A circuit and system for energy co-transmission based on laser photovoltaic cells

Abstract

The application provides an energy and signal transmission circuit and system based on a laser photovoltaic cell, relates to laser wireless energy transmission and optical communication technology, and comprises the laser photovoltaic cell for receiving externally incident pulse modulation laser to convert into pulse photocurrent; the first end of the current sensing resistor is connected with the positive output end of the laser photovoltaic cell, and the second end forms a common node; when the pulse photocurrent flows through the current sensing resistor, a corresponding pulse voltage signal is formed at the common node; the common node is connected with an energy branch and a signal branch respectively; the pulse photocurrent passes through the energy branch to form a stable direct current voltage; and the pulse voltage signal passes through the signal branch to form a digital demodulation signal. The beneficial effect of the application is that only a single laser photovoltaic cell is used as the only photoelectric input device, and energy conversion and OOK signal demodulation are completed synchronously; the working power supply of all devices in the signal branch is directly taken from the energy branch output, and the system can be completely operated only by relying on incident laser, without external power supply access.

Description

Technical Field

[0001] This invention belongs to the field of laser wireless power transmission and optical communication technology, and in particular relates to a power and communication transmission circuit and system based on laser photovoltaic cells. Background Technology

[0002] Laser wireless power transfer technology transmits energy via directional laser beams, enabling contactless wireless power supply. This technology has significant application value in areas such as drone endurance, space energy transmission, and power supply for equipment in special scenarios. Laser photovoltaic cells, as the core component of the receiver, convert laser energy into electrical energy; devices optimized for specific wavelengths can achieve high photoelectric conversion efficiency.

[0003] If the transmitter uses pulse modulation to output laser light, the output current of the photovoltaic cell will synchronously exhibit pulse characteristics, enabling a single laser beam to simultaneously transmit energy and carry information—that is, synchronous transmission of energy and information. However, current related technical solutions still have core limitations: Using a multi-laser beam combining architecture, the transmitter needs to be configured with multiple lasers and beam combining devices to handle energy and signal transmission respectively, resulting in high hardware complexity, large size, high cost, and significant engineering integration difficulties; the receiver generally lacks dedicated signal demodulation circuits, often using analog voltage direct reading, which cannot output standard digital level signals and is difficult to directly interface with subsequent digital circuits, limiting practical engineering applications; in pulsed laser incident scenarios, no effective energy storage and voltage regulation stage is set up, and the receiver's output energy pulsates synchronously with the laser's on / off state, failing to provide continuous and stable DC power to the load; the circuit design simplifies the laser photovoltaic cell as an ideal current source, neglecting its nonlinear IV characteristics, which easily leads to the operating point deviating from the constant current region in actual operation, resulting in decreased energy conversion efficiency and insufficient system stability.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a power and signal transmission circuit and system based on laser photovoltaic cells, which is particularly suitable for simultaneously realizing wireless power supply and digital signal reception in pulsed laser links.

[0006] The technical solution adopted in this invention is as follows: Firstly, a power transmission circuit based on a laser photovoltaic cell is provided, comprising a laser photovoltaic cell, a current sensing resistor, a rectifier diode, an energy storage capacitor bank, a first voltage divider resistor, a second voltage divider resistor, a pull-up resistor, a pull-down resistor, and a voltage comparator.

[0007] The laser photovoltaic cell is used to receive externally incident pulsed modulated laser light and convert optical energy into pulsed photocurrent.

[0008] The first end of the current sensing resistor is connected to the positive output terminal of the laser photovoltaic cell, and the second end forms a common node;

[0009] When the pulsed photocurrent flows through the current sensing resistor, a corresponding pulsed voltage signal is generated at the common node;

[0010] The common nodes are respectively connected to the energy branch and the signal branch;

[0011] In the energy branch, the pulsed photocurrent output by the common node flows through the rectifier diode and is then input to the energy storage capacitor bank; the connection node between the cathode of the rectifier diode and the energy storage capacitor bank is the energy output terminal; after being smoothed and filtered by the energy storage capacitor bank, the pulsed photocurrent forms a stable DC voltage at the energy output terminal, which is used to supply power to the external load.

