CN108768195B - Power circuit, power module and converter - Google Patents

Power circuit, power module and converter Download PDF

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Publication number
CN108768195B
CN108768195B CN201810696727.6A CN201810696727A CN108768195B CN 108768195 B CN108768195 B CN 108768195B CN 201810696727 A CN201810696727 A CN 201810696727A CN 108768195 B CN108768195 B CN 108768195B
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Prior art keywords
circuit
bridge arm
electrically connected
module
terminal
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CN108768195A (en
Inventor
符松格
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Beijing Etechwin Electric Co Ltd
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Beijing Etechwin Electric Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/487—Neutral point clamped inverters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The embodiment of the application provides a power circuit, a power module and a converter, wherein the power circuit comprises: the bus support capacitor module comprises a three-level bridge arm module and a bus support capacitor module, wherein the three-level bridge arm module comprises at least one bridge arm; the positive direct current terminal of the bridge arm is electrically connected with the bus support capacitor module through a first connecting circuit; the negative direct current terminal of the bridge arm is electrically connected with the bus support capacitor module through a second connecting circuit; the neutral terminal of the bridge arm is electrically connected with the bus support capacitor module through a third connecting circuit and a fourth connecting circuit respectively; an included angle between the first connection circuit and the third connection circuit is smaller than a preset angle threshold value, and/or an included angle between the second connection circuit and the fourth connection circuit is smaller than a preset angle threshold value. In the embodiment of the application, the current input path and the circuit output path are almost parallel to each other and the current directions are opposite, so that most of magnetic fields of two paths of current are mutually offset, parasitic inductance on the current transmission path can be reduced, and the stability of a bridge arm during switching can be improved.

Description

Power circuit, power module and converter
Technical Field
The application relates to the technical field of converters, in particular to a power circuit, a power module and a converter.
Background
With the development of power electronic technology, in high-power grid-connected devices such as wind power converters, a T-type three-level topology is gradually applied to improve the conversion efficiency of the converters and reduce the cost of a heat dissipation system. Because there are few kinds of Insulated Gate Bipolar Transistor (IGBT) modules packaged with a complete T-type three-level bridge arm, a solution of T-NPC (T-type-Neutral Point Clamped) three-level bridge arm is generally adopted in the market, in which a half-bridge IGBT module and a common emitter IGBT module are spliced. In the scheme, the half-bridge IGBT module is connected between the positive end and the negative end of the direct current bus and is called a non-zero level bridge arm, and the common emitter IGBT module is electrically connected with the neutral end of the direct current bus and is called a zero level bridge arm.
Because two independent IGBT modules are spliced to form a T-NPC bridge arm, when a current is switched from a non-zero level bridge arm to a zero level bridge arm to work in the working process of the T-NPC bridge arm, a back electromotive force generated by a stray inductance (or called parasitic inductance) on a current switching path can be superposed on a direct current bus voltage, so that the voltage stress of the IGBT in the switching process is improved, and the IGBT is very sensitive to the voltage stress, so that the stray inductance on the current switching path needs to be reduced as much as possible.
Disclosure of Invention
The application provides a power circuit, a power module and a converter, which are used for solving the technical problem that stray inductance on a current switching path is large in the prior art.
In a first aspect, the present application provides a power circuit comprising: the bus support capacitor module comprises a three-level bridge arm module and a bus support capacitor module, wherein the three-level bridge arm module comprises at least one bridge arm;
the positive direct current terminal of the bridge arm is electrically connected with the bus support capacitor module through a first connecting circuit; the negative direct current terminal of the bridge arm is electrically connected with the bus support capacitor module through a second connecting circuit; the neutral terminal of the bridge arm is electrically connected with the bus support capacitor module through a third connecting circuit and a fourth connecting circuit respectively;
an included angle between the first connection circuit and the third connection circuit is smaller than a preset angle threshold value, and/or an included angle between the second connection circuit and the fourth connection circuit is smaller than a preset angle threshold value.
In a second aspect, the present application provides a power module comprising: the power circuit comprises a laminated busbar and a power circuit shown in the first aspect of the application;
the three-level bridge arm module and the bus support capacitor module are arranged on the laminated busbar;
the three-level bridge arm module is arranged in the first area;
the bus supporting capacitor module is arranged in a second area opposite to the first area;
the laminated busbar comprises: the bus bar comprises a first bus bar provided with a first connecting circuit, a second bus bar provided with a second connecting circuit, and a third bus bar provided with a third connecting circuit and a fourth connecting circuit.
In a third aspect, the present application provides a power converter comprising the power module shown in the second aspect of the present application.
