WO2019113922A1 - Power conversion unit, auxiliary locomotive power supply current conversion circuit, and locomotive - Google Patents

Abstract

Provided are a power conversion unit (10), an auxiliary locomotive power supply current conversion circuit, and a locomotive. The power conversion unit (10) comprises: at least three groups of power conversion sub-units (13), a support capacitor group (11) and a protection circuit (12), wherein the at least three groups of power conversion sub-units (13) are used for converting a direct current into a three-phase alternating current, and comprise double-tube IGBTs (131) and drive circuits (DBR, DBS, DBT). The double-tube IGBTs (131) have high junction temperatures, and two input ends of the double-tube IGBTs (131) are respectively connected to an external positive and negative two-layer laminated busbar (DC+, DC-), and three output ends of the double-tube IGBTs (131) are respectively connected to an RST three-phase output laminated busbar. The drive circuits (DBR, DBS, DBT) are connected to a control unit, and the drive circuits (DBR, DBS, DBT) are used for controlling the switching on and switching off of the double-tube IGBTs (131). The support capacitor group (11) is applicable to a high-temperature environment and is used for supporting a direct-current circuit voltage. The protection circuit (12) is used for protecting the other components in the power conversion unit (10). The double-tube IGBTs (131), the support capacitor group (11) and the protection circuit (12) are connected to each other in parallel. According to the power conversion unit (10), the service life of the power conversion unit (10) in a high-temperature environment can be prolonged.

Description

Power conversion unit, locomotive auxiliary power supply converter circuit and locomotive Technical field

The invention relates to locomotive technology, in particular to a power conversion unit, a locomotive auxiliary power supply converter circuit and a locomotive.

Background technique

With the development of locomotive technology, converters using Insulated Gate Bipolar Transistors (IGBTs) as switching elements are increasingly used. In order to facilitate the maintenance of the main circuit, a plurality of IGBTs of the main circuit are usually integrated and installed to form a power conversion unit.

In practical applications, the power conversion unit is the core component of the locomotive auxiliary power supply converter circuit. Specifically, the output DC power of the intermediate DC loop of the locomotive is converted into three-phase alternating current by a three-phase circuit composed of IGBTs on the power conversion unit to supply power to the auxiliary electric equipment of the locomotive.

However, the existing power conversion unit is only suitable for low temperature environments, such as below 50 ° C, low service life in high temperature 70 ° C environment, poor operational reliability, and high maintenance costs. Therefore, there is a need for a power conversion unit suitable for use in a high temperature environment.

Summary of the invention

The invention provides a power conversion unit, a locomotive auxiliary power supply converter circuit and a locomotive to prolong the service life of the power conversion unit in a high temperature environment.

In a first aspect, the present invention provides a power conversion unit. The power conversion unit includes: at least three sets of power conversion subunits, a supporting capacitor group suitable for a high temperature environment, and a protection circuit; specifically,

The at least three sets of power conversion subunits for converting direct current into three-phase alternating current; the power conversion subunit includes: a dual tube IGBT and a driving circuit, wherein the dual tube IGBT has a high junction temperature, the double The two input ends of the tube IGBT are respectively connected to the external positive and negative two-layer busbars, and the three output ends of the double-tube IGBT are respectively connected with the RST three-phase output laminated busbar; the driving circuit is connected with the control unit, The driving circuit is configured to control the double tube IGBT switch;

The supporting capacitor group is configured to support a DC link voltage;

The protection circuit is configured to protect other components in the power conversion unit;

The dual tube IGBT, the supporting capacitor group and the protection circuit are connected in parallel with each other.

In a possible design manner, the power conversion subunit further includes: an absorption capacitor;

The absorption capacitor is connected in parallel with the double-tube IGBT, and the absorption capacitor is used to absorb an overvoltage generated when the double-tube IGBT is turned off.

In a possible design manner, the supporting capacitor group includes at least one cylindrical film capacitor, and the cylindrical film capacitor is suitable for a high temperature environment;

When the number of the cylindrical film capacitors is at least two, the at least two cylindrical film capacitors are connected in parallel to each other to reach a capacitance value required by the power conversion unit.

