Hybrid renewable energy system, control method and charging system

Abstract

The invention belongs to the technical field of power systems, and discloses a hybrid renewable energy system, a control method and a charging system.The hybrid renewable energy system comprises a bidirectional Zeta converter, an inverter, a photovoltaic power source and a wind power source; the bidirectional Zeta converter comprises a first switch tube, a second switch tube, a first capacitor, a second capacitor, a third capacitor, a filter capacitor, a first inductor, a second inductor and a diode. The inverter comprises an inverter first switch tube, an inverter second switch tube, an inverter third switch tube, an inverter fourth switch tube, an inverter fifth switch tube and an inverter sixth switch tube; the source electrode of the fifth switch tube of the inverter is connected with the drain electrode of the sixth switch tube of the inverter; and the inverter is connected with a power grid. According to the invention, the efficiency of the photovoltaic system is obviously improved, so that photovoltaic and wind power generation systems are integrated into a power grid, and continuous and reliable power supply is provided for charging of the electric vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems and relates to a hybrid renewable energy system, a control method and a charging system. Background Art

[0002] Photovoltaic power generation systems convert light energy into electrical energy based on the photovoltaic effect. When light acts on semiconductors and metal components, electrons drift and form a potential difference, which in turn generates voltage. In contrast, stand-alone wind power generation systems generate electricity by rotating generator blades driven by wind energy, and their output is alternating current. Although both systems face challenges such as susceptibility to weather and environmental conditions, and wind power generation also faces high investment costs and potential ecological damage, they each have unique advantages. It is worth noting that under most natural conditions, summer is characterized by abundant sunlight and scarce wind energy, while winter is characterized by abundant wind energy and reduced sunlight. Therefore, considering my country's environmental characteristics, the advantages of photovoltaic and wind power generation can be combined to achieve the rational allocation and efficient use of renewable energy.

[0003] Chinese Patent Publication No. CN111510008A, titled "A Photovoltaic Inverter and Control Method Thereof," discloses a photovoltaic inverter comprising: photovoltaic modules, an intermediate capacitor, a first filter inductor, a second filter inductor, a third filter inductor, a first diode, a second diode, a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor; and a drive control circuit. The first, second, and third filter inductors operate only during half of the power frequency cycle; the first and second switching transistors perform high-frequency switching during the negative and positive half cycles of the grid voltage, respectively; and the third and fourth switching transistors perform power frequency switching. This patent application fails to fully utilize both wind and photovoltaic power generation systems. Summary of the Invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a hybrid renewable energy system, control method and charging system, which significantly improves the efficiency of the photovoltaic system by increasing the voltage level through a high-gain bidirectional Zeta converter, thereby integrating photovoltaic and wind power generation systems into the power grid and providing a continuous and reliable power supply for charging electric vehicles.

[0005] To achieve the above object, the technical solution adopted by the present invention is: In a first aspect, the present invention provides a hybrid renewable energy system, comprising: a bidirectional Zeta converter, an inverter, a photovoltaic power source, and a wind power source; the bidirectional Zeta converter comprises a first switch tube, a second switch tube, a first capacitor, a second capacitor, a third capacitor, a filter capacitor, a first inductor, a second inductor, and a diode; the inverter comprises a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube, and a sixth switch tube; the positive electrode of the photovoltaic power source is connected to the drain of the first switch tube, and the source of the first switch tube is connected to the first end of the first capacitor and the first end of the first inductor; the first capacitor The second end of the second inductor is connected to the first end of the second inductor, the first end of the second capacitor and the drain of the second switch tube; the second end of the second inductor is connected to the anode of the diode and the first end of the third capacitor, the cathode of the diode is connected to the second end of the second capacitor, the first end of the filter capacitor, the positive electrode of the wind power source, the drain of the first switch tube of the inverter, the drain of the third switch tube of the inverter and the drain of the fifth switch tube of the inverter; the source of the first switch tube of the inverter is connected to the drain of the second switch tube of the inverter; the drain of the third switch tube of the inverter is connected to the drain of the fourth switch tube of the inverter; the source of the fifth switch tube of the inverter is connected to the drain of the sixth switch tube of the inverter; and the inverter is connected to the power grid.

