CN-122026412-A - Common bus photovoltaic energy storage alternating current micro-grid simulation model construction method

Abstract

The invention discloses a common bus photovoltaic energy storage alternating current micro-grid simulation model construction method, which comprises the steps of constructing a micro-grid system architecture through cooperation of four core modules, defining simulation targets, carrying out digital modeling on each functional module of a micro-grid according to the micro-grid system architecture, constructing a simulation model, setting initial parameters of the simulation model and carrying out multi-experiment comparison on simulation scenes, optimizing the simulation model according to multi-experiment comparison results, repeating step S300 on the optimized simulation model, and obtaining a final micro-grid simulation model with qualified accuracy. And according to the micro-grid simulation model, accurate grid-connected synchronization is realized through the PLL. The model solves the problems of photovoltaic output fluctuation, unstable bus voltage, inverter harmonic pollution and the like, has high simulation precision and quick dynamic response, can accurately simulate the system operation characteristics under complex working conditions, provides reliable support for engineering design, parameter optimization and stability verification of the common bus photovoltaic energy storage micro-grid, and is suitable for scenes such as a distributed photovoltaic power station and the like.

Inventors

• CHEN HONGWEI
• PENG MINGWEI
• WU YINXUAN
• CHEN LING
• XIAO FAN
• ZHAO ZISHAN
• BAI JUN
• SHEN ZHOU
• TU KAILI
• GUO YUE

Assignees

• 中国能源建设集团浙江省电力设计院有限公司

Dates

Publication Date

20260512

Application Date

20260115

Claims (7)

