A power supply system of an electronic paper display and an electronic paper display device

Abstract

This invention discloses a power supply system and an electronic paper display device for an electronic paper display, relating to the field of power supply technology. It converts ambient light energy into electrical energy through an integrated power-generating glass and uses a step-up / step-down circuit to charge the energy storage element. The control module dynamically adjusts the step-up / step-down circuit using a maximum power point tracking algorithm to ensure the power-generating glass operates at its maximum power point, maximizing light energy collection. Simultaneously, it uses the operating current as feedback for closed-loop current control, ensuring stable and efficient charging. Therefore, the power supply system of this application continuously utilizes ambient light to replenish energy while the electronic paper display is operating normally, preventing the energy storage element from being depleted. It achieves energy balance without external charging and supports long-term continuous outdoor operation.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, and in particular to a power supply system and an electronic paper display device for an electronic paper display. Background Technology

[0002] Existing electronic paper displays, when used in outdoor applications, typically rely on internal energy storage components (such as batteries) for power. When the system operates for extended periods in environments without external power, the energy storage components gradually deplete until they are completely exhausted. At this point, the circuit immediately stops working, and the electronic paper display can no longer refresh or display information. Users must charge the energy storage components for an extended period before the system can resume normal operation. This "use and stop" and "long charging" model makes it difficult for electronic paper displays to achieve continuous, maintenance-free operation outdoors, severely limiting their application and promotion in scenarios without mains power or where wiring is difficult. Summary of the Invention

[0003] The purpose of this invention is to provide a power supply system and electronic paper display device for an electronic paper display, which continuously utilizes ambient light to replenish energy while the electronic paper display is working normally, avoids the depletion of energy storage components, achieves energy balance without external charging, and supports long-term continuous outdoor operation.

[0004] In a first aspect, this application provides a power supply system for an electronic paper display, comprising: At least one piece of power-generating glass is used to convert light energy into electrical energy; An energy storage element, the output of which is connected to the power supply terminal of the electronic paper display, is used to power the electronic paper display; A step-up / step-down circuit, whose input terminal is connected to the output terminal of the power-generating glass and whose output terminal is connected to the energy storage element, is used to step up or step down the voltage output by the power-generating glass to charge the energy storage element. The control module, whose output terminal is connected to the control terminal of the step-up / step-down circuit, is used to adjust the step-up / step-down circuit according to the electrical parameters of the power-generating glass and the operating current parameters of the step-up / step-down circuit through a maximum power point tracking algorithm, and to perform current closed-loop control with the operating current parameters of the step-up / step-down circuit as feedback, so that the power-generating glass operates at the maximum power point.

[0005] Optionally, the buck-boost circuit includes a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, and an inductor; The first end of the first switching transistor is connected to the output end of the power-generating glass. The second end of the first switching transistor is connected to the first end of the second switching transistor and the first end of the inductor. The second end of the second switching transistor is grounded. The first end of the third switching transistor is connected to the input end of the energy storage element. The second end of the third switching transistor is connected to the first end of the fourth switching transistor and the second end of the inductor. The second end of the fourth switching transistor is grounded. The control ends of the four switching transistors are all connected to the output end of the control module.

[0006] Optionally, the control module includes a processor and a switching power supply main controller; The processor is used to adjust the buck-boost circuit according to the electrical parameters of the power-generating glass and the operating current parameters of the buck-boost circuit through a maximum power point tracking algorithm, and to perform current closed-loop control with the operating current parameters as feedback to generate a control signal. The main controller of the switching power supply is connected to the control terminals of the processor and each switching transistor in the buck-boost circuit, respectively, and is used to convert the control signal into a drive signal and output it to each switching transistor in the buck-boost circuit.

[0007] Optional, also includes: A voltage sampling circuit is used to collect the voltage at the output terminal of the power-generating glass and transmit it to the processor; A current sampling circuit is used to collect the current at the output terminal of the power generation glass and transmit it to the main control of the switching power supply. The main controller of the switching power supply is also used to convert the current from an analog quantity to a digital quantity and transmit it to the processor.

[0008] Optionally, the buck-boost circuit is adjusted using a maximum power point tracking algorithm based on the electrical parameters of the power-generating glass and the operating current parameters of the buck-boost circuit, including: By adding a perturbation, the first power at the first moment before the perturbation and the second power at the second moment after the perturbation are compared, as well as the first voltage at the first moment and the second voltage at the second moment; Based on the first power, the second power, the first voltage, and the second voltage, a reference voltage for the voltage loop at the next moment of the second moment is determined, and a control signal is generated based on the reference voltage to adjust the duty cycle of the buck-boost circuit.

[0009] Optionally, determining the reference voltage of the voltage loop at the next time step after the second time step, based on the first power, the second power, the first voltage, and the second voltage, includes: If the second power is greater than the first power and the second voltage is greater than the first voltage, or if the second power is less than or equal to the first power and the second voltage is less than the first voltage, the reference voltage at the next moment is determined to be the sum of the reference voltage at the second moment and the preset voltage step size.

