CN212063830U - Power-on buffer circuit for medium-high voltage 12-pulse rectification and frequency converter - Google Patents
Power-on buffer circuit for medium-high voltage 12-pulse rectification and frequency converter Download PDFInfo
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- CN212063830U CN212063830U CN202020514437.8U CN202020514437U CN212063830U CN 212063830 U CN212063830 U CN 212063830U CN 202020514437 U CN202020514437 U CN 202020514437U CN 212063830 U CN212063830 U CN 212063830U
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Abstract
The utility model belongs to the technical field of electronic circuits, and provides a power-on buffer circuit and a frequency converter for medium-high voltage 12-pulse rectification, wherein the power-on buffer circuit comprises a switch module, a rectification module and a buffer module, and is conducted when a power module is powered on through the switch module, so that the rectification module outputs a direct current signal after rectifying processing is carried out on an alternating current signal output by the power module; the switch module is turned off after the preset time, and the buffer module is used for limiting the current of the direct current signal so as to perform power-on buffering on the 12-pulse rectification circuit. Therefore, the effect of power-on buffering is realized, a transformer is not required to be added, the influence of the transformer on a power-on buffering circuit is avoided, and the working reliability of the frequency converter is greatly improved; meanwhile, the transformer is simple in electrical connection and convenient to install and maintain, and the problems that in the prior art, after a transformer is added, the requirement on safety regulations is high, and the installation and maintenance are troublesome due to the complex circuit structure are solved.
Description
Technical Field
The utility model belongs to the technical field of electronic circuit, especially, relate to an go up electric buffer circuit and converter that is used for middle and high voltage 12 pulse wave commutations.
Background
Because the voltage at two ends of a bus capacitor is zero and the impedance of the bus capacitor is almost 0 omega in the initial power-on state of the frequency converter, a large impact current can be generated in the power-on process to cause the damage of a rectifier bridge and the bus capacitor, and a power-on buffer circuit needs to be added in a main loop of the frequency converter to limit the impact current, so that the rectifier bridge and the bus capacitor are protected.
There are two main approaches to the conventional 12-pulse rectification power-on buffer, as shown in fig. 1 and 2:
fig. 1 shows a conventional snubber scheme, in which two parts of a snubber circuit are connected to an ac input side, respectively, and 4 contactors are required. The scheme has the following defects: 1. the contactor has higher voltage grade and higher cost; 2. the buffer circuit has a complex structure, more electric wires and complex installation and maintenance.
Fig. 2 is the circuit of fig. 1 with the addition of transformers T1 and T2 and the addition of a rectifying circuit for power-on buffering, which uses two medium-high voltage contactors, one low voltage contactor and two transformers. The scheme has the following defects: 1. the two additional transformers need to be subjected to high-low voltage conversion, the safety requirement is high, the field is easy to damage, and the system reliability is influenced; 2. the structure is complicated, and the installation and maintenance are troublesome.
Therefore, the traditional technology has the problems that the requirement on safety regulation is higher after the transformer is added, and the installation and maintenance are troublesome due to the complex circuit structure.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an go up electric buffer circuit and converter for 12 pulse wave commutations of well high pressure, it is higher to aim at solving the conventional art and having the ann rule requirement behind the increase transformer to and the circuit structure complicacy leads to the installation to maintain troublesome problem.
The utility model discloses the first aspect provides a go up electric buffer circuit for well high pressure 12 pulse wave rectifications, with 12 pulse wave rectifier circuit connections, go up electric buffer circuit and include:
the switch module is connected with the power supply module, is configured to be switched on when the power supply module is powered on, and is switched off after preset time;
the rectification module is connected with the switch module and is configured to output a direct current signal after rectifying the alternating current signal output by the power supply module; and
and the buffer module is connected with the rectifying module and the 12 pulse wave rectifying circuit and is configured to limit the current of the direct current signal so as to perform power-on buffering on the 12 pulse wave rectifying circuit.
Preferably, the switch module is realized by a medium-high voltage buffer contactor.
Preferably, the rectifier module is implemented by a rectifier bridge.
Preferably, the buffer module is implemented by using a buffer resistor.
