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WO2024067836A1 - 一种三相四桥臂三电平逆变器的电压调节方法 - Google Patents

一种三相四桥臂三电平逆变器的电压调节方法 Download PDF

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Publication number
WO2024067836A1
WO2024067836A1 PCT/CN2023/122773 CN2023122773W WO2024067836A1 WO 2024067836 A1 WO2024067836 A1 WO 2024067836A1 CN 2023122773 W CN2023122773 W CN 2023122773W WO 2024067836 A1 WO2024067836 A1 WO 2024067836A1
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Prior art keywords
vector
voltage
bridge arm
voltage vector
bridge
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PCT/CN2023/122773
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English (en)
French (fr)
Inventor
张欣
陈赢
周旭
张玉林
郭斌
殷晔平
杨博
Original Assignee
上海正泰电源系统有限公司
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Priority to EP23871060.2A priority Critical patent/EP4529015A1/en
Publication of WO2024067836A1 publication Critical patent/WO2024067836A1/zh

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Classifications

    • 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
    • H02M7/487—Neutral point clamped inverters
    • 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
    • H02M7/4833—Capacitor voltage balancing
    • 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
    • H02M7/53871—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 with automatic control of output voltage or current
    • 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
    • H02M7/53871—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 with automatic control of output voltage or current
    • H02M7/53875—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 with automatic control of output voltage or current with analogue control of three-phase output
    • H02M7/53876—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 with automatic control of output voltage or current with analogue control of three-phase output based on synthesising a desired voltage vector via the selection of appropriate fundamental voltage vectors, and corresponding dwelling times
    • 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
    • H02M7/539—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 with automatic control of output wave form or frequency
    • H02M7/5395—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 with automatic control of output wave form or frequency by pulse-width modulation

Definitions

  • the present application relates to the field of electronic technology, and in particular to a voltage regulation method for a three-phase four-bridge-arm three-level inverter.
  • Multi-level inverters have received much attention in medium and high voltage power applications, and different circuit topologies and inverter control methods have been proposed. Multi-level inverters have gradually entered the practical stage, especially in my country, where the market demand is relatively large. With people's increasingly strong awareness of power saving and market interest orientation, my country's potential market demand will inevitably transform into actual market demand, thus giving medium voltage and high power inverter products a broad market prospect.
  • the midpoint balance problem of the DC side capacitor Because of the topological structure of the multi-level inverter, there is a capacitor voltage imbalance problem caused by the imbalance of charging and discharging of the DC voltage divider capacitor in the diode clamp type. The reason for the change in the midpoint capacitor voltage is mainly affected by the current flowing into the midpoint of each phase. The imbalance of the midpoint capacitor voltage will cause the output load voltage waveform to produce DC bias or waveform distortion, so the midpoint balance problem must be solved.
  • the embodiment of the present application provides a voltage regulation method of a three-phase four-bridge-arm three-level inverter, which is used to improve/solve the problem of unbalanced midpoint voltage in a multi-level inverter in the related art.
  • the present application provides a voltage regulation method for a three-phase four-bridge-arm three-level inverter, the method comprising: determining a voltage vector corresponding to a three-phase voltage; constructing a spatial polyhedron controllable region based on an abc three-dimensional coordinate system and the voltage vector; positioning a preset reference vector in multiple sub-regions of the spatial polyhedron controllable region to generate a reference voltage vector corresponding to the reference vector, the reference voltage vector being used to control the output state of the corresponding four bridge arms; sorting the reference voltage vectors under a modulation strategy of reducing the zero-level output state; and performing a control operation according to the sorted reference voltage vectors and the corresponding effects. time, generating a switching pulse sequence of the bridge arm to adjust the midpoint voltage of the three-phase four-bridge-arm three-level inverter.
  • determining a voltage vector corresponding to the three-phase voltage includes: determining the voltage vector corresponding to the three-phase voltage according to an output state of a bridge arm, where the output state includes a high level, a zero level, and a low level.
  • determining the voltage vector corresponding to the three-phase voltage according to the output state of the bridge arm includes: determining the voltage vector corresponding to the three-phase voltage using the following formula:
  • U AN represents the voltage vector of the A bridge arm relative to the N bridge arm
  • U BN represents the voltage vector of the B bridge arm relative to the N bridge arm
  • U CN represents the voltage vector of the C bridge arm relative to the N bridge arm.
  • Sa , Sb , Sc and Sn are the output states of the A, B, C and N bridge arms of the three-phase four-bridge-arm three-level inverter respectively
  • Udc represents the DC side power supply voltage.
  • a spatial polyhedron controllable area is constructed, including: standardizing the voltage vector; introducing the standardized voltage vector into the abc three-dimensional coordinate system to construct the spatial polyhedron controllable area.
  • the voltage vector is normalized, including: normalizing the voltage vector using the following formula:
  • the spatial polyhedron controllable region is a dodecahedron controllable region
  • the dodecahedron controllable region includes three cube regions constructed by standardized voltage vectors and a plurality of regions fitted on the three cubes. Six imaginary cube areas outside the area.
  • a preset reference vector is positioned in multiple sub-regions of a controllable region of a spatial polyhedron to generate a reference voltage vector corresponding to the reference vector, including: positioning the preset reference vector in a cubic region of multiple sub-regions of the controllable region of the spatial polyhedron; positioning the preset reference vector in a tetrahedron region of multiple sub-regions of the controllable region of the spatial polyhedron based on the positioning result of the cubic region; and generating a reference voltage vector corresponding to the reference vector according to the final positioning result.
