Power conversion device

Abstract

A power conversion device according to an embodiment of the present invention includes: a first power conversion unit and a second power conversion unit that convert input power and output converted input power; a first passive element connected in series to the output end of the first power conversion unit; a second passive element connected in series to the output end of the first power conversion unit; and a switching unit connected to the output end of the first power conversion unit and the output end of the second power conversion unit to set the connection states of the output end of the first power conversion unit and the output end of the second power conversion unit.

Description

power conversion device

[0001] The present invention relates to a power conversion device, and more specifically, to a power conversion device with expandable capacity.

[0002] Interest in electric vehicle rapid chargers, energy storage systems (ESS), and solar power generation has been growing recently. With the continuous increase in power capacity used in recent applications, demand for power devices that simultaneously require high-voltage and high-current output is steadily increasing.

[0003] There is a need to develop power conversion devices that can meet these demands.

[0004] The technical problem to be solved by the present invention is an invention relating to a power conversion device with expandable capacity.

[0005] In order to solve the above technical problem, a power conversion device according to an embodiment of the present invention includes a first power conversion unit and a second power conversion unit that convert input power and output it; a first passive element connected in series to an output terminal of the first power conversion unit and a second passive element connected in series to an output terminal of the second power conversion unit; and a switching unit connected to the output terminal of the first power conversion unit and the output terminal of the second power conversion unit, and setting a connection state of the output terminal of the first power conversion unit and the output terminal of the second power conversion unit.

[0006] In addition, the switching unit operates in the first to third modes, and the switching unit is fixed in a first switching state so that the output terminal of the first power conversion unit and the output terminal of the second power conversion unit are connected in series in the first mode, is fixed in a second switching state so that the output terminal of the first power conversion unit and the output terminal of the second power conversion unit are connected in parallel in the second mode, and can perform a switching operation so that the first switching state and the second switching state are repeated at a predetermined ratio in the third mode.

[0007] In addition, the switching unit includes a plurality of switching elements, and among the plurality of switching elements, a plurality of switching elements that are in an on state in the first switching state can operate in synchronization in the third mode.

[0008] In addition, the switching unit includes a plurality of switching elements, and among the plurality of switching elements, a plurality of switching elements that are in an on state in the first switching state can operate with a phase difference in an interleaved manner in the third mode.

[0009] In addition, the switching unit may include a first switching element connected between the (+) output terminal of the first power conversion unit and the (+) output terminal of the second power conversion unit; a second switching element connected between the (+) output terminal of the second power conversion unit and the (-) output terminal of the first power conversion unit; and a third switching element connected between the (-) output terminal of the first power conversion unit and the (-) output terminal of the second power conversion unit.

[0010] In addition, the switching unit may include a fourth switching element connected between the (+) output terminal of the first power conversion unit and the (+) output terminal of the second power conversion unit; a fifth switching element and a sixth switching element connected in series between the (+) output terminal of the second power conversion unit and the (-) output terminal of the first power conversion unit; a seventh switching element connected between the (-) output terminal of the first power conversion unit and the (-) output terminal of the second power conversion unit; a first capacitor connected between a first node, which is a node between the fifth switching element and the sixth switching element, and the (+) output terminal of the first power conversion unit; and a second capacitor connected between the first node and the (-) output terminal of the second power conversion unit.

[0011] Additionally, the first passive element may include a first inductor, and the second passive element may include a second inductor.

[0012] In addition, the first inductor may be connected in series with the (+) output terminal of the first power conversion unit, and the second inductor may be connected in series with the (-) output terminal of the second power conversion unit.

[0013] In addition, the first inductor may be connected in series with the (-) output terminal of the first power conversion unit, and the second inductor may be connected in series with the (+) output terminal of the second power conversion unit.

[0014] Additionally, the first passive element may include a first coupling inductor, and the second passive element may include a second coupling inductor.

[0015] In addition, the first coupling inductor may include a third inductor connected in series with the (+) output terminal of the first power conversion unit; and a fourth inductor connected in series with the (-) output terminal of the first power conversion unit and coupled with the third inductor, and the second coupling inductor may include a fifth inductor connected in series with the (+) output terminal of the second power conversion unit; and a sixth inductor connected in series with the (-) output terminal of the second power conversion unit and coupled with the fifth inductor.

