbers of sub-cells to constitute a single cell module) to construct a traditional single cell receiving end and a bridge T-type array receiving end proposed by the present application, and compare the maximum output power and -3 dB bandwidth of the two. The test results are summarized in Figure 10 and Figure 11 It should be noted that Figure 10 andFigure 11 The battery models 1 to 7 are ANYSOLAR's KXOB25-14X1F-TB-ND, KXOB25-05X3FCT-ND, KXOB25-02X8FCT-ND, SM141K04LV-ND, and TDK's BCS1714B6, BCS2717B6, and BCSC452B3, respectively. Figure 10 It is clearly demonstrated that the bridged T-array structure delivers a significant increase in maximum output power for all tested models, thanks to its effective aggregation of photocurrents from multiple cells. More importantly, Figure 11 The bandwidth test results consistently show that the bridging T-array structure achieves a significant increase in bandwidth across different photovoltaic cells, overcoming the bandwidth bottleneck of a single cell. This series of cross-model comparative experiments strongly demonstrates that the bridging T-array structure proposed in this invention has broad applicability in improving system output power and communication bandwidth. Its performance advantage does not depend on a specific type of photovoltaic cell, but rather stems from the circuit topology used.

[0055] Comparative Example 2: A conventional series-parallel photovoltaic array serves as the second comparative example of this invention, considering the use of... Figure 3 The photovoltaic array shown is a traditional series-parallel structure, consisting of four photovoltaic sub-cells connected in a basic two-parallel, two-series configuration. The specific circuit design is as follows: the fifth photovoltaic cell (CE... 11 ) and the sixth photovoltaic cell (CE) 21 The first branch is formed by connecting the series of the first photovoltaic cells, and the negative terminal of the first branch is grounded; the seventh photovoltaic cell (CE) 12 ) and the eighth photovoltaic cell (CE) 22 The two branches are connected in series to form a second branch, with the negative terminal of the second branch grounded. The positive terminals of these two branches are then connected in parallel. The core difference between this structure and Embodiment 1 of the present invention is that it is entirely composed of photovoltaic cells connected in basic series and parallel, and does not contain any passive networks actively introduced by inductors and capacitors to shape the frequency response.

[0056] To quantitatively analyze the communication performance of this embodiment, a small-signal equivalent circuit model of a traditional series-parallel photovoltaic array is established. Figure 6 The transfer function is derived. In the equivalent circuit model, the photovoltaic cell units of the two branches are modeled as two ideal photocurrent sources. i ph3 and i ph4 With a junction capacitance C jsp Parallel connection, and then with a parallel resistor r p2 and r p3The core structure of the connection. In the actual analysis, since the influence of the parallel large resistance (usually simplified as open circuit) on high-frequency AC small signal can be ignored, the core passive element determining the system frequency response is the junction capacitance C jsp . The output resistance (R0) and the junction capacitance (Cj) together constitute the decisive factor of the complete system transfer function. Through circuit analysis, the transfer function of the traditional series-parallel photovoltaic array is: Z C jsp

[0057] ;

[0058] The above transfer function is similar to the transfer function of single cell in Comparative Example 1, and essentially still shows a first-order low-pass characteristic. Although the number of cells increases, it essentially only changes the output power size and does not introduce a new frequency shaping mechanism, so it does not fundamentally shift compared to the single cell system, which is beneficial to the expansion of bandwidth.

[0059] To verify the superiority of the present application, the frequency response curves of Example 1, Comparative Example 1 and Comparative Example 2 were simulated and analyzed. It should be noted that during simulation, for the transfer function of Example 1, C a1 The preferred capacitance value of Cj is 2 nF, L a1 The preferred inductance value of L is 50 μH, L a2 The preferred inductance value of L is 50 μH, Z The preferred resistance value of R0 is 50 Ω, C js The preferred capacitance value of Cj is 50 nF; for the transfer function of Comparative Example 1, R s The preferred resistance value of R0 is 0 Ω, r d || R sh The preferred resistance value of R0 is 10 kΩ, Z The preferred resistance value of R0 is 50 Ω, C j The preferred capacitance value of Cj is 100 nF; for the transfer function of Comparative Example 2, Z The preferred resistance value of R0 is 50 Ω, C jsp The preferred capacitance value of Cj is 100 nF. Figure 7 The comparative results of the amplitude-frequency response curves of the three structures are shown. From Figure 7 ​​It can be clearly seen that the transfer function curve of the traditional series-parallel photovoltaic array (comparative example 2) is almost completely coincident with that of the single cell (comparative example 1), indicating that the traditional array method has not brought any substantial improvement in the communication bandwidth, although it has improved the output current or voltage. In contrast, the transfer function curve of the bridged T-type photovoltaic array (example 1) proposed by the present application exhibits completely different characteristics: it is flatter in the low frequency band, and the amplitude roll-off occurs only at a higher frequency, so that its -3 dB bandwidth is significantly improved compared with the other two structures.