  • positioning a preset reference vector in a cube region of a plurality of sub-regions of a controllable region of a spatial polyhedron includes: selecting a cube where the reference origin coordinates are located in the controllable region of the spatial polyhedron based on the reference origin coordinates rounded off by the reference vector; wherein the reference origin coordinate point is:
  • a preset reference vector is positioned in a tetrahedral area of multiple sub-areas of a controllable area of a spatial polyhedron, including: dividing the positioned target cube into three 45° sections using the original coordinates corresponding to the reference vector as a reference point, calculating the distances of the three sections with the reference origin coordinates as the center, and determining the tetrahedral position of the reference vector, wherein the three 45° sections include a 45° section passing through the a-b axis, a 45° section passing through the origin, and a 45° section passing through the a-c axis.
  • reference voltage vectors are sorted, including: determining a synthesis order of reference voltage vectors in a controllable region of a spatial polyhedron; and adjusting the order of reference voltage vectors with the goal of reducing a midpoint current flowing into each bridge arm.
  • generating a switch pulse sequence of a bridge arm according to the sorted reference voltage vectors and the corresponding action time includes: determining a duty cycle corresponding to the reference voltage vector using the following formula:
  • a switching pulse sequence of a bridge arm is generated according to the sorted reference voltage vectors and the corresponding action time, including: sorting the action time of the reference voltage vectors according to the arrangement of the sorted reference voltage vectors; allocating the sorted action time into nine segments; the nine-segment allocation is as follows: the first segment, the fifth segment, and the ninth segment of the nine-segment vector are allocated to the same time period, the first segment and the ninth segment occupy 1/4 respectively, the fifth segment occupies 1/2, and the remaining six segments each occupy 1/2 of the corresponding time period according to symmetry; the state of the four bridge arms is determined according to the voltage vector, and four corresponding switch states are allocated to each state to form a pulse sequence.
  • the voltage regulation method of the three-phase four-bridge-arm three-level inverter includes: determining the voltage vector corresponding to the three-phase voltage; constructing a spatial polyhedron controllable area based on the abc three-dimensional coordinate system and the voltage vector; locating the preset reference vector in multiple sub-areas of the spatial polyhedron controllable area to generate a reference voltage vector corresponding to the reference vector, and the reference voltage vector is used to control the output state of the corresponding four bridge arms; under the modulation strategy of reducing the zero-level output state, the reference voltage vector is sorted; according to the sorted reference voltage vector and the corresponding action time, a switch pulse sequence of the bridge arm is generated to adjust the midpoint voltage of the three-phase four-bridge-arm three-level inverter.
  • Adopt a modulation strategy with the goal of reducing the current flowing into the midpoint of each bridge arm, the original reference voltage vector is sequentially modified to offset the zero-level output state that affects the midpoint voltage balance.
  • FIG1 is a schematic structural diagram of a three-phase four-bridge-arm three-level inverter provided by the present application
  • FIG2 is a flow chart of an embodiment of a voltage regulation method for a three-phase four-bridge-arm three-level inverter provided by the present application;
  • FIG3 is a schematic diagram of a flow chart of step 22 in one embodiment
  • FIG4 is a schematic diagram of a controllable area of a spatial polyhedron provided in the present application.
  • FIG5 is a schematic diagram of a flow chart of step 23 in one embodiment
  • FIG6 is a schematic diagram of a process of cube positioning provided by the present application.
  • FIG7 is a schematic diagram of the process of tetrahedron positioning provided by the present application.
  • FIG8 is a schematic diagram of a flow chart of step 25 in one embodiment
  • FIG9 is a schematic diagram of a nine-segment time allocation method provided by the present application.
  • FIG10 is a midpoint diagram under a balanced load condition provided by the present application.
  • FIG. 11 is a midpoint diagram of the actual load condition after balancing by the voltage regulation method of the present application.
  • first and second are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the terms “first” and “second” are limited to The features of a can include one or more of the features explicitly or implicitly. In the description of this application, the meaning of “plurality” is two or more, unless otherwise clearly and specifically defined.
  • a and/or B includes the following three combinations: A only, B only, and a combination of A and B.
  • FIG. 1 is a structural schematic diagram of a three-phase four-bridge-arm three-level inverter provided by the present application.
  • Udc DC side voltage source
  • FIG. 2 is a flow chart of an embodiment of a voltage regulation method for a three-phase four-bridge-arm three-level inverter provided by the present application.
  • the method includes:
  • Step 21 Determine the voltage vector corresponding to the three-phase voltage.
  • the voltage vector corresponding to the three-phase voltage is determined according to the output state of the bridge arm, and the output state includes a high level, a zero level and a low level.
  • U AN represents the voltage vector of bridge arm A relative to bridge arm N
  • U BN represents the voltage vector of bridge arm B relative to bridge arm N
  • U CN represents the voltage vector of bridge arm C relative to bridge arm N
  • Sa , Sb , Sc , Sn are the output states of bridge arms A, B, C, and N of the three-phase four-arm three-level inverter respectively
  • U dc represents the DC side power supply voltage
  • Step 22 Based on the abc three-dimensional coordinate system and the voltage vector, construct a spatial polyhedron controllable area.
  • the spatial polyhedron controllable region includes a plurality of cubic sub-regions and a plurality of tetrahedral sub-regions.
  • FIG. 3 is a flow chart of step 22 in an embodiment, and step 22 may include:
  • Step 221 normalize the voltage vector.
  • the voltage vector is normalized using the following formula:
  • Step 222 Introduce the standardized voltage vector into the abc three-dimensional coordinate system to construct a spatial polyhedron controllable area.
  • FIG4 is a schematic diagram of a controllable region of a spatial polyhedron provided by the present application. After the quantity is standardized, the standardized voltage vector is introduced into the abc three-dimensional coordinate system to construct a dodecahedron controllable area.
  • controllable area of the spatial polyhedron includes three large cubes and six imaginary cubes.
