WO2018171769A1 - Z-source network active neutral point clamped five-level photovoltaic grid-connected inverter system - Google Patents

Z-source network active neutral point clamped five-level photovoltaic grid-connected inverter system Download PDF

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WO2018171769A1
WO2018171769A1 PCT/CN2018/080352 CN2018080352W WO2018171769A1 WO 2018171769 A1 WO2018171769 A1 WO 2018171769A1 CN 2018080352 W CN2018080352 W CN 2018080352W WO 2018171769 A1 WO2018171769 A1 WO 2018171769A1
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electronic switch
power electronic
switch tube
power
inductor
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PCT/CN2018/080352
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French (fr)
Chinese (zh)
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黄敏
杨勇
方刚
卢进军
谢胜仁
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江苏固德威电源科技股份有限公司
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Publication of WO2018171769A1 publication Critical patent/WO2018171769A1/en

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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
    • H02M7/487—Neutral point clamped inverters
    • H02J3/385—
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

  • the invention relates to a Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system.
  • the inverter As a renewable energy source, the inverter is connected to the grid or load. It is the core device of the entire renewable energy power generation system, and its performance affects the entire renewable energy power generation system.
  • multi-level inverters Compared with ordinary two-level inverters, multi-level inverters have low voltage stress, low voltage change rate (du/dt), low inverter output harmonics, high inverter efficiency and inverse The advantages of changing the common mode voltage are small. Therefore, multi-level inverters have been widely used in renewable energy generation.
  • the upper and lower power electronic switch tubes of the inverter bridge arm cannot be turned on at the same time (straight-through), otherwise a short circuit will occur and the inverter will be damaged. Therefore, in order to prevent the inverter power electronic switch tube from passing through, the dead time is added between the upper and lower power electronic switch signals of the inverter bridge arm, but the addition of dead time affects the output waveform quality of the inverter.
  • photovoltaic grid-connected inverters For photovoltaic grid-connected inverters, they can generally be divided into DC/DC conversion and DC/AC conversion.
  • the DC/DC conversion realizes the maximum power tracking of the photovoltaic array, and the DC/AC conversion realizes the active power and reactive power control of the photovoltaic grid-connected inverter.
  • the DC/DC converter commonly used in photovoltaic grid-connected inverters is a BOOST boost converter.
  • Z source network inverter has the following advantages compared with the traditional inverter: (1) realize the increase and decrease of the DC side input voltage; (2) DC/DC converter does not need the power electronic switch tube to improve the inverse The efficiency of the transformer; (3) allows the bridge arm to pass through, the inverter does not need dead zone compensation, and the system reliability is greatly improved.
  • the general DC/DC converter uses BOOST boost circuit to achieve the most power tracking.
  • the DC/AC converter uses a two-level voltage inverter.
  • the DC/AC converter In order to meet the grid-connected inverter output current grid-connected standard (the rated load grid-connected inverter output current total harmonic is less than 4%), the DC/AC converter has a larger filter inductor (generally greater than 2mH), and The switching frequency of the network inverter is relatively high (generally greater than 15k). It can be seen that the photovoltaic grid-connected system in the prior art does not appear as a product combining the advantages of the Z-source network inverter and the multi-level inverter system.
  • a Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system comprises a DC connected to a photovoltaic panel a bus source connected Z source network, an active midpoint clamped five-level inverter connected to the Z source network, and an output of the active midpoint clamped five-level inverter is filtered And connected to the grid.
  • the Z source network includes two equivalent inductors and two equivalent capacitors, and the two inductors are respectively a first inductor and a second inductor; the two ends of the inductor are respectively a terminal And the b terminal, the a terminal of the first inductor is connected to the positive pole of the DC bus, and the b terminal of the first inductor is connected to the active midpoint clamped five-level inverter, The a terminal of the second inductor is connected to the negative pole of the DC bus, and the b terminal of the second inductor is connected to the active midpoint clamped five-level inverter; Connected between the a terminal of the first inductor and the b terminal of the second inductor, and the other ends of the other capacitor are respectively connected to the b terminal of the first inductor and the a terminal of the second inductor between.
  • the active midpoint clamped five-level inverter comprises a first power electronic switch tube, a second power electronic switch tube, a third power electronic switch tube, a fourth power electronic switch tube, and a fifth power electronic a switch tube, a sixth power electronic switch tube, a first power diode, a second power diode, and a clamp capacitor;
  • the first power electronic switch tube, the second power electronic switch tube, the third power electronic switch tube, and the fourth power electronic switch tube are sequentially connected in series and connected to the b end of the first inductor Between the b-ends of the second inductor, the first power diode and the fifth power electronic switch are connected in series to form a first bridge arm, and the second power diode is connected in series with the sixth power electronic switch Forming a second bridge arm, the first bridge arm being connected between a neutral point of the DC bus and a common end of the first power electronic switch tube and the second power electronic switch tube, the second a bridge arm is connected between a neutral point of the DC bus and a common end of the third power electronic switch tube and the fourth power electronic switch tube, and the clamp capacitor is connected to the first power electronic switch The common end of the tube and the second power electronic switch tube is between the common end of the third power electronic switch tube and the fourth power electronic switch tube.
  • the first power electronic switch tube includes a switch tube S11 and a switch tube S12 that use the same drive signal and are connected in series;
  • the fourth power electronic switch tube includes a switch tube S41 and a switch tube S42 that use the same drive signal and are connected in series. .
  • the first power electronic switch tube, the second power electronic switch tube, the third power electronic switch tube, and the fourth power electronic switch tube all have anti-parallel diodes.
  • a drain of the first power electronic switch is connected to a b end of the first inductor, and a source of the first power electronic switch is opposite to a drain of the second power electronic switch Connecting, a source of the second power electronic switch tube is connected to a drain of the third power electronic switch tube, and a source of the third power electronic switch tube and a drain of the fourth power electronic switch tube a pole connection, a source of the fourth power electronic switch tube is connected to a b end of the second inductor;
  • a cathode of the first power diode is connected to a neutral point of the DC bus, a cathode of the first power diode is connected to a source of the fifth power electronic switch, and the fifth power electronic switch a drain of the tube is connected to a common end of the first power electronic switch tube and the second power electronic switch tube;
  • a cathode of the second power diode is connected to a neutral point of the DC bus, a cathode of the second power diode is connected to a source of the sixth power electronic switch, and the sixth power electronic switch A drain of the tube is connected to a common end of the third power electronic switch tube and the fourth power electronic switch tube.
  • a common end of the second power electronic switch tube and the third power electronic switch tube forms an output end of the active midpoint clamped five-level inverter and is connected to the filter inductor.
  • the first power electronic switch tube, the second power electronic switch tube, the third power electronic switch tube, the fourth power electronic switch tube, the fifth power electronic switch tube, the The sixth power electronic switch tube uses an insulated gate bipolar transistor.
  • the anode of the DC bus is connected to the Z source network through a first reverse blocking diode, and the cathode of the DC bus is connected to the Z source network through a second reverse blocking diode.
  • the present invention has the following advantages over the prior art: the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system of the present invention combines the advantages of the Z-source network and multi-level The performance of the photovoltaic grid-connected inverter is greatly improved, the filter inductance of the photovoltaic grid-connected inverter system and the switching frequency of the inverter system can be reduced, and the reliability of the photovoltaic grid-connected inverter system is improved.
  • FIG. 1 is a schematic view of a photovoltaic power generation inverter system of the present invention.
  • FIG. 2 is a schematic view of State 1 of the photovoltaic power generation inverter system of the present invention.
  • FIG. 3 is a schematic view of State 2 of the photovoltaic power generation inverter system of the present invention.
  • FIG. 4 is a schematic view of state 3 of the photovoltaic power generation inverter system of the present invention.
  • Figure 5 is a schematic illustration of State 4 of a photovoltaic power generation inverter system of the present invention.
  • Figure 6 is a schematic illustration of state 5 of a photovoltaic power generation inverter system of the present invention.