[0060] Example 2: Reference Figure 12 , and Figure 13 and Figure 19 , and

[0061] The transmitting end comprises a first FPGA, an LED driving circuit, and an LED module, the output end of the first FPGA is connected to the input end of the LED driving circuit, and the output end of the LED driving circuit is connected to the input end of the LED module. The first FPGA of the transmitting end is used for signal modulation and coding, and the LED driving circuit inputs a current with a proper size to the LED module, so that the light intensity of the LED module changes rapidly between light and dark to transmit information.

[0062] The receiving end comprises the bridged T-type photovoltaic array described in example 1, an information and energy decoupling circuit, an energy harvesting circuit, a signal processing circuit, and a second FPGA, the output end of the bridged T-type photovoltaic array described in example 1 is connected to the input end of the information and energy decoupling circuit. The function of the information and energy decoupling circuit of the receiving end is to separate the electrical energy and electrical signal converted by the bridged T-type photovoltaic array; the function of the energy harvesting circuit is to harvest and store electrical energy; the function of the signal processing circuit is to filter, amplify, and shape the electrical signal to improve the signal quality; and the second FPGA is used for signal demodulation and decoding to recover the original information sent by the transmitting end.

[0063] The energy harvesting circuit and the signal processing circuit are two parallel circuits, the output end of the information and energy decoupling circuit is connected to the input end of the energy harvesting circuit and the signal processing circuit, the output end of the energy harvesting circuit is connected to the input end of the signal processing circuit to supply power for the signal processing circuit, and the output end of the signal processing circuit is connected to the input end of the second FPGA.

[0064] In the physical verification test of the present application, the physical layer communication performance of the system is tested according to the connection relationship between the transmitting end and the receiving end shown in FIG. 19. Since the core purpose of this verification is to directly and clearly observe the communication waveform recovered by the photovoltaic array after the signal processing circuit, an oscilloscope is used as the signal observation terminal in the test configuration of the receiving end. The oscilloscope is only used as a temporary waveform capture and analysis device to replace the signal reading function that will be performed by the digital demodulation module in actual application, so as to facilitate the intuitive evaluation of the analog signal quality and transmission reliability. It is emphasized that, in addition to the temporary test link of introducing the oscilloscope for the purpose of observation, the core functional modules of the transmitting end and the receiving end in FIG. 19, including the energy harvesting circuit, the signal processing circuit, the decoupling circuit, the LED driving circuit, and the photovoltaic array, etc., have the same connection relationship and working principle as the system block diagram of the aforementioned embodiment. Therefore, the waveform and signal quality test results obtained in this physical verification can directly prove the effectiveness and reliability of the technical solution of the present application in actual physical layer transmission.

[0065] Figure 13 A schematic diagram of the spatial relative position of the light source of the transmitting end and the photoelectric conversion unit of the receiving end of the system described in this embodiment. The vertical distance between the transmitting end LED and the receiving end photovoltaic array is defined as D , and the offset distance between the projection point of the photovoltaic array center point and the LED optical axis on the receiving plane is defined as L . Based on this, the movable field of view angle α of the system satisfies the relationship tan α = L / D . This definition quantifies the effective movement range of the receiving end within the coverage range of the transmitting end, and in combination with the wide field of view (FOV) characteristic inherent in the bridging T-shaped photovoltaic array of the present application, it ensures that the system can still stably and reliably realize the synchronous transmission of information and energy in the application scenario with a certain offset.

[0066] Comparative Example 3: Visible Light Communication System Based on a Single Photovoltaic Cell: As the third comparative example of this invention, a conventional visible light information and energy transmission system based on a single photovoltaic cell is considered. The transmitter, information and energy decoupling circuit, energy harvesting circuit, signal processing circuit, and second FPGA modules of the system in this comparative example are identical in connection and function to the system described in Example 2, ensuring fairness in performance comparison. The only difference lies in the photoelectric conversion unit at the receiver: this comparative example uses a single photovoltaic cell, while Example 2 uses the bridged T-shaped photovoltaic array described in this invention. To ensure consistency in the comparison benchmark, both the single photovoltaic cell and the sub-cell modules constituting the bridged T-shaped array use BCSC452B3 photovoltaic cells from TDK.

