Photovoltaic power generation system performance enhancement system and method based on self-adaptive MPPT (Maximum Power Point Tracking) algorithm

Abstract

The invention relates to the technical field of photovoltaic power generation, in particular to a photovoltaic power generation system performance enhancing system and method based on a self-adaptive MPPT algorithm, through mutual cooperation of a photovoltaic panel battery, an MPPT controller, an inverter, a DC-DC converter, a logic control circuit and a storage battery, the working point of the photovoltaic panel battery is adjusted in real time by using the MPPT controller, and the performance of the photovoltaic power generation system is enhanced. The method comprises the following steps of: controlling a control algorithm module to ensure that the maximum power output is obtained under the current environmental condition, quickly responding to the change of illumination intensity and temperature through the control algorithm module, adjusting a working point to match the optimal power output, and automatically adjusting according to reduced illumination in cloudy or rainy weather, so as to continue to operate at the most efficient power point. Therefore, a high energy utilization rate can be kept under different weather conditions, real-time adjustment under different illumination and temperature adjustment is realized, and the overall power generation efficiency and the system stability are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic power generation, and in particular relates to a photovoltaic power generation system performance enhancement system and method based on an adaptive MPPT algorithm. Background Art

[0002] Photovoltaic power generation system mainly consists of photovoltaic panels, controllers, batteries and inverters. It uses the photovoltaic effect of photovoltaic cells to directly convert solar radiation into electrical energy. The core principle of photovoltaic power generation system is the photovoltaic effect, that is, when photons hit semiconductor materials, they can stimulate electrons and form current. This conversion process does not require the intermediate link of thermal energy, so it has extremely high energy conversion efficiency.

[0003] In order to capture solar energy to the greatest extent and convert it into solar energy, a photovoltaic power generation system performance enhancement system is usually used to improve power generation efficiency. However, a photovoltaic power generation system enhancement system is usually composed of photovoltaic panels, reflectors, inverters and batteries. Photovoltaic panels absorb solar radiation energy and convert it into electrical energy, and the inverter converts direct current into alternating current for home or industrial use.

[0004] However, since the current solar panels are not convenient for real-time adjustment of the maximum power point of the photovoltaic system under various light and temperature conditions, the efficiency of power generation is greatly affected by weather and geographical location, and the power generation efficiency will be significantly reduced on cloudy days and rainy seasons. Therefore, we need to propose a photovoltaic power generation system performance enhancement system and method based on an adaptive MPPT algorithm, so that it can adjust the maximum power point tracking of the photovoltaic system in real time to ensure that it can maintain the optimal operating state under various light and temperature conditions to improve its power generation efficiency. Summary of the invention

[0005] In view of the above problems, the present invention provides a photovoltaic power generation system performance enhancement system with an adaptive MPPT algorithm, including a photovoltaic panel battery for converting solar energy into electrical energy;

[0006] An MPPT controller electrically connected to the photovoltaic panel battery, the MPPT controller is used to adjust the working point of the photovoltaic panel battery in real time to achieve maximum power output, and the MPPT controller uses an adaptive algorithm to automatically adjust the working point according to the ambient light intensity, temperature and the current working state of the photovoltaic panel battery;

[0007] Inverter used to convert DC power into AC power for power grid or load;

[0008] A DC-DC converter connected between the MPPT controller and the inverter, the DC-DC converter being used to regulate voltage and current;

[0009] A battery connected in parallel with the inverter, the battery is used to store excess electrical energy and release it when needed;

[0010] A control algorithm module for implementing an adaptive MPPT algorithm and optimizing system performance, wherein the control algorithm module is electrically connected to the MPPT controller, the DC-DC converter, the inverter, and the battery respectively;

[0011] A monitoring and protection device is used to monitor the system status in real time and provide protection in abnormal situations, and the monitoring and protection device is electrically connected to the MPPT controller.

[0012] Furthermore, the monitoring and protection device includes a control circuit, an overload protection circuit, a short circuit protection circuit and an overheat protection circuit, and the control circuit is electrically connected to the overload protection circuit, the short circuit protection circuit and the overheat protection circuit respectively.

[0013] Further, the photovoltaic panel cell includes an equivalent circuit, which includes a PN junction Iph, a diode Io and a resistor Rp arranged in parallel, one end of the resistor Rp is connected to a resistor Rs, one end of the resistor Rs and the other end of the resistor Rp are both connected to the MPPT controller, wherein the voltage and current mathematical expression model is:

[0014] Where: Io is the reverse saturation current of the PN junction of the equivalent diode inside the photovoltaic cell, which is approximately a constant; Iph is the photocurrent of the photovoltaic cell; Ipv and Upv are the output current and output voltage of the photovoltaic cell respectively; Rp and Rs are the parallel and series resistances respectively; Q is the electron charge, Q = 1.6×10 -19 C; K is the Boltzmann constant; T is the thermodynamic temperature of the environment in which the photovoltaic cell is located; A is the curve constant of the PN junction inside the photovoltaic cell.