Preferably, the rectifying module includes:
the first rectifying module, the second rectifying module, the third rectifying module and the fourth rectifying module;
the input end of the first rectification module and the output end of the second rectification module are connected with the first output end of the middle-high voltage buffer contactor, the input end of the third rectification module and the output end of the fourth rectification module are connected with the second output end of the middle-high voltage buffer contactor, the output end of the first rectification module and the output end of the third rectification module are used as the first output end of the rectification module, and the input end of the second rectification module and the input end of the fourth rectification module are used as the second output end of the rectification module.
Preferably, the buffer module includes:
a first resistor and a second resistor;
the first end of the first resistor is connected with the output end of the first rectifying module and the output end of the third rectifying module, the second end of the second resistor is connected with the input end of the second rectifying module and the input end of the fourth rectifying module, and the second end of the first resistor and the second end of the second resistor are connected with the 12-pulse rectifying circuit.
Preferably, the first rectifying module, the second rectifying module, the third rectifying module and the fourth rectifying module each include a plurality of diodes connected in series one by one.
The utility model discloses the second aspect provides a frequency converter, include:
12 pulse wave rectifying circuits; and
the power-on buffer circuit is connected to the 12-pulse rectification circuit and configured to perform power-on buffering on the 12-pulse rectification circuit.
Preferably, the 12-pulse rectification circuit 50 includes:
the circuit comprises a first capacitor, a second capacitor and a 12-pulse rectification unit consisting of 12 diodes;
the first end of the first capacitor and the first end of the second capacitor are connected with the 12-pulse rectification unit, and the second end of the first capacitor and the second end of the second capacitor are grounded.
Preferably, the frequency converter further comprises a first main contactor and a second main contactor;
the first main contactor and the second main contactor are connected with the 12-pulse rectification unit, and the first main contactor and the second main contactor are configured to be turned off when the power module is powered on and are turned on after the preset time.
The utility model provides a go up electric buffer circuit and converter for medium and high voltage 12 pulse wave rectification, should go up electric buffer circuit and include switch module, rectifier module and buffer module, switch on when power module is gone up through switch module for the rectifier module carries out rectification processing to the alternating current signal of power module output, exports direct current signal; the switch module is turned off after the preset time, and the buffer module is used for limiting the current of the direct current signal so as to perform power-on buffering on the 12-pulse rectification circuit. Therefore, the effect of power-on buffering is realized, a transformer is not required to be added, the influence of the transformer on a power-on buffering circuit is avoided, and the working reliability of the frequency converter is greatly improved; meanwhile, the transformer is simple in electrical connection and convenient to install and maintain, and the problems that in the prior art, after a transformer is added, the requirement on safety regulations is high, and the installation and maintenance are troublesome due to the complex circuit structure are solved.
Drawings
Fig. 1 is a circuit diagram illustrating an example of a power-up buffer circuit according to the prior art.
Fig. 2 is a circuit diagram illustrating an example of a power-up buffer circuit of an additional transformer according to the prior art.
Fig. 3 is a schematic block diagram of an upper power buffer circuit for medium-high voltage 12-pulse rectification according to an embodiment of the present invention.
Fig. 4 is a circuit diagram of an example of a power-up buffer circuit for medium-high voltage 12-pulse rectification provided in correspondence with fig. 3.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The power-on buffer circuit for medium-high voltage 12-pulse rectification and the frequency converter comprise a switch module, a rectification module and a buffer module, wherein the switch module is conducted when the power module is powered on, so that the rectification module rectifies an alternating current signal output by the power module and outputs a direct current signal; the switch module is turned off after the preset time, and the buffer module is used for limiting the current of the direct current signal so as to perform power-on buffering on the 12-pulse rectification circuit. Therefore, the effect of power-on buffering is realized, a transformer is not required to be added, the influence of the transformer on a power-on buffering circuit is avoided, and the working reliability of the frequency converter is greatly improved; meanwhile, the electric connection is simple, and the installation and maintenance are convenient.
Fig. 3 shows a module structure of a power-on buffer circuit for medium-high voltage 12-pulse rectification according to an embodiment of the present invention, and for convenience of description, only the parts related to this embodiment are shown, which are detailed as follows:
the power-on buffer circuit 40 for medium-high voltage 12-pulse rectification is connected with the 12-pulse rectification circuit 50, and comprises a switch module 10, a rectification module 20 and a buffer module 30.