The technical scheme provided by the embodiment of the application at least has the following beneficial effects:
the three-level bridge arm module and the bus support capacitor module are correspondingly and electrically connected through the connecting circuit, and an included angle formed by a current input path and a current output path of the three-level bridge arm module is smaller than a preset angle threshold value, so that the current input path and the circuit output path are almost parallel to each other and the current directions are opposite, most of magnetic fields of two paths of current are mutually offset, stray inductance on a current transmission path is reduced to a lower value, counter-potentials generated when different bridge arms in the three-level bridge arm module are switched are greatly reduced, voltage stress of power electronic components in the bridge arms in the switching process is greatly reduced, the stability of the power electronic components in the bridge arms can be improved, and the stability of the whole three-level bridge arm module is improved.
Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the description of the embodiments of the present application will be briefly described below.
Fig. 1 is a schematic circuit diagram of a three-level topology circuit in the prior art;
fig. 2 is a schematic circuit diagram illustrating a conventional single-phase three-level topology circuit connected to a load;
fig. 3 is a schematic circuit diagram illustrating a conventional three-phase three-level topology circuit connected to a load;
fig. 4 is a schematic diagram illustrating a structure and a current path of a single-phase power module according to an embodiment of the present disclosure;
fig. 5 is a schematic diagram of a structure and a current path of another single-phase power module according to an embodiment of the present disclosure;
FIG. 6 is a schematic circuit diagram of the single phase power module shown in FIG. 5;
fig. 7 is a schematic diagram of a structure and a current path of a bi-phase power module according to an embodiment of the present disclosure;
FIG. 8 is a schematic circuit diagram of the bi-phase power module of FIG. 7;
fig. 9 is a schematic diagram of a structure and a current path of a three-phase power module according to an embodiment of the present disclosure.
Detailed Description
Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.
To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
The terms referred to in this application will first be introduced and explained:
three levels: a power electronic technology capable of outputting direct current positive (DC +), Neutral Point (NP) and direct current negative (DC-) potentials.
A T-NPC (T-type-Neutral Point Clamped) three-level topology circuit, referred to as T-type NPC for short, which is one of three-level topologies.
An IGBT (Insulated Gate Bipolar Transistor) is a device that can be controlled to perform a fast switching operation.
Laminated busbar: a technology for reducing stray inductance of a direct current link by pressing direct current bus bars together.
Stray inductance: the parasitic parameters of the conductor itself, also called parasitic inductance.
DC support capacitance: in power electronics technology, the power supply device generally plays a role in supporting a direct-current bus voltage, providing alternating-current side ripple current and providing IGBT (insulated gate bipolar transistor) switching transient energy.
The inventor of the present application finds that a T-NPC three-level topology circuit exists, the circuit principle of which is shown in fig. 1, and the T-NPC three-level topology circuit includes a three-level bridge arm, a capacitor bank C1 and a capacitor bank C2, the bridge arm horizontally drawn in fig. 1 is a horizontal tube (zero-level bridge arm), the bridge arm longitudinally drawn is a vertical tube (non-zero-level bridge arm), the capacitor bank C1 and the capacitor bank C2 are connected in series to support a direct-current bus voltage, a midpoint of the capacitor banks C1 and C2 is connected to a Neutral Point (NP), and the other two ends of the capacitor banks C1 and C2 are respectively connected to a direct-current positive (DC +) and a direct-current negative (DC-).
The dc support capacitor banks C1 and C2 are constantly in a charging or discharging state during the switching cycle of the IGBT. When the DC support capacitor bank C1 discharges, a path exists from DC + to the three-level bridge arm and from NP to the capacitor bank C1; when DC backup capacitor bank C1 is charged, a path exists from NP to the three-level arm and DC + to capacitor bank C1. When the DC support capacitor bank C2 discharges, there is a path from NP into the three-level bridge arm and from DC-out to capacitor bank C2; when DC backup capacitor bank C2 is charged, there is a path from DC-to three-level bridge arm, and from NP to capacitor bank C2.
When the three-level topology circuit is connected to a load, the circuit principle is as shown in fig. 2, and when the IGBT in the horizontal tube near the NP side is turned on, a current path shown by a dotted line direction in fig. 2 is formed, that is, a discharging current flowing direction of the capacitor bank C2. In light of the foregoing current path principle of the three-level topology circuit, those skilled in the art can understand the current flow direction of the circuit shown in fig. 2 in other cases, and details thereof are not described here.
When the three-level topology circuit has three-phase legs and is connected with a load, the circuit principle is as shown in fig. 3, and the three-phase legs refer to A, B and C three phases shown in fig. 3. When the IGBTs above the AC output point in the vertical tube of the a-phase arm are turned on and the IGBTs near the AC side in the horizontal tube of the B-phase arm are turned on, a current path shown by a dotted line in fig. 3 is formed, and at this time, the capacitor bank C1 is discharged through the current path. In light of the foregoing current path principle of the three-level topology circuit, those skilled in the art can understand the current flow direction of the circuit shown in fig. 3 in other cases, and the description is omitted here.