[0015] Furthermore, the specific process of the MPPT controller automatically adjusting the working point according to the ambient light intensity, temperature and the current working state of the photovoltaic panel battery is as follows:

[0016] A1. Measure the current output power of the photovoltaic panel battery; use the voltage sensor and current sensor to monitor the voltage and current data of the photovoltaic panel battery in real time and transmit them to the MPPT controller for processing, and multiply the measured voltage and current to obtain the total power currently generated;

[0017] A2. During the startup phase or the preset cycle, the MPPT controller will scan the entire range. The MPPT controller gradually adjusts the load and recalculates the adjusted power at each step. By comparing the power output under different load conditions, the setting that enables the panel to reach the maximum output is preliminarily determined;

[0018] A3. Once a local optimal solution is found, the MPPT controller begins to make further subtle adjustments to maintain or find a better solution;

[0019] A4. Use the perturbation and observation method to work by changing the system load by a small amount and observing the effect on the output power. If the power increases, continue to adjust the load in the same direction. If the power decreases, adjust the load in the opposite direction.

[0020] A5. Continue iterating, changing the load slightly each time, until the maximum power is found.

[0021] A6. When environmental conditions change, restart the A1-A5 process to adapt to the new environmental conditions.

[0022] Furthermore, when the perturbation and observation method is used to adjust the load in a small range, the initial conditions are first confirmed, and the output power P0 of the current photovoltaic system is measured, that is, the power at the initial working point. The power P0 at the initial working point is calculated by the voltage V0 and the current I0. The calculation formula is as follows:

[0023] P0=V0*I0;

[0024] Based on the existing working point, the load is increased or decreased slightly by adjusting the duty cycle of the DC-DC converter. Assume that the change in duty cycle is ΔD.

[0025] After adjusting the load, measure the output power P1 again, and the calculation formula is as follows:

[0026] P1=V1*I1,

[0027] Compare the new output power P1 with the initial power P0 to determine whether the power is increasing or decreasing. If P1>P0, it means the adjustment direction is correct. Continue to adjust the load in the same direction, that is, D 新 =D 旧 +ΔD;

[0028] If P1<P0, it means the adjustment direction is wrong and the load should be adjusted in the opposite direction, i.e. D 新 =D 旧 -ΔD;

[0029] Continue the above adjustment, measurement, and comparison steps, changing the load slightly each time, until the maximum power is found.

[0030] Furthermore, the inverter includes an inverter circuit for converting direct current into alternating current, a logic control circuit for controlling the operation of the entire system, and a filter circuit for filtering out interference signals, and the inverter circuit includes a boost part and an industrial frequency PWM switch part;

[0031] The boost part is mainly composed of capacitor C1, transistor Q1, coil L3, diode D2 and capacitor C2. Capacitor C1, transistor Q1 and capacitor C2 are connected in parallel, coil L3 is connected between capacitor C1 and the collector of transistor Q1, and diode D2 is connected between the collector of transistor Q1 and capacitor C2.

[0032] Further, the DC-DC converter includes a transformer T6, the input end of the transformer T6 is respectively connected to a transistor Q8 and a transistor Q9, the source end of the transistor Q8 is connected to a diode D11, the drain end of the transistor Q8 is connected to a diode D12, one end of the diode D12 is connected to the drain end of the transistor, one end of the diode D11 is connected to the source end of the transistor Q9, a diode D14 and a capacitor C15 are connected in parallel to the output end of the transformer T6, a diode D13 is connected between the connection end of the diode D14 and the transformer T6, and an inductor L14 is connected to the connection end of the diode D14 and the capacitor C15.

[0033] Furthermore, the storage battery adopts an intelligent charge and discharge management system to control the storage of excess electric energy and release it when needed. The intelligent charge and discharge management system includes a switch SB connected to the photovoltaic panel battery and comparators IC1, IC2, IC3 and IC4 arranged in parallel. One end of the switch SB is connected to the comparator IC1 through a resistor R3. The output end of the comparator IC1 is connected to a resistor R9, and one end of the resistor R9 is connected to a light-emitting diode VD3. The output end of the comparator IC2 is connected to a resistor R10, and one end of the resistor R10 is connected to a light-emitting diode VD4. The output end of the comparator IC3 is connected to a resistor R11, and one end of the resistor R11 is connected to a light-emitting diode VD5. The output end of the comparator IC4 is connected to a resistor R12, and one end of the resistor R12 is connected to a light-emitting diode VD6. A resistor R44 is connected between the comparator IC1 and the resistor R3, and a diode VD2 and a capacitor C13 are connected in parallel to the connecting end of the resistor R44 and the resistor R3. The positive terminal of C1 and the positive terminal of comparator IC2 are connected with resistor R55, the positive terminal of comparator IC2 and the positive terminal of comparator IC3 are connected with resistor R66, the positive terminal of comparator IC3 and the positive terminal of comparator IC4 are connected with resistor R77, the positive terminal of comparator IC4 is also connected with resistor R88, the negative terminal of comparator IC1 is connected with resistor R22 and resistor R12 in parallel, and one end of resistor R12 is connected to the connection end of resistor R3 and switch SB.

