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Current control method and system for medium-voltage direct-hanging energy storage converter in non-ideal power grid

An energy storage converter, current control technology, applied in photovoltaic power generation, electrical components, energy storage and other directions, can solve the problems of high harmonic content of grid-connected current, unbalanced grid voltage, etc., to improve and suppress grid-connected current. Low-order current harmonics, the effect of easy engineering application

Active Publication Date: 2021-11-09
NANJING NARI GROUP CORP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is how to eliminate the high harmonic content of cascaded multi-level energy storage inverter grid-connected current caused by unbalanced grid voltage and harmonic pollution in grid voltage under non-ideal grid conditions The problem

Method used

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  • Current control method and system for medium-voltage direct-hanging energy storage converter in non-ideal power grid
  • Current control method and system for medium-voltage direct-hanging energy storage converter in non-ideal power grid
  • Current control method and system for medium-voltage direct-hanging energy storage converter in non-ideal power grid

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Embodiment 1

[0061] 1. System structure and workflow

[0062] Such as figure 1 As shown, the current control system of the medium-voltage direct-connected energy storage converter under the non-ideal grid includes: cascaded multi-level energy storage inverter system (1), abc / αβ converter (2), the first SOGI- OSG biquad generalized integrator (3), PLL phase-locked loop (4), αβ / dq converter (5), current command calculation module (6), abc / dq converter (7), second SOGI-OSG biquad generalized integrator (8), ωL multiplier (9), PI-HR controller (10), first dq / abc converter (11), second dq / abc converter (12), PS- PWM phase-shifting carrier modulator (13).

[0063] Collect the grid-side three-phase voltage u of the cascaded multi-level energy storage inverter system (1) a , ub , u c Input to the abc / αβ converter (2) for Clark transformation to obtain the static coordinate system voltage u α , u β , to collect the grid-side three-phase current i of the cascaded multi-level energy storage inv...

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Abstract

The invention discloses a current control method and system for a medium-voltage direct-hanging energy storage converter in a non-ideal power grid, belongs to the technical field of electric energy storage conversion, and solves the problem of high harmonic content of grid-connected current of a cascaded multi-level energy storage inverter caused by unbalanced power grid voltage and harmonic pollution in the power grid voltage under the working condition of the non-ideal power grid; a SOGI-OSG double-second-order generalized integrator is adopted to separate a positive sequence and a negative sequence in the grid-side current, the positive sequence component and the negative sequence component in the grid-side current are respectively controlled, and the output of a PI-HR controller and the output of an omega L multiplier are adopted to carry out feedforward decoupling operation, so independent control of d-axis and q-axis components is realized; a PI-HR controller is used for suppressing fluctuation of grid-side current and low-order harmonic components, so zero-static-error tracking can be performed on d-axis and q-axis direct-current active components, and low-order current harmonics can be effectively inhibited; the method is suitable for grid-connected current improvement of a multi-target constraint medium-voltage direct-hanging energy storage converter under a non-ideal power grid, can enable three-phase network access current to be sine and balanced, and facilitates the engineering application.

Description

technical field [0001] The invention belongs to the technical field of electric energy storage and conversion, and in particular relates to a current control method and system for a medium-voltage direct-connected energy storage converter under a non-ideal power grid. Background technique [0002] In recent years, in order to solve the global energy crisis and the increasingly serious problems of environmental pollution, more and more renewable energy sources have been integrated into the grid. At the same time, the requirements for interface converters are getting higher and higher. Among them, the cascaded H-bridge inverter has the advantages of multi-level, which makes the output voltage of the AC side closer to the sine wave and reduces the volume of the filter inductor, so it is widely used in photovoltaic grid-connected inverters and has been recognized domestically. Extensive research by foreign scholars. [0003] However, as more and more new energy sources are con...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/32H02J3/01H02J3/26
CPCH02J3/381H02J3/32H02J3/01H02J3/26H02J2203/20H02J2300/24Y02E10/56Y02E40/50Y02E40/40Y02E70/30
Inventor 魏星
Owner NANJING NARI GROUP CORP
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