CN111525814A

CN111525814A - Power supply device based on high-frequency chopping

Info

Publication number: CN111525814A
Application number: CN202010458938.3A
Authority: CN
Inventors: 付莹; 佘猷; 谷涛; 田光兴
Original assignee: CRRC Dalian Co Ltd
Current assignee: CRRC Dalian Co Ltd
Priority date: 2020-05-27
Filing date: 2020-05-27
Publication date: 2020-08-11

Abstract

The invention discloses a power supply device based on high-frequency chopping, which comprises the following components: the first support capacitor is connected with the middle direct current link of the traction branch circuit; the unidirectional inversion unit is connected with the first support capacitor in parallel; the input end of the isolation transformer is respectively connected with the first supporting capacitor and the unidirectional inversion unit; the rectifying unit is connected with the output end of the isolation transformer; and the input end of the chopping unit is connected with the output end of the rectifying unit in parallel, and the output end of the chopping unit is connected with a load. The power supply device based on high-frequency chopping is designed based on high frequency, and by adopting the SIC power device and the high-frequency isolation transformer and simultaneously eliminating the filter inductor in the existing system, the weight of the system can be effectively reduced, the working efficiency of the system is improved, and the power supply device is suitable for application of high-speed and low-axle-weight electric locomotives.

Description

Power supply device based on high-frequency chopping

Technical Field

The invention relates to the field of locomotives, in particular to a power supply device based on high-frequency chopping.

Background

The existing power supply device for the passenger electric locomotives DC600V, such as SS8, SS9, HXD3C, HXD3D, HXD1D and the like, adopts a single-phase half-control rectification technology to rectify single-phase alternating current provided by a traction transformer into a DC600V power supply for passenger trains, and the circuit principle is shown in figure 1. As shown in fig. 1, the circuit is mainly composed of the following components, a1 to x 1: a traction transformer power supply winding; 13KM working contactor; 21R1, 21R2, 31C and 13RV form an overvoltage absorption circuit; v1, V2, V3 and V4 form a single-phase half-controlled rectifying circuit, wherein V1 and V2 are diodes, and V3 and V4 are thyristors; a filter loop is formed by the 13L filter inductor and the 19C filter capacitor; the power supply connector KC 20D.

The specific working principle is as follows: the traction transformer power supply windings a 1-x 1 reduce the high voltage of the single-phase AC25kV received by the pantograph of the electric locomotive into single-phase AC870V, and supply the single-phase AC870 to a single-phase half-controlled rectifying circuit consisting of V1, V2, V3 and V4 through the working contactor 13KM and an overvoltage absorption circuit. The single-phase half-controlled rectifying circuit is used for rectifying a single-phase AC870V power supply into DC600V, and outputting the DC600V through a filter inductor (13L), a filter capacitor (19C) and a power supply connector KC 20D.

The prior art has the following defects:

1. the traction transformer needs to be provided with a power supply winding independently, so that the design structure of the transformer is complex, and the size and the weight of the transformer are overlarge;

2. the influence of the voltage of a contact network is large, the harmonic content of an input power supply is high, the fault of an overvoltage absorption circuit is easily caused, and the reliability of a power supply device is low; the input power supply fluctuates between 17.5 and 31.5kV, the output fluctuation of the power supply device is large, the output voltage fluctuates between DC500V and DC700V, and the damage of an inverter and charger equipment on a passenger car is easily caused;

3. the single-phase half-controlled rectifying circuit is adopted, the electric elements use diodes and thyristors, the system modulation frequency is low, the power loss is large, the harmonic content of the output DC600V power supply is high, the efficiency of the power supply device can only reach about 0.9, and the power factor is between 0.7 and 0.9;

4. in order to control the index that the peak-to-peak ripple factor of the output voltage is not more than 15%, a power supply device needs to be provided with a large-capacity filter inductor 13L (13mH), the self weight of the filter inductor is about 800kg, the light weight design of a system is not facilitated, and meanwhile, the manufacturing cost is increased;

5. the traction transformer is adopted to supply power through the power supply winding, and when the locomotive passes through the phase-splitting area, the power supply device cannot work, so that the power supply of a carriage of the passenger car is interrupted, and the riding comfort of passengers is poor.

