Maximum power point tracking method, device, system and control module

Abstract

The present application relates to the technical field of maximum power point tracking, and discloses a maximum power point tracking method, device, system and control module, the method comprising: determining the current output voltage and the current output current according to the output voltage and the output current collected by the output acquisition circuit, determining the output voltage change ratio and the output current change ratio according to the current output voltage, the current output current and the last output voltage and the last output current; judging whether the absolute value of the output voltage change ratio is less than the first set value and the absolute value of the output current change ratio is less than the second set value; if so, maintaining the adjustment direction of the photovoltaic panel working voltage; if not, regulating the adjustment direction of the photovoltaic panel working voltage according to the output voltage change ratio and the output current change ratio; judging whether it is at the maximum power point or whether the maximum power point flag is valid, and executing the next cycle according to the judgment result. The present application splits the power into voltage and current for judgment, and improves the judgment accuracy of the interference observation method.

Description

Technical Field

[0001] The present application relates to the technical field of maximum power point tracking, and in particular to a maximum power point tracking method, device, system and control module. Background Art

[0002] According to the VI curve characteristics of photovoltaic panels, photovoltaic panels have a maximum power point, and when they are at this maximum power point, the photovoltaic panels can output more electrical energy. Therefore, applying MPPT (Maximum Power Point Tracking) to the solar charge controller can make more full use of the electrical energy generated by photovoltaic panels.

[0003] At present, when using the interference observation method for maximum power point tracking, the output power of the solar panel this time is generally compared with the previous one to determine whether to increase or decrease the working voltage of the solar panel to achieve MPPT. Among them, the output power of the solar panel is determined based on the collected current and voltage by collecting the output current and output voltage of the solar panel through the collection circuit. However, due to errors in the collection circuit itself, the voltage and current collected by the collection circuit have deviations, which makes it easy to make misjudgments when power is used as the judgment condition.

[0004] In summary, how to improve the judgment accuracy of the interference observation method is a technical problem that needs to be urgently solved by those skilled in the art. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a maximum power point tracking method, device, system and control module for improving the judgment accuracy of the interference observation method.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] A maximum power point tracking method is applied to a control module, wherein the control module is connected to a voltage regulation circuit and an output acquisition circuit, the output acquisition circuit is connected between the voltage regulation circuit and a load, and the voltage regulation circuit is connected to a photovoltaic panel. The maximum power point tracking method comprises: determining a current output voltage and a current output current according to the output voltage and the output current acquired by the output acquisition circuit within a preset timing execution time, determining an output voltage change ratio according to the current output voltage and the last output voltage, and determining an output current change ratio according to the current output current and the last output current; and judging whether the absolute value of the output voltage change ratio is less than a first set value and the absolute value of the output current change ratio is less than a second set value. value; if yes, maintain the adjustment direction of the working voltage of the photovoltaic panel, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; if not, regulate the adjustment direction of the working voltage of the photovoltaic panel according to the output voltage change ratio and the output current change ratio, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; determine whether it is at the maximum power point or whether the maximum power point flag is valid, determine the preset timing execution time according to the judgment result, and after reaching the preset timing execution time, return to execute the step of determining the output voltage and the output current corresponding to the output voltage and the output current collected by the output collection circuit within the preset timing execution time.

[0008] Optionally, maintaining the adjustment direction of the working voltage of the photovoltaic panel, and adjusting the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel, including: maintaining the first duty cycle adjustment state in the previous cycle, obtaining the first duty cycle adjustment state in this cycle, obtaining the current PWM signal according to the first duty cycle adjustment state in this cycle, and adjusting the output power of the voltage regulation circuit according to the current PWM signal to adjust the working voltage of the photovoltaic panel;

[0009] According to the output voltage change ratio and the output current change ratio, the adjustment direction of the working voltage of the photovoltaic panel is regulated, and according to the adjustment direction of the working voltage of the photovoltaic panel, the working voltage of the photovoltaic panel is adjusted, including: according to the output voltage change ratio, the output current change ratio and the first duty cycle adjustment state in the previous cycle, the first duty cycle adjustment state in this cycle is obtained, according to the first duty cycle adjustment state in this cycle, the current PWM signal is obtained, and according to the current PWM signal, the output power of the voltage regulation circuit is adjusted to adjust the working voltage of the photovoltaic panel;

[0010] The first duty cycle adjustment state includes increasing and decreasing.

[0011] Optionally, the first duty cycle adjustment state in this cycle is obtained according to the output voltage change ratio, the output current change ratio and the first duty cycle adjustment state in the previous cycle, including: judging whether the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio; if so, maintaining the first duty cycle adjustment state in the previous cycle to obtain the first duty cycle adjustment state in this cycle; if not, when the first duty cycle adjustment state in the previous cycle is increasing, the first duty cycle adjustment state in this cycle is decreasing, and when the first duty cycle adjustment state in the previous cycle is decreasing, the first duty cycle adjustment state in this cycle is increasing.

[0012] Optionally, the PWM signal of this time is obtained according to the first duty cycle adjustment state in this cycle, including: if the first duty cycle adjustment state in this cycle is increasing, then judging whether the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle value; if the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle value, then determining that the duty cycle in the PWM signal of this time is equal to the maximum duty cycle value; if the sum of the current duty cycle and the duty cycle adjustment value is not greater than the maximum duty cycle value, then determining that the duty cycle in the PWM signal of this time is equal to the maximum duty cycle value. The duty ratio is equal to the sum of the current duty cycle and the duty cycle adjustment value; if the first duty cycle adjustment state in this cycle is decreasing, then determine whether the difference between the current duty cycle and the duty cycle adjustment value is less than the minimum duty cycle value; if the difference between the current duty cycle and the duty cycle adjustment value is less than the minimum duty cycle value, then determine that the duty cycle in this PWM signal is equal to the minimum duty cycle value; if the difference between the current duty cycle and the duty cycle adjustment value is not less than the minimum duty cycle value, then determine that the duty cycle in this PWM signal is equal to the difference between the current duty cycle and the duty cycle adjustment value.

[0013] Optionally, judging whether it is at the maximum power point or whether the maximum power point flag is valid, and determining the preset timing execution time according to the judgment result, includes: judging whether the maximum power point flag is valid; if the maximum power point flag is invalid, judging whether it is at the maximum power point; if it is not at the maximum power point, determining the preset timing execution time as the first timing execution time; if it is at the maximum power point, marking the maximum power point flag as valid, and determining the preset timing execution time as the second timing execution time; if the maximum power point flag is valid, determining the preset timing execution time as the second timing execution time;

[0014] The second scheduled execution time is greater than the first scheduled execution time.

[0015] Optionally, if it is determined that the maximum power point flag is valid, before determining that the preset timing execution time is the second timing execution time, it also includes: judging whether the maximum power point flag should be invalid; if so, updating the maximum power point flag to invalid, and determining the preset timing execution time to be the first timing execution time; if not, executing the step of determining the preset timing execution time to be the second timing execution time.

[0016] Optionally, the control module is also connected to an input acquisition circuit, and the input acquisition circuit is connected between the photovoltaic panel and the voltage regulation circuit. Before determining whether the maximum power point flag should be invalid, it also includes: determining the current input voltage and the current input current according to the input voltage and the input current collected by the input acquisition circuit within the preset timing execution time, determining the input voltage change ratio according to the current input voltage and the last input voltage, and determining the input current change ratio according to the current input current and the last input current;

[0017] Determining whether the maximum power point flag should be invalid includes: determining whether the absolute value of the input voltage change ratio is not less than a third set value or the absolute value of the input current change ratio is not less than a fourth set value, or, whether the following occurs N1 times in succession: the absolute value of the output voltage change ratio is not less than the first set value, the absolute value of the output current change ratio is not less than at least one of the second set value, and the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio; N1 is an integer greater than 0; if so, determining that the maximum power point flag should be invalid; if not, determining that the maximum power point flag should not be invalid.

[0018] Optionally, the current input voltage and the current input current are determined according to the input voltage and the input current collected by the input acquisition circuit within the preset timing execution time, including: preprocessing the input voltage and the input current collected by the input acquisition circuit within the preset timing execution time, determining the current input voltage according to the preprocessed input voltage, and determining the current input current according to the preprocessed input current.

[0019] Optionally, after determining the input voltage change ratio according to the current input voltage and the last input voltage, and determining the input current change ratio according to the current input current and the last input current, it also includes: if the absolute value of the input voltage change ratio is not less than the fifth set value, updating the last input voltage with the current input voltage; if the absolute value of the input voltage change ratio is less than the fifth set value, maintaining the last input voltage; if the absolute value of the input current change ratio is not less than the sixth set value, updating the last input current with the current input current; if the absolute value of the input current change ratio is less than the corresponding sixth set value, maintaining the last input current.

[0020] Optionally, if it is determined that the sum of the output voltage change ratio and the output current change ratio is less than the inverse of the product of the output voltage change ratio and the output current change ratio, before obtaining the first duty cycle adjustment state in this cycle, the method further includes: assigning the second duty cycle adjustment state to the third duty cycle adjustment state, and assigning the first duty cycle adjustment state to the second duty cycle adjustment state;

[0021] Determining whether it is at the maximum power point includes: determining whether the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and whether the third duty cycle adjustment state is equal to the first duty cycle adjustment state; if so, controlling n to add 1, and determining whether n is greater than or equal to N2, if n is greater than or equal to N2, determining that it is at the maximum power point, if n is less than N2, controlling n to be equal to 0 and determining that it is not at the maximum power point; n is the number of consecutive occurrences of the second duty cycle adjustment state being not equal to the third duty cycle adjustment state and the third duty cycle adjustment state being equal to the first duty cycle adjustment state, and N2 is an integer greater than 0; if not, controlling n to be equal to 0 and determining that it is not at the maximum power point.

[0022] Optionally, the current output voltage and the current output current are determined according to the output voltage and the output current collected by the output acquisition circuit within the preset timing execution time, including: preprocessing the output voltage and the output current collected by the output acquisition circuit within the preset timing execution time, determining the current output voltage according to the preprocessed output voltage, and determining the current output current according to the preprocessed output current.

[0023] Optionally, the output voltage and output current collected by the output acquisition circuit within the preset timing execution time are preprocessed, and the current output voltage is determined based on the preprocessed output voltage, and the current output current is determined based on the preprocessed output current, including: using a median average filtering algorithm to process the output voltage and output current collected by the output acquisition circuit within the preset timing execution time to obtain the current output voltage and the current output current accordingly.

[0024] Optionally, after determining the output voltage change ratio according to the current output voltage and the last output voltage, and determining the output current change ratio according to the current output current and the last output current, it also includes: if the absolute value of the output voltage change ratio is not less than a first set value, updating the last output voltage with the current output voltage; if the absolute value of the output voltage change ratio is less than the first set value, maintaining the last output voltage; if the absolute value of the output current change ratio is not less than a second set value, updating the last output current with the current output current; if the absolute value of the output current change ratio is less than the corresponding second set value, maintaining the last output current.

[0025] A maximum power point tracking device is applied to a control module, wherein the control module is connected to a voltage regulation circuit and an output acquisition circuit, the output acquisition circuit is connected between the voltage regulation circuit and a load, and the voltage regulation circuit is connected to a photovoltaic panel. The maximum power point tracking device comprises: a determination module, which is used to determine the current output voltage and the current output current according to the output voltage and the output current collected by the output acquisition circuit within a preset timing execution time, determine the output voltage change ratio according to the current output voltage and the last output voltage, and determine the output current change ratio according to the current output current and the last output current; a first judgment module, which is used to judge whether the absolute value of the output voltage change ratio is less than a first set value and the absolute value of the output current change ratio is less than a second set value; if yes, maintain the adjustment direction of the working voltage of the photovoltaic panel, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; if not, regulate the adjustment direction of the working voltage of the photovoltaic panel according to the output voltage change ratio and the output current change ratio, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; a second judgment module, used to judge whether it is at the maximum power point or whether the maximum power point flag is valid, determine the preset timing execution time according to the judgment result, and return to execute the step of determining the output voltage and the output current corresponding to the output voltage and the output current collected by the output acquisition circuit within the preset timing execution time after reaching the preset timing execution time.

[0026] A maximum power point tracking system comprises an output acquisition circuit connected between a voltage regulation circuit and a load, and a control module connected to the output acquisition circuit and the voltage regulation circuit, wherein the voltage regulation circuit is connected to a photovoltaic panel; the output acquisition circuit is used to acquire the output voltage and output current of the voltage regulation circuit; and the control module is used to implement the steps of the maximum power point tracking method as described in any one of the above items.

[0027] Optionally, it also includes an input acquisition circuit connected between the photovoltaic panel and the voltage regulation circuit and connected to the control module; the input acquisition circuit is used to collect the input voltage and input current of the voltage regulation circuit.

[0028] Optionally, the control module includes an MCU and a driving circuit connected between the MCU and the voltage regulation circuit. The MCU determines a first duty cycle adjustment state in this cycle, and adjusts the current PWM signal according to the first duty cycle adjustment state in this cycle to achieve regulation of the working voltage of the photovoltaic panel.

[0029] A control module, wherein the control module is connected to a voltage regulation circuit and an output acquisition circuit, the output acquisition circuit is connected between the voltage regulation circuit and a load, and the voltage regulation circuit is connected to a photovoltaic panel; the control module is used to implement the steps of the maximum power point tracking method as described in any one of the above items.