On the current path of each circuit, the current path is all longer, and the stray inductance that exists is great, because IGBT is in quick on-off state, the current path is also in quick switching, and the existence of stray inductance will restrain the rapid change of electric current, produces a reverse potential simultaneously, superposes on the voltage of direct current capacitor group, causes the voltage rise in IGBT turn-off moment then, causes extra turn-off stress.
The application provides a power circuit, a power module and a current transformer, which aim to solve the technical problems in the prior art.
The following describes the technical solutions of the present application and how to solve the above technical problems with specific embodiments. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.
Example one
An embodiment of the present application provides a power circuit, as shown in fig. 4, the power circuit includes: the three-level bridge arm module comprises at least one bridge arm 10. The bridge leg 10 includes a common emitter circuit 12 and a half bridge circuit 11.
The positive direct current terminal DC + of each bridge arm 10 is electrically connected with the bus support capacitor module through a first connecting circuit 21; the negative direct current terminal DC-of each bridge arm 10 is electrically connected with the bus support capacitor module through a second connecting circuit 22; the neutral terminal NP of each arm 10 is electrically connected to the bus bar support capacitor module through a third connection circuit 23 and a fourth connection circuit 24, respectively.
According to different working states of the bus support capacitor module, the first connecting circuit 21, the second connecting circuit 22, the third connecting circuit 23 and the fourth connecting circuit 24 can be used as current input paths or current output paths of the three-level bridge arm module.
In the embodiment of the present application, an included angle between the first connection circuit 21 and the third connection circuit 23 is smaller than a preset angle threshold, and/or an included angle between the second connection circuit 22 and the fourth connection circuit 24 is smaller than a preset angle threshold. Wherein, the angle threshold value can be set according to actual requirements.
According to the stray inductance theory, when the included angle between the two current transmission paths is small, the magnetic fields can be mutually offset to a large extent, and further the stray inductance of the current transmission paths is obviously reduced; and the smaller the included angle, the more obvious the magnetic field cancellation is, and the lower the stray inductance of the current transmission path is.
The first embodiment of the present application further provides another possible implementation manner, and with reference to fig. 4 to 6, the following is specifically introduced:
optionally, the power circuit provided by the embodiment of the application is a T-NPC three-level topology circuit.
Optionally, the bridge arm 10 includes a half-bridge circuit 11 and a common emitter circuit 12 electrically connected; the first end of the half-bridge circuit 11 is a positive direct current terminal of the belonging bridge arm 10, and the second end is a negative direct current terminal of the belonging bridge arm 10; the common emitter circuit 12 has a first end electrically connected to the ac output terminal of the half-bridge circuit 11 and is an ac output terminal of the associated arm 10, and a second end serving as a neutral terminal of the associated arm 10.
Optionally, the half-bridge circuit 11 includes a first power unit and a second power unit connected in series; the common emitter circuit 12 includes a third power unit and a fourth power unit connected in series. The first end of the first power unit is a positive direct current terminal of the bridge arm to which the first power unit belongs, and the second end of the first power unit is an alternating current output terminal of the bridge arm to which the first power unit belongs; the first end of the second power unit is electrically connected with the alternating current output terminal, and the second end of the second power unit is a negative direct current terminal of the bridge arm to which the second power unit belongs; the first end of the third power unit is electrically connected with the alternating current output terminal, and the second end of the third power unit is electrically connected with the first end of the fourth power unit; and the second end of the fourth power unit is a neutral terminal of the bridge arm to which the fourth power unit belongs.
Optionally, the first power unit, the second power unit, the third power unit, and the fourth power unit are all IGBTs. The first end and the second end of the first power unit are respectively a collector and an emitter of the first IGBT; the first end and the second end of the second power unit are respectively a collector and an emitter of the second IGBT; the first end and the second end of the third power unit are respectively a collector and an emitter of the third IGBT; the first end and the second end of the fourth power unit are respectively an emitter and a collector of the fourth IGBT.
Optionally, the bus bar supporting capacitor module includes a first capacitor bank and a second capacitor bank; the first capacitor group is electrically connected with the positive direct current terminal and the neutral terminal of the bridge arm 10 through a first connecting circuit 21 and a third connecting circuit 23 respectively; the second capacitor group is electrically connected to the negative dc terminal and the neutral terminal of the arm 10 through a second connection circuit 22 and a fourth connection circuit 24, respectively.
Optionally, the first capacitor bank includes at least one first capacitor, and the second capacitor bank includes at least one second capacitor; when the number of the first capacitors is more than two, all the first capacitors are connected in parallel; when the number of the second capacitors is more than two, the second capacitors are connected in parallel.
