Photovoltaic-thermoelectric coupling system maximum power point tracking control method and system

Abstract

The invention discloses a photovoltaic-thermoelectric coupling system maximum power point tracking control method and system. The method comprises the following steps: acquiring environmental irradiance, output voltage and output current in real time; determining output power according to the output voltage and the output current; determining an output voltage range according to the environmental irradiance; when the output voltage is not within the output voltage range, adjusting the output voltage until the adjusted output voltage is within the output voltage range; determining the output voltage enabling the system output power to be maximum in the output voltage range as the optimal output voltage; and controlling the system according to the optimal output voltage, so that the system is stabilized at the maximum power point. And high-precision and high-efficiency tracking of the maximum power point of the photovoltaic-thermoelectric coupling system is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of solar power generation, and particularly to a maximum power point tracking control method and system for a photovoltaic-thermoelectric coupling system. Background Technique

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] Photovoltaic cells directly convert the ultraviolet and visible regions of the solar spectrum into electrical energy, and thermoelectric cells generate electrical energy using the energy in the infrared region. A photovoltaic-thermoelectric coupling system is composed of photovoltaic cells and thermoelectric cells. The system uses the waste heat of photovoltaic cells through thermoelectric cells to generate electrical energy, which is an effective method to improve the system output power and solar energy conversion efficiency.

[0004] Photovoltaic power generation converts part of the irradiance into electrical energy, and the rest is lost in the form of heat. The photovoltaic-thermoelectric coupling system converts waste heat into electrical energy, and has a higher correlation with irradiance compared with photovoltaic power generation. The maximum power of solar power generation can be known theoretically according to the irradiance and battery parameters.

[0005] When the current photovoltaic-thermoelectric coupling system performs maximum power point tracking control according to irradiance, first determine the voltage reference value according to the irradiance, and then gradually adjust the output voltage of the system to the voltage reference value at a fixed step size to stabilize the system at the maximum power point. However, since this method adjusts the output voltage with a fixed step size, it cannot ensure that the output maximum power is the maximum power that the system can theoretically output, that is, the maximum power point tracking accuracy of the system is limited. In addition, when adjusting the output voltage in the way of a fixed step size, when the error between the output voltage and the voltage reference value is large, the voltage adjustment efficiency is low. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a maximum power point tracking control method and system for a photovoltaic-thermoelectric coupling system, which adopts a variable step size strategy to adjust the output voltage, and improves the tracking efficiency on the basis of ensuring the maximum power point tracking accuracy.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In the first aspect, a maximum power point tracking control method for a photovoltaic-thermoelectric coupling system is proposed, including:

[0009] Obtain the ambient irradiance, output voltage and output current in real time;

[0010] Determine the output power according to the output voltage and output current;

[0011] Determine the output voltage range according to the ambient irradiance;

[0012] When the output voltage is not within the output voltage range, adjust the output voltage so that the adjusted output voltage is within the output voltage range;

[0013] Determine the output voltage that maximizes the system output power from within the output voltage range as the optimal output voltage;

[0014] Control the system according to the optimal output voltage so that the system is stabilized at the maximum power point.

[0015] Furthermore, determine the theoretical reference value of the output voltage that maximizes the system output power according to the environmental irradiance; increase and decrease the theoretical reference value of the output voltage by a set ratio to obtain the output voltage range.

[0016] Furthermore, with the goal of maximizing the output power, use the cuckoo algorithm to search within the output voltage range to determine the optimal output voltage.

[0017] Furthermore, determine the duty cycle corresponding to the optimal output voltage as the optimal duty cycle;

[0018] Control the system according to the optimal duty cycle so that the system is stabilized at the maximum power point.

[0019] Furthermore, the cuckoo algorithm determines the optimal output voltage by searching for the duty cycle, and determines the optimal duty cycle while determining the optimal output voltage.

[0020] Furthermore, when the output voltage is within the output voltage range, directly determine the output voltage that maximizes the output power from within the output voltage range as the optimal output voltage.

