• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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    • 专利摘要:
    Dc-dc converter with bipolar output and use thereof for the connection of a distributed generation system to a bipolar dc network. The dc-dc converter (10) has an input for the connection of a dc source with monopolar output (9) and a bipolar voltage output, with the same voltages but with opposite polarities. The dc-dc converter (10) comprises three inductors (l1, l2, l3), four capacitors (c1, c2, c3, c4), two diodes (d1, d2) and a power switch (11) as a switching device. The main advantage of this topology is to use a single switching device to obtain a balanced bipolar output. In addition, the control terminal of the power switch (11) is connected to ground, which simplifies the design of the door drive device of the power switch (11). (Machine-translation by Google Translate, not legally binding)
    公开号:ES2608255A1
    申请号:ES201500753
    申请日:2015-10-06
    公开日:2017-04-06
    发明作者:Eladio DURÁN ARANDA；Salvador PÉREZ LITRÁN；María Bella FERRERA PRIETO
    申请人:Universidad de Huelva；
    IPC主号:
    专利说明:

    DESCRIPTION

    DC-DC converter with bipolar output and use of it to connect a distributed generation system to a bipolar DC network.
     5
    Technical sector

    The proposed DC-DC converter is applicable in bipolar DC networks since it allows the connection of a DC source with monopolar output to this type of networks. The present invention is of special application in the industrial and renewable energy sector. 10 In the first because this type of network is an alternative to the classic electrical system, currently of special interest in the industry. In this sector, the proposed converter allows you to control the voltage level and possible voltage imbalances of the DC network. On the other hand, in the renewable energy sector, the proposed scheme allows the connection of generation and storage systems to a bipolar 15 DC network reliably. The proposed topology is a solution for these applications with sufficient guarantees of reliability, quality and performance.

    Therefore, the proposed DC converter is indicated for exploitation by manufacturers of electronic equipment for the interconnection of distributed generation systems 20 with bipolar DC networks.

    Background of the invention

    The strong penetration of the distributed generation in the electrical system has led to the search for new configurations capable of guaranteeing a more flexible operation in order to improve its control, efficiency and reliability. In this new network concept, micro networks play a fundamental role. Whether in its DC, AC or combination form, these microgrids are an alternative to the traditional system that allows better system management when a large amount of generation 30 or small power storage is available.

    The use of DC technology was almost ruled out in energy transmission systems mainly because of the difficulty of adapting different voltage levels. Traditionally, DC power systems have been used in applications such as avionics, electric vehicles, naval facilities, rural areas, telecommunications infrastructures, long-distance power transmissions or by means of submarine cables and for the interconnection of AC networks of different frequencies.

    Today, the utility of DC networks is increasingly justified since many of the 40 devices that connect to the power grid need a DC-shaped power supply for operation. However, all these DC type loads require conversion of the AC power to DC for operation. Most of these conversion stages normally use inefficient rectifiers. On the other hand, most renewable energy units generate in the form of DC or have variable voltage / frequency outputs, so they need power electronic devices to adapt their production to the network conditions. These stages of DC-AC and AC-DC power conversion result in substantial energy losses. This justifies the use of DC micro networks since double conversion would be avoided in this way. The DC micro-network has mainly the following advantages over AC's: more efficiency and more power transmission, requires fewer drivers, is more stable, not
    It presents reactance in the line, its frequency is zero (which makes monitoring of the frequency unnecessary), there are no problems of transient stability, it does not generate electromagnetic interference and they have lower line resistance.

    In a DC microrred, the energy can be transmitted with a single conductor, two 5 conductors, or even three conductors, which leads to consider three types of configurations: monopolar, bipolar and homopolar. Of all these topologies, bipolar DC is one of the most used. This type of microrred has a conductor with positive polarity, another with negative polarity and a return (or neutral) conductor. In normal and equilibrium operation of the network, the current through the 10-return conductor is zero. It has two voltage levels, which allows a monopolar operation under conditions of failure. This topology has a higher technical complexity and greater cost than the monopolar DC link, but it has the following advantages in its favor: the current through the return conductor in normal operation is lower, so energy losses are reduced; when a fault occurs in one of the lines 15 the other continues to function normally; for the same transmission power, in a bipolar DC link, the current is half; and this topology allows to have two different voltage levels which is useful for some loads that consume high power since they can be connected to the higher level voltage so that the current consumed is reduced. twenty