  • Figure 7 is a schematic illustration of state 6 of a photovoltaic power generation inverter system of the present invention.
  • Figure 8 is a schematic illustration of state 7 of a photovoltaic power generation inverter system of the present invention.
  • Figure 9 is a schematic illustration of state 8 of a photovoltaic power generation inverter system of the present invention.
  • Figure 10 is a schematic illustration of State 9 of a photovoltaic power generation inverter system of the present invention.
  • a photovoltaic power generation inverter system includes a photovoltaic panel, a DC bus PN connected to the photovoltaic panel, and a Z source network connected between the DC bus PN and the power grid.
  • P is the DC bus positive pole
  • N is the DC bus negative pole
  • two voltage dividing filter capacitors C 1 and C 2 are connected in series on the DC bus
  • the midpoint of the voltage dividing filter capacitor C 1 and the voltage dividing filter capacitor C 2 is DC.
  • Neutral point O of bus PN is the midpoint of the voltage dividing filter capacitor C 1 and the voltage dividing filter capacitor C 2 is DC.
  • the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system includes a Z-source network 1 and an active midpoint clamped five-level inverter 2.
  • the Z source network 1 is connected to the DC bus PN connected to the photovoltaic panel
  • the active midpoint clamped five-level inverter 2 is connected to the Z source network 1
  • the active midpoint clamped five-level inverter an output terminal 2 via the filter inductor L 3 and is connected to the grid e g.
  • the Z source network 1 includes two equivalent inductors L 1 , L 2 and two equivalent capacitors C 3 , C 4 , and the two inductors L 1 and L 2 are the first inductor L 1 and the second inductor L, respectively. 2 .
  • the inductors L 1 and L 2 each have two ends, which are respectively referred to as an a terminal and a b terminal.
  • the a terminal of the first inductor L 1 is connected to the positive pole P of the DC bus PN, the b terminal of the first inductor L 1 is connected to the active midpoint clamped five-level inverter 2, and the second inductor L 2 is a The terminal is connected to the negative pole N of the DC bus PN, and the b terminal of the second inductor L 2 is connected to the active midpoint clamped five-level inverter 2.
  • Two ends of one capacitor C 3 are respectively connected between the a terminal of the first inductor L 1 and the b terminal of the second inductor L 2 , and the two ends of the other capacitor C 4 are respectively connected to the b terminal of the first inductor L 1 and Between the a ends of the second inductance L 2 , thereby forming the Z source network 1 in an X-like form.
  • the anode P of the DC bus PN is connected to the Z source network 1 through the first reverse blocking diode D1, and the cathode N of the DC bus PN is connected to the Z source network 1 through the second reverse blocking diode D2, that is, DC PN positive bus P and the first reverse blocking diode D1 is connected to the positive electrode, the first reverse blocking diode D1 and the negative electrode 1 in the source network Z L a 1 of a first end of the inductor is connected to the DC bus PN
  • the anode N is connected to the cathode of the second reverse blocking diode D2, and the anode of the second reverse blocking diode D2 is connected to the a terminal of the second inductor L 2 in the Z source network 1.
  • the first reverse blocking diode D1 and the second reverse blocking diode D2 function as a reverse blocking in the through state.
  • the b-end of the first inductor L 1 constitutes a node P1
  • the b-end of the second inductor L 2 constitutes a node N1.
  • the active midpoint clamped five-level inverter 2 includes a first power electronic switch tube S1, a second power electronic switch tube S2, a third power electronic switch tube S3, a fourth power electronic switch tube S4, and a fifth power electronics.
  • the first power electronic switch tube S1, the second power electronic switch tube S2, the third power electronic switch tube S3, the fourth power electronic switch tube S4, the fifth power electronic switch tube S5, and the sixth power electronic switch tube S6 are both Insulated Gate Bipolar Transistor (IGBT) is used.
  • IGBT Insulated Gate Bipolar Transistor
  • the common end of the first power electronic switch tube and the second power electronic switch tube constitute a node P2
  • the common end of the third power electronic switch tube and the fourth power electronic switch tube constitute a node N2.
  • the first power diode D3 is connected in series with the fifth power electronic switch S5 to form a first bridge arm, and the second power diode D4 is connected in series with the sixth power electronic switch S6 to form a second bridge arm, and the first bridge arm is connected to the DC bus.
  • the second bridge arm is connected to the neutral point O of the DC bus PN and the third power electronic switch between the common terminal N2 of S3 and S4 is a fourth of the power electronic switches, clamp capacitor C 5 is connected to a common terminal P2 of the first power electronic switches S1 and S2 is a second power electronic switches of the third power electronic switch S3 Between the common terminal N2 of the fourth power electronic switch S4.
  • the power drain of the first electronic switch S1 and a first end of the inductor L b is 1, i.e. the node P1 is connected to the drain electrode of the first power source of the electronic switch S1 and a second power electronics the switch S2 Connected, the source of the second power electronic switch S2 is connected to the drain of the third power electronic switch S3, and the source of the third power electronic switch S3 is connected to the drain of the fourth power electronic switch S4.
  • the source of the fourth power electronic switch S4 is connected to the b-end of the second inductor L 2 , that is, the node N1.
  • the cathode of the first power diode D3 is connected to the neutral point O of the DC bus PN, the anode of the first power diode D3 is connected to the source of the fifth power electronic switch S5, and the drain of the fifth power electronic switch S5 is connected.
  • the node common to the first power electronic switch S1 and the second power electronic switch S2, that is, the node P2 is connected.
  • the cathode of the second power diode D4 is connected to the neutral point O of the DC bus PN, the anode of the second power diode D4 is connected to the source of the sixth power electronic switch S6, and the drain of the sixth power electronic switch S6 is connected.
  • the common terminal of the third power electronic switch S3 and the fourth power electronic switch S4, that is, the node N2 is connected.
  • the common terminal of the second power electronic switch S2 and the third power electronic switch S3, that is, the source of the second power electronic switch S2 forms the output A of the active midpoint clamped five-level inverter 2
  • the filter inductor phase L 3 is connected and then connected to the grid e g .
  • the reverse voltage of the first power electronic switch S1 and the fourth power electronic switch S4 is 3/4 of the DC bus PN voltage. Therefore, in order to reduce the first power electronic switch S1 and the fourth power electronic switch S4
  • the reverse voltage the first power electronic switch S1 includes a switch S11 and a switch S12 connected in series
  • the fourth power electronic switch includes a switch S41 and a switch S42 connected in series.
  • the switch S11 and the switch S12 use the same drive signal.
  • the switch S41 and the switch S42 use the same drive signal.
  • the switch S11, the switch S12, the switch S41, and the switch S42 are also insulated gate bipolar transistors.
  • the drain of the switch S11 constitutes the drain of the first power electronic switch S1
  • the source of the switch S11 is connected to the drain of the switch S12
  • the source of the switch S12 constitutes the source of the first power electronic switch S1.
  • the drain of the switch S41 constitutes the drain of the fourth power electronic switch S4
  • the source of the switch S41 is connected to the drain of the switch S42
  • the source of the switch S42 constitutes the source of the fourth power electronic switch S4. pole.
  • the first power electronic switch tube S1, the second power electronic switch tube S2, the third power electronic switch tube S3, and the fourth power electronic switch tube S4 each have an anti-parallel diode, and the fifth power electronic switch tube S5 and the sixth power The electronic switch S6 has no anti-parallel diodes.
  • the above-mentioned Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system uses the capacitor neutral point O of the DC bus PN as a reference voltage point (the voltage of the DC bus PN is V dc ), and the active clamp
  • the bit capacitor C 5 voltage is controlled to V dc /4, the inverter output voltage and the power electronic switch signal of the inverter (where “1” represents the power electronic switch is turned on, "0” represents the power electronic switch is turned off) and
  • the relationship between the DC bus voltage V dc is shown in Table 1.
  • the "state 9" is the Z source network 1 through state.
