TWI729333B - Power converter with common dc power source and power supply apparatus having the same - Google Patents

Abstract

A power converter with a common DC power source includes a DC power source and at least two power modules. Each power module is coupled with each other and coupled to the DC power source. Each power module includes a coupled inductive component coupled to the DC power source, a DC output conversion unit coupled to the coupled inductive component, and a capacitor assembly having a coupling point. By using the coupled inductive components, it is to solve the problem of the current flowing between the power modules due to the commonly-connected coupling points.

Description

Power converter and power supply device for common DC power supply

The present invention relates to a power converter and a power supply device, in particular to a power converter with a common DC power supply and a power supply device with the power converter with the common DC power supply.

Uninterruptible Power System (UPS) is a device used to continuously provide backup AC or DC power supply to load equipment such as electrical appliances in the event of a power grid abnormality or power outage, so as to maintain the normal operation of electrical appliances. Under normal circumstances, uninterrupted power supply devices are used to maintain uninterrupted power supply for key commercial equipment or precision instruments such as computers and servers to prevent data loss, communication interruption, or loss of control of the device. In actual use, based on the consideration of improving the reliability of power supply or the required power, two or more UPSs can be used for parallel coupling to form a dual or multiple UPS architecture. Furthermore, in order to save the volume occupied by rechargeable batteries, such as storage batteries, two or more UPSs can use a single rechargeable battery as a backup power source.

For the DC output stage (DC output converter), based on meeting the requirements of high output voltage and withstand voltage, two capacitors can be connected in series (at the coupling point) to provide a dual bus (Bus) DC output , A plurality of DC output converters realize the operation of parallel power supply by connecting these coupling points in common. Due to the common connection of these coupling points, in the case of a common DC power supply, a current return path will be formed between different DC output converters, that is, the input current It will flow through one set of DC output converters through another set of DC output converters to cause current to flow back, causing another set of DC output converters to over-current.

If you want to suppress or improve the current return situation, if you add inductance elements and independently control the inductance current of each path, or add a switching element, the return current can be cut off by turning off the switching element, although the conversion of different DC outputs can be inhibited. The problem of current return between the devices, but the added inductance element and/or switching element and the corresponding control circuit not only increase the cost, but also increase the complexity and difficulty of circuit control.

For this reason, how to design a power converter and a power supply device with a common DC power supply to solve the aforementioned technical problems is an important subject studied by the inventor of this case.

The object of the present invention is to provide a power converter with a common DC power supply, which solves the problem of current backflow between different DC output converters caused by the coupling of the coupling points.

In order to achieve the foregoing objective, the power converter of the common DC power supply proposed in the present invention includes a DC power supply and at least two power modules coupled to the DC power supply. Each power module is coupled to each other, and includes a coupled inductance element, a DC output conversion unit, and a capacitor bank. The coupled inductance element is coupled to the DC power supply. The DC output conversion unit is coupled to the coupled inductance element. The capacitor bank is coupled to the DC output conversion unit, the capacitor bank has two capacitors coupled in series, and there is a coupling point between the two capacitors. The at least two power modules are coupled to each other through coupling points.

With the proposed power converter of the common DC power supply, the problem of current flow between the power modules caused by the coupling of the coupling points can be solved, so that the circuit cost is reduced, and the complexity and difficulty of circuit control are simplified. .

Another object of the present invention is to provide a power supply device that solves the problem of current backflow between different DC output converters caused by the coupling of the coupling points.

In order to achieve the foregoing objective, the power supply device proposed by the present invention is applied to supply power to a load. The power supply device includes the aforementioned power converter of the common DC power supply and at least two DC input conversion units. Each DC input conversion unit has an input end and an output end, the input end is correspondingly coupled to each DC output conversion unit and each capacitor group, and the output end is coupled to the load.

With the proposed power supply device, it is possible to solve the problem of current flow between the power supply modules caused by the coupling of the coupling points, so as to reduce the circuit cost and simplify the complexity and difficulty of circuit control.