[0010] Optionally, determining the reference voltage of the voltage loop at the next time step after the second time step, based on the first power, the second power, the first voltage, and the second voltage, includes: If the second power is greater than the first power and the second voltage is less than or equal to the first voltage, or if the second power is less than or equal to the first power and the second voltage is greater than or equal to the first voltage, the reference voltage at the next moment is determined to be the difference between the reference voltage at the second moment and the preset voltage step size.

[0011] Optionally, the control module is also used to cumulatively record the charging amount of the power-generating glass and the consumption amount of the electronic paper display within a preset time period. When the difference between the cumulative consumption amount and the cumulative charging amount exceeds a preset threshold, the refresh rate of the electronic paper display is reduced or the electronic paper display is put into a low-power mode.

[0012] Optionally, the power-generating glass is disposed on the back of the electronic paper display, and the light-receiving surface of the power-generating glass faces the same direction as the display surface of the electronic paper display, and the back is opposite to the display surface of the electronic paper display.

[0013] Secondly, this application provides an electronic paper display device, including an electronic paper display and a power supply system for the electronic paper display as described above; the power supply system for the electronic paper display is used to provide operating power to the electronic paper display.

[0014] This invention provides a power supply system and device for an electronic paper display, relating to the field of power supply technology. It integrates a power-generating glass to convert ambient light energy into electrical energy and incorporates a step-up / step-down circuit to charge the energy storage element. The control module dynamically adjusts the step-up / step-down circuit using a maximum power point tracking algorithm to ensure the power-generating glass operates at its maximum power point, maximizing light energy collection. Simultaneously, it uses the operating current as feedback for closed-loop current control, ensuring stable and efficient charging. Therefore, this power supply system continuously utilizes ambient light to replenish energy while the electronic paper display operates normally, preventing the energy storage element from being depleted. It achieves energy balance without external charging and supports long-term continuous outdoor operation. Attached Figure Description

[0015] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of a power supply system for an electronic paper display provided by the present invention; Figure 2 This is a schematic diagram of the bonding position of a power-generating glass provided by the present invention; Figure 3 This is a schematic diagram of a maximum power point tracking control provided by the present invention; Figure 4 A schematic diagram of a charging current curve provided by the present invention; Figure 5 This is a schematic diagram of a charging voltage curve provided by the present invention. Detailed Implementation

[0017] The core of this invention is to provide a power supply system and an electronic paper display device for an electronic paper display, which continuously utilizes ambient light to supplement energy while the electronic paper display is working normally, thus avoiding the depletion of energy storage components.

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0019] like Figure 1 In a first aspect, this application provides a power supply system for an electronic paper display, comprising: At least one piece of power-generating glass 1 is used to convert light energy into electrical energy; The energy storage element 5 has its output terminal connected to the power supply terminal of the electronic paper display to power the electronic paper display. The step-up / step-down circuit 2 has its input terminal connected to the output terminal of the power generation glass 1 and its output terminal connected to the energy storage element 5. It is used to step up or step down the voltage output by the power generation glass 1 to charge the energy storage element 5. The control module, whose output is connected to the control terminal of the step-up / step-down circuit 2, is used to adjust the step-up / step-down circuit 2 according to the electrical parameters of the power generation glass 1 and the operating current parameters of the step-up / step-down circuit 2 through the maximum power point tracking algorithm, and to perform current closed-loop control with the operating current parameters of the step-up / step-down circuit 2 as feedback, so that the power generation glass 1 operates at the maximum power point.

[0020] In this embodiment, the power-generating glass 1 converts light energy into electrical energy, and the voltage and current change with the light intensity. The energy storage element 5 receives the electrical energy output from the buck-boost circuit 2, providing continuous power to the electronic paper display, which may be, but is not limited to, a cholesteric electronic paper display. In practical applications, when the light intensity is strong, the voltage output by the power-generating glass 1 may be higher than the charging voltage of the energy storage element 5. In this case, the buck-boost circuit 2 can operate in buck mode, converting the excess voltage into a voltage range suitable for the energy storage element 5. When the light intensity is weak, causing the output voltage of the power-generating glass 1 to be lower than the voltage of the energy storage element 5, the buck-boost circuit 2 can operate in boost mode, increasing the input voltage to an acceptable range for the energy storage element 5, thereby ensuring that the energy storage element 5 can be continuously charged and maintaining the normal operation of the electronic paper display.

[0021] Under the control module, the instantaneous power can be calculated based on the voltage and current signals of the power-generating glass 1. The duty cycle of the buck-boost circuit 2 is adjusted using a maximum power point tracking algorithm, ensuring that the power-generating glass 1 operates close to its maximum power point under different lighting conditions. In this embodiment, the control module uses the operating current of the buck-boost circuit 2 as feedback and adjusts the duty cycle through closed-loop control. This allows for rapid response to voltage and current fluctuations caused by changes in lighting conditions, thereby achieving dynamic adjustment of the output power of the power-generating glass 1. This ensures that the energy storage element 5 receives a stable charging current and does not experience power outages due to instantaneous changes in lighting.