  • the above scheme is a Z-source network 1 active midpoint clamped five-level photovoltaic grid-connected inverter system, which realizes a DC/DC converter function, and the output level is 5, which improves the photovoltaic grid-connected inverter. Performance (current ripple, efficiency, voltage change rate, etc.); at the same time, the inverter switch tube can be directly connected, which improves the reliability of the inverter and has a good application prospect.

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  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

A Z-source network active neutral point clamped five-level photovoltaic grid-connected inverter system, comprising a Z-source network (1) which is connected with a direct current bus connected with a photovoltaic cell panel, and an active neutral point clamped five-level inverter (2) which is connected with the Z-source network. An output end of the active neutral point clamped five-level inverter is connected with a power grid by means of a filter inductor (L3). The inverter system can reduce the filter inductance magnitude of the photovoltaic grid-connected inverter system and the switching frequency of the inverter system, and can improve the reliability of the photovoltaic grid-connected inverter system.

Description

Z源网络有源中点钳位五电平光伏并网逆变系统Z source network active midpoint clamp five-level photovoltaic grid-connected inverter system 技术领域Technical field
本发明涉及一种Z源网络有源中点钳位五电平光伏并网逆变系统。The invention relates to a Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system.
背景技术Background technique
随着能源危机和环境问题日益严重，可再生能源发电技术受到了越来越多的关注和研究。逆变器作为可再生能源发电与电网或负载接口，是整个可再生能源发电系统核心装置，其性能影响整个可再生能源发电系统。With the energy crisis and environmental problems becoming more and more serious, renewable energy power generation technology has received more and more attention and research. As a renewable energy source, the inverter is connected to the grid or load. It is the core device of the entire renewable energy power generation system, and its performance affects the entire renewable energy power generation system.
多电平逆变器与普通两电平逆变器相比，具有电力电子器件电压应力低、电压变化率(du/dt)低、逆变器输出谐波小、逆变器效率高以及逆变共模电压小等优点。因此，多电平逆变器在可再生能源发电中得到了广泛的应用。对于电压型光伏并网逆变器，逆变器桥臂上、下电力电子开关管不能同时导通(直通)，否则会发生短路，损坏逆变器。因此，为了防止逆变器电力电子开关管直通，逆变器桥臂上、下电力电子开关管信号之间加入死区时间，但死区时间的加入会影响逆变器输出波形质量。Compared with ordinary two-level inverters, multi-level inverters have low voltage stress, low voltage change rate (du/dt), low inverter output harmonics, high inverter efficiency and inverse The advantages of changing the common mode voltage are small. Therefore, multi-level inverters have been widely used in renewable energy generation. For voltage-type photovoltaic grid-connected inverters, the upper and lower power electronic switch tubes of the inverter bridge arm cannot be turned on at the same time (straight-through), otherwise a short circuit will occur and the inverter will be damaged. Therefore, in order to prevent the inverter power electronic switch tube from passing through, the dead time is added between the upper and lower power electronic switch signals of the inverter bridge arm, but the addition of dead time affects the output waveform quality of the inverter.
对于光伏并网逆变器，一般可分为直流/直流变换、直流/交流变换。直流/直流变换实现光伏阵列的最大功率跟踪，而直流/交流变换实现光伏并网逆变器有功功率、无功功率控制等。光伏并网逆变器中常用的直流/直流变换器为BOOST升压变换器。For photovoltaic grid-connected inverters, they can generally be divided into DC/DC conversion and DC/AC conversion. The DC/DC conversion realizes the maximum power tracking of the photovoltaic array, and the DC/AC conversion realizes the active power and reactive power control of the photovoltaic grid-connected inverter. The DC/DC converter commonly used in photovoltaic grid-connected inverters is a BOOST boost converter.
Z源网络逆变器，和传统的逆变器相比，具有以下优点：(1)实现直流侧输入电压的升高和降低；(2)直流/直流变换器无需电力电子开关管，提高逆变器效率；(3)允许桥臂直通，逆变器无需要死区补偿，系统可靠性大大提高。Z source network inverter has the following advantages compared with the traditional inverter: (1) realize the increase and decrease of the DC side input voltage; (2) DC/DC converter does not need the power electronic switch tube to improve the inverse The efficiency of the transformer; (3) allows the bridge arm to pass through, the inverter does not need dead zone compensation, and the system reliability is greatly improved.
目前，对于商用单相光伏并网逆变器，一般直流/直流变换器采用BOOST升压电路来实现最在功率跟踪。而直流/交流变换器采用两电平电压型逆变器。为了满足并网逆变器输出电流并网标准(额定负载并网逆变器输出电流总谐波小于4％)，直流/交流变换器的滤波电感选比较大(一般大于2mH)，同时，并网逆变器的开关频率选择比较高(一般大于15k)。可见，现有技术中的光伏并网系统，并未出现一种结合了Z源网络逆变器、多电平逆变系统的优点的产品出现。At present, for commercial single-phase photovoltaic grid-connected inverters, the general DC/DC converter uses BOOST boost circuit to achieve the most power tracking. The DC/AC converter uses a two-level voltage inverter. In order to meet the grid-connected inverter output current grid-connected standard (the rated load grid-connected inverter output current total harmonic is less than 4%), the DC/AC converter has a larger filter inductor (generally greater than 2mH), and The switching frequency of the network inverter is relatively high (generally greater than 15k). It can be seen that the photovoltaic grid-connected system in the prior art does not appear as a product combining the advantages of the Z-source network inverter and the multi-level inverter system.
发明内容Summary of the invention
本发明的目的是提供一种结合多种逆变系统的优点，从而具有较佳性能的Z源网络有源中点钳位五电平光伏并网逆变系统。It is an object of the present invention to provide a Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system that combines the advantages of multiple inverter systems to provide better performance.
为达到上述目的，本发明采用的技术方案是：In order to achieve the above object, the technical solution adopted by the present invention is:
一种Z源网络有源中点钳位五电平光伏并网逆变系统，所述Z源网络有源中点钳位五电平光伏并网逆变系统包括与光伏电池板所连接的直流母线相连接的Z源网络、与所述Z源网络相连接的有源中点钳位五电平逆变器，所述有源中点钳位五电平逆变器的输出端经滤波电感而与电网相连接。A Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system, the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system comprises a DC connected to a photovoltaic panel a bus source connected Z source network, an active midpoint clamped five-level inverter connected to the Z source network, and an output of the active midpoint clamped five-level inverter is filtered And connected to the grid.
优选的，所述Z源网络包括两个等值的电感和两个等值的电容，两个所述的电感分别为第一电感和第二电感；所述电感的两端分别为其a端和b端，所述第一电感的a端与所述直流母线的正极相连接，所述第一电感的b端与所述有源中点钳位五电平逆变器相连接，所述第二电感的a端与所述直流母线的负极相连接，所述第二电感的b端与所述有源中点钳位五电平逆变器相连接；一个所述电容的两端分别连接在所述第一电感的a端和所述第二电感的b端之间，另一个所述电容的两端分别连接在所述第一电感的b端和所述第二电感的a端之间。Preferably, the Z source network includes two equivalent inductors and two equivalent capacitors, and the two inductors are respectively a first inductor and a second inductor; the two ends of the inductor are respectively a terminal And the b terminal, the a terminal of the first inductor is connected to the positive pole of the DC bus, and the b terminal of the first inductor is connected to the active midpoint clamped five-level inverter, The a terminal of the second inductor is connected to the negative pole of the DC bus, and the b terminal of the second inductor is connected to the active midpoint clamped five-level inverter; Connected between the a terminal of the first inductor and the b terminal of the second inductor, and the other ends of the other capacitor are respectively connected to the b terminal of the first inductor and the a terminal of the second inductor between.
