Frequency converter control method for photovoltaic MPPT panel, computer readable storage medium and air conditioner

Abstract

According to the frequency converter control method for the photovoltaic MPPT board, the computer readable storage medium and the air conditioner, a program is started, voltage sampling is carried out through a sampling circuit, and AveVdc and ErrVdc are obtained; a fuzzy PID controller is substituted, fuzzy PID control is designed as the input quantity of the fuzzy controller, a simulation model is built, and the reliability of the algorithm is verified; the algorithm is written into a program, whether the frequency converter rotating speed Wr is larger than the frequency converter minimum rotating speed WrMin or not is judged, when the frequency converter rotating speed Wr is smaller than the frequency converter minimum rotating speed WrMin, the frequency converter stops at the minimum rotating speed, and large impact current cannot be brought to frequency converter hardware; fuzzy control is adopted in combination with the actual test condition, the output rotating speed of the frequency converter is dynamically adjusted according to the bus voltage, it is guaranteed that the frequency converter can change the consumed power along with the power supplied by the MPPT photovoltaic panel under the change of the complex illumination condition, and the effect of shutdown without abnormal faults is achieved.

Description

[Technical field]

[0001] The present invention relates to photovoltaic air-conditioning frequency conversion control technology, and in particular to a frequency converter control method for a photovoltaic MPPT panel, a computer-readable storage medium and an air-conditioning. [Background technology]

[0002] The MPPT controller can detect the power generation voltage of the solar panel in real time and track the maximum voltage and current value (VI), so that the system can charge the battery with maximum power output. Applied in solar photovoltaic systems, it coordinates the work of solar panels, batteries, and loads, and is the brain of the photovoltaic system. The main function of MPPT technology is to improve the output efficiency of power generation equipment and ensure that the maximum power can be output under various environmental conditions. In photovoltaic solar energy systems, MPPT technology is implemented through inverters, which can ensure that solar panels can output maximum power under various weather conditions, meet household electricity needs and reduce electricity bills.

[0003] However, when the inverter is powered by a MPPT photovoltaic panel and the photovoltaic and municipal power are mixed, the following situations may occur: (1) The photovoltaic and municipal power supply work simultaneously to provide stable power supply; (2) As the light conditions change, the power supplied by the MPPT photovoltaic panel decreases and is switched to the municipal power supply. When the light conditions improve, the inverter is powered by the MPPT photovoltaic power supply again; (3) The municipal power supply is disconnected and the inverter is completely powered by the photovoltaic power supply of the MPPT photovoltaic panel. As the light conditions continue to decrease, the power required by the inverter also decreases.

[0004] However, in order to save costs, the communication between the MPPT board and the inverter is not set up under the existing hardware topology, resulting in the inverter being unable to accurately know how the photovoltaic power supply situation changes. Once the lighting conditions change drastically, the power supplied by the MPPT photovoltaic panel will change rapidly. If not processed, it will cause the inverter to malfunction and shut down, giving users a bad experience.

[0005] Therefore, there is an urgent need to improve the control mode of the existing photovoltaic system to solve the control needs when the mains power supply is unstable and to ensure control under complex conditions of changing light conditions. [Summary of the invention]

[0006] The present invention provides a frequency converter control method for a photovoltaic MPPT panel, which adopts fuzzy control and effectively ensures stable operation and trouble-free shutdown of the compressor under complex changes in lighting conditions when the mains power supply is unstable, thereby maximizing the user experience.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0008] A method for controlling a frequency converter of a photovoltaic MPPT panel comprises the following steps:

[0009] S1. The program starts and voltage sampling is performed through the sampling circuit;

[0010] S2. Get Ave_Vdc and Err_Vdc;

[0011] S3. Bring in the fuzzy PID controller and use Ave_Vdc and Err_Vdc as the input of the fuzzy controller to design the fuzzy PID control;

[0012] A simulation model is built by fuzzy control to verify the reliability of the algorithm;

[0013] S4. Then write the algorithm into the program to obtain the inverter speed Wr;

[0014] S5. Determine whether the inverter speed Wr is greater than the inverter minimum speed Wr_Min;

[0015] When the inverter speed Wr is greater than or equal to the inverter minimum speed Wr_Min, the inverter continues to run until it ends;

[0016] When the power supplied by MPPT is insufficient to maintain the power consumed by the inverter due to changes in light conditions, the inverter speed Wr is actively reduced through the algorithm to reduce the power required by the inverter, ensuring that the bus voltage will not experience violent fluctuations and cause fault shutdown;

[0017] When the power supplied by MPPT to the inverter continues to drop to the point where it cannot meet the power required for the inverter's minimum speed, that is, when the inverter speed Wr is less than the inverter's minimum speed Wr_Min, the inverter shuts down at the minimum speed and does not bring a large impact current to the inverter hardware.