[0016] Additionally, the first passive element may include a seventh inductor connected in series with the (-) output terminal of the first power conversion unit, and the second passive element may include an eighth inductor connected in series with the (+) output terminal of the second power conversion unit and coupled with the seventh inductor.

[0017] According to embodiments of the present invention, power capacity can be expanded to high current or high voltage with a single circuit configuration. Furthermore, power capacity can be expanded to both high current and high voltage while maintaining continuous power transmission. Furthermore, two bypass modes are provided, minimizing losses due to switching losses and broadening the range of conditions under which bypass mode can be used. Furthermore, switching modes are provided, allowing variable gains for output voltage and current. By adjusting variable gains for output current / voltage expansion, operational flexibility can be enhanced.

[0018] Figure 1 is a block diagram of a power conversion device according to one embodiment of the present invention.

[0019] Figures 2 to 4 are block diagrams of a power conversion device according to an embodiment of the present invention.

[0020] FIGS. 5 to 17 are drawings for explaining examples of each configuration of a power conversion device according to an embodiment of the present invention.

[0021] Figures 18 to 20 are drawings for explaining the operation of a power conversion device according to an embodiment of the present invention.

[0022] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0023] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0024] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0025] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0026] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0027] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0028] And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, it may include not only cases where the component is 'connected', 'coupled', or 'connected' directly to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.

[0029] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," the meaning may include not only the upward direction but also the downward direction based on one component.

[0030] FIG. 1 is a block diagram of a power conversion device according to an embodiment of the present invention. FIGS. 2 to 4 are block diagrams of a power conversion device according to an embodiment of the present invention, FIGS. 5 to 17 are drawings for explaining examples of each component of a power conversion device according to an embodiment of the present invention, and FIGS. 18 to 20 are drawings for explaining the operation of a power conversion device according to an embodiment of the present invention.

[0031] A power conversion device (100) according to an embodiment of the present invention is composed of a first power conversion unit (120), a second power conversion unit (130), and a switching unit (160), and may include a first passive element (140), a second passive element (150), an input unit (110), an output unit (170), and a control unit (180). The power conversion device (100) according to an embodiment of the present invention may be a power conversion device that charges a vehicle battery, and may also be a power conversion device that receives power from various types of power sources and converts it.

[0032] The first power conversion unit (120) and the second power conversion unit (130) convert and output the input power. The first power conversion unit (120) and the second power conversion unit (130) receive the power input to the input unit (110), convert it, and output it. The first power conversion unit (120) and the second power conversion unit (130) can convert the input power into power to be supplied to a load connected to the output unit (170) and output it. Here, the load is a device that receives power and may include an electric vehicle. The first power conversion unit (120) and the second power conversion unit (130) may be a DC-DC converter, an AC-DC converter, or a DC-AC converter. In addition, the first power conversion unit (120) and the second power conversion unit (130) may be a boost converter, a buck converter, or a boost-buck converter, and may be a unidirectional or bidirectional converter. The first power conversion unit (120) and the second power conversion unit (130) may include an insulated converter, and may include a non-resonant insulated converter such as a Phase-shift full-bridge converter (PSFB), a Dual Active Bridge converter (DAB), a Forward converter, a Fly-back converter, etc., and may include a resonant insulated converter such as a Resonant LLC converter, a Resonant CLLC converter, a Resonant CLLLC converter, a Series-Resonant Converter, etc. It may also include a non-isolated converter.

[0033] In order to increase the range of output voltage or output current, a first power conversion unit (120) and a second power conversion unit (130) can be used. When the first power conversion unit (120) and the second power conversion unit (130) are connected in series, the range of the output voltage is expanded by the sum of the output voltages of each power conversion unit, but the range of the output current is not expanded. In this case, it is suitable for high-voltage output applications, but is disadvantageous in terms of conduction loss at high currents. When the first power conversion unit (120) and the second power conversion unit (130) are connected in parallel, the range of the output current is expanded by the sum of the output currents of each power conversion unit, but the range of the output voltage is not expanded. In this case, it is suitable for high-current output applications, but is disadvantageous in outputting high voltages.

[0034] In order to expand capacity suitable for applications requiring both high voltage and high current output, the power conversion device (100) according to an embodiment of the present invention includes a switching unit (160).

[0035] The switching unit (160) is connected to the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130), and can set the connection state of the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130). The switching unit (160) includes a plurality of switches, and can set the connection state of the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130) according to the on / off of the switches.