  • the imaginary cube is a control area with a modulation ratio range of 0.866 to 1, and the controllable area is translated to the positive direction of the abc coordinate system to facilitate unified analysis and calculation.
  • Step 23 In the multiple sub-areas of the controllable area of the spatial polyhedron, a preset reference vector is positioned to generate a reference voltage vector corresponding to the reference vector, and the reference voltage vector is used to control the output states of the corresponding four bridge arms.
  • a preset reference vector is used for positioning to generate a reference voltage vector corresponding to the reference vector. Positioning can be performed in multiple cubic regions first, and then positioning can be performed in multiple tetrahedral regions based on the positioning results of the cubic regions to obtain the final positioning results. As shown in FIG5 , FIG5 is a flow chart of step 23 in one embodiment, and step 23 may include:
  • Step 231 Positioning a preset reference vector in a cubic area of a plurality of sub-areas of a controllable area of a spatial polyhedron.
  • a cube where the reference origin coordinates are located is selected in the controllable area of the spatial polyhedron
  • the reference original coordinate point is:
  • FIG. 6 is a schematic diagram of the process of cube positioning provided in the present application.
  • the above formula is used to calculate the reference original coordinate point (a, b, c), and then the logical sequence of FIG6 is used to make a judgment:
  • the selected cube is cube1;
  • the selected cube is cube4;
  • the selected cube is cube3;
  • the selected cube is cube6;
  • the selected cube is cube27;
  • the selected cube is cube2;
  • the selected cube is cube5;
  • the selected cube is cube7;
  • the selected cube is cube8;
  • the selected cube is cube11;
  • the selected cube is cube26;
  • the selected cube is cube10;
  • the selected cube is cube13;
  • the selected cube is cube28;
  • the selected cube is cube25;
  • the selected cube is cube9;
  • the selected cube is cube12;
  • the selected cube is cube23;
  • the selected cube is cube14;
  • the selected cube is cube15;
  • the selected cube is cube18;
  • the selected cube is cube17;
  • the selected cube is cube20;
  • the selected cube is cube24;
  • the selected cube is cube16;
  • the selected cube is cube19;
  • the selected cube is cube21;
  • the selected cube is cube22.
  • Step 232 Based on the positioning result of the cube area, the preset reference vector is positioned in the tetrahedron area of the multiple sub-areas of the spatial polyhedron controllable area.
  • the target cube to be positioned is divided into three 45° sections with the original coordinates corresponding to the reference vector as the reference point.
  • the distances of the three sections are calculated with the reference origin coordinates as the center to determine the position of the tetrahedron where the reference vector is located.
  • the three 45° sections include the a-b axis 45° section passing through the origin, the c-b axis 45° section and the a-c axis 45° section.
  • FIG. 7 is a schematic diagram of the process of tetrahedron positioning provided by the present application.
  • the reference original coordinate point (a, b, c) and the reference vector (u an , u b n , u c n ) are calculated using the above formula, and then the logical sequence of FIG. 7 is used for determination:
  • Step 233 Generate a reference voltage vector corresponding to the reference vector according to the final positioning result.
  • Step 24 Sequencing the reference voltage vector under a modulation strategy that reduces the zero-level output state.
  • step 24 can be specifically as follows: determining the synthesis order of the reference voltage vectors in the controllable area of the spatial polyhedron; adjusting the order of the reference voltage vectors with the goal of reducing the current flowing into the midpoint of each bridge arm.
  • the new vector arrangement method is (the four reference voltage vectors of a tetrahedron are V1-V4):
  • the order of reference voltage vectors for the tetrahedrons in cubes 1-11 is: V4, V3, V2, V1;
  • the reference voltage vector sequence for cubes 12-22 is: V1, V2, V3, V4;
  • the order of the reference voltage vectors of the tetrahedrons in the imaginary cubes No. 23, 25, and 27 is: V2, V3, V4, V1;
  • the order of reference voltage vectors of the tetrahedrons in the imaginary cubes No. 24, 26, and 28 is: V3, V2, V1, V4.
  • Step 25 Generate a switch pulse sequence of the bridge arm according to the sorted reference voltage vectors and the corresponding action time to adjust the midpoint voltage of the three-phase four-bridge-arm three-level inverter.
  • FIG. 8 is a flow chart of step 25 in one embodiment, and step 25 may include:
  • Step 251 Determine the action time corresponding to the reference voltage vector.
  • the duty cycle corresponding to the reference voltage vector is determined using the following formula:
  • d1-4 are the duty cycle of the reference voltage vector.
  • the voltage vectors are V1-V4 and the corresponding action time is T1-T4, and the order of the action time is consistent with the order of the above-mentioned reference voltage vectors.
  • Step 252 Generate a switch pulse sequence of the bridge arm according to the sorted reference voltage vectors and the corresponding action times.
  • the action time of the reference voltage vectors is sorted; the sorted action time is distributed in nine sections; the nine-section distribution is as follows: the first section, the fifth section and the ninth section of the nine-section vector are allocated the same time period, the first section and the ninth section respectively occupy 1/4, the fifth section occupies 1/2, and the remaining six sections each occupy 1/2 of the corresponding time period according to symmetry (i.e., T x1 /4, T x2 /2, T x3 /2, T x4 /2, T x1 /2, T x4 /2, T x3 /2, T x2 /2, T x1 /4); the state of the four bridge arms is determined according to the voltage vector, and four corresponding switch states are allocated to each state to form a pulse sequence.
  • Figure 9 is a schematic diagram of the nine-section time distribution method provided by the present application.
