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Dynamic voltage-sharing control method for power module of chained multi-level converter

A technology of multi-level converters and power modules, which is applied in the direction of converting AC power input into AC power output, output power conversion devices, electrical components, etc., and can solve problems such as poor voltage equalization effect and inability to run stably for a long time , to avoid time delay, solve pressure equalization problems, and overcome technical difficulties

Active Publication Date: 2014-07-23
BEIJING SIFANG JIBAO AUTOMATION +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the poor voltage equalization effect under light load and dynamic load conditions when the existing voltage equalization control method is applied to a chained multilevel converter with a voltage level above 35kV, and cannot be used for a long time Problems with stable operation

Method used

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  • Dynamic voltage-sharing control method for power module of chained multi-level converter

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Embodiment 1

[0025] Embodiment 1 The technical solution of the present invention specifically comprises the following steps:

[0026] Step 1: Obtain the instantaneous values ​​of the capacitor voltages of n power modules of a certain phase through local sampling and optical fiber communication, respectively u dc1 ~ u dcn ;

[0027] Step 2: Through the sliding window, select the sampling value of the DC voltage in the last half of the power frequency cycle, and calculate the average value of the capacitor voltage of each module, that is, the DC voltage of the module;

[0028] Step 3: Calculate the average value of the DC voltage of all n power modules of this phase, and use it as the target value u of the DC voltage of a single power module of this phase dcref ;

[0029] Step 4: Set the target value u dcref Make a difference with the DC voltage of each module to get the DC voltage deviation Δu of the module dci , the DC voltage deviation and the coefficient K of the proportional contro...

Embodiment 2

[0040] Embodiment 2 A dynamic voltage equalization control method for a power module of a chained multilevel converter, specifically comprising the following steps:

[0041] Step 1: Obtain the instantaneous values ​​of the capacitor voltages of n power modules of a certain phase through local sampling and optical fiber communication, respectively u dc1 ~ u dcn ;

[0042] Step 2: Through the sliding window, select the sampling value of the DC voltage in the last half of the power frequency cycle, and calculate the average value of the capacitor voltage of each module, that is, the DC voltage of the module;

[0043] Step 3: Calculate the average value of the DC voltage of all n power modules of this phase, and use it as the target value u of the DC voltage of a single power module of this phase dcref ;

[0044] Step 4: Use the single-phase software phase-locked loop algorithm to detect the phase of the power frequency component in the output current of the chained multilevel ...

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Abstract

The invention discloses a dynamic voltage-sharing control method for a power module of a chained multi-level converter. The voltage-sharing method is performed by a single-phase software phase-locked loop, a sign function and a proportional controller connected in series, and comprises the steps that: the software phase-locked loop detects the phase of a power frequency component in the output current of the chained multi-level converter and inputs the phase information into the sign function to obtain the regulating direction of the voltage-sharing control, then the regulating variable of the voltage-sharing control is obtained by the proportional controller according to the direct voltage deviation of a single power module, at last the voltage-sharing component in the output voltage of the power module is obtained through multiplying the regulating direction with the regulating variable, and thus the output voltage of the module is obtained by summing the voltage-sharing component with the momentary value of the output voltage of the phase. The dynamic voltage-sharing control method overcomes harmonic current under the working condition of small current and influence of dynamic load which changes rapidly on the voltage sharing of the power module, and effectively solves the voltage-sharing problem of the chained multi-level converter under the working conditions of light load and dynamic load.

Description

technical field [0001] The invention belongs to the technical field of power electronic converters, and in particular relates to a dynamic voltage equalization control method for DC capacitors of power modules in chained multilevel converters. Background technique [0002] The dynamic voltage equalization of the power module has always been a key technical problem faced by the chained multi-level structure. In the application of the 10kV voltage level, the dynamic voltage equalization algorithm widely used at present takes the instantaneous value of the output current of the converter as the important Adjustment basis. In chain-type multilevel converters directly connected to 35kV and above power grids, the number of power modules connected in series is greatly increased, reaching dozens or even hundreds. The large increase in the number of modules in series makes the voltage equalization control of the power modules face more stringent application conditions. In the appli...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M5/00
Inventor 梅红明刘树刘建政王一史秋娟钟启迪石山操丰梅贾海林陈秋荣周前程
Owner BEIJING SIFANG JIBAO AUTOMATION
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