[0006] Optionally, the inverter also includes a first filter inductor, a second filter inductor, a third filter inductor, a first energy storage capacitor, a second energy storage capacitor and a third energy storage capacitor; the source of the first switch tube of the inverter is connected to the first end of the first filter inductor; the drain of the third switch tube of the inverter is connected to the first end of the second filter inductor; the source of the fifth switch tube of the inverter is connected to the first end of the third filter inductor; one end of the first energy storage capacitor is connected to the second end of the first filter inductor, and the other end is connected to the power grid; one end of the second energy storage capacitor is connected to the second end of the second filter inductor, and the other end is connected to the power grid; one end of the third energy storage capacitor is connected to the second end of the third filter inductor, and the other end is connected to the power grid.

[0007] Optionally, the negative electrode of the wind power source, the second end of the filter capacitor, the second end of the third capacitor, the source of the second switch tube and the second end of the first inductor, the source of the second switch tube of the inverter, the source of the fourth switch tube of the inverter, and the source of the sixth switch tube of the inverter are all connected to the negative electrode of the photovoltaic power source.

[0008] Optionally, both the first switching tube and the second switching tube are insulated gate bipolar transistors.

[0009] Optionally, the diode is a ROHM S0KG type silicon carbide Schottky diode.

[0010] In a second aspect, the present invention provides a method for using a hybrid renewable energy system, based on the hybrid renewable energy system, comprising the following steps: The DC power generated by the photovoltaic power source and the wind power generation system power source is input into the bidirectional Zeta converter; By alternately turning on the first switch tube and the second switch tube, the first inductor, the second inductor and the first capacitor, the second capacitor and the third capacitor are charged and discharged in stages to increase the input voltage; The boosted DC power is input into the three-phase inverter module, and the DC power is converted into AC power with the same frequency and phase as the power grid through PWM control of the first switch tube of the inverter, the second switch tube of the inverter, the third switch tube of the inverter, the fourth switch tube of the inverter, the fifth switch tube of the inverter, and the sixth switch tube of the inverter.

[0011] In a third aspect, the present invention provides a method for controlling a photovoltaic power source of a hybrid renewable energy system, based on the hybrid renewable energy system, comprising the following steps: In the initialization phase, the photovoltaic system parameters and environmental conditions are input, and a population search algorithm is used to generate a searcher population, where each individual represents a perturbation step length ΔU; The knowledge sharing of the objective function with the maximum power voltage difference at adjacent moments is carried out through fuzzy logic system; Assume that selfish behavior is the individual historical optimal direction, altruistic behavior is the global optimal direction, and proactive behavior is the historical change trend, and comprehensively update the search direction; The iterative process re-evaluates the population fitness according to the voltammetric equilibrium principle until convergence or the termination condition is reached; Output the optimal perturbation step size.

[0012] In a fourth aspect, the present invention provides a method for controlling a wind power source in a hybrid renewable energy system, based on the hybrid renewable energy system, comprising the following steps: Maximum power point tracking based on artificial fish school algorithm: Input wind power system parameters and initial algorithm configuration to generate an initial fish school, with each artificial fish corresponding to a candidate perturbation step size. By calculating the power difference ΔP at the current wind speed as the fitness value, the foraging, flocking, chasing or random walking behaviors are dynamically selected, and the perturbation step size is gradually updated; The foraging behavior adjusts the step direction according to the power change. The flocking and tail-chasing behaviors guide the fish to move to the adjacent optimal or global optimal position respectively. At the same time, the visual step joint coefficient ψ is introduced to balance the adaptive adjustment of the field of view and step length. The iterative optimization is performed until the power difference approaches zero or the maximum number of iterations is reached, and the optimal perturbation step size is finally output to achieve rapid tracking of the maximum power point.

[0013] In a fifth aspect, the present invention provides a charging system for an electric vehicle, comprising the aforementioned hybrid renewable energy system.