[0030] The present application provides a maximum power point tracking method, device, system and control module, wherein the method is applied to the control module, the control module is connected to the voltage regulation circuit and the output acquisition circuit, the output acquisition circuit is connected between the voltage regulation circuit and the load, and the voltage regulation circuit is connected to the photovoltaic panel. The method includes: determining the current output voltage and the current output current according to the output voltage and the output current collected by the output acquisition circuit within a preset timing execution time, determining the output voltage change ratio according to the current output voltage and the previous output voltage, and determining the output current change ratio according to the current output current and the previous output current; judging whether the absolute value of the output voltage change ratio is less than the first set value and the output current change ratio is less than the first set value. The absolute value of the value is less than the second set value; if so, maintain the adjustment direction of the working voltage of the photovoltaic panel, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; if not, regulate the adjustment direction of the working voltage of the photovoltaic panel according to the output voltage change ratio and the output current change ratio, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; determine whether it is at the maximum power point or whether the maximum power point flag is valid, determine the preset timing execution time according to the judgment result, and return to execute the step of determining the output voltage and the output current corresponding to the output voltage and the output current collected by the output collection circuit within the preset timing execution time after the preset timing execution time is reached.

[0031] The above technical solution disclosed in the present application determines whether the absolute value of the output voltage change ratio is less than the first set value and the absolute value of the output current change ratio is less than the second set value in each cycle. If the absolute value of the output voltage change ratio is less than the corresponding first set value and the absolute value of the output current change ratio is less than the corresponding second set value, it indicates that the changes in the output voltage and the output current are both within their respective error ranges. At this time, the adjustment direction of the working voltage of the photovoltaic panel is maintained to avoid the sampling error interfering with the maximum power point tracking. If the absolute value of the output voltage change ratio is not less than the corresponding first set value and / or the absolute value of the output current change ratio is not less than the corresponding second set value, it indicates that the change in at least one of the output voltage and the output current exceeds the error range. At this time, the output voltage change ratio and the output current change ratio can be used to indirectly determine the changes in the output power and the input power (i.e., the output power of the photovoltaic panel) of the voltage regulation circuit, so as to regulate the adjustment direction of the working voltage of the photovoltaic panel based on the power changes. Compared with the existing interference observation method for determining power, the present application improves the interference observation method by splitting the power into voltage and current, and using the voltage change ratio and the corresponding first set value, the current change ratio and the corresponding second set value for determination, so as to reduce the interference of errors and improve the determination accuracy of the interference observation method.

[0032] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of the IV curve of a photovoltaic panel;

[0034] Figure 2 A schematic diagram of the structure of a maximum power point tracking system provided in an embodiment of the present application;

[0035] Figure 3 A flowchart of a maximum power point tracking method provided in an embodiment of the present application;

[0036] Figure 4 A flowchart of another maximum power point tracking method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] According to the IV curve characteristics of the photovoltaic panel, the photovoltaic panel has a maximum power point, such as Figure 1 As shown, it shows a schematic diagram of the IV curve of a photovoltaic panel, wherein the horizontal axis is voltage and the vertical axis is current, V OC is the open circuit voltage of the photovoltaic panel, I SC is the short-circuit current of the photovoltaic panel, I m is the optimal operating current of the photovoltaic panel, Vm is the optimal operating voltage of the photovoltaic panel, (I m ,V m ) is the maximum power point of the photovoltaic panel. When at this maximum power point, the photovoltaic panel can output more electrical energy. Therefore, applying MPPT in photovoltaics can make more full use of the electrical energy generated by photovoltaic panels.

[0038] At present, the three common MPPT algorithms are: constant voltage tracking method, conductance increment method and interference observation method. The traditional interference observation method is to achieve MPPT by comparing the current output power of the photovoltaic panel with the previous output power to determine whether to increase or decrease the working voltage of the photovoltaic panel. Specifically, at a certain moment t1, the output power of the photovoltaic panel is P1 (P1 is obtained based on the voltage and current at that moment), and the processor outputs a signal to increase or decrease the working voltage of the photovoltaic panel. After a period of time Δt, at time t2 (t2=t1+Δt), the output power of the solar panel is detected to be P2 (P2 is obtained based on the voltage and current at that moment). When the working voltage of the photovoltaic panel increases (that is, when ΔV is positive, ΔV=V2-V1), if ΔP (ΔP=P2-P1) is positive, the working voltage of the photovoltaic panel should continue to increase until ΔP=0, and if ΔP is negative, the working voltage of the photovoltaic panel should be reduced until ΔP=0. When the working voltage of the photovoltaic panel decreases (that is, when ΔV is negative), if ΔP is positive, the working voltage of the photovoltaic panel should continue to decrease until ΔP = 0. If ΔP is negative, the working voltage of the photovoltaic panel should be increased until ΔP = 0. Among them, the corresponding ΔV should be selected with a suitable value. If the value of ΔV is too large, the output of the photovoltaic panel will float around the maximum power point. If the value of ΔV is too small, it will take more time, and the effect will deteriorate when the maximum power point changes frequently.

[0039] In practical applications, the power used in the interference observation method is usually obtained by collecting voltage and current data through a common and simple acquisition circuit, and then indirectly obtaining power through multiplication. Since the data obtained by the processing unit and the acquisition circuit will deviate from the actual data (the acquisition circuit itself has errors, and there are also certain interferences in the acquisition circuit, and a series of factors such as the external environment cause the final data to fluctuate), the corresponding power will have voltage and current errors. Therefore, if power is used as a judgment condition, misjudgment will occur, reducing the judgment accuracy of the interference observation method.

[0040] To this end, the present application provides a maximum power point tracking method, device, system and control module for improving the judgment accuracy of the interference observation method.

[0041] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0042] See also Figure 2 and Figure 3 ,in, Figure 2 A schematic diagram of the structure of a maximum power point tracking system provided in an embodiment of the present application is shown. Figure 3 A flowchart of a maximum power point tracking method provided by an embodiment of the present application is shown. A maximum power point tracking method provided by an embodiment of the present application is applied to a control module, the control module is connected to a voltage regulation circuit and an output acquisition circuit, the output acquisition circuit is connected between the voltage regulation circuit and the load, the voltage regulation circuit is connected to a photovoltaic panel, and the maximum power point tracking method may include:

[0043] S11: Determine the current output voltage and the current output current according to the output voltage and the output current collected by the output collection circuit within the preset timing execution time, determine the output voltage change ratio according to the current output voltage and the previous output voltage, and determine the output current change ratio according to the current output current and the previous output current.

[0044] The maximum power point tracking method provided in the embodiment of the present application can be applied to the control module. Figure 2As shown, the control module is connected to the voltage regulation circuit, the input end of the voltage regulation circuit is connected to the photovoltaic panel, and the output end of the voltage regulation circuit is connected to the load. The control module is used to adjust the output power of the voltage regulation circuit by adjusting the duty cycle in the PWM signal. Accordingly, the input power of the voltage regulation circuit will also change (that is, the output power of the photovoltaic panel will change, that is, the working voltage of the photovoltaic panel will change). The control module can specifically include an MCU (Micro Control Unit) and a drive circuit connected to the MCU and the voltage regulation circuit. The MCU can send a PWM (Pulse Width Modulation) signal (the signal contains the duty cycle parameter) to the drive circuit, and the drive circuit enhances the PWM signal and sends it to the voltage regulation circuit to regulate the output power of the voltage regulation circuit. Of course, other forms of control modules can also be used to regulate the duty cycle in the PWM signal. The voltage regulation circuit is used to adjust the output voltage (or working voltage) of the photovoltaic panel to meet the voltage requirements of the load. The voltage regulation circuit can be a BUCK DCDC (DC to DC) step-down circuit or a BOOST DCDC step-up circuit. The specific voltage regulation circuit is selected according to the output of the photovoltaic panel and the requirements of the load. It should be noted that the aforementioned loads can be batteries, water pumps, etc., which are determined according to the application scenario of the photovoltaic panel. In addition, Figure 2 The solid lines in the figure represent power lines, and the half-dashed lines represent signal lines.

[0045] Furthermore, considering that the power is generally calculated based on the output of the voltage regulating circuit, the current acquisition cost on the input side of the voltage regulating circuit is relatively high, the input power of the voltage regulating circuit is lossy and the loss is not fixed (the input power is lossy due to the power self-loss of the voltage regulating circuit, and the self-loss is not fixed), etc., in order to reduce the cost and improve the accuracy of the maximum power point tracking and determination, the embodiment of the present application sets an output acquisition circuit between the output side of the voltage regulating circuit and the load (that is, the output acquisition circuit is connected between the voltage regulating circuit and the load), and uses the output acquisition circuit to acquire the output voltage and output current of the voltage regulating circuit, and the output acquisition circuit is also connected to the control module. The output acquisition circuit can specifically be an output voltage and current acquisition circuit, which is used to acquire the output voltage and output current of the voltage regulating circuit (the output acquisition circuit can specifically acquire the output voltage and output current of the voltage regulating circuit in real time), and the acquired output voltage is scaled based on a preset first voltage scaling ratio to obtain a first scaled voltage, and the acquired output current is scaled based on a preset first current scaling ratio to obtain a first scaled current, and the control module can obtain the first scaled voltage and the first scaled current from the output acquisition circuit on a regular basis or in real time. Among them, the first voltage scaling ratio and the first current scaling ratio can be specifically set accordingly according to the voltage range, current range, etc. that the control module can withstand when designing the output acquisition circuit. The output acquisition circuit scales the collected output voltage and output current so that the voltage and current obtained by the control module from the output acquisition circuit are within the tolerance range of the control module to avoid permanent damage to the control module (that is, the output acquisition circuit is used to convert the actual voltage and current values ​​into data that the control module can accept and recognize). After the control module collects the first scaled voltage and the first scaled current at the output acquisition circuit, it can numerically restore the first scaled voltage and the first scaled current to obtain the output voltage and output current collected by the output acquisition circuit. Specifically, the control module uses the inverse of the first voltage scaling ratio to restore the first scaled voltage to obtain the output voltage collected by the output acquisition circuit, and uses the inverse of the first current scaling ratio to restore the first scaled current to obtain the output current collected by the output acquisition circuit.

[0046] Specifically, in the initial state (i.e., in the first cycle), the control module can collect the parameters of the output acquisition circuit in real time or on a regular basis within the preset timing execution time (the parameters here are the first scaled voltage and the first scaled current mentioned above, and the aforementioned timing time interval is less than the preset timing execution time, that is, the control module can obtain the parameters of the output acquisition circuit multiple times within the preset timing execution time), and calculate the output voltage and output voltage of the voltage regulating circuit collected by the output acquisition circuit within the preset timing execution time based on the parameters of the output acquisition circuit collected within the preset timing execution time. Among them, the preset timing execution time is the duration of the preset timing execution cycle, that is, the interval time between two adjacent cycles. The specific size can be determined by relevant personnel based on experience or through experiments. In the initial case, the preset timing execution time can be the first timing execution time, for example, it can be 40ms. That is, the control module can collect the parameters of the output acquisition circuit, and can record the data collected each time, and can determine whether the timing execution time reaches the preset timing execution time. If the timing execution time does not reach the preset timing execution time, it returns to the step of executing the parameters of the output acquisition circuit. If the timing execution time reaches the preset timing execution time, the output voltage and output current collected by the output acquisition circuit within the preset timing execution time can be calculated according to the parameters of the output acquisition circuit collected at the preset timing execution time. Then, the median average filtering algorithm and other algorithms can be used to pre-process and calculate all the output voltage and output current data collected by the output acquisition circuit within the preset timing execution time to obtain the corresponding output voltage and output current. Then, all the data stored in the cycle can be cleared to reduce the occupation of storage space and facilitate preparation for the next cycle to obtain and process data. That is, in each cycle, the control module obtains the output voltage and output current collected by the output acquisition circuit within the preset timing execution time, and determines the output voltage and output current of this time according to the output voltage and output current collected by the output acquisition circuit within the preset timing execution time. Among them, the specific process of the control module obtaining the output voltage and output current collected by the output acquisition circuit within the preset timing execution time can be: according to the parameters of the output acquisition circuit collected within the preset timing execution time (that is, the first scaling voltage and the first scaling current), the output voltage and output current of the voltage regulation circuit collected by the output acquisition circuit within the preset timing execution time are calculated.

[0047] Among them, the purpose of MPPT is to make the photovoltaic panel output as much power as possible. It is worth noting that the MPPT process can only be carried out when the photovoltaic panel starts to release electrical energy. Therefore, when the photovoltaic panel starts to release electrical energy, it means that power is output to the outside. Only at this time will there be current, and the MPPT process can be carried out (power cannot be calculated when the current is 0, and thus cannot be tracked). Therefore, in each cycle, the control module can first determine whether the output current is equal to 0 after determining the output voltage and output current corresponding to the output voltage and output current collected by the output collection circuit within the preset timing execution time. If the output current is equal to 0, return to the step of collecting the parameters of the output collection circuit within the preset timing execution time and calculating the output voltage and output current collected by the output collection circuit within the preset timing execution time. If the output current is not equal to 0, subsequent operations can be performed to improve the accuracy of the determination of the output voltage and output current, thereby facilitating the improvement of the determination accuracy of the interference observation method (i.e., improving the accuracy of maximum power point tracking).

[0048] Starting from the second cycle, if it is determined that the output current is not equal to 0, the output voltage can be compared with the previous output voltage, and the output voltage change ratio K1 can be obtained by using K1=(this output voltage-last output voltage) / last output voltage. In addition, the output current can be compared with the previous output current, and the output current change ratio K2 can be obtained by using K2=(this output current-last output current) / last output current.

[0049] S12: Determine whether the absolute value of the output voltage change ratio is less than the first set value and the absolute value of the output current change ratio is less than the second set value; if so, execute step S13, if not, execute step S14.