[0022] In terms of implementation, a maximum power point tracking (MPPT) method based on perturbation observation can be adopted. This involves periodically adjusting the reference voltage of the power-generating glass 1 by small amplitude, comparing the power change before and after adjustment, determining the direction of adjustment, and updating the reference voltage, thereby ensuring that the power-generating glass 1 operates near its maximum power. Another implementation method is constant power point tracking (CPST). This involves measuring the illuminance and electrical parameters of the power-generating glass 1 in real time, calculating the target voltage using a preset power curve, and then adjusting the duty cycle of the step-up / step-down circuit 2 by the control module to make the output power of the power-generating glass 1 approach the target value. Both methods can ensure the charging stability of the energy storage element 5 through closed-loop current feedback.

[0023] Furthermore, the operating frequency and sampling frequency of the control module can be implemented differently in this embodiment. For example, in one approach, the control module collects voltage and current signals every few milliseconds and quickly adjusts the switching state of the buck-boost circuit 2; in another approach, a lower sampling frequency and a smoother duty cycle adjustment strategy can be used to minimize power output fluctuations, making it more suitable for applications with slow changes in lighting or large capacity energy storage components 5. These two approaches can be selected based on the actual usage environment to ensure continuous and stable power supply to the electronic paper display under various outdoor conditions.

[0024] like Figure 1 In a preferred embodiment, the buck-boost circuit 2 includes a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, and an inductor L1; The first terminal of the first switch Q1 is connected to the output terminal of the power generation glass 1. The second terminal of the first switch Q1 is connected to the first terminal of the second switch Q2 and the first terminal of the inductor L1. The second terminal of the second switch Q2 is grounded. The first terminal of the third switch Q3 is connected to the input terminal of the energy storage element 5. The second terminal of the third switch Q3 is connected to the first terminal of the fourth switch Q4 and the second terminal of the inductor L1. The second terminal of the fourth switch Q4 is grounded. The control terminals of the four switches are all connected to the output terminal of the control module.

[0025] In this embodiment, four switching transistors and inductor L1 form the energy transfer unit of the buck-boost circuit 2. The first switching transistor Q1 and the second switching transistor Q2 on the left bridge arm control the transfer of the input voltage to inductor L1. When the first switching transistor Q1 is turned on, inductor L1 begins to store energy; when the second switching transistor Q2 is turned on, inductor L1 releases energy, converting the input voltage and outputting it to the right bridge arm. The third switching transistor Q3 and the fourth switching transistor Q4 on the right bridge arm can adjust the output voltage according to the load voltage and the voltage of the energy storage element 5. Inductor L1 acts as an energy buffer and current smoother between the two bridge arms, ensuring smooth current changes without significant fluctuations. The control module controls the duty cycle and turn-on sequence of the four switching transistors to achieve smooth switching of the input voltage between boost and buck modes, enabling the energy storage element 5 to obtain suitable charging voltage and current.

[0026] In one implementation, the duty cycle of the left and right bridge arm switches can be continuously adjusted by the control module to maintain stable energy transfer under high or low input voltage conditions, thereby meeting the charging requirements of the energy storage element 5 under different lighting conditions. In another implementation, the left bridge arm can operate in intermittent energy storage mode, that is, the first switch Q1 is intermittently turned on to allow the inductor L1 to store energy, while the right bridge arm maintains continuous output, making the energy storage current relatively constant, which is suitable for outdoor environments with large variations in lighting. Both methods utilize the energy storage of the inductor L1 and the switching of the switches to achieve dynamic matching of the voltage of the power generation glass 1 to the energy storage element 5. At the same time, closed-loop control ensures stable charging current, preventing power interruption or current overshoot due to lighting fluctuations.

[0027] In this embodiment, the buck-boost circuit 2 can switch its operating mode according to the relationship between the output voltage of the power-generating glass 1 and the voltage of the energy storage element 5. It can operate in buck mode or boost mode. In buck mode, when the input voltage is higher than the voltage of the energy storage element 5, the excess voltage is converted to a level suitable for the energy storage element 5 through the left bridge arm and inductor L1. In boost mode, when the input voltage is lower than the voltage of the energy storage element 5, the voltage is boosted to an acceptable range for the energy storage element 5 through bridge arm control and energy storage by inductor L1. In this way, the buck-boost circuit 2 of this embodiment can adapt to a wide range of input voltage changes. It is easy to understand that it can ensure the charging stability of the energy storage element 5 under different light intensities, while maintaining the normal operation of the electronic paper display.

[0028] In a preferred embodiment, the control module includes a processor 4 and a switching power supply main controller 3; The processor 4 is used to adjust the step-up / step-down circuit 2 according to the electrical parameters of the power generation glass 1 and the operating current parameters of the step-up / step-down circuit 2 through the maximum power point tracking algorithm, and to perform current closed-loop control with the operating current parameters as feedback quantity to generate control signals. The main control unit 3 of the switching power supply is connected to the control terminals of each switching transistor in the processor 4 and the buck-boost circuit 2, respectively, and is used to convert the control signal into a drive signal and output it to each switching transistor in the buck-boost circuit 2.