[0014] In a sixth aspect, the present invention provides a method for using a charging system for an electric vehicle, based on the aforementioned charging system for an electric vehicle, comprising the following steps: When charging electric vehicles, electricity generated by photovoltaic and wind power is used to charge the electric vehicle batteries; if renewable energy is insufficient, it switches to grid power supply; When the electric vehicle battery has excess energy, the battery energy is fed back to the grid through the reverse operation of the bidirectional Zeta converter and inverter.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention designs a hybrid renewable energy system, control method and charging system, which integrates photovoltaic and wind power generation systems into the power grid to provide a continuous and reliable power supply for charging electric vehicles.

[0016] This paper designs and implements a high-gain bidirectional Zeta converter, significantly improving photovoltaic system efficiency by boosting voltage levels. To optimize power extraction, the system employs a maximum power point tracking (MPPT) control strategy for photovoltaic power generation based on a crowd search algorithm and an artificial fish school algorithm for wind power generation system power output control, ensuring superior converter performance and maximum energy harvesting. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only schematic and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings: Figure 1 FIG. 4 is a circuit model of a high-gain bidirectional Zeta converter according to an embodiment of the present invention.

[0018] Figure 2 This is a flowchart of solving the optimal perturbation step size using the SOA algorithm according to an embodiment of the present invention.

[0019] Figure 3 This is an algorithm flow chart of the MPPT control strategy for a photovoltaic power generation system according to an embodiment of the present invention.

[0020] Figure 4 Flowchart of an artificial fish swarm algorithm according to an embodiment of the present invention.

[0021] Figure 5 This is an algorithm flow chart of the MPPT control strategy for a wind power generation system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0024] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0025] When an element is referred to as being "disposed on" another element, it may be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may also be an intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiments. If the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly tilted.

[0026] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures. In the description of the present invention, it should be understood that the terms "comprise" and "include" indicate the presence of the described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their combinations.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0028] The present invention will be described in detail below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, a hybrid renewable energy system of the present invention includes: a bidirectional Zeta converter, an inverter, a photovoltaic power source PV and a wind power source; the bidirectional Zeta converter includes a first switch tube S1, a second switch tube S2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a filter capacitor Co, a first inductor L1, a second inductor L2 and a diode D; the inverter includes a first switch tube T1, a second switch tube T2, a third switch tube T3, a fourth switch tube T4, a fifth switch tube T5 and a sixth switch tube T6; the positive electrode of the photovoltaic power source PV is connected to the drain of the first switch tube S1, and the source of the first switch tube S1 is connected to the first end of the first capacitor C1 and the first end of the first inductor L1; the first The second end of capacitor C1 is connected to the first end of the second inductor L2, the first end of the second capacitor C2, and the drain of the second switch S2; the second end of the second inductor L2 is connected to the anode of diode D and the first end of the third capacitor C3; the cathode of diode D is connected to the second end of the second capacitor C2, the first end of the filter capacitor Co, the positive electrode of the wind power source, the drain of the first switch T1 of the inverter, the drain of the third switch T3 of the inverter, and the drain of the fifth switch T5 of the inverter; the source of the first switch T1 of the inverter is connected to the drain of the second switch T2 of the inverter; the drain of the third switch T3 of the inverter is connected to the drain of the fourth switch T4 of the inverter; the source of the fifth switch T5 of the inverter is connected to the drain of the sixth switch T6 of the inverter; and the inverter is connected to the power grid.

[0030] This paper designs and implements a high-gain bidirectional Zeta converter, which significantly improves the efficiency of photovoltaic systems by boosting voltage levels. This allows for the integration of photovoltaic and wind power systems into the power grid, providing a continuous and reliable power supply for charging electric vehicles.

[0031] Example 1 like Figure 1Figure 2 shows a circuit model for a high-gain bidirectional Zeta converter suitable for electric vehicles. This converter boosts the voltage generated by photovoltaic panels. The electric vehicle battery is charged using the voltage generated by the photovoltaic panels. If the photovoltaic supply is insufficient, the electric vehicle battery can be supplemented by drawing power from the grid.