优选的，所述有源中点钳位五电平逆变器包括第一电力电子开关管、第二电力电子开关管、第三电力电子开关管、第四电力电子开关管、第五电力电子开关管、第六电力电子开关管、第一电力二极管、第二电力二极管、钳位电容；Preferably, the active midpoint clamped five-level inverter comprises a first power electronic switch tube, a second power electronic switch tube, a third power electronic switch tube, a fourth power electronic switch tube, and a fifth power electronic a switch tube, a sixth power electronic switch tube, a first power diode, a second power diode, and a clamp capacitor;
所述第一电力电子开关管、所述第二电力电子开关管、所述第三电力电子开关管、所述第四电力电子开关管依次串联并连接在所述第一电感的b端和所述第二电感的b端之间，所述第一电力二极管与所述第五电力电子开关管相串联构成第一桥臂，所述第二电力二极管与所述第六电力电子开关管相串联构成第二桥臂，所述第一桥臂连接于所述直流母线的中性点与所述第一电力电子开关管和所述第二电力电子开关管的共同端之间，所述第二桥臂连接于所述直流母线的中性点与所述第三电力电子开关管和所述第四电力电子开关管的共同端之间，所述钳位电容连接于所述第一电力电子开关管和所述第二电力电子开关管的共同端与所述第三电力电子开关管和所述第四电力电子开关管的共同端之间。The first power electronic switch tube, the second power electronic switch tube, the third power electronic switch tube, and the fourth power electronic switch tube are sequentially connected in series and connected to the b end of the first inductor Between the b-ends of the second inductor, the first power diode and the fifth power electronic switch are connected in series to form a first bridge arm, and the second power diode is connected in series with the sixth power electronic switch Forming a second bridge arm, the first bridge arm being connected between a neutral point of the DC bus and a common end of the first power electronic switch tube and the second power electronic switch tube, the second a bridge arm is connected between a neutral point of the DC bus and a common end of the third power electronic switch tube and the fourth power electronic switch tube, and the clamp capacitor is connected to the first power electronic switch The common end of the tube and the second power electronic switch tube is between the common end of the third power electronic switch tube and the fourth power electronic switch tube.
优选的，所述第一电力电子开关管包括采用相同驱动信号且串联的开关管S11、开关管S12；所述第四电力电子开关管包括采用相同驱动信号且串联 的开关管S41、开关管S42。Preferably, the first power electronic switch tube includes a switch tube S11 and a switch tube S12 that use the same drive signal and are connected in series; the fourth power electronic switch tube includes a switch tube S41 and a switch tube S42 that use the same drive signal and are connected in series. .
优选的，所述第一电力电子开关管、所述第二电力电子开关管、所述第三电力电子开关管、得到第四电力电子开关管均具有反并联二极管。Preferably, the first power electronic switch tube, the second power electronic switch tube, the third power electronic switch tube, and the fourth power electronic switch tube all have anti-parallel diodes.
优选的，所述第一电力电子开关管的漏极与所述第一电感的b端相连接，所述第一电力电子开关管的源极与所述第二电力电子开关管的漏极相连接，所述第二电力电子开关管的源极与所述第三电力电子开关管的漏极相连接，所述第三电力电子开关管的源极与所述第四电力电子开关管的漏极相连接，所述第四电力电子开关管的源极与所述第二电感的b端相连接；Preferably, a drain of the first power electronic switch is connected to a b end of the first inductor, and a source of the first power electronic switch is opposite to a drain of the second power electronic switch Connecting, a source of the second power electronic switch tube is connected to a drain of the third power electronic switch tube, and a source of the third power electronic switch tube and a drain of the fourth power electronic switch tube a pole connection, a source of the fourth power electronic switch tube is connected to a b end of the second inductor;
所述第一电力二极管的负极与所述直流母线的中性点相连接，所述第一电力二极管的正极与所述第五电力电子开关管的源极相连接，所述第五电力电子开关管的漏极与所述第一电力电子开关管和所述第二电力电子开关管的共同端相连接；a cathode of the first power diode is connected to a neutral point of the DC bus, a cathode of the first power diode is connected to a source of the fifth power electronic switch, and the fifth power electronic switch a drain of the tube is connected to a common end of the first power electronic switch tube and the second power electronic switch tube;
所述第二电力二极管的负极与所述直流母线的中性点相连接，所述第二电力二极管的正极与所述第六电力电子开关管的源极相连接，所述第六电力电子开关管的漏极与所述第三电力电子开关管和所述第四电力电子开关管的共同端相连接。a cathode of the second power diode is connected to a neutral point of the DC bus, a cathode of the second power diode is connected to a source of the sixth power electronic switch, and the sixth power electronic switch A drain of the tube is connected to a common end of the third power electronic switch tube and the fourth power electronic switch tube.
优选的，所述第二电力电子开关管和所述第三电力电子开关管的共同端形成所述有源中点钳位五电平逆变器的输出端而与所述滤波电感相连接。Preferably, a common end of the second power electronic switch tube and the third power electronic switch tube forms an output end of the active midpoint clamped five-level inverter and is connected to the filter inductor.
优选的，所述第一电力电子开关管、所述第二电力电子开关管、所述第三电力电子开关管、所述第四电力电子开关管、所述第五电力电子开关管、所述第六电力电子开关管均采用绝缘栅双极型晶体管。Preferably, the first power electronic switch tube, the second power electronic switch tube, the third power electronic switch tube, the fourth power electronic switch tube, the fifth power electronic switch tube, the The sixth power electronic switch tube uses an insulated gate bipolar transistor.
优选的，所述直流母线的正极通过第一反向阻断二极管而与所述Z源网络相连接，所述直流母线的负极通过第二反向阻断二极管而与所述Z源网络相连接。Preferably, the anode of the DC bus is connected to the Z source network through a first reverse blocking diode, and the cathode of the DC bus is connected to the Z source network through a second reverse blocking diode. .
由于上述技术方案运用，本发明与现有技术相比具有下列优点：本发明的Z源网络有源中点钳位五电平光伏并网逆变系统，结合Z源网络和多电平的优点，大大提高了光伏并网逆变器性能，能够减少光伏并网逆变系统滤波电感大小和逆变系统的开关频率，同时提高光伏并网逆变系统的可靠性。Due to the application of the above technical solutions, the present invention has the following advantages over the prior art: the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system of the present invention combines the advantages of the Z-source network and multi-level The performance of the photovoltaic grid-connected inverter is greatly improved, the filter inductance of the photovoltaic grid-connected inverter system and the switching frequency of the inverter system can be reduced, and the reliability of the photovoltaic grid-connected inverter system is improved.
附图说明DRAWINGS
附图1为本发明的光伏发电逆变系统的示意图。1 is a schematic view of a photovoltaic power generation inverter system of the present invention.
附图2为本发明的光伏发电逆变系统的状态1的示意图。2 is a schematic view of State 1 of the photovoltaic power generation inverter system of the present invention.
附图3为本发明的光伏发电逆变系统的状态2的示意图。3 is a schematic view of State 2 of the photovoltaic power generation inverter system of the present invention.
附图4为本发明的光伏发电逆变系统的状态3的示意图。4 is a schematic view of state 3 of the photovoltaic power generation inverter system of the present invention.
附图5为本发明的光伏发电逆变系统的状态4的示意图。Figure 5 is a schematic illustration of State 4 of a photovoltaic power generation inverter system of the present invention.
附图6为本发明的光伏发电逆变系统的状态5的示意图。Figure 6 is a schematic illustration of state 5 of a photovoltaic power generation inverter system of the present invention.
附图7为本发明的光伏发电逆变系统的状态6的示意图。Figure 7 is a schematic illustration of state 6 of a photovoltaic power generation inverter system of the present invention.
附图8为本发明的光伏发电逆变系统的状态7的示意图。Figure 8 is a schematic illustration of state 7 of a photovoltaic power generation inverter system of the present invention.
附图9为本发明的光伏发电逆变系统的状态8的示意图。Figure 9 is a schematic illustration of state 8 of a photovoltaic power generation inverter system of the present invention.
附图10为本发明的光伏发电逆变系统的状态9的示意图。Figure 10 is a schematic illustration of State 9 of a photovoltaic power generation inverter system of the present invention.