[0050] After determining the output voltage change ratio and the output current change ratio, it is possible to determine whether the absolute value of the output voltage change ratio is less than its corresponding first set value, and whether the absolute value of the output current change ratio is less than its corresponding second set value. That is, it is determined whether |K1| is greater than or equal to its corresponding first set value K 10 , and determine whether |K2| is greater than or equal to its corresponding second set value K 20 Among them, the first setting value K corresponding to |K1| 10 And the second set value K corresponding to |K2| 20 are determined by relevant personnel based on the corresponding acquisition error of the output acquisition circuit, that is, the first set value K corresponding to |K1| 10 Determine the second set value K corresponding to |K2| according to the voltage acquisition error of the output acquisition circuit 20Determined according to the current acquisition error of the output acquisition circuit. Wherein, the first set value K corresponding to |K1| 10 The second setting value K corresponding to |K2| 20 The time intervals may be the same or different. In the embodiment of the present application, the first setting value K corresponding to |K1| 10 The second setting value K corresponding to |K2| 20 Taking 0.5% as an example, the above process is to judge whether |K1| is greater than or equal to 0.5% and to judge whether |K2| is greater than or equal to 0.5%.

[0051] S13: maintaining the adjustment direction of the working voltage of the photovoltaic panel, and adjusting the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel.

[0052] If it is determined that the absolute value of the output voltage change ratio is less than the corresponding first set value and the absolute value of the output current change ratio is less than the corresponding second set value (i.e., if |K1| <K 10 And |K2| <K 20 ), it indicates that the output voltage and the output current may change relative to the previous output voltage and the previous output current due to the acquisition error of the output acquisition circuit, which means that the changes in the output voltage and the output current are within their respective error ranges. At this time, the first duty cycle adjustment state in the previous cycle can be maintained, and the output power of the voltage regulation circuit can be changed by adjusting the duty cycle in the PWM signal, so as to maintain the adjustment direction of the working voltage of the photovoltaic panel (that is, the disturbance direction, that is, maintain the disturbance direction of the working voltage of the photovoltaic panel in the previous cycle in this cycle), and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel in this cycle.

[0053] Among them, maintaining the adjustment direction of the working voltage of the photovoltaic panel is to control the adjustment direction of the working voltage of the photovoltaic panel in this cycle to be the same as the adjustment direction of the working voltage of the photovoltaic panel in the previous cycle. Specifically, if the adjustment direction of the working voltage of the photovoltaic panel in the previous cycle is to increase, then the adjustment direction of the working voltage of the photovoltaic panel in this cycle continues to be maintained to increase; if the adjustment direction of the working voltage of the photovoltaic panel in the previous cycle is to decrease, then the adjustment direction of the working voltage of the photovoltaic panel in this cycle continues to be maintained to decrease.

[0054] After determining the adjustment direction of maintaining the working voltage of the photovoltaic panel, the working voltage of the photovoltaic panel can be adjusted according to the adjustment direction of the working voltage of the photovoltaic panel in this cycle. Specifically, if it is determined that the adjustment direction of the working voltage of the photovoltaic panel in this cycle is to increase, the working voltage of the photovoltaic panel in this cycle is increased, and if it is determined that the adjustment direction of the working voltage of the photovoltaic panel in this cycle is to decrease, the working voltage of the photovoltaic panel in this cycle is reduced.

[0055] Among them, the increase and decrease of the working voltage of the photovoltaic panel are consistent.

[0056] S14: regulating the adjustment direction of the working voltage of the photovoltaic panel according to the output voltage change ratio and the output current change ratio, and adjusting the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel.

[0057] If the absolute value of the output voltage change ratio is not less than the first set value and / or the absolute value of the output current change ratio is not less than the second set value, that is, when any of the following three situations occurs: (1) the absolute value of the output voltage change ratio is greater than or equal to the corresponding first set value, and the absolute value of the output current change ratio is less than the corresponding second set value (that is, |K1| ≥ K 10 、|K2| <K 20 ); (2) the absolute value of the output voltage change ratio is less than the corresponding first set value, and the absolute value of the output current change ratio is greater than or equal to the corresponding second set value (i.e. |K1| <K 10 、|K2|≥K 20 ); (3) The absolute value of the output voltage change ratio is greater than or equal to the corresponding first set value, and the absolute value of the output current change ratio is greater than or equal to the corresponding second set value (i.e. |K1|≥K 10 、|K2|≥K 20 ), it means that the output voltage or output current changes are not caused by the acquisition error, but the output power changes. At this time, the adjustment direction of the working voltage of the photovoltaic panel can be regulated according to the relationship between the output voltage change ratio and the output current change ratio and the corresponding set value to obtain the adjustment direction of the working voltage of the photovoltaic panel in this cycle. Then, the working voltage of the photovoltaic panel can be adjusted according to the adjustment direction of the working voltage of the photovoltaic panel in this cycle.

[0058] S15: Determine whether it is at the maximum power point or whether the maximum power point flag is valid, determine the preset timing execution time according to the determination result, and wait until the preset timing execution time is reached. Then, return to step S11.

[0059] After executing step S13 or step S14, that is, after adjusting the working voltage of the photovoltaic panel, it can be determined whether it is at the maximum power point or whether the maximum power point flag is valid, and the preset timing execution time can be determined according to the judgment result. Starting from the end point of this cycle (that is, the preset timing execution time is determined according to the judgment result), after the time interval reaches the preset timing execution time (during which the control module collects the parameters of the output acquisition circuit), the next cycle is performed, that is, the step of determining the current output voltage and the current output current corresponding to the output voltage and the output current collected by the output acquisition circuit within the preset timing execution time can be returned, that is, the output voltage and the output current collected by the output acquisition circuit within the preset timing execution time are obtained (the specific process is: the output voltage and the output current of the voltage regulating circuit collected by the output acquisition circuit within the preset timing execution time are calculated according to the parameters of the output acquisition circuit collected within the preset timing execution time), and the actions included in one cycle such as the current output voltage and the current output current are determined according to the output voltage and the output current collected by the output acquisition circuit within the preset timing execution time to achieve maximum power point tracking.

[0060] Among them, the maximum power point flag is valid, indicating that the photovoltaic panel is within the maximum power point range (the maximum power point range is a range determined based on the maximum power point, the first set value, the second set value, etc., which includes the maximum power point, and can be specifically near the maximum power point), and the maximum power point flag is invalid, indicating that the photovoltaic panel is not within the maximum power point range. In the initial case (that is, in the first cycle), the maximum power point flag is invalid by default. In subsequent cycles, it can be determined whether the maximum power point flag should be valid / invalid according to the corresponding situation.

[0061] From the above, it can be seen that the embodiment of the present application improves the interference observation method, and the power is split into voltage and current for judgment. When the output voltage and the output current are determined to be within their respective error ranges according to the output voltage change ratio, the output current change ratio and the corresponding first set values, the adjustment direction of the working voltage of the photovoltaic panel is not changed, and the adjustment direction of the working voltage of the photovoltaic panel is maintained to avoid sampling error interference. When at least one of the output voltage and the output current is determined to be not within the corresponding error range according to the output voltage change ratio, the output current change ratio and the corresponding first set values, the adjustment direction of the working voltage of the photovoltaic panel is regulated according to the output voltage change ratio and the output current change ratio, that is, the output power of the photovoltaic panel is adjusted, and it is determined whether the photovoltaic panel is at the maximum power point or whether the maximum power point flag is valid, and a cycle is performed based on the judgment result to achieve maximum power point tracking. The embodiment of the present application improves the accuracy of the interference observation method by splitting the power into voltage and current for judgment, thereby minimizing misjudgment. In addition, the embodiment of the present application can use a low-precision acquisition circuit + a control module with ordinary performance to achieve stable and good MPPT tracking efficiency. There is no need to use an acquisition circuit with high sampling accuracy (sampling accuracy is the degree of error between the actual voltage and the collected voltage) and a control module with good performance. Therefore, the requirements for related equipment for maximum power point tracking can be reduced, and the cost of maximum power point tracking can be reduced.

[0062] The above technical solution disclosed in the embodiment of the present application determines whether the absolute value of the output voltage change ratio is less than the first set value and the absolute value of the output current change ratio is less than the second set value in each cycle. If the absolute value of the output voltage change ratio is less than the corresponding first set value and the absolute value of the output current change ratio is less than the corresponding second set value, it indicates that the changes in the output voltage and the output current are both within their respective error ranges. At this time, the adjustment direction of the working voltage of the photovoltaic panel is maintained to avoid the sampling error interfering with the maximum power point tracking. If the absolute value of the output voltage change ratio is not less than the corresponding first set value and / or the absolute value of the output current change ratio is not less than the corresponding second set value, it indicates that the change in at least one of the output voltage and the output current exceeds the error range. At this time, the output voltage change ratio and the output current change ratio can be used to indirectly determine the changes in the output power and the input power (i.e., the output power of the photovoltaic panel) of the voltage regulation circuit, so as to regulate the adjustment direction of the working voltage of the photovoltaic panel based on the power changes. Compared with the existing interference observation method for determining power, the present application improves the interference observation method by splitting the power into voltage and current, and using the voltage change ratio and the corresponding first set value, the current change ratio and the corresponding second set value for determination, so as to reduce the interference of errors and improve the determination accuracy of the interference observation method.

[0063] See also Figure 4, which shows a flow chart of another maximum power point tracking method provided by an embodiment of the present application. A maximum power point tracking method provided by an embodiment of the present application maintains the adjustment direction of the working voltage of the photovoltaic panel and adjusts the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel, which may include:

[0064] Maintaining the first duty cycle adjustment state in the previous cycle, obtaining the first duty cycle adjustment state in this cycle, obtaining the current PWM signal according to the first duty cycle adjustment state in this cycle, and adjusting the output power of the voltage regulation circuit according to the current PWM signal to adjust the working voltage of the photovoltaic panel;

[0065] Regulating the adjustment direction of the working voltage of the photovoltaic panel according to the output voltage change ratio and the output current change ratio, and adjusting the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel, may include:

[0066] According to the output voltage change ratio, the output current change ratio and the first duty cycle adjustment state in the previous cycle, the first duty cycle adjustment state in this cycle is obtained, and the current PWM signal is obtained according to the first duty cycle adjustment state in this cycle. According to the current PWM signal, the output power of the voltage regulation circuit is adjusted to adjust the working voltage of the photovoltaic panel;

[0067] The first duty cycle adjustment state includes increasing and decreasing.

[0068] In an embodiment of the present application, the control module can first determine whether the absolute value of the output voltage change ratio is less than the first set value and the absolute value of the output current change ratio is less than the second set value, and obtain the first duty cycle adjustment state in this cycle based on the judgment result and the first duty cycle adjustment state in the previous cycle (that is, the current duty cycle adjustment state), obtain the current PWM signal (that is, the PWM signal of this cycle) based on the first duty cycle adjustment state in this cycle, and adjust the output power of the voltage regulation circuit based on the current PWM signal. Accordingly, the input power of the voltage regulation circuit will also change, that is, the output power of the photovoltaic panel will change, thereby changing the operating voltage of the photovoltaic panel.

[0069] Specifically, the adjustment direction of the working voltage of the photovoltaic panel is maintained, and the implementation method of adjusting the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel can be specifically: maintaining the first duty cycle adjustment state in the last cycle, obtaining the first duty cycle adjustment state in this cycle, that is, the first duty cycle adjustment state in this cycle can be controlled to be the same as the first duty cycle adjustment state in the last cycle, wherein the first duty cycle adjustment state includes increasing and decreasing. Specifically, if the first duty cycle adjustment state in the last cycle is increasing, the first duty cycle adjustment state in this cycle continues to maintain increasing, and if the first duty cycle adjustment state in the last cycle is decreasing, the first duty cycle adjustment state in this cycle continues to maintain decreasing. Among them, the amplitude of the increase and decrease of the duty cycle is consistent (that is, the duty cycle increment value and the duty cycle decrement value can be the same). It can be assumed that in the initial state, the first duty cycle adjustment state is increasing. At this time, the initial duty cycle can be set to the minimum value, and the minimum value is not 0, so as to avoid the inability to start the cycle process due to no current. After maintaining the first duty cycle adjustment state in the previous cycle, the first duty cycle adjustment state in this cycle can be obtained, and then the current PWM signal can be obtained according to the first duty cycle adjustment state in this cycle. Among them, if the first duty cycle adjustment state is increasing, the PWM duty cycle (that is, the duty cycle in the PWM signal) increases, and the current PWM signal is obtained. If the first duty cycle adjustment state is decreasing, the PWM duty cycle decreases, and the current PWM signal is obtained. The increase or decrease of the PWM duty cycle will affect the output power. After obtaining the current PWM signal, the current PWM signal can be output to the voltage regulation circuit, as shown in the following example. Figure 2 As shown, the microcontroller unit in the control module can output the obtained PWM signal to the drive circuit, which enhances the PWM signal and then outputs it to the voltage regulation circuit to adjust the output power of the voltage regulation circuit, thereby achieving the adjustment of the working voltage of the photovoltaic panel.

[0070] The adjustment direction of the working voltage of the photovoltaic panel is regulated according to the output voltage change ratio and the output current change ratio, and the working voltage of the photovoltaic panel is adjusted according to the adjustment direction of the working voltage of the photovoltaic panel. Specifically, the first duty cycle adjustment state in this cycle is obtained according to the output voltage change ratio, the output current change ratio and the first duty cycle adjustment state in the previous cycle, and then the PWM signal of this cycle is obtained according to the first duty cycle adjustment state in this cycle, and then the PWM signal of this cycle is output to the voltage regulation circuit, as shown in the following example. Figure 2 As shown, the microcontroller unit in the control module can output the obtained PWM signal to the drive circuit, and the drive circuit enhances the PWM signal and outputs it to the voltage regulation circuit to adjust the output power of the voltage regulation circuit, thereby achieving the adjustment of the working voltage of the photovoltaic panel.