[0032] Photovoltaic power source PV, first switching tube S1, second switching tube S2, first capacitor C1, second capacitor C2, third capacitor C3, filter capacitor Co, first inductor L1, second inductor L2, diode D, first switching tube T1 of inverter, second switching tube T2 of inverter, third switching tube T3 of inverter, fourth switching tube T4 of inverter, fifth switching tube T5 of inverter, sixth switching tube T6 of inverter, first filter inductor LF1, second filter inductor LF2, third filter inductor LF3, first energy storage capacitor CF1, second energy storage capacitor CF2 and third filter inductor LF3; the positive electrode of photovoltaic power source PV is connected to the drain of first switching tube S1, the source of first switching tube S1 is connected to the first end of first capacitor C1 and the first end of first inductor L1; the second end of first capacitor C1 is connected to the first end of second inductor L2, the first end of second capacitor C2 and the drain of second switching tube S2; the second end of second inductor L2 is connected to the anode of diode D and third capacitor C3 The cathode of the diode D is connected to the second end of the second capacitor C2, the first end of the filter capacitor Co, the positive electrode of the wind power source, the drain of the first switch tube T1 of the inverter, the drain of the third switch tube T3 of the inverter and the drain of the fifth switch tube T5 of the inverter; the source of the first switch tube T1 of the inverter is connected to the drain of the second switch tube T2 of the inverter and the first end of the first filter inductor LF1; the drain of the third switch tube T3 of the inverter is connected to the drain of the fourth switch tube T4 of the inverter and the first end of the second filter inductor LF2; the source of the fifth switch tube T5 of the inverter is connected to the drain of the sixth switch tube T6 of the inverter and the first end of the third filter inductor LF3; one end of the first energy storage capacitor CF1 is connected to the second end of the first filter inductor LF1, and the other end is connected to the grid; one end of the second energy storage capacitor CF2 is connected to the second end of the second filter inductor LF2, and the other end is connected to the grid; one end of the third energy storage capacitor CF3 is connected to the second end of the third filter inductor LF3, and the other end is connected to the grid.

[0033] The DC power generated by photovoltaic (PV) and wind power generation systems is input into the Zeta converter as the initial power source. This can provide DC power input from renewable energy sources.

[0034] Boosting with a Zeta Converter: Using the high-gain bidirectional Zeta converter's two switching modes (alternating conduction of the first and second switches S1 and S2), the first and second inductors L1 and L2, as well as the first, second, and third capacitors C1, C2, and C3, are charged and discharged in stages, boosting the input voltage. This outputs a stable, high-voltage direct current (VDC) to meet the charging needs of electric vehicles.

[0035] The boosted DC power VDC is input into the three-phase inverter module, and the DC power is converted into AC power through PWM control of the first switch tube T1 of the inverter, the second switch tube T2 of the inverter, the third switch tube T3 of the inverter, the fourth switch tube T4 of the inverter, the fifth switch tube T5 of the inverter, and the sixth switch tube T6 of the inverter.

[0036] Generates AC power with the same frequency and phase as the power grid, making it easy to connect to the grid or use by loads.

[0037] The inverter AC power is filtered by the first filter inductor LF1, the second filter inductor LF2, the third filter inductor LF3, the first energy storage capacitor CF1, the second energy storage capacitor CF2, and the third energy storage capacitor CF3 to eliminate high-frequency noise before being connected to the grid. The resulting smooth AC power is synchronized with the grid and replenishes energy.

[0038] Optionally, the first switch tube S1 and the second switch tube S2 are both Infineon IKW75N65EH5 insulated gate bipolar transistors (IGBTs) with a withstand voltage of 1200V and excellent high-frequency characteristics.

[0039] Optionally, the first switching tube T1 of the inverter, the second switching tube T2 of the inverter, the third switching tube T3 of the inverter, the fourth switching tube T4 of the inverter, the fifth switching tube T5 of the inverter and the sixth switching tube T6 of the inverter all use Infineon IKW75N60T insulated gate bipolar transistors with a withstand voltage of 600V and low cost.

[0040] Optionally, the diode D adopts a ROHM SCS220KG silicon carbide Schottky diode with a short reverse recovery time and a withstand voltage of 1200V.

[0041] Optionally, the filter capacitor Co adopts a TDK B32678 film capacitor with a withstand voltage of 1000V and low ESR (Equivalent Series Resistance).