1. 1. The method for constructing the simulation model of the common bus photovoltaic energy storage alternating current micro-grid is characterized by comprising the following steps of: S100, defining a micro-grid system architecture, and definitely simulating a target; S200, carrying out digital modeling on each functional module of the micro-grid according to the micro-grid system architecture, and constructing a simulation model; S300, setting initial parameters of a simulation model and performing multi-experiment comparison on a simulation scene; s400, optimizing the simulation model according to the multi-experiment comparison result, and repeating the step S300 on the optimized simulation model to obtain the final micro-grid simulation model with qualified accuracy.
2. 2. The method for constructing a simulation model of a common bus photovoltaic energy storage alternating current micro-grid according to claim 1, wherein the method for constructing the simulation model in the step S200 comprises a storage battery energy storage unit module digital model method, a grid-following inverter module digital model method and a photovoltaic module digital model construction method; The method for establishing the storage battery energy storage unit module digital model comprises the following steps: constructing a DC-DC conversion sub-module of a BUCK-BOOST topological structure, wherein the output end of the topological structure is connected with an energy storage converter, and the input end of the topological structure is connected with a storage battery, so that voltage and current double-loop control is achieved; with the assistance of BUCT-BOOST circuits, when the voltage of the energy storage direct current bus is smaller than a given threshold value, switching to a BOOST circuit by adjusting the working signal of the IGBT switching tube, and enabling power to flow from the storage battery module to the direct current bus; Wherein iL is an inductor current, vin is a battery voltage, i o is an output current, V dc is an inverter output voltage, R L is an inductor parasitic resistance, d is a duty ratio of the switching tube Q1, and the switching tube Q2 and the switching tube Q1 are complementarily turned on, so that the duty ratio of the switching tube Q2 is 1-d.
3. 3. The method for constructing the simulation model of the common bus photovoltaic energy storage alternating current micro-grid according to claim 2, wherein the method for constructing the digital model of the grid-following inverter module comprises the following steps: Constructing a half-bridge structure by connecting an IGBT in parallel with a diode, constructing a three-phase full-bridge topological structure by three groups of half-bridge structures, inputting 750/700V on a direct current side of the full-bridge topological structure, outputting 380V/50Hz on an alternating current side and sharing an alternating current bus, and rated power is 1000W; The photovoltaic side-to-grid converter adopts UI control, and the UI control is controlled through a dq rotating coordinate system; In an abc three-phase static coordinate system, the formulas of the active power Ps and the reactive power Qs at the system side are unique, and the expressions of the active power Ps and the reactive power Qs are obtained according to an instantaneous power equation: Wherein the method comprises the steps of , , , , , Is three-phase voltage and current; obtained by inverse park transformation: The formula in the park inverse transformation is brought into an inductance and capacitance differential equation, and meanwhile, the inverter is set to be in a normal working state, namely, only positive sequence is provided, no zero sequence is provided, and the power expression of dq rotation can be obtained as The power expression of dq rotation is calculated by converting three-phase voltage and current on the net side into d, q components of the dq rotation coordinate system, so that The d-axis component of the network side voltage is consistent with the direction of the vector of the network side voltage, and then a converted formula is obtained: The three-phase full-bridge topological structure is created through IGBT, the direct current side of the full-bridge topological structure is connected with 750/700V direct current bus, the output end of a bidirectional DC-DC converter which is connected with a Boost unit of a photovoltaic module and stores energy of a storage battery in a butt joint way, the alternating current side is connected with 380V/50Hz common alternating current bus, and the common alternating current bus is connected with a public power grid at the grid side, and the grid side is connected with an infinite power grid, so that the power frequency voltage of the power grid is constant, and the voltage of a parallel grid point is introduced due to the output voltage of a grid-connected inverter, so that Is unchanged only to The regulation is carried out to achieve the regulation of the active power output by the inverter, and the same is true only for Adjusting, namely adjusting reactive power output by the inverter; Inverter side output dq voltage component generation by feed-forward decoupling , The cross decoupling control equation is as follows: Wherein the method comprises the steps of , For the inversion side to output the dq voltage component, , As a function of the PI parameter of the power loop, , As a function of the current loop PI parameter, Is the dq voltage component on the grid side; Bringing equations (10), (11) into equation (9), the resulting decoupled dq-axis equation is related solely to the d-axis or q-axis: Decoupling is completed, and outer ring synchronous processing is combined: And finishing the setting of the parameters of the outer voltage ring and the inner current ring, and taking the parameters of the inner current ring as initial parameters of the optimization of the parameters of the outer voltage ring and the inner current ring.
4. 4. The method for constructing the simulation model of the common bus photovoltaic energy storage alternating current micro-grid according to claim 3, wherein the method for optimizing parameters of the outer ring and the inner ring of the voltage and the current comprises the following steps: collecting power grid voltage through a PLL, calculating voltage phase and frequency of the power grid, and simultaneously collecting a phase signal and an abc-dq converter to obtain a three-phase current signal, and converting the three-phase current signal into a dq coordinate system to obtain And A component; for dq double-axis parallel processing, d-axis voltage outer loop is used for collecting direct-current side voltage signals And calibrating DC voltage The difference is formed into differential negative feedback, and the differential negative feedback is output through a voltage ring PI controller Signal and with The signals are subjected to difference to obtain a differential signal of a current loop, and the differential signal is output after passing through a PI controller of the current loop and superimposing a coupling term A signal; q-axis setting And (3) with The signals are differenced to form a differential signal, and the differential signal is output through a PI controller of a current loop while superposing the coupling term The signals are subjected to dq-abc inverse transformation, PWM signals are sent to an inverter by a PWM (pulse-width modulation) output device to form closed loop control, a filtering module at the photovoltaic side adopts L filtering, a direct current bus capacitor C 1 =3 mF, direct current bus voltage Udc- =750V, a three-phase inductance at the grid-connected side, a resistance lg=3 mH, rg=3/8 ohm and a grid-connected side line voltage amplitude egd =311V; Further setting parameters The model of the controlled object of the control equation of the current inner loop is: the open loop function of the current loop is thus: The closed loop transfer function is thus: Designing the zero point of the PI controller of the voltage ring at wbw, v/3, and setting the open loop gain of kgp, v at the point to be 1; and further acquiring an equivalent modulation wave equation of the SVPWM on the ABC coordinate system to display the hidden modulation wave of the SVPWM.
5. 5. The method for constructing the simulation model of the common-bus photovoltaic energy-storage alternating-current micro-grid according to claim 4, wherein the method for displaying the hidden modulation wave of the SVPWM comprises the following steps: The voltage and current double-loop control is adopted, and the following formula is obtained by combining the space voltage vector approximation principle: where m is the SVPWM modulation factor, Further, the average value of the voltages of each phase in the first sector is obtained: Similarly, the modulation wave function of other sectors is obtained, and the phase voltage modulation function of each phase is as follows: a modulated wave of an implied modulated wave of SVPWM is obtained.
6. 6. The method for constructing the simulation model of the common-bus photovoltaic energy storage alternating-current micro-grid according to claim 2, wherein the multi-experiment comparison method comprises the following steps: setting an experimental control group: The control group 1 is a traditional single-stage photovoltaic system, wherein the control group 1 does not comprise a storage battery energy storage unit, a photovoltaic array is directly connected with a grid through an inverter after DC-DC boosting, and MPPT control is performed by adopting a conventional disturbance observation method; the control group 2 is a conventional SPWM control system, wherein the control group 2 comprises an energy storage unit, but adopts a traditional sinusoidal pulse width modulation SPWM in an inverter modulation link, and does not adopt a dq axis feedforward decoupling control strategy; under the steady-state operation condition, the output current waveforms and the spectrum analysis results of the control group 1 and the control group 2 are obtained to carry out the validity verification of the inverter control strategy.
7. 7. The method for constructing a simulation model of a common-bus photovoltaic energy-storage ac micro-grid according to claim 6, wherein the method for obtaining the simulation model of the final micro-grid in step S400 comprises: The control strategy of the network inverter is optimized by adopting a feedforward cross decoupling method, PI parameters are set again based on a mode maximum value method, and the specific setting calculation process is as follows: Setting the bandwidth as 500Hz, and setting the parameters of the current inner loop as follows: simultaneously decoupling the d, q axis components; Setting a voltage outer ring on the basis of a current inner ring, setting the bandwidth of the voltage outer ring to be one tenth of that of the current ring, namely 50Hz, and setting the parameters of the voltage outer ring to be: and substituting the optimized control parameters into the simulation model, and repeating the step S300 to obtain final parameters to obtain a final micro-grid simulation model.