[0036] The output terminal of the first power conversion unit (120) may be connected to the switching unit (160) via a first passive element (140) that is connected in series, and the output terminal of the second power conversion unit (130) may be connected to the switching unit (160) via a second passive element (150) that is connected in series. As shown in FIG. 3, the first passive element (140) and the second passive element (150) may be connected to the first power conversion unit (120) and the second power conversion unit (130), respectively. In addition, as shown in FIG. 4, a capacitor may be included between the first power conversion unit (120) and the first passive element (140), and a capacitor may be included between the second power conversion unit (130) and the second passive element (150). A capacitor may also be included on the output side of the switching unit (160).

[0037] The first passive element (140) may be connected to the output terminal of the first power conversion unit (120). The first passive element (140) may include an inductor. At this time, it may include a single inductor (142, 143) connected in series to one of the (+) output terminal and the (-) output terminal of the first power conversion unit (120), may include a plurality of inductors (141) connected in series to both the (+) output terminal and the (-) output terminal of the first power conversion unit (120), and may include a plurality of inductors (144) connected in series to both the (+) output terminal and the (-) output terminal of the first power conversion unit (120) but coupled to each other. The first power conversion unit (120) may include an inductor connected in series to one of the (+) output terminal and the (-) output terminal and coupled with an inductor connected to the second power conversion unit (130). The first passive element (140) may include a capacitor, and may include a capacitor connected between the (+) output terminal and the (-) output terminal of the first power conversion unit (120). The first passive element (140) may include a capacitor and an inductor, and may include a capacitor connected between the (+) output terminal and the (-) output terminal of the first power conversion unit (120) and an inductor connected in series to the output terminal of the first power conversion unit (120). The first passive element (140) may allow the output of the first power conversion unit (120) to be stably input to the switching unit (160).

[0038] The second passive component (150) may be connected to the output terminal of the second power conversion unit (130). The second passive component (150) may include an inductor. At this time, it may include a single inductor (142, 143) connected in series to one of the (+) output terminal and the (-) output terminal of the second power conversion unit (130), may include a plurality of inductors (141) connected in series to both the (+) output terminal and the (-) output terminal of the second power conversion unit (130), and may include a plurality of inductors (144) connected in series to both the (+) output terminal and the (-) output terminal of the second power conversion unit (130) but coupled to each other. The second power conversion unit (130) may include an inductor connected in series to one of the (+) output terminal and the (-) output terminal and coupled with an inductor connected to the first power conversion unit (120). The second passive element (150) may include a capacitor, and may include a capacitor connected between the (+) output terminal and the (-) output terminal of the second power conversion unit (130). The second passive element (150) may include a capacitor and an inductor, and may include a capacitor connected between the (+) output terminal and the (-) output terminal of the second power conversion unit (130) and an inductor connected in series to the output terminal of the second power conversion unit (130). The second passive element (150) may allow the output of the second power conversion unit (130) to be stably input to the switching unit (160).

[0039] The control unit (180) can control the switching operation of the switching unit (160). The control unit (180) can include an MCU and can include one or more processors. The control unit (180) can detect the voltage, current, or power of the input unit (110) or the output unit (170) and control the switching unit (160) accordingly, and can control the switching unit (160) according to a user's setting or a command received from an external controller. The control unit (180) can control the power conversion of the first power conversion unit (120) and the second power conversion unit (130). The first power conversion unit (120) or the second power conversion unit (130) can include at least one switch, and the control unit (180) can control the corresponding switch to convert the input power.

[0040] The switching unit (160) can operate in the first to third modes. The switching unit (160) can be fixed in the first switching state so that the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130) are connected in series in the first mode, and can be fixed in the second switching state so that the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130) are connected in parallel in the second mode. The first mode and the second mode can be bypass modes that output the output of the first power conversion unit (120) and the output of the second power conversion unit (130) to the output unit (170).

[0041] In the first mode, the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130) are connected in series, and the two output voltages are combined to expand the range of the output voltage. To this end, the switching unit (160) can be fixed in the first switching state.

[0042] In the second mode, the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130) are connected in parallel, and the two output currents are combined to expand the range of the output current. To this end, the switching unit (160) can be fixed in the second switching state.

