CN110994947A - Voltage-sharing control method of modular multilevel converter - Google Patents
Voltage-sharing control method of modular multilevel converter Download PDFInfo
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- CN110994947A CN110994947A CN201911079707.5A CN201911079707A CN110994947A CN 110994947 A CN110994947 A CN 110994947A CN 201911079707 A CN201911079707 A CN 201911079707A CN 110994947 A CN110994947 A CN 110994947A
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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Abstract
The invention discloses a voltage-sharing control method of a modular multilevel converter, which comprises the steps of calculating the number of submodules input by a system at any moment through single carrier modulation, and collecting the capacitance voltage value and the bridge arm current value of each submodule at the moment; taking the magnitude relation between the actual value of the sub-module capacitor voltage and the absolute value of the difference value of the rated value of the actual value and the allowable fluctuation value of the sub-module capacitor voltage as a judgment condition for judging whether to perform sequencing or not; and distributing pulses to the corresponding sub-modules according to the sequencing result and the current flow direction of the bridge arm. The control strategy of the invention ensures that the capacitor voltage of each submodule can be stabilized near the rated value, and simultaneously reduces the switching loss of the system; the sorting algorithm has simple logic, high speed and good stability, and is suitable for engineering application.
Description
Technical Field
The invention belongs to the field of power systems, and particularly relates to a voltage-sharing strategy of a Modular Multilevel Converter (MMC), which is suitable for occasions such as high-voltage direct current (HVDC) transmission, Flexible Alternating Current Transmission (FACTS) transmission and the like.
Background
With the rapid development of power electronic technology, multilevel converters are widely applied in the fields of high-voltage direct-current transmission, flexible alternating-current transmission and electric transmission. The modular multilevel converter has a series of advantages of a common direct current bus, a high modular structure, good output characteristics, low switching frequency and the like, and becomes a hot spot for research of domestic and foreign scholars once being provided.
At present, research aiming at related technologies of the MMC mainly focuses on the aspect of control strategies, wherein balance control of capacitance and voltage of a submodule of the MMC is one of the important difficulties in realizing the MMC application. The traditional voltage-sharing strategy adopts multi-carrier modulation, requires triangular carriers equal to the number of sub-modules, and consumes larger software and hardware resources when the number of the sub-modules is larger; in addition, the traditional voltage-sharing strategy needs to sequence the capacitor voltages of all the submodules in real time without arranging a sequencing judgment condition, so that the switching state of the submodules can be changed after each sequencing, the IGBT is inevitably turned on and off frequently, and unnecessary switching loss is brought to a system, which is unwilling to see in practical engineering application.
Disclosure of Invention
The invention aims to design a voltage-sharing strategy of a modular multilevel converter, which only needs one triangular carrier wave in a modulation mode and is independent of the number of sub-modules of a system; the switching frequency of the IGBT is reduced and the switching loss of the system is reduced while the capacitor voltage of each submodule of the MMC can be ensured to be stabilized near the rated value; and a sequencing algorithm with simple logic, high speed and high stability is adopted for sequencing.
In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problem is as follows: a voltage-sharing control method of a modular multilevel converter only needs to modulate and calculate the number of submodules put into a bridge arm at any moment by a triangular carrier according to the number of the submodules, and collects the capacitance voltage value, the bridge arm current value and the number of the submodules at the moment; setting the allowable fluctuation value of the sub-module capacitor voltage as 3% of the rated value of the sub-module capacitor voltage, taking the magnitude relation between the actual value of the sub-module capacitor voltage and the difference value of the rated value of the sub-module capacitor voltage and the allowable fluctuation value of the sub-module capacitor voltage as a judgment condition, and sorting by adopting an insertion sorting method; and distributing pulses to the corresponding sub-modules according to the sequencing result and the current flow direction of the bridge arm.
According to the voltage-sharing control method of the modular multilevel converter, when the voltage values U of all sub-module capacitorsci(i =1 to n) all satisfy | Uci-Uc rating|＜3% Uc ratingAnd directly performing reordering according to the result of the last sequencing without re-sequencing, wherein the switching state of the sub-modules is unchanged, and the IGBT does not act.
According to the voltage-sharing control method of the modular multilevel converter, if the voltage value U of the sub-module capacitor existsci(i =1 to n) does not satisfy | Uci-Uc rating|＜3% Uc ratingIn the process, the capacitor capacitance voltage values of n sub-modules in the bridge arm are sequenced by adopting an insertion sequencing algorithm to obtain a sequencing result Uc1>Uc2>…>UcnAnd Uc1～UcnMapping relation with each sub-module;
when bridge arm current ipaWhen greater than 0, for Uc(n-npa+1)～UcnThe mapped submodule sends out a '1' pulse to Uc1～Uc(n-npa)The mapped sub-module sends out a '0' pulse;
when bridge arm current ipaWhen less than 0, for Uc1～Uc（npa）The mapped submodule sends out a '1' pulse to Uc（npa+1）～UcnThe mapped sub-module sends out a "0" pulse.
