Maximum power point tracking method and related device

Abstract

The invention is suitable for the technical field of photovoltaic power generation, provides a maximum power point tracking method applied to a photovoltaic solar power generation system equipped with a 3P3Z compensator and a related device, and realizes rapid and stable tracking of the maximum power point of the photovoltaic solar power generation system. The method mainly comprises the steps of obtaining an output voltage and an output current of a photovoltaic matrix of a photovoltaic power generation system; generating a voltage reference value by using a preset maximum power point tracking algorithm based on the output voltage and the output current; calculating a voltage difference between the voltage reference value and the output voltage; inputting the voltage difference into a 3P3Z compensator for operation to obtain a current reference value; calculating a current difference between the current reference value and the output current; the current difference is input into a proportional-integral controller for operation, and a control signal is generated; generating a PWM waveform according to the control signal; and driving the DC-DC converter to output target power to the load through the PWM waveform.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic power generation technology, and in particular relates to a maximum power point tracking method and related apparatus for photovoltaic solar power generation systems equipped with 3P3Z compensators. Background Technology

[0002] Maximum power point tracking (MPPT) is primarily used in photovoltaic (PV) solar power generation to maximize the power output of the PV array under various conditions. The power generation process of a PV system is intricately influenced by factors such as ambient temperature and total circuit resistance, resulting in a non-linear relationship in its output efficiency, which can be represented by a current-voltage characteristic curve. MPPT aims to sample the output of the PV system and maintain maximum power output under any environmental conditions. MPPT equipment is typically integrated into power conversion systems, including voltage or current conversion, filtering, and driving of loads such as the grid, batteries, or motors. The power at the maximum power point (Pmpp) is the product of the voltage (Vmpp) and current (Impp) at the maximum power point.

[0003] The output characteristics of photovoltaic (PV) solar power generation systems are nonlinear, and their maximum power point (MPP) drifts with changes in external conditions such as light intensity and ambient temperature. To ensure that PV solar power generation systems consistently output maximum power, maximum power point tracking (MPP) technology is crucial. Traditional MPP algorithms, such as the incremental conductance method and the perturbation-observation method, suffer from a trade-off between tracking speed and steady-state accuracy: a large tracking step size results in a fast response but large oscillations, while a small step size results in small oscillations but a slow response. Furthermore, when light intensity changes rapidly (e.g., when clouds pass by), these traditional MPP algorithms are prone to misjudging the maximum power point, leading to power loss. Summary of the Invention

[0004] The purpose of this application is to provide a maximum power point tracking method and related apparatus, which can be applied to a photovoltaic solar power generation system equipped with a 3P3Z compensator to achieve fast and stable tracking of the maximum power point of the photovoltaic solar power generation system.

[0005] In a first aspect, this application provides a maximum power point tracking method, applied to a photovoltaic solar power generation system equipped with a 3P3Z compensator, comprising: Obtain the output voltage of the photovoltaic matrix of the photovoltaic power generation system. and output current ; Based on the output voltage and the output current A voltage reference value is generated using a preset maximum power point tracking algorithm. ; Calculate the voltage reference value With the output voltage voltage difference ; The voltage difference The current reference value is obtained by inputting the 3P3Z compensator into the circuit. ; Calculate the current reference value With the output current Current difference ; The current difference The input proportional-integral controller performs calculations to generate control signals; A PWM waveform is generated based on the control signal; The DC-DC converter is driven by the PWM waveform to output the target power to the load.

[0006] Optionally, the output voltage of the photovoltaic matrix of the photovoltaic power generation system is obtained. and output current include: The output voltage of the photovoltaic matrix of the photovoltaic power generation system is obtained in real time using a circuit. and output current .

[0007] Optionally, based on the output voltage and the output current A voltage reference value is generated using a preset maximum power point tracking algorithm. include: Calculate the output voltage and the output current Actual output power ; The actual output power is determined by using a preset power-voltage curve. Corresponding voltage reference value .