[0012] In the signal branch, the pull-down resistor is connected between the common node and the reference ground; the pulse voltage signal is input to the non-inverting input of the voltage comparator through the common node; the stable DC voltage is divided by the first and second voltage divider resistors connected in series to generate a reference voltage, which is proportional to the stable DC voltage and is input to the inverting input of the voltage comparator; the stable DC voltage is connected to the power supply of the voltage comparator for power supply; the voltage comparator has an open-drain output structure, and the output of the voltage comparator is pulled up to the stable DC voltage through the pull-up resistor, outputting a digital demodulated signal corresponding to the pulse-modulated laser.

[0013] Furthermore, the peak operating voltage of the laser photovoltaic cell Less than its maximum power point voltage This ensures that the laser photovoltaic cell remains in a near constant current region throughout the entire operating cycle;

[0014] The peak operating voltage The following relationship must be satisfied:

[0015] ;

[0016] in, This is the highest charging voltage of the energy storage capacitor bank. The forward voltage drop of the rectifier diode is... The peak value of the pulsed photocurrent. The resistance value of the current sensing resistor.

[0017] Furthermore, the resistance value of the current sensing resistor is... .

[0018] Furthermore, the rectifier diode is a Schottky rectifier diode, and when the forward current is 0.3A, the forward voltage drop is no greater than 0.35V.

[0019] Furthermore, the energy storage capacitor bank includes a main energy storage capacitor, the capacity of which is configured to reduce the steady-state output ripple rate of the energy branch to less than 10%.

[0020] Furthermore, the energy storage capacitor bank also includes a high-frequency decoupling capacitor, and the main energy storage capacitor and the high-frequency decoupling capacitor are connected in parallel.

[0021] Furthermore, the propagation delay of the voltage comparator is no greater than [value missing]. The total propagation delay of the signal branch is less than It can fully track the digital demodulated signal at 1 kHz and below.

[0022] Secondly, a laser photovoltaic cell-based energy and information transmission system is provided, comprising a pulsed laser emitting module and an energy and information transmission circuit:

[0023] The pulsed laser emitting module is used to output the pulsed modulated laser;

[0024] The simultaneous transmission circuit serves as a receiver, used to receive the pulse-modulated laser and synchronously output the stable DC voltage and the digital demodulated signal.

[0025] The advantages and positive effects of this invention are as follows: Due to the adoption of the above technical solution, only a single laser photovoltaic cell is used as the sole photoelectric input device, simultaneously completing energy conversion and OOK signal demodulation; the operating power of all devices in the signal branch is directly taken from the output of the energy branch, and the system can operate completely relying solely on the incident laser without the need for an external power supply; it ensures that the laser photovoltaic cell is in a near-constant current region throughout the entire working cycle, resulting in stable energy conversion efficiency and avoiding output performance fluctuations caused by operating point exceeding limits; it maintains a high-efficiency operating state without the need for an additional maximum power point tracking circuit, further simplifying the circuit architecture, reducing the number of devices, and improving system reliability. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the signal transmission of a simultaneous signal transmission circuit according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of a simultaneous communication circuit according to an embodiment of the present invention. Detailed Implementation

[0028] The present disclosure will now be described more fully with reference to the accompanying drawings, which illustrate exemplary embodiments of the present disclosure. The technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without creative effort are within the scope of protection of the present disclosure.

[0029] This invention provides an energy transmission circuit based on a laser photovoltaic cell, comprising a laser photovoltaic cell, a current sensing resistor, a rectifier diode, an energy storage capacitor bank, a first voltage divider resistor, a second voltage divider resistor, a pull-up resistor, a pull-down resistor, and a voltage comparator.

[0030] Laser photovoltaic cells are at least photoelectric conversion devices that can convert pulsed laser light of a specific wavelength into photocurrent. Device types include, but are not limited to, single-junction compound semiconductor photovoltaic cells, multi-junction compound semiconductor photovoltaic cells, and silicon-based photovoltaic cells. The type can be selected according to the incident laser wavelength and power level.