  • the voltage regulation method of the three-phase four-bridge-arm three-level inverter includes: determining the voltage vector corresponding to the three-phase voltage; constructing a spatial polyhedron controllable area based on the abc three-dimensional coordinate system and the voltage vector, and the spatial polyhedron controllable area includes multiple tetrahedron sub-areas and cube sub-areas; in the multiple sub-areas of the spatial polyhedron controllable area, positioning the preset reference vector to generate a reference voltage vector corresponding to the reference vector, and the reference voltage vector is used to control the output state of the corresponding four bridge arms; under the modulation strategy of reducing the zero-level output state, sorting the reference voltage vector; according to the sorted reference voltage vector and the corresponding action time, generating a switch pulse sequence of the bridge arm to adjust the midpoint voltage of the three-phase four-bridge-arm three-level inverter.
  • this embodiment has the following beneficial effects:
  • Adopt a modulation strategy with the goal of reducing the current flowing into the midpoint of each bridge arm, the original reference voltage vector is sequentially modified to offset the zero-level output state that affects the midpoint voltage balance.
  • Figure 10 is a midpoint diagram under balanced load conditions provided by the present application
  • Figure 11 is a midpoint diagram under actual load conditions after balancing by the voltage regulation method of the present application.
  • the horizontal axis is time and the vertical axis is voltage.
  • the inverter power in Figure 10 is 5KW
  • the inverter power in Figure 11 is 5KW.
  • the power of the device is 100KW; it can be seen from the figure that the method provided by this embodiment can well maintain the midpoint voltage balance, and after extending the time axis, it can be seen that the operation is very stable.

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Abstract

本发明提供一种三相四桥臂三电平逆变器的电压调节方法，该方法包括：确定三相电压对应的电压矢量；基于abc三维坐标系和所述电压矢量，构建空间多面体可控区域；在所述空间多面体可控区域的多个子区域中，对预设的参考矢量进行定位，以生成所述参考矢量对应的参考电压矢量，所述参考电压矢量用于控制对应四桥臂的输出状态；在减少零电平输出状态的调制策略下，对所述参考电压矢量进行排序；根据排序后的所述参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列，以对所述三相四桥臂三电平逆变器的中点电压进行调节。通过上述方式，能够平衡逆变器的中点电压。

Description

一种三相四桥臂三电平逆变器的电压调节方法 技术领域
本申请涉及电子技术领域，具体涉及一种三相四桥臂三电平逆变器的电压调节方法。
背景技术
随着电子技术的发展，在中高压功率的场合，多电平逆变器受到许多关注，不同的电路拓扑结构以及逆变器的控制方法不断被提出。多电平逆变器已逐步进入实用阶段，特别是我国市场的需求比较大，随着人们节电意识越来越强烈和市场利益导向，我国潜在的市场需求必将转变为实际的市场需求，从而使中压大功率变频器产品具有广阔的市场前景。
在多电平逆变器控制过程中一直都存在的问题：直流侧电容的中点平衡问题，因为多电平逆变器的拓扑结构，在二级管钳位式中存在由直流分压电容充放电不均衡造成的电容电压不平衡问题。中点电容电压变化的原因主要是受每一相流入中点的电流所影响。中点电容电压不平衡会引起输出的负载电压波形产生直流偏置或者波形畸形，所以必须解决中点平衡问题。