[0018] Furthermore, the step S3 specifically includes:

[0019] S3.1 First, the system transfer function is obtained as The fuzzy PID controller is designed by MATLAB. Through the FUZZY editor, the input values ​​are Ave_Vdc and Err_Vdc, and the output values ​​are Kp, Ki, and Kd. The input and output both use the triangular membership function trimf, as shown in Formula 1.

[0020]

[0021] Among them, the domain of Ave_Vdc and Err_Vdc is [-6, 6], the domain of KP is [2, 5], the domain of Ki is [1, 3], and the domain of Kd is [7, 19];

[0022] S3.2 Then, edit the fuzzy rules according to the fuzzy table of proportional parameter P in Table 1, the fuzzy table of integral parameter i in Table 2, and the fuzzy table of calculus parameter d in Table 3;

[0023] Table 1

[0024]

[0025] Table 2

[0026]

[0027] Table 3

[0028]

[0029]

[0030] In Tables 1, 2 and 3, NL means negative large, NM means negative medium, NS means negative small, ZE means zero, PS means positive small, PM means positive medium, and PB means positive large;

[0031] The S3.3 program provides the value of the maximum membership output to resolve the fuzziness;

[0032] Select the element with the largest membership in the fuzzy set of the inference result as the output value, that is, V0 = maxμ v (v);

[0033] If there is more than one output value corresponding to the maximum membership in the output domain V, then the average value of the output with the maximum membership is taken, that is, v i =max(μ v (v));

[0034] S3.4 Then, a simulation model is built through simulink to verify the reliability of the algorithm;

[0035] S3.5 From the simulation results, it can be seen that when the input power of the MPPT photovoltaic panel changes, the inverter power adjusts the speed at a faster speed to ensure that the power consumption basically follows the photovoltaic supply power to ensure operational stability.

[0036] Another object of the present invention is to provide an information data processing terminal for implementing the inverter control method for a photovoltaic MPPT panel.

[0037] Another object of the present invention is to provide a computer-readable storage medium for storing a computer program, wherein the computer program, when called by a processor, implements the inverter control method for a photovoltaic MPPT panel.

[0038] Another object of the present invention is to provide an air conditioner, comprising a processor and a memory, wherein the memory is used to store a computer program, and when the computer program is called by the processor, the inverter control method for a photovoltaic MPPT panel is implemented.

[0039] The beneficial effects of the present invention are:

[0040] In order to solve the problem that the power supplied by the MPPT photovoltaic panel changes rapidly due to drastic changes in lighting conditions, in this embodiment, a fuzzy control mode is adopted, and the fluctuation value and average value of the bus voltage are taken as input. The outputs are KP, KI, and KD, all of which adopt triangular membership functions, and the traditional PID fuzzy rule table is used to design the fuzzy controller, and the parameters are adjusted according to the actual situation. When the mains power supply is unstable and the lighting conditions change complexly, the stable operation and trouble-free shutdown of the compressor are effectively guaranteed, thereby maximizing the user experience. The detection method adopts a pure software method, without the need for additional hardware detection circuits, effectively reducing the control cost.

[0041] In the present invention, by adding a control algorithm to the inverter matching the MPPT photovoltaic panel, for the existing economical hardware topology, the MPPT photovoltaic panel and the inverter have no communication data transmission, and by analyzing this control system, a transfer function is established, and then according to Ave_Vdc, Err_Vdc as input values, Kp, Ki, Kd as output values, a fuzzy controller with a triangular membership function of 7 membership degrees is used to construct a corresponding control algorithm and add it to the sensorless FOC algorithm, so as to ensure that the inverter speed of the inverter matching the MPPT photovoltaic panel automatically changes with the power size provided by the MPPT, and ensure that the inverter will not abnormally shut down due to voltage fluctuations, improve user experience, and even if the power supplied by the MPPT photovoltaic panel is insufficient to maintain the power required for the minimum speed of the inverter, it will not cause a large impact current to appear, thereby protecting the inverter. That is, by combining the actual test situation, fuzzy PID control is adopted to dynamically adjust the output speed of the inverter according to the bus voltage, so as to ensure that under the change of complex lighting conditions, the inverter can change its own power consumption according to the power supplied by the MPPT photovoltaic panel, so as to achieve the effect of no abnormal fault shutdown.