[0031] The types of current sensing resistors include, but are not limited to, precision metal film resistors and alloy sampling resistors. The resistance value can be flexibly adjusted according to the incident light current level and the target sampling voltage amplitude.

[0032] The output structure of a voltage comparator includes, but is not limited to, open-drain output and push-pull output. The open-drain output structure requires the use of a pull-up resistor.

[0033] Laser photovoltaic cells are used to receive externally incident pulsed modulated laser light and convert optical energy into pulsed photocurrent.

[0034] The first end of the current sensing resistor is connected to the positive output terminal of the laser photovoltaic cell, and the second end forms a common node. The current sensing resistor is used to convert the pulsed photocurrent into a pulsed voltage signal with a corresponding amplitude.

[0035] When the pulsed photocurrent flows through the current sensing resistor, a corresponding pulsed voltage signal is generated at the common node;

[0036] The common nodes are connected to the energy branch and the signal branch respectively;

[0037] In the energy branch, the pulsed photocurrent output from the common node flows through the rectifier diode and is then input into the energy storage capacitor bank; the connection point between the cathode of the rectifier diode and the energy storage capacitor bank is the energy output terminal; after the pulsed photocurrent is smoothed and filtered by the energy storage capacitor bank, a stable DC voltage is formed at the energy output terminal, which is used to supply power to the external load.

[0038] In the signal branch, a pull-down resistor is connected between the common node and the reference ground; the pulse voltage signal is input to the non-inverting input of the voltage comparator through the common node; the stable DC voltage is divided by the first and second voltage divider resistors in series to generate the reference voltage, which is proportional to the stable DC voltage and is input to the inverting input of the voltage comparator; the stable DC voltage is connected to the power supply of the voltage comparator for power supply; the voltage comparator has an open-drain output structure, and the output of the voltage comparator is pulled up to the stable DC voltage through a pull-up resistor, outputting a digital demodulated signal corresponding to the pulse-modulated laser.

[0039] The simultaneous transmission circuit can be equipped with additional technical features according to actual application requirements, including but not limited to power supply bypass capacitors, back-end linear voltage regulator circuits, high-speed comparator replacement, pull-down resistor value adjustment, etc. The selected features do not affect the realization of the core simultaneous transmission function of the circuit.

[0040] With the above setup, using only a single laser photovoltaic cell as the sole photoelectric input device, energy conversion and OOK signal demodulation are completed simultaneously, effectively simplifying the receiver hardware structure and reducing system size and material costs. The operating power of all devices in the signal branch is directly taken from the output of the energy branch, and the system can operate completely relying solely on the incident laser without the need for an external power supply, making it suitable for more power-free scenarios. The reference voltage is generated by voltage division at the energy output terminal and is in a fixed ratio to the output voltage. It can automatically adjust the demodulation threshold according to changes in laser power without the need for manual calibration, thus enhancing adaptability.

[0041] To address the problem that the nonlinear IV characteristics of laser photovoltaic cells can easily lead to operating point shift and decreased energy conversion efficiency, this embodiment provides an implementation method.

[0042] In one embodiment, the peak operating voltage of the laser photovoltaic cell Less than its maximum power point voltage This ensures that the laser photovoltaic cell remains in a near constant current region throughout its entire operating cycle.

[0043] Peak operating voltage The following relationship must be satisfied:

[0044] ;

[0045] in, This is the highest charging voltage for the energy storage capacitor bank. The forward voltage drop of the rectifier diode. This represents the peak value of the pulsed photocurrent. This is the resistance value of the current sensing resistor.

[0046] By adopting the above settings, the laser photovoltaic cell is kept in a near constant current region throughout the entire working cycle, ensuring stable energy conversion efficiency and avoiding output performance fluctuations caused by operating point exceeding the limit. It can maintain a high-efficiency working state without the need for an additional maximum power point tracking circuit, further simplifying the circuit architecture, reducing the number of components, and improving system reliability. Sufficient voltage safety margin is reserved to adapt to laser power fluctuations within a certain range, improving the robustness of circuit operation.

