CN209746019U - Voltage sag generating unit and voltage sag generator - Google Patents
Voltage sag generating unit and voltage sag generator Download PDFInfo
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- CN209746019U CN209746019U CN201920371922.1U CN201920371922U CN209746019U CN 209746019 U CN209746019 U CN 209746019U CN 201920371922 U CN201920371922 U CN 201920371922U CN 209746019 U CN209746019 U CN 209746019U
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Abstract
The application discloses voltage sag generating unit includes: the three-level PWM rectifier module, the bidirectional DC-DC conversion module and the three-level inversion module; the bidirectional DC-DC conversion module comprises a first bidirectional DC-DC converter and a second bidirectional DC-DC converter which are both in an isolation type; the negative electrode of the primary side of the first bidirectional DC-DC converter is connected with the positive electrode of the primary side of the second bidirectional DC-DC converter to form a zero-level end of the primary side of the bidirectional DC-DC conversion module; the negative electrode of the secondary side of the first bidirectional DC-DC converter is connected with the positive electrode of the secondary side of the second bidirectional DC-DC converter to form a neutral point end of the secondary side of the bidirectional DC-DC conversion module; the primary side of the bidirectional DC-DC conversion module is connected with the three-level PWM rectification module, and the secondary side of the bidirectional DC-DC conversion module is connected with the three-level inversion module; the voltage sag generator solves the technical problems that the existing high-power voltage sag generator is heavy and large in size, and the single-phase voltage sag test is small in size. The application also discloses a voltage sag generator.
Description
Technical Field
The application relates to the technical field of electric power tests, in particular to a voltage sag generating unit and a voltage sag generator.
background
With the development of electric power, the power quality problem is also gradually receiving attention, wherein the voltage sag is an important part of the power quality problem. The voltage sag is a condition that the effective value of the output voltage suddenly drops in a certain time period and is finally recovered to the normal output voltage after being maintained for a certain time period. Obviously, once this happens, it will have an impact and impact on the normal operation of the power equipment. For this reason, it is necessary to perform a simulation test of voltage sag on the electric power equipment.
The existing high-power voltage sag generator is generally provided with a power frequency transformer on a rectification side to form fault isolation, but the whole generator becomes heavy due to the addition of the power frequency transformer, and when some equipment is tested, even the equipment cannot enter an industrial elevator due to too large volume, the test process is very inconvenient. In addition, the existing generator is usually designed for three-phase three-wire system test, and some devices have the requirement for single-phase or two-phase voltage sag test, so that even if only single-phase voltage sag test is planned in a certain operation, the generator designed for three-phase three-wire system is only heavy and can be transported to the field completely, a lot of manpower is consumed, and the method is a small-topic practice.
SUMMERY OF THE UTILITY MODEL
The application provides a voltage sag generating unit and a voltage sag generator, and solves the technical problems that the conventional high-power voltage sag generator is heavy and large in size, and the single-phase voltage sag test is small in size.
In view of the above, a first aspect of the present application provides a voltage sag generating unit, including: the three-level PWM rectifier module, the bidirectional DC-DC conversion module and the three-level inversion module;
The bidirectional DC-DC conversion module comprises a first bidirectional DC-DC converter and a second bidirectional DC-DC converter which are both in an isolated type;
the negative electrode of the primary side of the first bidirectional DC-DC converter is connected with the positive electrode of the primary side of the second bidirectional DC-DC converter to form a zero-level end of the primary side of the bidirectional DC-DC conversion module;
The negative electrode of the secondary side of the first bidirectional DC-DC converter is connected with the positive electrode of the secondary side of the second bidirectional DC-DC converter to form a neutral point end of the secondary side of the bidirectional DC-DC conversion module;
The primary side of the bidirectional DC-DC conversion module is connected with the three-level PWM rectification module, and the secondary side of the bidirectional DC-DC conversion module is connected with the three-level inversion module.
Preferably, a high-frequency transformer for isolation is arranged in each of the first bidirectional DC-DC converter and the second bidirectional DC-DC converter.
Preferably, the first bidirectional DC-DC converter and the second bidirectional DC-DC converter are two active full-bridge bidirectional DC-DC converters.
Preferably, the three-level inverter module is a three-level half-bridge inverter module.