发明内容
本申请实施例提供一种三相四桥臂三电平逆变器的电压调节方法，用于改善/解决相关技术中在多电平逆变器中，中点电压不平衡的问题。
本申请提供一种三相四桥臂三电平逆变器的电压调节方法，该所述方法包括：确定三相电压对应的电压矢量；基于abc三维坐标系和所述电压矢量，构建空间多面体可控区域；在所述空间多面体可控区域的多个子区域中，对预设的参考矢量进行定位，以生成所述参考矢量对应的参考电压矢量，所述参考电压矢量用于控制对应四桥臂的输出状态；在减少零电平输出状态的调制策略下，对所述参考电压矢量进行排序；根据排序后的所述参考电压矢量及对应的作用 时间，生成桥臂的开关脉冲序列，以对所述三相四桥臂三电平逆变器的中点电压进行调节。
在一些实施例中，确定三相电压对应的电压矢量，包括：根据桥臂的输出状态，确定三相电压对应的电压矢量，输出状态包括高电平、零电平和低电平。
在一些实施例中，根据桥臂的输出状态，确定三相电压对应的电压矢量，包括：采用以下公式确定三相电压对应的电压矢量：
其中，UAN表示A桥臂相对于N桥臂的电压矢量，UBN表示B桥臂相对于N桥臂的电压矢量，UCN表示C桥臂相对于N桥臂的电压矢量， Sa、Sb、Sc、Sn分别为三相四桥臂三电平逆变器A、B、C、N桥臂的输出状态，Udc表示直流侧电源电压。
在一些实施例中，基于abc三维坐标系和电压矢量，构建空间多面体可控区域，包括：对电压矢量进行标准化处理；将标准化处理后的电压矢量，引入abc三维坐标系中，构建空间多面体可控区域。
在一些实施例中，对电压矢量进行标准化处理，包括：采用以下公式对电压矢量进行标准化处理：
其中，表示标准化后A桥臂相对于N桥臂的电压矢量，表示标准化后B桥臂相对于N桥臂的电压矢量，表示标准化后C桥臂相对于N桥臂的电压矢量。
在一些实施例中，空间多面体可控区域为十二面体可控区域，十二面体可控区域包括由标准化电压矢量构建的三个正方体区域、以及贴合在三个正方体 区域外侧的六个虚构立方体区域。
在一些实施例中，在空间多面体可控区域的多个子区域中，对预设的参考矢量进行定位，以生成参考矢量对应的参考电压矢量，包括：在空间多面体可控区域的多个子区域的立方体区域中，对预设的参考矢量进行定位；基于立方体区域的定位结果，在空间多面体可控区域的多个子区域的四面体区域中，对预设的参考矢量进行定位；根据最终的定位结果，生成参考矢量对应的参考电压矢量。
在一些实施例中，在空间多面体可控区域的多个子区域的立方体区域中，对预设的参考矢量进行定位，包括：基于参考矢量取整后的参考原点坐标，在空间多面体可控区域中选取参考原点坐标所在的立方体；其中，参考原坐标点为：
其中，表示参考矢量的a轴坐标，表示参考矢量的b轴坐标，表示参考矢量的c轴坐标。
在一些实施例中，在空间多面体可控区域的多个子区域的四面体区域中，对预设的参考矢量进行定位，包括：对定位的目标立方体以参考矢量对应的原坐标为参考点，采用三个45°切面进行划分，以参考原点坐标为中心计算三个切面的距离，确定参考矢量所在的四面体位置，三个45°切面包括以过原点的a-b轴45°切面、c-b轴45°切面以及a-c轴45°切面。
在一些实施例中，在减少零电平输出状态的调制策略下，对参考电压矢量进行排序，包括：确定空间多面体可控区域中参考电压矢量的合成顺序；以减小各桥臂流入中点电流为目标，调整参考电压矢量的顺序。
在一些实施例中，根据排序后的参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列，包括：采用以下公式确定参考电压矢量对应的占空比：
将占空比乘以开关周期，得到参考电压矢量对应的作用时间；其中，为参考电压矢量所在的四面体定点坐标，Ts为开关周期，d1-4为参考电压矢量的占空比；根据排序后的参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列。
在一些实施例中，根据排序后的参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列，包括：根据排序后的参考电压矢量的排列方式，对参考电压矢量的作用时间进行排序；将排序后的作用时间进行九段式分配；九段式分配为：九段矢量中的第一段、第五段和第九段分配同一段时间，第一段和第九段分别占1/4，第五段占1/2，剩余六段根据对称性各占对应时间段的1/2；根据电压矢量来确定四桥臂的状态，为每个状态分配对应的四个开关状态，形成脉冲序列。
本申请实施例提供的三相四桥臂三电平逆变器的电压调节方法包括：确定三相电压对应的电压矢量；基于abc三维坐标系和电压矢量，构建空间多面体可控区域；在空间多面体可控区域的多个子区域中，对预设的参考矢量进行定位，以生成参考矢量对应的参考电压矢量，参考电压矢量用于控制对应四桥臂的输出状态；在减少零电平输出状态的调制策略下，对参考电压矢量进行排序；根据排序后的参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列，以对三相四桥臂三电平逆变器的中点电压进行调节。通过上述方式，本实施例具有以下有益效果：
(1)在不增设控制器的条件下，实现了三相四桥臂三电平逆变器中点电压的平衡调节。
(2)引入了六个虚构立方体，保证在参考矢量的位置判断时，减少了传统SVPWM调制方法的多余可控区域，简化了传统SVPWM调制方法的复杂度。
(3)采用调制策略：以减少各个桥臂流入中点电流为目标，对原参考电压矢量进行顺序的改动，从而将影响中点电压平衡的零电平输出状态进行抵消。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述中所 需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是本申请提供的三相四桥臂三电平逆变器的结构示意图；
图2是本申请提供的三相四桥臂三电平逆变器的电压调节方法一实施例的流程示意图；
图3是一实施例中步骤22的流程示意图；
图4为本申请提供的空间多面体可控区域的示意图；
图5是一实施例中步骤23的流程示意图；
图6是本申请提供的立方体定位的流程示意图；
图7是本申请提供的四面体定位的流程示意图；
图8是一实施例中步骤25的流程示意图；