[0021] In a second aspect, a maximum power point tracking control system for a photovoltaic-thermoelectric coupling system is proposed, including:

[0022] A data acquisition unit for real-time acquisition of environmental irradiance, output voltage, and output current;

[0023] An output power calculation unit for determining the output power according to the output voltage and output current;

[0024] An output voltage range determination unit for determining the output voltage range according to the environmental irradiance;

[0025] An output voltage adjustment unit for adjusting the output voltage so that the adjusted output voltage is within the output voltage range when the output voltage is not within the output voltage range;

[0026] The maximum power point maintaining unit is used to determine, from within the output voltage range, the output voltage that maximizes the system output power as the optimal output voltage, and to control the system according to the optimal output voltage so that the system is stabilized at the maximum power point.

[0027] In a third aspect, a computer device is provided, which includes:

[0028] A processor adapted to execute a computer program;

[0029] A computer-readable storage medium storing a computer program, which, when executed by the processor, implements a maximum power point tracking control method for a photovoltaic-thermoelectric coupled system proposed in the first aspect.

[0030] In a fourth aspect, a computer-readable storage medium is provided, which stores a computer program adapted to be loaded and executed by a processor to implement a maximum power point tracking control method for a photovoltaic-thermoelectric coupled system proposed in the first aspect.

[0031] In a fifth aspect, a computer program product is provided, which includes a computer program that, when executed by a processor, implements a maximum power point tracking control method for a photovoltaic-thermoelectric coupled system proposed in the first aspect.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] For a maximum power point tracking control method and system for a photovoltaic-thermoelectric coupled system proposed by the present invention, when performing maximum power point tracking control, first, according to the environmental irradiance, the output voltage range is determined, and the output voltage outside the output voltage range is adjusted so that the adjusted output voltage is within the output voltage range; then, the output voltage that maximizes the output power is determined from within the output voltage range as the optimal output voltage; and the system is controlled according to the optimal output voltage so that the system is stabilized at the maximum power point; on the basis of ensuring the maximum power point tracking accuracy, the tracking efficiency is improved.

[0034] Advantages of additional aspects of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation to this application.

[0036] Figure 1Flowchart of the irradiance-involved MPPT main program disclosed in the embodiment;

[0037] Figure 2 Modeling of the MPPT drive circuit disclosed in the embodiment;

[0038] Figure 3 Schematic diagram of the sampling circuit disclosed in the embodiment;

[0039] Figure 4 Flowchart of the cuckoo algorithm disclosed in the embodiment. Detailed implementation manners

[0040] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0041] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0042] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0043] In the case of no conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0044] Embodiment 1

[0045] Currently, solar tracking technology and maximum power point tracking technology are two independent technologies, and the research purpose of both technologies is to improve the power generation of solar power generation systems. Feedback the irradiance data in the solar tracking process, and introduce the irradiance parameter into the maximum power point tracking (MPPT) control. By establishing a connection between the irradiance data and solar hybrid tracking, integrated control of power tracking can be achieved.

[0046] In this embodiment, in order to improve the efficiency and accuracy of the maximum power point tracking control of the photovoltaic-thermoelectric coupling system, the irradiance of the environment where the photovoltaic-thermoelectric coupling system is located, the output voltage and output current of the system are sampled in real time. The output voltage range is determined through the environmental irradiance, and the output voltage is adjusted to within the output voltage range; then, the output voltage is further adjusted so that the output power of the system reaches the maximum, realizing the tracking control of the maximum power point; the variable step size strategy is adopted to adjust the output voltage, and on the basis of ensuring the maximum power point tracking accuracy, the tracking efficiency is improved.