[0034] Furthermore, the control algorithm module includes a process of a fault detection and response mechanism, and the specific operation of the fault detection and response mechanism is as follows:

[0035] B1. Real-time monitoring of the output signal, status and behavior of photovoltaic panel batteries is carried out, and a system model is established through monitoring data. Spectrum analysis technology is used to detect whether there are any abnormalities in the system model.

[0036] B2. Use the observer to estimate the state of the system model and generate a residual signal. When there is no fault, the residual is close to zero, but when there is a fault, the residual will deviate significantly from zero.

[0037] B3, comparing the residual with a preset threshold, and triggering a fault alarm when the residual exceeds the preset threshold;

[0038] B4. After a fault is detected, the specific location and type of the fault are determined based on the model predictive control algorithm;

[0039] B5. De-noise and normalize the collected sensing monitoring data to ensure the accuracy of fault signal analysis, and then classify different types of faults;

[0040] B6. Based on the type and severity of the fault, the control algorithm independently decides to take appropriate response measures, including adjusting control parameters, switching to backup systems, and shutting down some functions to prevent the fault from spreading;

[0041] B7. For repairable faults, recalibrate the sensor or update the software operation suggestions according to the provided repair suggestions;

[0042] B8. Send alarm information to operators and provide detailed fault diagnosis reports when necessary to facilitate manual intervention and repair;

[0043] B9. Before implementing fault response measures, verify the effectiveness of the proposed measures through system models to ensure that no new unstable factors are introduced.

[0044] Based on the above-described photovoltaic power generation system performance enhancement system using an adaptive MPPT algorithm, the present invention also provides a photovoltaic power generation system performance enhancement method using an adaptive MPPT algorithm, comprising the following steps:

[0045] S1, capture solar energy through photovoltaic panels and convert it into electrical energy;

[0046] S2, using the MPPT controller to adjust the working point of the photovoltaic panel battery in real time;

[0047] S3, regulating the voltage and current of the photovoltaic panel battery through a DC-DC converter;

[0048] S4, converting direct current into alternating current through an inverter for use in a power supply grid or load;

[0049] S5. Store or release electrical energy through batteries when needed;

[0050] S6. Implement the adaptive MPPT algorithm and optimize system performance using the control algorithm module;

[0051] S7. Monitor the system status in real time and provide protection through monitoring and protection devices.

[0052] The beneficial effects of the present invention are:

[0053] 1. The present invention uses the MPPT controller to adjust the working point of the photovoltaic panel battery in real time through the mutual cooperation of the photovoltaic panel battery, the MPPT controller, the inverter, the DC-DC converter, the logic control circuit and the battery to ensure the maximum power output under the current environmental conditions, and then quickly responds to the changes in light intensity and temperature through the control algorithm module to adjust the working point to match the optimal power output. For example, in cloudy or rainy weather, it automatically adjusts according to the reduced light to continue to operate at the most efficient power point, so that a high energy utilization rate can be maintained under different climatic conditions, and real-time adjustment under different light and temperature adjustments is achieved, which significantly improves the overall power generation efficiency and system stability.

[0054] 2. The present invention can effectively identify system failures and provide corresponding response measures through the setting of the control algorithm module, ensuring that the system can quickly recover to normal operating state when a failure occurs, thereby improving the reliability and safety of the system.

[0055] 3. The present invention can achieve safe operation of equipment, extend the service life of equipment, improve system reliability and prevent safety accidents through the setting of monitoring and protection devices.

[0056] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0058] Figure 1 A system block diagram according to an embodiment of the present invention is shown;

[0059] Figure 2A flowchart according to an embodiment of the present invention is shown;

[0060] Figure 3 A circuit diagram showing an equivalent circuit according to an embodiment of the present invention is shown;

[0061] Figure 4 A circuit diagram of an inverter according to an embodiment of the present invention is shown;

[0062] Figure 5 shows a block diagram of a control circuit according to an embodiment of the present invention;

[0063] Figure 6 A circuit diagram of an intelligent charge and discharge management system according to an embodiment of the present invention is shown;

[0064] Figure 7 A circuit diagram of a DC-DC converter according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] The embodiment of the present invention provides a photovoltaic power generation system performance enhancement system based on an adaptive MPPT algorithm, such as Figure 1-7 As shown, it includes a photovoltaic panel battery for converting solar energy into electrical energy, an MPPT controller electrically connected to the photovoltaic panel battery, the MPPT controller is used to adjust the working point of the photovoltaic panel battery in real time to achieve maximum power output, and the MPPT controller adopts an adaptive algorithm to automatically adjust the working point according to the ambient light intensity, temperature and the current working state of the photovoltaic panel battery; an inverter for converting direct current into alternating current for power grid or load, a DC-DC converter connected between the MPPT controller and the inverter, the DC-DC converter is used to adjust voltage and current; a battery connected in parallel with the inverter, the battery is used to store excess electrical energy and release it when needed; a control algorithm module for implementing an adaptive MPPT algorithm and optimizing system performance, the control algorithm module is electrically connected to the MPPT controller, the DC-DC converter, the inverter and the battery respectively; a monitoring and protection device for real-time monitoring of the system status and providing protection under abnormal conditions, the monitoring and protection device is electrically connected to the MPPT controller.