[0043] The switching unit (160) may operate in a third mode in which the switching operation is repeated so as to repeat the first switching state and the second switching state at a predetermined ratio, rather than being fixed to the first switching state or the second switching state. In the third mode, the output of the first power conversion unit (120) and the output of the second power conversion unit (130) may be repeatedly connected in series and in parallel. The operation may be performed so that the series connection time and the parallel connection time within one repeated cycle are at a predetermined ratio.

[0044] Through this, the output voltage range and output current range of the output output through the output unit (170) can be expanded simultaneously. The range of the output voltage can be expanded to a value between 0.5 and 1.0 times the sum of the output voltages of the two power conversion units. Here, 0.5 times the sum of the output voltages can be equal to the average. The range of the output current can be expanded to a value between 0.5 and 1.0 times the sum of the output currents of the two power conversion units. Here, 0.5 times the sum of the output currents can be equal to the average.

[0045] In the third mode, when the first switching state and the second switching state are repeated, but the ratio of the first switching state is higher than the ratio of the second switching state, the expansion of the range of the output voltage may be greater than the expansion of the range of the output current. Conversely, in the third mode, when the first switching state and the second switching state are repeated, but the ratio of the first switching state is lower than the ratio of the second switching state, the expansion of the range of the output voltage may be smaller than the expansion of the range of the output current. That is, the switching unit (160) can be controlled to vary the output depending on the type or characteristics of the power required by the load connected to the output unit (170).

[0046] The switching unit (160) includes a plurality of switching elements, and among the plurality of switching elements, a plurality of switching elements that are turned on in a first switching state can operate in synchronization in a third mode. Among the plurality of switching elements, a plurality of switching elements that are turned on in a second switching state can also operate in synchronization in a third mode. By adjusting the duty of the plurality of switches that are turned on in each switching state, the gain of the output according to the input can be varied.

[0047] The switching unit (160) includes a plurality of switching elements, and among the plurality of switching elements, a plurality of switching elements that are in an on state in a first switching state can operate with a phase difference in an interleaved manner in a third mode. Among the plurality of switching elements, a plurality of switching elements that are in an on state in a second switching state can also operate with a phase difference in an interleaved manner in the third mode. By adjusting the duty of the plurality of switches that are in an on state in each switching state, the gain of the output according to the input can be varied, and by operating in an interleaved manner, ripple can be reduced.

[0048] In order for the switching unit (160) to operate in the first to third modes, the switching unit (160) may include three switches or four or more switches. When three switches are included, the operation of the switching unit (160) can be implemented with only a small number of switches. When four switches are included, the required voltage withstand voltage of the switches can be lowered. For example, when the output is 1000 V, if three switches are used, a switch with a 1200 V specification must be used, but if four switches are used, a switch with a 650 V specification can be used. In addition, if four switches are used, a capacitor can be included to suppress the voltage spike of each switch.

[0049] When the switching unit (160) includes three switches, the switching unit (160) may include a first switching element (161), a second switching element (162), and a third switching element (163). As shown in FIG. 6, the first switching element (161) may be connected between the (+) output terminal (a) of the first power conversion unit (120) and the (+) output terminal (b) of the second power conversion unit (130), the second switching element (162) may be connected between the (+) output terminal (b) of the second power conversion unit (130) and the (-) output terminal (c) of the first power conversion unit (120), and the third switching element (163) may be connected between the (-) output terminal (c) of the first power conversion unit (120) and the (-) output terminal (d) of the second power conversion unit (130).

[0050] The first switching element (161) to the third switching element (163) may include at least one semiconductor switch, and may include a MOSFET or a MOSFET including a diode. In addition, one or more of the first switching element (161) to the third switching element (163) may include a diode.

[0051] As in 210 of Fig. 7, all three switching elements may include semiconductors, and as in 220, a MOSFET including a diode may be included for input / output bidirectional connection. Alternatively, as in 230, one MOSFET and two diodes may be included, and as in 240, two MOSFETs and one diode may be included. The connection direction of the diodes may be arranged so that the cathode is connected toward the (+) output terminal (a) side of the first power conversion unit (120), and the anode is connected toward the (-) output terminal (d) side of the second power conversion unit (130), as in Fig. 7.