[0029] In this embodiment, the control module is divided into two parts: processor 4 and switching power supply main controller 3. Processor 4 is used to collect the voltage and current signals of the power-generating glass 1 and calculate the input power based on the operating current parameters of the buck-boost circuit 2. Through the maximum power point tracking algorithm, processor 4 can determine the current optimal operating point of the power-generating glass 1 and generate adjustment signals to control the duty cycle and conduction timing of the buck-boost circuit 2, so that the power-generating glass 1 outputs electrical energy close to its maximum power under different illumination conditions. At the same time, processor 4 uses the operating current of the buck-boost circuit 2 as feedback and continuously corrects the duty cycle through closed-loop control to ensure that the energy storage element 5 obtains a stable charging current, avoiding current overshoot or interruption caused by illumination fluctuations.

[0030] In one implementation, processor 4 can be an MCU (Microcontroller Unit) that periodically samples voltage and current signals, executes a maximum power point tracking algorithm, and outputs control signals to the main control unit 3 of the switching power supply. In another implementation, processor 4 can integrate analog and digital hybrid control functions, filtering and adjusting the signal gain before directly calculating control parameters and transmitting them to the main control unit 3. This generates drive signals that are output to the various switches in the buck-boost circuit 2, enabling dynamic duty cycle adjustment.

[0031] The main control unit 3 of the switching power supply receives the control signal output from the processor 4, converts it into a drive signal suitable for the switching transistors, and outputs it to each switching transistor in the buck-boost circuit 2. In this way, the conduction timing and duty cycle of each switching transistor can be controlled, allowing for smooth switching of the input voltage between boost and buck modes, while maintaining the charging stability of the energy storage element 5 and the continuous power supply to the electronic paper display. In different implementations, the main control unit 3 can achieve high-frequency or low-frequency switching to adapt to different lighting conditions and energy storage requirements. The main control unit 3 can also select appropriate drive voltage and current based on the type of switching transistor (e.g., MOSFET or IGBT). Dead-time control can also be added internally to the main control unit 3 to prevent short circuits caused by simultaneous conduction of two switching transistors. The processor 4 and the main control unit 3 communicate via a standard GPIO (General-purpose input / output) port or a dedicated PWM (Pulse Width Modulation) interface. Upon receiving a signal, the main control unit 3 directly outputs it to the gate of each switching transistor.

[0032] As a preferred embodiment, it also includes: A voltage sampling circuit is used to collect the voltage at the output terminal of the power generation glass 1 and transmit it to the processor 4; The current sampling circuit is used to collect the current at the output terminal of the power generation glass 1 and transmit it to the main control unit of the switching power supply 3; The main control unit 3 of the switching power supply is also used to convert the current from an analog quantity to a digital quantity and transmit it to the processor 4.

[0033] In this embodiment, the voltage sampling circuit is used to collect the voltage signal at the output terminal of the power generation glass 1 (e.g., Figure 1 The voltage is sampled by the IIN (indicated by the voltage sensor), and the collected voltage is transmitted to the processor 4. The processor 4 determines the working state of the power-generating glass 1 by reading the voltage signal, and adjusts the duty cycle and conduction timing of the buck-boost circuit 2 in conjunction with the maximum power point tracking algorithm, thereby enabling the power-generating glass 1 to output electrical energy close to its maximum power under different lighting conditions. In one implementation, the voltage sampling circuit can use two resistors in series. One end of the series connection is connected to the output terminal of the power-generating glass 1, and the other end is grounded. The middle end of the two resistors is connected to the processor 4, and a voltage signal suitable for the processor 4 to collect is obtained through voltage division (see details). Figure 1 (VIN in the text). This method is simple, low-cost, and suitable for powering electronic paper displays.

[0034] The current sampling circuit is used to acquire the output current signal of the power-generating glass 1 and transmit the signal to the main control unit 3 of the switching power supply. The main control unit 3 converts the analog signal into a digital signal and then transmits it to the processor 4 to achieve closed-loop control and real-time adjustment of the duty cycle. In one implementation, the current sampling circuit can connect a sampling resistor in series between the buck-boost circuit 2 and the output terminal of the power-generating glass 1 (see details). Figure 1 R in SNS1 The sampling current is determined by the voltage difference between ISN1 (2) and ISP1 (2), where ISMON is the sampling current after conversion by the main control 3 of the switching power supply, and ICTRI is the control signal sent by the processor 4 to the main control 3 of the switching power supply. The current signal is obtained by measuring the voltage drop across the resistor. In another way, a current transformer or Hall current sensor can be used for non-contact sampling, which can avoid resistor heating or loss and is suitable for high current or high precision scenarios.

[0035] A capacitor C1 can also be set at the output end of the power generation glass 1, and a capacitor C2 can be set at the output end of the energy storage element 5 to achieve filtering or stabilization of the output voltage and input voltage.

[0036] By combining voltage and current sampling, processor 4 can acquire the electrical parameters of the power-generating glass 1 and the operating status of the step-up / step-down circuit 2 in real time. This allows for closed-loop control based on the maximum power point tracking algorithm, ensuring a stable charging current for the energy storage element 5 while maintaining continuous power supply to the electronic paper display. Under varying lighting conditions and load changes, this sampling scheme can flexibly select different implementation methods to adapt to practical application requirements.