[0067] The MPPT controller adjusts the working point of the photovoltaic panel cells in real time to ensure the maximum power output under the current environmental conditions. Then, the control algorithm module quickly responds to changes in light intensity and temperature and adjusts the working point to match the optimal power output. For example, in cloudy or rainy weather, it automatically adjusts according to the reduced light to continue operating at the most efficient power point, thereby maintaining a high energy utilization rate under different climatic conditions, achieving real-time adjustment under different light and temperature conditions, and significantly improving the overall power generation efficiency and system stability.

[0068] The photovoltaic panel battery is a photovoltaic panel battery array formed by connecting multiple photovoltaic panel battery cells containing silicon semiconductor PN junctions in series or in parallel. When sunlight shines on the semiconductor PN junction, new hole-electron pairs are formed. Under the action of the built-in electric field of the PN junction, holes flow from the N region to the P region, and electrons flow from the P region to the N region. After the circuit is connected, a current is formed. After photons are absorbed by the semiconductor, electron-hole pairs are generated. Before the electron-hole pairs are recombined, they are separated by the electric field of the space charge region and flow to the N region and the P region respectively, forming a photo-generated voltage, which is used to obtain a greater output power through the photovoltaic panel battery array.

[0069] The photovoltaic panel cell includes an equivalent circuit, such as Figure 3 As shown, the equivalent circuit includes a PN junction Iph, a diode Io and a resistor Rp which are arranged in parallel, one end of the resistor Rp is connected to a resistor Rs, one end of the resistor Rs and the other end of the resistor Rp are both connected to the MPPT controller, wherein the voltage and current mathematical expression model is:

[0070] Where: Io is the reverse saturation current of the PN junction of the equivalent diode inside the photovoltaic cell, which is approximately a constant; Iph is the photocurrent of the photovoltaic cell; Ipv and Upv are the output current and output voltage of the photovoltaic cell respectively; Rp and Rs are the parallel and series resistances respectively; Q is the electron charge, Q = 1.6×10 -19 C; K is the Boltzmann constant; T is the thermodynamic temperature of the environment in which the photovoltaic cell is located; A is the curve constant of the PN junction inside the photovoltaic cell.

[0071] The specific process of the MPPT controller automatically adjusting the working point according to the ambient light intensity, temperature and the current working state of the photovoltaic panel battery is as follows:

[0072] A1. Measure the current output power of the photovoltaic panel battery; use the voltage sensor and current sensor to monitor the voltage and current data of the photovoltaic panel battery in real time and transmit them to the MPPT controller for processing, and multiply the measured voltage and current to obtain the total power currently generated;

[0073] A2. During the startup phase or the preset cycle, the MPPT controller will scan the entire range. The MPPT controller gradually adjusts the load and recalculates the adjusted power at each step. By comparing the power output under different load conditions, the setting that enables the panel to reach the maximum output is preliminarily determined;

[0074] A3. Once a local optimal solution is found, the MPPT controller begins to make further subtle adjustments to maintain or find a better solution;

[0075] A4. The perturbation and observation method works by changing the system load by small amounts and observing the effect on the output power. If the power increases, continue to adjust the load in the same direction. If the power decreases, adjust the load in the opposite direction.

[0076] A5. Continue iterating, changing the load slightly each time, until the maximum power is found.

[0077] A6. When environmental conditions change, restart the A1-A5 process to adapt to the new environmental conditions.

[0078] The perturbation and observation method determines the maximum power point by continuously adjusting the load in small increments and observing the changes in output power. This method is simple and easy to use, applicable to various photovoltaic systems, and can effectively improve energy utilization.

[0079] When the perturbation and observation method is used to adjust the load in a small range, the initial conditions are first confirmed and the output power P0 of the current photovoltaic system is measured, that is, the power at the initial working point. The power P0 at the initial working point is calculated by the voltage V0 and the current I0, and the calculation formula is as follows:

[0080] P0=V0*I0;

[0081] Based on the existing working point, the load is increased or decreased slightly by adjusting the duty cycle of the DC-DC converter. Assume that the change in duty cycle is ΔD.

[0082] After adjusting the load, measure the output power P1 again, and the calculation formula is as follows:

[0083] P1=V1*I1,

[0084] Compare the new output power P1 with the initial power P0 to determine whether the power is increasing or decreasing. If P1>P0, it means the adjustment direction is correct. Continue to adjust the load in the same direction, that is, D 新 =D 旧 +ΔD;

[0085] If P1<P0, it means the adjustment direction is wrong and the load should be adjusted in the opposite direction, i.e. D 新 =D 旧 -ΔD;

[0086] Continue to perform the above adjustment, measurement and comparison steps, each time changing the load slightly until the maximum power is found. When the power change is less than a preset threshold, it can be considered that the maximum power point has been reached. Due to the continuous changes in environmental conditions, the system needs to continuously perform the above steps to ensure that the photovoltaic panel cells always operate near the maximum power point.