The switch module 10 is connected to the power module 60, and is configured to be turned on when the power module 60 is powered on, and turned off after a preset time.
The rectifying module 20 is connected to the switching module 10, and configured to output a dc signal after rectifying the ac signal output by the power supply module 60.
The buffer module 30 is connected to the rectifier module 20 and the 12-pulse rectifier circuit 50, and configured to limit the current of the dc signal to perform power-on buffering on the 12-pulse rectifier circuit 50.
As an embodiment of the present invention, the switch module 10 is implemented by a middle-high voltage buffer contactor KM 1.
As an embodiment of the present invention, the above-mentioned rectifier module 20 is implemented by a rectifier bridge.
As an embodiment of the present invention, the above-mentioned buffer module 30 is implemented by using a buffer resistor.
Therefore, the power-on buffer circuit still adopts the rectifier module 20, but a voltage transformation module (transformer) is cancelled, only 1 medium-high voltage buffer contactor is needed, the influence of the transformer on the power-on buffer circuit is avoided, and the working reliability of the frequency converter is greatly improved; meanwhile, the electric connection is simple, and the installation and maintenance are convenient.
It should be understood that the preset time may be set according to actual needs, and the preset time is also the power-on buffer time.
Fig. 4 shows an exemplary circuit of a power-up buffer circuit for medium-high voltage 12-pulse rectification provided corresponding to fig. 3, and for convenience of illustration, only the parts related to the present embodiment are shown, and detailed as follows:
as an embodiment of the present invention, the above-mentioned rectifier module 20 includes a first rectifier module, a second rectifier module, a third rectifier module and a fourth rectifier module.
The input end of the first rectifying module and the output end of the second rectifying module are connected with the first output end of the medium-high voltage buffer contactor, the input end of the third rectifying module and the output end of the fourth rectifying module are connected with the second output end of the medium-high voltage buffer contactor, the output end of the first rectifying module and the output end of the third rectifying module are used as the first output end of the rectifying module 20, and the input end of the second rectifying module and the input end of the fourth rectifying module are used as the second output end of the rectifying module 20.
As an embodiment of the present invention, the buffer module 30 includes a first resistor R1 and a second resistor.
The first end of the first resistor R1 is connected to the output end of the first rectifying module and the output end of the third rectifying module, the second end of the second resistor R2 is connected to the input end of the second rectifying module and the input end of the fourth rectifying module, and the second ends of the first resistor R1 and the second resistor R2 are connected to the 12-pulse rectifying circuit 50.
Specifically, the first, second, third and fourth rectifying modules each include a plurality of diodes connected in series one by one (as represented in fig. 4 by D1 … D1n, D2 … D2n, D3 … D3n, D4 … D4 n).
Illustratively, the power module 60 is a three-phase ac medium-high voltage power supply, and can be commonly used as an input power supply of the 12-pulse rectifier circuit 50, the three-phase ac medium-high voltage power supply is connected to the rectifier module 20 through the medium-high voltage buffer contactor KM1, the other phase is directly connected to the intermediate potential of the bus capacitor, and the first resistor R1 and the second resistor R2 are buffer resistors. When the frequency converter is powered on, the medium-high voltage buffer contactor KM1 is attracted, and the power supply charges the bus capacitor through the medium-high voltage buffer contactor KM1, the rectifying module 20 and the buffer resistor.
When a main loop of the frequency converter is electrified, the first main contactor KM2 and the second main contactor KM3 are disconnected, a frequency converter control system sends a pull-in control signal of the buffer contactor, and the medium-high voltage buffer contactor KM1 is pulled in. The three-phase alternating-current medium-high voltage power supply is connected to the input side of the rectifier module 20, the output side of the rectifier module 20 is respectively connected to DC +, DC-of a bus capacitor (a first capacitor C1 and a second capacitor C2) through buffer resistors (a first resistor R1 and a second resistor R2), W-phase is directly connected to N of the bus capacitor, the three-phase alternating-current medium-high voltage power supply charges the bus capacitor (the first capacitor C1 and the second capacitor C2) through the rectifier module 20, when the bus voltage reaches the design voltage, the frequency converter control system sends a main contactor pull-in control signal, a first main contactor KM2 and a second main contactor KM3 in a main circuit pull in, the frequency converter main circuit is connected to the three-phase medium-high voltage power supply, meanwhile, the medium-high voltage buffer contactor KM1 is controlled to be disconnected.