[0037] like Figure 3In a preferred embodiment, the step-up / step-down circuit 2 is adjusted using a maximum power point tracking algorithm based on the electrical parameters of the power-generating glass 1 and the operating current parameters of the step-up / step-down circuit 2, including: By adding a perturbation, the first power at the first moment before the perturbation and the second power at the second moment after the perturbation, as well as the first voltage at the first moment and the second voltage at the second moment, are compared. Based on the first power, the second power, the first voltage, and the second voltage, the reference voltage of the voltage loop at the next moment of the second moment is determined, and a control signal is generated based on the reference voltage to adjust the duty cycle of the buck-boost circuit 2.

[0038] In this embodiment, the processor 4 periodically adds small-amplitude disturbances based on the electrical parameters of the power-generating glass 1 and the operating current parameters of the buck-boost circuit 2. Specifically, the control module first records the output voltage and current of the power-generating glass 1 at the current moment and calculates the first power at the first moment. Then, the control module actively introduces a disturbance into the buck-boost circuit 2, such as increasing the duty cycle slightly. After the disturbance, once the circuit stabilizes, the voltage and current at the second moment are collected, and the second power is calculated. By comparing the power and voltage at these two moments, it can be determined whether the disturbance increased or decreased the output power of the power-generating glass 1.

[0039] The next adjustment is determined based on the comparison results. If the power increases, it means the previous disturbance direction was correct, and the reference voltage is changed in the same direction in the next step. If the power decreases, it means the direction is wrong, and the reference voltage is changed in the opposite direction in the next step. It is important to understand that simply looking at the power change is not enough; voltage changes must also be considered. For example, in the case of a sudden increase in light intensity, the power may increase due to environmental changes, not because of the disturbance. This embodiment also considers voltage changes, which can distinguish between power changes caused by disturbances and power changes caused by external light, thus avoiding misjudgment.

[0040] The judgment result is converted into a voltage loop reference voltage for the next moment. The control module has an internal voltage loop that adjusts the duty cycle of the boost / buck circuit 2 based on this reference voltage. The reference voltage increases or decreases by a preset step size each time. This step size can be, but is not limited to, one percent of the open-circuit voltage of the power-generating glass 1, or a fixed voltage value such as 0.1 volts. A step size that is too large can easily cause oscillations around the maximum power point, while a step size that is too small results in slow tracking speed. This embodiment, through repeated perturbation and judgment, gradually approaches the optimal operating voltage corresponding to the maximum power point of the power-generating glass 1 under the current illumination.

[0041] In one implementation, the perturbation amplitude and frequency can be set according to the rate of change of light intensity. For example, a smaller perturbation amplitude and lower frequency are used when the light intensity changes slowly, while a larger perturbation amplitude and higher frequency are used when the light intensity changes rapidly. In this way, this embodiment can dynamically adjust the power generation glass 1 under different environments while ensuring stable charging of the energy storage element 5.

[0042] As a preferred embodiment, determining the reference voltage of the voltage loop for the next time step after the second time step, based on the first power, the second power, the first voltage, and the second voltage, includes: If the second power is greater than the first power and the second voltage is greater than the first voltage, or if the second power is less than or equal to the first power and the second voltage is less than the first voltage, the reference voltage at the next moment is determined to be the sum of the reference voltage at the second moment and the preset voltage step size.

[0043] This embodiment presents a specific judgment rule in the perturbation observation method. In the first case, if the second power is greater than the first power, it indicates that the power increased after the perturbation. Simultaneously, if the second voltage is greater than the first voltage, it means the perturbation direction increased the voltage. Since both power and voltage increased, the perturbation in the direction of increasing voltage was correct, so the reference voltage should continue to increase in the next moment. In the second case, if the second power is less than or equal to the first power, it indicates that the power did not increase or even decreased after the perturbation. Simultaneously, if the second voltage is less than the first voltage, it means the perturbation caused the voltage to decrease. Since both power and voltage decreased, the direction of voltage decrease was incorrect, and it should be reversed, meaning the reference voltage should be increased in the next moment. Both cases lead to the same conclusion: the reference voltage should increase in the next moment.

[0044] Specifically, the change in the reference voltage is based on the reference voltage at the second moment plus a preset step size. The reference voltage at the second moment is the voltage reference value after the disturbance. The control module stores the reference voltage at the second moment, then adds the step size to obtain the new reference voltage to be used at the next moment. This embodiment does not limit whether the step size is fixed. One implementation method is to use a fixed step size, which is simple and reliable. Another implementation method is to dynamically adjust the step size according to the magnitude of the power change. For example, when the power change is large, a large step size is used to quickly approach the maximum power point, and when the power change is small, a small step size is used for fine positioning to avoid oscillation.

[0045] This embodiment also includes an equality condition in the judgment criteria when the second power is less than or equal to the first power. That is, if the power remains unchanged after the disturbance, it is considered that the power has not increased, and the system is treated as if the voltage has increased. This avoids the system switching directions back and forth near the maximum power point. When the actual power is already close to the maximum value, the disturbance may cause a very small power change or even no change. According to the rules of this embodiment, the system will continue to fine-tune in the same direction until the power begins to decrease, and then another judgment rule will pull it back.