[0071] It should be noted that in the above process, the control module can adjust the two complementary PWM signals through the first duty cycle adjustment state (the two complementary PWM signals can be divided into a main PWM signal and a sub-PWM signal. The first duty cycle adjustment state mentioned in this application is increasing or decreasing, which refers to the duty cycle adjustment state in the main PWM signal, that is, the control module can be applied to the application scenario of two complementary PWM). Of course, the control module can also adjust a single PWM signal through the first duty cycle adjustment state (that is, the control module can also be applied to the application scenario of a single PWM). After obtaining the current PWM signal, the output power of the voltage regulation circuit will be adjusted according to the duty cycle in the current PWM signal. The corresponding output voltage and output current will change, and the input power of the corresponding voltage regulation circuit will also change, that is, the output power of the photovoltaic panel will change according to the duty cycle in the current PWM signal. Figure 1 It can be seen from the IV curve of the photovoltaic panel shown that when the output power of the photovoltaic panel changes, its operating voltage and operating current will also change accordingly. Taking the voltage regulation circuit as a BUCK DCDC buck circuit or a BOOST DCDC boost circuit as an example, after the control module adjusts the duty cycle, the output power of the BUCK DCDC buck circuit or the BOOST DCDC boost circuit will change, and accordingly, the input power of the BUCK DCDC buck circuit or the BOOST DCDC boost circuit will also change, that is, the output power of the photovoltaic panel changes. According to the IV curve of the photovoltaic panel, the output power of the photovoltaic panel changes, and the output voltage and output current of the photovoltaic panel will also change accordingly.

[0072] A maximum power point tracking method provided by an embodiment of the present application, obtaining a first duty cycle adjustment state in this cycle according to an output voltage change ratio, an output current change ratio, and an adjustment state of a first duty cycle in a previous cycle, may include:

[0073] Determine whether the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio;

[0074] If yes, the adjustment state of the first duty cycle in the previous cycle is maintained to obtain the adjustment state of the first duty cycle in this cycle;

[0075] If not, when the first duty cycle adjustment state in the previous cycle is increasing, the first duty cycle adjustment state in this cycle is decreasing, and when the first duty cycle adjustment state in the previous cycle is decreasing, the first duty cycle adjustment state in this cycle is increasing.

[0076] According to P=U×I, the power at the previous moment is set to P1=U1×I1, and the power at the next moment is P2=U2×I2. The power between U2 and U1 can be expressed by the mathematical relationship U2=(1+K1)×U1. Similarly, I2=(1+K2)×I1, then P2=U2×I2=(1+K1)×U1×(1+K2)×I1=U1×I1+U1×I1×K2+U1×I1×K1+U1×I1×K1×K2=P1+P1×K2+P1×K1+P1×K1×K2. At this time, the power change ratio is (P2-P1) / P1=K2+K1+K1×K2. Then, as long as K2+K1+K1×K2≥0, it means that the output power increases or remains unchanged, that is, K2+K1≥-K1×K2.

[0077] Therefore, in the embodiment of the present application, when the first duty cycle adjustment state in the previous cycle is controlled according to the output voltage change ratio and the output current change ratio, it can be specifically determined whether the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio, that is, it can be determined whether K1+K2 is greater than or equal to -K1×K2.

[0078] If K1+K2≥-K1×K2, it indicates that the output power increases or remains unchanged. At this time, the first duty cycle adjustment state in the previous cycle can be maintained, that is, the first duty cycle adjustment state in this cycle can be controlled to be the same as the first duty cycle adjustment state in the previous cycle. Specifically, if the first duty cycle adjustment state in the previous cycle is increasing, the first duty cycle adjustment state in this cycle continues to increase, and if the first duty cycle adjustment state in the previous cycle is decreasing, the first duty cycle adjustment state in this cycle continues to decrease.

[0079] If K1+K2<-K1×K2, it indicates that the output power becomes smaller. At this time, if the first duty cycle adjustment state in the previous cycle is increasing, the first duty cycle adjustment state in this cycle is controlled to be decreasing, so as to obtain the first duty cycle adjustment state in this cycle; if the first duty cycle adjustment state in the previous cycle is decreasing, the first duty cycle adjustment state in this cycle is controlled to be increasing, so as to obtain the first duty cycle adjustment state in this cycle. That is, when K1+K2<-K1×K2, the first duty cycle adjustment state in the previous cycle can be modified to obtain the first duty cycle adjustment state in this cycle, that is, the first duty cycle adjustment state in this cycle is controlled to be opposite to the first duty cycle adjustment state in the previous cycle, that is, the first duty cycle adjustment state in this cycle is changed. Among them, the amplitudes of increasing and decreasing can be consistent.

[0080] Of course, it is also possible to determine whether the sum of the product of the output voltage change ratio and the output current change ratio, the output voltage change ratio and the output current change ratio is greater than or equal to 0, that is, to determine whether K2+K1+K1×K2 is greater than or equal to 0. If the sum of the above three items is greater than or equal to 0, the first duty cycle adjustment state in the previous cycle is maintained; if the sum of the above three items is less than 0, when the first duty cycle adjustment state in the previous cycle is increasing, the first duty cycle adjustment state in this cycle is decreasing, and when the first duty cycle adjustment state in the previous cycle is decreasing, the first duty cycle adjustment state in this cycle is increasing.

[0081] That is, the adjustment direction of the working voltage of the photovoltaic panel is regulated according to the output voltage change ratio and the output current change ratio, which can be specifically: judging whether the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio, that is, judging whether K1+K2 is greater than or equal to -K1×K2. If K1+K2≥-K1×K2, it indicates that the output power increases or remains unchanged. At this time, the adjustment direction of the working voltage of the photovoltaic panel can be maintained, that is, the adjustment direction of the working voltage of the photovoltaic panel in this cycle can be controlled to be the same as the adjustment direction of the working voltage of the photovoltaic panel in the previous cycle. Specifically, if the adjustment direction of the working voltage of the photovoltaic panel in the previous cycle is to increase, the adjustment direction of the working voltage of the photovoltaic panel in this cycle continues to increase, and if the adjustment direction of the working voltage of the photovoltaic panel in the previous cycle is to decrease, the adjustment direction of the working voltage of the photovoltaic panel in this cycle continues to decrease. If K1+K2<-K1×K2, it indicates that the output power decreases. At this time, the adjustment direction of the working voltage of the photovoltaic panel is changed, that is, the adjustment direction of the working voltage of the photovoltaic panel in this cycle is controlled to be opposite to the adjustment direction of the working voltage of the photovoltaic panel in the previous cycle. Specifically, if the adjustment direction of the working voltage of the photovoltaic panel in the previous cycle is to increase, then the adjustment direction of the working voltage of the photovoltaic panel in this cycle is to decrease; if the adjustment direction of the working voltage of the photovoltaic panel in the previous cycle is to decrease, then the adjustment direction of the working voltage of the photovoltaic panel in this cycle is to increase. Of course, it is also possible to determine whether the product of the output voltage change ratio and the output current change ratio, the sum of the output voltage change ratio and the output current change ratio is greater than or equal to 0, and adjust the adjustment direction of the working voltage of the photovoltaic panel according to the corresponding judgment result.

[0082] The above embodiment can realize two judgments on voltage and current: one judgment is to judge whether the absolute value of the output voltage change ratio is less than the corresponding first set value and whether the absolute value of the output current change ratio is less than the corresponding second set value. If so, it is determined that the output voltage and the output current are within their respective error ranges, and the first duty cycle adjustment state is not changed (that is, the adjustment direction of the working voltage of the photovoltaic panel is not changed) to avoid error interference. Otherwise, a second judgment is performed; the second judgment is to judge whether the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio, so as to indirectly judge the change of output power through the relationship between the output voltage change ratio and the output current change ratio, so as to adjust the adjustment state of the duty cycle according to the change, so as to adjust the output power of the voltage regulation circuit, so as to adjust the output power of the photovoltaic panel, so as to improve the determination accuracy of the interference observation method and improve the MPPT effect.

[0083] A maximum power point tracking method provided by an embodiment of the present application, which obtains a current PWM signal according to a first duty cycle adjustment state in this cycle, may include:

[0084] If the first duty cycle adjustment state in this cycle is increasing, it is determined whether the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle; if the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle, it is determined that the duty cycle in the current PWM signal is equal to the maximum duty cycle; if the sum of the current duty cycle and the duty cycle adjustment value is not greater than the maximum duty cycle, it is determined that the duty cycle in the current PWM signal is equal to the sum of the current duty cycle and the duty cycle adjustment value;

[0085] If the first duty cycle adjustment state in this cycle is decreasing, determine whether the difference between the current duty cycle and the duty cycle adjustment value is less than the minimum duty cycle value; if the difference between the current duty cycle and the duty cycle adjustment value is less than the minimum duty cycle value, determine that the duty cycle in this PWM signal is equal to the minimum duty cycle value; if the difference between the current duty cycle and the duty cycle adjustment value is not less than the minimum duty cycle value, determine that the duty cycle in this PWM signal is equal to the difference between the current duty cycle and the duty cycle adjustment value.

[0086] In the embodiment of the present application, a maximum duty cycle value (the maximum value is not 100%), a minimum duty cycle value (the minimum value is not 0%) and a duty cycle adjustment value (the value is greater than 0%) can be preset. The specific process of obtaining the current PWM signal according to the first duty cycle adjustment state in this cycle can be:

[0087] (a) If the adjustment state of the first duty cycle in this cycle is increasing, it can be determined whether the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle. The current duty cycle is the duty cycle in the PWM signal obtained after the last cycle.

[0088] If it is determined that the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle value, then it is determined that the duty cycle in the current PWM signal is equal to the maximum duty cycle value.

[0089] If it is determined that the sum of the current duty cycle and the duty cycle adjustment value is not greater than the maximum duty cycle value, then it is determined that the duty cycle in the current PWM signal is equal to the sum of the current duty cycle and the duty cycle adjustment value.

[0090] Through the above process, the duty cycle in the current PWM signal is not greater than the maximum duty cycle.

[0091] (b) If the first duty cycle adjustment state in this cycle is decreasing, it can be determined whether the difference between the current duty cycle and the duty cycle adjustment value is less than the minimum duty cycle value, that is, whether (current duty cycle - duty cycle adjustment value) is less than the minimum duty cycle value.

[0092] If it is determined that the difference between the current duty cycle and the duty cycle adjustment value is smaller than the minimum duty cycle value, then it is determined that the duty cycle in the current PWM signal is equal to the minimum duty cycle value.

[0093] If it is determined that the difference between the current duty cycle and the duty cycle adjustment value is not less than the minimum duty cycle value, then the duty cycle in the current PWM signal is determined to be equal to the difference between the current duty cycle and the duty cycle adjustment value.

[0094] Through the above process, the duty cycle in the current PWM signal is not less than the minimum duty cycle value.

[0095] Through the above process, the duty cycle in the current PWM signal is within the range determined by the minimum duty cycle and the maximum duty cycle, thereby preventing the duty cycle in the PWM signal from being too large or too small and improving the maximum power point tracking effect.

[0096] The maximum power point tracking method provided in the embodiment of the present application determines whether the maximum power point is reached or whether the maximum power point flag is valid, and determines a preset timing execution time according to the determination result, which may include:

[0097] Determine whether the maximum power point flag is valid;

[0098] If the maximum power point flag is invalid, determine whether it is at the maximum power point; if it is not at the maximum power point, determine the preset timing execution time as the first timing execution time; if it is at the maximum power point, mark the maximum power point flag as valid, and determine the preset timing execution time as the second timing execution time;

[0099] If the maximum power point flag is valid, determining the preset timing execution time as the second timing execution time;

[0100] The second scheduled execution time is greater than the first scheduled execution time.

[0101] In the embodiment of the present application, when determining whether the device is at the maximum power point or whether the maximum power point flag is valid, and determining the preset timing execution time according to the determination result, it is specifically possible to first determine whether the maximum power point flag is valid.

[0102] If it is determined that the maximum power point flag is invalid, it can be determined whether it is at the maximum power point.

[0103] If it is determined that it is not at the maximum power point, the preset timing execution time can be determined as the first timing execution time, that is, the cycle can be executed regularly according to the first timing execution time. Specifically, when it is determined that the maximum power point flag is invalid and it is not at the maximum power point, it can start from the determination of the current output voltage and the current output current of this cycle, and after the time interval reaches the first timing execution time, the next cycle is performed, and the next cycle starts from determining a new round of output voltage and output current.

[0104] If it is determined to be at the maximum power point, the maximum power point flag can be marked as valid, wherein the maximum power point flag is valid, indicating that it is within the maximum power point range (the maximum power point range is based on the maximum power point, the first set value-the fourth set value, etc., the range includes the maximum power point, specifically, it can be near the maximum power point), and the maximum power point flag is invalid, indicating that it is not within the maximum power point range. In addition, the preset timing execution time can be determined as the second timing execution time, that is, the cycle can be executed according to the second timing execution time, wherein the second timing execution time is greater than the first timing execution time, and the size of the first timing execution time and the second timing execution time can be determined by relevant personnel based on experience or through experiments, for example: the first timing execution time can be 40ms, and the second timing execution time can be 80ms, that is, after reaching the maximum power point, the timing execution time is lengthened, because the purpose is to stabilize at the maximum power point, and if the timing time is increased, the frequent back and forth oscillation near the maximum power point can be reduced. Specifically, when it is determined to be at the maximum power point and the maximum power point flag is valid, the current output voltage and current can be determined starting from this cycle, and the next cycle can be performed after the time interval reaches the second timing execution time.

[0105] If, when judging whether the maximum power point flag is valid, it is determined that the maximum power point flag is valid, the preset timing execution time can be determined as the second timing execution time, that is, the output voltage and the output current of this cycle can be determined starting from this cycle, and the next cycle can be performed after the time interval reaches the second timing execution time.

[0106] Compared with the existing interference observation method, frequent oscillations will occur when tracking the maximum power point (specifically, since the existing interference observation method needs to increase or decrease the working voltage of the photovoltaic panel before determining the power change, and the existing interference observation method does not mark the maximum power point, even if the maximum power point is reached, frequent disturbance judgments will be required, resulting in oscillations, that is, frequent back and forth jittering near the maximum power point), causing energy loss, the embodiment of the present application improves the frequent disturbances of the interference observation method at the maximum power point position by increasing the preset timing execution time, thereby suppressing frequent oscillations, reducing energy loss, and improving energy utilization.

