CN217486381U - Filter device and frequency converter - Google Patents
Filter device and frequency converter Download PDFInfo
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- CN217486381U CN217486381U CN202221128840.2U CN202221128840U CN217486381U CN 217486381 U CN217486381 U CN 217486381U CN 202221128840 U CN202221128840 U CN 202221128840U CN 217486381 U CN217486381 U CN 217486381U
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Abstract
The utility model provides a filtering device and converter, filtering device includes: the first end of each reactance device is connected to the input end of the three-phase half bridge of the frequency converter module, and the second end of each reactance device is used as the output end of the filter device and is connected to the output end of the next filter device connected in parallel; a plurality of resistive devices, a first end of each resistive device being connected to a first end of a corresponding reactive device; the first end of each capacitive device is connected to the second end of the corresponding resistor device, and the second end of each capacitive device is connected to the negative end of the direct current bus of the three-phase half bridge; wherein a path impedance formed between the resistive device and the capacitive device is less than a path impedance formed between the reactive devices. The utility model discloses can effectual reduction circulation heavy current to prevent that the converter module from damaging because of the circulation, also can reduce the high frequency signal output of converter simultaneously, reduce its electromagnetic interference to the outside.
Description
Technical Field
The utility model relates to a converter technical field especially relates to a filtering device and converter.
Background
With the increase of application requirements, a high-power frequency converter can be generally obtained by connecting frequency converter modules with lower power in parallel. Modular and standardized power modules are adopted for superposition to form any required redundant system, and the method is one of the preferable schemes for realizing the requirements of performance, capacity, reliability, safety and expansibility of the frequency converter.
The parallel connection of the modular frequency converters may cause the generation of system circulation, and the existence of circulation may also cause the uneven current of Insulated Gate Bipolar Transistors (IGBTs) which are key components of the frequency converters, so that the IGBT is in a serious heating state for a long time and is finally damaged, and if circulation control is not ideal, the control performance and the operating efficiency of the system are greatly reduced, so that the problem of circulation is solved and becomes the core problem of the parallel connection of the frequency converters.
SUMMERY OF THE UTILITY MODEL
The utility model provides a filtering device and converter for solve among the prior art by the parallelly connected produced circulation problem of a plurality of converter modules.
In a first aspect, the utility model provides a filtering device is applied to the converter, the converter comprises a plurality of converter modules in parallel, its characterized in that, every converter module corresponds a filtering device, filtering device includes:
each reactance device is provided with a first end and a second end, the first end is connected to the input end of the three-phase half bridge of the frequency converter module, and the second end serves as the output end of the filter device and is connected to the output end of the next filter device connected in parallel;
a plurality of resistive devices, a first end of each resistive device being connected to a first end of a corresponding reactive device;
a plurality of capacitive devices, a first end of each capacitive device being connected to a second end of a corresponding resistive device, a second end of each capacitive device being connected to a negative terminal of a dc bus of the three-phase half bridge;
wherein a path impedance formed between the resistive device and the capacitive device is less than a path impedance formed between the reactive devices.
In an embodiment of the present invention, the plurality of reactance devices include a first reactance device, a second reactance device and a third reactance device, the first reactance device, the second reactance device and the first end of the third reactance device all correspond to the three-phase input end of the three-phase half-bridge connected in series to the frequency converter module.
In an embodiment of the present invention, the plurality of resistor devices include a first resistor device, a second resistor device and a third resistor device, the first resistor device, the second resistor device and the first end of the third resistor device are correspondingly connected to the first reactance device, the second reactance device and the first end of the third reactance device.
In an embodiment of the present invention, the plurality of capacitor devices include a first capacitor device, a second capacitor device and a third capacitor device, the first capacitor device, the second capacitor device and the first end of the third capacitor device are all correspondingly connected to the second ends of the first resistor device, the second resistor device and the third resistor device, the first capacitor device, the second capacitor device and the second end of the third capacitor device are all connected to the negative end of the dc bus of the three-phase half-bridge.
In an embodiment of the present invention, the minimum value of the inductance value L of each reactance device is expressed as:
wherein, V D Represents the maximum value of the direct current bus, delta t represents the maximum value of the pulse delay, I Δmax Representing the maximum allowable current difference and w representing the fundamental angular frequency.