    For the connection of distributed generation sources to a bipolar DC network, DC-DC converters are required when the source has its DC type output. Its function is to adapt the voltage levels between the source and the network. For these converters, different topologies with a single inductor have been proposed, such as the Buck, 25 Boost, ese ("Canonical Switching Cell") and Buck-Boost converters, and two inductor converters, such as Cuk, SEPIC ("Single Ended Primary lnductance Converter ") and Zeta. On the other hand, when multiple outputs and different voltage levels are required, combinations of basic converters have been proposed, such as Boost-Buck-Cascaded, Buck-Boost-Zeta, SEPIC-Boost and Zeta-Fiyback. 30

    In the case of connection of the distributed generation to bipolar networks, so far two or four switch converters have been used: half bridge or full bridge type.
     35
    Description of the invention

    The present invention relates to a DC-DC converter capable of generating bipolar voltage and with a novel topology suitable for the distributed generation connection to a bipolar DC network. Unlike the current DC-DC converters, which employ two or four switches, the topology proposed in the DC-DC converter of the present invention employs only one power switch, thereby reducing the complexity of the converter.

    The DC-DC converter with bipolar output has an input for connection with a DC source with monopolar output and a bipolar voltage output with a positive terminal and a negative terminal. The DC-DC converter comprises a power switch (e.g. an IGBT transistor, a MOSFET transistor), a first, second, third and fourth inductor, a first and a second capacitor, and a first and a second diode. These elements are interconnected with each other in such a way that: 50
    - When the power switch is activated, the power supplied to the input of the DC-DC converter by the DC source with monopolar output is stored in the first inductor, while the second and third inductors store energy due to the discharge of the first and second capacitor, respectively; and where during this activation interval of the power switch the first and second 5 diodes do not conduct and the energy supplied in the negative and positive output terminal of the DC-DC converter is provided by the discharge of the third and fourth capacitors, respectively.

    - When the power switch is deactivated, the first inductor recharges the first capacitor through the first diode and the second capacitor through the second diode, in turn causing the respective recharge of the third and fourth capacitors.

    The DC-DC converter can also comprise a snubber for safe operation of the power switch.

    Another aspect of the present invention relates to the use of the DC-DC converter described above for the connection of a distributed generation system to a bipolar DC network. twenty

    The DC-DC converter of the present invention has two outputs with the same voltage, having the same voltage conversion ratio but with opposite polarities. The main advantage of this topology is that it only uses a switching device or power switch to obtain a balanced bipolar output. 25 In addition, the control terminal of the power switch is grounded (to the negative of the input direct current source) which simplifies the design of the door excitation device of said power switch.

    Brief description of the drawings 30

    To complement the description made and for a better understanding of the characteristics of the invention, a list of figures is attached as an integral part of said description, where the following has been represented by way of illustration and not limitation: 35

    Figure 1 shows a typical topology of bipolar DC microrred.

    Figure 2 shows the DC-DC converter circuit object of the present invention.
     40
    Figure 3 shows a table to determine the values of the current and voltage of the DC-DC converter elements.

    Preferred Embodiment of the Invention
     Four. Five
    Figure 1 represents, by way of example, a bipolar DC micro-network topology 1. The micro-network is connected to an AC 2 public network through an AC-DC 3 converter. On the DC side the positive polarity conductors are shown + LVDC, the negative polarity conductors -LVDC and the return conductor R, which may or may not be grounded. The DC network can be connected, either directly or through converters 50 DC-DC 4, monopolar loads 5 or bipolar DC loads 6 (for example, a load
    industrial) between the + LVDC and -LVDC conductors. This type of bipolar DC loads 6, being connected to a higher voltage, requires a lower current for each of the conductors. On the other hand, AC 7, three-phase or single-phase loads can also be connected, via an inverter, DC-AC converter 8. The micro network 1 has at least one distributed generation unit 9 or distributed generator, each of them. 5 which is connected to the bipolar DC network through a DC-DC converter 10 like that of the present invention.