1: Power module

11: Coupling inductance element

12: DC output conversion unit

13: Capacitor bank

B1: DC power supply

C1, C1’, C1”: the first capacitor

C2, C2’, C2”: second capacitor

D1, D1’, D1”: the first diode

D2, D2’, D2": second diode

D3, D3’, D3": the third diode

D4, D4’, D4”: the fourth diode

Q1, Q1’, Q1": the first power switch

Q2, Q2’, Q2": the second power switch

P1, P1’, P1”: input inductance

N, N’, N”: coupling point

I1, I1’, I1”: first current

I2, I2’, I2”: second current

IN_1: the first input

OUT_1: the first output terminal

IN_2: second input

OUT_2: second output terminal

100: iron core

14, 14’: DC input conversion unit

L1: The first power output terminal

L2: The second power output terminal

L": Firewire output terminal

N”’: Neutral end

B_IN: Input terminal

B_OUT: output terminal

Fig. 1 is a circuit diagram of an embodiment of the power converter of the common DC power supply of the present invention; Fig. 2 is a circuit diagram of another embodiment of the power converter of the common DC power supply of the present invention; Fig. 3 is the power conversion of the common DC power supply of the present invention Fig. 4 is a schematic block diagram of the functional architecture of the first embodiment of the power converter of the common DC power supply applied to the uninterruptible power supply device; and Fig. 5 is the block diagram of the common DC power supply of the present invention. The functional block diagram of the second embodiment of the power converter applied to the uninterruptible power supply device.

The following is a specific embodiment to illustrate the implementation of the present invention. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied by other different specific examples, and various details in the specification of the present invention can also be modified and changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the structure, ratio, size, number of components, etc. shown in the drawings in this specification are only used to match the content disclosed in the specification for the understanding and reading of those familiar with this technology, and are not intended to limit the scope of the present invention. The limited conditions of implementation do not have any technical significance. Any structural modification, proportional relationship change, or size adjustment should fall within the scope of the present invention without affecting the effects that can be produced and the goals that can be achieved by the present invention. The technical content disclosed by the invention can be covered. The technical content and detailed description of the present invention are described below in conjunction with the drawings.

Please refer to Figures 1 and 3, where Figure 1 is a circuit diagram of an embodiment of the power converter of the common DC power supply of the present invention; Figure 3 is a schematic diagram of the coupled inductance element of the power converter of the common DC power supply of the present invention .

In an embodiment of the power converter of the common DC power supply of the present invention, it includes: a DC power supply B1 and at least two power supply modules 1. In this embodiment, there are two power supply modules 1. Among them, two power modules 1 are coupled to a DC power source B1; each power module 1 is coupled to each other and includes a coupled inductance element 11, a DC output conversion unit 12, and a capacitor group 13.

Furthermore, the coupled inductive element 11 is coupled to the DC power source B1, and the first current I1 flows into the coupled inductive element 11 and flows back to the DC power source B1 to a second current I2. The DC output conversion unit 12 is coupled to the coupled inductance element 11, the DC output conversion unit 12 receives the first current I1, and the second current I2 flows back to the DC power supply B1 through the DC output conversion unit 12. Capacitor bank 13 is coupled to the DC output conversion unit 12, and the capacitor group 13 has two capacitors (C1 and C2 as shown in FIG. 1) coupled in series, and the two capacitors are respectively a first capacitor C1 and a second capacitor C2. There is a coupling point N between the first capacitor C1 and the second capacitor C2, that is, the first capacitor C1 and the second capacitor C2 are coupled to the coupling point N, and the coupling point N can be used to connect the neutral of the AC power system Line end. Wherein, the power modules 1 are coupled to each other through the coupling points N. In this embodiment, there are two coupling points N in total. The first current I1 flowing out of the DC power supply B1 and the second current I2 flowing back to the DC power supply B1 have the same current magnitude. In this embodiment, the DC power supply B1 can be a lithium battery or a lead-acid battery, but the present invention is not limited by this.

Furthermore, as shown in FIGS. 1 and 3, the coupled inductance element 11 includes a first input terminal IN_1, a second input terminal IN_2, a first output terminal OUT_1, and a second output terminal OUT_2. The first input terminal IN_1 and the second output terminal OUT_2 are respectively coupled to the DC power supply B1, and the first output terminal OUT_1 and the second input terminal IN_2 are respectively coupled to the DC output conversion unit 12. Wherein, the first input terminal IN_1 and the second output terminal OUT_2 have the same polarity (as indicated by the two black dots on the left side of the coupled inductance element 11 in FIG. 1). The second input terminal IN_2 and the first output terminal OUT_1 have the same polarity (as indicated by no black dots on the right side of the coupled inductance element 11 in FIG. 1). The first current I1 flows into the coupled inductance element 11 through the first input terminal IN_1, flows out of the coupled inductance element 11 through the first output terminal OUT_1, and flows to the DC output conversion unit 12. The second current I2 flows into the coupled inductance element 11 through the second input terminal IN_2, flows out of the coupled inductance element 11 through the second output terminal OUT_2, and flows to the DC power supply B1. As mentioned above, by using the coupled inductance element 11, the first current I1 flowing into the first input terminal IN_1 of the coupled inductance element 11 and the second current I2 flowing out of the second output terminal OUT_2 of the coupled inductance element 11 are both current The same size, so that the current will not Through the coupling point N to flow to other power modules 1, the current backflow between the power modules caused by the coupling of the coupling points N to each other can be solved, which causes the current overcurrent of the power modules to occur.