[0087] The inverter includes an inverter circuit for converting direct current into alternating current, a logic control circuit for controlling the operation of the entire system, and a filter circuit for filtering out interference signals. The inverter circuit includes a boost part and an industrial frequency PWM switch part. Through the coordinated work of the industrial frequency PWM switch part and the boost part, it can adapt to a wide input DC voltage range, which is conducive to matching with photovoltaic panel batteries. Although the output voltage of the photovoltaic panel battery changes due to factors such as weather, the boost part can ensure that the input voltage of the inverter part is relatively stable.

[0088] The boost part is mainly composed of capacitor C1, transistor Q1, coil L3, diode D2 and capacitor C2. Capacitor C1, transistor Q1 and capacitor C2 are connected in parallel, coil L3 is connected between capacitor C1 and the collector of transistor Q1, and diode D2 is connected between the collector of transistor Q1 and capacitor C2.

[0089] The industrial frequency PWM switch part is mainly composed of a bridge arm circuit composed of a switch tube Q2, a switch tube Q3, a switch tube Q4 and a switch tube Q5. The filter circuit includes a coil L1 and a coil L2 connected to the bridge arm circuit. One end of the coil L1 and one end of the coil L2 are both connected to the power grid. One end of the coil L1 is connected in parallel with a capacitor C5 and is connected in series with a capacitor C3 and a capacitor C4. One end of the capacitor C4 and one end of the capacitor C5 are both connected to an end of the coil L3 away from the diode D2. During the charging process, the switch is closed, the input voltage flows through the inductor, and the current on the inductor increases linearly at a certain ratio, thereby storing some energy. During the discharge process, the switch is disconnected. Due to the current retention characteristics of the inductor, the current flowing through the inductor will not immediately become 0, but gradually decrease. The inductor begins to charge the capacitor, causing the voltage across the capacitor to increase, thereby achieving a boost.

[0090] When the logic control circuit performs logic control, a voltage Hall sensor is used to sample the output voltage, and the sampling period is 20kHz, that is, 20,000 samples are taken per second; the output signal of the voltage Hall sensor is sent to the DSP analog-to-digital conversion unit through the conditioning circuit, and the conversion result is temporarily stored in the DSP, thereby obtaining feedback information of the output voltage; then the sampled feedback information is compared with the corresponding data of the given sine table to obtain a deviation signal; then the deviation signal and the given signal are calculated according to a certain control algorithm to obtain a pulse width control amount, wherein the control algorithm adopts a method of repetitive control plus PID control, wherein the repetitive control is to ensure the steady-state performance of the output waveform, and the PID control is to ensure the dynamic performance of the output waveform.

[0091] The duty cycle of the SPWM wave at the current moment can be calculated from the pulse width control quantity, so that the duty cycle of the output waveform changes according to the sinusoidal law, and a high-frequency SPWM wave is obtained. Considering that the upper and lower bridge arms of the full-bridge inverter cannot be directly connected, the corresponding dead zone must be added to the DSP's PWM output. The addition of the dead zone is extremely convenient. You only need to set the dead zone register inside the DSP during software programming, and the dead zone will be automatically added to the existing PWM wave. The dead zone time can be adjusted by setting different values ​​for the register. The high-frequency SPWM wave is passed to the drive circuit, and the drive pulse generated by the drive circuit controls the on / off of the power switch tube, thereby generating an SPWM wave that changes according to the sinusoidal law, and then filtered by LC to remove the high-frequency component to obtain a sinusoidal output voltage.

[0092] The electricity generated by the photovoltaic panel battery is used to power the load through the inverter, which mainly controls the output power. In addition to power control, the inverter control circuit also includes tracking the optimal working point control of the photovoltaic panel battery, power factor compensation and boost control. The control circuit block diagram is shown in the figure. Figure 5 shown.

[0093] like Figure 7 As shown, the DC-DC converter includes a transformer T6, the input end of the transformer T6 is respectively connected to a transistor Q8 and a transistor Q9, the source end of the transistor Q8 is connected to a diode D11, the drain end of the transistor Q8 is connected to a diode D12, one end of the diode D12 is connected to the drain end of the transistor, one end of the diode D11 is connected to the source end of the transistor Q9, a diode D14 and a capacitor C15 are connected in parallel at the output end of the transformer T6, a diode D13 is connected between the diode D14 and the connection end of the transformer T6, and an inductor L14 is connected to the connection end of the diode D14 and the capacitor C15;