[0052] When the switching unit (160) includes four switches, the switching unit (160) may include a fourth switching element (164), a fifth switching element (165), a sixth switching element (166), and a seventh switching element (167), and may include a first capacitor (168) and a second capacitor (169). As shown in FIG. 8, the fourth switching element (164) is connected between the (+) output terminal (a) of the first power conversion unit (120) and the (+) output terminal (b) of the second power conversion unit, the fifth switching element (165) and the sixth switching element (166) are connected in series between the (+) output terminal (b) of the second power conversion unit (130) and the (-) output terminal (c) of the first power conversion unit (120), and the seventh switching element (167) can be connected between the (-) output terminal (c) of the first power conversion unit (120) and the (-) output terminal (d) of the second power conversion unit (130). The first capacitor (168) may be connected between the first node, which is a node between the fifth switching element (165) and the sixth switching element (166), and the (+) output terminal (a) of the first power conversion unit (120), and the second capacitor (169) may be connected between the first node and the (-) output terminal (d) of the second power conversion unit.

[0053] As in 250 of Fig. 9, all four switching elements may include semiconductors, and as in 260, a MOSFET including a diode may be included for input / output bidirectional connection. As in 270 or 280, two MOSFETs and two diodes may be included. The connection direction of the diodes may be arranged so that the cathode is connected toward the (+) output terminal (a) side of the first power conversion unit (120), and the anode is connected toward the (-) output terminal (d) side of the second power conversion unit (130), as in Fig. 9.

[0054] The first passive component (140) may include a first inductor, and the second passive component (150) may include a second inductor. The first inductor may be connected in series with the (+) output terminal of the first power conversion unit (120), and the second inductor may be connected in series with the (-) output terminal of the second power conversion unit (130).

[0055] When the switching unit (160) includes three switches, as shown in FIG. 10, the first inductor L1 may be connected to the (+) output terminal of the first power conversion unit (120) and the first switching element S1, and the second inductor L2 may be connected to the (-) output terminal of the second power conversion unit (130) and the third switching element S3. The (-) output terminal of the first power conversion unit (120) may be connected to the node between the second switching element S2 and the third switching element S3, and the (+) output terminal of the second power conversion unit (130) may be connected to the node between the first switching element S1 and the second switching element S2.

[0056] When the switching unit (160) includes four switches, as shown in FIG. 14, the first inductor L1 may be connected to the (+) output terminal of the first power conversion unit (120) and the fourth switching element S1, and the second inductor L2 may be connected to the (-) output terminal of the second power conversion unit (130) and the seventh switching element S4. The (-) output terminal of the first power conversion unit (120) may be connected to the node between the sixth switching element S3 and the seventh switching element S4, and the (+) output terminal of the second power conversion unit (130) may be connected to the node between the fourth switching element S1 and the fifth switching element S2.

[0057] The first passive component (140) may include a first inductor, the second passive component (150) may include a second inductor, the first inductor may be connected in series with the (-) output terminal of the first power conversion unit (120), and the second inductor may be connected in series with the (-) output terminal of the second power conversion unit (130).

[0058] When the switching unit (160) includes three switches, as shown in FIG. 11, the first inductor L1 is connected to a node between the (-) output terminal of the first power conversion unit (120) and the second switching element S2 and the third switching element S3, the second inductor L2 is connected to a node between the (+) output terminal of the second power conversion unit (130) and the first switching element S1 and the second switching element S2, the (+) output terminal of the first power conversion unit (120) can be connected to the first switching element S1, and the (-) output terminal of the second power conversion unit (130) can be connected to the third switching element S3.

[0059] When the switching unit (160) includes four switches, as shown in FIG. 15, the first inductor L1 is connected to a node between the (-) output terminal of the first power conversion unit (120) and the sixth switching element S3 and the seventh switching element S4, the second inductor L2 is connected to a node between the (+) output terminal of the second power conversion unit (130) and the fourth switching element S1 and the fifth switching element S2, the (+) output terminal of the first power conversion unit (120) can be connected to the fourth switching element S1, and the (-) output terminal of the second power conversion unit (130) can be connected to the seventh switching element S4.

[0060] The first passive component (140) may include a first coupling inductor, and the second passive component (150) may include a second coupling inductor. By using a coupling inductor, inductor current ripple can be reduced.