As shown in FIG. 3, in this embodiment, the coupled inductance element 11 is a common mode choke, or common mode choke, which has a core 100 and a core 100 opposite to the winding direction. Two coils, wherein the first input terminal IN_1 and the first output terminal OUT_1 are the same coil, and the second input terminal IN_2 and the second output terminal OUT_2 are the same coil.

In detail, the first input terminal IN_1 of the coupled inductance element 11 is coupled to an anode of the DC power source B1, and the power modules 1 are coupled to each other through the first input terminal IN_1; the second output terminal OUT_2 is coupled to the DC power source B1 A negative electrode of, and the power modules 1 are coupled to each other through the second output terminal OUT_2. In addition, the DC output conversion unit 12 can be further coupled to an AC power supply (not shown in the figure). Therefore, the DC power supply B1 or the AC power supply can be switchably coupled to the DC output conversion unit 12, for example, through a controller controlling a switch to switch DC The power source B1 or AC power source is coupled to the DC output conversion unit 12, and the DC output conversion unit 12 converts the DC power source B1 or the AC power source into a DC output power source to provide uninterrupted power supply to the load. In this embodiment, the DC output conversion unit 12 is used to convert DC input or AC input power to provide a DC power output. Therefore, the DC output conversion unit 12 can be controlled as a DC-DC output conversion unit (DC-DC). converter), which receives DC input power and converts it to DC output power, or controls it as an AC-DC converter (AC-DC converter), receives AC input power and converts it to DC output power.

As shown in Figure 1, the DC output conversion unit 12 includes an input inductor P1, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, and a first power Rate switch Q1 and the second power switch Q2. The input inductor P1 is coupled to the first output terminal OUT_1 of the coupled inductance element 11. The first diode D1 is coupled to the second diode D2 at the first common junction and forms a first branch, wherein one end of the input inductor P1 is coupled to the first common junction. The second power switch Q2 and the first power switch Q1 are coupled to a second common node and form a second branch, wherein the second branch is coupled to the first branch in parallel, and the second common node is coupled to Point N. The third diode D3 is coupled to the first diode D1 and the first power switch Q1; the fourth diode D4 is coupled to the second diode D2 and the second power switch Q2. The second diode D2, the second power switch Q2, and the fourth diode D4 are coupled to the second input terminal IN_2 of the coupled inductance element 11. The third diode D3 is coupled between the first diode D1, the first power switch Q1 and the first capacitor C1 of the capacitor group 13; the fourth diode D4 is coupled to the second diode D2, the first capacitor C1 Between the second power switch Q2 and the second capacitor C2 of the capacitor group 13. Among them, the first power switch Q1 and the second power switch Q2 can be one of a metal oxide semiconductor field effect transistor (MOSFET), a bipolar junction transistor (BJT), and an insulated gate bipolar transistor (IGBT). However, the present invention is not limited by this. The DC output conversion unit 12 of this embodiment is only one possible circuit, but it is not intended to limit the present invention. It should be understood that other conversion circuits whose output has a coupling point N between two capacitors known to those skilled in the art can be used. Apply the present invention.

Please refer to FIG. 2, which is a circuit diagram of another embodiment of the power converter of the common DC power supply of the present invention, which is roughly the same as the embodiment shown in FIG. 1, except that it has a plurality of power modules 1, and I1 And I1' and I1", I2 and I2' and I2", P1 and P1' and P1", D1 and D1' and D1", D2 and D2' and D2", D3 and D3' and D3", D4 and D4 'And D4", C1 and C1' and C1", C2 and C2' and C2", Q1 and Q1' and Q1", Q2 and Q2' and Q2", N and N'and N" are all the same or similar Circuit configuration.

Please refer to FIG. 4 and FIG. 5, where FIG. 4 is a functional block diagram of the first embodiment of the power converter of the common DC power supply applied to the power supply device; and FIG. 5 is the block diagram of the common DC power supply of the present invention The functional structure block diagram of the second embodiment of the power converter applied to the power supply device.