According to the insertion ordering method, all the arrays to be ordered are divided into an ordered area and an unordered area, only the first number is firstly assigned to the ordered area, the remainder is assigned to the unordered area, then the first number of the unordered area is inserted into the ordered array according to the size sequence of the first number, the ordered area with the new number inserted is still maintained to be from large to small or from small to large, and the ordering is finished until all the numbers enter the ordered area.
The invention has the beneficial effects that: the modulation mode only needs one triangular carrier, and is irrelevant to the number of system sub-modules, so that software and hardware resources are greatly saved; the voltage fluctuation range of the sub-module capacitor is controlled, meanwhile, unnecessary action of the sub-module IGBT is avoided, and the switching loss of the system is reduced; the sequencing is performed by using an insertion sequencing algorithm, and the method has the advantages of simple logic, high speed and good stability.
Drawings
FIG. 1 is a flow chart of a voltage sharing control method of the present invention;
FIG. 2 is a single carrier modulation flow chart of the present invention;
FIG. 3 is a flow chart of the insert ordering algorithm of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
The invention discloses a voltage-sharing control method of a Modular Multilevel Converter (MMC). No matter the number of submodules, the number of submodules put into a bridge arm at any moment is calculated by modulating a triangular carrier wave, and the capacitance voltage value, the bridge arm current value and the number of the submodules at the moment are collected; setting the allowable fluctuation value of the sub-module capacitor voltage as 3% of the rated value of the sub-module capacitor voltage, taking the magnitude relation between the actual value of the sub-module capacitor voltage and the difference value of the rated value of the sub-module capacitor voltage and the allowable fluctuation value of the sub-module capacitor voltage as a judgment condition, and sorting by adopting an insertion sorting method; and distributing pulses to the corresponding sub-modules according to the sequencing result and the current flow direction of the bridge arm.
The modulation mode of the voltage-sharing strategy of the invention adopts single carrier modulation, only one triangular carrier is needed no matter the number of the system submodules, and compared with the traditional multi-carrier modulation, the invention saves software and hardware resources; the sequencing judgment condition is introduced, so that the problem that the IGBT of the sub-module is frequently switched on and off due to the traditional real-time sequencing is effectively avoided, and the switching frequency of the device and the switching loss of a system are remarkably reduced; the sequencing algorithm uses an insertion sequencing method, has simple logic, high speed and good stability, and is suitable for practical engineering application.
The specific implementation flow of the voltage-sharing strategy of the modular multilevel converter is shown in fig. 1, the algorithm is simple, the voltage fluctuation range of the sub-module capacitor is controlled, meanwhile, unnecessary actions of the sub-module IGBT are avoided, and the switching loss of the system is reduced.
A single carrier modulation flow diagram is shown in figure 2,
to represent
Rounding is carried out by a triangular carrier Tri and a triangular carrier Tri with a value range of 0-1
Comparing the result with
Adding to obtain the number of submodules put into the MMC bridge arm at any moment
。
Calculating the number n of submodules put into the MMC bridge arm at any momentpaThen, for each sub-module capacitance voltage value, bridge arm current value and n at the momentpaCollecting, and setting sequencing judgment condition-whether the capacitance voltage values U of all the submodules areci(i =1 to n) all satisfy an inequality | Uci-Uc rating|＜3% Uc rating。
If the capacitance voltage values of the submodules do not meet the inequality, sorting the capacitance voltage values of the n submodules in the bridge arm by adopting an insertion sorting algorithm shown in fig. 3 to obtain a sorting result Uc1>Uc2>…>UcnAnd Uc1～UcnAnd mapping relation with each submodule.
When bridge arm current ipaWhen greater than 0, for Uc(n-npa+1)～UcnThe mapped submodule sends out a '1' pulse to Uc1～Uc(n-npa)The mapped sub-module sends out a "0" pulse. When bridge arm current ipaWhen less than 0, for Uc1～Uc（npa）The mapped submodule sends out a '1' pulse to Uc（npa+1）～UcnThe mapped sub-module sends out a "0" pulse. If the capacitance voltage values of all the sub-modules meet the inequality, sequencing is not needed, and pulses are directly sent to the corresponding sub-modules according to the sequencing result of the previous time.
The flow of the insert sorting algorithm is shown in fig. 1, the insert sorting method is to divide all the arrays to be sorted into two regions of sorted and unsorted regions, only the first number is sorted in the sorted region at first, the remainder is sorted in the unsorted region, then the first number of the unsorted region is inserted into the sorted arrays according to the size sequence of the first number, so that the sorted regions after inserting new numbers still maintain the property of descending from large to small or descending from small to large, and so on until the sorting is finished after all the numbers enter the sorted regions.