[0107] The embodiments of the present application achieve rapid disturbance by determining a relatively small preset timing execution time when the maximum power point flag is invalid and not at the maximum power point, so as to quickly and efficiently determine the position of the maximum power point, and determine a relatively large preset timing execution time when at the maximum power point or when the maximum power point flag is valid to minimize misjudgment and reduce frequent oscillations when tracking the maximum power point, so as to reduce energy loss and improve energy utilization of photovoltaic panels.

[0108] A maximum power point tracking method provided by an embodiment of the present application may further include, if it is determined that the maximum power point flag is valid, before determining that the preset timing execution time is the second timing execution time:

[0109] Determine whether the maximum power point flag should be invalid;

[0110] If yes, the maximum power point flag is updated to invalid, and the preset timing execution time is determined to be the first timing execution time;

[0111] If not, the step of determining the preset scheduled execution time as the second scheduled execution time is executed.

[0112] In the embodiment of the present application, if it is determined that the maximum power point flag is valid, before determining that the preset timing execution time is the second timing execution time, it can also be determined whether the maximum power point flag should be invalid.

[0113] If it is determined that the maximum power point flag should be invalid, the maximum power point flag can be updated to invalid (that is, indicating that it is not within the maximum power point range after the next cycle adjustment), and the preset timing execution time is determined to be the first timing execution time, that is, the preset timing execution time is restored to normal, so as to quickly and efficiently track and determine the maximum power point again.

[0114] If it is determined that the maximum power point flag should not be invalid, the maximum power point flag can be kept valid and the preset timing execution time can be determined as the second timing execution time, and the cycle is performed with a relatively large preset timing execution time, thereby minimizing misjudgment and frequent oscillations when tracking the maximum power point.

[0115] The above process can not only improve the frequent disturbance of the maximum power point position in the interference observation method, but also will not affect the dynamic response effect. Among them, dynamic response refers to the process that the maximum power point needs to be re-tracked and the MPPT process needs to be completed again when the sun becomes weaker or stronger and the energy of the photovoltaic panel changes.

[0116] A maximum power point tracking method provided by an embodiment of the present application, wherein the control module is also connected to an input acquisition circuit, and the input acquisition circuit is connected between the photovoltaic panel and the voltage regulation circuit. Before determining whether the maximum power point flag should be invalid, the method may further include:

[0117] Determine the current input voltage and current according to the input voltage and input current collected by the input collection circuit within the preset timing execution time, determine the input voltage change ratio according to the current input voltage and the previous input voltage, and determine the input current change ratio according to the current input current and the previous input current;

[0118] Determining whether the maximum power point flag should be invalid may include:

[0119] Determine whether the absolute value of the input voltage change ratio is not less than the third set value or the absolute value of the input current change ratio is not less than the fourth set value, or whether it occurs N1 times in succession: the absolute value of the output voltage change ratio is not less than the first set value, the absolute value of the output current change ratio is not less than the second set value, and the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio; N1 is an integer greater than 0;

[0120] If so, it is determined that the maximum power point flag should be invalid;

[0121] If not, it is determined that the maximum power point flag should not be invalid.

[0122] In the embodiment of the present application, an input acquisition circuit can also be provided between the photovoltaic panel and the voltage regulating circuit, and the input acquisition circuit is connected to the control module. The input acquisition circuit can be specifically an input voltage and current acquisition circuit, which is used to acquire the input voltage and input current of the voltage regulating circuit (that is, the output voltage and output current of the photovoltaic panel, and the input acquisition circuit can specifically acquire the input voltage and input current of the voltage regulating circuit in real time), and scale the acquired input voltage based on a preset second voltage scaling ratio to obtain a second scaled voltage, and scale the acquired input current based on a preset second current scaling ratio to obtain a second scaled current, and the control module can obtain the second scaled voltage and second scaled current from the input acquisition circuit on a regular basis or in real time. Among them, the second scaled voltage ratio and the second current scaled ratio can be specifically set accordingly according to the voltage range, current range, etc. that the control module can withstand when designing the input acquisition circuit. The input acquisition circuit scales the collected input voltage and input current in order to make the voltage and current obtained by the control module from the input acquisition circuit within the tolerance range of the control module, so as to avoid permanent damage to the control module (that is, using the input acquisition circuit to convert the actual voltage and current values ​​into data that the control module can accept and recognize). After the control module collects the second scaled voltage and the second scaled current at the input acquisition circuit, it can numerically restore the second scaled voltage and the second scaled current to obtain the input voltage and input current collected by the input acquisition circuit. Specifically, the control module uses the inverse of the second voltage scaling ratio to restore the second scaled voltage to obtain the input voltage collected by the input acquisition circuit, and uses the inverse of the second current scaling ratio to restore the second scaled current to obtain the input current collected by the input acquisition circuit. Among them, the control module can simultaneously collect the parameters of the input acquisition circuit and the parameters of the output acquisition circuit in real time or periodically, calculate the input voltage and input current collected by the input acquisition circuit according to the collected parameters of the input acquisition circuit, and calculate the output voltage and output current collected by the output acquisition circuit according to the collected parameters of the output acquisition circuit.

[0123] The control module can collect the parameters of the input acquisition circuit within the preset timing execution time (the parameters here are the second scaling voltage and the second scaling current mentioned above), and calculate the input voltage and input voltage of the voltage regulating circuit collected by the input acquisition circuit within the preset timing execution time based on the parameters of the input acquisition circuit collected within the preset timing execution time. That is, the control module can collect the parameters of the input acquisition circuit, and can record the data collected each time, and can determine whether the timing execution time reaches the preset timing execution time. If the timing execution time does not reach the preset timing execution time, it returns to the step of collecting the parameters of the input acquisition circuit. If the timing execution time reaches the preset timing execution time, the input voltage and input current collected by the input acquisition circuit within the preset timing execution time can be calculated based on the parameters of the input acquisition circuit collected within the preset timing execution time. Then, the median average filtering algorithm and other algorithms are used to pre-process and calculate all the input voltage and input current data collected by the input acquisition circuit within the preset timing execution time to obtain the corresponding input voltage and input current. Then, all the data stored in the cycle can be cleared to reduce the occupation of storage space and facilitate preparation for the next cycle to obtain and process data. It should be noted that the above process can be carried out together with the process of obtaining the data collected by the output acquisition circuit and calculating the output voltage and output current collected by the output acquisition circuit based on the data. On this basis, if the control module determines whether the output current is equal to 0, if it is determined that the output current is equal to 0, it can return to the step of collecting the parameters of the output acquisition circuit and the parameters of the input acquisition circuit within the preset timing execution time, calculating the output voltage and output current collected by the output acquisition circuit within the preset timing execution time according to the parameters of the output acquisition circuit collected within the preset timing execution time, and calculating the input voltage and input current collected by the input acquisition circuit within the preset timing execution time according to the parameters of the input acquisition circuit collected within the preset timing execution time. If it is determined that the output current is not equal to 0, the subsequent operation can be performed.

[0124] Starting from the second cycle, if it is determined that the output current is not equal to 0, after determining the input voltage and the input current, the input voltage can be compared with the last input voltage, and the input voltage change ratio K3 can be obtained by using K3=(this input voltage-last input voltage) / last input voltage. In addition, the input current can be compared with the last input current, and the input current change ratio K4 can be obtained by using K4=(this input current-last input current) / last input current.

[0125] On the basis of the above, it is determined whether the maximum power point flag should be invalid, specifically, it can be determined whether |K3| is not less than its corresponding third set value K 30Or whether |K4| is not less than its corresponding fourth setting value K 40 , or, determine whether it appears N1 times in a row (specifically, it may appear at least N1 times in a row): |K1|≥K 10 and / or |K2|≥K 20 , and K1+K2≥-K1×K2, so as to judge whether the maximum power point is likely to change through this process. If there is a possibility of change, the maximum power point flag is invalid and the tracking is restarted. Among them, the third setting value K 30 and the fourth setting value K 40 The size of can be determined by relevant personnel according to the working characteristics of the photovoltaic panel and the collection error of the input collection circuit. For example, the third setting value K 30 and the fourth setting value K 40 N1 is a first preset value, which is an integer greater than 0, specifically, it can be an integer greater than 1, and the specific value can be set by relevant personnel according to experience, for example, it can be 3, so as to improve the accuracy of the maximum power point change determination.

[0126] If |K3|≥K 30 Or |K4|≥K 40 , it means that the input has changed. At this time, it can be basically determined that the photovoltaic energy has changed and the maximum power point has changed (that is, the light has changed and the maximum power point of the photovoltaic panel has changed). At this time, the preset timing execution time can be restored to normal to cope with the change in photovoltaic energy, so that the tracking point can be adjusted quickly. If it occurs N1 times in a row: |K1|≥K 10 and / or |K2|≥K 20 And K1+K2≥-K1×K2, it is also considered that the maximum power point may change. At this time, the preset timing execution time returns to normal and the maximum power point is readjusted.

[0127] That is, in the above judgment, if |K3|≥K 30 Or |K4|≥K 40 , or N1 times in a row |K1|≥K 10 、|K2|≥K 20 If at least one item in and K1+K2≥-K1×K2 is met, it can be determined that the maximum power point may change. At this time, the maximum power point flag can be invalidated to re-track and ensure the final accuracy.

[0128] If |K3| <K 30 And |K4| <K 40 , and it does not appear N1 times consecutively |K1|≥K 10 、|K2|≥K 20If at least one item in and K1+K2≥-K1×K2 is found, it is determined that the maximum power point flag should not be invalidated.

[0129] Through the above method, it is possible to judge whether the maximum power point is likely to change, and if there is a possibility of change, the maximum power point flag is invalidated to immediately re-track, thereby ensuring the efficiency and immediacy of tracking, thereby improving the accuracy of maximum power point tracking, thereby improving the utilization rate of the electricity generated by the photovoltaic panels and reducing the loss of electricity generated by the photovoltaic panels.

[0130] A maximum power point tracking method provided in an embodiment of the present application may include: determining the current input voltage and the current input current according to the input voltage and the input current collected by the input collection circuit within a preset timing execution time;

[0131] The input voltage and input current collected by the input collection circuit within the preset timing execution time are preprocessed, and the current input voltage is determined according to the preprocessed input voltage, and the current input current is determined according to the preprocessed input current.

[0132] In an embodiment of the present application, when determining the current input voltage and current input according to the input voltage and input current collected by the input collection circuit within the preset timing execution time, first, the input voltage and input current collected by the input collection circuit within the preset timing execution time can be preprocessed (for example, removing abnormal values, etc.), and then the current input voltage is determined according to the preprocessed input voltage, and the current input current is determined according to the preprocessed input current. Specifically, the median average filtering algorithm can be used to process the input voltage and input current collected by the input collection circuit within the preset timing execution time, and the current input voltage and current input current are obtained accordingly. Among them, the median average filtering algorithm is to obtain the collected data in the collection cycle, remove the maximum and minimum values ​​in the collected data, and calculate the average value of the remaining data. Of course, the average filtering algorithm can also be used to process the input voltage and input current collected by the input collection circuit within the preset timing execution time, and the current input voltage and current input current are obtained accordingly.

[0133] The above method can improve the quality of determining the current input voltage and the current input current, so as to improve the accuracy of maximum power point tracking and the determination accuracy of the interference observation method.

[0134] A maximum power point tracking method provided by an embodiment of the present application may further include: after determining an input voltage change ratio according to a current input voltage and a previous input voltage, and determining an input current change ratio according to a current input current and a previous input current:

[0135] If the absolute value of the input voltage change ratio is not less than the fifth set value, the last input voltage is updated using the current input voltage; if the absolute value of the input voltage change ratio is less than the fifth set value, the last input voltage is maintained;

[0136] If the absolute value of the input current change ratio is not less than the sixth set value, the last input current is updated with the current input current; if the absolute value of the input current change ratio is less than the sixth set value, the last input current is maintained.

[0137] In the embodiment of the present application, after determining the input voltage change ratio K3 according to the current input voltage and the previous input voltage, and determining the input current change ratio K4 according to the current input current and the previous input current, it can be determined whether |K3| is not less than the fifth set value K 50 , where K 50 The size of can be determined by relevant personnel based on the voltage acquisition error of the input acquisition circuit, for example, it can be 0.5%. 50 , it indicates that the change in input voltage is caused by the change in output power. At this time, the last input voltage can be updated using the current input voltage, that is, the last input voltage = the current input voltage. If |K3| <K 50 , the input voltage may change due to the acquisition error of the input acquisition circuit, or it may change due to the output power change. At this time, the last input voltage can be maintained and the current input voltage is not saved, that is, the input voltage change ratio is determined by using the last input voltage maintained before in the next cycle, so that if the output power changes and the input voltage changes, the real effective value is superimposed, so that the absolute value of the input voltage change ratio can exceed the fifth set value when the subsequent input voltage change ratio is calculated and determined (if the acquisition error causes the input voltage to change, the error will only be superimposed on the current value), thereby improving the accuracy of the interference observation method.

[0138] Similar to the above process, it can also be determined whether |K4| is not less than the sixth set value K 60 , where K 60 The size of can be determined by relevant personnel based on the current acquisition error of the input acquisition circuit, for example, it can be 0.5%. 60 , it indicates that the change in input current is caused by the change in output power. At this time, the last input current can be updated using the current input current, that is, the last input current = the current input current. If |K4| <K 60, it may be that the input current changes due to the acquisition error of the input acquisition circuit, or it may be that the input current changes due to the change in output power. At this time, the last input current can be maintained and the current input current is not saved, that is, the input current change ratio is determined by using the last input current maintained before in the next cycle, so that if the input current changes due to the output power change, the true effective value is superimposed, so that when the subsequent input current change ratio is calculated and determined, the absolute value of the input current change ratio can exceed the sixth set value, thereby improving the determination accuracy of the interference observation method.