In a possible design, the protection circuit comprises two resistors connected in parallel with each other.

In a possible design, the driving circuit is further configured to: feed back the switching state of the dual-tube IGBT to the control unit.

In a possible design manner, the power conversion unit further includes: a heat sink, and the double tube IGBT is mounted on a surface of the heat sink.

In a possible design manner, the power conversion unit further includes: a temperature detecting switch, when the temperature of the heat sink is greater than or equal to a set value, the state of the temperature detecting switch changes, and is used to indicate A switching signal of a state change of the temperature detecting switch is transmitted to the control unit.

In a possible design manner, the power conversion unit further includes: a frame;

The frame is mounted on a surface of the heat sink;

The double tube IGBT is located inside the frame;

The outer positive and negative two-layer busbars are installed between the left and right frame walls in the frame;

The supporting capacitor group is installed in the frame through a support plate at a position between the rear frame wall and the outer positive and negative two-layer busbars;

The drive circuit is mounted to a front frame wall of the frame.

In a second aspect, the present invention provides a locomotive auxiliary power supply converter circuit, the locomotive auxiliary power supply converter circuit comprising the power conversion unit of the first aspect.

In a third aspect, the present invention provides a locomotive comprising the power conversion unit of the first aspect.

The power conversion unit, the locomotive auxiliary power supply converter circuit and the locomotive provided by the invention convert the direct current into three-phase alternating current through at least three sets of power conversion subunits, wherein the power conversion subunit comprises a double tube IGBT and a driving circuit, the double tube The two input ends of the IGBT are respectively connected to the external positive and negative two-layer busbars, and the three output ends of the double-tube IGBT are respectively connected with the RST three-phase output laminated busbar; the driving circuit is connected with the control unit, and the driving circuit is used for In order to control the switch of the double-tube IGBT; in addition, the DC link voltage is supported by the support capacitor group to ensure that the fluctuation of the DC link voltage is within the required range; and other components in the power conversion unit are protected by the protection circuit. Since the double-tube IGBT has a high junction temperature, and the supporting capacitor group is suitable for a high temperature environment and has a long life, the power conversion unit can be used for a long time in a high temperature environment. Therefore, compared with the existing power conversion unit, the power conversion unit provided by the invention can extend the service life of the power conversion unit in a high temperature environment, improve the reliability of the power conversion unit, and reduce the maintenance cost.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description of the drawings used in the embodiments or the prior art description will be briefly described below. Obviously, the drawings in the following description It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any inventive labor.

1 is a schematic structural diagram of a circuit of a power conversion unit according to Embodiment 1 of the present invention;

2 is a schematic view showing the external structure of a cylindrical film capacitor according to the present invention;

3 is a front perspective view showing the power conversion unit of FIG. 1;

4 is a schematic perspective view showing the back side of the power conversion unit shown in FIG. 1;

5 is a front perspective structural view of a second embodiment of a power conversion unit according to the present invention;

FIG. 6 is a schematic diagram of a back side three-dimensional structure of a second embodiment of a power conversion unit according to the present invention.

Description of the reference signs:

10: power conversion unit;

11: supporting capacitor group;

12: protection circuit;

13: power conversion subunit;

131: double tube IGBT;

132: RST three-phase output laminated mother;

14: radiator;

21: bolt;

22: aluminum casing;

23: plastic insulation sleeve;

24: plastic insulated boss;

25: copper nut;

26: black epoxy resin;

51: framework;

52: support plate;

53: support frame;

DBR, DBR and DBT: drive circuit;

DC+ and DC-: external positive and negative two-layer busbars;

C1, C2 and C3: absorption capacitance;

C4, C5, C6, C7, C8, C9, C10 and C11: cylindrical film capacitors;

R1 and R2: resistance;

T1: Temperature detection switch.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. It is a partial embodiment of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

The terms "comprises" and "comprising", and any variations thereof, are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or The apparatus is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not explicitly listed or inherent to such procedures, methods, products, or devices.

