CN110768555B - Power module capacitor voltage balance strategy considering input frequency - Google Patents

Power module capacitor voltage balance strategy considering input frequency Download PDF

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Publication number
CN110768555B
CN110768555B CN201911000413.9A CN201911000413A CN110768555B CN 110768555 B CN110768555 B CN 110768555B CN 201911000413 A CN201911000413 A CN 201911000413A CN 110768555 B CN110768555 B CN 110768555B
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power module
voltage
power
diff
power modules
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CN201911000413.9A
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CN110768555A (en
Inventor
周登波
王瑛龙
姚言超
徐攀腾
宋述波
郑星星
严海健
杨学广
李倩
焦石
李建勋
朱博
郭云汉
柳林海
顾硕铭
谷裕
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Guangzhou Bureau of Extra High Voltage Power Transmission Co
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Guangzhou Bureau of Extra High Voltage Power Transmission Co
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade

Abstract

The invention discloses a power module capacitance-voltage balance strategy considering input frequency, wherein after a valve control system receives bridge arm voltage modulation waves, the number of power modules required to be input in the period is calculated according to the magnitude of the capacitance voltage of the power modules, and is compared with 0 and the total number N of the bridge arm power modulesSMThe number N of power modules put into the previous periodon_oldAnd comparing, referring to whether the bridge arm current is charged or discharged, and finally determining the input power module by combining the input frequency. When the capacitor voltage balance control of the power module is realized, two important parameter indexes of the input frequency of the power module and the capacitor voltage are comprehensively considered, the direct-current voltage requirement is met, the power module has equal service life, and the equipment maintenance period is shortened.