[0139] It should be noted that in the first cycle, the current input voltage and current input current need to be used to assign values ​​to the last input voltage and last input current, that is, in the second cycle, the last input voltage and last input current used to calculate the input voltage change ratio K3 and the input current change ratio K4 are the input voltage and input current obtained in the first cycle. Starting from the second cycle, the last input voltage and last input current can be determined according to the above-mentioned method.

[0140] A maximum power point tracking method provided by an embodiment of the present application, if it is determined that the sum of the output voltage change ratio and the output current change ratio is less than the inverse of the product of the output voltage change ratio and the output current change ratio, before obtaining the first duty cycle adjustment state in this cycle, further includes:

[0141] Assigning the second duty cycle adjustment state to the third duty cycle adjustment state, and assigning the first duty cycle adjustment state to the second duty cycle adjustment state;

[0142] Determining whether it is at the maximum power point may include:

[0143] determining whether the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and whether the third duty cycle adjustment state is equal to the first duty cycle adjustment state;

[0144] If yes, then control n to add 1, and determine whether n is greater than or equal to N2, if n is greater than or equal to N2, it is determined to be at the maximum power point, if n is less than N2, control n to be equal to 0 and determine not to be at the maximum power point; n is the number of times that the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and the third duty cycle adjustment state is equal to the first duty cycle adjustment state, and N2 is an integer greater than 0;

[0145] If not, n is controlled to be equal to 0 and it is determined that the maximum power point is not reached.

[0146] In an embodiment of the present application, if it is determined that the sum of the output voltage change ratio and the output current change ratio is less than the opposite of the product of the output voltage change ratio and the output current change ratio, before obtaining the first duty cycle adjustment state in this cycle, that is, before modifying the first duty cycle adjustment state in the previous cycle, that is, before changing the first duty cycle adjustment state, the second duty cycle adjustment state can be assigned to the third duty cycle adjustment state, the first duty cycle adjustment state can be assigned to the second duty cycle adjustment state, and the first duty cycle adjustment state, the second duty cycle adjustment state, and the third duty cycle adjustment state are used to save the state information before the change of the adjacent three duty cycle adjustment states, so as to facilitate determining whether the photovoltaic panel is at the maximum power point based on the saved information. Among them, if at least N2 (N2 is an integer greater than 0) consecutive occurrences: the third duty cycle adjustment state is equal to the first duty cycle adjustment state and the second duty cycle adjustment state is not equal to the third duty cycle adjustment state, it is determined that the photovoltaic panel is at the maximum power point, that is, if at least N2 occurrences: the third duty cycle adjustment state is increasing, the second duty cycle adjustment state is decreasing, and the first duty cycle adjustment state is increasing, or if at least N2 occurrences: the third duty cycle adjustment state is decreasing, the second duty cycle adjustment state is increasing, and the first duty cycle adjustment state is decreasing, it can be determined that the photovoltaic panel is at the maximum power point, otherwise it can be determined that the photovoltaic panel is not at the maximum power point.

[0147] If it is determined that the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and the third duty cycle adjustment state is equal to the first duty cycle adjustment state, then n can be controlled to be incremented by 1, where n represents the number of consecutive occurrences of the second duty cycle adjustment state not being equal to the third duty cycle adjustment state and the third duty cycle adjustment state being equal to the first duty cycle adjustment state. Then, it can be determined whether n is greater than or equal to N2. N2 is the second preset value, which is an integer greater than 0 (its specific size can be set by relevant personnel according to needs, etc.). The larger N2 is, the more accurate the determination of the maximum power point is, but the corresponding situation is that it is easily affected by factors such as light changes and it becomes difficult to determine the maximum power point. In practical applications, N2 is generally set to about 2 - 4. If n ≥ N2, it is determined that it is at the maximum power point, and the maximum power point flag bit is marked as valid. Then, n is controlled to be equal to 0 to facilitate the subsequent determination of the maximum power point. If n < N2, n is controlled to be equal to 0 and it is determined that it is not at the maximum power point.

[0148] If it is determined that the condition: the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and the third duty cycle adjustment state is equal to the first duty cycle adjustment state is not satisfied, then n is controlled to be equal to 0, and it is determined that it is not at the maximum power point.

[0149] Through the above method, it can be accurately determined whether it is at the maximum power point, so as to improve the determination accuracy of the perturbation observation method and minimize misjudgment to the greatest extent.

[0150] Of course, it is also possible to determine whether the device is at the maximum power point by checking whether the duty cycle adjustment status in the adjacent four cycles meets the target status. Specifically, the following method can be combined Figure 1 to determine whether the device is at the maximum power point Figure 1 Midpoint 1 is the maximum power point, point 2 is on the left side of point 1, and point 3 is on the right side of point 1. When the first duty cycle adjustment status changes, it is possible to determine whether the first duty cycle adjustment status in the adjacent four cycles meets the target status. The target status is that the first duty cycle adjustment status in the (m - 3)-th cycle is the same as that in the m-th cycle, the first duty cycle adjustment status in the (m - 2)-th cycle is the same as that in the (m - 1)-th cycle, and the first duty cycle adjustment status in the (m - 3)-th cycle is opposite to that in the (m - 2)-th cycle. The m-th cycle is the current cycle. Taking Figure 1 midpoint 1, point 2, and point 3 as an example, assume that the first duty cycle adjustment status in the (m - 3)-th cycle is increasing and adjusts from point 1 to point 2; then through the above process, it can be known that the first duty cycle adjustment status in the (m - 2)-th cycle is decreasing and adjusts from point 2 to point 1, the first duty cycle adjustment status in the (m - 1)-th cycle is decreasing and adjusts from point 1 to point 3, and the first duty cycle adjustment status in the m-th cycle is increasing and adjusts from point 3 to point 1. If it is determined that the first duty cycle adjustment status in the adjacent four cycles meets the target status, then n can be incremented by 1. At this time, n represents the number of times that the first duty cycle adjustment status in the adjacent four cycles continuously meets the target status. Then, it can be determined whether n is greater than or equal to N2. If n ≥ N2, it is determined that the device is at the maximum power point, and the maximum power point flag is marked as valid. Then, n is set to 0 for subsequent determination of the maximum power point. If n < N2, then n is set to 0 and it is determined that the device is not at the maximum power point. If it is determined that the duty cycle adjustment status in the adjacent four cycles does not meet the target status, then n is set to 0 and it is determined that the device is not at the maximum power point.

[0151] A maximum power point tracking method provided by an embodiment of the present application, which can respectively determine the current output voltage and the current output current according to the output voltage and the output current collected by an output acquisition circuit within a preset timing execution time, may include:

[0152] Preprocess the output voltage and the output current collected by the output acquisition circuit within the preset timing execution time, and determine the current output voltage according to the preprocessed output voltage, and determine the current output current according to the preprocessed output current.

[0153] In an embodiment of the present application, when determining the current output voltage and the current output current according to the output voltage and the output current collected by the output collection circuit within the preset timing execution time, first, the output voltage and the output current collected by the output collection circuit within the preset timing execution time can be preprocessed (for example, removing abnormal values, etc.), and then, the current output voltage is determined according to the preprocessed output voltage, and the current output current is determined according to the preprocessed output current, so as to improve the quality of determining the current input voltage and the current input current, thereby facilitating improving the accuracy of maximum power point tracking and the determination accuracy of the interference observation method.

[0154] A maximum power point tracking method provided by an embodiment of the present application pre-processes an output voltage and an output current collected by an output collection circuit within a preset timing execution time, determines the current output voltage according to the pre-processed output voltage, and determines the current output current according to the pre-processed output current, which may include:

[0155] The median average filtering algorithm is used to process the output voltage and output current collected by the output collection circuit within the preset timing execution time, and the corresponding output voltage and output current are obtained.

[0156] In the embodiment of the present application, a median average filtering algorithm can be specifically used to preprocess and calculate all input voltage and input current data collected by the input acquisition circuit within a preset timing execution time to obtain the corresponding input voltage and input current.

[0157] The median average filtering algorithm is used to effectively filter out accidental interference, thereby improving the accuracy of determining the current output voltage and the current output current.

[0158] A maximum power point tracking method provided by an embodiment of the present application may further include, after determining an output voltage change ratio according to the current output voltage and the previous output voltage, and determining an output current change ratio according to the current output current and the previous output current:

[0159] If the absolute value of the output voltage change ratio is not less than the first set value, the previous output voltage is updated using the current output voltage; if the absolute value of the output voltage change ratio is less than the first set value, the previous output voltage is maintained;

[0160] If the absolute value of the output current change ratio is not less than the second set value, the previous output current is updated using the current output current; if the absolute value of the output current change ratio is less than the second set value, the previous output current is maintained.

[0161] In the embodiment of the present application, after the output voltage change ratio K1 is determined according to the current output voltage and the previous output voltage, and the output current change ratio K2 is determined according to the current output current and the previous output current, for the absolute value |K1| of the output voltage change ratio K1, if |K1|≥K 10 , it indicates that the output power change causes the output voltage change. At this time, the last output voltage can be updated using the current output voltage, that is: the last output voltage = the current output voltage; if |K1| <K 10 , the output voltage may change due to the acquisition error of the output acquisition circuit, or it may change due to the output power change. At this time, the last output voltage can be maintained and the current output voltage is not saved, so that if the output power changes and the output voltage changes, the real effective value can be superimposed, so that when the output voltage change ratio is calculated and determined later, the absolute value of the output voltage change ratio can exceed the first set value, thereby improving the accuracy of the interference observation method.

[0162] For the absolute value of the output current change ratio K2 |K2|, if |K2|≥K 20 , it indicates that the output current changes due to the output power change. At this time, the last output current can be updated using the current output current, that is, the last output current = the current output current. If |K2| <K 20 , the output current may change due to the acquisition error of the output acquisition circuit, or it may change due to the output power change. At this time, the last output current can be maintained and the current output current is not saved, so that if the output power changes and the output current changes, the real effective value can be superimposed, so that when the output current change ratio is calculated and determined later, the absolute value of the output current change ratio can exceed the second set value, thereby improving the accuracy of the interference observation method.

[0163] It should be noted that in the first cycle, the current output voltage and the current output current need to be used to assign values ​​to the previous output voltage and the previous output current, that is, in the second cycle, the previous output voltage and the previous output current used to calculate the output voltage change ratio and the output current change ratio are the output voltage and the output current obtained in the first cycle. Starting from the second cycle, the previous output voltage and the previous output current can be determined according to the above-mentioned method.

[0164] Exemplarily, the operation logic of the maximum power point tracking method may be as follows:

[0165] ① The adjusted output voltage, current, input voltage and current are collected through the collection circuit, and the output voltage, output current, input voltage and input current of the voltage collection circuit are obtained accordingly. That is, the MCU collects data from the input collection circuit and the output collection circuit, and obtains the output voltage, output current, input voltage and input current of the voltage regulation circuit according to the data from the input collection circuit.

[0166] ② Perform a median average filtering calculation on the output voltage, output current, input voltage and input current data obtained within the preset timing execution time (median average filtering: remove the N maximum and minimum values, and average the remaining values).

[0167] ③ Compare the output voltage collected this time with the output voltage collected last time, and get K1=(this output voltage-last output voltage) / last output voltage. When |K1|≥0.5%, the last output voltage = this output voltage, otherwise the output voltage is not saved.

[0168] ④ Compare the output current collected this time with the output current collected last time, and obtain K2=(this output current-last output current) / last output current. When |K2|≥0.5%, the last output current=this output current, otherwise the output current is not saved.

[0169] ⑤ Compare the input voltage collected this time with the input voltage collected last time, and obtain K3=(this input voltage-last input voltage) / last input voltage. When |K3|≥0.5%, the last input voltage=this input voltage, otherwise the output voltage will not be saved.

[0170] ⑥ Compare the input current collected this time with the input current collected last time, and obtain K4=(this input current-last input current) / last input current. When |K4|≥0.5%, the last input current=this input current, otherwise the current input current will not be saved.

[0171] ⑦When the duty cycle is first executed, the duty cycle adjustment state is increasing. When |K1|<0.5% and |K2|<0.5%, the duty cycle adjustment state is maintained; otherwise, when the duty cycle adjustment state is increasing, when K1+K2≥-K1×K2, the duty cycle adjustment state is maintained as increasing, and when K1+K2<-K1×K2, the duty cycle adjustment state is changed to decreasing; when the duty cycle adjustment state is decreasing, when K1+K2≥-K1×K2, the duty cycle adjustment state is maintained as decreasing, and when K1+K2<-K1×K2, the duty cycle adjustment state is changed to increasing. The amplitudes of increasing and decreasing are the same.

[0172] Among them, 1. When |K1|<0.5% and |K2|<0.5%, if the last duty cycle adjustment state was increasing, the current duty cycle adjustment state will continue to increase; if the last duty cycle adjustment state was decreasing, the current duty cycle adjustment state will continue to decrease. 2. When |K1|≥0.5% and |K2|<0.5%, or, when |K1|<0.5% and |K2|≥0.5%, or when |K1|≥0.5% and |K2|≥0.5%, if K1+K2≥-K1×K2, the previous duty cycle adjustment state will continue to be maintained; if K1+K2<-K1×K2, the current duty cycle adjustment state will be changed.

[0173] ⑧MCU adjusts the output power once according to the duty cycle adjustment state, and the corresponding output voltage and output current change. Specifically, two-way complementary PWM or single-way PWM is used to adjust the duty cycle, and the output power of the BUCK DCDC circuit or BOOST DCDC circuit will change, and the corresponding BUCK DCDC circuit or BOOST DCDC circuit input power will also change, that is, the output power of the photovoltaic panel changes. Figure 1 As shown in the IV curve of the photovoltaic panel, when the output power of the photovoltaic panel changes, the voltage and current also change accordingly.