The utility model also provides a frequency converter, include:
a 12-pulse rectifier circuit 50; and
the power-on buffer circuit 40 as described above is connected to the 12-pulse rectifier circuit 50, and is configured to power-on buffer the 12-pulse rectifier circuit 50.
It should be noted that, the frequency converter is provided with the 12-pulse rectification circuit 50 on the basis of the power-up buffer circuit 40, so that the functional description and the principle description of the switch module 10, the rectification module 20 and the buffer module 30 in the power-up buffer circuit 40 can refer to the embodiments of fig. 3 to 4, and details are not repeated herein.
In an embodiment of the present invention, the 12-pulse rectification circuit 50 includes a first capacitor C1, a second capacitor C2, and a 12-pulse rectification unit 501 composed of 12 diodes.
The first terminal of the first capacitor C1 and the first terminal of the second capacitor C2 are connected to the 12-pulse rectification unit 501, and the second terminal of the first capacitor C1 and the second terminal of the second capacitor C2 are connected to ground.
The 12-pulse rectification unit is realized by adopting an existing circuit structure.
As an embodiment of the present invention, the frequency converter further includes a first main contactor KM2 and a second main contactor KM 3.
The first main contactor KM2 and the second main contactor KM3 are connected to the 12-pulse rectification unit 501, and the first main contactor KM2 and the second main contactor KM3 are configured to be turned off when the power module 60 is powered on, and are turned on after a preset time.
Specifically, the power-on buffer circuit and the frequency converter for medium-high voltage 12-pulse rectification have the following advantages:
1. the power-on buffer circuit does not need a transformer, so that the phenomenon of field damage of the transformer is avoided;
2. the input of the power-on buffer circuit is connected with a power supply, and the output of the power-on buffer circuit is connected with the high, low and middle potentials of the bus capacitor, so that no other electrical connection exists, and the installation and maintenance are convenient;
3. the power-on buffer circuit is independent of the main circuit of the frequency converter, so that impact on a rectifier bridge of the main circuit during power-on is avoided, and the reliability of the frequency converter is improved.
The working principle of the power-up buffer circuit and the frequency converter for medium-high voltage 12-pulse rectification is described below with reference to fig. 3 to 4 as follows:
use AC 3PH 3.3kV 1.5MW high pressure three-level converter as an example, its upper electric buffer circuit adopts the utility model discloses the scheme.
The frequency converter main circuit comprises a first main contactor KM2, a second main contactor KM3, a 12-pulse rectification unit 501 and a bus capacitor (a first capacitor C1 and a second capacitor C2); the upper electric buffer circuit consists of a medium-high voltage buffer contactor KM1, rectifier diodes D1-D4 and buffer resistors (a first resistor R1 and a second resistor R2).
After the frequency converter is powered on, the input voltage of a 12-pulse rectification unit 501 in the main circuit is an AC 3PH 1.8kV power supply, a middle-high voltage buffer contactor KM1 is closed, the front end of the middle-high voltage buffer contactor KM1 is connected with the 1.8kV power supply, bus capacitors (a first capacitor C1 and a second capacitor C2) are charged through buffer resistors (a first resistor R1 and a second resistor R2) after being rectified by a diode, when the voltage of the bus capacitors reaches a design value, the first main contactor KM2 and the second main contactor KM3 are attracted, and the middle-high voltage buffer contactor KM1 is disconnected;
and when the power-on buffering time is reached, the 3.3kV power electricity is connected to the main circuit of the frequency converter, the medium-high voltage buffering contactor KM1 is disconnected, and the power-on buffering process is finished.