以上附图中：1、Z源网络；2、有源中点钳位五电平逆变器。In the above drawings: 1, Z source network; 2, active midpoint clamp five-level inverter.
具体实施方式detailed description
下面结合附图所示的实施例对本发明作进一步描述。The invention is further described below in conjunction with the embodiments shown in the drawings.
实施例一：如附图1所示，一种光伏发电逆变系统，它包括光伏电池板、与光伏电池板相连接的直流母线PN、连接于直流母线PN与电网之间的Z源网络有源中点钳位五电平光伏并网逆变系统。其中，P为直流母线正极、N为直流母线负极，直流母线上串接有两个分压滤波电容C 1、C 2，分压滤波电容C 1与分压滤波电容C 2的中点为直流母线PN的中性点O。 Embodiment 1 As shown in FIG. 1 , a photovoltaic power generation inverter system includes a photovoltaic panel, a DC bus PN connected to the photovoltaic panel, and a Z source network connected between the DC bus PN and the power grid. Source midpoint clamped five-level photovoltaic grid-connected inverter system. Wherein, P is the DC bus positive pole, N is the DC bus negative pole, and two voltage dividing filter capacitors C 1 and C 2 are connected in series on the DC bus, and the midpoint of the voltage dividing filter capacitor C 1 and the voltage dividing filter capacitor C 2 is DC. Neutral point O of bus PN.
Z源网络有源中点钳位五电平光伏并网逆变系统包括Z源网络1和有源中点钳位五电平逆变器2。Z源网络1与光伏电池板所连接的直流母线PN相连接，有源中点钳位五电平逆变器2与Z源网络1相连接，有源中点钳位五电平逆变器2的输出端经滤波电感L 3而与电网e g相连接。 The Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system includes a Z-source network 1 and an active midpoint clamped five-level inverter 2. The Z source network 1 is connected to the DC bus PN connected to the photovoltaic panel, the active midpoint clamped five-level inverter 2 is connected to the Z source network 1, and the active midpoint clamped five-level inverter an output terminal 2 via the filter inductor L 3 and is connected to the grid e g.
Z源网络1包括两个等值的电感L 1、L 2和两个等值的电容C 3、C 4，两个的电感L 1、L 2分别为第一电感L 1和第二电感L 2。电感L 1、L 2各自均具有两端，分别称为其a端和b端。第一电感L 1的a端与直流母线PN的正极P相连接，第一电感L 1的b端与有源中点钳位五电平逆变器2相连接，第二电感L 2的a端与直流母线PN的负极N相连接，第二电感L 2的b端与有源中点钳位五电平逆变器2相连接。一个电容C 3的两端分别连接在第一电感L 1的a端和第二电感L 2的b端之间，另一个电容C 4的两端分别连接在第一电感L 1的b端和第二电感L 2的a端之间，从而按照类X形构成Z源网络1。直流母线PN的正极P通过第一反向阻断二极管D1而与Z源网络1相连接，直流母线PN的 负极N通过第二反向阻断二极管D2而与Z源网络1相连接，即直流母线PN的正极P与第一反向阻断二极管D1的正极相连接，第一反向阻断二极管D1的负极与Z源网络1中第一电感L 1的a端相连接，直流母线PN的负极N与第二反向阻断二极管D2的负极相连接，第二反向阻断二极管D2的正极与Z源网络1中第二电感L 2的a端相连接。第一反向阻断二极管D1和第二反向阻断二极管D2在直通状态时起反向阻断作用。第一电感L 1的b端构成节点P1，第二电感L 2的b端构成节点N1。 The Z source network 1 includes two equivalent inductors L 1 , L 2 and two equivalent capacitors C 3 , C 4 , and the two inductors L 1 and L 2 are the first inductor L 1 and the second inductor L, respectively. 2 . The inductors L 1 and L 2 each have two ends, which are respectively referred to as an a terminal and a b terminal. The a terminal of the first inductor L 1 is connected to the positive pole P of the DC bus PN, the b terminal of the first inductor L 1 is connected to the active midpoint clamped five-level inverter 2, and the second inductor L 2 is a The terminal is connected to the negative pole N of the DC bus PN, and the b terminal of the second inductor L 2 is connected to the active midpoint clamped five-level inverter 2. Two ends of one capacitor C 3 are respectively connected between the a terminal of the first inductor L 1 and the b terminal of the second inductor L 2 , and the two ends of the other capacitor C 4 are respectively connected to the b terminal of the first inductor L 1 and Between the a ends of the second inductance L 2 , thereby forming the Z source network 1 in an X-like form. The anode P of the DC bus PN is connected to the Z source network 1 through the first reverse blocking diode D1, and the cathode N of the DC bus PN is connected to the Z source network 1 through the second reverse blocking diode D2, that is, DC PN positive bus P and the first reverse blocking diode D1 is connected to the positive electrode, the first reverse blocking diode D1 and the negative electrode 1 in the source network Z L a 1 of a first end of the inductor is connected to the DC bus PN The anode N is connected to the cathode of the second reverse blocking diode D2, and the anode of the second reverse blocking diode D2 is connected to the a terminal of the second inductor L 2 in the Z source network 1. The first reverse blocking diode D1 and the second reverse blocking diode D2 function as a reverse blocking in the through state. The b-end of the first inductor L 1 constitutes a node P1, and the b-end of the second inductor L 2 constitutes a node N1.
有源中点钳位五电平逆变器2包括第一电力电子开关管S1、第二电力电子开关管S2、第三电力电子开关管S3、第四电力电子开关管S4、第五电力电子开关管S5、第六电力电子开关管S6、第一电力二极管D3、第二电力二极管D4、钳位电容C 5。其中，第一电力电子开关管S1、第二电力电子开关管S2、第三电力电子开关管S3、第四电力电子开关管S4、第五电力电子开关管S5、第六电力电子开关管S6均采用绝缘栅双极型晶体管(Insulated Gate Bipolar Transistor，IGBT)。 The active midpoint clamped five-level inverter 2 includes a first power electronic switch tube S1, a second power electronic switch tube S2, a third power electronic switch tube S3, a fourth power electronic switch tube S4, and a fifth power electronics. switch S5, a sixth power electronic switch S6, a first power diode D3, a second power diode D4, the clamp capacitor C 5. The first power electronic switch tube S1, the second power electronic switch tube S2, the third power electronic switch tube S3, the fourth power electronic switch tube S4, the fifth power electronic switch tube S5, and the sixth power electronic switch tube S6 are both Insulated Gate Bipolar Transistor (IGBT) is used.
第一电力电子开关管S1、第二电力电子开关管S2、第三电力电子开关管S3、第四电力电子开关管S4依次串联，并连接在第一电感L 1的b端和第二电感L 2的b端之间，即连接在节点P1和节点N1之间。第一电力电子开关管和第二电力电子开关管的共同端构成节点P2，第三电力电子开关管和第四电力电子开关管的共同端构成节点N2。第一电力二极管D3与第五电力电子开关管S5相串联构成第一桥臂，第二电力二极管D4与第六电力电子开关管S6相串联构成第二桥臂，第一桥臂连接于直流母线PN的中性点O与第一电力电子开关管S1和第二电力电子开关管S2的共同端P2之间，第二桥臂连接于直流母线PN的中性点O与第三电力电子开关管S3和第四电力电子开关管S4的共同端N2之间，钳位电容C 5连接于第一电力电子开关管S1和第二电力电子开关管S2的共同端P2与第三电力电子开关管S3和第四电力电子开关管S4的共同端N2之间。 A first power electronic switch S1, the second power electronic switch S2, a third power electronic switch S3, fourth switch S4 power electronics in series, and connected to a first end of the inductor L 1 of B and the second inductor L Between the b ends of 2 , that is, between the node P1 and the node N1. The common end of the first power electronic switch tube and the second power electronic switch tube constitute a node P2, and the common end of the third power electronic switch tube and the fourth power electronic switch tube constitute a node N2. The first power diode D3 is connected in series with the fifth power electronic switch S5 to form a first bridge arm, and the second power diode D4 is connected in series with the sixth power electronic switch S6 to form a second bridge arm, and the first bridge arm is connected to the DC bus. Between the neutral point O of the PN and the common terminal P2 of the first power electronic switch S1 and the second power electronic switch S2, the second bridge arm is connected to the neutral point O of the DC bus PN and the third power electronic switch between the common terminal N2 of S3 and S4 is a fourth of the power electronic switches, clamp capacitor C 5 is connected to a common terminal P2 of the first power electronic switches S1 and S2 is a second power electronic switches of the third power electronic switch S3 Between the common terminal N2 of the fourth power electronic switch S4.