[0008] Optionally, the preset maximum power point tracking algorithm is the conductance increment method.

[0009] Optionally, the transfer function of the 3P3Z compensator is represented in the digital domain as follows:

[0010] Wherein, K represents the gain; Represents a complex variable; The The above The above These represent the three zero points of the 3P3Z compensator; The The above The above These represent the three poles of the 3P3Z compensator.

[0011] Optionally, the transfer function of the proportional-integral controller is represented in the digital domain as follows:

[0012] Among them, the Indicates the proportional gain, the Represents the integral gain, the This represents a Laplace variable.

[0013] Secondly, this application provides a maximum power point tracking device for use in a photovoltaic solar power generation system equipped with a 3P3Z compensator, comprising: The acquisition unit is used to acquire the output voltage of the photovoltaic matrix of the photovoltaic power generation system. and output current ; A generation unit, used for generating based on the output voltage and the output current A voltage reference value is generated using a preset maximum power point tracking algorithm. ; A calculation unit is used to calculate the voltage reference value. With the output voltage voltage difference ; The arithmetic unit is used to process the voltage difference. The current reference value is obtained by inputting the 3P3Z compensator into the circuit. ; The calculation unit is also used to calculate the current reference value. With the output current Current difference ; The arithmetic unit is also used to process the current difference. The input proportional-integral controller performs calculations to generate control signals; The generation unit is further configured to generate a PWM waveform based on the control signal; The output unit is used to drive the DC-DC converter to output the target power to the load through the PWM waveform.

[0014] Optionally, the acquisition unit acquires the output voltage of the photovoltaic matrix of the photovoltaic power generation system. and output current When, specifically used for: The output voltage of the photovoltaic matrix of the photovoltaic power generation system is obtained in real time using a circuit. and output current .

[0015] Optionally, the generation unit is based on the output voltage. and the output current A voltage reference value is generated using a preset maximum power point tracking algorithm. When, specifically used for: Calculate the output voltage and the output current Actual output power ; The actual output power is determined by using a preset power-voltage curve. Corresponding voltage reference value .

[0016] Optionally, the preset maximum power point tracking algorithm is the conductance increment method.

[0017] Optionally, the transfer function of the 3P3Z compensator is represented in the digital domain as follows:

[0018] Wherein, K represents the gain; Represents a complex variable; The The above The above These represent the three zero points of the 3P3Z compensator; The The above The above These represent the three poles of the 3P3Z compensator.

[0019] Optionally, the transfer function of the proportional-integral controller is represented in the digital domain as follows:

[0020] Among them, the Indicates the proportional gain, the Represents the integral gain, the This represents a Laplace variable.

[0021] Thirdly, this application provides a computer device, including: a processor, a memory, and a bus; The processor is connected to the memory via a bus; the memory stores a program. When the processor executes the program stored in the memory, it implements the maximum power point tracking method described in any one of the first aspects above.

[0022] Fourthly, this application provides a computer storage medium storing instructions that, when executed on a computer, cause the computer to perform the maximum power point tracking method described in any one of the first aspects.

[0023] Fifthly, this application provides a computer program product that, when executed on a computer, causes the computer to perform the maximum power point tracking method described in any one of the first aspects above.

[0024] As can be seen from the above technical solutions, the embodiments of this application have the following advantages: This embodiment applies the maximum power point tracking method to a photovoltaic solar power generation system equipped with a 3P3Z compensator, by obtaining the output voltage of the photovoltaic matrix of the photovoltaic power generation system. and output current Based on the output voltage and output current A voltage reference value is generated using a preset maximum power point tracking algorithm. Then calculate the voltage reference value. With the output voltage voltage difference ; to voltage difference The current reference value is obtained by inputting the 3P3Z compensator into the circuit. ; Calculate the reference value of the current With output current Current difference ; to change the current difference The input proportional-integral controller performs calculations to generate control signals; based on the control signals, a PWM waveform is generated; the PWM waveform drives the DC-DC converter to output the target power to the load. By introducing three zeros through the 3P3Z controller, the poles of the controlled object (photovoltaic power generation system, DC-DC converter) can be canceled more flexibly. This greatly expands the bandwidth of the voltage loop while ensuring the stability of the photovoltaic power generation system, enabling the photovoltaic power generation system to quickly track the movement of the maximum power point and reduce power loss caused by sudden environmental changes. Attached Figure Description