Preferably, the three-level half-bridge inverter module comprises in particular a three-level diode-clamped inverter.
preferably, the switching devices in the three-level PWM rectification module, the bidirectional DC-DC conversion module, and the three-level inversion module are all IGBTs.
preferably, the three-level inverter module specifically includes three bidirectional DC-DC conversion modules and three-level inverter modules;
The three-level PWM rectification module is respectively connected with the primary sides of the three bidirectional DC-DC conversion modules, and the secondary side of each bidirectional DC-DC conversion module is connected with one three-level inversion module.
A second aspect of the present application provides a voltage sag generator comprising a plurality of any one of the voltage sag generating units described above in relation to the first aspect;
The voltage sag generating units are connected in parallel.
preferably, four voltage sag generating units are specifically included.
According to the technical scheme, the method has the following advantages:
The application provides a voltage sag generating unit, which comprises a three-level PWM rectifying module, a bidirectional DC-DC conversion module and a three-level inversion module. The bidirectional DC-DC conversion module comprises a first bidirectional DC-DC converter and a second bidirectional DC-DC converter which are both in an isolation type. Therefore, the bidirectional DC-DC converter is adopted to replace a power frequency transformer in the existing high-power voltage sag generator, so that the middle stage can adopt a modular design, and the rear stage can also adopt a modular design, thereby greatly reducing the volume and the weight of the voltage sag generator.
Moreover, the voltage sag generating unit provided by the application is designed by taking single-phase voltage sag testing requirements as a unit, if single-phase voltage sag testing is only required, wiring testing can be performed only by transporting a three-level PWM (pulse width modulation) rectifying module, a bidirectional DC-DC (direct current-direct current) conversion module and a three-level inverter module to the field, and the whole set of generators for the three-phase voltage sag testing does not need to be moved originally, so that the flexibility of the voltage sag generators in adapting to different requirements is greatly improved.
on the other hand, this application provides voltage sag generating unit, and preceding stage, intermediate level all correspond three levels with the back level, and wherein the back level can set up neutral point end, uses after the combination through a plurality of voltage sag generating unit, can satisfy the wiring requirement of three-phase four-wire system, therefore has also improved the ability of the different test demands of adaptation of generator.
drawings
Fig. 1 is a schematic structural diagram of a voltage sag generating unit in an implementation manner provided in the present application;
fig. 2 is a schematic structural diagram of a bidirectional DC-DC conversion module in an implementation manner provided in the present application;
Fig. 3 is a schematic structural diagram of a three-level inverter module in an implementation manner provided in the present application;
Fig. 4 is a schematic structural diagram of a three-level PWM rectifier according to an implementation manner provided in the present application;
fig. 5 is a schematic structural diagram of a voltage sag generating unit in another implementation manner provided in the present application;
Reference numerals: the three-level PWM rectifier module 1, the bidirectional DC-DC conversion module 2 and the three-level inversion module 3.
Detailed Description
The technical solutions of the present application will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
The existing high-power voltage sag generator is generally provided with a power frequency transformer, the whole generator becomes heavy due to the addition of the power frequency transformer, and when some equipment is tested, even the industrial elevator cannot be entered due to too large volume, the test process is very inconvenient.
on the other hand, the difference of the test sensitivity vectors for different devices results in different degrees of voltage sag generated by the device under test to the voltage sag generator, such as: for an ac contactor, besides the sag amplitude and the sag duration, the phase jump and the sag start point have a serious influence on the ac contactor, and for a variable frequency speed control system, besides the sag amplitude and the sag duration, different types of voltage sag classifications, such as three-phase, two-phase, and single-phase faults, are also required. The existing generators are designed for three-phase voltage sag tests, and the generators are small in size when used for single-phase voltage sag tests; in addition, the existing generator is designed only for a three-phase three-wire system, and equipment with a three-phase four-wire system test requirement is difficult to meet.
The application provides a voltage sag generating unit, includes: the three-level PWM rectifier module 1, the bidirectional DC-DC conversion module 2 and the three-level inversion module 3. The bidirectional DC-DC conversion module 2 includes a first bidirectional DC-DC converter and a second bidirectional DC-DC converter, both of which are isolated.
In order to connect with the front stage and the rear stage of the three levels, the bidirectional DC-DC conversion module 2 as the middle stage, the cathode of the primary side of the first bidirectional DC-DC converter may be connected with the anode of the primary side of the second bidirectional DC-DC converter, and a terminal may be disposed at the connection, where the terminal is the zero-level end of the bidirectional DC-DC conversion module 2 on the rectification side.