具体的，第一电力电子开关管S1的漏极与第一电感L 1的b端，即节点P1相连接，第一电力电子开关管S1的源极与第二电力电子开关管S2的漏极相连接，第二电力电子开关管S2的源极与第三电力电子开关管S3的漏极相连接，第三电力电子开关管S3的源极与第四电力电子开关管S4的漏极相连接，第四电力电子开关管S4的源极与第二电感L 2的b端，即节点N1相连接。 第一电力二极管D3的负极与直流母线PN的中性点O相连接，第一电力二极管D3的正极与第五电力电子开关管S5的源极相连接，第五电力电子开关管S5的漏极与第一电力电子开关管S1和第二电力电子开关管S2的共同端，即节点P2相连接。第二电力二极管D4的负极与直流母线PN的中性点O相连接，第二电力二极管D4的正极与第六电力电子开关管S6的源极相连接，第六电力电子开关管S6的漏极与第三电力电子开关管S3和第四电力电子开关管S4的共同端，即节点N2相连接。第二电力电子开关管S2和第三电力电子开关管S3的共同端，即第二电力电子开关管S2的源极形成有源中点钳位五电平逆变器2的输出端A而与滤波电感相L 3连接，再连接至电网e g。 Specifically, the power drain of the first electronic switch S1 and a first end of the inductor L b is 1, i.e. the node P1 is connected to the drain electrode of the first power source of the electronic switch S1 and a second power electronics the switch S2 Connected, the source of the second power electronic switch S2 is connected to the drain of the third power electronic switch S3, and the source of the third power electronic switch S3 is connected to the drain of the fourth power electronic switch S4. The source of the fourth power electronic switch S4 is connected to the b-end of the second inductor L 2 , that is, the node N1. The cathode of the first power diode D3 is connected to the neutral point O of the DC bus PN, the anode of the first power diode D3 is connected to the source of the fifth power electronic switch S5, and the drain of the fifth power electronic switch S5 is connected. The node common to the first power electronic switch S1 and the second power electronic switch S2, that is, the node P2 is connected. The cathode of the second power diode D4 is connected to the neutral point O of the DC bus PN, the anode of the second power diode D4 is connected to the source of the sixth power electronic switch S6, and the drain of the sixth power electronic switch S6 is connected. The common terminal of the third power electronic switch S3 and the fourth power electronic switch S4, that is, the node N2 is connected. The common terminal of the second power electronic switch S2 and the third power electronic switch S3, that is, the source of the second power electronic switch S2 forms the output A of the active midpoint clamped five-level inverter 2 The filter inductor phase L 3 is connected and then connected to the grid e g .
第一电力电子开关管S1和第四电力电子开关管S4承受的反向电压为直流母线PN电压的3/4，因此，为了减少第一电力电子开关管S1和第四电力电子开关管S4承受的反向电压，第一电力电子开关管S1包括串联的开关管S11、开关管S12，第四电力电子开关管包括串联的开关管S41、开关管S42。第一电力电子开关管S1中，开关管S11和开关管S12采用相同驱动信号，在第四电力电子开关管S4中，开关管S41和开关管S42采用相同驱动信号。开关管S11、开关管S12、开关管S41和开关管S42也均采用绝缘栅双极型晶体管。开关管S11的漏极构成第一电力电子开关管S1的漏极，开关管S11的源极与开关管S12的漏极相连接，开关管S12的源极构成第一电力电子开关管S1的源极。开关管S41的漏极构成第四电力电子开关管S4的漏极，开关管S41的源极与开关管S42的漏极相连接，开关管S42的源极构成第四电力电子开关管S4的源极。The reverse voltage of the first power electronic switch S1 and the fourth power electronic switch S4 is 3/4 of the DC bus PN voltage. Therefore, in order to reduce the first power electronic switch S1 and the fourth power electronic switch S4 The reverse voltage, the first power electronic switch S1 includes a switch S11 and a switch S12 connected in series, and the fourth power electronic switch includes a switch S41 and a switch S42 connected in series. In the first power electronic switch S1, the switch S11 and the switch S12 use the same drive signal. In the fourth power electronic switch S4, the switch S41 and the switch S42 use the same drive signal. The switch S11, the switch S12, the switch S41, and the switch S42 are also insulated gate bipolar transistors. The drain of the switch S11 constitutes the drain of the first power electronic switch S1, the source of the switch S11 is connected to the drain of the switch S12, and the source of the switch S12 constitutes the source of the first power electronic switch S1. pole. The drain of the switch S41 constitutes the drain of the fourth power electronic switch S4, the source of the switch S41 is connected to the drain of the switch S42, and the source of the switch S42 constitutes the source of the fourth power electronic switch S4. pole.
第一电力电子开关管S1、第二电力电子开关管S2、第三电力电子开关管S3、得到第四电力电子开关管S4均具有反并联二极管，而第五电力电子开关管S5、第六电力电子开关管S6没有反并联二极管。The first power electronic switch tube S1, the second power electronic switch tube S2, the third power electronic switch tube S3, and the fourth power electronic switch tube S4 each have an anti-parallel diode, and the fifth power electronic switch tube S5 and the sixth power The electronic switch S6 has no anti-parallel diodes.
上述Z源网络有源中点钳位五电平光伏并网逆变系统，以直流母线PN的电容中性点O点作为参考电压点(直流母线PN的电压为V dc)、并有源钳位电容C 5电压控制为V dc/4，逆变器输出电压与逆变器的电力电子开关信号(其中“1”代表电力电子开关管开通，“0”代表电力电子开关管关断)和直流母线电压V dc的关系为表1。其中“状态9”是Z源网络1直通状态。 The above-mentioned Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system uses the capacitor neutral point O of the DC bus PN as a reference voltage point (the voltage of the DC bus PN is V dc ), and the active clamp The bit capacitor C 5 voltage is controlled to V dc /4, the inverter output voltage and the power electronic switch signal of the inverter (where "1" represents the power electronic switch is turned on, "0" represents the power electronic switch is turned off) and The relationship between the DC bus voltage V dc is shown in Table 1. The "state 9" is the Z source network 1 through state.
表1 Z源网络有源中点钳位五电平逆变器输出电压与逆变器开关状态的关系Table 1 Relationship between output voltage of active-point clamped five-level inverter and inverter switching state of Z-source network
状态status S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 输出电压The output voltage
11 11 11 00 00 00 11 V dc/2 V dc /2
22 11 00 11 00 00 11 V dc/4 V dc /4
33 00 11 00 00 00 11 V dc/4 V dc /4
44 00 00 11 00 00 11 00
55 00 11 00 00 11 00 00
66 00 00 11 00 11 00 -V dc/4 -V dc /4
77 00 11 00 11 11 00 -V dc/4 -V dc / 4
88 00 00 11 11 11 00 -V dc/2 -V dc /2
99 11 11 11 11 00 00 直通状态Straight through state
状态1：第一电力电子开关管S1、第二电力电子开关管S2、第六电力电子开关管S6开通，第三电力电子开关管S3、第四电力电子开关管S4、第五电力电子开关管S5关断，此时的Z源网络有源中点钳位五电平光伏并网逆变系统中的电流流向如附图2所示，逆变输出电压为V dc/2。 State 1: first power electronic switch tube S1, second power electronic switch tube S2, sixth power electronic switch tube S6 open, third power electronic switch tube S3, fourth power electronic switch tube S4, fifth power electronic switch tube S5 is turned off. At this time, the current flow in the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system is as shown in Fig. 2, and the inverter output voltage is V dc /2.