[0042] Optionally, the first capacitor C1 , the second capacitor C2 , the third capacitor C3 , the first energy storage capacitor CF1 , the second energy storage capacitor CF2 , and the third energy storage capacitor CF3 are all Nichicon LGN electrolytic capacitors with a withstand voltage of 450V and a capacity of 100μF to 470μF.

[0043] Optionally, the first inductor L1 and the second inductor L2 are both Würth Elektronik WE-HCI type ferrite core inductors with an inductance value of 200 μH-1 mH.

[0044] Optionally, the filter inductor LF uses a Murata DLW43SH common-mode choke inductor to suppress common-mode noise.

[0045] Example 2 A photovoltaic power supply control method according to this embodiment includes the following steps: The control method of photovoltaic power supply uses the Seeker Optimization Algorithm (SOA) to optimize the Maximum Power Point Tracking (MPPT): During the initialization phase, PV system parameters (open-circuit voltage, short-circuit current, etc.) and environmental conditions (light intensity, temperature) are input to generate a population of searchers, each representing a perturbation step size ΔU. A fuzzy logic system shares knowledge of the objective function (maximum power voltage difference between adjacent moments). The search direction is updated by combining self-interested behavior (individual historical optimal direction), altruistic behavior (global optimal direction), and predictive behavior (historical trend of change). During the iteration process, the population fitness is reassessed based on the principle of volt-ampere balance until convergence or a termination criterion is met. Ultimately, the optimal perturbation step size is output, ensuring efficient energy extraction from the PV system in complex environments.

[0046] Example 3 A wind power control method according to this embodiment includes the following steps: The wind turbine control method uses the Artificial Fish Swarm Algorithm (AFSA) to achieve maximum power point tracking. Wind turbine system parameters (such as blade radius, air density, and generator characteristics) and initial algorithm configuration (such as the number of artificial fish, step size, and field of view) are input to generate an initial fish swarm. Each artificial fish corresponds to a candidate perturbation step size. The power difference ΔP at the current wind speed is calculated as a fitness value. Foraging, swarming, chasing, or random swimming behaviors are dynamically selected, and the perturbation step size is gradually updated. Foraging behavior adjusts the step size direction based on power fluctuations. Swarming and chasing behaviors guide the fish swarm toward the nearest optimal or global optimal position, respectively. A joint view step coefficient ψ is introduced to balance the adaptive adjustment of field of view and step size. Iterative optimization is performed until the power difference approaches zero or the maximum number of iterations is reached. Finally, the optimal perturbation step size is output, achieving rapid maximum power point tracking.

[0047] When charging electric vehicles, photovoltaic and wind power generation are prioritized for charging the battery. If renewable energy is insufficient, the system automatically switches to grid power, ensuring a continuous and reliable power supply for electric vehicles.

[0048] When the electric vehicle battery has excess energy, the Zeta converter and inverter modules operate in reverse to feed the battery energy back to the grid, achieving a bidirectional flow of energy and improving system energy efficiency.

[0049] Example 4 In this embodiment, photovoltaic or wind power generation is used as input, and the DC power generated by the photovoltaic and wind power generation systems is input into the Zeta converter as the initial power source, providing DC power input from renewable energy.

[0050] Through the two switching modes of the high-gain bidirectional Zeta converter, the first switch tube S1 and the second switch tube S2 are alternately turned on, and the first filter inductor LF1, the second filter inductor LF2, the third filter inductor LF3, the first capacitor C1, the second capacitor C2 and the third capacitor C3 are charged and discharged in stages to increase the input voltage.

[0051] Result: Output stable high-voltage direct current (VDC) to meet the charging needs of electric vehicles.

[0052] The boosted direct current (VDC) is input into the three-phase inverter module, and the direct current is converted into alternating current through PWM control of the first switch tube T1, the second switch tube T2, the third switch tube T3, the fourth switch tube T4, the fifth switch tube T5 and the sixth switch tube T6 of the inverter.

[0053] Generates AC power with the same frequency and phase as the power grid, making it easy to connect to the grid or use by loads.

[0054] The inverted AC power is filtered by the first filter inductor LF1, the second filter inductor LF2, the third filter inductor LF3 and the first energy storage capacitor CF1, the second energy storage capacitor CF2 and the third energy storage capacitor CF3 to eliminate high-frequency noise and then connected to the power grid.