[0067] The system in this comparative example was compared with the system in Example 2 to illustrate the comprehensive advantages of the system using the photovoltaic array of the present invention in terms of communication and energy harvesting performance. The tests were mainly conducted by monitoring two key indicators of the system under different conditions: output power and bit error rate (BER).

[0068] Figure 14 This demonstrates how the system output power varies with the vertical distance between the transmitter and receiver. D The curve represents the change in communication distance. It can be observed that, at any test distance, the system using a bridged T-array has significantly higher output power than the system using a single battery. This indicates that the present invention effectively improves the system's energy capture capability and communication distance by increasing the light-gathering area. Figure 15 This demonstrates how the system output power varies with the movable field of view (i.e. α , defined as tan α = L / D The curves show the changes in power. The results indicate that as the offset increases, the output power of both systems decreases, but the system using the bridged T-array maintains a higher output power throughout the entire offset range. This verifies that the array described in this invention, due to its inherent wide field of view, can maintain excellent energy harvesting performance even when the receiver is off-axis. Figure 16 and Figure 17 The data then presents the bit error rate (BER) curves as a function of communication distance and movable field of view, respectively, from the perspective of communication reliability. Both sets of data consistently demonstrate that, under the same conditions, the BER of the system using the bridging T-array of this invention is significantly lower than that of the system based on a single battery. This is because the array effectively improves signal quality by extending bandwidth and increasing intermediate frequency gain, thus achieving stable, low-BER data transmission even at greater distances and larger offset angles.

[0069] In summary, the present pair of examples is verified by the experimental data of the system that, compared with the traditional single cell receiving system, the bridging T-type photovoltaic array and the fusion system of visible light information and energy transmission proposed by the present application can realize significant and robust improvement in both energy collection and communication performance.

Claims

1. A bridging T-type photovoltaic array for use in wireless optical communication and wireless power transmission systems, characterized in that, include: The array consists of n parallel array units, an input resistor, and an output resistor. Each array unit includes m photovoltaic cells connected in series, a first inductor, a second inductor, and a capacitor. The negative terminal of the m photovoltaic cells connected in series is grounded. The positive terminal of the first array unit is connected to the negative terminals of both the first and second inductors. The positive terminal of the first inductor is connected to the positive terminal of the capacitor, and this connection is defined as the input terminal of the array unit. The positive terminal of the second inductor is connected to the negative terminal of the capacitor, and this connection is defined as the output terminal of the array unit. The n array units are connected in parallel through their output and input terminals. The positive terminal of the input resistor is connected to the positive terminal of the first inductor in the first array unit, and the negative terminal of the input resistor is grounded. The positive terminal of the output resistor is connected to the positive terminal of the 2nth inductor in the nth array unit, and the negative terminal of the output resistor is grounded.

2. The bridging T-type photovoltaic array according to claim 1, characterized in that, The passive network consisting of the first inductor, the second inductor, and the capacitor is used to construct the frequency response characteristics of the array, introducing zeros and new poles while retaining the original poles of the system.

3. A bridging T-type photovoltaic array according to claim 1, characterized in that, The input resistor is used to connect a virtual excitation source to analyze the array's communication performance.

4. A bridging T-type photovoltaic array according to claim 1, characterized in that, The signal and energy are extracted from both ends of the output resistor and used as the output of the array.

5. A bridging T-type photovoltaic array according to claim 1, characterized in that, The zeros introduced by the passive network are used to increase the gain of the system in the frequency band, and the new poles are used to extend the cutoff frequency of the system.

6. A visible light information and energy co-transmission system, implemented using a photovoltaic array as described in any one of claims 1-5, characterized in that, include: The transmitting end includes a first FPGA, an LED driver circuit, and an LED module. The output of the first FPGA is connected to the input of the LED driver circuit, and the output of the LED driver circuit is connected to the input of the LED module. The receiving end includes a bridging T-type photovoltaic array, an information and energy decoupling circuit, an energy harvesting circuit, a signal processing circuit, and a second FPGA; the input end of the bridging T-type photovoltaic array receives visible light from the LED module. The output of the bridged T-type photovoltaic array is connected to the input of the information and energy decoupling circuit; the output of the information and energy decoupling circuit is connected to the energy harvesting circuit and the signal processing circuit; the output of the signal processing circuit is connected to the second FPGA.

7. A visible light information and energy co-transmission system according to claim 6, characterized in that, The energy harvesting circuit powers the signal processing circuit.

8. A visible light information and energy co-transmission system according to claim 6, characterized in that, The photoelectric conversion unit at the receiving end has a wide field of view, ensuring that the system can stably achieve synchronous transmission of information and energy when the receiving end is off the optical axis.

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