[0047] The present embodiment discloses a maximum power point tracking control method for a photovoltaic-thermoelectric coupling system. By integrating irradiance parameters, a new integrated control mode of power tracking for a photovoltaic-thermoelectric coupling system is constructed that takes into account both irradiance reception and maximum power point tracking. The photovoltaic-thermoelectric coupling system is controlled within the irradiance measurement range to achieve MPPT, so as to improve the system operation speed. When performing dynamic MPPT control, the output power of the photovoltaic-thermoelectric coupling system and the irradiance of the environment are detected, the maximum output power is determined according to the environmental irradiance, and the output voltage range is delimited according to the maximum output power. At the same time, the output voltage of the photovoltaic-thermoelectric coupling system is adjusted according to the change of the output power. While completing the dual-axis tracking of power irradiance, the surface irradiance of the system is collected, and the irradiance parameters are sent to the MPPT link for dynamic MPPT. First, the maximum output power is determined according to the current irradiance, and the output voltage range is determined according to the maximum output power. The output voltage is adjusted in detail according to the output voltage range. The cuckoo algorithm is used to determine the maximum output power of the system, and the duty cycle corresponding to the maximum output power is determined to adjust the working voltage. On the basis of ensuring the accuracy of the maximum power point tracking control, the efficiency of the tracking control is improved.

[0048] This embodiment discloses a maximum power point tracking control method for a photovoltaic-thermoelectric coupling system. Figures 1-4 As shown, including:

[0049] Obtain environmental irradiance, output voltage and output current in real time;

[0050] Determine the output power according to the output voltage and output current;

[0051] Determine the output voltage range according to the ambient irradiance;

[0052] When the output voltage is not within the output voltage range, the output voltage is adjusted until the adjusted output voltage is within the output voltage range;

[0053] Determine the output voltage that maximizes the system output power from the output voltage range as the optimal output voltage;

[0054] According to the optimal output voltage, the system is controlled to stabilize the system at the maximum power point.

[0055] Furthermore, when the output voltage is within the output voltage range, the output voltage that maximizes the output power is directly determined from within the output voltage range as the optimal output voltage.

[0056] Among them, according to the environmental irradiance, the output voltage theoretical reference value that maximizes the system output power is determined; the output voltage theoretical reference value is increased and decreased by a set ratio to obtain the output voltage range.

[0057] Furthermore, aiming at the maximum output power, the cuckoo algorithm is used to search within the output voltage range to determine the optimal output voltage.

[0058] Furthermore, determine the duty cycle corresponding to the optimal output voltage as the optimal duty cycle;

[0059] Control the system according to the optimal duty cycle to make the system stable at the maximum power point.

[0060] Furthermore, the cuckoo algorithm determines the optimal output voltage by searching the duty cycle, and determines the optimal duty cycle while determining the optimal output voltage.

[0061] Specifically, in this embodiment, first, an initial output voltage is set according to the initial characteristics of the photovoltaic-thermoelectric coupling system. The current environmental irradiance is read by an irradiance sensor. The output voltage and output current of the photovoltaic-thermoelectric coupling system are read in real time. The current output power is calculated according to the output voltage and output current.

[0062] Secondly, determine the maximum output power of the system in combination with the environmental irradiance, and delimit the output voltage range according to the maximum output power. If the current output voltage is not within the delimited output voltage range, adjust the output voltage until the current output voltage enters the delimited output voltage range.

[0063] Thirdly, aiming at the maximum output power of the system, the cuckoo algorithm is used to search within the output voltage range to determine the optimal output voltage.

[0064] After that, monitor the change of the environmental irradiance in real time. When the environmental irradiance changes, readjust the working voltage according to the new environmental irradiance and perform the maximum output power point tracking again.

[0065] Finally, continuously monitor the output voltage, current and power of the photovoltaic-thermoelectric coupling system, as well as the environmental irradiance. Adjust the working state according to the real-time data to ensure that the system operates stably near the maximum power point.

[0066] In this embodiment, the MPPT control system performs maximum power point tracking control on the photovoltaic-thermoelectric coupling system. When starting the MPPT control system, it first initializes various parts of the system, including the system clock, general port configuration, ADC configuration, etc. The sampling circuit collects the output voltage and output current of the photovoltaic-thermoelectric coupling system and sends them to the main control chip of the MPPT control system for control. The duty cycle is calculated through an algorithm to determine whether the output voltage reaches the output voltage range, and the duty cycle is continuously changed for optimization. The portable gas detector JXBS-3001-ZFS measures the solar irradiance, and the detector transmits the obtained environmental irradiance to the MPPT control system through the USB to RS485 module, enabling the irradiance to participate in the maximum power point tracking control of the photovoltaic-thermoelectric coupling system. The MPPT control system outputs an appropriate pulse width modulation signal (PWM signal) to make the photovoltaic-thermoelectric coupling system output the maximum power and achieve the MPPT function. In the drive circuit, the output PWM signal is amplified to control the working state of the MOSFET transistor (MOS transistor). As Figure 1 shown, the sampling circuit also collects the battery voltage to control the charging and discharging of the battery; when the battery voltage is less than the set value, the battery is charged, and during the charging process of the battery, the battery current is monitored, and when the battery current is greater than the rated current value, the charging is stopped.