Further, a first end of first capacitor C1 is electrically connected to the positive dc terminal of bridge arm 10 through first connection circuit 21, and a second end is electrically connected to the neutral terminal of bridge arm 10 through third connection circuit 23; second capacitor C2 has a first end electrically connected to the neutral terminal of arm 10 via fourth connecting circuit 24 and a second end electrically connected to the negative dc terminal of arm 10 via second connecting circuit 22.
Specifically, the first capacitor C1 and the second capacitor C2 each include a positive terminal and a negative terminal; the positive terminal of the first capacitor C1 is electrically connected to the positive dc terminal of each arm 10 through the first connection circuit 21, and the negative terminal is electrically connected to the neutral terminal of each arm 10 through the third connection circuit 23; a positive terminal of second capacitor C2 is electrically connected to the neutral terminal of arm 10 via fourth connection circuit 24, and a negative terminal is electrically connected to the negative dc terminal of arm 10 via second connection circuit 22.
The specific principle of the power circuit provided in the embodiment of the present application will be described in detail in the following section, and will not be described herein again.
Therefore, the first embodiment of the present application has at least the following effects:
the three-level bridge arm module and the bus support capacitor module are correspondingly and electrically connected through the connecting circuit, and an included angle formed by a current input path and a current output path of the three-level bridge arm module is smaller than a preset angle threshold value, so that the current input path and the circuit output path are almost parallel to each other and the current directions are opposite, most of magnetic fields of two paths of current are mutually offset, parasitic inductance on a current transmission path is reduced to a lower value, counter-potentials generated when different bridge arms in the three-level bridge arm module are switched are greatly reduced, voltage stress of power electronic components in the bridge arms in the switching process is greatly reduced, the stability of the power electronic components in the bridge arms can be improved, and the stability of the whole three-level bridge arm module is improved.
Example two
Based on the same inventive concept, a second embodiment of the present application provides a power module, including: laminated busbar and as in the first embodiment of this application arbitrary power circuit.
In the embodiment of the application, a three-level bridge arm module and a bus support capacitor module in a power circuit are arranged on a laminated busbar, and the three-level bridge arm module is arranged in a first area; and a bus support capacitor module in the power circuit is arranged in a second area opposite to the first area.
In an embodiment of the present application, the laminated busbar includes: the bus bar comprises a first bus bar provided with a first connecting circuit, a second bus bar provided with a second connecting circuit, and a third bus bar provided with a third connecting circuit and a fourth connecting circuit.
The second embodiment of the present application further provides another possible implementation manner, which is specifically introduced as follows:
optionally, the number of the three-level bridge arm modules is at least one, and each three-level bridge arm module is arranged in the first area; each three-level bridge arm module comprises an even number of bridge arms 10 connected in parallel, and a first bridge arm and a second bridge arm in the even number of bridge arms 10 are centrosymmetric relative to a specified symmetric point. In fig. 5, 7 and 9, the designated symmetrical points are shown by black dots in fig. 5, 7 and 9.
When the number of the three-level bridge arm modules is one, the power module is a power module with a single-phase bridge arm (referred to as a single-phase power module for short). As shown in fig. 4 to 6, the circuit shown in fig. 4 is a case where the three-level bridge arm module includes one bridge arm 10, and the circuit shown in fig. 5 is a case where the three-level bridge arm module includes two bridge arms 10, namely, a first bridge arm and a second bridge arm, and the two bridge arms 10 are centrosymmetric with respect to a designated symmetric point.
Fig. 6 shows a schematic circuit diagram of the single-phase power module shown in fig. 5, and a dashed line with an arrow in fig. 6 shows a current path when the second capacitor C2 discharges, and a direction indicated by the arrow on the dashed line is a current direction when the second capacitor C2 discharges.
When there are an even number of arms 10 in the three-level arm module, the first arm is connected in parallel with the second arm, and taking the two arms shown in fig. 5 as an example, specifically, the half-bridge circuit 11 in the first arm (the upper half arm 10 in fig. 5) is connected in parallel with the half-bridge circuit in the second arm (the upper half arm 10 in fig. 5), and the common emitter circuit 12 in the first arm is connected in parallel with the common emitter circuit 12 in the second arm.
When the number of the three-level bridge arm modules is two, the power module is a power module with a two-phase bridge arm (referred to as a two-phase power module), as shown in fig. 7. Fig. 8 shows a circuit schematic of the two-phase power of fig. 7. When the number of the three-level bridge arm modules is three, the power module is a power module with a three-phase bridge arm (referred to as a three-phase power module), as shown in fig. 9.
Each of the three-level bridge arm modules in the circuits shown in fig. 7 and 9 includes two bridge arms 10, namely a first bridge arm and a second bridge arm, and the two bridge arms 10 are centrosymmetric with respect to a designated symmetric point.