[0047] In one embodiment, the resistance of the current sensing resistor is .

[0048] In one embodiment, the rectifier diode may be of the following types, including but not limited to Schottky diodes, fast recovery diodes, and silicon rectifier diodes. When the forward current of the rectifier diode is 0.3A, the forward voltage drop is not greater than 0.35V. Preferably, the rectifier diode is a Schottky diode.

[0049] In one embodiment, the energy storage capacitor bank includes a main energy storage capacitor whose capacity is configured to reduce the steady-state output ripple rate of the energy branch to less than 10%.

[0050] In one embodiment, the energy storage capacitor bank further includes a high-frequency decoupling capacitor, and the main energy storage capacitor and the high-frequency decoupling capacitor are connected in parallel.

[0051] In one embodiment, the propagation delay of the voltage comparator is no greater than [missing value]. The total propagation delay of the signal branch is less than It can fully track digital demodulated signals up to 1kHz.

[0052] In one embodiment, all electronic components meet derating design requirements: the ratio of peak current to rated current of the rectifier diode is no greater than 1 / 3; the ratio of operating voltage to rated voltage of the energy storage capacitor is no greater than 1 / 3.2; the ratio of actual power consumption to rated power of the load is no greater than 1 / 4; the ratio of actual power consumption to rated power of the current sensing resistor is no greater than 1 / 11; the ratio of high-level amplitude of digital output to 1V requirement is no less than 3; and the ratio of operating point voltage to maximum power point voltage of the laser photovoltaic cell is no greater than 75%, improving the long-term reliability of the circuit.

[0053] In one embodiment, circuit simulation software can be used to verify the scheme: an equivalent model of a laser photovoltaic cell is constructed by connecting a pulse current source in parallel with a diode, a parallel resistor, and a series resistor. The current source outputs a pulse current of the corresponding level, and the matching pulse period and duty cycle are set. A complete simulation circuit is built according to the circuit topology, and transient simulation is performed to verify the steady-state voltage, ripple characteristics, and digital output signal waveform at the energy output terminal.

[0054] To better utilize a laser photovoltaic cell-based energy and information transmission circuit, this application also provides a laser photovoltaic cell-based energy and information transmission system, including a pulsed laser emitting module and an energy and information transmission circuit:

[0055] The pulsed laser emitting module is used to output pulsed modulated laser;

[0056] The simultaneous transmission circuit serves as the receiving end, used to receive pulse-modulated laser light and synchronously output a stable DC voltage and a digital demodulated signal.

[0057] This embodiment provides a preferred implementation method and describes in detail the specific structure and working process of the core technical solution of this application.

[0058] like Figure 2 As shown, in the simultaneous transmission circuit, the laser photovoltaic cell uses a vertical six-junction GaAs laser photovoltaic cell. Under the condition that the incident laser power corresponds to a short-circuit current of 0.3A, the open-circuit voltage is approximately 6.0V, the maximum power point voltage is approximately 5.0V, and the maximum power is approximately 1.5W. Current sensing resistor... resistance value It uses a precision metal film resistor with an accuracy of 1%, a rated power of 1W, and a temperature coefficient of no more than [value missing]. Current sensing resistor The first terminal is connected to the positive output terminal of the laser photovoltaic cell, and the second terminal forms a common node. Rectifier diode D1 is a Schottky rectifier diode, model 1N5819G, with a reverse withstand voltage of 40V, a rated current of 1A, and a forward voltage drop of approximately 0.30V at a forward current of 0.3A. The anode of rectifier diode D1 is connected to the common node, and the cathode is connected to the energy output terminal.