[0046] As a preferred embodiment, determining the reference voltage of the voltage loop for the next time step after the second time step, based on the first power, the second power, the first voltage, and the second voltage, includes: If the second power is greater than the first power and the second voltage is less than or equal to the first voltage, or if the second power is less than or equal to the first power and the second voltage is greater than or equal to the first voltage, the reference voltage at the next moment is determined to be the difference between the reference voltage at the second moment and the preset voltage step size.

[0047] This embodiment presents another judgment rule in the perturbation observation method. In the first case, if the second power is greater than the first power, it indicates that the power increased after the perturbation, but the second voltage is less than or equal to the first voltage, meaning the perturbation direction lowered the voltage. Since the power increased while the voltage decreased, the perturbation in the direction of voltage decrease was correct, so the reference voltage should continue to decrease in the next moment. In the second case, if the second power is less than or equal to the first power, it indicates that the power did not increase after the perturbation, and the second voltage is greater than or equal to the first voltage, meaning the perturbation increased the voltage. The power decreased while the voltage increased, indicating the voltage increase direction was incorrect; it should be reversed, meaning the reference voltage should be decreased in the next moment. Both cases lead to the same conclusion: the reference voltage should decrease in the next moment.

[0048] This embodiment is used in conjunction with the previous embodiment. The previous embodiment dealt with the case where the reference voltage needed to be increased, while this embodiment deals with the case where the reference voltage needed to be decreased. After each round of sampling, the control module will only enter the judgment logic of one of the embodiments based on the comparison results of power and voltage. If the condition for increasing the reference voltage is met, the addition rule of the previous embodiment is executed. If the condition for decreasing the reference voltage is met, the subtraction rule of this embodiment is executed. The two rules together form a complete disturbance observation method closed loop.

[0049] In this embodiment, the reduction of the reference voltage is based on subtracting a preset step size from the reference voltage at the second moment. This preset step size can be the same as or different from the step size in the previous embodiment. One implementation is to take the same fixed value for the two step sizes, which is convenient for implementation. Another implementation is to set the step size for increasing and the step size for decreasing separately. For example, when the power drops sharply, a larger step size for decreasing is used to quickly callback and prevent the system from deviating too far. This embodiment does not limit the specific way of taking the step size, as long as the control module can adjust the reference voltage according to the judgment result to make the operating point of the power generation glass 1 converge to the maximum power point.

[0050] The specific process corresponding to the perturbation observation method can be referred to Figure 3 , first measure the voltage U(k) and current I(k) at the second moment, calculate the second power P(k)=U(k)×I(k), and compare the second power with the first power P(k - 1) at the first moment: If P(k)=P(k - 1), keep the current operating point unchanged; If P(k)>P(k - 1) and U(k)>U(k - 1), it means the voltage increase direction is correct, continue to increase Uret, that is, make Uret = Uret + △U. If P(k)>P(k - 1) and U(k)<U(k - 1), it means the voltage decrease direction is correct, continue to decrease Uret, that is, make Uret = Uret - △U. If P(k)<P(k - 1), it means the voltage increase direction is incorrect, and Uret needs to be adjusted in the reverse direction. Specifically, if U(k)<U(k - 1), let Uret = Uret + △U, if U(k)>U(k - 1), let Uret = Uret - △U, where Uret is the reference voltage of the voltage loop.

[0051] As a preferred embodiment, the control module is further configured to cumulatively record the charging amount of the power generation glass 1 and the consumption amount of the electronic paper display within a preset time period. When the difference between the cumulative consumption amount and the cumulative charging amount exceeds a preset threshold, the refresh frequency of the electronic paper display is reduced or it enters the low-power mode.

[0052] In this embodiment, in addition to adjusting the maximum power point tracking and current closed-loop of the power generation glass 1 in real time, the control module also performs energy accumulation. Specifically, the control module cumulatively records two accumulations within a period of time. One is the total amount of electricity charged into the energy storage element 5 by the power generation glass 1, and the other is the total amount of electricity consumed by the electronic paper display during the refresh and display processes. This period of time can be but is not limited to one day, several hours, or determined according to the light cycle.

[0053] This embodiment also sets a preset threshold. For example, if the energy consumption exceeds the charging amount by a certain value, it indicates that the power replenished by the power-generating glass 1 is insufficient during this period, and the energy storage element 5 is being overdrawn. Once the difference between the cumulative consumption and the cumulative charging amount exceeds this threshold, the control module takes power-saving measures. One approach is to reduce the refresh rate of the electronic paper display, for example, changing it from refreshing once per minute to refreshing once every five minutes; another approach is to directly put the electronic paper display into a low-power mode, such as displaying only key information and turning off unnecessary communication or backlighting. These two approaches can be used individually or in combination. Through this energy management, the over-consumption of the energy storage element 5 can be prevented, and the power-generating glass 1 can replenish the depleted power when the light returns, thereby maintaining energy balance over a longer time scale.