[0061] The first coupling inductor may include a third inductor connected in series with the (+) output terminal of the first power conversion unit (120) and a fourth inductor connected in series with the (-) output terminal of the first power conversion unit (120) and coupled with the third inductor. The second coupling inductor may include a fifth inductor connected in series with the (+) output terminal of the second power conversion unit (130) and a sixth inductor connected in series with the (-) output terminal of the second power conversion unit (130) and coupled with the fifth inductor.

[0062] When the switching unit (160) includes three switches, as shown in FIG. 12, the third inductor L1 is connected to the (+) output terminal of the first power conversion unit (120) and the first switching element S1, the fourth inductor is an inductor coupled with the third inductor L1 and can be connected to a node between the (-) output terminal of the first power conversion unit (120) and the second switching element S2 and the third switching element S3. The fifth inductor L2 is connected to a node between the (+) output terminal of the second power conversion unit (130) and the first switching element S1 and the second switching element S2, and the sixth inductor is an inductor coupled with the fifth inductor L2 and can be connected to the (-) output terminal of the second power conversion unit (130) and the third switching element S3.

[0063] When the switching unit (160) includes four switches, as shown in FIG. 16, the third inductor L1 is connected to the (+) output terminal of the first power conversion unit (120) and the fourth switching element S1, and the fourth inductor can be connected to the node between the (-) output terminal of the first power conversion unit (120) and the sixth switching element S3 and the seventh switching element S4 as an inductor coupled with the third inductor L1. The second inductor L2 is connected to the node between the (+) output terminal of the second power conversion unit (130) and the fourth switching element S1 and the fifth switching element S2, and the sixth inductor can be connected to the (-) output terminal of the second power conversion unit (130) and the seventh switching element S4 as an inductor coupled with the fifth inductor L2.

[0064] The first passive element (140) may include a seventh inductor connected in series with the (-) output terminal of the first power conversion unit (120), and the second passive element (150) may include an eighth inductor connected in series with the (+) output terminal of the second power conversion unit (130) and coupled with the seventh inductor. By using a coupling inductor, inductor current ripple may be reduced.

[0065] When the switching unit (160) includes three switches, as shown in FIG. 13, the seventh inductor L1 is connected to a node between the (-) output terminal of the first power conversion unit (120) and the second switching element S2 and the third switching element S3, and the (-) output terminal of the first power conversion unit (120) can be connected to the first switching element S1. The eighth inductor L2 is connected to a node between the (+) output terminal of the second power conversion unit (130) and the first switching element S1 and the second switching element S2, and is coupled with the seventh inductor L1, and the (-) output terminal of the second power conversion unit (130) can be connected to the third switching element S3.

[0066] When the switching unit (160) includes four switches, as shown in FIG. 17, the seventh inductor L1 is connected to the node between the (-) output terminal of the first power conversion unit (120) and the sixth switching element S3 and the seventh switching element S4, and the (+) output terminal of the first power conversion unit (120) can be connected to the fourth switching element S1. The eighth inductor L2 is connected to the node between the (+) output terminal of the second power conversion unit (130) and the fourth switching element S1 and the fifth switching element S2, and is coupled with the seventh inductor L1, and the (-) output terminal of the second power conversion unit (130) can be connected to the seventh switching element S4.

[0067] As shown in Fig. 6, when there are three switches, in the first mode, the first switching element (161) and the third switching element (163) are turned off, and the second switching element (162) is turned on, so that a first switching state can be formed in which the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130) are connected in series. When the first passive element (140), the second passive element (150), and the switching unit (160) are implemented as shown in Fig. 18, as shown in 310, the first switching element S1 and the third switching element S3 are turned off, and the second switching element S2 is turned on, so that the (-) output terminal of the first power conversion unit (120) and the (+) output terminal of the second power conversion unit (130) can be connected through the first passive element L1 and the second passive element L2.

[0068] In the second mode, the first switching element (161) and the third switching element (163) are turned on, and the second switching element (162) is turned off, so that a second switching state can be formed in which the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130) are connected in parallel. As shown in 320 of FIG. 18, the first switching element S1 and the third switching element S3 are turned on, and the second switching element S2 is turned off, so that the (+) output terminal of the first power conversion unit (120) and the (+) output terminal of the second power conversion unit (130) are connected through the second passive element L2 and the first switching element S1, and the (-) output terminal of the first power conversion unit (120) and the (-) output terminal of the second power conversion unit (130) can be connected through the first passive element L1 and the third switching element S3.