图9是本申请提供的九段式时间分配方法示意图；
图10是本申请提供的平衡负载工况下中点点位图；
图11是本申请通过电压调节方法平衡之后的实际负载工况下的中点点位图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
在本申请的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二” 的特征可以明示或者隐含地包括一个或者更多个所述特征。在本申请的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
“A和/或B”，包括以下三种组合：仅A，仅B，及A和B的组合。
本申请中“适用于”或“被配置为”的使用意味着开放和包容性的语言，其不排除适用于或被配置为执行额外任务或步骤的设备。另外，“基于”的使用意味着开放和包容性，因为“基于”一个或多个所述条件或值的过程、步骤、计算或其他动作在实践中可以基于额外条件或超出所述的值。
在本申请中，“示例性”一词用来表示“用作例子、例证或说明”。本申请中被描述为“示例性”的任何实施例不一定被解释为比其它实施例更优选或更具优势。为了使本领域任何技术人员能够实现和使用本申请，给出了以下描述。在以下描述中，为了解释的目的而列出了细节。应当明白的是，本领域普通技术人员可以认识到，在不使用这些特定细节的情况下也可以实现本申请。在其它实例中，不会对公知的结构和过程进行详细阐述，以避免不必要的细节使本申请的描述变得晦涩。因此，本申请并非旨在限于所示的实施例，而是与符合本申请所公开的原理和特征的最广范围相一致。
如图1所示，图1是本申请提供的三相四桥臂三电平逆变器的结构示意图，三相四桥臂三电平逆变器的拓扑结构包括直流侧电压源Udc，从左到右分别为A桥臂，B桥臂，C桥臂以及N桥臂，每个桥臂分别有四个开关(如IGBT)与两个二极管组成，每个桥臂的输出点为ux(x＝a，b，c，n)，每个桥臂的二极管中点与分裂电容中点n相连接，本申请实施例需要调节的便是分裂电容中点n的电压。
参阅图2，图2是本申请提供的三相四桥臂三电平逆变器的电压调节方法一实施例的流程示意图，该方法包括：
步骤21：确定三相电压对应的电压矢量。
可选地，在一实施例中，根据桥臂的输出状态，确定三相电压对应的电压矢量，输出状态包括高电平、零电平和低电平。
首先，定义Sa、Sb、Sc、Sn分别为三相四桥臂三电平逆变器A、B、C、N 桥臂的输出状态：
则三相电压对应的电压矢量为：
式中，UAN表示A桥臂相对于N桥臂的电压矢量，UBN表示B桥臂相对于N桥臂的电压矢量，UCN表示C桥臂相对于N桥臂的电压矢量，Sa、Sb、Sc、Sn分别为三相四桥臂三电平逆变器A、B、C、N桥臂的输出状态，Udc表示直流侧电源电压。
步骤22：基于abc三维坐标系和电压矢量，构建空间多面体可控区域。
可选地，在一实施例中，空间多面体可控区域包括多个立方体子区域和多个四面体子区域。
可选地，如图3所示，图3是一实施例中步骤22的流程示意图，该步骤22可以包括：
步骤221：对电压矢量进行标准化处理。
具体地，采用以下公式对电压矢量进行标准化处理：
其中，表示标准化后A桥臂相对于N桥臂的电压矢量，表示标准化后B桥臂相对于N桥臂的电压矢量，表示标准化后C桥臂相对于N桥臂的电压矢量。
步骤222：将标准化处理后的电压矢量，引入abc三维坐标系中，构建空间多面体可控区域。
如图4所示，图4为本申请提供的空间多面体可控区域的示意图，在电压矢 量进行标准化处理之后，将标准化电压矢量引入abc三维坐标系中，构建获得一个十二面体的可控区域。
在一实施例中，该空间多面体可控区域包括三个大正方体和六个虚构立方体，该虚构立方体为调制比范围在0.866～1内的控制区域，并将可控区域平移至abc坐标系正方向，便于统一分析和计算。
步骤23：在空间多面体可控区域的多个子区域中，对预设的参考矢量进行定位，以生成参考矢量对应的参考电压矢量，参考电压矢量用于控制对应四桥臂的输出状态。
在一实施例中，预设的参考矢量进行定位，以生成参考矢量对应的参考电压矢量，可以先在多个立方体区域中进行定位，根据立方体区域的定位结果，再在多个四面体区域中进行定位，以得到最终的定位结果。如图5所示，图5是一实施例中步骤23的流程示意图，该步骤23可以包括：
步骤231：在空间多面体可控区域的多个子区域的立方体区域中，对预设的参考矢量进行定位。
其中，基于参考矢量取整后的参考原点坐标，在空间多面体可控区域中选取参考原点坐标所在的立方体；
其中，参考原坐标点为：
其中，表示参考矢量的a轴坐标，表示参考矢量的b轴坐标，表示参考矢量的c轴坐标。
具体可以参考图6，图6是本申请提供的立方体定位的流程示意图。
在一具体的实施例中，利用上述公式计算参考原坐标点(a，b，c)，然后利用图6的逻辑顺序进行判断：
a＜0.5，b＜0.5，c＜0.5，选择的立方体为cube1；
a＜0.5，b＜0.5，c≥0.5，选择的立方体为cube4；
a＜0.5，0.5≤b＜1.5，c＜0.5，选择的立方体为cube3；
a＜0.5，0.5≤b＜1.5，c≥0.5，选择的立方体为cube6；
a＜0.5，b≥1.5，选择的立方体为cube27；
0.5≤a＜1.5，b＜0.5，c＜0.5，选择的立方体为cube2；
0.5≤a＜1.5，b＜0.5，c≥0.5，选择的立方体为cube5；
0.5≤a＜1.5，0.5≤b＜1.5，c＜0.5，选择的立方体为cube7；
0.5≤a＜1.5，0.5≤b＜1.5，0.5≤c＜1.5，选择的立方体为cube8；
0.5≤a＜1.5，0.5≤b＜1.5，1.5≤c＜2.5，选择的立方体为cube11；
0.5≤a＜1.5，0.5≤b＜1.5，c≥2.5，选择的立方体为cube26；
0.5≤a＜1.5，1.5≤b＜2.5，c＜1.5，选择的立方体为cube10；
0.5≤a＜1.5，1.5≤b＜2.5，c≥1.5，选择的立方体为cube13；
0.5≤a＜1.5，b≥2.5，选择的立方体为cube28；
1.5≤a＜2.5，b＜0.5，选择的立方体为cube25；
1.5≤a＜2.5，0.5≤b＜1.5，c＜1.5，选择的立方体为cube9；
1.5≤a＜2.5，0.5≤b＜1.5，c≥1.5，选择的立方体为cube12；