[0067] The MPPT control system drives the MOSFET transistor through the pulse width modulation signal analyzed and processed by the MPPT drive circuit. The drive circuit plays an isolation role during the operation of the circuit to prevent the main circuit signal from affecting the control circuit. If the PWM signal output by the MPPT drive circuit is too small, it needs to be amplified by the amplifier circuit to control the turn-off of the MOS transistor. The MPPT drive circuit is as Figure 2 shown.

[0068] The microcontroller collects the charging voltage and current, and outputs the PWM1 signal through the MPPT algorithm to control the charging voltage. The working voltage and working current of the load are collected, and the PWM2 signal is output through the MPPT algorithm to adjust the working voltage of the load. The input of the system is connected through the capacitor filter network of C1 and C 20 . The PWM1 signal controls Q3 for voltage regulation through the series current limiting resistor R 34 , and Q3 controls Q1 to further control the charging voltage of the battery. L1 is a high-frequency choke coil, and C3 and C 50 are filter networks. The voltage is collected by measuring the voltage across both sides of R8. The voltage acquisition circuit is mainly composed of an inverting proportional operational amplifier, and R3, R 10 and R 11 constitute proportional amplification. The voltage output by the network passes through R 32The current-limiting resistor is connected to the main control unit. Q6 is an NPN transistor, and its on-off is controlled by adjusting the PWM2 signal. Q6 controls the conduction and disconnection of Q4 to further control the magnitude of the working voltage. L2 is a high-frequency inductor, and C9 and C 10 form a filter network. Measure the voltage across R 13 , and connect a reverse proportional operational amplifier in series with R 33 The current-limiting resistor is connected to the main control network to regulate the PWM2 signal.

[0069] The sampling circuit includes a voltage sampling circuit and a current sampling circuit. The voltage sampling circuit and the current sampling circuit are as Figure 3 shown. R9, R 10 and R 11 are the proportionality coefficients of the amplifier. Voltage acquisition is performed by voltage division using R3 and R6, and the voltage division ratio is 1 / 11. The current sampling circuit is as shown in the figure, where R8 is the voltage division resistor and uses a reverse proportional amplification. The output of the operational amplifier is connected in series with a current-limiting resistor R 32 to prevent excessive current from damaging the control unit.

[0070] In this embodiment, the irradiance acquisition is combined with the MPPT control technology of the photovoltaic-thermoelectric coupling system, which can take into account the advantages of both tracking methods. First, place JXBS-3001-ZFS at the horizontal position of the photovoltaic-thermoelectric coupling system to measure the irradiance. This detector transmits data to the MPPT control system terminal through a USB to RS485 module. The measurement range of this detector is 0 - 1500 W / m 2 , and the resolution is 1 W / m 2 .

[0071] After a large number of verifications, the change trend of the photovoltaic output power is basically synchronized with the irradiance. The photovoltaic-thermoelectric coupling system has the same characteristics. The output power of photovoltaic power generation is proportional to the irradiance and increases with the increase of the irradiance.

[0072] Therefore, through the formula, the approximate position of the maximum output power of the photovoltaic-thermoelectric coupling system under the current environmental irradiance can be obtained.

[0073] The short-circuit current I sc , the open-circuit voltage V oc , the maximum power point current I m and the maximum power point voltage V m are usually the standard condition data provided by the battery manufacturer, that is, the measured values under the conditions that the irradiance G is 1000 W / m 2 and the working temperature of the photovoltaic cell is 300 K. 1000 W / m 2 is the standard condition value G ref of the irradiance. In this embodiment, the influence of the irradiance is mainly considered.