[0059] The energy storage capacitor bank includes a main energy storage capacitor C1 and a high-frequency decoupling capacitor C2, which are connected in parallel. The main energy storage capacitor C1 uses... Aluminum electrolytic capacitor, rated voltage 10V, equivalent series resistance not greater than The high-frequency decoupling capacitor C2 adopts... Multilayer ceramic capacitor, rated voltage 10V, 0805 package, X5R material. The upper end of the energy storage capacitor bank is connected to the energy output terminal, and the lower end is connected to the reference ground.

[0060] The voltage divider resistor network consists of a first voltage divider resistor. With the second voltage divider resistor The first voltage divider resistor is connected in series. resistance Second voltage divider resistor resistance The upper end of the series branch is connected to the energy output terminal, the lower end is connected to the reference ground, and the middle voltage divider node outputs the reference voltage. The reference voltage and the stable DC voltage at the energy output terminal are then compared. A fixed ratio. Pull-down resistor. resistance It connects the public node and the reference point.

[0061] Voltage comparator U1 is an open-drain output voltage comparator, model LMV331, in an SOT-23 package, with an operating voltage range of 2.7V to 5.5V and a typical propagation delay. The voltage comparator U1's non-inverting input (port 1) is connected to the common node, its inverting input (port 3) is connected to the voltage divider node, its power supply terminal (port 5) is connected to the energy output terminal, and its output terminal (port 4) is connected via... Pull-up resistor Connect to the power output terminal, and ground the ground terminal (port 2). Connect a 100nF bypass decoupling capacitor C3 in parallel between the power supply terminal (port 5) and the reference ground.

[0062] The peak operating voltage of the laser photovoltaic cell is lower than the maximum power point voltage, providing ample safety margin, and it operates in a near-constant current region throughout its entire lifecycle. The steady-state output average voltage of the energy branch is approximately 3V, with an output ripple rate of less than 10%; the total propagation delay of the signal branch is less than [missing value]. It can fully track OOK modulated signals up to 1kHz, and the high level of the output digital signal is approximately equal to the energy output voltage, while the low level is approximately equal to 0V.

[0063] like Figure 1 As shown, the complete flow of the pulsed photocurrent and pulsed voltage signals is as follows: The pulsed modulated laser (modulation mode OOK) generated by the laser is incident on the light-receiving surface of the laser photovoltaic cell. The laser photovoltaic cell converts the light energy into a pulsed photocurrent with a peak value of approximately 0.3A. The pulsed photocurrent flows through the current sensing resistor via terminal P1. When the laser is turned on, a voltage drop occurs across the resistor according to Ohm's law, and the voltage at the common node changes synchronously with the pulse current: when the laser is turned on, the peak current is at... A voltage drop of approximately 0.3V is generated across the resistor, and the common node voltage is approximately 0.3V; when the laser is turned off, the current drops to near zero, pulling down the resistor. The residual charge at the common node is discharged to ground, and the node voltage drops back to 0V, thereby forming a pulsed voltage signal synchronized with the pulsed laser.

[0064] At the common node, most of the pulsed photocurrent enters the anode of rectifier diode D1. After being unidirectionally turned on by rectifier diode D1, it flows out from the cathode and reaches the energy storage capacitor bank for charging and discharging. During the laser conduction phase, the current charges the main energy storage capacitor C1 and the high-frequency decoupling capacitor C2, and the output voltage rises. During the laser turn-off phase, the main energy storage capacitor C1 discharges to maintain the voltage, and after smoothing and filtering, a stable DC voltage of about 3V is formed at the energy output terminal. Finally, the energy flows to the energy output end to supply the external load RL, and is also equipped with terminal block P3.

[0065] The pulse voltage signal is directly input to the non-inverting input (port 1) of voltage comparator U1 at the common node, resulting in a stable DC voltage at the energy output terminal. The voltage is divided by the first and second voltage divider resistors connected in series, generating a reference voltage of approximately 0.16V at the midpoint between the two resistors. This reference voltage is compared with the stable DC voltage. The voltage comparator U1 inputs two voltages in a fixed ratio to the inverting input (port 3) of the voltage comparator. When the voltage at the non-inverting input is higher than the reference voltage, the internal output transistor is cut off, and the output (port 4) is pulled up by a resistor. Pull up to stable DC voltage When the voltage at the non-inverting input is lower than the reference voltage, the internal output transistor turns on, pulling the output terminal close to ground potential, resulting in a low-level output. Finally, the voltage comparator U1 outputs a digitally demodulated signal perfectly synchronized with the incident pulsed laser. The high level is approximately 3V, and the low level is approximately 0V. It can be directly connected to subsequent digital circuits through the terminal P2.

