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Model predictive control method and system for three-level inverter

A technology of three-level inverter and model predictive control, applied in photovoltaic power generation, electrical components, circuit devices, etc., can solve problems such as large current distortion on the AC side, and achieve the effect of simplifying complexity

Active Publication Date: 2019-10-08
SHANDONG LABOR VOCATIONAL & TECHN COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, when T-type three-level inverters are used in photovoltaic power generation systems, the traditional model predictive control assumes that the voltage of the upper capacitor is equal to the voltage of the lower capacitor, so there is a problem of large current distortion on the AC side.

Method used

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  • Model predictive control method and system for three-level inverter

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Embodiment 1

[0037] In one or more embodiments, a model predictive control method for a three-level inverter is disclosed. The research object of this embodiment is a T-type three-level inverter in a photovoltaic power generation system. In order to make the photovoltaic generator provide as much power as possible, without special instructions, the T-type three-level inverter in this embodiment operates at unity power factor.

[0038] A photovoltaic power generation system based on a three-level inverter as an AC / DC interface converter such as figure 1 As shown, including: photovoltaic panels, three-level grid-connected inverter and public grid.

[0039] The main circuit topology of the T-type three-level inverter includes: filter L 1 ; The equivalent resistance in the filter is R 1 ; 12 switching tubes S a1 , S a2 , S a3 , S a4 , S b1 , S b2 , S b3 , S b4 , S c1 , S c2 , S c3 , S c4 and DC side filter capacitor C p , C n . Regarding the driving strategy of the switch tube...

Embodiment 2

[0072] In one or more implementations, a model predictive control system for a three-level inverter is disclosed, including:

[0073] A module for setting active current reference value and reactive current reference value;

[0074] A module for converting the reference current in the dq coordinate system into the reference value of the current in the αβ coordinate system through dq / αβ coordinate transformation;

[0075] A module for obtaining the mathematical model of the three-level inverter in the αβ static coordinate system according to the topology structure of the three-level inverter;

[0076] A module for obtaining the reference value of the inverter bridge arm output voltage according to the reference value of the current in the αβ coordinate system based on the mathematical model;

[0077] It is used to select the space voltage vector closest to the inverter bridge arm output voltage reference value from the finite set of space voltage vectors through the cost funct...

Embodiment 3

[0079] In one or more embodiments, a terminal device is disclosed, including a server, the server includes a memory, a processor, and a computer program stored on the memory and operable on the processor, and the processor executes the The program realizes the model predictive control method of the three-level inverter in the first embodiment. For the sake of brevity, details are not repeated here.

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Abstract

The invention discloses a model predictive control method and system for a three-level inverter. The method comprises the steps of: setting the output active current set value of a photovoltaic grid-connected inverter, and setting a reactive current set value as zero; by means of dq / [alpha][beta] coordinate transformation, converting the reference current of the photovoltaic grid-connected inverter in an output dq coordinate system into a reference value of the current in an [alpha][beta] coordinate system; according to the topological structure of the three-level inverter, obtaining a mathematical model of the three-level inverter in an [alpha][beta] static coordinate system; based on the mathematical model, obtaining the reference value of the output voltage of an inverter bridge arm according to the reference value of the current in the [alpha][beta] coordinate system; selecting the space voltage vector closest to the reference value of the inverter bridge arm output voltage from afinite set space new voltage vectors by a value function, in order to control the state of each switching transistor in the next switching period and thereby control the AC-side current of the three-level inverter. The method can solve the low efficiency and the high AC-side harmonic current THD of a photovoltaic power generation system.

Description

technical field [0001] The invention belongs to the technical field of dual MPPT photovoltaic power generation, and in particular relates to a model predictive control method and system for a three-level inverter. Background technique [0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art. [0003] In recent years, with the increasing energy crisis, renewable energy has developed rapidly. Photovoltaic power generation has great potential for development due to its abundant reserves and wide distribution among renewable energy sources. According to the report statistics, in 2018, the new installed capacity of photovoltaic power generation in the country was 44.26 million kilowatts, and the cumulative grid-connected capacity reached 174 million kilowatts, accounting for about 9% of the total installed capacity of power supply. As the interface between the photovoltaic generato...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/483H02M7/5387H02J3/01H02J3/38
CPCH02J3/01H02J3/385H02M7/483H02M7/53875Y02E10/56Y02E40/40
Inventor 陈华王灿运孙斌边慧慧刘茜
Owner SHANDONG LABOR VOCATIONAL & TECHN COLLEGE