[0074] When the irradiance is not the standard condition value, first calculate the irradiance difference ΔG between the real-time obtained irradiance value and the standard condition value G ref of the irradiance difference ΔG.

[0075] ΔG = G - G ref

[0076] The output current and output voltage of the photovoltaic cell will change with the change of irradiance.

[0077] I s ' c = I sc (1 + aΔT)G / G ref

[0078] V o ' c = V oc (1 - cΔT)ln(e + bΔG)

[0079] I' m = I m (1 + aΔT)G / G ref

[0080] V m ' = V m (1 - cΔT)ln(e + bΔG)

[0081] ΔT = T - T ref

[0082] In the formula, V o ' c is the open-circuit voltage at the irradiance value G and temperature T obtained in real time, V; I s ' c is the short-circuit current under actual conditions, A; V m ' is the actual maximum power point voltage, V; I' m is the actual maximum power point current, A; e is the natural logarithm, approximately 2.71828; a, b, c are compensation coefficients, a = 0.0025 / K, b = 0.0005 / (W / m 2 )), c = 0.00288 / K. T is the actual temperature of the battery, T ref is the standard condition temperature of the battery, 300K.

[0083] Expression of the output characteristics of the photovoltaic cell:

[0084]

[0085] V max = V m ·ln(e + 0.0005ΔG)(1 - 0.00288ΔT)

[0086] Wherein, I m is the maximum output current under standard conditions, in A; V m is the maximum output voltage under standard conditions, in V; I max is the maximum current actually output by the photovoltaic cell, in A; V max is the maximum voltage actually output by the photovoltaic cell, in V, and △T is the difference between the actual temperature of the cell and the standard temperature of the cell.

[0087] Therefore, the maximum output power P of the photovoltaic-thermoelectric coupling system max can be expressed as:

[0088] P max = I max ·V max

[0089] It can be seen that the irradiance is positively correlated with the photovoltaic power generation power and highly correlated.

[0090] In the open-circuit state, the photocurrent I ph is the current generated by the reverse saturation current I0 of the diode:

[0091]

[0092] wherein, n is the diode quality factor, usually between 1 and 2; V oc is the open-circuit voltage; q is the electron charge.

[0093] When V oc is relatively large, the exponential term is much greater than 1 and can be simplified to:

[0094]

[0095] The photocurrent I ph is proportional to the irradiance G, that is:

[0096] I ph = K·G

[0097] where K is a constant related to the cell area, quantum efficiency, etc.

[0098] It can be obtained that:

[0099]

[0100] where k is the Boltzmann constant.

[0101] Simplified, assuming that the temperature is constant and I0 remains unchanged, the open-circuit voltage when the irradiance changes can be approximated as:

[0102]

[0103] where G STC = 1000 W / m2 is the irradiance under standard test conditions (STC), V oc,STC is the open circuit voltage under corresponding conditions.

[0104] In this embodiment, according to the ambient irradiance, the theoretical reference value of the output voltage that maximizes the system output power is determined; the theoretical reference value of the output voltage is increased and decreased by a set ratio to obtain the output voltage range.

[0105] The theoretical reference value of the output voltage V mp is:

[0106]

[0107] where k0 is the correction coefficient, T is the actual temperature of the battery, V t is the thermal voltage.

[0108] Combining the above formulas, the theoretical reference value of the output voltage V when the system output power is maximized can be obtained mp . The calculated theoretical reference value of the output voltage V mp is increased and decreased by a set ratio to obtain the theoretical maximum value and the theoretical minimum value of the output voltage. The output voltage range is greater than or equal to the theoretical minimum value of the output voltage and less than or equal to the theoretical maximum value of the output voltage.

[0109] The set ratio is preferably 10%.

[0110] Using the above formula, the approximate power point of the current irradiance can be judged. Then, based on this approximate power point, a smaller voltage range can be obtained, and finally, the maximum power point can be approached with a small step size. This method can greatly improve the efficiency of traditional maximum power point tracking (MPPT).