[0025] Figure 1 This is a schematic flowchart of an embodiment of the maximum power point tracking method of this application; Figure 2This is a schematic diagram of one embodiment of the maximum power point tracking device of this application; Figure 3 This is a schematic diagram of the structure of one embodiment of the computer device of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] Maximum power point tracking (MPPT) is primarily used in photovoltaic (PV) solar power generation to maximize the power output of the PV array under various conditions. The power generation process of a PV system has complex relationships with ambient temperature, total circuit resistance, and other factors, resulting in a non-linear relationship in its output efficiency, which can be represented by a current-voltage characteristic curve. MPPT aims to sample the output of the PV system and maintain maximum power output under any environmental conditions. MPPT equipment is typically integrated into power conversion devices, including voltage or current conversion, filtering, and driving loads such as the grid, batteries, or motors. The power at the maximum power point (Pmpp) is the product of the voltage (Vmpp) and current (Impp) at the maximum power point. The output characteristics of a PV system are non-linear, and its maximum power point drifts with changes in external conditions such as light intensity and ambient temperature. MPPT technology is crucial to ensuring that the PV system consistently outputs maximum power. Traditional maximum power point tracking (MPPT) algorithms, such as the incremental conductance method and the perturbation-observation method, suffer from a trade-off between tracking speed and steady-state accuracy: a large tracking step size results in a fast response but large oscillations, while a small tracking step size results in small oscillations but a slow response. Furthermore, when illumination changes rapidly (such as when clouds pass by), these traditional MPPT algorithms are prone to misidentifying the maximum power point, leading to power loss.

[0028] With the development of digital signal processors, maximum power point tracking (MPPT) methods based on closed-loop control have gained increasing attention. Among these, the voltage-current dual-loop control structure is a common approach, where the outer loop handles the voltage input for MPPT, and the inner loop handles the current input for rapid MPPT. Currently, both the inner and outer loops generally employ traditional proportional-integral (PI) controllers. However, for nonlinear and time-varying systems like photovoltaic solar power generation systems, the control performance of PI controllers is relatively limited, as specifically demonstrated below: 1. Conflict between response speed and overshoot: Increasing the proportional coefficient to improve response speed will lead to an increase in overshoot, and may even cause oscillations, affecting the stability of the system; 2. Limited disturbance rejection capability: When faced with drastic changes in light intensity and temperature, the proportional-integral controller struggles to achieve rapid and stable adjustment, resulting in significant power loss during dynamic processes. 3. Poor adaptability to complex objects: The second-order characteristic of the proportional-integral controller (one pole located at the origin) limits the control accuracy and bandwidth for high-order, nonlinear controlled objects such as photovoltaic power generation.

[0029] To address the aforementioned technical issues, this embodiment introduces a high-performance compensator to resolve the contradiction between dynamic response speed and steady-state control accuracy in traditional solar photovoltaic power generation systems employing a voltage-current dual-loop control structure, thereby significantly improving the energy capture efficiency of solar photovoltaic power generation systems in complex environments.

[0030] It should be noted that the high-performance compensator in this embodiment is a 3P3Z compensator (a three-pole, three-zero compensator, also known as a 3P3Z controller). In this embodiment, the 3P3Z compensator is used as the voltage outer loop controller of a voltage-current dual-loop control structure. The solar photovoltaic power generation system in this embodiment includes a photovoltaic array, a voltage-current dual-loop control structure equipped with a 3P3Z compensator, a DC-DC converter (e.g., Boost, Buck, Buck-Boost, etc.), and a load. The voltage-current dual-loop control structure equipped with a 3P3Z compensator includes: a sampling circuit, a voltage outer loop controller, a current inner loop controller, and a PWM (Pulse-Width Modulation) drive circuit.