[0174] ⑨ Each time the process ① is executed in a loop, the processes ② to ⑧ are executed once at a fixed time. If the maximum power point flag is invalid, it is judged that the preset timing execution time is lengthened after the maximum power point is reached (that is, the cycle of executing processes ① to ⑧ becomes longer), and the maximum power point flag is marked as valid. Because our goal is to stabilize at the maximum power point, increasing the timing time can reduce the frequent oscillations near the maximum power point. When judging that the maximum power point flag is valid, once any one of the conditions |K3| ≥ 5% or |K4| ≥ 5% occurs (the above situation indicates that the input has changed, and it can be basically determined that the photovoltaic energy has changed), at this time, the maximum power point flag is invalid, and the preset timing execution time returns to normal to cope with the change in photovoltaic energy, and the tracking point can be adjusted quickly. Or K1+K2≥-K1×K2 appears after 3 consecutive adjustments (and |K1|≥K 10 and / or |K2|≥K 20 ), it is considered that the maximum power point may change. At this time, the invalid maximum power point flag is set, the preset timing execution time returns to normal, and the maximum power point is readjusted.

[0175] For example, in normal tracking, the process from ② to ⑧ is executed every 40ms. If the maximum power point flag is invalid but the maximum power point is reached, the process from ② to ⑧ is adjusted to be executed every 80ms. When the maximum power point flag is valid, once any of the conditions |K3|≥5% or |K4|≥5% occurs, or after three adjustments, K1+K2≥-K1×K2 (and |K1|≥K 10 and / or |K2|≥K 20 ), the maximum power point is marked as invalid, and the process from ② to ⑧ is adjusted again to be executed every 40ms.

[0176] Maximum power point determination: If under normal tracking, the duty cycle adjustment state changes from increasing or decreasing to the opposite state, and then changes back to the original increasing or decreasing state, and the above cycles occur continuously for more than one cycle (the greater the number of cycles, the more accurate the determination of the maximum power point, but the corresponding situation is that it is easily affected by factors such as changes in light, making it difficult to determine the maximum power point; in actual applications, it is generally set at around 2-4), then it is determined to be at the maximum power point.

[0177] The embodiment of the present application also provides a maximum power point tracking device, which is applied to a control module, the control module is connected to a voltage regulation circuit and an output acquisition circuit, the output acquisition circuit is connected between the voltage regulation circuit and the load, and the voltage regulation circuit is connected to a photovoltaic panel. The maximum power point tracking device may include: a determination module, which is used to determine the current output voltage and the current output current according to the output voltage and the output current collected by the output acquisition circuit within a preset timing execution time, determine the output voltage change ratio according to the current output voltage and the last output voltage, and determine the output current change ratio according to the current output current and the last output current; a first judgment module, which is used to judge whether the absolute value of the output voltage change ratio is less than a first set value and the output current change ratio is less than a first set value; the absolute value of the ratio is less than the second set value; if so, the adjustment direction of the working voltage of the photovoltaic panel, and the working voltage of the photovoltaic panel is adjusted according to the adjustment direction of the working voltage of the photovoltaic panel; if not, the adjustment direction of the working voltage of the photovoltaic panel is regulated according to the output voltage change ratio and the output current change ratio, and the working voltage of the photovoltaic panel is adjusted according to the adjustment direction of the working voltage of the photovoltaic panel; a second judgment module is used to judge whether it is at the maximum power point or whether the maximum power point flag is valid, determine the preset timing execution time according to the judgment result, and return to execute the step of determining the output voltage and the output current corresponding to the output voltage and the output current collected by the output collection circuit within the preset timing execution time after the preset timing execution time is reached.

[0178] A maximum power point tracking device provided by an embodiment of the present application, wherein a first judgment module may include: a maintenance submodule, used to maintain the first duty cycle adjustment state in the previous cycle, obtain the first duty cycle adjustment state in this cycle, obtain the current PWM signal according to the first duty cycle adjustment state in this cycle, and adjust the output power of the voltage regulation circuit according to the current PWM signal to adjust the working voltage of the photovoltaic panel; a control submodule, used to obtain the first duty cycle adjustment state in this cycle according to the output voltage change ratio, the output current change ratio and the first duty cycle adjustment state in the previous cycle, obtain the current PWM signal according to the first duty cycle adjustment state in this cycle, and adjust the output power of the voltage regulation circuit according to the current PWM signal to adjust the working voltage of the photovoltaic panel;

[0179] The first duty cycle adjustment state includes increasing and decreasing.

[0180] A maximum power point tracking device provided by an embodiment of the present application, the control submodule may include: a first judgment unit, used to judge whether the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio; a maintaining unit, used to maintain the adjustment state of the first duty cycle in the previous cycle if the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio, and obtain the first duty cycle adjustment state in this cycle; an adjusting unit, used to obtain the first duty cycle adjustment state in this cycle as decreasing when the first duty cycle adjustment state in the previous cycle is increasing, and obtain the first duty cycle adjustment state in this cycle as increasing when the first duty cycle adjustment state in the previous cycle is decreasing.

[0181] A maximum power point tracking device provided by an embodiment of the present application, wherein the maintaining submodule and the regulating submodule may include: a first determining unit, configured to determine whether the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle if the first duty cycle adjustment state in this cycle is increasing; if the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle, determine that the duty cycle in the current PWM signal is equal to the maximum duty cycle; if the sum of the current duty cycle and the duty cycle adjustment value is not greater than the maximum duty cycle, determine that the duty cycle in the current PWM signal is equal to the maximum duty cycle. The duty cycle is equal to the sum of the current duty cycle and the duty cycle adjustment value; the second determination unit is used to determine whether the difference between the current duty cycle and the duty cycle adjustment value is less than the minimum duty cycle if the first duty cycle adjustment state in this cycle is decreasing; if the difference between the current duty cycle and the duty cycle adjustment value is less than the minimum duty cycle, it is determined that the duty cycle in the current PWM signal is equal to the minimum duty cycle; if the difference between the current duty cycle and the duty cycle adjustment value is not less than the minimum duty cycle, it is determined that the duty cycle in the current PWM signal is equal to the difference between the current duty cycle and the duty cycle adjustment value.

[0182] A maximum power point tracking device provided by an embodiment of the present application, the second judgment module may include: a first judgment submodule, used to judge whether the maximum power point flag is valid; a first determination submodule, used to judge whether it is at the maximum power point if the maximum power point flag is invalid; if not at the maximum power point, determine the preset timing execution time as the first timing execution time; if at the maximum power point, mark the maximum power point flag as valid, and determine the preset timing execution time as the second timing execution time; the second determination submodule, used to determine the preset timing execution time as the second timing execution time if the maximum power point flag is valid; wherein the second timing execution time is greater than the first timing execution time.

[0183] In a maximum power point tracking device provided by an embodiment of the present application, the second judgment module may further include: a second judgment submodule, which is used to determine whether the maximum power point flag should be invalid before determining the preset timing execution time as the second timing execution time if the maximum power point flag is determined to be valid; a third determination submodule, which is used to update the maximum power point flag to invalid if the maximum power point flag should be invalid, and determine the preset timing execution time as the first timing execution time; and an execution submodule, which is used to execute the step of determining the preset timing execution time as the second timing execution time if the maximum power point flag should not be invalid.

[0184] In a maximum power point tracking device provided by an embodiment of the present application, the control module is also connected to an input acquisition circuit, and the input acquisition circuit is connected between the photovoltaic panel and the voltage regulation circuit. The second judgment module may also include: a fourth determination submodule, which is used to determine the current input voltage and the current input current according to the input voltage and the input current collected by the input acquisition circuit within a preset timing execution time before judging whether the maximum power point flag should be invalid, determine the input voltage change ratio according to the current input voltage and the previous input voltage, and determine the input current change ratio according to the current input current and the previous input current;

[0185] The second judgment submodule may include: a second judgment unit, used to judge whether the absolute value of the input voltage change ratio is not less than the third set value or the absolute value of the input current change ratio is not less than the fourth set value, or whether it occurs N1 times in a row: the absolute value of the output voltage change ratio is not less than the first set value, the absolute value of the output current change ratio is not less than at least one of the second set value and the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio; N1 is an integer greater than 0; a third determination unit, used if the absolute value of the input voltage change ratio is not less than the third set value or the absolute value of the input current change ratio is not less than the fourth set value, or, it occurs N1 times in a row: the absolute value of the output voltage change ratio is not less than the first set value The maximum power point flag is determined to be invalid if the absolute value of the set value and the absolute value of the output current change ratio are not less than at least one of the second set values ​​and the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio; a fourth determination unit is used to determine that the maximum power point flag should not be invalid if the absolute value of the input voltage change ratio is less than the third set value and the absolute value of the input current change ratio is less than the fourth set value, and it does not occur N1 times in a row: the absolute value of the output voltage change ratio is not less than the first set value and / or the absolute value of the output current change ratio is not less than at least one of the second set values ​​and the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio.

[0186] A maximum power point tracking device provided in an embodiment of the present application, the fourth determination submodule may include: a fifth determination unit, used to preprocess the input voltage and input current collected by the input acquisition circuit within a preset timing execution time, determine the current input voltage according to the preprocessed input voltage, and determine the current input current according to the preprocessed input current.

[0187] In a maximum power point tracking device provided by an embodiment of the present application, the second judgment module may also include: a first updating and maintaining submodule, which is used to determine the input voltage change ratio according to the current input voltage and the last input voltage, and determine the input current change ratio according to the current input current and the last input current. If the absolute value of the input voltage change ratio is not less than the fifth set value, the last input voltage is updated with the current input voltage; if the absolute value of the input voltage change ratio is less than the fifth set value, the last input voltage is maintained; a second updating and maintaining submodule, which is used to update the last input current with the current input current if the absolute value of the input current change ratio is not less than the sixth set value; if the absolute value of the input current change ratio is less than the sixth set value, the last input current is maintained.

[0188] In a maximum power point tracking device provided by an embodiment of the present application, the control submodule may further include: an assignment unit, which is used to assign the second duty cycle adjustment state to the third duty cycle adjustment state and the first duty cycle adjustment state to the second duty cycle adjustment state before obtaining the first duty cycle adjustment state in this cycle if it is determined that the sum of the output voltage change ratio and the output current change ratio is less than the inverse of the product of the output voltage change ratio and the output current change ratio;

[0189] The first determination submodule may include: a third judgment unit, used to judge whether the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and whether the third duty cycle adjustment state is equal to the first duty cycle adjustment state; a fourth judgment unit, used to control n to add 1 if the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and the third duty cycle adjustment state is equal to the first duty cycle adjustment state, and judge whether n is greater than or equal to N2, if n is greater than or equal to N2, it is determined to be at the maximum power point, if n is less than N2, control n to be equal to 0 and determine that it is not at the maximum power point; n is the number of consecutive occurrences of the second duty cycle adjustment state not equal to the third duty cycle adjustment state and the third duty cycle adjustment state equal to the first duty cycle adjustment state, and N2 is an integer greater than 0; a sixth determination unit, used to control n to be equal to 0 and determine that it is not at the maximum power point if it is not satisfied that: the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and the third duty cycle adjustment state is equal to the first duty cycle adjustment state.

[0190] A maximum power point tracking device provided in an embodiment of the present application, wherein the determination module may include: a preprocessing determination submodule, which is used to preprocess the output voltage and output current collected by the output collection circuit within a preset timing execution time, determine the current output voltage according to the preprocessed output voltage, and determine the current output current according to the preprocessed output current.

[0191] A maximum power point tracking device provided in an embodiment of the present application, the preprocessing determination submodule may include: a processing unit, used to use a median average filtering algorithm to process the output voltage and output current collected by the output acquisition circuit within a preset timing execution time, and obtain the corresponding output voltage and output current.

[0192] A maximum power point tracking device provided by an embodiment of the present application may also include: a first updating and maintaining module, which is used to update the last output voltage with the current output voltage if the absolute value of the output voltage change ratio is not less than the first set value after determining the output voltage change ratio according to the current output voltage and the last output voltage, and determining the output current change ratio according to the current output current and the last output current; if the absolute value of the output voltage change ratio is less than the first set value, maintain the last output voltage; a second updating and maintaining module, which is used to update the last output current with the current output current if the absolute value of the output current change ratio is not less than the second set value; if the absolute value of the output current change ratio is less than the second set value, maintain the last output current.

[0193] The present application also provides a maximum power point tracking system. Figure 2 , may include an output acquisition circuit connected between a voltage regulation circuit and a load, and a control module connected to the output acquisition circuit and the voltage regulation circuit, wherein the voltage regulation circuit is connected to a photovoltaic panel; the output acquisition circuit is used to acquire the output voltage and output current of the voltage regulation circuit; and the control module is used to implement the steps of any of the above-mentioned maximum power point tracking methods.

[0194] A maximum power point tracking system provided in an embodiment of the present application may also include an input acquisition circuit connected between the photovoltaic panel and the voltage regulation circuit and connected to the control module; the input acquisition circuit is used to collect the input voltage and input current of the voltage regulation circuit.

[0195] A maximum power point tracking system is provided in an embodiment of the present application. The control module may include an MCU and a driving circuit connected between the MCU and the voltage regulation circuit. The MCU determines a first duty cycle adjustment state in this cycle, and adjusts the current PWM signal according to the first duty cycle adjustment state in this cycle to achieve the control of the working voltage of the photovoltaic panel.

[0196] The embodiment of the present application also provides a control module, which is connected to the voltage regulation circuit and the output acquisition circuit, the output acquisition circuit is connected between the voltage regulation circuit and the load, and the voltage regulation circuit is connected to the photovoltaic panel; the control module is used to implement the steps of any of the above-mentioned maximum power point tracking methods.

[0197] The description of the relevant parts of a maximum power point tracking device, system and control module provided in the embodiments of the present application can be found in the detailed description of the corresponding parts of a maximum power point tracking method provided in the embodiments of the present application, and will not be repeated here.