The existing power conversion unit is generally only applicable to an ambient temperature below +50 ° C. When the ambient temperature is greater than +50 ° C, the existing power conversion unit is easily damaged. Therefore, the object of the present invention is to make the power conversion unit suitable for a high temperature environment. For example, +70 ° C environment.

First, some of the technical terms in the present invention are explained below so as to be understood by those skilled in the art:

Junction temperature is one of the important parameters of IGBT, usually including Tjmax and Tjop, that is, continuous, stable load junction temperature (steady-state junction temperature) does not exceed Tjop; transient, transition process junction temperature (transient junction temperature) ) does not exceed Tjmax.

The laminated busbar, also known as the composite busbar, the laminated busbar, the laminated busbar row or the composite copper row, is a multi-layer composite structure connecting row, which can be regarded as a highway of a power distribution system. The use of laminated busbars provides a modern, easy to design, fast to install and clearly structured power distribution system compared to conventional wiring methods. The laminated busbar is a high-power modular connecting structural component with reproducible electrical performance, low impedance, anti-interference, high reliability, space saving, and simple and quick assembly. Laminated busbars are widely used in power and hybrid traction, electric traction equipment, cellular communications, base stations, telephone switching systems, large network equipment, large and medium-sized computers, power switching systems, welding systems, military equipment systems, power generation systems, and electric equipment. Power conversion module, etc.

The temperature relay is a method in which two metals or alloys with widely different thermal expansion coefficients are firmly combined with each other to form a disc-shaped bimetal. When the temperature rises to a certain value, the bimetal will expand due to the expansion of the lower metal, and the upper layer The expansion of the metal is small and the force of upward bending is generated. When the bending is performed to a certain extent, the electrical contact can be driven to realize the function of turning on or off the load circuit; when the temperature is lowered to a certain value, the bimetal is gradually restored to the original state and restored to a certain degree. To the extent, the electrical contacts are driven in reverse to achieve the function of disconnecting or switching on the load circuit.

Multiple, including two or more.

Next, the specific structure of the power conversion unit provided by the present invention will be explained based on the above problems and technical terms.

FIG. 1 is a schematic structural diagram of a circuit of a first embodiment of a power conversion unit according to the present invention. As shown in FIG. 1, the power conversion unit 10 includes a support capacitor group 11, a protection circuit 12, and a power conversion sub-unit 13, wherein the number of power conversion sub-units 13 is three. specifically,

Support capacitor group 11, suitable for high temperature environment, used to support DC link voltage.

The protection circuit 12 is for protecting other components in the power conversion unit 10, for example, the power conversion sub-unit 13 and the like.

The three sets of power conversion subunits 13 are for converting direct current into three-phase alternating current. The power conversion subunit 13 includes a double tube IGBT 131 and a drive circuit DBR (or a drive circuit DBR or a drive circuit DBT). The connection relationship between the double-tube IGBT and the driving circuit can be exemplified in FIG. 1 , and details are not described herein again.

Among them, the double-tube IGBT 131 has a high junction temperature, for example, a junction temperature of 150 °C. Among the two input ends of the double-tube IGBT 131, one input terminal is connected to the external positive and negative two-layer busbar DC+, and the other input terminal is connected to the external positive and negative two-layer busbar DC-connection. The three output terminals of the double-tube IGBT 131 are respectively connected to the RST three-phase output laminated bus. That is, R, S, and T are three-phase AC outputs of the power conversion unit 10.

In the circuit shown in FIG. 1, the external positive and negative two-layer busbar DC+ and the external positive and negative two-layer busbar DC- are the two input ends of the power conversion unit 10, and the direct current is input through the two input terminals through three The double-tube IGBT 131 is connected with the RST three-phase output laminated busbar to form a standard three-phase inverter main circuit, which realizes power conversion from direct current to three-phase alternating current.

The drive circuit DBR, the drive circuit DBS, and the drive circuit DBT are all connected to a control unit (not shown); the drive circuit DBR, the drive circuit DBS, and the drive circuit DBT are both used to control the switches of the corresponding double-tube IGBTs 131.