[0111] After that, it is judged whether the output voltage is within the output voltage range;

[0112] When the output voltage is not within the output voltage range, the output voltage is adjusted until the adjusted output voltage is within the output voltage range.

[0113] When the output voltage is within the output voltage range, with the goal of maximizing the output power, the cuckoo algorithm is used to search within the output voltage range to determine the optimal output voltage.

[0114] In this embodiment, the output voltage of the system is adjusted by changing the duty cycle. Therefore, when determining the optimal output voltage, the duty cycle corresponding to the optimal output voltage is also determined as the optimal duty cycle; the system is controlled according to the optimal duty cycle to make the system stable at the maximum power point.

[0115] Specifically, the cuckoo algorithm in this embodiment determines the optimal output voltage by searching the duty cycle, and determines the optimal duty cycle while determining the optimal output voltage.

[0116] The cuckoo algorithm is particularly suitable for solving complex optimization problems, such as function optimization, combinatorial optimization, etc. Through a random selection and replacement mechanism, it can better perform global search and avoid being troubled by local optimal solutions. At the same time, the cuckoo algorithm exhibits a relatively fast convergence speed and is applicable to most continuous optimization problems. Its implementation process is relatively simple and is very suitable for beginners to understand and use.

[0117] This algorithm is based on three idealized rules:

[0118] 1. Each cuckoo lays one egg and deposits it in a randomly selected nest.

[0119] 2. The number of nests is fixed, and the probability of a cuckoo's egg being discovered is P(a).

[0120] 3. High-quality available nests will be retained for the next generation.

[0121] The cuckoo algorithm has a relatively fast iteration speed and global search ability.

[0122] The position path update formula of the cuckoo algorithm is as follows.

[0123]

[0124] In the formula is the position of the i-th nest in the t-th generation; ⊕ is the point-to-point multiplication; α is the control quantity of the search range and follows a normal distribution.

[0125] In the formula, L(λ) is the random search path of Levy flight. Levy flight can simulate the flight trajectory of birds, including high-frequency short-step flights and low-frequency long-step flights, and the random step size follows the Levy distribution.

[0126] L(s,λ)≈s -λ

[0127] In the formula, s is the random step size of Levy flight.

[0128] Due to the random characteristics of Levy flight, the step size needs to be changed to handle the local optimal problem. Using short-step flights for search near local extreme points can improve the search accuracy, and using long-step flights for periodic search when far from local optimal points can reduce the probability of encountering local extreme values.

[0129] In MPPT control, the cuckoo algorithm is used for control, and the duty cycle in the DC conversion circuit is as shown in the formula.

[0130]

[0131] Where d is the duty cycle, t is the number of iterations, and i is the current number of cuckoos. Is the optimal duty cycle when the number of iterations is t.

[0132] The simplified scheme of Levy flight is as shown in the formula.

[0133]

[0134] After all iterations are completed, the algorithm stops. The condition for restarting the cuckoo algorithm is that the system output power changes and is greater than the preset value. The global optimal duty cycle given by the algorithm after completing the iteration is as shown in the formula.

[0135]

[0136] Where P is the system output power, d is the duty cycle, t is the number of iterations, and i is the current number of cuckoos.

[0137] Using the cuckoo algorithm can effectively improve the power generation efficiency of the photovoltaic-thermoelectric coupling system.

[0138] The process of further adjusting the output voltage of the photovoltaic-thermoelectric coupling system using the cuckoo algorithm in this embodiment includes:

[0139] Initializing the photovoltaic-thermoelectric coupling system, including setting the parameters of the photovoltaic-thermoelectric coupling system, the photothermal conversion device, the thermoelectric conversion device, and the control unit. At the same time, determine the parameters such as the initial population, the number of iterations, and the search step size of the cuckoo search algorithm. In addition, an irradiance sensor needs to be installed to monitor the change of irradiance on the surface of the photovoltaic-thermoelectric coupling system in real time. This irradiance sensor can be a portable gas detector JXBS-3001-ZFS.

[0140] Real-time collect the output voltage, output current, the working state data of the photothermal conversion device and the thermoelectric conversion device, and the data of the irradiance sensor of the photovoltaic-thermoelectric coupling system. These data will be used to calculate the output power of the system and update the population of the cuckoo search algorithm.