Description

Power module capacitor voltage balance strategy considering input frequency
Technical Field
The invention relates to a flexible direct current transmission technology, in particular to a power module capacitor voltage balance strategy considering input frequency.
Background
Compared with the conventional direct-current transmission technology, the flexible direct-current transmission related technology has the advantages of no need of reactive compensation, no problem of commutation failure, convenience in active power and power adjustment, low harmonic level, suitability for forming a multi-terminal direct-current system and the like, and the flexible direct-current transmission related technology is rapidly developed, wherein the flexible direct-current transmission system based on an MMC (modular multilevel converter) topological structure has the most representative and technical advantages.
As shown in fig. 1, the MMC is composed of six bridge arms, each of which is composed of N cascaded power modules (also called submodules) and a series reactor, and typical power modules are divided into full-bridge power modules and half-bridge power modules according to different structures. The full-bridge power module comprises 4 switch modules T1-T4 and a capacitor, the half-bridge power module comprises 2 switch modules T1-T2 and a capacitor, and each switch module is formed by connecting an Insulated Gate Bipolar Transistor (IGBT) and a diode in an anti-parallel mode.
Fig. 2 is a logic diagram of a conventional power module capacitance-voltage balancing strategy, where the meanings of variables in the diagram are as follows: n is a radical ofon-the number of power modules to be put into the cycle; n is a radical ofSMIn a single legThe total number of power modules; n is a radical ofon_old-the number of power modules put in the previous cycle; n is a radical ofdiff-the difference between the number of power modules put into this cycle and the previous cycle; i.e. iarm-bridge arm current, greater than zero, charging the power module, otherwise discharging △ Umax△ U power module voltage differencemax_ref-a power module voltage difference reference value.
The specific balancing strategy is as follows:
after the valve control system receives the modulation waves sent by the group control system, the number N of the power modules needing to be put into the system is calculated according to a nearest level approximation methodonIf the power is 0, all power modules are cut off; if equal to NSMAll power modules are put into operation; otherwise, the number N of the inputs is equal to the number N of the inputs in the previous periodon_oldSubtracting to obtain a difference value Ndiff。
NdiffWhen the current is greater than 0, if the bridge arm current iarmIf > 0, then N is selected in the power module that has been cut offdiffPutting the power module with the minimum capacitor voltage into the power module, otherwise, putting N into the power modulediffAnd the power module with the highest capacitor voltage.
NdiffWhen the voltage is equal to 0, if the power module voltage difference value is △ UmaxGreater than reference value △ Umax_refAnd selecting the module with the highest and the lowest capacitance voltage from the switched-on and switched-off sub-modules for switching, otherwise, keeping the modules unchanged.
NdiffWhen less than 0, if bridge arm current iarmIf > 0, then in the charged Non_oldCut | N in Individual modulesdiffThe power module with the highest voltage of | N capacitors is cut off otherwisediffAnd | power modules with lowest capacitor voltage.
It can be seen that in the existing flexible direct current transmission system based on the modular multilevel voltage source converter, when the bridge arm current charges the power module, the power module with the minimum capacitance voltage is put into the power module with the minimum capacitance voltage or the power module with the highest capacitance voltage is cut off by the power module capacitance voltage balance strategy; when the bridge arm current discharges the power module, the capacitor voltage balance strategy is used for switching the power module with the highest capacitor voltage or switching off the power module with the smallest capacitor voltage, the method only takes the size of the capacitor voltage as the only judgment standard, but neglects the important characteristic that electronic devices have certain switch service life, if the same power module is switched frequently, the service life of the power module is reduced, and the equipment maintenance period is shortened.
Disclosure of Invention
Aiming at the important defect that the existing power module capacitor voltage balance strategy only considers the size of capacitor voltage and neglects the certain switch service life of electronic devices, the invention provides the power module capacitor voltage balance strategy considering the input frequency, introduces the power module input frequency, considers the problem of capacitor voltage balance from two dimensions, meets the requirement of direct current voltage, ensures that the power module has equal service life, and reduces the equipment maintenance period. .
In order to achieve the purpose, the technical scheme of the invention is as follows:
a power module capacitance-voltage balancing strategy that accounts for plunge frequency, comprising:
after the valve control system receives the bridge arm voltage modulation wave, the number N of the power modules needing to be input is calculated according to a nearest level approximation methodon；
If N is presentonIf the power module is equal to 0, all power modules are cut off; if N is presentonEqual to the total number N of power modules in a single bridge armSMIf so, all power modules are put in, and the frequency of the newly put power modules is increased by 1;
if 0 < Non＜NSMThe number N of power modules input in the previous periodon_oldSubtracting to obtain a difference value Ndiff；
When N is presentdiffWhen the current is greater than 0, if the bridge arm current iarmIf > 0, N is added from the power module in the cut-off statediffThe power module with the minimum product of the capacitor voltage and the input frequency is added with 1; otherwise, N is addeddiff Adding 1 to the frequency of the power module with the highest capacitor voltage;
when N is presentdiffWhen the voltage is equal to 0, the voltage difference value of the power module is △ UmaxGreater than reference value △ Umax_refSelecting the module with the highest and lowest capacitor voltage from the switched-on and switched-off power modules for switching, and adding 1 to the input frequency of the newly input power module; otherwise, keeping unchanged;
when N is presentdiffIf < 0, if bridge arm current iarmIf > 0, then the power module in the input state is cut off | NdiffThe power module with the largest product of the voltage of | capacitors and the input frequency; otherwise, excise | NdiffAnd | power modules with lowest capacitor voltage.
Compared with the prior art, the invention has the beneficial effects that:
when realizing power module capacitance voltage balance control, the two important parameter indexes of power module input frequency and capacitance voltage size are considered comprehensively, and when the direct current voltage requirement is met, the power module obtains equal service life, and the equipment maintenance period is reduced.
Drawings
FIG. 1 is a MMC modular multilevel converter topology;
FIG. 2 is a logic diagram of a current capacitor voltage balance control strategy;
fig. 3 is a logic diagram of the capacitor voltage balance control strategy of the present invention considering the input frequency.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Referring to fig. 3, the power module capacitance-voltage balancing strategy considering the input frequency of the invention mainly includes:
after the valve control system receives the bridge arm voltage modulation wave, the number N of the power modules needing to be input is calculated according to a nearest level approximation methodon；
If N is presentonIf the power module is equal to 0, all power modules are cut off; if N is presentonEqual to the total number N of power modules in a single bridge armSMIf so, all power modules are put in, and the frequency of the newly put power modules is increased by 1;
if 0 < Non＜NSMThe number N of power modules input in the previous periodon_oldSubtracting to obtain a difference value Ndiff；
When N is presentdiffWhen the current is greater than 0, if the bridge arm current iarmIf > 0, N is added from the power module in the cut-off statediffThe power module with the minimum product of the capacitor voltage and the input frequency is added with 1; otherwise, N is addeddiff Adding 1 to the frequency of the power module with the highest capacitor voltage;
when N is presentdiffWhen the voltage is equal to 0, the voltage difference value of the power module is △ UmaxGreater than reference value △ Umax_refSelecting the module with the highest and lowest capacitor voltage from the switched-on and switched-off power modules for switching, and adding 1 to the input frequency of the newly input power module; otherwise, keeping unchanged;
when N is presentdiffIf < 0, if bridge arm current iarmIf > 0, then the power module in the input state is cut off | NdiffThe power module with the largest product of the voltage of | capacitors and the input frequency; otherwise, excise | NdiffAnd | power modules with lowest capacitor voltage.
It can be seen from the above that, after the valve control system of the present invention receives the bridge arm voltage modulation wave, the number of the power modules required to be input in the period is calculated according to the magnitude of the capacitance voltage of the power module, and is compared with 0, and the total number N of the bridge arm power modulesSMThe number N of power modules put into the previous periodon_oldAnd comparing, referring to whether the bridge arm current is charged or discharged, and finally determining the input power module by combining the input frequency. The invention is mainly characterized in that:
1. when realizing power module capacitance voltage balance control, the two important parameter indexes of power module input frequency and capacitance voltage size are considered comprehensively, and when the direct current voltage requirement is met, the power module obtains equal service life, and the equipment maintenance period is reduced.
2. In the following cases, the power module is directly put into operation and its frequency is increased by 1:
(1) the number of power modules to be input is equal to the total number of bridge arm power modules;
(2) the number of power modules required to be put into the cycle is larger than that of the previous cycle, and the bridge arm current discharges the power modules;
(3) the number of power modules required to be put into the cycle is equal to the previous cycle, the voltage difference value of the power modules is larger than the difference reference value, and the modules with the highest and lowest capacitor voltages in the switching-on and switching-off sub-modules need to be switched;
3. considering the product of the capacitor voltage and the input frequency, and adding 1 to the newly input power module frequency:
(1) the number of power modules required to be put into the cycle is larger than that of the previous cycle, and bridge arm current charges the power modules;
(2) the number of the power modules required to be put into the cycle is smaller than that of the previous cycle, and the bridge arm current charges the power modules.
The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention accordingly, and not to limit the protection scope of the present invention accordingly. All equivalent changes or modifications made in accordance with the spirit of the present disclosure are intended to be covered by the scope of the present disclosure.