In an embodiment of the present invention, the value of each of the resistor device and the capacitor device satisfies the following equation:
wherein R represents a resistance value of each resistive device, C represents a capacitance value of each capacitive device, L represents an inductance value of each inductive device, and w n And the angular frequency corresponding to the maximum delay time of the pulse between the parallel frequency converter modules is shown.
In a second aspect, the present invention further provides a frequency converter, including:
a plurality of frequency converter modules, each connected in parallel;
a plurality of filtering devices, each corresponding to a frequency converter module, each filtering device being as described in any one of the above first aspect.
In an embodiment of the present invention, each of the frequency converter modules has a positive terminal and a negative terminal, the positive terminal has a three-phase circuit connected in parallel between the negative terminals, each phase circuit is formed by two sets of switching devices connected in series, each set of switching devices includes an insulated gate bipolar transistor and a diode connected in parallel, and a connection node between the two sets of switching devices of each phase circuit is an intermediate node.
The utility model discloses an in the embodiment, the three-phase input of every converter module respectively correspond connect in the intermediate node of three-phase circuit.
In an embodiment of the present invention, a capacitor device is further connected in parallel between the positive terminal and the negative terminal.
The utility model provides a pair of filter equipment and converter through providing the filter equipment who comprises reactance device, resistance device and capacitance device, can effectual reduction circulation heavy current to prevent that the converter module from damaging because of the circulation, also can reduce the high frequency signal output of converter simultaneously, reduce its electromagnetic interference outside.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the following briefly introduces the drawings required for the embodiments or the prior art descriptions, and obviously, the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a circuit diagram of a filtering apparatus applied to a frequency converter according to the present invention;
fig. 2 is a schematic view of the present invention providing for the reduction of the formed circulation.
Detailed Description
To make the objects, technical solutions and advantages of the present invention clearer, the drawings of the present invention are combined to clearly and completely describe the technical solutions of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
The terms "first," "second," and the like in the description and in the claims, and in the drawings described above, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein.
The adoption of the parallel technology of the frequency converter modules is beneficial to the modularization of a motor driving system, the design pressure is reduced, and the redundancy of the system is realized, so that the reliability and the maintainability of the system are greatly improved. However, in an actual parallel system of frequency converter modules, due to the difference of the parameters of the frequency converter modules or due to the problem of inherent characteristics of a control system, the instantaneous values of the output voltages between the frequency converter modules cannot be completely equal, so that a certain voltage difference is inevitably existed, a circulation current is formed inside the system, and the circulation current has certain destructive influence on the power devices of the frequency converter modules.
Therefore, the utility model discloses a solve the parallelly connected produced circulation problem of a plurality of converter modules, provide a filter equipment and converter, through providing the filter equipment who comprises reactance device, resistance device and capacitance device, can effectual reduction circulation heavy current to prevent that the converter module from damaging because of the circulation, also can reduce the high frequency signal output of converter simultaneously, reduce its electromagnetic interference to the outside.
The filtering device and the frequency converter of the present invention are described below with reference to fig. 1 to 2.
Fig. 1 is a circuit diagram of a filtering apparatus applied to a frequency converter, as shown in fig. 1. The frequency converter (e.g., high power frequency converter) shown in fig. 1 is formed by connecting a plurality of frequency converter modules (4-1.., 4-n) in parallel, each frequency converter module has a positive end and a negative end, e.g., the frequency converter module 4-1 has a positive end dc + 1 And negative terminal dc- 1 (ii) a The frequency converter module 4-n has a positive terminal dc + n And negative terminal dc- n 。
Illustratively, a capacitor device C is connected in parallel between the positive terminal and the negative terminal of each frequency converter module 0 . The capacitor C 0 Is connected in parallel to a direct current transmissionA large filtering capacitor at the output end.
Illustratively, a three-phase circuit is further connected in parallel between the positive end and the negative end of each frequency converter module, each phase circuit is formed by connecting two groups of switching devices in series, each group of switching devices comprises an Insulated Gate Bipolar Transistor (IGBT) and a diode which are connected in parallel, and the Insulated Gate Bipolar Transistor (IGBT) is an N-type IGBT.
