CN-121983936-A - Floating type photovoltaic-energy storage-oriented power converter structure and coordination control method

Abstract

The invention belongs to the field of power electronics, and particularly relates to a floating photovoltaic-energy storage-oriented power converter structure and a coordination control method. The converter consists of a photovoltaic DC-DC Boost conversion circuit and an energy storage bidirectional Buck-Boost circuit, wherein the photovoltaic panel is used as an input, the energy storage battery is used as an energy unit, and the output of the photovoltaic DC-DC Boost conversion circuit and the energy storage bidirectional Buck-Boost circuit are connected with the same direct current bus to supply power to direct current ship body and port direct current loads. The circuit adopts a power MOSFET as a switching device, the energy storage circuit is provided with an overcurrent and overvoltage protection module, and the inductor adopts a silicon steel sheet iron core with low hysteresis loss so as to reduce energy consumption. The coordination control method comprises the steps of obtaining photovoltaic parameters adapting to a dynamic water environment through environmental data and a correction coefficient, establishing an engineering mathematical model to deduce output characteristics, screening photovoltaic maximum power through a niche algorithm, determining an energy storage working state according to load requirements, and generating charge and discharge instructions through calculating end voltage and charge state of a storage battery to realize cooperative operation.

Inventors

• SU XIAOQING
• HUANG JIAJI
• WEI ANQIANG
• CHEN SHAOWEN
• WANG BIN
• ZHOU LIJUN
• HUANG BO
• JIANG MIN
• WU JIA
• ZHOU KAI
• LI GUANGDI
• YI WENTAO
• CHEN YUNRONG
• Zhao Datian
• XUE WEI
• LI SHUANG
• KONG LIANG
• ZHANG HANXIONG
• LI XIAOBIN
• LUO FENG

Assignees

• 国网江西省电力有限公司九江供电分公司

Dates

Publication Date

20260505

Application Date

20251223

Claims (10)