[0054] like Figure 2 In a preferred embodiment, the power-generating glass 1 is disposed on the back of the electronic paper display, and the light-receiving surface of the power-generating glass 1 faces the same direction as the display surface of the electronic paper display, while the back is opposite to the display surface of the electronic paper display. Figure 2 In the middle, the right side of the power-generating glass 1 is the electronic paper display, the left side of the electronic paper display (that is, the side closer to the power-generating glass 1) is the back of the screen of the electronic paper display, and the right side of the electronic paper display (that is, the side closer to the power-generating glass 1) is the display surface of the electronic paper display.

[0055] In this embodiment, the power-generating glass 1 is arranged on the back of the electronic paper display, with the light-receiving surface and the display surface facing the same direction. This allows light to directly illuminate the power-generating glass 1 to generate electricity without affecting the display effect of the electronic paper display. This arrangement allows for full utilization of sunlight in outdoor environments, efficiently converting light energy into electrical energy to charge the energy storage element 5 and maintain power supply to the display.

[0056] Furthermore, the rear position allows for easy installation of mounting brackets or protective devices, thus protecting the power-generating glass 1 from mechanical damage or dust obstruction. In practical applications, the tilt angle or position of the power-generating glass 1 can be adjusted according to the installation environment and lighting angle to ensure more uniform light incidence, stable power generation, and normal display and long-term operation of the electronic paper display.

[0057] Optionally, a light intensity detection unit may be included to detect ambient light intensity; the maximum power point tracking (MPPT) control unit selectively enables or disables the MPPT algorithm based on the detection results from the light intensity detection unit. For example, when the light intensity is below a preset threshold (such as at night or on a cloudy day), the output power of the power-generating glass 1 is extremely low, and the continuous operation of the MPPT algorithm will consume the power of the energy storage element 5. At this time, the MPPT algorithm can be disabled, allowing the system to enter a low-power sleep mode, or switch to a timed wake-up mode.

[0058] Optionally, it may also include a power monitoring unit for monitoring the remaining power of the energy storage element 5; the system adjusts the image refresh rate of the electronic paper display based on the remaining power when it is below a minimum threshold.

[0059] In a set of comparative tests, an outdoor unit (i.e., a conventional e-paper display) without a power-generating glass was placed in an outdoor environment and operated continuously for 24 hours at a refresh rate of 120 seconds. The test results showed that the discharge curve of its 12V / 5000mA energy storage element exhibited a continuous downward trend. The voltage decreased slowly as the operating time increased, the energy was gradually depleted, and eventually the system stopped working. External charging of the energy storage element was required to restore operation.

[0060] In comparison, the same outdoor unit equipped with the power-generating glass was placed in the same environment and operated continuously for 24 hours at the same refresh rate (once every 120 seconds). This unit utilizes power-generating glass in conjunction with a DC-DC (including MPPT) Buck-Boost architecture charging and power management hardware and software control system. Test results show that the discharge curve of the energy storage element exhibits a slow upward trend, with the voltage gradually increasing as the operating time extends, indicating a slow accumulation of electrical energy. After 24 hours of operation, the ending voltage was not lower than the starting voltage, indicating that the electrical energy consumed during the refresh process was replenished by the power-generating glass within the same period, with some remaining. Therefore, the power supply system provided in this application enables the electronic paper display to operate continuously outdoors for extended periods without additional power.

[0061] like Figure 4 , Figure 4 The charging curve is shown at a setting of 12V / 350mA. For example... Figure 5 As shown, the battery voltage of the unit equipped with this power supply system remains stable or rises slowly during continuous operation, while the comparative unit without this system experiences a continuous drop in voltage until it stops working.

[0062] It should be noted that the preset operating mode refers to a pre-defined typical operating scenario, such as a bus stop sign that refreshes its image every 120 seconds. In this scenario, the average power consumption of the cholesteric electronic paper display is fixed.

[0063] Optionally, a wireless communication module is also included. This module is connected to the power management and control module and is used to send the power generation status of the power-generating glass 1, the power status of the energy storage element 5, and the operating status of the load to a remote server or user terminal. This enables remote operation and maintenance management of outdoor information terminals, significantly reducing the cost of manual inspections, and timely detection of abnormal states (such as the power-generating glass 1 being blocked or the energy storage element 5 aging), providing early warnings.

[0064] Preferably, the power-generating glass 1 is a double-sided power-generating glass 1, with its front side used to collect direct ambient light and its back side used to collect reflected ambient light. This increases the energy collection density per unit area, allowing more electrical energy to be obtained under the same lighting conditions. Under cloudy or overcast conditions, the proportion of diffuse reflected light increases, resulting in a more significant power generation gain on the back side. This further reduces the capacity requirement of the energy storage element 5, thereby reducing the overall size and cost of the device.

[0065] Secondly, this application provides an electronic paper display device, including an electronic paper display and a power supply system for the electronic paper display as described above; the power supply system for the electronic paper display is used to provide operating power to the electronic paper display.

[0066] For a description of the electronic paper display device, please refer to the description of the power supply system of the electronic paper display above; this application will not repeat it here.