The cathode of the diode is connected with the collector of the insulated gate bipolar transistor IGBT, and the anode of the diode is connected with the emitter of the insulated gate bipolar transistor IGBT. The connection node between the two groups of switching devices of each phase circuit is an intermediate node. The six insulated gate bipolar transistors IGBTs shown in the figure may constitute a three-phase bridge structure.
Illustratively, the three-phase input of each frequency converter module is respectively connected to an intermediate node of the three-phase circuit, for example, the three-phase input (a) of the frequency converter module 4-1 1 ，b 1 ，c 1 ) Respectively correspondingly connected to the intermediate nodes (A) of the three-phase circuit 1 ，B 1 ，C 1 )。
Illustratively, each frequency converter module corresponds to a filtering arrangement, e.g. the filtering arrangement of the frequency converter module 4-1 comprises a plurality of reactive components, a plurality of resistive components and a plurality of capacitive components. The frequency converter module 4-1 is explained as follows.
One of the reactance devices 1 of the frequency converter module 4-1 has a first end and a second end, the first end is connected to the input end of the three-phase half-bridge of the frequency converter module, and the second end is used as the output end of the filter device and is connected to the output end of the next parallel filter device.
Wherein a first end of one of the resistive elements 2 of the frequency converter module 4-1 is connected to a second end of the corresponding reactive element 1. A first end of one of the capacitive devices 3 of the frequency converter module 4-1 is connected to a second end of the corresponding resistive device 2, and a second end of the capacitive device 3 is connected to a negative dc bus terminal of the three-phase half bridge.
In particular, the plurality of reactive devices includes a first reactive device, a second reactive device, and a third reactive deviceThe first ends of the first reactance device, the second reactance device and the third reactance device are correspondingly connected in series with the three-phase input end (a) of the three-phase half bridge of the frequency converter module 1 ，b 1 ，c 1 ). Said one of the reactive components 1 may be a first reactive component, a second reactive component or a third reactive component.
Specifically, the plurality of resistive devices include a first resistive device, a second resistive device, and a third resistive device, and first ends of the first resistive device, the second resistive device, and the third resistive device are respectively connected to first ends of the first reactance device, the second reactance device, and the third reactance device. The one of the resistance devices 2 may be a first resistance device, a second resistance device, or a third resistance device.
Specifically, the plurality of capacitive devices include a first capacitive device, a second capacitive device and a third capacitive device, first ends of the first capacitive device, the second capacitive device and the third capacitive device are respectively connected to second ends of the first resistive device, the second resistive device and the third resistive device, and second ends of the first capacitive device, the second capacitive device and the third capacitive device are respectively connected to a negative end N of a dc bus of the three-phase half bridge 1 . The one of the capacitor devices 3 may be a first capacitor device, a second capacitor device or a third capacitor device.
Illustratively, the minimum value of the inductance value L of each reactive device is represented as:
wherein, V D Representing the maximum value of the DC bus, Δ t representing the maximum value of the pulse delay, I Δmax Representing the maximum allowable current difference and w representing the fundamental angular frequency.
Illustratively, the value of each of the resistive and capacitive devices satisfies the following equation:
wherein R represents a resistance value of each resistive device, C represents a capacitance value of each capacitive device, L represents an inductance value of each inductive device, and w n And the angular frequency corresponding to the maximum delay time of the pulse between the parallel frequency converter modules is shown.
It should be noted that, the filtering device of the frequency converter module 4-1 is described above, and the filtering devices of the other frequency converter modules 4-2. In addition, the output end of the former filter device is connected with the output end of the latter filter device in parallel.
The working principle of the present invention is described below.
Fig. 2 is a schematic view of the present invention providing for reducing the formation of circulating currents, as shown in fig. 2. Due to the difference in the on-off time of the IGBT between the bridges of each converter module, a low resistance loop 10 as in fig. 2 is formed, which is part of the circulating current generated by the parallel converter modules.
After the access the filtering device of the present invention, for the high frequency signal at this moment, the path impedance formed by the resistance device and the capacitance device (RC) is smaller than the path impedance formed between the reactance devices (2L), and the low resistance loop 10 caused by the turn-on/off time difference of the insulated gate bipolar transistor IGBT will be consumed by the channel bypass 20 formed by the RC and reduce the external circulation.