[0031] Please see Figure 1 An embodiment of the maximum power point tracking method of this application is applied to a photovoltaic solar power generation system equipped with a 3P3Z compensator, including: 101. Obtain the output voltage and output current of the photovoltaic matrix in the photovoltaic power generation system.

[0032] This step involves using a circuit to obtain the output voltage of the photovoltaic matrix in the photovoltaic power generation system in real time. and output current .

[0033] 102. Based on the output voltage and output current, a voltage reference value is generated using a preset maximum power point tracking algorithm.

[0034] This step calculates the output voltage. and output current Actual output power The actual output power is then determined from the preset power-voltage curve. Corresponding voltage reference value Of course, this step can also use the incremental conductance method to generate a voltage reference value. Here, based on the output voltage... and output current Generate voltage reference value The method is not limited.

[0035] 103. Calculate the voltage difference between the voltage reference value and the output voltage.

[0036] Voltage reference value With output voltage Compare and calculate voltage reference values. With output voltage voltage difference .

[0037] 104. Input the voltage difference into the 3P3Z compensator for calculation to obtain the current reference value.

[0038] In this embodiment, the voltage outer loop controller uses a three-pole, three-zero compensator, i.e., a 3P3Z compensator, as the controller to control the voltage difference. The current reference value is obtained by inputting the 3P3Z compensator into the circuit. The transfer function of the 3P3Z compensator in this step is expressed in the digital domain as follows:

[0039] Wherein, K represents the gain; Represents a complex variable; the The above The above These represent the three zero points of the 3P3Z compensator; The above The above These represent the three poles of the 3P3Z compensator. By properly configuring the positions of the three poles and three zeros, the outer loop controller can achieve high bandwidth for fast tracking, while also having high phase margin to ensure stability, and providing sufficient attenuation at specific frequency points (such as near the switching frequency) to suppress noise.

[0040] 105. Calculate the current difference between the current reference value and the output current.

[0041] The current reference value is obtained in step 104. Next, this step will use the current reference value. With output current The reference current value was calculated by comparing the values. With the output current Current difference .

[0042] 106. Input the current difference into the proportional-integral controller for calculation and generate a control signal.

[0043] The transfer function of the proportional-integral controller in this step is expressed in the digital domain as follows:

[0044] Among them, the Indicates the proportional gain, the Represents the integral gain, the This represents the Laplace variable. The inner-loop current controller is typically approximated as a first-order inertial element. A proportional-integral controller is sufficient to achieve zero steady-state error tracking, and its computational complexity is low, which is beneficial for improving the system's switching frequency and response speed. Therefore, this step will use the current difference... The input proportional-integral controller performs calculations to generate control signals.

[0045] 107. Generate PWM waveform based on control signal.

[0046] The output signal of the current inner loop controller is compared with the carrier wave, and a PWM waveform with a variable duty cycle is generated by the PWM drive circuit.

[0047] 108. Drive the DC-DC converter to output the target power to the load using a PWM waveform.

[0048] The PWM waveform is used to drive the power switches in the DC-DC converter, ultimately achieving precise control of the photovoltaic power generation system's operating point and outputting the target power to the load. This dual-loop structure senses the system state through a sampling circuit. The outer voltage loop (3P3Z) is responsible for the precise stabilization of the macroscopic voltage target, while the inner current loop (PI) is responsible for the rapid tracking of the microscopic current. The PWM drive circuit is responsible for converting the digital control signal into actual power switching actions. This cascaded design fully leverages the advantages of the 3P3Z compensator in handling complex nonlinear objects and the simplicity and speed of the PI controller, achieving high-performance power conversion and maximum power point tracking.