[0066] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A power transmission circuit based on laser photovoltaic cells, characterized in that, Includes laser photovoltaic cells, current sensing resistors, rectifier diodes, energy storage capacitor banks, first voltage divider resistors, second voltage divider resistors, pull-up resistors, pull-down resistors, and voltage comparators: The laser photovoltaic cell is used to receive externally incident pulsed modulated laser light and convert optical energy into pulsed photocurrent. The first end of the current sensing resistor is connected to the positive output terminal of the laser photovoltaic cell, and the second end forms a common node; When the pulsed photocurrent flows through the current sensing resistor, a corresponding pulsed voltage signal is generated at the common node; The common nodes are respectively connected to the energy branch and the signal branch; In the energy branch, the pulsed photocurrent output by the common node flows through the rectifier diode and is then input to the energy storage capacitor bank; the connection node between the cathode of the rectifier diode and the energy storage capacitor bank is the energy output terminal; after being smoothed and filtered by the energy storage capacitor bank, the pulsed photocurrent forms a stable DC voltage at the energy output terminal, which is used to supply power to the external load. In the signal branch, the pull-down resistor is connected between the common node and the reference ground; the pulse voltage signal is input to the non-inverting input of the voltage comparator through the common node; the stable DC voltage is divided by the first and second voltage divider resistors connected in series to generate a reference voltage, which is proportional to the stable DC voltage and is input to the inverting input of the voltage comparator; the stable DC voltage is connected to the power supply of the voltage comparator for power supply; the voltage comparator has an open-drain output structure, and the output of the voltage comparator is pulled up to the stable DC voltage through the pull-up resistor, outputting a digital demodulated signal corresponding to the pulse-modulated laser.

2. The simultaneous transmission circuit according to claim 1, characterized in that: The peak operating voltage of the laser photovoltaic cell Less than its maximum power point voltage This ensures that the laser photovoltaic cell remains in a near constant current region throughout the entire operating cycle; The peak operating voltage The following relationship must be satisfied: ； in, This is the highest charging voltage of the energy storage capacitor bank. The forward voltage drop of the rectifier diode is... The peak value of the pulsed photocurrent. The resistance value of the current sensing resistor.

3. The simultaneous transmission circuit according to claim 1, characterized in that: The resistance of the current sensing resistor is .

4. The simultaneous transmission circuit according to claim 1, characterized in that: The rectifier diode is a Schottky rectifier diode, and when the forward current is 0.3A, the forward voltage drop is no greater than 0.35V.

5. The simultaneous transmission circuit according to claim 1, characterized in that: The energy storage capacitor bank includes a main energy storage capacitor, the capacity of which is configured to reduce the steady-state output ripple rate of the energy branch to less than 10%.

6. The simultaneous transmission circuit according to claim 5, characterized in that: The energy storage capacitor bank also includes a high-frequency decoupling capacitor, and the main energy storage capacitor and the high-frequency decoupling capacitor are connected in parallel.

7. The simultaneous transmission circuit according to claim 1, characterized in that: The propagation delay of the voltage comparator is no greater than [amount missing]. The total propagation delay of the signal branch is less than It can fully track the digital demodulated signal at 1 kHz and below.

8. A simultaneous energy and information transmission system based on laser photovoltaic cells, characterized in that, Includes a pulsed laser emitting module and a signal transmission circuit as described in any one of claims 1 to 7: The pulsed laser emitting module is used to output the pulsed modulated laser; The simultaneous transmission circuit serves as a receiver, used to receive the pulse-modulated laser and synchronously output the stable DC voltage and the digital demodulated signal.

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