Claims (1)

1. A power module capacitor voltage balance strategy considering input frequency is characterized in that: the method comprises the following steps:
after the valve control system receives the bridge arm voltage modulation wave, the number N of the power modules needing to be input is calculated according to a nearest level approximation methodon；
If N is presentonIf the power module is equal to 0, all power modules are cut off; if N is presentonEqual to the total number N of power modules in a single bridge armSMIf so, all power modules are put in, and the frequency of the newly put power modules is increased by 1;
if 0 < Non＜NSMThe number N of power modules input in the previous periodon_oldSubtracting to obtain a difference value Ndiff；
When N is presentdiffWhen the current is greater than 0, if the bridge arm current iarmIf > 0, N is added from the power module in the cut-off statediffThe power module with the minimum product of the capacitor voltage and the input frequency is added with 1; otherwise, N is addeddiffAdding 1 to the frequency of the power module with the highest capacitor voltage;
when N is presentdiffWhen the voltage is equal to 0, the voltage difference value of the power module is △ UmaxGreater than reference value △ Umax_refSelecting the module with the highest and lowest capacitor voltage from the switched-on and switched-off power modules for switching, and adding 1 to the input frequency of the newly input power module; otherwise, keeping unchanged;
when N is presentdiffIf < 0, if bridge arm current iarmIf > 0, then the power module in the input state is cut off | NdiffThe power module with the largest product of the voltage of | capacitors and the input frequency; otherwise, excise | NdiffAnd | power modules with lowest capacitor voltage.
CN201911000413.9A 2019-10-21 2019-10-21 Power module capacitor voltage balance strategy considering input frequency Active CN110768555B (en)

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CN112083861B (en) * 2020-09-07 2021-12-10 中国南方电网有限责任公司超高压输电公司天生桥局 Flexible direct-current valve control information acquisition and judgment device and information acquisition and judgment method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101860203A (en) * 2010-05-28 2010-10-13 浙江大学 Optimal pressure equalizing control method of modular multilevel converter type direct current transmission system
CN105790619A (en) * 2016-01-07 2016-07-20 江苏省电力公司电力科学研究院 Power-adaption capacitance-voltage balance control method for MMC sub-modules

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101860203A (en) * 2010-05-28 2010-10-13 浙江大学 Optimal pressure equalizing control method of modular multilevel converter type direct current transmission system
CN105790619A (en) * 2016-01-07 2016-07-20 江苏省电力公司电力科学研究院 Power-adaption capacitance-voltage balance control method for MMC sub-modules

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
基于排序算法的MMC电容电压均衡策略对比研究;王坤等;《电力建设》;20171130;第38卷(第11期);第9-18页 *

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