Because the first bridge arm and the second bridge arm are centrosymmetric, the current transmission paths between the two bridge arms 10 and the bus support capacitor module are basically equal, the impedances are close to be consistent, and the parallel current equalizing effect is favorably enhanced.
Optionally, the power module provided in this embodiment of the application further includes an ac bus, the ac output terminal of the bridge arm is disposed at a position corresponding to the ac bus in the first region, and the ac output terminal is electrically connected to the ac bus.
Further, the ac busbar may be an ac busbar 14. Specifically, the N-phase power module may include N ac busbar rows 14 respectively corresponding to N phases, the ac output terminal of each phase is electrically connected to the ac busbar row 14 corresponding to the phase, and the output current of the ac output terminal of each phase may be led out by the corresponding one of the ac busbar rows 14. Wherein N is an integer greater than zero. Optionally, the ac busbar 14 is not overlapped with the laminated busbar 13.
For example, when the power module is the single-phase power module shown in fig. 4 or 5, the single-phase power module includes an ac busbar 14, and each ac output terminal of the single-phase power module is electrically connected to the ac busbar 14; when the power module is the two-phase power module shown in fig. 7, the ac output terminals of the a phase and the B phase are electrically connected to the ac busbar 14 of the a phase and the B phase, respectively; when the power module is a three-phase power module shown in fig. 9, the ac output terminals of the a, B, and C phases are electrically connected to the ac busbar 14 of the a, B, and C phases, respectively.
Optionally, the power module provided by the embodiment of the application can be built by adopting an IGBT module packaged by 62 mm.
Optionally, the first capacitor bank and the second capacitor bank in the bus support capacitor module are respectively arranged at a position corresponding to the first bridge arm in the second region and a position corresponding to the second bridge arm in the second region; for example, the connection of the two terminals of the first capacitor can be directed in the direction of the first leg and the connection of the two terminals of the second capacitor can be directed in the direction of the second leg.
Optionally, the first busbar, the second busbar and the third busbar are respectively a positive busbar, a negative busbar and a zero busbar; the zero busbar is arranged between the positive busbar and the negative busbar.
Each bridge arm 10 is electrically connected with the first capacitor C1 and the second capacitor C2 of the bus capacitor support module through the three-layer laminated busbar 13, and the stray inductance generated in the current transmission process can be further reduced by offsetting magnetic fields generated by opposite current paths in adjacent layers in the laminated busbar 13.
The structure and principle of the power module provided by the embodiment of the present application are further described below by taking the power module with a single-phase bridge arm shown in fig. 4 and 5 as an example:
in the embodiment of the present application, the positive dc terminal, the negative dc terminal, and the neutral terminal of each bridge arm 10 are electrically connected to the positive current end, the negative current end, and the neutral point of the dc bus respectively. The dc bus may be a dc bus bar, and further, the dc bus bar may be a laminated bus bar.
The positive direct current terminal and the negative direct current terminal of each bridge arm 10 are respectively and electrically connected with the bus support capacitor module through a first connecting circuit 21 on the positive bus bar and a second connecting circuit 22 on the negative bus bar; and a neutral terminal of each bridge arm 10 is electrically connected with the bus support capacitor module through a third connecting circuit 23 and a fourth connecting circuit 24 on the zero busbar respectively. The positive busbar, the negative busbar and the zero busbar are respectively a positive current end, a negative current end and a neutral end of the direct current busbar.
Specifically, the positive dc terminal of the bridge arm 10 is electrically connected to a first capacitor C1 in the bus bar supported capacitor module, the negative dc terminal is electrically connected to a second capacitor C2 in the bus bar supported capacitor module, and both the first capacitor C1 and the second capacitor C2 are electrically connected to the neutral terminal.
Each bridge arm 10 is electrically connected with the bus capacitor support module through three laminated busbars 13, and because the adjacent layers of the laminated busbars 13 are parallel and the current transmission directions of the connecting circuits in the adjacent layers are opposite, magnetic fields generated by current paths of different layers can be mutually offset, so that stray inductance generated in the current transmission process is reduced.
When first capacitor C1 discharges, current flows from the DC + terminal to arm 10 along first connection circuit 21 and out to first capacitor C1 from the NP terminal along third connection circuit 23; when the first capacitor C1 is charged, the current path is reversed and is not shown in fig. 5.
When second capacitor C2 discharges, current flows along fourth connecting circuit 24 from the NP terminal into leg 10 and along second connecting circuit 22 from the DC terminal to the current path of second capacitor C2; when the second capacitor C2 is charged, the current path is reversed; the current path involving the second capacitor C2 is not shown in fig. 5.
Optionally, the first connection circuit 21, the second connection circuit 22, the third connection circuit 23, and the fourth connection circuit 24 are all smaller than a preset length threshold; the length threshold value can be set according to actual requirements.