[0094] The storage battery adopts an intelligent charge and discharge management system to control the storage of excess electric energy and release it when needed. The intelligent charge and discharge management system includes a switch SB connected to the photovoltaic panel battery and comparators IC1, IC2, IC3 and IC4 arranged in parallel. One end of the switch SB is connected to the comparator IC1 through a resistor R3. The output end of the comparator IC1 is connected to a resistor R9, and one end of the resistor R9 is connected to a light-emitting diode VD3. The output end of the comparator IC2 is connected to a resistor R10, and one end of the resistor R10 is connected to a light-emitting diode VD4. The output end of the comparator IC3 is connected to a resistor R11, and one end of the resistor R11 is connected to a light-emitting diode VD5. The output end of the comparator IC4 is connected to a resistor R12, and one end of the resistor R12 is connected to a light-emitting diode VD6. A resistor R44 is connected between the comparator IC1 and the resistor R3. The connecting end of the resistor R44 and the resistor R3 is connected in parallel with a diode VD2 and a capacitor C13. The positive terminal of C1 and the positive terminal of comparator IC2 are connected with resistor R55, the positive terminal of comparator IC2 and the positive terminal of comparator IC3 are connected with resistor R66, the positive terminal of comparator IC3 and the positive terminal of comparator IC4 are connected with resistor R77, the positive terminal of comparator IC4 is also connected with resistor R88, the negative terminal of comparator IC1 is connected with resistor R22 and resistor R12 in parallel, and one end of resistor R12 is connected to the connection end of resistor R3 and switch SB.

[0095] The control algorithm module includes the process of fault detection and response mechanism. The specific operation of the fault detection and response mechanism is as follows:

[0096] B1. By monitoring the output signal, status and behavior of the photovoltaic panel battery in real time, the system model is established through the monitoring data, and the spectrum analysis technology is used to detect whether there is an abnormality in the system model. The spectrum analysis technology includes signal acquisition, spectrum conversion, spectrum analysis, abnormality detection, alarm response, data analysis and optimization and update. These steps together ensure that the system can be detected and processed in time when an abnormality occurs, thereby ensuring the stable operation and safety performance of the system. The spectrum analysis technology is an existing technology and will not be described in detail here;

[0097] B2. Use the observer to estimate the state of the system model and generate a residual signal. When there is no fault, the residual is close to zero, but when there is a fault, the residual will deviate significantly from zero.

[0098] B3, comparing the residual with a preset threshold, and triggering a fault alarm when the residual exceeds the preset threshold;

[0099] B4. After a fault is detected, the specific location and type of the fault are determined based on the model predictive control algorithm;

[0100] B5. De-noise and normalize the collected sensing monitoring data to ensure the accuracy of fault signal analysis, and then classify different types of faults;

[0101] B6. Based on the type and severity of the fault, the control algorithm independently decides to take appropriate response measures, including adjusting control parameters, switching to backup systems, and shutting down some functions to prevent the fault from spreading;

[0102] B7. For repairable faults, recalibrate the sensor or update the software operation suggestions according to the provided repair suggestions;

[0103] B8. Send alarm information to operators and provide detailed fault diagnosis reports when necessary to facilitate manual intervention and repair;

[0104] B9. Before implementing fault response measures, verify the effectiveness of the proposed measures through system models to ensure that no new unstable factors are introduced;

[0105] The control algorithm module can effectively identify system faults and provide corresponding response measures to ensure that the system can quickly recover to normal operation when a fault occurs, thereby improving the reliability and safety of the system.

[0106] The monitoring and protection device includes a control circuit, an overload protection circuit, a short-circuit protection circuit and an overheating protection circuit. The control circuit is electrically connected to the overload protection circuit, the short-circuit protection circuit and the overheating protection circuit respectively. The overload protection adopts a thermal relay. When the current exceeds the set value, the heating element of the thermal relay will trigger the disconnection circuit; the short-circuit protection is to connect a fuse or a low-voltage circuit breaker in series in the line to cut off the power supply in a very short time after the short-circuit fault occurs; the overheating protection circuit monitors the equipment temperature and automatically cuts off the power supply when it exceeds the set threshold, thereby protecting the safe operation of the equipment; the control circuit is used to control the on and off of the overload protection circuit, the short-circuit protection circuit and the overheating protection circuit. Through the coordinated cooperation of the control circuit, the overload protection circuit, the short-circuit protection circuit and the overheating protection circuit, the safe operation of the equipment can be achieved, the service life of the equipment can be extended, the system reliability can be improved, and the effect of preventing safety accidents can be achieved.

[0107] Based on the above-described photovoltaic power generation system performance enhancement system using an adaptive MPPT algorithm, the present invention also provides a photovoltaic power generation system performance enhancement method using an adaptive MPPT algorithm, comprising the following steps:

[0108] S1, capture solar energy through photovoltaic panels and convert it into electrical energy;

[0109] S2, using the MPPT controller to adjust the working point of the photovoltaic panel battery in real time;

[0110] S3, regulating the voltage and current of the photovoltaic panel battery through a DC-DC converter;

[0111] S4, converting direct current into alternating current through an inverter for use in a power supply grid or load;

[0112] S5. Store or release electrical energy through batteries when needed;

[0113] S6. Implement the adaptive MPPT algorithm and optimize system performance using the control algorithm module;

[0114] S7. Monitor the system status in real time and provide protection through monitoring and protection devices.

[0115] The above steps can improve energy conversion efficiency, optimize system performance, enhance system stability and reliability, improve power quality, increase energy utilization, reduce maintenance costs, and improve user satisfaction.