状态2：第一电力电子开关管S1、第三电力电子开关管S3、第六电力电子开关管S6开通，第二电力电子开关管S2、第四电力电子开关管S4、第五电力电子开关管S5关断，此时的Z源网络有源中点钳位五电平光伏并网逆变系统中的电流流向如附图3所示，逆变输出电压为V dc/4。 State 2: the first power electronic switch tube S1, the third power electronic switch tube S3, the sixth power electronic switch tube S6 are turned on, the second power electronic switch tube S2, the fourth power electronic switch tube S4, and the fifth power electronic switch tube S5 is turned off. At this time, the current flow in the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system is shown in Figure 3. The inverter output voltage is V dc /4.
状态3：第二电力电子开关管S2、第六电力电子开关管S6开通，第二电力电子开关管S2、第三电力电子开关管S3、第四电力电子开关管S4、第五电力电子开关管S5关断，此时的Z源网络有源中点钳位五电平光伏并网逆变系统中的电流流向如附图4所示，逆变输出电压为V dc/4。 State 3: the second power electronic switch tube S2, the sixth power electronic switch tube S6 is turned on, the second power electronic switch tube S2, the third power electronic switch tube S3, the fourth power electronic switch tube S4, and the fifth power electronic switch tube S5 is turned off. At this time, the current flow in the active-point clamped five-level photovoltaic grid-connected inverter system of the Z-source network is as shown in FIG. 4, and the inverter output voltage is V dc /4.
状态4：第三电力电子开关管S3、第六电力电子开关管S6开通，第一电力电子开关管S1、第二电力电子开关管S2、第四电力电子开关管S4、第五电力电子开关管S5关断，此时的Z源网络有源中点钳位五电平光伏并网逆变系统中的电流流向如附图5所示，逆变输出电压为0。State 4: the third power electronic switch tube S3, the sixth power electronic switch tube S6 are turned on, the first power electronic switch tube S1, the second power electronic switch tube S2, the fourth power electronic switch tube S4, and the fifth power electronic switch tube S5 is turned off. At this time, the current flow in the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system is as shown in FIG. 5, and the inverter output voltage is zero.
状态5：第二电力电子开关管S2、第五电力电子开关管S5开通，第一电力电子开关管S1、第三电力电子开关管S3、第四电力电子开关管S4、第六电 力电子开关管S6关断，此时的Z源网络有源中点钳位五电平光伏并网逆变系统中的电流流向如附图6所示，逆变输出电压为0。State 5: the second power electronic switch tube S2, the fifth power electronic switch tube S5 is turned on, the first power electronic switch tube S1, the third power electronic switch tube S3, the fourth power electronic switch tube S4, and the sixth power electronic switch tube S6 is turned off. At this time, the current flow in the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system is as shown in FIG. 6, and the inverter output voltage is zero.
状态6：第三电力电子开关管S3、第五电力电子开关管S5开通，第一电力电子开关管S1、第二电力电子开关管S2、第四电力电子开关管S4、第六电力电子开关管S6关断，此时的Z源网络有源中点钳位五电平光伏并网逆变系统中的电流流向如附图7所示，逆变输出电压为-V dc/4。 State 6: the third power electronic switch tube S3 and the fifth power electronic switch tube S5 are turned on, the first power electronic switch tube S1, the second power electronic switch tube S2, the fourth power electronic switch tube S4, and the sixth power electronic switch tube S6 is turned off. At this time, the current flow in the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system is as shown in Fig. 7, and the inverter output voltage is -V dc /4.
状态7：第二电力电子开关管S2、第四电力电子开关管S4、第五电力电子开关管S5开通，第一电力电子开关管S1、第三电力电子开关管S3、第六电力电子开关管S6关断，此时的Z源网络有源中点钳位五电平光伏并网逆变系统中的电流流向如附图8所示，逆变输出电压为-V dc/4。 State 7: the second power electronic switch tube S2, the fourth power electronic switch tube S4, the fifth power electronic switch tube S5 are turned on, the first power electronic switch tube S1, the third power electronic switch tube S3, and the sixth power electronic switch tube S6 is turned off. At this time, the current flow in the active-point clamped five-level photovoltaic grid-connected inverter system of the Z-source network is as shown in Fig. 8. The inverter output voltage is -V dc /4.
状态8：第三电力电子开关管S3、第四电力电子开关管S4、第五电力电子开关管S5开通，第一电力电子开关管S1、第二电力电子开关管S2、第六电力电子开关管S6关断，此时的Z源网络有源中点钳位五电平光伏并网逆变系统中的电流流向如附图9所示，逆变输出电压为-V dc/2。 State 8: the third power electronic switch tube S3, the fourth power electronic switch tube S4, and the fifth power electronic switch tube S5 are turned on, the first power electronic switch tube S1, the second power electronic switch tube S2, and the sixth power electronic switch tube S6 is turned off. At this time, the current flow in the active-point clamped five-level photovoltaic grid-connected inverter system of the Z-source network is as shown in FIG. 9, and the inverter output voltage is -V dc /2.
状态9：第一电力电子开关管S1、第二电力电子开关管S2、第三电力电子开关管S3、第四电力电子开关管S4开通，第五电力电子开关管S5、第六电力电子开关管S6关断，为Z源网络1直通状态，此时的Z源网络有源中点钳位五电平光伏并网逆变系统中的电流流向如附图10所示。State 9: the first power electronic switch tube S1, the second power electronic switch tube S2, the third power electronic switch tube S3, the fourth power electronic switch tube S4, the fifth power electronic switch tube S5, and the sixth power electronic switch tube S6 is turned off, which is the Z-source network 1 through state. At this time, the current flow in the Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system is as shown in FIG.
上述方案是一种Z源网络1有源中点钳位五电平光伏并网逆变系统，它实现直流/直流变换器功能，输出电平个数为5，提高了光伏并网逆变器性能(电流纹波、效率、电压变化率等)；同时，逆变器开关管可以直通，提高了逆变器可靠性，有很好的应用前景。The above scheme is a Z-source network 1 active midpoint clamped five-level photovoltaic grid-connected inverter system, which realizes a DC/DC converter function, and the output level is 5, which improves the photovoltaic grid-connected inverter. Performance (current ripple, efficiency, voltage change rate, etc.); at the same time, the inverter switch tube can be directly connected, which improves the reliability of the inverter and has a good application prospect.
上述实施例只为说明本发明的技术构思及特点，其目的在于让熟悉此项技术的人士能够了解本发明的内容并据以实施，并不能以此限制本发明的保护范围。凡根据本发明精神实质所作的等效变化或修饰，都应涵盖在本发明的保护范围之内。The above embodiments are merely illustrative of the technical concept and the features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the present invention and to implement the present invention, and the scope of the present invention is not limited thereto. Equivalent variations or modifications made in accordance with the spirit of the invention are intended to be included within the scope of the invention.

Claims (8)

  1. 一种Z源网络有源中点钳位五电平光伏并网逆变系统，其特征在于：所述Z源网络有源中点钳位五电平光伏并网逆变系统包括与光伏电池板所连接的直流母线相连接的Z源网络、与所述Z源网络相连接的有源中点钳位五电平逆变器，所述有源中点钳位五电平逆变器的输出端经滤波电感而与电网相连接；A Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system, characterized in that: the Z source network active midpoint clamped five-level photovoltaic grid-connected inverter system comprises a photovoltaic panel a Z source network to which the connected DC bus is connected, an active midpoint clamped five-level inverter connected to the Z source network, and an output of the active midpoint clamped five-level inverter The filter is connected to the power grid through the filter inductor;
    所述Z源网络包括两个等值的电感和两个等值的电容，两个所述的电感分别为第一电感和第二电感；所述电感的两端分别为其a端和b端，所述第一电感的a端与所述直流母线的正极相连接，所述第一电感的b端与所述有源中点钳位五电平逆变器相连接，所述第二电感的a端与所述直流母线的负极相连接，所述第二电感的b端与所述有源中点钳位五电平逆变器相连接；一个所述电容的两端分别连接在所述第一电感的a端和所述第二电感的b端之间，另一个所述电容的两端分别连接在所述第一电感的b端和所述第二电感的a端之间。The Z source network includes two equivalent inductors and two equivalent capacitors, and the two inductors are respectively a first inductor and a second inductor; the two ends of the inductor are a terminal and a b terminal, respectively. The a terminal of the first inductor is connected to the positive pole of the DC bus, and the b terminal of the first inductor is connected to the active midpoint clamped five-level inverter, the second inductor The a terminal is connected to the negative pole of the DC bus, and the b terminal of the second inductor is connected to the active midpoint clamped five-level inverter; Between the a terminal of the first inductor and the b terminal of the second inductor, two ends of the other capacitor are respectively connected between the b terminal of the first inductor and the a terminal of the second inductor.