Brief Description of the Drawings

[0042] Figure 1 It is the design diagram of the FUZZY editor in the present invention;

[0043] Figure 2 is the domain diagram of Err_Vdc in the present invention;

[0044] Figure 3 is the domain diagram of Ave_Vdc in the present invention;

[0045] Figure 4 is the domain graph of KP in the present invention;

[0046] Figure 5 is the domain graph of Ki in the present invention;

[0047] Figure 6 is the domain diagram of Kd in the present invention;

[0048] Figure 7 is the editing diagram of the fuzzy rules in the present invention;

[0049] Figure 8 It is a simulation model diagram constructed by simulink in the present invention;

[0050] Fig. 9 It is a simulation result diagram of the present invention using simulink simulation;

[0051] Fig.10 It is a waveform diagram when the power supplied by the MPPT photovoltaic panel suddenly drops, measured after the algorithm in the present invention is written into the program;

[0052] Fig.11 It is a waveform diagram when the power measured after the algorithm in the present invention is written into the program drops to the power required for the minimum operating frequency and stops without fault;

[0053] Fig.12 It is a control flow chart of the present invention. [Specific implementation method]

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary persons in the art without creative work are within the scope of protection of the present invention.

[0055] A frequency converter control method for a photovoltaic MPPT panel, such as Fig.12 As shown, the following steps are included:

[0056] S1. The program starts and voltage sampling is performed through the sampling circuit;

[0057] S2. Get Ave_Vdc and Err_Vdc;

[0058] S3. Bring in the fuzzy PID controller and use Ave_Vdc and Err_Vdc as the input of the fuzzy controller to design the fuzzy PID control;

[0059] S3.1 First, the system transfer function is obtained as Design a fuzzy PID controller using MATLAB, such as Figure 1As shown, through the FUZZY editor, the input values ​​are Ave_Vdc, Err_Vdc, and the output values ​​are Kp, Ki, and Kd. The input and output both use the triangle membership function trimf, as shown in formula 1.

[0060]

[0061] Among them, Figures 2 to 6 As shown, the domain of Ave_Vdc and Err_Vdc is [-6, 6], the domain of KP is [2, 5], the domain of Ki is [1, 3], and the domain of Kd is [7, 19];

[0062] S3.2 Then, if Figure 7 As shown, the fuzzy rules are edited according to the fuzzy table of proportional parameter P in Table 1, the fuzzy table of integral parameter i in Table 2, and the fuzzy table of calculus parameter d in Table 3;

[0063] Table 1

[0064]

[0065]

[0066] Table 2

[0067]

[0068] Table 3

[0069]

[0070]

[0071] In Tables 1, 2 and 3, NL means negative large, NM means negative medium, NS means negative small, ZE means zero, PS means positive small, PM means positive medium, and PB means positive large;

[0072] The S3.3 program provides the value of the maximum membership output to resolve the fuzziness;

[0073] Select the element with the largest membership in the fuzzy set of the inference result as the output value, that is, V0 = maxμ v (v);

[0074] If there is more than one output value corresponding to the maximum membership in the output domain V, then the average value of the output with the maximum membership is taken, that is, v i =max(μ v (v));

[0075] S3.4 Then, a simulation model is built through simulink to verify the reliability of the algorithm;

[0076] S3.5 From the simulation results, it can be seen that when the input power of the MPPT photovoltaic panel changes, the inverter power adjusts the speed at a faster speed to ensure that the power consumption basically follows the photovoltaic supply power to ensure operational stability;

[0077] S4. Then write the algorithm into the program to obtain the inverter speed Wr;

[0078] S5. Determine whether the inverter speed Wr is greater than the inverter minimum speed Wr_Min. The measured waveform is as follows: Fig.10 and Fig.11 As shown;

[0079] When the inverter speed Wr is greater than or equal to the inverter minimum speed Wr_Min, the inverter continues to run until it ends;

[0080] like Fig.10 As shown in the figure, when the power supplied by the MPPT is insufficient to maintain the power consumed by the inverter due to changes in light conditions, the inverter speed Wr is actively reduced through the above algorithm to reduce the power required by the inverter, ensuring that the bus voltage will not experience violent fluctuations and cause fault shutdown;

[0081] like Fig.11 As shown in the figure, when the power supplied by the MPPT to the inverter continues to drop to the point where it cannot meet the power required by the inverter's minimum speed, that is, when the inverter speed Wr is less than the inverter's minimum speed Wr_Min, the inverter shuts down at the minimum speed, which will not bring a large impact current to the inverter hardware.