The embodiment of the application realizes the purposes of reducing the transmission path and the switching path of the current by reducing the length of each connecting circuit, thereby reducing the stray inductance generated during current switching.
Optionally, a first end of a half-bridge circuit in the bridge arm is electrically connected with the positive bus bar as a positive dc terminal of the bridge arm, and a second end of the half-bridge circuit is electrically connected with the negative bus bar as a negative dc terminal of the bridge arm;
the first end of the common emitter circuit in the bridge arm is used as an alternating current output terminal of the bridge arm to be electrically connected with an alternating current output end of the half-bridge circuit, and the second end of the common emitter circuit is used as a neutral terminal of the bridge arm to be electrically connected with a zero bus bar.
Optionally, a first end of a first power unit in the half-bridge circuit is electrically connected with the positive busbar, and a second end is electrically connected with the alternating current output end; a first end of a second power unit in the half-bridge circuit is electrically connected with the alternating current output end, and a second end of the second power unit is electrically connected with the negative busbar; the first end of a third power unit in the common emitter circuit is electrically connected with the alternating current output end, and the second end of the third power unit is electrically connected with the first end of a fourth power unit; and the second end of the fourth power unit in the common emitter circuit is electrically connected with the zero bus bar.
The following description is made of specific principles of the power circuit and the power module provided in the embodiments of the present application:
when first capacitor C1 discharges, current flows along first connecting circuit 21 from the DC + terminal to arm 10 and along third connecting circuit 23 from the NP terminal to first capacitor C1, the current path is shown by the first two dotted lines from top to bottom in fig. 4 and the dotted lines in fig. 5, and the current direction is shown by the arrows on the corresponding dotted lines in fig. 4 and 5; when the first capacitor C1 is charged, the current path is in the opposite direction, which is shown by the first two dotted lines from top to bottom in fig. 4 and the dotted line in fig. 5, and the current direction is not shown in fig. 4 and fig. 5, but does not affect the understanding of the technical solution of the present application by those skilled in the art.
When second capacitor C2 discharges, current flows along fourth connecting circuit 24 from NP terminal to leg 10 and along second connecting circuit 22 from DC terminal to second capacitor C2, the current path is shown by the last two dashed lines from top to bottom in fig. 4 and the dashed line with an arrow in fig. 6, and the current direction is shown by the direction of the arrow on the corresponding dashed line in fig. 4 and 6; when the second capacitor C2 is charged, the current path is in the opposite direction, which is shown by the two last dotted lines from top to bottom in fig. 4 and the dotted line with an arrow in fig. 6, and the current direction is not shown in fig. 4 and fig. 6, but does not affect the understanding of the technical solution of the present application by those skilled in the art.
Neither of the current paths related to the second capacitor C2 is shown in fig. 5, and referring to fig. 4 and 6, those skilled in the art can understand that there are corresponding current paths and current directions in fig. 5, which are not described herein.
Optionally, the sum of the lengths of the first connection circuit 21 and the third connection circuit 23 is smaller than a preset first length threshold; the sum of the lengths of the second connection circuit 22 and the fourth connection circuit 24 is smaller than a preset second length threshold. The first length threshold and the second length threshold can be set according to actual requirements.
By setting the first length threshold, the current input and output paths formed by the first connection circuit 21 and the third connection circuit 23 when the first capacitor C1 is charged or discharged can be reduced; by setting the second length threshold, the current input and output paths formed by the second connection circuit 22 and the fourth connection circuit 24 when the second capacitor C2 is charged or discharged can be reduced. The whole current transmission path and the switching path can be reduced, and therefore stray inductance generated during whole current switching is reduced.
The principle of the two-phase or three-phase power module shown in fig. 7 to 9 is similar to that of the single-phase power module shown in fig. 5 and 6, and the principle of the two-phase power module will be described in the following by taking the structure and circuit principle shown in fig. 7 and 8 as an example: in the two-phase power module shown in fig. 7 and 8, when the first capacitor C1 is discharged, a current flows into the bridge arm 10 from the DC + terminal along the first connection circuit 21 of the a-phase, and flows out to the first capacitor C1 from the NP terminal along the third connection circuit 23 of the B-phase, the current path thereof is shown by a dotted line in fig. 7 and 8, and the current direction thereof is shown by an arrow on the dotted line in fig. 7 and 8; when the first capacitor C1 is charged, the current direction in the current path is opposite, the current path is shown by the dotted line in fig. 7 and 8, and the current direction is not shown in fig. 7 and 8, but does not affect the understanding of the technical solution of the present application by those skilled in the art.