Each driving circuit provides two driving signals to drive two IGBT units of one inverter bridge arm. The two-tube IGBT includes two IGBT units and two diodes, and the diode has a high junction temperature, and the specific connection relationship is as follows. As shown in Figure 1, it will not be described here. It can be understood that when the driving circuit and the double-tube IGBT are included in the same power conversion sub-unit, the driving circuit controls the switching of the double-tube IGBT. Optionally, the driving circuit is further configured to: feed back the switching state of the dual-tube IGBT to the control unit.

Further, the double-tube IGBT 131, the supporting capacitor group 11, and the protection circuit 12 are connected in parallel to each other.

It should be noted that FIG. 1 illustrates three sets of power conversion subunits 13 as an example, but the present invention is not limited thereto. That is to say, the number of power conversion subunits may be three or more groups, as long as the at least three sets of power conversion subunits can realize the function of converting direct current into three-phase alternating current.

In this embodiment, the direct current is converted into three-phase alternating current by at least three sets of power conversion subunits, wherein the power conversion subunit comprises a double tube IGBT and a driving circuit, and the two input ends of the double tube IGBT are respectively stacked with the external positive and negative The busbars are connected, and the three output ends of the dual-tube IGBT are respectively connected with the RST three-phase output laminated busbar; the driving circuit is connected with the control unit, and the driving circuit is used for controlling the switch of the double-tube IGBT; The capacitor group supports the DC link voltage to ensure that the fluctuation of the DC link voltage is within the required range; the other components in the power conversion unit are protected by the protection circuit. Since the double-tube IGBT has a high junction temperature, and the supporting capacitor group is suitable for a high temperature environment and has a long life, the power conversion unit can be used for a long time in a high temperature environment. Therefore, compared with the existing power conversion unit, the power conversion unit provided by the invention can extend the service life of the power conversion unit in a high temperature environment, improve the reliability of the power conversion unit, and reduce the maintenance cost.

Based on the above, still referring to FIG. 1, the power conversion subunit 13 further includes: an absorption capacitor C1 (or an absorption capacitor C2, or an absorption capacitor C3). Wherein, in the same power conversion subunit 13, the absorption capacitor is connected in parallel with the double-tube IGBT 131, and the absorption capacitor is used to absorb the overvoltage generated when the double-tube IGBT 131 is turned off.

Alternatively, the supporting capacitor group 11 may include at least one cylindrical film capacitor. The cylindrical film capacitor is suitable for use in high temperature environments.

2 is a schematic view showing the external structure of a cylindrical film capacitor according to the present invention. As shown in FIG. 2, the bottom of the cylindrical film capacitor 20 has a bolt 21, which is used with a nut for vertical installation; the outer side of the cylindrical film capacitor 20 is covered with an aluminum outer casing 22, and the outer upper portion is provided with a plastic insulating sleeve 23 The top of the cylindrical film capacitor 20 includes two plastic insulating bosses 24, and the plastic insulating boss 24 is provided with a copper nut 25 for electrically connecting with the external positive and negative two-layer busbars through the stud bolts. The shell of the cylindrical film capacitor 20 is filled with an insulating black epoxy resin 26.

When the number of cylindrical film capacitors is at least two, the at least two cylindrical film capacitors are connected in parallel to each other to reach a capacitance value required by the power conversion unit 10.

Taking FIG. 1 as an example, the supporting capacitor group 11 includes eight cylindrical film capacitors: a cylindrical film capacitor C4 to a cylindrical film capacitor C11. The eight cylindrical film capacitors are connected in parallel to form a supporting capacitor group 11 for supporting the DC link voltage to ensure that the fluctuation of the DC link voltage is within the required range.