[0141] According to the collected system data, first calculate the output voltage range from the irradiance, and then within the output voltage range, use the cuckoo algorithm to track the maximum power point in a small range to improve the efficiency.

[0142] Calculate the fitness value of each cuckoo (i.e., each solution), that is, the output power of the system under this solution. This output power is equal to the output voltage multiplied by the output current. Take the duty cycle corresponding to the maximum output power as the optimal duty cycle, and when the working voltage reaches the optimal working voltage, take the output voltage corresponding to the maximum output power as the optimal output voltage.

[0143] According to the fitness value, the cuckoo population is updated. A new cuckoo position is generated and its fitness value is calculated. If the fitness value of the new position is higher than the current optimal solution, the optimal solution is updated. At the same time, according to the change of irradiance, the search step size and search range of the cuckoo search algorithm are dynamically adjusted to improve the search efficiency.

[0144] Check whether the number of iterations reaches the preset maximum value, or whether the fitness value of the optimal solution reaches the preset accuracy requirement. If any of these conditions are met, the iteration is terminated and the optimal solution is output, which is the optimal duty cycle; otherwise, return to the step of updating the cuckoo population and continue iterating.

[0145] According to the optimal solution and irradiance data, the parameters of the photovoltaic-thermoelectric coupling system, such as the output voltage of the photovoltaic-thermoelectric coupling system and the operating temperature of the photothermal conversion device, are adjusted to achieve maximum power point tracking. At the same time, according to the change of irradiance, the control strategy of the system is dynamically adjusted to maintain efficient and stable operation of the system.

[0146] In practical applications, it is necessary to monitor the system's operating status and output power, as well as changes in ambient irradiance in real time. If the external environment changes (such as a sudden decrease in irradiance), the MPPT control process needs to be re-performed to ensure that the system always operates at the maximum power point. At the same time, according to the actual operation of the system, the parameters of the cuckoo search algorithm are fine-tuned to improve search efficiency and accuracy.

[0147] This embodiment reveals the influence mechanism of irradiance on the working characteristics of the photovoltaic-thermoelectric coupling system, and establishes a maximum power point tracking scheme for the photovoltaic-thermoelectric coupling system with the participation of irradiance; studies the MPPT control algorithm of the photovoltaic-thermoelectric coupling system with the participation of irradiance, and greatly improves the MPPT efficiency through an integrated power tracking control strategy for the photovoltaic-thermoelectric coupling system integrating irradiance parameters; based on intelligent control theory and the energy transfer mechanism of the photovoltaic-thermoelectric coupling system, a new integrated power tracking control mode for the photovoltaic-thermoelectric coupling system is constructed that takes into account both high irradiance reception and maximum power point tracking.

[0148] The present embodiment discloses a maximum power point tracking control method for a photovoltaic-thermoelectric coupling system, which uses a variable step size strategy to adjust the output voltage, thereby improving the tracking efficiency while ensuring the maximum power point tracking accuracy.

[0149] Example 2

[0150] In this embodiment, a photovoltaic-thermoelectric coupling system maximum power point tracking control system is disclosed, comprising:

[0151] A data acquisition unit, used to acquire the ambient irradiance, output voltage and output current in real time;

[0152] An output power calculation unit for determining output power according to the output voltage and output current;

[0153] An output voltage range determination unit for determining an output voltage range according to the ambient irradiance;

[0154] An output voltage adjustment unit for adjusting the output voltage to a post-adjustment output voltage within the output voltage range when the output voltage is not within the output voltage range;

[0155] A maximum power point holding unit for determining, from within the output voltage range, the output voltage that maximizes the system output power as the optimal output voltage; and controlling the system according to the optimal output voltage to keep the system stable at the maximum power point.

[0156] The present invention also discloses a computer device, which includes:

[0157] A processor adapted to execute a computer program;

[0158] A computer-readable storage medium having stored therein a computer program, which when executed by the processor, implements a method for maximum power point tracking control of a photovoltaic-thermoelectric coupled system disclosed in Embodiment 1.