From the above analysis, when the first capacitor C1 is charged or discharged, the first connection circuit 21 of the a-phase three-level bridge arm module and the third connection circuit 23 of the B-phase three-level bridge arm module form an input path and an output path of the same current loop, and the sum of the lengths of the first connection circuit 21 of the a-phase three-level bridge arm module and the third connection circuit 23 of the B-phase three-level bridge arm module is set to be smaller than a preset third length threshold, so that the whole current transmission path and the whole switching path can be reduced, and thus the stray inductance generated during the whole current switching can be reduced.
When the second capacitor C2 is charged or discharged, the principle is similar to that of the first capacitor C1, and the details are not repeated herein.
The technical scheme of the second embodiment of the application has at least the following beneficial effects:
1) the three-level bridge arm module is correspondingly and electrically connected with the bus support capacitor module by adopting a connecting circuit, and an included angle formed by a current input path and a current output path of the three-level bridge arm module is smaller than a preset angle threshold value, so that the parasitic inductance on a current transmission path is reduced to a lower value;
2) the purpose of reducing the transmission path and the switching path of the current can be achieved by reducing the length of each connecting circuit, so that the stray inductance generated during current switching is reduced;
3) by reducing stray inductance in the current transmission path, the judgment voltage stress of the power unit can be effectively reduced;
4) at least two bridge arms in the three-level bridge arm module are connected in parallel, so that the current equalizing effect is favorably realized; because the first bridge arm and the second bridge arm in the three-level bridge arm are centrosymmetric, the current transmission paths between the two bridge arms and the bus support capacitor module are basically equal, the impedances are close to be consistent, and the parallel current equalizing effect can be enhanced.
EXAMPLE III
Based on the same inventive concept, the third embodiment of the present application provides a converter, which includes any one of the power modules provided in the second embodiment of the present application.
Those skilled in the art can understand that the converter provided in the embodiment of the present application may further include any one or more circuit structures of a rectifier circuit, a filter circuit, a control circuit, and the like, which are not described herein again.
Based on any power module provided by the second embodiment of the present application, the third embodiment of the present application has at least the following beneficial effects:
1) the three-level bridge arm module and the bus support capacitor module are correspondingly and electrically connected through the connecting circuit, and an included angle formed by a current input path and a current output path of the three-level bridge arm module is smaller than a preset angle threshold value, so that the current input path and the circuit output path are almost parallel to each other and the current directions are opposite, most of magnetic fields of two paths of current are mutually offset, stray inductance on a current transmission path is reduced to a lower value, counter-potentials generated during switching among different bridge arms in the three-level bridge arm module are greatly reduced, voltage stress of power electronic components in the bridge arms in the switching process is greatly reduced, the stability of the power electronic components in the bridge arms can be improved, the stability during switching of the bridge arms can be improved, and the stability of the whole three-level bridge arm module is improved.
2) The three-level bridge arm module of each phase comprises an even number of parallel bridge arms, and compared with the existing single bridge arm, the even number of parallel bridge arms is beneficial to sharing output current on average, improving the current sharing effect, reducing the load of current transmission of each bridge arm, improving the stability and reliability of each bridge arm and prolonging the service life of the bridge arms.
3) In the application, the first bridge arm and the second bridge arm in even number of bridge arms in the three-level bridge arm module are arranged in a mirror image mode, so that the current transmission paths of two bridge arms 10 arranged in the mirror image mode and the bus support capacitor module are basically equal, the impedances are close to be consistent, and the parallel current sharing effect can be enhanced.
4) By reducing the length of each connecting circuit, the purpose of reducing the transmission path and the switching path of the current can be achieved, and therefore stray inductance generated during current switching is reduced.
The foregoing is only a partial embodiment of the present application, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the principle of the present application, and these modifications and decorations should also be regarded as the protection scope of the present application.

Claims (14)

1. A power circuit, comprising: the bus support capacitor module comprises a three-level bridge arm module and a bus support capacitor module, wherein the three-level bridge arm module comprises at least one bridge arm;
the positive direct current terminal of the bridge arm is electrically connected with the bus support capacitor module through a first connecting circuit; the negative direct current terminal of the bridge arm is electrically connected with the bus support capacitor module through a second connecting circuit; the neutral terminal of the bridge arm is electrically connected with the bus support capacitor module through a third connecting circuit and a fourth connecting circuit respectively;
the first connecting circuit is arranged on a first bus bar in the laminated bus bar, the second connecting circuit is arranged on a second bus bar in the laminated bus bar, and the third connecting circuit and the fourth connecting circuit are both arranged on a third bus bar in the laminated bus bar; the third busbar is positioned between the first busbar and the second busbar;
an included angle between the first connecting circuit and the third connecting circuit is smaller than a preset angle threshold value, and/or an included angle between the second connecting circuit and the fourth connecting circuit is smaller than a preset angle threshold value;
when the three-level bridge arm module comprises an even number of parallel-connected bridge arms, a first bridge arm and a second bridge arm in the even number of bridge arms are centrosymmetric relative to a specified symmetric point.