In order to solve the problem that the electrolytic capacitor has a sharp decline in the service life from 50 ° C to 70 ° C, the electrolyte is leaked after a long period of use, the repair and replacement cycle is short, and the maintenance cost is high, the present invention designs a new cylindrical film capacitor according to a high temperature environment, the unit The cylindrical film capacitor with the largest capacitance value is optimized in the volume. In a limited space, 8 cylindrical film capacitors are used in parallel to reach the capacitance value required by the power conversion unit 10, which can solve the problem of using the electrolytic capacitor to have a low life under high temperature conditions. The problem of liquid leakage can solve the problem of heat dissipation of rectangular film capacitors. In the high temperature environment of 70 °C, the life of a typical electrolytic capacitor is only about 15,000 hours, and the life of a newly designed cylindrical film capacitor suitable for high temperature environment is 50000. More than an hour.

In a possible implementation, the protection circuit 12 includes two resistors connected in parallel with each other. As shown in Figure 1, the resistor R1 and the resistor R2 are the discharge resistors of the DC loop. After the main circuit is powered off, the residual voltage on the DC loop capacitor drops below the safe voltage within the required time.

Further, the power conversion unit 10 further includes a heat sink (not shown in FIG. 1). Among them, the double-tube IGBT 131 is mounted on the surface of the heat sink.

Since the heat sink can quickly transfer the heat generated by the double-tube IGBT to other parts and dissipate heat uniformly, the substrate temperature of the double-tube IGBT 131 can be effectively reduced, and the function of protecting the double-tube IGBT can be exerted.

Further, the power conversion unit 10 further includes: a temperature detecting switch T1. When the temperature of the heat sink is greater than or equal to the set value, the state of the temperature detecting switch T1 changes, and a switching signal for indicating a state change of the temperature detecting switch T1 is transmitted to the control unit. The state change of the temperature detecting switch T1 includes the temperature detecting switch T1 being changed from being closed to being closed, and the temperature detecting switch T1 being changed from being turned off to being closed, and the setting may be set according to actual requirements, which is not limited in the embodiment of the present invention. In the specific implementation, the temperature detecting switch T1 is a temperature relay of 105 ° C to 90 ° C which can be selected according to a high temperature environment.

Illustratively, FIG. 3 is a schematic front perspective view of the power conversion unit shown in FIG. 1. 4 is a schematic perspective view showing the back side of the power conversion unit shown in FIG. 1. In the power conversion unit 30, the RST three-phase output stack busbar is identified as 132 and the heat sink designation is 14.

The power conversion unit has the functions of intermediate DC voltage support, shutdown overvoltage absorption, double tube IGBT driving and protection, and heat dissipation in a high temperature environment, and finally inverts the input DC power into a three-phase AC output.

FIG. 5 is a schematic front structural view of a second embodiment of a power conversion unit according to the present invention. FIG. 6 is a schematic diagram of a back side three-dimensional structure of a second embodiment of a power conversion unit according to the present invention. In FIGS. 5 and 6, the power conversion unit 50 further includes a frame 51.

In this embodiment, the frame 51 is mounted on the surface of the heat sink 14; the double-tube IGBT (not shown) is located inside the frame 51; the outer positive and negative two-layer busbars (DC+ and DC-) are mounted in the left and right frames of the frame 51. Between the walls; a supporting capacitor group (not shown) is mounted in the frame 51 through the support plate 52, at a position between the rear frame wall and the outer positive and negative two-layer busbars (DC+ and DC-); the drive circuit DBR ( And, the drive circuit DBS and the drive circuit DBT) are mounted on the front frame wall of the frame 51.

In addition, a fast pin connection is used between the driving circuit and the double-tube IGBT, and the driving circuit and the control unit outside the power conversion unit are connected by a connector. The power conversion unit is connected to the external power, and the power terminal can be electrically connected; the power conversion unit is externally mechanically connected, and four long screws and a front end fixed support frame 53 can be fixedly connected with the mounting board.

The bottom of the external positive and negative two-layer busbar 6 L-shaped pins are directly fixed on the three double-tube IGBTs by M8 bolts, and eight cylindrical film capacitors and three absorption capacitors are mounted on the vertical surface, and eight cylindrical films are mounted. The capacitors are arranged in parallel in two rows, supported by the two support plates 52 in front and rear, and then fixed on the frame 51 to form a supporting capacitor group with high life, high capacitance and high reliability.