Disclosure of Invention

In view of this, an object of the embodiments of the present invention is to provide a power supply device based on high-frequency chopping, which can effectively reduce the weight of a system by using a high-frequency isolation transformer and eliminating a filter inductor in an existing system, and is suitable for application to an electric locomotive with a high speed and a low axle load.

In view of the above object, an aspect of the embodiments of the present invention provides a power supply device based on high-frequency chopping, including the following components:

the first support capacitor is connected with the middle direct current link of the traction branch circuit;

the unidirectional inversion unit is connected with the first support capacitor in parallel;

the input end of the isolation transformer is respectively connected with the first supporting capacitor and the unidirectional inversion unit;

the rectifying unit is connected with the output end of the isolation transformer; and

and the input end of the chopping unit is connected with the output end of the rectifying unit in parallel, and the output end of the chopping unit is connected with a load.

In some embodiments, the first support capacitor comprises a plurality of series-connected sub-support capacitors that are symmetric about a connection point of the first support capacitor to the isolated inverter.

In some embodiments, the unidirectional inversion unit includes two power units connected in series, the two power units being symmetrical about a connection point of the unidirectional inversion unit and the isolation inverter.

In some embodiments, the power unit comprises:

a silicon carbide element;

a diode connected in parallel with the silicon carbide element.

In some embodiments, the silicon carbide element comprises a plurality of MOS transistors connected in parallel or in series.

In some embodiments, the rectifying unit includes a plurality of diodes, which constitute a rectifying bridge.

In some embodiments, the rectifier unit includes four diodes, and the two output ends of the isolation transformer are connected to the middle points of the two legs of the rectifier bridge.

In some embodiments, the chopper unit includes a silicon carbide MOS transistor and a diode, one end of the silicon carbide MOS transistor connected to the diode is connected to one end of the output terminal of the rectifier unit, and the other end of the silicon carbide MOS transistor is connected to the other end of the output terminal of the rectifier unit.

In some embodiments, further comprising:

a second support capacitor connected in parallel with an input of the chopping unit.

In some embodiments, further comprising:

and the filter capacitor is connected with the output end of the chopping unit in parallel.

The invention has the following beneficial technical effects:

1. according to the technical scheme, the direct current loop in the middle of the traction branch is adopted for supplying power, and the traction transformer is not provided with a power supply winding independently, so that the design of the traction transformer can be simplified, the weight and the volume of the traction transformer are reduced, and the manufacturing cost is reduced;

2. according to the technical scheme, SIC (silicon carbide) devices are adopted in a single-phase inversion unit and a chopping unit, and the SIC has the characteristics of high switching frequency and switching loss, so that the system can obtain higher working efficiency and power factor, and is more energy-saving and environment-friendly;

3. the technical scheme of the invention has high system working frequency, can adopt a high-frequency isolation transformer, simultaneously cancels the filter inductance of the existing system, can effectively reduce the weight of the system, and is suitable for the application of high-speed and low-axle-weight electric locomotives;

4. according to the technical scheme, the power input is not directly related to the voltage of the contact network, the traction transformer is not relied on, the voltage fluctuation and the higher harmonic influence of the contact network can be effectively reduced, and the reliability of the DC600V power supply device is improved; meanwhile, when the locomotive passes through a split-phase area, the uninterrupted power supply function of a train power supply system can be realized, and the riding comfort of passengers is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other embodiments can be obtained by using the drawings without creative efforts.

FIG. 1 is a schematic circuit diagram of a prior art locomotive power supply;

FIG. 2 is a schematic diagram of a prior art pulling leg;

fig. 3 is a schematic circuit diagram of an embodiment of the power supply device based on high-frequency chopping according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the following embodiments of the present invention are described in further detail with reference to the accompanying drawings.

It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are used for distinguishing two entities with the same name but different names or different parameters, and it should be noted that "first" and "second" are merely for convenience of description and should not be construed as limitations of the embodiments of the present invention, and they are not described in any more detail in the following embodiments.

In view of the above object, a first aspect of an embodiment of the present invention provides a power supply device based on high-frequency chopping.