[0116] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photovoltaic power generation system performance enhancement system based on an adaptive MPPT algorithm, characterized in that: These include photovoltaic panel cells used to convert solar energy into electricity; An MPPT controller electrically connected to the photovoltaic panel battery, the MPPT controller is used to adjust the working point of the photovoltaic panel battery in real time to achieve maximum power output, and the MPPT controller uses an adaptive algorithm to automatically adjust the working point according to the ambient light intensity, temperature and the current working state of the photovoltaic panel battery; Inverter used to convert DC power into AC power for power grid or load; A DC-DC converter connected between the MPPT controller and the inverter, the DC-DC converter being used to regulate voltage and current; A battery connected in parallel with the inverter, the battery is used to store excess electrical energy and release it when needed; A control algorithm module for implementing an adaptive MPPT algorithm and optimizing system performance, wherein the control algorithm module is electrically connected to the MPPT controller, the DC-DC converter, the inverter, and the battery respectively; A monitoring and protection device is used to monitor the system status in real time and provide protection in abnormal situations, and the monitoring and protection device is electrically connected to the MPPT controller.

2. The photovoltaic power generation system performance enhancement system of the adaptive MPPT algorithm according to claim 1 is characterized by: The monitoring and protection device comprises a control circuit, an overload protection circuit, a short circuit protection circuit and an overheat protection circuit, and the control circuit is electrically connected to the overload protection circuit, the short circuit protection circuit and the overheat protection circuit respectively.

3. The photovoltaic power generation system performance enhancement system of the adaptive MPPT algorithm according to claim 2 is characterized by: The photovoltaic panel cell includes an equivalent circuit, which includes a PN junction Iph, a diode Io and a resistor Rp arranged in parallel, one end of the resistor Rp is connected to a resistor Rs, one end of the resistor Rs and the other end of the resistor Rp are both connected to the MPPT controller, wherein the voltage and current mathematical expression model is: Where: Io is the reverse saturation current of the PN junction of the equivalent diode inside the photovoltaic cell, which is approximately a constant; Iph is the photocurrent of the photovoltaic cell; Ipv and Upv are the output current and output voltage of the photovoltaic cell respectively; Rp and Rs are the parallel and series resistances respectively; Q is the electron charge, Q = 1.6×10 -19 C; K is the Boltzmann constant; T is the thermodynamic temperature of the environment in which the photovoltaic cell is located; A is the curve constant of the PN junction inside the photovoltaic cell.

4. The photovoltaic power generation system performance enhancement system of the adaptive MPPT algorithm according to claim 3 is characterized by: The specific process of the MPPT controller automatically adjusting the working point according to the ambient light intensity, temperature and the current working state of the photovoltaic panel battery is as follows: A1. Measure the current output power of the photovoltaic panel battery; use the voltage sensor and current sensor to monitor the voltage and current data of the photovoltaic panel battery in real time and transmit them to the MPPT controller for processing, and multiply the measured voltage and current to obtain the total power currently generated; A2. During the startup phase or the preset cycle, the MPPT controller will scan the entire range. The MPPT controller gradually adjusts the load and recalculates the adjusted power at each step. By comparing the power output under different load conditions, the setting that enables the panel to reach the maximum output is preliminarily determined; A3. Once a local optimal solution is found, the MPPT controller begins to make further subtle adjustments to maintain or find a better solution; A4. Use the perturbation and observation method to work by changing the system load by a small amount and observing the effect on the output power. If the power increases, continue to adjust the load in the same direction. If the power decreases, adjust the load in the opposite direction. A5. Continue iterating, changing the load slightly each time, until the maximum power is found. A6. When environmental conditions change, restart the A1-A5 process to adapt to the new environmental conditions.

5. The photovoltaic power generation system performance enhancement system of the adaptive MPPT algorithm according to claim 4 is characterized by: When the perturbation and observation method is used to adjust the load in a small range, the initial conditions are first confirmed and the output power P0 of the current photovoltaic system is measured, that is, the power at the initial working point. The power P0 at the initial working point is calculated by the voltage V0 and the current I0. The calculation formula is as follows: P0=V0*I0; Based on the existing working point, the load is increased or decreased slightly by adjusting the duty cycle of the DC-DC converter. Assume that the change in duty cycle is ΔD. After adjusting the load, measure the output power P1 again, and the calculation formula is as follows: P1=V1*I1, Compare the new output power P1 with the initial power P0 to determine whether the power is increasing or decreasing. If P1>P0, it means the adjustment direction is correct. Continue to adjust the load in the same direction, that is, D 新 =D 旧 +ΔD; If P1<P0, it means the adjustment direction is wrong and the load should be adjusted in the opposite direction, i.e. D 新 =D 旧 -ΔD; Continue the above adjustment, measurement, and comparison steps, changing the load slightly each time, until the maximum power is found.