[0055] Outputs smooth AC power, synchronizes with the grid and replenishes energy.

[0056] Prioritizes using photovoltaic or wind power to charge electric vehicle batteries; if renewable energy is insufficient, it automatically switches to grid power, ensuring a continuous and reliable power supply for electric vehicles.

[0057] When the electric vehicle battery has surplus energy, the Zeta converter and inverter module operate in reverse to feed the battery power back to the grid, achieving a two-way flow of energy and improving system energy efficiency.

[0058] Example 5 like Figure 1 As shown in Figure 1, the converter is designed to provide an output voltage higher than the input voltage and is capable of operating in continuous conduction mode under various load conditions. In this mode, the converter undergoes two switching modes within a single switching cycle Ts: In the first phase, the second switch S2 and the diode D are in the off state, while the first switch S1 is in the on state. First, it charges the first inductor L1 through the main first switch S1. Second, it charges the second inductor L2 and the second capacitor C2, forming a loop with the first capacitor C1. It also charges the third filter inductor LF3 and the filter capacitor Co through the second capacitor C2 and the third capacitor C3, forming another loop to power the load. Figure 1 The configuration shown. Throughout the cycle, the currents in the inductors increase linearly. Simultaneously, the first and third capacitors C1 and C3 discharge, causing the voltage across them to drop slightly, while capacitor C2 and filter capacitor Co charge, causing the voltage to rise. During this phase, the voltage equations across the first, second, and third filter inductors LF1, LF2, and LF3 can be expressed as:

[0059]

[0060]

[0061] In the second phase, the second switch S2 and the diode D are turned on, while the first switch S1 is turned off. Figure 1In the configuration shown, the first inductor L1 partially charges the first capacitor C1 through the first switch S1, and also charges the third capacitor C3 and the second capacitor C2. Simultaneously, the second inductor L2 charges the third capacitor C3 through the diode D, and the second capacitor C2 supplies power to the load through the diode D, the third filter inductor LF3, and the capacitor Co. Throughout this phase, the first capacitor C1 and the third capacitor C3 charge, causing their voltages to increase slightly. Conversely, the second capacitor C2 and the filter capacitor Co discharge, causing their voltages to decrease slightly. At the same time, i L1 、i L2 and i L3 All decrease linearly. The related voltage equation is derived as follows:

[0062] By considering the operating principle analysis and applying the volt-ampere balance principle to the first inductors L1, L2 and L3,

[0063]

[0064]

[0065] About rewriting expressions

[0066] Therefore, the voltage gain M is determined by calculating using the specified equation

[0067] The voltage stress across the diode and switch is expressed as:

[0068] In order to simplify the current stress analysis, the ripple i0 in the output current is ignored and its average value is recorded as I0. Similarly, for the inductor current ripple i of the first inductor L1 and the second inductor L2 L1 、i L2 are neglected, and their average currents are expressed as I L1 , I L2 and I L3 The average current of diode D is denoted as I D The capacitance charge balance equation of the first capacitor C1, the second capacitor C2, the third capacitor C3 and the filter capacitor Co is as follows:

[0069] The average current of the first inductor L1, L2 and L3 and the diode D is derived as

[0070] The stress across the current switch is written as

[0071] Because the traditional perturbation observation method uses a constant perturbation value, it is difficult to achieve an ideal balance between control accuracy and control speed. The present invention introduces the SOA algorithm, which, with its excellent numerical optimization capabilities, aims to dynamically determine the optimal perturbation step size of the perturbation observation method at different time points. In this application, the perturbation step size is set as the objective function of the SOA algorithm, and the fitness evaluation of the population is based on the change in the maximum power and voltage difference between adjacent moments. Specifically, the power P and voltage U output by the traditional perturbation observation method serve as the input data of the SOA algorithm to optimize the perturbation step size setting at the previous moment.