Therefore, the filtering device provided by the utility model can effectively reduce the circulating current and prevent the module from being damaged by circulating current; and the output of high-frequency signals of the converter can be reduced, and the electromagnetic interference to the outside can be reduced.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (10)
1. A kind of filter, apply to the frequency converter, the said frequency converter is connected in parallel and made up by a plurality of frequency converter modules, characterized by that, every frequency converter module corresponds to a filter, the said filter includes:
the first end of each reactance device is connected to the input end of the three-phase half bridge of the frequency converter module, and the second end of each reactance device is used as the output end of the filter device and is connected to the output end of the next filter device connected in parallel;
a plurality of resistive devices, a first end of each resistive device being connected to a first end of a corresponding reactive device;
a plurality of capacitive devices, a first end of each capacitive device being connected to a second end of a corresponding resistive device, a second end of each capacitive device being connected to a negative terminal of a dc bus of the three-phase half bridge;
wherein a path impedance formed between the resistive device and the capacitive device is less than a path impedance formed between the reactive devices.
2. The filtering apparatus according to claim 1, wherein the plurality of reactance devices include a first reactance device, a second reactance device, and a third reactance device, and first ends of the first reactance device, the second reactance device, and the third reactance device are correspondingly connected in series to a three-phase input end of a three-phase half bridge of the frequency converter module where the reactance devices are located.
3. The filtering arrangement according to claim 2, wherein the plurality of resistive devices includes a first resistive device, a second resistive device, and a third resistive device, first ends of the first resistive device, the second resistive device, and the third resistive device each being connected to first ends of the first reactive device, the second reactive device, and the third reactive device, respectively.
4. The filtering apparatus according to claim 3, wherein the plurality of capacitive devices comprises a first capacitive device, a second capacitive device, and a third capacitive device, wherein first ends of the first capacitive device, the second capacitive device, and the third capacitive device are each connected to second ends of the first resistive device, the second resistive device, and the third resistive device, respectively, and wherein second ends of the first capacitive device, the second capacitive device, and the third capacitive device are each connected to a negative terminal of a DC bus of the three-phase half bridge.
5. The filtering arrangement, as set forth in claim 1, characterized in that the minimum value of the inductance value L of each reactive device is expressed as:
wherein, V D Representing the maximum value of the DC bus, Δ t representing the maximum value of the pulse delay, I Δmax Representing the maximum allowable current difference and w representing the fundamental angular frequency.
6. The filtering apparatus according to claim 5, wherein the value of each of the resistive device and the capacitive device satisfies the following equation:
wherein R represents a resistance value of each resistive device, C represents a capacitance value of each capacitive device, L represents an inductance value of each inductive device, and w n Representing the angular frequency corresponding to the maximum delay time of the pulses between the parallel frequency converter modules.
7. A frequency converter, comprising:
a plurality of frequency converter modules, each connected in parallel;
a plurality of filtering means, each filtering means corresponding to a frequency converter module, each filtering means being a filtering means according to any one of claims 1 to 6.
8. The frequency converter according to claim 7, wherein each frequency converter module has a positive terminal and a negative terminal, a three-phase circuit is connected in parallel between the positive terminal and the negative terminal, each phase circuit is composed of two sets of switching devices connected in series, each set of switching devices comprises an insulated gate bipolar transistor and a diode connected in parallel, and a connection node between the two sets of switching devices of each phase circuit is an intermediate node.
9. The frequency converter according to claim 8, characterized in that the three-phase input terminals of each frequency converter module are respectively connected to the intermediate nodes of the three-phase circuit.
10. The frequency converter of claim 8, further comprising a capacitive device connected in parallel between said positive terminal and said negative terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221128840.2U CN217486381U (en) | 2022-05-05 | 2022-05-05 | Filter device and frequency converter |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202221128840.2U CN217486381U (en) | 2022-05-05 | 2022-05-05 | Filter device and frequency converter |
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| CN217486381U true CN217486381U (en) | 2022-09-23 |
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| CN202221128840.2U Active CN217486381U (en) | 2022-05-05 | 2022-05-05 | Filter device and frequency converter |
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