[0082] In this embodiment, for the existing economical hardware topology, there is no communication data transmission between the MPPT photovoltaic panel and the inverter. By analyzing the control system, a transfer function is established, and then Ave_Vdc and Err_Vdc are used as input values, Kp, Ki, and Kd are designed as output values. A fuzzy controller with a triangular membership function of 7 membership degrees is used to construct a corresponding control algorithm and add it to the sensorless FOC algorithm. By combining the actual test situation, fuzzy PID control is used to dynamically adjust the output speed of the inverter according to the bus voltage to ensure that under complex lighting conditions, the inverter can change its own power consumption following the power supplied by the MPPT photovoltaic panel, so as to achieve the effect of shutdown without abnormal faults.

[0083] The above-described embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Except for the cases listed in the specific embodiments, all equivalent changes made according to the shape, structure and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A frequency converter control method for a photovoltaic MPPT panel, characterized in that: The following steps are involved: S1. The program starts and voltage sampling is performed through the sampling circuit; S2. Get Ave_Vdc and Err_Vdc; S3. Bring in the fuzzy PID controller and use Ave_Vdc and Err_Vdc as the input of the fuzzy controller to design the fuzzy PID control; A simulation model is built by fuzzy control to verify the reliability of the algorithm; S4. Then write the algorithm into the program to obtain the inverter speed Wr; S5. Determine whether the inverter speed Wr is greater than the inverter minimum speed Wr_Min; When the inverter speed Wr is greater than or equal to the inverter minimum speed Wr_Min, the inverter continues to run until it ends; When the power supplied by MPPT is insufficient to maintain the power consumed by the inverter due to changes in light conditions, the inverter speed Wr is actively reduced through the algorithm to reduce the power required by the inverter, ensuring that the bus voltage will not experience violent fluctuations and cause fault shutdown; When the power supplied by MPPT to the inverter continues to drop to the point where it cannot meet the power required for the inverter's minimum speed, that is, when the inverter speed Wr is less than the inverter's minimum speed Wr_Min, the inverter shuts down at the minimum speed and does not bring a large impact current to the inverter hardware.

2. A frequency converter control method for a photovoltaic MPPT panel according to claim 1, characterized in that: The step S3 specifically includes: S3.1 First, the system transfer function is obtained as The fuzzy PID controller is designed by MATLAB. Through the FUZZY editor, the input values ​​are Ave_Vdc and Err_Vdc, and the output values ​​are Kp, Ki, and Kd. The input and output both use the triangular membership function trimf, as shown in Formula 1. Among them, the domain of Ave_Vdc and Err_Vdc is [-6, 6], the domain of KP is [2, 5], the domain of Ki is [1, 3], and the domain of Kd is [7, 19]; S3.2 Then, edit the fuzzy rules according to the fuzzy table of proportional parameter P in Table 1, the fuzzy table of integral parameter i in Table 2, and the fuzzy table of calculus parameter d in Table 3; Table 1 Table 2 Table 3 In Tables 1, 2 and 3, NL means negative large, NM means negative medium, NS means negative small, ZE means zero, PS means positive small, PM means positive medium, and PB means positive large; The S3.3 program provides the value of the maximum membership output to resolve the fuzziness; Select the element with the largest membership in the fuzzy set of the inference result as the output value, that is, V0 = maxμ v (v); If there is more than one output value corresponding to the maximum membership in the output domain V, then the average value of the output with the maximum membership is taken, that is, v i =max(μ u (v)); S3.4 Then, a simulation model is built through simulink to verify the reliability of the algorithm; S3.5 From the simulation results, it can be seen that when the input power of the MPPT photovoltaic panel changes, the inverter power adjusts the speed at a faster speed to ensure that the power consumption basically follows the photovoltaic supply power to ensure operational stability.

3. An information data processing terminal for implementing the inverter control method for a photovoltaic MPPT panel as described in any one of claims 1 to 2.

4. A computer-readable storage medium for storing a computer program, characterized in that: When the computer program is called by the processor, the inverter control method for a photovoltaic MPPT panel described in any one of claims 1 to 2 is implemented.

5. An air conditioner, comprising a processor and a memory, wherein the memory is used to store a computer program, characterized in that: When the computer program is called by the processor, the inverter control method for a photovoltaic MPPT panel according to any one of claims 1 to 2 is implemented.

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