[0072] The key to combining the SOA algorithm with the perturbation-observation method for photovoltaic power generation systems is to use the SOA algorithm to accurately solve for the optimal perturbation step size. The SOA algorithm's search guidance is based on three core behaviors: egoistic behavior promotes individual self-improvement, altruistic behavior encourages knowledge sharing among populations, and proactive behavior allows the algorithm to proactively explore potential better solutions. Therefore, combining the optimization algorithm and the perturbation step size ΔU to be optimized, its expression is transformed from a fixed parameter as follows:

[0073] In the formula, the relevant parameters affecting the perturbation step length ΔU can refer to the basic principle of SOA, where the selfish behavior search direction is expressed as , the altruistic behavior search direction is expressed as And the pre-action behavior search direction is expressed as , sign is the sign function.

[0074] At the same time, since the perturbation step size is constant in the traditional hill climbing method, it is difficult to achieve both tracking accuracy and speed in the control algorithm. Especially in wind power generation systems, output power is the core indicator for measuring power generation quality. Power perturbation can effectively reduce the system response time and accelerate the maximum power point tracking (MPPT) process. Therefore, the present invention combines the artificial fish school algorithm with the power perturbation method and applies it to the MPPT control of wind power generation systems. In the MPPT control strategy of the present invention, the various parameters of the wind power generation system are first used as input parameters of the artificial fish school algorithm. The algorithm first performs a global search to determine the initial power perturbation step size. Subsequently, according to the power change ΔP of the wind power generation system, the power perturbation step size at subsequent moments is dynamically adjusted and calculated. In each iteration of the artificial fish school algorithm, the individual's moving step size (step) will be adaptively adjusted as its field of view (Visual) changes. This process involves a key parameter - the visual step joint coefficient ψ, whose mathematical expression is as follows:

[0075] Finally, the improved MPPT algorithms of the photovoltaic and wind power systems are combined to accurately track the MPPT, improve the efficiency of energy extraction from the photovoltaic system, and ensure excellent converter performance and maximum energy collection.

[0076] This paper designs a hybrid renewable energy system that integrates photovoltaic and wind power generation systems into the power grid, providing a continuous and reliable power supply for charging electric vehicles. The core innovation lies in the design and implementation of a high-gain bidirectional Zeta converter, which significantly improves the efficiency of the photovoltaic system by increasing the voltage level. To optimize power extraction, the system uses a maximum power point tracking control strategy based on a crowd search algorithm for photovoltaic power generation and an artificial fish school algorithm for wind power generation system power output control strategy, ensuring excellent converter performance and maximum energy collection.

[0077] Unless otherwise specified, the device components involved in the above embodiments are all conventional device components, and the structural settings, working modes or control modes involved are all conventional settings, working modes or control modes in the art unless otherwise specified.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limiting. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A hybrid renewable energy system, characterized in that: include: A bidirectional Zeta converter, an inverter, a photovoltaic power supply, and a wind power supply; the bidirectional Zeta converter includes a first switch tube, a second switch tube, a first capacitor, a second capacitor, a third capacitor, a filter capacitor, a first inductor, a second inductor, and a diode; the inverter includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube, and a sixth switch tube; the positive electrode of the photovoltaic power supply is connected to the drain of the first switch tube, and the source of the first switch tube is connected to the first end of the first capacitor and the first end of the first inductor. one end; the second end of the first capacitor is connected to the first end of the second inductor, the first end of the second capacitor and the drain of the second switch tube; the second end of the second inductor is connected to the anode of the diode and the first end of the third capacitor, and the cathode of the diode is connected to the second end of the second capacitor, the first end of the filter capacitor, the positive electrode of the wind power source, the drain of the first switch tube of the inverter, the drain of the third switch tube of the inverter and the drain of the fifth switch tube of the inverter; the source of the first switch tube of the inverter is connected to the drain of the second switch tube of the inverter; the drain of the third switch tube of the inverter is connected to the drain of the fourth switch tube of the inverter; The source of the fifth switch tube of the inverter is connected to the drain of the sixth switch tube of the inverter; and the inverter is connected to the power grid.