To sum up, the embodiment of the present invention provides a power-on buffer circuit and a frequency converter for medium-high voltage 12-pulse rectification, wherein the power-on buffer circuit includes a switch module, a rectification module and a buffer module, and is conducted when a power module is powered on through the switch module, so that the rectification module rectifies an ac signal output by the power module and outputs a dc signal; the switch module is turned off after the preset time, and the buffer module is used for limiting the current of the direct current signal so as to perform power-on buffering on the 12-pulse rectification circuit. Therefore, the effect of power-on buffering is realized, a transformer is not required to be added, the influence of the transformer on a power-on buffering circuit is avoided, and the working reliability of the frequency converter is greatly improved; meanwhile, the transformer is simple in electrical connection and convenient to install and maintain, and the problems that in the prior art, after a transformer is added, the requirement on safety regulations is high, and the installation and maintenance are troublesome due to the complex circuit structure are solved.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A power-on buffer circuit for medium-high voltage 12-pulse rectification, which is connected with a 12-pulse rectification circuit, is characterized by comprising:
the switch module is connected with the power supply module, is configured to be switched on when the power supply module is powered on, and is switched off after preset time;
the rectification module is connected with the switch module and is configured to output a direct current signal after rectifying the alternating current signal output by the power supply module; and
and the buffer module is connected with the rectifying module and the 12 pulse wave rectifying circuit and is configured to limit the current of the direct current signal so as to perform power-on buffering on the 12 pulse wave rectifying circuit.
2. The power-on buffer circuit according to claim 1, wherein the switch module is implemented using a medium-high voltage buffer contactor.
3. The power-on buffer circuit according to claim 1, wherein the rectifying module is implemented using a rectifying bridge.
4. The power-on buffer circuit of claim 1, wherein the buffer module is implemented using a buffer resistor.
5. The power-on buffer circuit of claim 2, wherein the rectification module comprises:
the first rectifying module, the second rectifying module, the third rectifying module and the fourth rectifying module;
the input end of the first rectification module and the output end of the second rectification module are connected with the first output end of the middle-high voltage buffer contactor, the input end of the third rectification module and the output end of the fourth rectification module are connected with the second output end of the middle-high voltage buffer contactor, the output end of the first rectification module and the output end of the third rectification module are used as the first output end of the rectification module, and the input end of the second rectification module and the input end of the fourth rectification module are used as the second output end of the rectification module.
6. The power-up buffer circuit of claim 5, wherein the buffer module comprises:
a first resistor and a second resistor;
the first end of the first resistor is connected with the output end of the first rectifying module and the output end of the third rectifying module, the second end of the second resistor is connected with the input end of the second rectifying module and the input end of the fourth rectifying module, and the second end of the first resistor and the second end of the second resistor are connected with the 12-pulse rectifying circuit.
7. The power-on buffer circuit of claim 5, wherein the first, second, third, and fourth rectification modules each comprise a plurality of diodes connected in series one to one.
8. A frequency converter, comprising:
12 pulse wave rectifying circuits; and
the power-on buffer circuit as claimed in any of claims 1-7, coupled to the 12-pulse rectification circuit, and configured to power-on buffer the 12-pulse rectification circuit.
9. The frequency converter according to claim 8, wherein said 12-pulse rectification circuit comprises:
the circuit comprises a first capacitor, a second capacitor and a 12-pulse rectification unit consisting of 12 diodes;
the first end of the first capacitor and the first end of the second capacitor are connected with the 12-pulse rectification unit, and the second end of the first capacitor and the second end of the second capacitor are grounded.
10. The frequency converter of claim 9, further comprising:
a first main contactor and a second main contactor;
the first main contactor and the second main contactor are connected with the 12-pulse rectification unit, and the first main contactor and the second main contactor are configured to be turned off when the power module is powered on and are turned on after the preset time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020514437.8U CN212063830U (en) | 2020-04-09 | 2020-04-09 | Power-on buffer circuit for medium-high voltage 12-pulse rectification and frequency converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020514437.8U CN212063830U (en) | 2020-04-09 | 2020-04-09 | Power-on buffer circuit for medium-high voltage 12-pulse rectification and frequency converter |
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| Publication Number | Publication Date |
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| CN212063830U true CN212063830U (en) | 2020-12-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202020514437.8U Active CN212063830U (en) | 2020-04-09 | 2020-04-09 | Power-on buffer circuit for medium-high voltage 12-pulse rectification and frequency converter |
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| CN (1) | CN212063830U (en) |
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