1.5≤a＜2.5，1.5≤b＜2.5，c＜0.5，选择的立方体为cube23；
1.5≤a＜2.5，1.5≤b＜2.5，0.5≤c＜1.5，选择的立方体为cube14；
1.5≤a＜2.5，1.5≤b＜2.5，1.5≤c＜2.5，选择的立方体为cube15；
1.5≤a＜2.5，1.5≤b＜2.5，c≥2.5，选择的立方体为cube18；
1.5≤a＜2.5，b≥2.5，c＜2.5，选择的立方体为cube17；
1.5≤a＜2.5，b≥2.5，c≥2.5，选择的立方体为cube20；
a≥2.5，b＜1.5，选择的立方体为cube24；
a≥2.5，1.5≤b＜2.5，c＜1.5，选择的立方体为cube16；
a≥2.5，1.5≤b＜2.5，c≥1.5，选择的立方体为cube19；
a≥2.5，b≥2.5，c＜2.5，选择的立方体为cube21；
a≥2.5，b≥2.5，c≥2.5，选择的立方体为cube22。
步骤232：基于立方体区域的定位结果，在空间多面体可控区域的多个子区域的四面体区域中，对预设的参考矢量进行定位。
对定位的目标立方体以参考矢量对应的原坐标为参考点，采用三个45°切面进行划分，以参考原点坐标为中心计算三个切面的距离，确定参考矢量所在的四面体位置，三个45°切面包括以过原点的a-b轴45°切面、c-b轴45°切面以及a-c轴45°切面。
具体可以参考图7，图7是本申请提供的四面体定位的流程示意图。
在一具体的实施例中，利用上述公式计算参考原坐标点(a，b，c)以及参考矢量(uan，ub n，uc n)，然后利用图7的逻辑顺序进行判断：
ucn-c≥ubn-b，uan-a≥ucn-c，选择的1号四面体；
ucn-c≥ubn-b，uan-a＜ucn-c，uan-a≥ubn-b，选择的2号四面体；
ucn-c≥ubn-b，uan-a＜ucn-c，uan-a＜ubn-b，选择的3号四面体；
ucn-c＜ubn-b，ucn-c≥uan-a，选择的4号四面体；
ucn-c＜ubn-b，ucn-c＜uan-a，ubn-b≥uan-a，选择的5号四面体；
ucn-c＜ubn-b，ucn-c＜uan-a，ubn-b＜uan-a，选择的6号四面体。
步骤233：根据最终的定位结果，生成参考矢量对应的参考电压矢量。
步骤24：在减少零电平输出状态的调制策略下，对参考电压矢量进行排序。
其中，步骤24可以具体为：确定空间多面体可控区域中参考电压矢量的合成顺序；以减小各桥臂流入中点电流为目标，调整参考电压矢量的顺序。
由于所有电压矢量中，能对中点电压产生影响的只有零电平状态，即O状态，要尽可能的使O状态产生的影响减小的话，可以利用参考电压矢量的新排列方法来进行抵消。新矢量排列方式为(记某一个四面体的四个参考电压矢量为V1-V4)：
1-11号立方体中的四面体的参考电压矢量顺序：V4、V3、V2、V1；
12-22号立方体的参考电压矢量顺序：V1、V2、V3、V4；
23、25、27号虚构立方体中的四面体的参考电压矢量顺序：V2、V3、V4、V1；
24、26、28号虚构立方体中的四面体的参考电压矢量顺序：V3、V2、V1、V4。
步骤25：根据排序后的参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列，以对三相四桥臂三电平逆变器的中点电压进行调节。
如图8所示，图8是一实施例中步骤25的流程示意图，该步骤25可以包括：
步骤251：确定参考电压矢量对应的作用时间。
采用以下公式确定参考电压矢量对应的占空比：
将占空比乘以开关周期Ts，得到参考电压矢量对应的作用时间；
其中，为参考电压矢量所在的四面体定点坐标，d1-4为参考电压矢量的占空比。
其中，电压矢量为V1-V4相对应作用时间则为T1-T4，作用时间顺序与上述参考电压矢量的顺序保持一致。
步骤252：根据排序后的参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列。
根据排序后的参考电压矢量的排列方式，对参考电压矢量的作用时间进行排序；将排序后的作用时间进行九段式分配；九段式分配为：九段矢量中的第一段、第五段和第九段分配同一段时间，第一段和第九段分别占1/4，第五段占1/2，剩余六段根据对称性各占对应时间段的1/2(即Tx1/4、Tx2/2、Tx3/2、Tx4/2、Tx1/2、Tx4/2、Tx3/2、Tx2/2、Tx1/4)；根据电压矢量来确定四桥臂的状态，为每个状态分配对应的四个开关状态，形成脉冲序列。具体可以参阅图9，图9是本申请提供的九段式时间分配方法示意图。
电压矢量到开关信号的转换：在生成驱动脉冲之前先根据电压矢量来确定4个桥臂的状态，然后为每个状态分配对应的4个开关状态，这也4*4正好可以得到16路的开关脉冲序列。
可以理解地，采用九段式的时间分配方式，可以使参考电压矢量中的多个矢量具有相同的作用时间，从而实现了控制三电平逆变器和实现中点电位平衡的双重目的。
区别于现有技术，本实施例提供的三相四桥臂三电平逆变器的电压调节方法包括：确定三相电压对应的电压矢量；基于abc三维坐标系和电压矢量，构建空间多面体可控区域，空间多面体可控区域包括多个四面体子区域和立方体子区域；在空间多面体可控区域的多个子区域中，对预设的参考矢量进行定位，以生成参考矢量对应的参考电压矢量，参考电压矢量用于控制对应四桥臂的输出状态；在减少零电平输出状态的调制策略下，对参考电压矢量进行排序；根据排序后的参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列，以对三相四桥臂三电平逆变器的中点电压进行调节。通过上述方式，本实施例具有以下有益效果：
(1)在不增设控制器的条件下，实现了三相四桥臂三电平逆变器中点电压的平衡调节。
(2)引入了六个虚构立方体，保证在参考矢量的位置判断时，减少了传统SVPWM调制方法的多余可控区域，简化了传统SVPWM调制方法的复杂度。
(3)采用调制策略：以减少各个桥臂流入中点电流为目标，对原参考电压矢量进行顺序的改动，从而将影响中点电压平衡的零电平输出状态进行抵消。
为了验证所提三相四桥臂三电平逆变器中点电压平衡方法的有效性，搭建了三相四桥臂三电平逆变器空间矢量调制的仿真实验，逆变器参数如下表所示：