As shown in FIG. 4, the first embodiment of the power supply device of the present invention is applied to provide uninterrupted power supply to a load (not shown in the figure), including the aforementioned common DC power supply converter (including DC Power supply B1 and at least two power supply modules 1), wherein each DC output conversion unit 12 is not only coupled to DC power supply B1 through coupling inductance element 11, but also to AC power supply (not shown in the figure) through a switching device, Wherein, one end of the AC power source (for example, the live wire terminal) can be coupled between the coupled inductance element 11 and the DC output conversion unit 12, and the other end of the AC power source (for example, the neutral terminal) is coupled to the coupling point N And at least two DC input conversion units 14, each DC input conversion unit 14 has an input terminal B_IN and an output terminal B_OUT, the input terminal B_IN is coupled to the DC output conversion unit 12 and the capacitor group 13 of the power converter of the common DC power supply; The terminal B_OUT is coupled to the load. In the present invention, each DC input conversion unit 14 is correspondingly coupled to each coupled inductance element 11, each DC output conversion unit 12, and each capacitor group 13 to form a power conversion module, and the power conversion modules are connected in parallel with each other.

If the AC power source is normal, the controller controls to switch the AC power source to be coupled to the DC output conversion unit 12 so that the AC power source performs power conversion through the DC output conversion unit 12 and the DC input conversion unit 14 to supply power to the load. Conversely, when the AC power source is abnormal, the controller controls to switch the DC power source B1 to the DC output conversion unit 12 through the coupling inductance element 11, so that the DC power source B1 passes through the DC output conversion unit 12 and the DC input conversion unit 14 Perform power conversion to supply power to the load. In this way, when the DC power supply B1 is supplying power, the coupling point N is the coupled inductance element 11, and no current flows back.

As shown in FIG. 4, when the load is a DC load, the DC input conversion unit 14 used is a DC-to-DC converter (DC-to-DC converter) for receiving the DC power provided by the capacitor bank 13, and Convert this DC power supply into a DC power supply output to supply power to the DC load. Each DC input conversion unit 14 provides a first power output terminal L1 and a second power output terminal L2 for load coupling. The first power output terminal L1 and the second power output terminal L2 have different polarities (for example, one is positive, The other is the negative pole), and the DC input conversion units 14 are respectively coupled to each other through the first power output terminal L1 and the second power output terminal L2 to achieve output parallel connection. Wherein, the coupling connection between the coupling points N and N'is independent of the first power output terminal L1 and the second power output terminal L2.

If the AC power supply is normal, the AC power supply supplies power to the load through the DC output conversion unit 12, the capacitor bank 13, the DC input conversion unit 14, and the first power output terminal L1 and the second power output terminal L2. If the AC power supply is abnormal, the DC power supply B1 passes through each power supply module 1 (including the coupled inductance element 11, the DC output conversion unit 12, and the capacitor bank 13), the DC input conversion unit 14, and the first power output terminal L1 and the second power supply The output terminal L2 supplies power to the load to maintain the uninterrupted power supply of the load.

As shown in FIG. 5, if the load is an AC load, the usable DC input conversion unit 14 is a DC-to-AC converter (DC-to-AC converter) for receiving the DC power provided by the capacitor bank 13 and converting it The DC power supply is the output of the AC power supply to supply power to the AC load. In this embodiment, the coupling point N of the capacitor bank 13 is coupled to a neutral terminal of the AC load. Each DC input conversion unit 14’ provides an AC live wire output terminal L", and each DC input conversion unit 14’ The over-fired output terminals L" are coupled to each other to achieve output parallel connection. The coupling points N and N'of each power module 1 are coupled to the neutral terminal N"' of the load. The DC input conversion unit 14 of this embodiment can be a traditional half-bridge inverter (Half-Bridge Inverter), but the present invention is not limited by this.

If the AC power supply is normal, the AC power supply supplies power to the load through the DC output conversion unit 12 and the capacitor bank 13, the DC input conversion unit 14', the live output terminal L" and the neutral terminal N"'. If the AC power supply is abnormal, the DC power supply B1 passes through the power supply modules 1 (including the coupled inductance element 11, the DC output conversion unit 12 and the capacitor bank 13), the DC input conversion unit 14', the live output terminal L" and the neutral line The terminal N"' supplies power to the load to maintain the uninterrupted power supply of the load.

In summary, the present invention has the following features and advantages: by using simple circuit elements-coupled inductance elements, such as common mode chokes, it can solve the problem of DC power supply caused by the coupling of the coupling points. The problem of current return between power modules can not only reduce the cost of the circuit, but also simplify the complexity and difficulty of circuit control.

The above are only detailed descriptions and drawings of the preferred specific embodiments of the present invention, but the features of the present invention are not limited thereto, and are not intended to limit the present invention. The full scope of the present invention should be subject to the following patent applications. All embodiments that conform to the spirit of the patent application of the present invention and similar changes should be included in the scope of the present invention. Anyone familiar with the art in the field of the present invention can easily think of changes or modifications. Covered in the following patent scope of this case.