[0159] The present invention also discloses a computer-readable storage medium storing a computer program, which is adapted to be loaded and executed by a processor to implement a method for maximum power point tracking control of a photovoltaic-thermoelectric coupled system disclosed in Embodiment 1.

[0160] The present invention also discloses a computer program product, which includes a computer program, which when executed by a processor, implements a method for maximum power point tracking control of a photovoltaic-thermoelectric coupled system disclosed in Embodiment 1.

[0161] The method disclosed in Embodiment 1 can be directly embodied as being executed by a hardware processor, or by a combination of hardware and software modules in the processor. The software modules can be located in mature storage media in the art such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, registers, etc. This storage medium is located in the memory, and the processor reads the information in the memory and combines it with its hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0162] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with this embodiment can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0163] Although the specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that based on the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. A maximum power point tracking control method for a photovoltaic-thermoelectric coupling system, characterized in that: include: Obtain environmental irradiance, output voltage and output current in real time; Determine the output power according to the output voltage and output current; Determine the output voltage range according to the ambient irradiance; When the output voltage is not within the output voltage range, the output voltage is adjusted until the adjusted output voltage is within the output voltage range; Obtain the output power after adjusting the output voltage; Calculate the error between the output power after adjusting the output voltage and the output power at the previous moment; When the error between the two output powers is greater than a preset value, the output voltage is further adjusted until the error between the output power after the further adjustment of the output voltage and the output power at the previous moment is less than a preset value, so that the system is stabilized at the maximum power point.

2. A photovoltaic-thermoelectric coupling system maximum power point tracking control method as claimed in claim 1, characterized in that: According to the ambient irradiance, a theoretical reference value of the output voltage that maximizes the system output power is determined; the theoretical reference value of the output voltage is increased or decreased by a set ratio to obtain an output voltage range.

3. A photovoltaic-thermoelectric coupling system maximum power point tracking control method as claimed in claim 1, characterized in that: With the goal of maximizing output power, the cuckoo algorithm is used to search and determine the optimal output voltage within the output voltage range.

4. A photovoltaic-thermoelectric coupling system maximum power point tracking control method as claimed in claim 1, characterized in that: Determine the duty cycle corresponding to the optimal output voltage as the optimal duty cycle; The system is controlled according to the optimal duty cycle to stabilize the system at the maximum power point.

5. A photovoltaic-thermoelectric coupling system maximum power point tracking control method as claimed in claim 1, characterized in that: The cuckoo algorithm determines the optimal output voltage by searching the duty cycle, and determines the optimal duty cycle while determining the optimal output voltage.

6. A photovoltaic-thermoelectric coupling system maximum power point tracking control method as claimed in claim 1, characterized in that: When the output voltage is within the output voltage range, the output voltage that maximizes the output power is directly determined from the output voltage range as the optimal output voltage.

7. A maximum power point tracking control system for a photovoltaic-thermoelectric coupling system, characterized in that: include: A data acquisition unit, used to acquire the ambient irradiance, output voltage and output current in real time; An output power calculation unit, used to determine the output power according to the output voltage and the output current; An output voltage range determination unit, used to determine the output voltage range according to the ambient irradiance; An output voltage adjustment unit, used for adjusting the output voltage until the adjusted output voltage is within the output voltage range when the output voltage is not within the output voltage range; The maximum power point holding unit is used to determine the output voltage that maximizes the system output power from the output voltage range as the optimal output voltage; according to the optimal output voltage, the system is controlled to stabilize the system at the maximum power point.

8. An electronic device, characterized in that: The device comprises: a processor adapted to execute a computer program; A computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium, and when the computer program is executed by the processor, a maximum power point tracking control method for a photovoltaic-thermoelectric coupling system according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is suitable for being loaded by a processor and executing the maximum power point tracking control method for a photovoltaic-thermoelectric coupling system according to any one of claims 1 to 6.

10. A computer program product, characterized in that The computer program product includes a computer program, and when the computer program is executed by a processor, the maximum power point tracking control method for a photovoltaic-thermoelectric coupling system according to any one of claims 1 to 6 is implemented.

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