    The topology of the DC-DC converter 10 of the present invention is illustrated in detail in Figure 2, with the input and output terminals and the elements that make up the circuit. 10 The DC-DC power converter 10 consists of three inductors (L1, L2, L3), four capacitors (C1, C2, C3, C4), two diodes (D1, D2) and a power switch 11 as a device commutation. Although in the scheme the power switch 11 used is a transistor of the IGBT type, any other type of solid state switch such as a MOSFET or another can also be used. fifteen

    The DC-DC 10 converter circuit operates as explained below. When the power switch 11 is activated, the power supplied by the DC source with monopolar output (in the case of Figure 1, the distributed generation unit 9) is stored in a first inductor (L1). On the other hand, a second inductor (L2) and a third inductor (L3) also store energy due to the discharge of a first capacitor (C1) and a second capacitor (C2). During this interval a first diode (D1) and a second diode (D2) of free circulation do not conduct and the energy supplied to the loads is provided by the discharge of the output capacitors, third capacitor (C3) and fourth capacitor (C4) . When the power switch 11 is deactivated, the first inductor (L1) recharges the first (C1) and the second capacitor (C2) through the diodes (D1, D2), which also causes the third (C3) to recharge ) and fourth condenser (C4).

    The choice of the elements that make up the DC-DC converter 10 is based on the design power of it. For this, the values of the current and voltage for each of the circuit elements are taken into account. These values can be determined from the expressions detailed in the table in Figure 3.

    Regarding the control of the power switch 11, carried out through the voltage of the door control (Vcontrol), no preset control strategy or design is proposed, since there are multiple known control strategies applicable to DC-DC converters that They would also be valid for this topology. In the same way, measurement sensors are not included for the variables to be controlled in a bipolar DC application, such as the output voltages of the converter, since the essential thing 40 of the DC-DC converter 10 object of the present invention is not the control strategy but the specific topology of the converter and its application for the connection of distributed generation systems with bipolar DC networks.
    权利要求:
    Claims (5)
    [1]

    1. DC-DC converter with bipolar output, with an input for connection with a DC source with monopolar output (9) and a bipolar voltage output with a positive terminal (Vo +) and a negative terminal (Vo -), characterized by that the DC-DC 5 converter comprises the following elements:
    - a power switch (11);
    - a first (L1), a second (L2), a third (L3) and a fourth (L4) inductor; 10
    - a first (C1) and a second (C2) capacitor;
    - a first (D1) and a second (D2) diode;
     fifteen
    said elements being interconnected with each other in such a way that:
    When the power switch (11) is activated, the power supplied to the input of the DC-DC converter (10) by the DC source with monopolar output (9) is stored in the first inductor (L1), while the second ( L2) and the third (L3) inductor store 20 energy due to the discharge of the first (C1) and second (C2) capacitor, respectively; and where during this activation interval of the power switch (11) the first (D1) and the second (D2) diode do not conduct and the power supplied in the negative (Vo-) and positive (Vo +) output terminal of the DC converter -DC (10) is provided by the discharge of the third (C3) and fourth (C4) capacitor, 25 respectively;
    when the power switch (11) is deactivated, the first inductor (L1) recharges the first capacitor (C1) through the first diode (D1) and the second capacitor (C2) through the second diode (D2), causing turn the respective recharge of the third (C3) and 30 fourth (C4) capacitor.

    [2]
    2. DC-DC converter according to claim 1, characterized in that the power switch (11) is an IGBT transistor.
     35
    [3]
    3. DC-DC converter according to claim 1, characterized in that the power switch (11) is a MOSFET transistor.

    [4]
    4. DC-DC converter according to any of the preceding claims, characterized in that it comprises a snubber for the safe operation of the power switch 40 (11).

    [5]
    5. Use of the DC-DC converter with bipolar output according to any of the preceding claims for the connection of a distributed generation system (9) to a bipolar DC network (1). Four. Five
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    同族专利:
    公开号 | 公开日
    ES2608255B1|2017-11-07|
    引用文献:
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    US5815380A|1993-11-16|1998-09-29|Optimum Power Conversion, Inc.|Switching converter with open-loop primary side regulation|
    CN102035375A|2010-12-07|2011-04-27|江苏斯达工业科技有限公司|Switching boost type direct current converter|
    CN103633840A|2013-11-29|2014-03-12|华南理工大学|Single-switch high-gain boosting DC /DC converter|CN108599554A|2018-05-09|2018-09-28|重庆理工大学|A kind of bipolarity buck-boost direct current converter|
    法律状态:
    2017-11-07| FG2A| Definitive protection|Ref document number: 2608255 Country of ref document: ES Kind code of ref document: B1 Effective date: 20171107 |
    优先权:
    申请号 | 申请日 | 专利标题
    ES201500753A|ES2608255B1|2015-10-06|2015-10-06|DC-DC converter with bipolar output and use of it to connect a distributed generation system to a Bipolar DC network|ES201500753A| ES2608255B1|2015-10-06|2015-10-06|DC-DC converter with bipolar output and use of it to connect a distributed generation system to a Bipolar DC network|
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