On the basis of the above embodiments, the present invention further provides a locomotive auxiliary power supply converter circuit, the locomotive auxiliary power supply converter circuit comprising the power conversion unit according to any of the above embodiments.

Further, the present invention provides a locomotive comprising the power conversion unit according to any of the above embodiments.

Since the power conversion unit provided by the embodiment of the invention is suitable for a high temperature environment, the service life of the power conversion unit in a high temperature environment can be prolonged, thereby solving the problem that the power conversion unit is easily damaged in a high temperature environment and affecting the normal operation of the locomotive, and reducing the locomotive. Operating costs and maintenance costs.

In summary, the present invention has at least the following beneficial effects:

Suitable for high temperature environments;

The circuit layout is simple and the cost is low;

Solve the problem that the electrolytic capacitor has a low service life in a high temperature environment;

Achieving a reasonable maintenance cycle in a high temperature environment can effectively reduce the locomotive operating costs and maintenance costs.

In the several embodiments provided by the present invention, it should be understood that the disclosed apparatus may be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the unit or module is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or modules may be used. Combinations can be integrated into another system, or some features can be ignored or not executed. Alternatively, the connections shown or discussed to one another may be electrical, mechanical or other forms.

Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Claims (10)

1. A power conversion unit, comprising: at least three sets of power conversion subunits, a supporting capacitor group and a protection circuit suitable for a high temperature environment; wherein

   The at least three sets of power conversion subunits are configured to convert direct current into three-phase alternating current; the power conversion subunit includes: a double-tube insulated gate bipolar transistor IGBT and a driving circuit, wherein the dual-tube IGBT has a high a junction temperature, the two input ends of the double-tube IGBT are respectively connected to the external positive and negative two-layer busbar, and the three output ends of the double-tube IGBT are respectively connected with the RST three-phase output laminated busbar; The circuit is connected to the control unit, and the driving circuit is configured to control the switch of the double-tube IGBT;

   The supporting capacitor group is configured to support a DC link voltage;

   The protection circuit is configured to protect other components in the power conversion unit;

   The dual tube IGBT, the supporting capacitor group and the protection circuit are connected in parallel with each other.
2. The power conversion unit according to claim 1, wherein the power conversion subunit further comprises: an absorption capacitor;

   The absorption capacitor is connected in parallel with the double-tube IGBT, and the absorption capacitor is used to absorb an overvoltage generated when the double-tube IGBT is turned off.
3. The power conversion unit according to claim 1, wherein said supporting capacitor group comprises at least one cylindrical film capacitor, said cylindrical film capacitor being suitable for use in a high temperature environment;

   When the number of the cylindrical film capacitors is at least two, the at least two cylindrical film capacitors are connected in parallel to each other to reach a capacitance value required by the power conversion unit.
4. The power conversion unit according to claim 1, wherein said protection circuit comprises two resistors connected in parallel with each other.
5. The power conversion unit according to claim 1, wherein the driving circuit is further configured to: feed back a switching state of the dual-tube IGBT to the control unit.
6. The power conversion unit according to any one of claims 1 to 5, further comprising:

   A heat sink, the double tube IGBT being mounted on a surface of the heat sink.
7. The power conversion unit according to claim 6, further comprising:

   a temperature detecting switch, when the temperature of the heat sink is greater than or equal to a set value, the temperature The state of the switch is detected to change, and a switch signal for indicating a change in state of the temperature detecting switch is transmitted to the control unit.
8. The power conversion unit according to claim 6, further comprising: a frame;

   The frame is mounted on a surface of the heat sink;

   The double tube IGBT is located inside the frame;

   The outer positive and negative two-layer busbars are installed between the left and right frame walls in the frame;

   The supporting capacitor group is installed in the frame through a support plate at a position between the rear frame wall and the outer positive and negative two-layer busbars;

   The drive circuit is mounted to a front frame wall of the frame.
9. A locomotive auxiliary power supply converter circuit, comprising the power conversion unit according to any one of claims 1 to 8.
10. A locomotive characterized by comprising the locomotive auxiliary power supply converter circuit of claim 9.

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