1. 1. The power converter structure for floating photovoltaic-energy storage consists of a photovoltaic DC-DC Boost conversion circuit and an energy storage bidirectional Buck-Boost circuit, and is characterized in that the photovoltaic DC-DC Boost conversion circuit takes a photovoltaic panel as a direct current power supply input, and the energy storage bidirectional Buck-Boost circuit takes an energy storage battery as an energy storage and release unit; the output ends of the photovoltaic DC-DC Boost conversion circuit and the energy storage bidirectional Buck-Boost circuit are connected into the same direct current bus together, and are connected into a load in parallel through the direct current bus, wherein the load is a direct current ship load and a port direct current load; The photovoltaic DC-DC boost conversion circuit is provided with a Cin1 input voltage stabilizing capacitor, an L1 inductor and two power switching devices S1-S2, one end of the inductor L1 is connected in series between the S1 and the S2, the other end of the inductor L1 is connected with the output end of the photovoltaic panel, and the output voltage stabilizing capacitor Co1 is connected between the output side of the S1-S2 and the direct current bus in parallel; The energy storage bidirectional Buck-Boost conversion circuit is provided with a Cin2 input voltage stabilizing capacitor, an L2 inductor and two power switching devices S3-S4, one end of the inductor L2 is connected in series between the S3 and the S4, the other end of the inductor L2 is connected with the output end of the energy storage battery, and the output voltage stabilizing capacitor Co2 is connected between the output side of the S3-S4 and the direct current bus in parallel.
2. 2. A floating photovoltaic-energy storage oriented power converter structure according to claim 1, wherein the power switching tubes S1-S4 are power metal-oxide semiconductor field effect transistors.
3. 3. The floating photovoltaic-energy storage oriented power converter structure according to claim 1, wherein the energy storage bidirectional Buck-Boost circuit is provided with an overcurrent protection module and an overvoltage protection module, the overcurrent protection module realizes threshold triggering by sampling the current of an inductor L2, the overvoltage protection module starts clamping action by monitoring the voltage of a direct current bus, the inductor L2 is made of a silicon steel sheet iron core material with low hysteresis loss, and the energy loss of the circuit is reduced.
4. 4. The coordination control method of the floating photovoltaic-energy storage oriented power converter structure is characterized by comprising the following steps of: S1, acquiring real-time environment data, and correcting the standard environment photovoltaic parameters by combining a voltage temperature correction coefficient, a current temperature correction coefficient and an irradiance correction coefficient to obtain photovoltaic parameters adapting to the current dynamic water environment; s2, building a photovoltaic cell engineering mathematical model based on the photovoltaic parameters of the S1 adapted to the current dynamic water environment, and deducing a real-time photovoltaic cell I-U curve and a power curve to obtain photovoltaic output characteristics; s3, based on the photovoltaic output characteristics of the S2, screening out the maximum peak value of the photovoltaic average power through a niche algorithm displacement mechanism, penalty coefficient calculation and sliding filtering, and determining the maximum photovoltaic power; S4, comparing the photovoltaic maximum power of the S3 with the real-time power requirement of the direct current ship body load and the port direct current load, and determining the working state of the energy storage unit; And S5, respectively calculating the terminal voltage of the storage battery, the corresponding controlled source voltage and the state of charge of the storage battery according to the working state of the energy storage unit determined in the step S4, analyzing and generating a charge-discharge current instruction, and executing the instruction to realize coordination control.
5. 5. A coordinated control method for a floating photovoltaic-energy storage power converter structure according to claim 3, wherein in said step S1, standard environmental photovoltaic parameters are modified, and the correlation expression is as follows: ; In the formula, Representing the difference between the actual operating temperature of the photovoltaic cell and the standard ambient temperature, Indicating the actual operating temperature of the photovoltaic cell, Representing the temperature in a standard environment, at 298, Indicating the corrected open circuit voltage of the photovoltaic cell, Represents the open circuit voltage of the photovoltaic cell under standard conditions, The temperature correction coefficient representing the current is shown, Representing a natural logarithmic function, Represents a natural constant of the natural product, Representing the irradiance correction factor of the voltage, Representing the actual irradiance of the photovoltaic cell, Represents the irradiance in a standard environment, Indicating the short-circuit current after correction of the photovoltaic cell, Representing the short-circuit current of the photovoltaic cell in a standard environment, The temperature correction coefficient representing the voltage is calculated, Representing the maximum power point voltage after correction of the photovoltaic cell, Representing the maximum power point voltage of the photovoltaic cell under standard circumstances, Indicating the maximum power point current after photovoltaic cell modification, Representing the maximum power point current of the photovoltaic cell under standard circumstances, Represents the open circuit voltage of the photovoltaic cell under standard conditions, Representing the short-circuit current of the photovoltaic cell in a standard environment, Representing the maximum power point voltage of the photovoltaic cell under standard circumstances, Representing the maximum power point current of the photovoltaic cell under standard circumstances.
6. 6. A coordinated control method of a floating photovoltaic-energy storage oriented power converter structure according to claim 3, characterized in that in step S2, a mathematical model of photovoltaic cell engineering is established, and the correlation expression is as follows: ; In the formula, Representing the output current of the photovoltaic cell, Representing the output voltage of the photovoltaic cell, Representing the short-circuit current of the photovoltaic cell, Indicating the set weighting factor(s) are set, Indicating the set weighting factor(s) are set, Representing parameters in a mathematical model of the photovoltaic cell engineering, Representing the current at the maximum power point of the photovoltaic cell, Representing the voltage at the maximum power point of the photovoltaic cell, Representing the open circuit voltage of the photovoltaic cell, Representing a natural logarithmic function, The representation supplementary notes represent the short-circuit current of the photovoltaic cell, The representation supplementary notes represent the open circuit voltage of the photovoltaic cell, Representing the current at the maximum power point of the photovoltaic cell, Representing the voltage at the maximum power point of the photovoltaic cell.
7. 7. The coordination control method for a floating photovoltaic-energy storage oriented power converter structure according to claim 6, wherein the construction of the mathematical model of the photovoltaic cell is improved by the mathematical model of the photovoltaic cell, and the correlation expression is as follows: ; In the formula, Representing the output current of the photovoltaic cell, Representing the output voltage of the photovoltaic cell, Representing the current produced by the photovoltaic cell due to illumination, Representing the reverse saturation current of the diode, Representing the charge constant, the value is 1.602 multiplied by 10 -19 , Representing the ideality factor of the diode, Representing the total number of series of photovoltaic cells, The Boltzmann constant is expressed, the value is 1.38X10 -23 , Indicating the temperature of the photovoltaic cell, Representing the series resistance in the equivalent circuit of the photovoltaic cell, Representing the parallel resistance in the equivalent circuit of the photovoltaic cell, Indicating the current through the diode.
8. 8. The coordinated control method of a floating photovoltaic-energy storage oriented power converter structure according to claim 3, wherein in step S3, a maximum peak value of photovoltaic average power is screened out, and a photovoltaic MPPT algorithm is used, and the correlation expression is as follows: ; wherein P (Ui) is the actual fitness, pp (Ui) is the punishment fitness, P (Ui) is the punishment coefficient applied to the individual i, the number of the niches which are already divided is always smaller than 1:n, ui is the position of the individual i, uc (n) is the position of the niche center which is already divided, lambda is the distance coefficient, and the punishment range is smaller when lambda is larger.
9. 9. A method of coordinated control of a floating photovoltaic-energy storage oriented power converter structure according to claim 3, characterized in that in step S5, the terminal voltage of the battery and the corresponding controlled source voltage are calculated, the correlation being expressed as follows: ; In the formula, Represents the terminal voltage of the storage battery, Representing the controlled source voltage of the battery, Indicating the charge-discharge current of the battery, Represents the internal resistance of the storage battery, Representing the internal potential of the battery, The parameters of the voltage-dependent transformation are indicated, Indicating the maximum capacity of the battery, Indicating the integral of battery charge-discharge current with respect to time The parameters of the discharge curve of the storage battery are represented, Represents a natural constant of the natural product, The parameters of the discharge curve of the storage battery are represented, Representing the controlled source voltage of the battery, Representing a controlled voltage source in the battery equivalent circuit.
10. 10. A coordinated control method of a floating photovoltaic-energy storage oriented power converter structure according to claim 3, characterized in that in step S5, the state of charge of the storage battery is calculated, and the correlation expression is as follows: ; In the formula, Indicating the state of charge of the battery, Indicating the initial state of charge of the battery, Indicating the integral of the battery charge-discharge current with respect to time, Indicating the maximum capacity of the battery, Indicating a value range of 0-1.