下面参阅图10和图11，图10是本申请提供的平衡负载工况下中点点位图，图11是本申请通过电压调节方法平衡之后的实际负载工况下的中点点位图。图中横轴为时间，竖轴为电压，其中图10中的逆变器功率为5KW，图11中的逆变 器功率为100KW；由图可知，通过本实施例提供的方法可以很好的保持中点电压平衡，且延长时间轴后可以看出运行非常稳定。
以上对本申请实施例所提供的显示屏进行了详细介绍，本文中应用了具体个例对本申请的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本申请的方法及其核心思想；同时，对于本领域的技术人员，依据本申请的思想，在具体实施方式及应用范围上均会有改变之处，综上所述，本说明书内容不应理解为对本申请的限制。

Claims (12)

  1. 一种三相四桥臂三电平逆变器的电压调节方法，其特征在于，所述方法包括：
    确定三相电压对应的电压矢量；
    基于abc三维坐标系和所述电压矢量，构建空间多面体可控区域；
    在所述空间多面体可控区域的多个子区域中，对预设的参考矢量进行定位，以生成所述参考矢量对应的参考电压矢量，所述参考电压矢量用于控制对应四桥臂的输出状态；
    在减少零电平输出状态的调制策略下，对所述参考电压矢量进行排序；
    根据排序后的所述参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列，以对所述三相四桥臂三电平逆变器的中点电压进行调节。
  2. 根据权利要求1所述的方法，其特征在于，
    所述确定三相电压对应的电压矢量，包括：
    根据桥臂的输出状态，确定三相电压对应的电压矢量，所述输出状态包括高电平、零电平和低电平。
  3. 根据权利要求2所述的方法，其特征在于，
    所述根据桥臂的输出状态，确定三相电压对应的电压矢量，包括：
    采用以下公式确定三相电压对应的电压矢量：
    其中，UAN表示A桥臂相对于N桥臂的电压矢量，UBN表示B桥臂相对于N桥臂的电压矢量，UCN表示C桥臂相对于N桥臂的电压矢量， Sa、Sb、Sc、Sn分别为三相四桥臂三电平逆变器A、B、C、N桥臂的输出状态，Udc表示直流侧电源电压。
  4. 根据权利要求1所述的方法，其特征在于，
    所述基于abc三维坐标系和所述电压矢量，构建空间多面体可控区域，包括：
    对所述电压矢量进行标准化处理；
    将标准化处理后的所述电压矢量，引入abc三维坐标系中，构建空间多面体可控区域。
  5. 根据权利要求4所述的方法，其特征在于，
    所述对所述电压矢量进行标准化处理，包括：
    采用以下公式对所述电压矢量进行标准化处理：
    其中，表示标准化后A桥臂相对于N桥臂的电压矢量，表示标准化后B桥臂相对于N桥臂的电压矢量，表示标准化后C桥臂相对于N桥臂的电压矢量。
  6. 根据权利要求1所述的方法，其特征在于，
    所述空间多面体可控区域为十二面体可控区域，所述十二面体可控区域包括由标准化电压矢量构建的三个正方体区域、以及贴合在所述三个正方体区域外侧的六个虚构立方体区域。
  7. 根据权利要求1所述的方法，其特征在于，
    所述在所述空间多面体可控区域的多个子区域中，对预设的参考矢量进行定位，以生成所述参考矢量对应的参考电压矢量，包括：
    在所述空间多面体可控区域的多个子区域的立方体区域中，对预设的参考矢量进行定位；
    基于所述立方体区域的定位结果，在所述空间多面体可控区域的多个子区域的四面体区域中，对预设的参考矢量进行定位；
    根据最终的定位结果，生成所述参考矢量对应的参考电压矢量。
  8. 根据权利要求7所述的方法，其特征在于，
    所述在所述空间多面体可控区域的多个子区域的立方体区域中，对预设的参考矢量进行定位，包括：
    基于参考矢量取整后的参考原点坐标，在空间多面体可控区域中选取参考原点坐标所在的立方体；
    其中，所述参考原坐标点为：
    其中，表示参考矢量的a轴坐标，表示参考矢量的b轴坐标，表示参考矢量的c轴坐标。
  9. 根据权利要求7或8所述的方法，其特征在于，
    所述在所述空间多面体可控区域的多个子区域的四面体区域中，对预设的参考矢量进行定位，包括：
    对定位的目标立方体以参考矢量对应的原坐标为参考点，采用三个45°切面进行划分，以参考原点坐标为中心计算三个切面的距离，确定参考矢量所在的四面体位置，所述三个45°切面包括以过原点的a-b轴45°切面、c-b轴45°切面以及a-c轴45°切面。
  10. 根据权利要求1所述的方法，其特征在于，
    所述在减少零电平输出状态的调制策略下，对所述参考电压矢量进行排序，包括：
    确定空间多面体可控区域中参考电压矢量的合成顺序；
    以减小各桥臂流入中点电流为目标，调整所述参考电压矢量的顺序。
  11. 根据权利要求1所述的方法，其特征在于，
    所述根据排序后的所述参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列，包括：
    采用以下公式确定参考电压矢量对应的占空比：
    将占空比乘以开关周期，得到所述参考电压矢量对应的作用时间；
    其中，为参考电压矢量所在的四面体定点坐标，d1-4为所述参考电压矢量的占空比；
    根据排序后的所述参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列。
  12. 根据权利要求11所述的方法，其特征在于，
    所述根据排序后的所述参考电压矢量及对应的作用时间，生成桥臂的开关脉冲序列，包括：
    根据排序后的参考电压矢量的排列方式，对参考电压矢量的作用时间进行排序；
    将排序后的作用时间进行九段式分配；所述九段式分配为：九段矢量中的第一段、第五段和第九段分配同一段时间，第一段和第九段分别占1/4，第五段占1/2，剩余六段根据对称性各占对应时间段的1/2；
    根据电压矢量来确定四桥臂的状态，为每个状态分配对应的四个开关状态，形成脉冲序列。
PCT/CN2023/122773 2022-09-30 2023-09-28 一种三相四桥臂三电平逆变器的电压调节方法 WO2024067836A1 (zh)

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