[0069] As shown in Fig. 8, when there are four switches, in the first mode, the fourth switching element (164) and the seventh switching element (167) are turned off, and the fifth switching element (165) and the sixth switching element (166) are turned on, so that a first switching state can be formed in which the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130) are connected in series. When the first passive element (140), the second passive element (150), and the switching unit (160) are implemented as in FIG. 19, as in 330, the fourth switching element S1 and the seventh switching element S4 are turned off, the fifth switching element S2 and the sixth switching element S3 are turned on, and the (-) output terminal of the first power conversion unit (120) and the (+) output terminal of the second power conversion unit (130) can be connected through the first passive element L1, the sixth switching element S3, the fifth switching element S2, and the second passive element L2.

[0070] In the second mode, the fourth switching element (164) and the seventh switching element (167) are turned on, and the fifth switching element (165) and the sixth switching element (166) are turned off, so that a second switching state can be formed in which the output terminal of the first power conversion unit (120) and the output terminal of the second power conversion unit (130) are connected in parallel. As shown in 340 of FIG. 19, the fourth switching element S1 and the seventh switching element S4 are turned on, the fifth switching element S2 and the sixth switching element S3 are turned off, so that the (+) output terminal of the first power conversion unit (120) and the (+) output terminal of the second power conversion unit (130) are connected through the second passive element L2 and the fourth switching element S1, and the (-) output terminal of the first power conversion unit (120) and the (-) output terminal of the second power conversion unit (130) are connected through the first passive element L1 and the seventh switching element S4.

[0071] In the third mode, the first and second switching states can be repeated. When there are three switches, states 310 and 320 of Fig. 18 can be repeated, and each switch can operate as 410 of Fig. 20.

[0072] As shown in 410 of Fig. 20, a second switching state in which the first switching element S1 and the third switching element S3 are off and the second switching element S2 is on, and a first switching state in which the first switching element S1 and the third switching element S3 are on and the second switching element S2 is off can be repeated for each cycle. The gain can be varied by controlling the duty ratio of the first switching state and the second switching state.

[0073] In the case of four switches, states 330 and 340 of Fig. 19 can be repeated, and each switch can operate as 420 or 430 of Fig. 20. As in 420 of Fig. 20, a second switching state in which the fourth switching element S1 and the seventh switching element S4 are off and the fifth switching element S2 and the sixth switching element S3 are on, and a first switching state in which the fourth switching element S1 and the seventh switching element S4 are on and the fifth switching element S2 and the sixth switching element S3 are off can be repeated for each cycle. The gain can be varied by controlling the duty ratio of the first switching state and the second switching state. At this time, as in 420, the fourth switching element S1 and the seventh switching element S4 may be turned on and off simultaneously, and the fifth switching element S2 and the sixth switching element S3 may be turned on and off simultaneously in a synchronous manner, or as in 430, the fourth switching element S1 and the seventh switching element S4 may be turned on and off in an interleaved manner with a phase difference, and the fifth switching element S2 and the sixth switching element S3 may be turned on and off in an interleaved manner with a phase difference. At this time, the phase difference may be 180 degrees.

[0074] In Fig. 20, Ts is a switching period, D is a duty ratio, which can have a value between 0 and 1 (0 to 100%). Φshift is a phase shift, which can have a value between 0 and 360 degrees. At 430, D1 and D2 can have the same value. (D=D1=D2) In the interleaved method, the phase difference can be 180 degrees.

[0075] The relationship between input and output can be expressed as follows.

[0076] Vout / (Vin1+Vin2) = 1 / (2-D) or Iout / (Iin1+Iin2) = (2-D) / 2

[0077] Here, Vout represents the output voltage of the output unit (170), Iout represents the output current of the output unit (170), Vin1 and Vin2 represent the output voltage of each power conversion unit, and Iin1 and Iin2 represent the output current of each power conversion unit.

[0078] Since D has a value between 0 and 1, Vout and Iout can have a value between 0.5 and 1.0 times the sum of the output voltages or the sum of the output currents of each power conversion unit.

[0079] The method of expanding power capacity by connecting in series or parallel can only implement operations where D corresponds to 0 or 1. That is, it can have a value of either 0.5 or 1.0 times the sum of the output voltages or the sum of the output currents of each power conversion unit.