At present, the domestic passenger train adopts a centralized power supply mode, a DC600V power supply device is independently arranged on a locomotive and is transmitted to a passenger train compartment through a train power supply bus. The passenger train carriage is provided with inverter, provides three-phase 380V power to carriage consumer after with DC600V voltage contravariant to satisfy the power consumption demand of equipment such as passenger train air conditioner, electric heater. The DC600V power supply device on the locomotive is the key of the whole passenger train power supply system, and the quality of the DC600V power supply device directly influences whether the whole power supply system can work normally or not. Prior art ac powered electric locomotives typically have separate traction legs and DC600V power supplies. Fig. 2 shows a schematic diagram of a prior art traction branch. As shown in fig. 2, the traction branch is mainly composed of a traction transformer traction winding 11, a four-quadrant rectifier 12, an intermediate dc link 13, a traction inverter 14 and a traction motor 15.

Fig. 3 is a schematic circuit diagram of an embodiment of the power supply device based on high-frequency chopping according to the present invention. As shown in fig. 3, the power supply device includes:

the first supporting capacitor 1 is connected with the middle direct current link 13 of the traction branch circuit 1;

the unidirectional inversion unit 2 is connected with the first support capacitor 1 in parallel;

the input end of the isolation transformer T is respectively connected with the first supporting capacitor 1 and the unidirectional inversion unit 2;

the rectifying unit 3 is connected with the output end of the isolation transformer T; and

and the input end of the chopping unit 4 is connected with the output end of the rectifying unit 3 in parallel, and the output end of the chopping unit 4 is connected with a load.

In fig. 3, one end of a-B is connected with the intermediate direct current link 13 of the traction branch, and the other end is connected with the first supporting capacitor 1. In some embodiments, the first support capacitor 1 comprises a plurality of series-connected sub-support capacitors that are symmetrical about a connection point of the first support capacitor 1 with the isolated inverter T. The isolation transformer T may be a high-frequency single-phase transformer. The first supporting capacitor 1 may comprise a plurality of sub-supporting capacitors connected in series, and only two sub-supporting capacitors C1 and C2 are shown in fig. 3, but this is merely exemplary, and four, six or another number of sub-supporting capacitors may be used in other embodiments. The sub-support capacitors may be symmetrical with respect to a connection point of the first support capacitor 1 and the isolation inverter T, and the plurality of sub-support capacitors of the first support capacitor may be divided into an upper portion and a lower portion according to the connection point of the first support capacitor 1 and the isolation inverter T, where "symmetrical" includes not only that the sub-support capacitors of the upper portion and the lower portion are arranged exactly the same, but also that the number of the sub-support capacitors of the upper portion and the lower portion is the same. That is, as long as the number of the sub-supporting capacitors of the upper half part and the lower half part is the same, the arrangement of the sub-supporting capacitors is within the protection range of the above-mentioned "symmetry" regardless of symmetry.

In some embodiments, the unidirectional inversion unit 2 includes two power units S1 and S2 connected in series, the two power units S1 and S2 being symmetrical about a connection point of the unidirectional inversion unit 2 and the isolated inverter T. For convenience of description, the end of the two power cells S1 and S2 connected to each other is referred to as a common end, and the "symmetry" is used herein to emphasize that the isolated inverter is connected to the common end of the two power cells, and does not require that the power cells S1 and S2 be strictly symmetrical about the connection point.

In some embodiments, the power unit comprises: a silicon carbide element; a diode connected in parallel with the silicon carbide element. The silicon carbide element has the characteristics of high switching frequency and small switching loss. In some embodiments, the silicon carbide element includes a plurality of MOS (metal oxide semiconductor) transistors, and the plurality of MOS transistors are connected in parallel or in series. Furthermore, when all the MOS transistors in S1 are connected in parallel and all the MOS transistors in S2 are connected in series, the protection range of the above "symmetry" also belongs.

In some embodiments, the rectifying unit includes a plurality of diodes, which constitute a rectifying bridge. In some embodiments, the rectifier unit includes four diodes, and the two output ends of the isolation transformer are connected to the middle points of the two legs of the rectifier bridge. For example, fig. 3 includes four diodes D1, D2, D3 and D4, which form a rectifier bridge, and two output terminals of the isolation transformer T are respectively connected to the middle points of two legs of the rectifier bridge, where the "middle point" emphasizes that the output terminals of the transformer are connected to the legs, even if the connection point of D1 and D2 in fig. 3 is not at the middle point of D1 and D2, as long as the connection point is between D1 and D2, which falls within the protection scope of the present application.