2. A hybrid renewable energy system according to claim 1, characterized in that: The inverter further includes a first filter inductor, a second filter inductor, a third filter inductor, a first energy storage capacitor, a second energy storage capacitor, and a third energy storage capacitor; the source of the first switch tube of the inverter is connected to the first end of the first filter inductor; the drain of the third switch tube of the inverter is connected to the first end of the second filter inductor; The source of the fifth switching tube of the inverter is connected to the first end of the third filter inductor; one end of the first energy storage capacitor is connected to the second end of the first filter inductor, and the other end is connected to the power grid; one end of the second energy storage capacitor is connected to the second end of the second filter inductor, and the other end is connected to the power grid; one end of the third energy storage capacitor is connected to the second end of the third filter inductor, and the other end is connected to the power grid.

3. A hybrid renewable energy system according to claim 1, characterized in that: The negative electrode of the wind power source, the second end of the filter capacitor, the second end of the third capacitor, the source of the second switch tube and the second end of the first inductor, the source of the second switch tube of the inverter, the source of the fourth switch tube of the inverter, and the source of the sixth switch tube of the inverter are all connected to the negative electrode of the photovoltaic power source.

4. A hybrid renewable energy system according to claim 1, characterized in that: The first switch tube and the second switch tube are both insulated gate bipolar transistors.

5. The hybrid renewable energy system according to claim 1, characterized in that: The diode is a ROHMS0KG silicon carbide Schottky diode.

6. A method for using a hybrid renewable energy system, based on the hybrid renewable energy system according to any one of claims 1 to 5, characterized in that: The following steps are involved: The DC power generated by the photovoltaic power source and the wind power generation system power source is input into the bidirectional Zeta converter; By alternately turning on the first switch tube and the second switch tube, the first inductor, the second inductor and the first capacitor, the second capacitor and the third capacitor are charged and discharged in stages to increase the input voltage; The boosted DC power is input into the three-phase inverter module, and the DC power is converted into AC power with the same frequency and phase as the power grid through PWM control of the first switch tube of the inverter, the second switch tube of the inverter, the third switch tube of the inverter, the fourth switch tube of the inverter, the fifth switch tube of the inverter, and the sixth switch tube of the inverter.

7. A method for controlling a photovoltaic power source of a hybrid renewable energy system, based on the hybrid renewable energy system according to any one of claims 1 to 5, characterized in that: The following steps are involved: In the initialization phase, the photovoltaic system parameters and environmental conditions are input, and a population search algorithm is used to generate a searcher population, where each individual represents a perturbation step length ΔU; The knowledge sharing of the objective function with the maximum power voltage difference at adjacent moments is carried out through fuzzy logic system; Assume that selfish behavior is the individual historical optimal direction, altruistic behavior is the global optimal direction, and proactive behavior is the historical change trend, and comprehensively update the search direction; The iterative process re-evaluates the population fitness according to the voltammetric equilibrium principle until convergence or the termination condition is reached; Output the optimal perturbation step size.

8. A method for controlling a wind power source in a hybrid renewable energy system, based on the hybrid renewable energy system according to any one of claims 1 to 5, characterized in that: The following steps are involved: Maximum power point tracking based on artificial fish school algorithm: Input wind power system parameters and initial algorithm configuration to generate an initial fish school, with each artificial fish corresponding to a candidate perturbation step size. By calculating the power difference ΔP at the current wind speed as the fitness value, the foraging, flocking, chasing or random walking behaviors are dynamically selected, and the perturbation step size is gradually updated; The foraging behavior adjusts the step direction according to the power change. The flocking and tail-chasing behaviors guide the fish to move to the adjacent optimal or global optimal position respectively. At the same time, the visual step joint coefficient ψ is introduced to balance the adaptive adjustment of the field of view and step length. The iterative optimization is performed until the power difference approaches zero or the maximum number of iterations is reached, and the optimal perturbation step size is finally output to achieve rapid tracking of the maximum power point.

9. A charging system for an electric vehicle, characterized in that: A hybrid renewable energy system comprising any one of claims 1 to 5.

10. A method for using an electric vehicle charging system, based on the electric vehicle charging system according to claim 9, characterized in that: The following steps are involved: When charging electric vehicles, electricity generated by photovoltaic and wind power is used to charge the electric vehicle batteries; if renewable energy is insufficient, it switches to grid power supply; When the electric vehicle battery has excess energy, the battery energy is fed back to the grid through the reverse operation of the bidirectional Zeta converter and inverter.

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