Description

Floating type photovoltaic-energy storage-oriented power converter structure and coordination control method Technical Field The invention belongs to the field of power electronics, and particularly relates to a floating photovoltaic-energy storage-oriented power converter structure and a coordination control method. Background With the acceleration of global energy conversion, floating photovoltaics have been attracting attention as an important direction of renewable energy development. Under the background, a floating type photovoltaic system is generated, the photovoltaic module is suspended on the water surface through the floating body platform, the limitation of water depth is broken through, and the obvious development potential is shown. According to statistics, floating photovoltaic resources can be developed in the global offshore area, which is more than 4000GW and is equivalent to more than 5 times of the total amount of the current global photovoltaic installation. The novel energy utilization form not only can effectively relieve land resource shortage, but also can provide clean energy guarantee for special scenes such as open sea islands, ocean platforms, inland ports and the like. Compared with land and pile foundation type photovoltaic systems, floating type photovoltaic faces significant differences in structural design, energy conversion, system control and the like. Firstly, six-degree-of-freedom motion of the floating body platform under the action of water body power can continuously change the spatial attitude of the photovoltaic module. Studies have shown that when the float pitch angle exceeds 5 deg., the change in the incident angle of the photovoltaic panel will result in an irradiance loss exceeding 8%, and that such fluctuations have high frequency characteristics of 0.1-2Hz, causing the generated power to exhibit a sustained pulsation characteristic. Secondly, the PID effect of the component is accelerated by the high humidity and high salt spray characteristics of the water environment, so that the annual attenuation rate of the power generation efficiency is improved by 0.5-0.8 percent compared with that of a land system. These characteristics make it difficult for the conventional MPPT control algorithm to meet the requirements on tracking accuracy and response speed, and the conventional PID control can generate a power tracking error of more than 15% under wave disturbance. The current research focuses on a single technical link, and lacks deep analysis on a full-chain coupling mechanism of wave disturbance, power generation fluctuation, energy storage response and system stability. The existing control strategy is often based on a static environment assumption, and dynamic association of floating body motion and electrical parameters is not fully considered, so that the problems of control lag, energy loss and the like exist in practical application. Disclosure of Invention In order to thoroughly solve the problems of the photovoltaic power pulsation caused by the floating body movement, component efficiency attenuation caused by the water environment, insufficient tracking precision, lagged response speed and lack of coupling mechanism analysis of the traditional control algorithm, the invention provides a floating photovoltaic-energy storage oriented power converter structure and a coordination control method, which are used for adapting the water dynamic environment by optimizing the converter topology structure and combining dynamic parameter correction and full chain coordination control strategy, precisely matching the photovoltaic output characteristic with load demand and energy storage response, effectively reducing power loss and control error, improving the system operation stability and energy utilization efficiency, and comprises the following specific technical scheme: The power converter structure for floating photovoltaic-energy storage consists of a photovoltaic DC-DC Boost conversion circuit and an energy storage bidirectional Buck-Boost circuit, wherein the photovoltaic DC-DC Boost conversion circuit takes a photovoltaic panel as a direct current power supply input, and the energy storage bidirectional Buck-Boost circuit takes an energy storage battery as an energy storage and release unit; the output ends of the photovoltaic DC-DC Boost conversion circuit and the energy storage bidirectional Buck-Boost circuit are connected into the same direct current bus together, and are connected into a load in parallel through the direct current bus, wherein the load is a direct current ship load and a port direct current load; The photovoltaic DC-DC boost conversion circuit is provided with a Cin1 input voltage stabilizing capacitor, an L1 inductor and two power switching devices S1-S2, one end of the inductor L1 is connected in series between the S1 and the S2, the other end of the inductor L1 is connected with the output end of the photovoltaic panel, and the