[0198] It should be noted that the logic and / or steps represented in the flowchart or described in other ways herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or equipment (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or equipment and execute instructions), or in combination with these instruction execution systems, devices or equipment. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or equipment, or in combination with these instruction execution systems, devices or equipment. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and editable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0199] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0200] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0201] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. Moreover, in the description of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects associated before and after are in an "or" relationship.

[0202] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0203] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A maximum power point tracking method, characterized in that: Applied to a control module, the control module is connected to a voltage regulation circuit and an output acquisition circuit, the output acquisition circuit is connected between the voltage regulation circuit and a load, the voltage regulation circuit is connected to a photovoltaic panel, and the maximum power point tracking method includes: Determine the current output voltage and the current output current according to the output voltage and the output current collected by the output collection circuit within the preset timing execution time, determine the output voltage change ratio according to the current output voltage and the previous output voltage, and determine the output current change ratio according to the current output current and the previous output current; Determine whether the absolute value of the output voltage change ratio is less than a first set value and the absolute value of the output current change ratio is less than a second set value; if so, maintain the adjustment direction of the working voltage of the photovoltaic panel, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; if not, regulate the adjustment direction of the working voltage of the photovoltaic panel according to the output voltage change ratio and the output current change ratio, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; Determine whether it is at the maximum power point or whether the maximum power point flag is valid, determine the preset timing execution time according to the determination result, and return to the step of determining the current output voltage and the current output current according to the output voltage and the output current collected by the output collection circuit within the preset timing execution time after the preset timing execution time is reached; Determining whether the device is at a maximum power point or whether a maximum power point flag is valid, and determining the preset timing execution time according to the determination result, including: Determine whether the maximum power point flag is valid; If the maximum power point flag is invalid, determine whether it is at the maximum power point; if it is not at the maximum power point, determine the preset timing execution time as the first timing execution time; if it is at the maximum power point, mark the maximum power point flag as valid, and determine the preset timing execution time as the second timing execution time; If the maximum power point flag is valid, determining the preset timing execution time as the second timing execution time; Wherein, the second scheduled execution time is greater than the first scheduled execution time; If it is determined that the maximum power point flag is valid, before determining that the preset timing execution time is the second timing execution time, the method further includes: Determining whether the maximum power point flag should be invalid; If yes, updating the maximum power point flag to invalid, and determining the preset timing execution time to be the first timing execution time; If not, executing the step of determining the preset scheduled execution time as the second scheduled execution time; The control module is also connected to an input acquisition circuit, which is connected between the photovoltaic panel and the voltage regulation circuit. Before determining whether the maximum power point flag should be invalid, the control module further includes: Determine the current input voltage and current according to the input voltage and input current collected by the input collection circuit within the preset timing execution time, determine the input voltage change ratio according to the current input voltage and the previous input voltage, and determine the input current change ratio according to the current input current and the previous input current; Determining whether the maximum power point flag should be invalid includes: Determine whether the absolute value of the input voltage change ratio is not less than a third set value or the absolute value of the input current change ratio is not less than a fourth set value, or whether it occurs N1 times in succession: the absolute value of the output voltage change ratio is not less than the first set value, the absolute value of the output current change ratio is not less than the second set value, and the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio; N1 is an integer greater than 0; If yes, it is determined that the maximum power point flag should be invalid; If not, it is determined that the maximum power point flag bit should not be invalid.

2. The maximum power point tracking method according to claim 1, characterized in that: Maintaining the adjustment direction of the working voltage of the photovoltaic panel, and adjusting the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel, comprising: Maintaining the first duty cycle adjustment state in the previous cycle, obtaining the first duty cycle adjustment state in this cycle, obtaining the current PWM signal according to the first duty cycle adjustment state in this cycle, and adjusting the output power of the voltage regulation circuit according to the current PWM signal to adjust the working voltage of the photovoltaic panel; The method comprises: regulating the adjustment direction of the working voltage of the photovoltaic panel according to the output voltage change ratio and the output current change ratio, and adjusting the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel, comprising: According to the output voltage change ratio, the output current change ratio and the first duty cycle adjustment state in the previous cycle, the first duty cycle adjustment state in this cycle is obtained, according to the first duty cycle adjustment state in this cycle, the current PWM signal is obtained, and according to the current PWM signal, the output power of the voltage regulation circuit is adjusted to adjust the working voltage of the photovoltaic panel; The first duty cycle adjustment state includes increasing and decreasing.

3. The maximum power point tracking method according to claim 2, characterized in that: According to the output voltage change ratio, the output current change ratio and the first duty cycle adjustment state in the previous cycle, the first duty cycle adjustment state in this cycle is obtained, including: Determine whether the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio; If yes, the first duty cycle adjustment state in the previous cycle is maintained to obtain the first duty cycle adjustment state in this cycle; If not, when the first duty cycle adjustment state in the previous cycle is increasing, the first duty cycle adjustment state in this cycle is decreasing, and when the first duty cycle adjustment state in the previous cycle is decreasing, the first duty cycle adjustment state in this cycle is increasing.

4. The maximum power point tracking method according to claim 3, characterized in that: The PWM signal of this cycle is obtained according to the first duty cycle adjustment state in this cycle, including: If the first duty cycle adjustment state in this cycle is increasing, it is determined whether the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle value; if the sum of the current duty cycle and the duty cycle adjustment value is greater than the maximum duty cycle value, it is determined that the duty cycle in the current PWM signal is equal to the maximum duty cycle value; if the sum of the current duty cycle and the duty cycle adjustment value is not greater than the maximum duty cycle value, it is determined that the duty cycle in the current PWM signal is equal to the sum of the current duty cycle and the duty cycle adjustment value; If the first duty cycle adjustment state in this cycle is decreasing, determine whether the difference between the current duty cycle and the duty cycle adjustment value is less than the minimum duty cycle value; if the difference between the current duty cycle and the duty cycle adjustment value is less than the minimum duty cycle value, determine that the duty cycle in this PWM signal is equal to the minimum duty cycle value; if the difference between the current duty cycle and the duty cycle adjustment value is not less than the minimum duty cycle value, determine that the duty cycle in this PWM signal is equal to the difference between the current duty cycle and the duty cycle adjustment value.

5. The maximum power point tracking method according to claim 1, characterized in that: Determining the current input voltage and the current input current according to the input voltage and the input current collected by the input collection circuit within the preset timing execution time includes: The input voltage and input current collected by the input collection circuit within the preset timing execution time are preprocessed, and the current input voltage is determined according to the preprocessed input voltage, and the current input current is determined according to the preprocessed input current.

6. The maximum power point tracking method according to claim 1, characterized in that: After determining the input voltage change ratio according to the current input voltage and the last input voltage, and determining the input current change ratio according to the current input current and the last input current, the method further includes: If the absolute value of the input voltage change ratio is not less than the fifth set value, the last input voltage is updated using the current input voltage; if the absolute value of the input voltage change ratio is less than the fifth set value, the last input voltage is maintained; If the absolute value of the input current change ratio is not less than the sixth set value, the last input current is updated using the current input current; if the absolute value of the input current change ratio is less than the corresponding sixth set value, the last input current is maintained.

7. The maximum power point tracking method according to claim 1, characterized in that: If it is determined that the sum of the output voltage change ratio and the output current change ratio is less than the inverse of the product of the output voltage change ratio and the output current change ratio, before obtaining the first duty cycle adjustment state in this cycle, the method further includes: Assigning the second duty cycle adjustment state to the third duty cycle adjustment state, and assigning the first duty cycle adjustment state to the second duty cycle adjustment state; Determine whether it is at the maximum power point, including: determining whether the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and whether the third duty cycle adjustment state is equal to the first duty cycle adjustment state; If yes, then control n to add 1, and determine whether n is greater than or equal to N2, if n is greater than or equal to N2, it is determined to be at the maximum power point, if n is less than N2, control n to be equal to 0 and determine not to be at the maximum power point; n is the number of times that the second duty cycle adjustment state is not equal to the third duty cycle adjustment state and the third duty cycle adjustment state is equal to the first duty cycle adjustment state, and N2 is an integer greater than 0; If not, n is controlled to be equal to 0 and it is determined that the maximum power point is not reached.

8. The maximum power point tracking method according to claim 1, characterized in that: Determining the current output voltage and the current output current according to the output voltage and the output current collected by the output collection circuit within the preset timing execution time includes: The output voltage and output current collected by the output collection circuit within the preset timing execution time are preprocessed, and the current output voltage is determined according to the preprocessed output voltage, and the current output current is determined according to the preprocessed output current.

9. The maximum power point tracking method according to claim 8, characterized in that: Preprocessing the output voltage and output current collected by the output collection circuit within the preset timing execution time, determining the current output voltage according to the preprocessed output voltage, and determining the current output current according to the preprocessed output current, including: The output voltage and output current collected by the output acquisition circuit within the preset timing execution time are processed by using a median average filtering algorithm to obtain the current output voltage and the current output current.

10. The maximum power point tracking method according to any one of claims 1 to 9, characterized in that: After determining the output voltage change ratio according to the current output voltage and the previous output voltage, and determining the output current change ratio according to the current output current and the previous output current, the method further includes: If the absolute value of the output voltage change ratio is not less than the first set value, the previous output voltage is updated using the current output voltage; if the absolute value of the output voltage change ratio is less than the first set value, the previous output voltage is maintained; If the absolute value of the output current change ratio is not less than the second set value, the previous output current is updated using the current output current; if the absolute value of the output current change ratio is less than the corresponding second set value, the previous output current is maintained.

11. A maximum power point tracking device, characterized in that: Applied to a control module, the control module is connected to a voltage regulating circuit and an output acquisition circuit, the output acquisition circuit is connected between the voltage regulating circuit and a load, the voltage regulating circuit is connected to a photovoltaic panel, and the maximum power point tracking device includes: A determination module, used to determine the current output voltage and the current output current according to the output voltage and the output current collected by the output collection circuit within a preset timing execution time, determine the output voltage change ratio according to the current output voltage and the previous output voltage, and determine the output current change ratio according to the current output current and the previous output current; A first judgment module is used to judge whether the absolute value of the output voltage change ratio is less than a first set value and the absolute value of the output current change ratio is less than a second set value; if so, maintain the adjustment direction of the working voltage of the photovoltaic panel, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; if not, regulate the adjustment direction of the working voltage of the photovoltaic panel according to the output voltage change ratio and the output current change ratio, and adjust the working voltage of the photovoltaic panel according to the adjustment direction of the working voltage of the photovoltaic panel; The second judgment module is used to judge whether it is at the maximum power point or whether the maximum power point flag is valid, determine the preset timing execution time according to the judgment result, and return to execute the step of determining the current output voltage and the current output current according to the output voltage and the output current collected by the output collection circuit within the preset timing execution time after the preset timing execution time is reached; The second judgment module is specifically used to: judge whether the maximum power point flag is valid; If the maximum power point flag is invalid, determine whether it is at the maximum power point; if it is not at the maximum power point, determine the preset timing execution time as the first timing execution time; if it is at the maximum power point, mark the maximum power point flag as valid, and determine the preset timing execution time as the second timing execution time; If the maximum power point flag is valid, determining the preset timing execution time as the second timing execution time; Wherein, the second scheduled execution time is greater than the first scheduled execution time; The second judgment module is further used to: judge whether the maximum power point flag should be invalid; If yes, updating the maximum power point flag to invalid, and determining the preset timing execution time to be the first timing execution time; If not, executing the step of determining the preset scheduled execution time as the second scheduled execution time; The control module is also connected to an input acquisition circuit, and the input acquisition circuit is connected between the photovoltaic panel and the voltage regulation circuit. Before determining whether the maximum power point flag should be invalid, the second judgment module is also used to: Determine the current input voltage and current according to the input voltage and input current collected by the input collection circuit within the preset timing execution time, determine the input voltage change ratio according to the current input voltage and the previous input voltage, and determine the input current change ratio according to the current input current and the previous input current; The second judgment module is also used for: Determine whether the absolute value of the input voltage change ratio is not less than a third set value or the absolute value of the input current change ratio is not less than a fourth set value, or whether it occurs N1 times in succession: the absolute value of the output voltage change ratio is not less than the first set value, the absolute value of the output current change ratio is not less than the second set value, and the sum of the output voltage change ratio and the output current change ratio is greater than or equal to the inverse of the product of the output voltage change ratio and the output current change ratio; N1 is an integer greater than 0; If yes, it is determined that the maximum power point flag should be invalid; If not, it is determined that the maximum power point flag bit should not be invalid.

12. A maximum power point tracking system, characterized in that: It includes an output acquisition circuit connected between a voltage regulating circuit and a load, and a control module connected to the output acquisition circuit and the voltage regulating circuit, wherein the voltage regulating circuit is connected to a photovoltaic panel; The output acquisition circuit is used to collect the output voltage and output current of the voltage regulation circuit; The control module is used to implement the steps of the maximum power point tracking method as described in any one of claims 1 to 10.

13. The maximum power point tracking system according to claim 12, characterized in that: It also includes an input acquisition circuit connected between the photovoltaic panel and the voltage regulation circuit and connected to the control module; The input acquisition circuit is used to acquire the input voltage and input current of the voltage regulation circuit.

14. The maximum power point tracking system according to claim 12, characterized in that: The control module includes an MCU and a driving circuit connected between the MCU and the voltage regulation circuit. The MCU determines a first duty cycle adjustment state in this cycle, and adjusts the current PWM signal according to the first duty cycle adjustment state in this cycle to achieve regulation of the working voltage of the photovoltaic panel.

15. A control module, characterized in that: The control module is connected to a voltage regulating circuit and an output collection circuit, the output collection circuit is connected between the voltage regulating circuit and a load, and the voltage regulating circuit is connected to a photovoltaic panel; The control module is used to implement the steps of the maximum power point tracking method as described in any one of claims 1 to 10.

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