[0049] This implementation features extremely fast dynamic response: the 3P3Z controller, through the introduction of three zeros, can more flexibly cancel the poles of the controlled object (photovoltaic power generation system), thereby greatly expanding the bandwidth of the voltage loop while ensuring the stability of the photovoltaic power generation system. This allows the system to quickly track the movement of the maximum power point and reduce power loss caused by sudden environmental changes. This implementation also features high overshoot and strong stability: through the reasonable configuration of the three poles, it can provide rapid gain attenuation in the high-frequency band, effectively suppressing oscillations and overshoot. Compared to a proportional-integral controller, the 3P3Z can achieve superior dynamic performance, i.e., while responding quickly... It maintains stability without violent oscillations; this implementation has optimized anti-interference performance: the 3P3Z controller can be precisely compensated for specific interference frequencies (such as input voltage ripple and switching noise), providing deeper attenuation, making the system less sensitive to noise and disturbances, and the steady-state output power smoother; this implementation achieves a balance between computational complexity and performance: it innovatively applies the complex 3P3Z controller to the voltage outer loop, which has the greatest impact on the performance of the photovoltaic power generation system, while the current inner loop still uses a simple and efficient PI controller. This architecture achieves a qualitative leap in the overall performance of the system without excessively increasing the computational burden on the digital processor.

[0050] The above embodiments describe the application of the maximum power point tracking method of this application to a photovoltaic solar power generation system equipped with a 3P3Z compensator. The following describes the application of the maximum power point tracking device of this application to a photovoltaic solar power generation system equipped with a 3P3Z compensator. Please refer to [link to documentation]. Figure 2 One embodiment of the maximum power point tracking device of this application includes: Acquisition unit 201 is used to acquire the output voltage of the photovoltaic matrix of the photovoltaic power generation system. and output current ; Generation unit 202, used for generating based on the output voltage and the output current A voltage reference value is generated using a preset maximum power point tracking algorithm. ; Calculation unit 203 is used to calculate the voltage reference value. With the output voltage voltage difference ; The arithmetic unit 204 is used to process the voltage difference. The current reference value is obtained by inputting the 3P3Z compensator into the circuit. ; The calculation unit 203 is also used to calculate the current reference value. With the output current Current difference ; The arithmetic unit 204 is also used to process the current difference. The input proportional-integral controller performs calculations to generate control signals; The generation unit 202 is further configured to generate a PWM waveform based on the control signal; The output unit 205 is used to drive the DC-DC converter to output the target power to the load through the PWM waveform.

[0051] Optionally, the acquisition unit 201 acquires the output voltage of the photovoltaic matrix of the photovoltaic power generation system. and output current When, specifically used for: The output voltage of the photovoltaic matrix of the photovoltaic power generation system is obtained in real time using a circuit. and output current .

[0052] Optionally, the generation unit 202 is based on the output voltage. and the output current A voltage reference value is generated using a preset maximum power point tracking algorithm. When, specifically used for: Calculate the output voltage and the output current Actual output power ; The actual output power is determined by using a preset power-voltage curve. Corresponding voltage reference value .

[0053] Optionally, the preset maximum power point tracking algorithm is the conductance increment method.

[0054] Optionally, the transfer function of the 3P3Z compensator is represented in the digital domain as follows:

[0055] Wherein, K represents the gain; Represents a complex variable; The The above The above These represent the three zero points of the 3P3Z compensator; The The above The above These represent the three poles of the 3P3Z compensator.

[0056] Optionally, the transfer function of the proportional-integral controller is represented in the digital domain as follows:

[0057] Among them, the Indicates the proportional gain, the Represents the integral gain, the This represents a Laplace variable.

[0058] The operation performed by the maximum power point tracking device in this application is the same as described above. Figure 1 The operations described in the embodiments are similar, and repeated parts will not be repeated here.