6. The photovoltaic power generation system performance enhancement system of the adaptive MPPT algorithm according to claim 5 is characterized by: The inverter includes an inverter circuit for converting direct current into alternating current, a logic control circuit for controlling the operation of the entire system, and a filter circuit for filtering out interference signals. The inverter circuit includes a boost part and an industrial frequency PWM switch part. The boost part is mainly composed of capacitor C1, transistor Q1, coil L3, diode D2 and capacitor C2. Capacitor C1, transistor Q1 and capacitor C2 are connected in parallel, coil L3 is connected between capacitor C1 and the collector of transistor Q1, and diode D2 is connected between the collector of transistor Q1 and capacitor C2.

7. The photovoltaic power generation system performance enhancement system of the adaptive MPPT algorithm according to claim 6 is characterized by: The DC-DC converter includes a transformer T6, the input end of the transformer T6 is respectively connected to a transistor Q8 and a transistor Q9, the source end of the transistor Q8 is connected to a diode D11, the drain end of the transistor Q8 is connected to a diode D12, one end of the diode D12 is connected to the drain end of the transistor, one end of the diode D11 is connected to the source end of the transistor Q9, a diode D14 and a capacitor C15 are connected in parallel to the output end of the transformer T6, a diode D13 is connected between the diode D14 and the connection end of the transformer T6, and an inductor L14 is connected to the connection end of the diode D14 and the capacitor C15.

8. The photovoltaic power generation system performance enhancement system of the adaptive MPPT algorithm according to claim 7 is characterized by: The battery adopts an intelligent charge and discharge management system to control the storage of excess electric energy and release it when needed. The intelligent charge and discharge management system includes a switch SB connected to the photovoltaic panel battery and comparators IC1, IC2, IC3 and IC4 arranged in parallel. One end of the switch SB is connected to the comparator IC1 through a resistor R3. The output end of the comparator IC1 is connected to a resistor R9, and one end of the resistor R9 is connected to a light-emitting diode VD3. The output end of the comparator IC2 is connected to a resistor R10, and one end of the resistor R10 is connected to a light-emitting diode VD4. The output end of the comparator IC3 is connected to a resistor R11, and one end of the resistor R11 is connected to a light-emitting diode VD5. 4 is connected to a resistor R12, one end of the resistor R12 is connected to a light emitting diode VD6, a resistor R44 is connected between the comparator IC1 and the resistor R3, a diode VD2 and a capacitor C13 are connected in parallel to the connecting end of the resistor R44 and the resistor R3, a resistor R55 is connected between the positive end of the comparator IC1 and the positive end of the comparator IC2, a resistor R66 is connected between the positive end of the comparator IC2 and the positive end of the comparator IC3, a resistor R77 is connected between the positive end of the comparator IC3 and the positive end of the comparator IC4, a resistor R88 is also connected to the positive end of the comparator IC4, a resistor R22 and a resistor R12 are connected in parallel to the negative end of the comparator IC1, and one end of the resistor R12 is connected to the connecting end of the resistor R3 and the switch SB.

9. The photovoltaic power generation system performance enhancement system of the adaptive MPPT algorithm according to claim 8, characterized in that: The control algorithm module includes the process of fault detection and response mechanism. The specific operation of the fault detection and response mechanism is as follows: B1. Real-time monitoring of the output signal, status and behavior of photovoltaic panel batteries is carried out, and a system model is established through monitoring data. Spectrum analysis technology is used to detect whether there are any abnormalities in the system model. B2. Use the observer to estimate the state of the system model and generate a residual signal. When there is no fault, the residual is close to zero, but when there is a fault, the residual will deviate significantly from zero. B3, comparing the residual with a preset threshold, and triggering a fault alarm when the residual exceeds the preset threshold; B4. After a fault is detected, the specific location and type of the fault are determined based on the model predictive control algorithm; B5. De-noise and normalize the collected sensing monitoring data to ensure the accuracy of fault signal analysis, and then classify different types of faults; B6. Based on the type and severity of the fault, the control algorithm independently decides to take appropriate response measures, including adjusting control parameters, switching to backup systems, and shutting down some functions to prevent the fault from spreading; B7. For repairable faults, recalibrate the sensor or update the software operation suggestions according to the provided repair suggestions; B8. Send alarm information to operators and provide detailed fault diagnosis reports when necessary to facilitate manual intervention and repair; B9. Before implementing fault response measures, verify the effectiveness of the proposed measures through system models to ensure that no new unstable factors are introduced.

10. A method for enhancing the performance of a photovoltaic power generation system using an adaptive MPPT algorithm, a system for enhancing the performance of a photovoltaic power generation system using an adaptive MPPT algorithm according to any one of claims 1 to 9, characterized in that: The steps include: S1, capture solar energy through photovoltaic panels and convert it into electrical energy; S2, using the MPPT controller to adjust the working point of the photovoltaic panel battery in real time; S3, regulating the voltage and current of the photovoltaic panel battery through a DC-DC converter; S4, converting direct current into alternating current through an inverter for use in a power supply grid or load; S5. Store or release electrical energy through batteries when needed; S6. Implement the adaptive MPPT algorithm and optimize system performance using the control algorithm module; S7. Monitor the system status in real time and provide protection through monitoring and protection devices.

Images