[0067] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0068] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power supply system for an electronic paper display, characterized in that, include: At least one piece of power-generating glass is used to convert light energy into electrical energy; An energy storage element, the output of which is connected to the power supply terminal of the electronic paper display, is used to power the electronic paper display; A step-up / step-down circuit, whose input terminal is connected to the output terminal of the power-generating glass and whose output terminal is connected to the energy storage element, is used to step up or step down the voltage output by the power-generating glass to charge the energy storage element. The control module, whose output terminal is connected to the control terminal of the step-up / step-down circuit, is used to adjust the step-up / step-down circuit according to the electrical parameters of the power-generating glass and the operating current parameters of the step-up / step-down circuit through a maximum power point tracking algorithm, and to perform current closed-loop control with the operating current parameters of the step-up / step-down circuit as feedback, so that the power-generating glass operates at the maximum power point.

2. The power supply system for the electronic paper display as described in claim 1, characterized in that, The buck-boost circuit includes a first switch, a second switch, a third switch, a fourth switch, and an inductor; The first terminal of the first switching transistor is connected to the output terminal of the power-generating glass. The second terminal of the first switching transistor is connected to the first terminal of the second switching transistor and the first terminal of the inductor. The second terminal of the second switching transistor is grounded. The first terminal of the third switching transistor is connected to the input terminal of the energy storage element. The second terminal of the third switching transistor is connected to the first terminal of the fourth switching transistor and the second terminal of the inductor. The second terminal of the fourth switching transistor is grounded. The control terminals of the four switching transistors are all connected to the output terminal of the control module.

3. The power supply system for the electronic paper display as described in claim 1, characterized in that, The control module includes a processor and a switching power supply main controller; The processor is used to adjust the buck-boost circuit according to the electrical parameters of the power-generating glass and the operating current parameters of the buck-boost circuit through a maximum power point tracking algorithm, and to perform current closed-loop control with the operating current parameters as feedback to generate a control signal. The main controller of the switching power supply is connected to the control terminals of the processor and each switching transistor in the buck-boost circuit, respectively, and is used to convert the control signal into a drive signal and output it to each switching transistor in the buck-boost circuit.

4. The power supply system for the electronic paper display as described in claim 3, characterized in that, Also includes: A voltage sampling circuit is used to collect the voltage at the output terminal of the power-generating glass and transmit it to the processor; A current sampling circuit is used to collect the current at the output terminal of the power-generating glass and transmit it to the main control of the switching power supply. The main controller of the switching power supply is also used to convert the current at the output terminal of the power-generating glass from an analog quantity to a digital quantity and transmit it to the processor.

5. The power supply system for the electronic paper display as described in claim 1, characterized in that, Based on the electrical parameters of the power-generating glass and the operating current parameters of the step-up / step-down circuit, the step-up / step-down circuit is adjusted using a maximum power point tracking algorithm, including: By adding a perturbation, the first power at the first moment before the perturbation and the second power at the second moment after the perturbation are compared, as well as the first voltage at the first moment and the second voltage at the second moment; Based on the first power, the second power, the first voltage, and the second voltage, a reference voltage for the voltage loop at the next moment of the second moment is determined, and a control signal is generated based on the reference voltage to adjust the duty cycle of the buck-boost circuit.

6. The power supply system for the electronic paper display as described in claim 5, characterized in that, Based on the first power, the second power, the first voltage, and the second voltage, determine the reference voltage of the voltage loop for the next time step at the second time step, including: If the second power is greater than the first power and the second voltage is greater than the first voltage, or if the second power is less than or equal to the first power and the second voltage is less than the first voltage, the reference voltage at the next moment is determined to be the sum of the reference voltage at the second moment and the preset voltage step size.

7. The power supply system for the electronic paper display as described in claim 5, characterized in that, Based on the first power, the second power, the first voltage, and the second voltage, determine the reference voltage of the voltage loop for the next time step at the second time step, including: If the second power is greater than the first power and the second voltage is less than or equal to the first voltage, or if the second power is less than or equal to the first power and the second voltage is greater than or equal to the first voltage, the reference voltage at the next moment is determined to be the difference between the reference voltage at the second moment and the preset voltage step size.

8. The power supply system for the electronic paper display as described in claim 1, characterized in that, The control module is also used to cumulatively record the charging amount of the power-generating glass and the consumption amount of the electronic paper display within a preset time period. When the difference between the cumulative consumption amount and the cumulative charging amount exceeds a preset threshold, the refresh rate of the electronic paper display is reduced or the electronic paper display is put into a low-power mode.

9. The power supply system for the electronic paper display as described in any one of claims 1-8, characterized in that, The power-generating glass is disposed on the back of the electronic paper display, and the light-receiving surface of the power-generating glass faces the same direction as the display surface of the electronic paper display, with the back being opposite to the display surface of the electronic paper display.

10. An electronic paper display device, characterized in that, The device includes an electronic paper display and a power supply system for the electronic paper display as described in any one of claims 1 to 9; the power supply system for the electronic paper display is used to provide operating power to the electronic paper display.

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