In some embodiments, the chopper unit 4 includes a MOS transistor and a diode, one end of the MOS transistor connected to the diode is connected to one end of the output terminal of the rectifier unit 3, and the other end of the MOS transistor is connected to the other end of the output terminal of the rectifier unit 3.

In some embodiments, further comprising: a second supporting capacitor C3, the second supporting capacitor C3 being connected in parallel with the input of the chopping unit 4. The second supporting capacitor C3 is used to stabilize the output voltage of the rectifying unit 3 and isolate the higher harmonics in the output voltage.

In some embodiments, further comprising: a filter capacitor C4, wherein the filter capacitor C4 is connected with the output end of the chopper unit 4 in parallel. The filter capacitor C4 is used to isolate higher harmonics in the DC600V output voltage.

Electric energy is input into the first supporting capacitor 1 from the middle direct current link 13 of the traction branch circuit through a path A-B, and the first supporting capacitor 1 plays a role in stabilizing input voltage; the single-phase inversion unit 2 inverts the voltage of the middle direct-current link of the traction branch stabilized by the first supporting capacitor 1 into a high-frequency alternating-current voltage; the isolation transformer T converts the voltage level of the high-frequency alternating voltage output by the single-phase inversion unit 2 and provides the high-frequency alternating voltage to the rectification unit 3; the rectifying unit 3 rectifies the high-frequency alternating-current voltage converted by the isolation transformer T into direct-current voltage; the chopper unit 4 chops the direct-current voltage stabilized by the second supporting capacitor C3 at a high frequency, filters the direct-current voltage by the filter capacitor C4, and supplies electric energy to the DC600V load through C-D.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as software or hardware depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosed embodiments of the present invention.

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with the following components designed to perform the functions herein: a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these components. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP, and/or any other such configuration.

The steps of a method or algorithm described in connection with the disclosure herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary designs, the functions may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk, blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The foregoing is an exemplary embodiment of the present disclosure, but it should be noted that various changes and modifications could be made herein without departing from the scope of the present disclosure as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the disclosed embodiments described herein need not be performed in any particular order. Furthermore, although elements of the disclosed embodiments of the invention may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

It should be understood that, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly supports the exception. It should also be understood that "and/or" as used herein is meant to include any and all possible combinations of one or more of the associated listed items.

The numbers of the embodiments disclosed in the embodiments of the present invention are merely for description, and do not represent the merits of the embodiments.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, of embodiments of the invention is limited to these examples; within the idea of an embodiment of the invention, also technical features in the above embodiment or in different embodiments may be combined and there are many other variations of the different aspects of the embodiments of the invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, substitutions, improvements, and the like that may be made without departing from the spirit and principles of the embodiments of the present invention are intended to be included within the scope of the embodiments of the present invention.

Claims

1. A power supply device based on high-frequency chopping, comprising:

2. The power supply device according to claim 1, wherein the first support capacitor comprises a plurality of series-connected sub-support capacitors, the plurality of sub-support capacitors being symmetrical about a connection point of the first support capacitor to the isolated inverter.

3. The power supply device according to claim 2, wherein the unidirectional inversion unit includes two power units connected in series, and the two power units are symmetrical with respect to a connection point of the unidirectional inversion unit and the isolation inverter.

4. The power supply device according to claim 3, wherein the power unit includes:

a silicon carbide element;

a diode connected in parallel with the silicon carbide element.

5. The power supply device according to claim 4, wherein the silicon carbide element comprises a plurality of MOS transistors connected in parallel or in series.

6. The power supply device according to claim 1, wherein the rectifying unit includes a plurality of diodes, and the plurality of diodes constitute a rectifying bridge.

7. The power supply device according to claim 6, wherein the rectifying unit comprises four diodes, and two output ends of the isolation transformer are connected with the middle points of two bridge arms of the rectifying bridge.

8. The power supply device according to claim 1, wherein the chopper unit includes a silicon carbide MOS transistor and a diode, one end of the silicon carbide MOS transistor connected to the diode is connected to one end of the output terminal of the rectifier unit, and the other end of the silicon carbide MOS transistor is connected to the other end of the output terminal of the rectifier unit.

9. The power supply device according to claim 1, further comprising:

10. The power supply device according to claim 1, further comprising: