Control method of off-grid photovoltaic power generation system
A photovoltaic power generation system and control method technology, applied in photovoltaic power generation, power network operating system integration, AC network circuit and other directions, can solve the problem of off-grid system voltage/frequency stability control accuracy is poor, no system considers off-grid system voltage/frequency The mathematical relationship between the active and reactive power of the system and the frequent start and stop of the off-grid system can achieve the effect of rationally configuring the scale of energy storage.
Active Publication Date: 2022-02-22
SHANGHAI ELECTRIC POWER DESIGN INST
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Problems solved by technology
[0003] At present, the research on off-grid systems is mainly carried out around the concept of off-grid microgrid, and most of them study energy storage configuration and relay protection. The control is mainly realized by the balance between power output and load electricity consumption. There is no system to consider the mathematical relationship between the voltage / frequency of the off-grid system and the active / reactive power of the system, resulting in poor control accuracy of the voltage / frequency stability of the off-grid system. Off-grid system starts and stops frequently
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[0044] Such as figure 1 The off-grid photovoltaic system shown, where the voltage control system is as figure 2 As shown, the frequency control system such as Figure 4 shown.
[0045] Such as image 3 As shown, the steps of voltage control are as follows:
[0046] A1. The first step is to set the allowable operating voltage deviation ΔU of the system e , Rated operating voltage value U e and the rated operating frequency value f e , read the real-time operating parameters of the system, the operating parameters include the operating voltage value U at time t t , the operating frequency value f at time t t , Running active power value P at time t t , Inverter output active power value P at time t t G , Load active power value P at time t t L , Inverter active backup capacity ΔP at time t t G , Accumulated load cut-off value ΔP before time t t L , The inductive reactive value output by the reactive device at time t Output capacitive reactive power value of re...
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The invention discloses a control method for an off-grid photovoltaic power generation system, including voltage control and frequency control; the voltage control uses the difference between the real-time operating bus voltage of the system collected and the rated operating voltage of the system as an input variable, and uses voltage-active power mathematics The model calculates the output active power adjustment difference, issues active power adjustment commands through the system monitoring system, and adjusts the system active power balance to compensate for voltage deviations by increasing power output or shedding loads. Frequency control takes the difference between the collected real-time operating frequency of the system and the rated operating frequency of the system as an input variable, calculates the output reactive power adjustment difference through the frequency-reactive power mathematical model, and issues reactive power adjustment commands through the system monitoring system. The adjustment of the reactive power balance of the system compensates the frequency deviation. The invention ensures that the voltage / frequency in the off-grid photovoltaic or photovoltaic storage system is in the normal operating range, and maintains the operation stability of the off-grid system.
Description
technical field [0001] The invention relates to the technical field of photovoltaic power generation, in particular to a control method for an off-grid photovoltaic power generation system. Background technique [0002] With the development of the world economy, problems such as the shortage of traditional fossil energy, the aggravation of environmental pollution, and the increase in power demand have become increasingly prominent. Electric energy substitution has become the theme of today's energy utilization. On the one hand, my country's distributed photovoltaics are developing rapidly. With the increasing penetration rate of distributed photovoltaic systems connected to the power grid and the increasing demand for distributed photovoltaic off-grid island operation, distributed photovoltaic off-grid operation systems will become new energy power applications. On the other hand, regions without electricity such as Southeast Asia, Africa, and the Americas have an urgent dema...
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IPC IPC(8): H02J3/38H02J3/14H02J3/16
CPCH02J3/383H02J3/14H02J3/16H02J3/388H02J2203/20Y02E10/56Y04S20/222Y02E40/30Y02B70/3225
Inventor 林海涛于童周威崴崔云
Owner SHANGHAI ELECTRIC POWER DESIGN INST