2. The power circuit of claim 1, wherein the power circuit is a T-NPC three-level topology circuit.
3. The power circuit of claim 2, wherein the leg comprises a half-bridge circuit and a common-emitter circuit electrically connected;
the first end of the half-bridge circuit is a positive direct current terminal of the bridge arm, and the second end of the half-bridge circuit is a negative direct current terminal of the bridge arm;
the first end of the common emitter circuit is electrically connected with the alternating current output end of the half-bridge circuit and is an alternating current output terminal of the bridge arm, and the second end of the common emitter circuit is a neutral terminal of the bridge arm.
4. The power circuit of claim 1, wherein the bus bar support capacitance module comprises a first capacitance group and a second capacitance group;
the first capacitor bank is electrically connected with the positive direct current terminal and the neutral terminal of the bridge arm respectively through the first connecting circuit and the third connecting circuit;
the second capacitor bank is electrically connected with the negative direct current terminal and the neutral terminal of the bridge arm respectively through the second connecting circuit and the fourth connecting circuit.
5. The power circuit of claim 4, wherein the first capacitor bank comprises at least one first capacitor and the second capacitor bank comprises at least one second capacitor;
when the number of the first capacitors is more than two, all the first capacitors are connected in parallel; when the number of the second capacitors is more than two, all the second capacitors are connected in parallel;
the first end of the first capacitor is electrically connected with the positive direct current terminal of the bridge arm through the first connecting circuit, and the second end of the first capacitor is electrically connected with the neutral terminal of the bridge arm through the third connecting circuit;
and the first end of the second capacitor is electrically connected with the neutral terminal of the bridge arm through the fourth connecting circuit, and the second end of the second capacitor is electrically connected with the negative direct current terminal of the bridge arm through the second connecting circuit.
6. A power module, comprising: a laminated busbar and a power circuit as claimed in any one of claims 1 to 5;
the three-level bridge arm module and the bus support capacitor module are arranged on the laminated busbar;
the three-level bridge arm module is arranged in a first area;
the bus supporting capacitor module is arranged in a second area opposite to the first area;
the laminated busbar comprises: the bus bar comprises a first bus bar provided with a first connecting circuit, a second bus bar provided with a second connecting circuit, and a third bus bar provided with a third connecting circuit and a fourth connecting circuit.
7. The power module of claim 6, wherein the sum of the lengths of the first connection circuit and the third connection circuit is less than a preset first length threshold; the sum of the lengths of the second connecting circuit and the fourth connecting circuit is smaller than a preset second length threshold value.
8. The power module of claim 7, wherein the number of the three-level bridge arm modules is at least one, and each three-level bridge arm module is disposed in the first area.
9. The power module of claim 8, further comprising an ac bus;
and the alternating current output terminal of the bridge arm is arranged at a position corresponding to the alternating current bus in the first area, and the alternating current output terminal is electrically connected with the alternating current bus.
10. The power module of claim 8, wherein the first capacitor bank and the second capacitor bank of the bus bar support capacitor module are respectively disposed at a position corresponding to the first bridge arm in the second region and at a position corresponding to the second bridge arm in the second region.
11. The power module of claim 8,
the first busbar, the second busbar and the third busbar are respectively a positive busbar, a negative busbar and a zero busbar;
the zero busbar is arranged between the positive busbar and the negative busbar.
12. The power module of claim 11, wherein a first end of a half-bridge circuit in the bridge arm is electrically connected to a positive bus bar as a positive dc terminal of the bridge arm, and a second end is electrically connected to the negative bus bar as a negative dc terminal of the bridge arm;
and the first end of the common emitter circuit in the bridge arm is used as an alternating current output terminal of the bridge arm and is electrically connected with the alternating current output end of the half-bridge circuit, and the second end of the common emitter circuit is used as a neutral terminal of the bridge arm and is electrically connected with the zero bus bar.
13. The power module of claim 12 wherein a first terminal of a first power cell in the half-bridge circuit is electrically connected to the positive busbar and a second terminal is electrically connected to the ac output terminal;
the first end of a second power unit in the half-bridge circuit is electrically connected with the alternating current output end, and the second end of the second power unit is electrically connected with a negative bus bar;
the first end of a third power unit in the common emitter circuit is electrically connected with the alternating current output end, and the second end of the third power unit is electrically connected with the first end of a fourth power unit;
and the second end of the fourth power unit in the common emitter circuit is electrically connected with a zero bus bar.
14. A power converter comprising a power module according to any one of claims 6-13.
CN201810696727.6A 2018-06-29 2018-06-29 Power circuit, power module and converter Active CN108768195B (en)

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