[0080] The control unit (180) can control the switching unit (160) in a complex manner the first mode, the second mode, and the third mode, and can continuously output the output voltage and output current of the power conversion device without interruption through the second mode.

[0081] As described above, by controlling the switching unit (160) to change the connection state between the output of the first power conversion unit (120) and the output terminal of the second power conversion unit (130), power capacity expansion to high current or high voltage is possible with one circuit configuration. In addition, power capacity expansion to both high current and high voltage is possible while maintaining continuous power transmission. In addition, by providing two bypass modes, loss due to switching loss can be minimized, and there is an advantage in that the range of conditions under which the bypass mode can be used is wide. In addition, by providing a switching mode, the gain of the output voltage and current can be varied. By adjusting the variable gain in the expansion of the output current / voltage, flexibility of operation can be increased.

[0082] Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from the essential characteristics of the above-described description. Therefore, the disclosed methods should be considered illustrative rather than restrictive. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. A first power conversion unit and a second power conversion unit that convert and output input power; A first passive element connected in series to the output terminal of the first power conversion unit and a second passive element connected in series to the output terminal of the second power conversion unit; and A power conversion device including a switching unit connected to the output terminal of the first power conversion unit and the output terminal of the second power conversion unit, and setting the connection state of the output terminal of the first power conversion unit and the output terminal of the second power conversion unit.

2. In paragraph 1, The above switching unit operates in the first to third modes, The above switching part, In the above first mode, the output terminal of the first power conversion unit and the output terminal of the second power conversion unit are fixed in the first switching state so as to be connected in series, In the second mode, the output terminal of the first power conversion unit and the output terminal of the second power conversion unit are fixed in the second switching state so as to be connected in parallel, A power conversion device that performs a switching operation to repeat the first switching state and the second switching state at a predetermined ratio in the third mode.

3. In paragraph 2, The above switching unit includes a plurality of switching elements, Among the plurality of switching elements, the plurality of switching elements that are in the on state in the first switching state are: A power conversion device that operates in synchronization with the third mode.

4. In paragraph 2, The above switching unit includes a plurality of switching elements, Among the plurality of switching elements, the plurality of switching elements that are in the on state in the first switching state are: A power conversion device that operates with a phase difference in an interleaved manner in the third mode.

5. In paragraph 1, The above switching part, A first switching element connected between the (+) output terminal of the first power conversion unit and the (+) output terminal of the second power conversion unit; A second switching element connected between the (+) output terminal of the second power conversion unit and the (-) output terminal of the first power conversion unit; and A power conversion device including a third switching element connected between the (-) output terminal of the first power conversion unit and the (-) output terminal of the second power conversion unit.

6. In paragraph 1, The above switching part, A fourth switching element connected between the (+) output terminal of the first power conversion unit and the (+) output terminal of the second power conversion unit; A fifth switching element and a sixth switching element connected in series between the (+) output terminal of the second power conversion unit and the (-) output terminal of the first power conversion unit; A seventh switching element connected between the (-) output terminal of the first power conversion unit and the (-) output terminal of the second power conversion unit; A first capacitor connected between a first node, which is a node between the fifth switching element and the sixth switching element, and the (+) output terminal of the first power conversion unit; and A power conversion device including a second capacitor connected between the first node and the (-) output terminal of the second power conversion unit.

7. In paragraph 1, The above first passive component comprises a first inductor, The second passive component is a power conversion device including a second inductor.

8. In paragraph 7, The above first inductor is connected in series with the (+) output terminal of the first power converter, A power conversion device in which the second inductor is connected in series with the (-) output terminal of the second power conversion unit.

9. In paragraph 1, The above first passive component comprises a first coupling inductor, The second passive component comprises a second coupling inductor, The above first coupling inductor is, A third inductor connected in series with the (+) output terminal of the first power converter; and It includes a fourth inductor connected in series with the (-) output terminal of the first power converter and coupled with the third inductor, The above second coupling inductor is, A fifth inductor connected in series with the (+) output terminal of the second power converter; and A power conversion device including a sixth inductor connected in series with the (-) output terminal of the second power conversion unit and coupled with the fifth inductor.

10. In paragraph 1, The above first passive component includes a seventh inductor connected in series with the (-) output terminal of the first power converter, A power conversion device, wherein the second passive element is connected in series with the (+) output terminal of the second power conversion unit and includes an eighth inductor coupled with the seventh inductor.

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