The above-described embodiments are merely illustrative of the principles and effects of the present invention, and some embodiments may be applied, and it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the inventive concept of the present invention, and these embodiments are within the scope of the present invention.
Claims (4)
1. A voltage-sharing control method of a modular multilevel converter is characterized by comprising the following steps: calculating the number of submodules put into the bridge arm at any moment through triangular carrier modulation, and collecting the capacitance voltage value, the bridge arm current value and the number of the submodules at the moment; setting the allowable fluctuation value of the sub-module capacitor voltage as 3% of the rated value of the sub-module capacitor voltage, taking the magnitude relation between the actual value of the sub-module capacitor voltage and the difference value of the rated value of the sub-module capacitor voltage and the allowable fluctuation value of the sub-module capacitor voltage as a judgment condition, and sorting by adopting an insertion sorting method; and distributing pulses to the corresponding sub-modules according to the sequencing result and the current flow direction of the bridge arm.
2. The voltage-sharing control method of the modular multilevel converter according to claim 1, wherein the voltage-sharing control method is performed when all the sub-module capacitor voltage values are Uci(i =1 to n) all satisfy | Uci-Uc rating|＜3% Uc ratingAnd directly performing reordering according to the result of the last sequencing without re-sequencing, wherein the switching state of the sub-modules is unchanged, and the IGBT does not act.
3. The voltage-sharing control method of the modular multilevel converter according to claim 2, wherein the voltage value of the sub-module capacitor, if any, is Uci(i =1 to n) does not satisfy | Uci-Uc rating|＜3% Uc ratingIn the process, the capacitor capacitance voltage values of n sub-modules in the bridge arm are sequenced by adopting an insertion sequencing algorithm to obtain a sequencing result Uc1>Uc2>…>UcnAnd Uc1～UcnMapping relation with each sub-module;
when bridge arm current ipaWhen greater than 0, for Uc(n-npa+1)～UcnThe mapped submodule sends out a '1' pulse to Uc1～Uc(n-npa)The mapped sub-module sends out a '0' pulse;
when bridge arm current ipaWhen less than 0, for Uc1～Uc（npa）The mapped submodule sends out a '1' pulse to Uc（npa+1）～UcnThe mapped sub-module sends out a "0" pulse.
4. The voltage-sharing control method for the modular multilevel converter according to claim 3, wherein the insertion sorting method is to divide all the arrays to be sorted into two regions of sorted and unsorted regions, only the first number is sorted in the sorted region at the beginning, the remainder is sorted in the unsorted region, and then the first number of the unsorted region is inserted into the sorted arrays according to the size sequence of the first number, so that the sorted regions after inserting the new number still maintain the property of being from large to small or from small to large, and so on until all the numbers enter the sorted regions and then the sorting is finished.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104038052A (en) * | 2014-06-23 | 2014-09-10 | 上海交通大学 | Quick voltage balance control method for modular multilevel converter |
| CN104158419A (en) * | 2014-08-04 | 2014-11-19 | 浙江大学 | Method for balancing capacitor voltage of modularization multilevel converter |
| CN105656330A (en) * | 2015-04-03 | 2016-06-08 | 华北电力大学 | Capacitance voltage balancing strategy suitable for high level modular multilevel converter |
| CN105897025A (en) * | 2016-05-05 | 2016-08-24 | 上海电机学院 | Modular multilevel converter sub-module voltage equalization method |
| CN109713923A (en) * | 2018-12-10 | 2019-05-03 | 西安理工大学 | A kind of MMC submodule capacitor voltage dynamic equalization control method of optimization |
-
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- 2019-11-07 CN CN201911079707.5A patent/CN110994947A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104038052A (en) * | 2014-06-23 | 2014-09-10 | 上海交通大学 | Quick voltage balance control method for modular multilevel converter |
| CN104158419A (en) * | 2014-08-04 | 2014-11-19 | 浙江大学 | Method for balancing capacitor voltage of modularization multilevel converter |
| CN105656330A (en) * | 2015-04-03 | 2016-06-08 | 华北电力大学 | Capacitance voltage balancing strategy suitable for high level modular multilevel converter |
| CN105897025A (en) * | 2016-05-05 | 2016-08-24 | 上海电机学院 | Modular multilevel converter sub-module voltage equalization method |
| CN109713923A (en) * | 2018-12-10 | 2019-05-03 | 西安理工大学 | A kind of MMC submodule capacitor voltage dynamic equalization control method of optimization |
Non-Patent Citations (2)
| Title |
|---|
| 于翔: ""模块化多电平换流器（MMC）电容均压控制研究"", 《中国优秀硕士学位论文全文数据库 工程科技II辑》 * |
| 高戈，等: ""基于改进的子模块电容电压均衡的MMC环流抑制"", 《电力电子技术》 * |
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