Description

Common bus photovoltaic energy storage alternating current micro-grid simulation model construction method Technical Field The invention relates to the technical field of micro-grid simulation, in particular to a common bus photovoltaic energy storage alternating current micro-grid simulation model construction method. Background Under the background that the 'double carbon' target promotes the global energy structure to be converted into clean and low-carbonization, the photovoltaic power generation has become one of the fastest-growing renewable energy forms worldwide due to the characteristics of renewable resources, zero emission in operation and the like. According to International Energy Agency (IEA) data, the new installed quantity of the global photovoltaic in 2023 breaks through 400GW, the accumulated installed quantity exceeds 2TW, and the photovoltaic in 2030 is expected to account for more than 20% of the global power supply. However, the output characteristic of the photovoltaic power generation is highly dependent on natural conditions, namely the severe fluctuation of the illumination intensity from 200W/m2 to 1000W/m2 and the change of the ambient temperature from 10 ℃ to 30 ℃ can lead the fluctuation range of the output power of the photovoltaic array to reach over +/-50 percent, directly cause voltage deviation and frequency fluctuation at the grid-connected side, even trigger relay protection misoperation of a power grid, severely restrict the large-scale consumption of the photovoltaic energy, and bring serious challenges to the safe and stable operation of the power distribution network. In order to solve the problem of fluctuation of the photovoltaic output, the common bus photovoltaic energy storage alternating-current micro-grid provided by the invention has the advantages of centralized bus management and flexible adjustment of energy storage, and becomes a core technical route for balancing the photovoltaic output and improving the stability of a system. According to the structure, the photovoltaic unit, the energy storage unit, the inverter and other equipment are connected into the same direct current bus, so that the system topology structure is simplified (the wiring complexity is reduced by more than 30%), the equipment redundancy cost is reduced (compared with the distributed structure, the cost is reduced by 15% -20%), and the structure is widely applied to scenes such as distributed photovoltaic power stations and micro-grid energy storage systems. However, in actual operation and simulation modeling, the architecture still faces three main core technical bottlenecks, the DC-DC conversion efficiency is low, the bus voltage stability is poor, the energy storage unit has weak bidirectional regulation capability and low dynamic response speed, and the energy storage unit is seriously polluted by harmonic waves and has low synchronization precision with a grid-connected inverter, and the prior art scheme is difficult to effectively break through. Disclosure of Invention The invention provides a method, equipment and a storage medium for constructing a simulation model of a common bus photovoltaic energy storage alternating current micro-grid, which can at least solve one of the technical problems in the background technology. In order to achieve the above purpose, the present invention adopts the following technical scheme: the method for constructing the simulation model of the common bus photovoltaic energy storage alternating current micro-grid is characterized by comprising the following steps of: S100, defining a micro-grid system architecture, and definitely simulating a target; S200, carrying out digital modeling on each functional module of the micro-grid according to the micro-grid system architecture, and constructing a simulation model; S300, setting initial parameters of a simulation model and performing multi-experiment comparison on a simulation scene; s400, optimizing the simulation model according to the multi-experiment comparison result, and repeating the step S300 on the optimized simulation model to obtain the final micro-grid simulation model with qualified accuracy. Further, the simulation model constructing method in the step S200 comprises a storage battery energy storage unit module digital model constructing method, a grid-following inverter module digital model constructing method and a photovoltaic module digital model constructing method; The method for establishing the storage battery energy storage unit module digital model comprises the following steps: constructing a DC-DC conversion sub-module of a BUCK-BOOST topological structure, wherein the output end of the topological structure is connected with an energy storage converter, and the input end of the topological structure is connected with a storage battery, so that voltage and current double-loop control is achieved; with the assistance of BUCT-BOOST circuits, when the voltage of the energy