[0059] The computer device in the embodiments of this application is described below. Please refer to [link / reference]. Figure 3 One embodiment of the computer device in this application includes: The computer device 300 may include one or more central processing units (CPUs) 301 and memory 302, wherein the memory 302 stores one or more application programs or data. The memory 302 is volatile or persistent storage. The program stored in the memory 302 may include one or more modules, each module including a series of instruction operations on the computer device. Furthermore, the processor 301 may be configured to communicate with the memory 302 and execute the series of instruction operations stored in the memory 302 on the computer device 300. The computer device 300 may also include one or more operating systems, such as Harmony OS, Windows Server, Mac OS, Unix, Linux, FreeBSD, etc. The processor 301 can execute the aforementioned... Figure 1 The specific operations performed in the embodiments will not be described in detail here.

[0060] In the several embodiments provided in this application, those skilled in the art should understand that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0061] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0062] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A maximum power point tracking method, characterized in that, Applied to photovoltaic solar power generation systems equipped with 3P3Z compensators, including: Obtain the output voltage of the photovoltaic matrix of the photovoltaic power generation system. and output current ; Based on the output voltage and the output current A voltage reference value is generated using a preset maximum power point tracking algorithm. ; Calculate the voltage reference value With the output voltage voltage difference ; The voltage difference The current reference value is obtained by inputting the 3P3Z compensator into the circuit. ; Calculate the current reference value With the output current Current difference ; The current difference The input proportional-integral controller performs calculations to generate control signals; A PWM waveform is generated based on the control signal; The DC-DC converter is driven by the PWM waveform to output the target power to the load.

2. The maximum power point tracking method according to claim 1, characterized in that, Obtain the output voltage of the photovoltaic matrix of the photovoltaic power generation system. and output current include: The output voltage of the photovoltaic matrix of the photovoltaic power generation system is obtained in real time using a circuit. and output current .

3. The maximum power point tracking method according to claim 1, characterized in that, Based on the output voltage and the output current A voltage reference value is generated using a preset maximum power point tracking algorithm. include: Calculate the output voltage and the output current Actual output power ; The actual output power is determined by using a preset power-voltage curve. Corresponding voltage reference value .

4. The maximum power point tracking method according to claim 1, characterized in that, The preset maximum power point tracking algorithm is the conductance increment method.

5. The maximum power point tracking method according to claim 1, characterized in that, The transfer function of the 3P3Z compensator is expressed in the digital domain as follows: Wherein, K represents the gain; Represents a complex variable; The The above The above These represent the three zero points of the 3P3Z compensator; The The above The above These represent the three poles of the 3P3Z compensator.

6. The maximum power point tracking method according to claim 1, characterized in that, The transfer function of the proportional-integral controller is expressed in the digital domain as follows: Among them, the Indicates the proportional gain, the Represents the integral gain, the This represents a Laplace variable.

7. A maximum power point tracking device, characterized in that, Applied to photovoltaic solar power generation systems equipped with 3P3Z compensators, including: The acquisition unit is used to acquire the output voltage of the photovoltaic matrix of the photovoltaic power generation system. and output current ; A generation unit, used for generating based on the output voltage and the output current A voltage reference value is generated using a preset maximum power point tracking algorithm. ; A calculation unit is used to calculate the voltage reference value. With the output voltage voltage difference ; The arithmetic unit is used to process the voltage difference. The current reference value is obtained by inputting the 3P3Z compensator into the circuit. ; The calculation unit is also used to calculate the current reference value. With the output current Current difference ; The arithmetic unit is also used to process the current difference. The input proportional-integral controller performs calculations to generate control signals; The generation unit is further configured to generate a PWM waveform based on the control signal; The output unit is used to drive the DC-DC converter to output the target power to the load through the PWM waveform.

8. A computer device, characterized in that, include: Processor, memory, bus; The processor is connected to the memory via a bus; The memory stores a program; When the processor executes the program stored in the memory, it implements the maximum power point tracking method according to any one of claims 1 to 6.

9. A computer storage medium, characterized in that, The computer storage medium stores instructions that, when executed on the computer, cause the computer to perform the maximum power point tracking method according to any one of claims 1 to 6.

10. A computer program product, characterized in that, When the computer program product is executed on a computer, it causes the computer to perform the string maximum power point tracking method according to any one of claims 1 to 6.

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