1: Power module

11: Coupling inductance element

12: DC output conversion unit

13: Capacitor bank

B1: DC power supply

C1, C1’: The first capacitor

C2, C2’: second capacitor

D1, D1’: The first diode

D2, D2’: the second diode

D3, D3’: the third diode

D4, D4’: The fourth diode

Q1, Q1’: The first power switch

Q2, Q2’: the second power switch

P1, P1’: Input inductance

N, N’: coupling point

I1, I1’: first current

I2, I2’: second current

IN_1: the first input

OUT_1: the first output terminal

IN_2: second input

OUT_2: second output terminal

Claims (15)

A power converter for a common DC power supply includes: a DC power supply; and at least two power supply modules. The input side of the at least two power supply modules is coupled to the DC power supply; each power supply module is coupled to each other and includes : A coupled inductive element coupled to the DC power supply; a DC output conversion unit coupled to the coupled inductive element; and a capacitor bank coupled to the DC output side of the DC output conversion unit, the capacitor bank having a series connection The two capacitors are coupled with a coupling point between the two capacitors; wherein the output sides of the at least two power modules are coupled to each other through the coupling points. The power converter of the common DC power supply described in the scope of the patent application, wherein the coupled inductance element includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal. The first input terminal and the second output terminal are respectively coupled to the DC power supply, the first output terminal and the second input terminal are respectively coupled to the DC output conversion unit; wherein the first input terminal and the second output terminal have Same polarity; the second input terminal and the first output terminal have the same polarity. According to the power converter of the common DC power supply described in the scope of patent application, each of the first input terminals is coupled to a positive pole of the DC power supply, and each of the second output terminals is coupled to a negative pole of the DC power supply. In the power converter of the common DC power supply described in item 3 of the scope of patent application, the magnitude of the current flowing into the first input terminal is equal to the current flowing out of the second output terminal. In the power converter of the common DC power supply described in the first item of the scope of patent application, the coupled inductance element is a common mode choke coil. According to the power converter of the common DC power supply described in the scope of patent application, each of the DC output conversion units includes: an input inductor; a first diode, a second diode, and the second diode The body and the first diode are coupled to a first common contact point and form a first branch, wherein one end of the input inductor is coupled to the first common contact point; a first power switch, a second Two power switches, the second power switch and the first power switch are coupled to a second common contact and form a second branch, wherein the second branch is coupled in parallel to the first branch; Three diodes are coupled to the first diode and the first power switch; and a fourth diode is coupled to the second diode and the second power switch. The power converter of the common DC power supply described in the scope of patent application, wherein the other end of the input inductor is coupled to the first output end of the coupled inductance element; the second diode and the second power The switch and the fourth diode are coupled to the second input end of the coupled inductance element; the second common contact is coupled to the coupling point; the third diode is coupled to the first power switch and Between the capacitor group; the fourth diode is coupled between the second power switch and the capacitor group. The power converter of the common DC power supply as described in the first item of the scope of patent application, wherein the DC power supply is one of a lithium battery and a lead-acid battery. A power supply device applied to supply power to a load, including: A power converter for a total of DC power sources, such as the power converter for a common DC power source described in any one of items 1 to 8 of the scope of the patent application; and at least two DC input conversion units, each of which has An input terminal and an output terminal, the input terminal is correspondingly coupled to each of the DC output conversion units and each of the capacitor groups, and the output terminal is coupled to the load. For the power supply device described in item 9 of the scope of patent application, each of the DC input conversion units is correspondingly coupled to each of the coupled inductance elements, each of the DC output conversion units and each of the capacitor groups form a power conversion module, and each The power conversion modules are connected in parallel. For the power supply device described in item 9 of the scope of patent application, each of the DC input conversion units is a DC-to-AC converter. The power supply device described in item 11 of the scope of patent application, wherein each of the coupling points is coupled to a neutral terminal of the load. For the power supply device described in item 9 of the scope of patent application, each of the DC input conversion units is a DC-to-DC converter. According to the power supply device described in item 9 of the scope of patent application, each of the DC output conversion units is further coupled to an AC power source; the DC power source or the AC power source is switchably coupled to each of the DC output conversion units, and each of the DC output conversion units is switchably coupled to each of the DC output conversion units. The output conversion unit converts the DC power supply or the AC power supply into a DC output power supply to provide uninterrupted power supply to the load. The power supply device according to claim 14, wherein a first end of the AC power source is coupled between the coupled inductance element and the DC output conversion unit, and a second end of the AC power source is coupled to The coupling point.

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