  2. 根据权利要求1所述的Z源网络有源中点钳位五电平光伏并网逆变系统，其特征在于：所述有源中点钳位五电平逆变器包括第一电力电子开关管、第二电力电子开关管、第三电力电子开关管、第四电力电子开关管、第五电力电子开关管、第六电力电子开关管、第一电力二极管、第二电力二极管、钳位电容；The Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system according to claim 1, wherein said active midpoint clamped five-level inverter comprises a first power electronic switch Tube, second power electronic switch tube, third power electronic switch tube, fourth power electronic switch tube, fifth power electronic switch tube, sixth power electronic switch tube, first power diode, second power diode, clamp capacitor ;
    所述第一电力电子开关管、所述第二电力电子开关管、所述第三电力电子开关管、所述第四电力电子开关管依次串联并连接在所述第一电感的b端和所述第二电感的b端之间，所述第一电力二极管与所述第五电力电子开关管相串联构成第一桥臂，所述第二电力二极管与所述第六电力电子开关管相串联构成第二桥臂，所述第一桥臂连接于所述直流母线的中性点与所述第一电力电子开关管和所述第二电力电子开关管的共同端之间，所述第二桥臂连接于所述直流母线的中性点与所述第三电力电子开关管和所述第四电力电子开关管的共同端之间，所述钳位电容连接于所述第一电力电子开关管和所述第二电力电子开关管的共同端与所述第三电力电子开关管和所述第四电力电子开关管的共同端之间。The first power electronic switch tube, the second power electronic switch tube, the third power electronic switch tube, and the fourth power electronic switch tube are sequentially connected in series and connected to the b end of the first inductor Between the b-ends of the second inductor, the first power diode and the fifth power electronic switch are connected in series to form a first bridge arm, and the second power diode is connected in series with the sixth power electronic switch Forming a second bridge arm, the first bridge arm being connected between a neutral point of the DC bus and a common end of the first power electronic switch tube and the second power electronic switch tube, the second a bridge arm is connected between a neutral point of the DC bus and a common end of the third power electronic switch tube and the fourth power electronic switch tube, and the clamp capacitor is connected to the first power electronic switch The common end of the tube and the second power electronic switch tube is between the common end of the third power electronic switch tube and the fourth power electronic switch tube.
  3. 根据权利要求2所述的Z源网络有源中点钳位五电平光伏并网逆变系统，其特征在于：所述第一电力电子开关管包括采用相同驱动信号且串联的开关管S11、开关管S12；所述第四电力电子开关管包括采用相同驱动信号且串联的开关管S41、开关管S42。The Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system according to claim 2, wherein the first power electronic switch tube comprises a switch tube S11 that uses the same drive signal and is connected in series, The switch tube S12; the fourth power electronic switch tube includes a switch tube S41 and a switch tube S42 that use the same drive signal and are connected in series.
  4. 根据权利要求2或3所述的Z源网络有源中点钳位五电平光伏并网逆变系统，其特征在于：所述第一电力电子开关管、所述第二电力电子开关管、所述第三电力电子开关管、得到第四电力电子开关管均具有反并联二极管。The Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system according to claim 2 or 3, wherein: the first power electronic switch tube, the second power electronic switch tube, The third power electronic switch tube and the fourth power electronic switch tube each have an anti-parallel diode.
  5. 根据权利要求2所述的Z源网络有源中点钳位五电平光伏并网逆变系统，其特征在于：所述第一电力电子开关管的漏极与所述第一电感的b端相连接，所述第一电力电子开关管的源极与所述第二电力电子开关管的漏极相连接，所述第二电力电子开关管的源极与所述第三电力电子开关管的漏极相连接，所述第三电力电子开关管的源极与所述第四电力电子开关管的漏极相连接，所述第四电力电子开关管的源极与所述第二电感的b端相连接；The Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system according to claim 2, wherein: the drain of the first power electronic switch tube and the b end of the first inductor Connected, the source of the first power electronic switch tube is connected to the drain of the second power electronic switch tube, the source of the second power electronic switch tube and the third power electronic switch tube a drain is connected, a source of the third power electronic switch is connected to a drain of the fourth power electronic switch, and a source of the fourth power electronic switch and a b of the second inductor Terminal connection
    所述第一电力二极管的负极与所述直流母线的中性点相连接，所述第一电力二极管的正极与所述第五电力电子开关管的源极相连接，所述第五电力电子开关管的漏极与所述第一电力电子开关管和所述第二电力电子开关管的共同端相连接；a cathode of the first power diode is connected to a neutral point of the DC bus, a cathode of the first power diode is connected to a source of the fifth power electronic switch, and the fifth power electronic switch a drain of the tube is connected to a common end of the first power electronic switch tube and the second power electronic switch tube;
    所述第二电力二极管的负极与所述直流母线的中性点相连接，所述第二电力二极管的正极与所述第六电力电子开关管的源极相连接，所述第六电力电子开关管的漏极与所述第三电力电子开关管和所述第四电力电子开关管的共同端相连接。a cathode of the second power diode is connected to a neutral point of the DC bus, a cathode of the second power diode is connected to a source of the sixth power electronic switch, and the sixth power electronic switch A drain of the tube is connected to a common end of the third power electronic switch tube and the fourth power electronic switch tube.
  6. 根据权利要求2所述的Z源网络有源中点钳位五电平光伏并网逆变系统，其特征在于：所述第二电力电子开关管和所述第三电力电子开关管的共同端形成所述有源中点钳位五电平逆变器的输出端而与所述滤波电感相连接。The Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system according to claim 2, wherein: the common end of the second power electronic switch tube and the third power electronic switch tube An output of the active midpoint clamped five-level inverter is formed to be coupled to the filter inductor.
  7. 根据权利要求2所述的Z源网络有源中点钳位五电平光伏并网逆变系统，其特征在于：所述第一电力电子开关管、所述第二电力电子开关管、所述第三电力电子开关管、所述第四电力电子开关管、所述第五电力电子开关管、所述第六电力电子开关管均采用绝缘栅双极型晶体管。The Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system according to claim 2, wherein: said first power electronic switch tube, said second power electronic switch tube, said The third power electronic switch tube, the fourth power electronic switch tube, the fifth power electronic switch tube, and the sixth power electronic switch tube all adopt an insulated gate bipolar transistor.
  8. 根据权利要求1所述的Z源网络有源中点钳位五电平光伏并网逆变系统，其特征在于：所述直流母线的正极通过第一反向阻断二极管而与所述Z源网络相连接，所述直流母线的负极通过第二反向阻断二极管而与所述Z源网络相连接。The Z-source network active midpoint clamped five-level photovoltaic grid-connected inverter system according to claim 1, wherein the anode of the DC bus is passed through the first reverse blocking diode and the Z source The network is connected, and the negative pole of the DC bus is connected to the Z source network through a second reverse blocking diode.
PCT/CN2018/080352 2017-03-24 2018-03-23 Z-source network active neutral point clamped five-level photovoltaic grid-connected inverter system WO2018171769A1 (en)

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