Correspondingly, the secondary cathode of the first bidirectional DC-DC converter may be connected to the secondary anode of the second bidirectional DC-DC converter, and a terminal is also led out from the connection as a neutral point end of the bidirectional DC-DC conversion module 2 on the inverting side.
at this time, the primary side of the bidirectional DC-DC conversion module 2 may be connected to the three-level PWM rectification module 1, and the secondary side of the bidirectional DC-DC conversion module 2 may be connected to the three-level inverter module 3. Specifically, referring to fig. 1, on the rectification side, the high level end of the bidirectional DC-DC conversion module 2 is connected to the high level end of the three-level PWM rectification module 1, the zero level end of the bidirectional DC-DC conversion module 2 is connected to the zero level end of the three-level PWM rectification module 1, and the low level end of the bidirectional DC-DC conversion module 2 is connected to the low level end of the three-level PWM rectification module 1. On the inversion side, the positive terminal of the bidirectional DC-DC conversion module 2 is connected with the positive terminal of the three-level inversion module 3, the neutral point terminal of the bidirectional DC-DC conversion module 2 is connected with the neutral point terminal of the three-level PWM rectification module 1, and the negative terminal of the bidirectional DC-DC conversion module 2 is connected with the negative terminal of the three-level PWM rectification module 1.
it can be understood that the front stage, the middle stage and the rear stage of the voltage sag generating unit provided by the application all adopt a three-level structure, and harmonic components of output waveforms can be effectively reduced.
the first bidirectional DC-DC converter and the second bidirectional DC-DC converter in the bidirectional DC-DC conversion module 2 are both isolated converters, and specifically, a high-frequency transformer for isolation is arranged therein.
The isolated bidirectional DC-DC converter has various types, the application provides a preferable double-active full-bridge bidirectional DC-DC converter, the first bidirectional DC-DC converter and the second bidirectional DC-DC converter both adopt double-active full-bridge bidirectional DC-DC converters, and the first bidirectional DC-DC converter and the second bidirectional DC-DC converter are connected to form the bidirectional DC-DC conversion module 2. The specific circuit structure of the bidirectional DC-DC conversion module 2 can be seen in fig. 2.
The three-level inverter module 3 also has a plurality of inverter circuits that can be used, and the present application provides a preferred implementation manner, and a three-level half-bridge inverter circuit, specifically a three-level diode clamp inverter, is adopted, and a specific circuit structure thereof can be seen in fig. 3.
The circuit structure of the three-level PWM rectifier can be seen in fig. 4.
The switching devices in the three-level PWM rectification module 1, the bidirectional DC-DC conversion module 2 and the three-level inversion module 3 can uniformly select the IGBT, so that the circuit parameters can be conveniently designed in a standardized manner, and the manufacturing cost is reduced.
Referring to fig. 1 to 4, after being cascaded, the three-level PWM rectification module 1, the bidirectional DC-DC conversion module 2, and the three-level inverter module 3 may form a generating unit suitable for a single-phase voltage sag test. When the three-phase voltage sag test is required, three bidirectional DC-DC conversion modules 2 and three-level inverter modules 3 can be arranged. As shown in fig. 5, the three-level PWM rectification module 1 is connected to the primary sides of three bidirectional DC-DC conversion modules 2, and the secondary side of each bidirectional DC-DC conversion module 2 is connected to one three-level inverter module 3.
the generating unit formed by the arrangement can adapt to the requirement of three-phase voltage sag test, and the three-level inverter module 3 at the rear stage has a neutral point end, so that the working requirement of three-phase three-wire/three-phase four-wire can be met. On the other hand, the middle stage comprises six bidirectional DC-DC converters, the six bidirectional DC-DC converters are connected in parallel and can equally divide the output power of the rectifying part, so that the current loaded on the power switch tube is greatly reduced, the requirement on the power switch tube is reduced, the size of the middle stage module can be reduced, and the power density can be obviously improved.
The above is a detailed description of the voltage sag generating unit provided in the present application. The voltage sag generating unit provided by the application adopts the bidirectional DC-DC converter to replace a power frequency transformer in the existing high-power voltage sag generator, so that the middle stage can adopt a modular design, and the rear stage can also adopt a modular design, thereby greatly reducing the volume and weight of the voltage sag generator. Meanwhile, after modularization, the adaptability of the voltage sag generating unit to different test requirements is greatly improved.
For example, three bidirectional DC-DC conversion modules 2 and three-level inversion modules 3 may be provided to combine a generating unit suitable for a three-phase voltage sag test, and the requirements of a three-phase three-wire/three-phase four-wire can be met. For example, when a single-phase voltage sag test is performed, a wiring test can be performed by only transporting one three-level PWM rectification module 1, one bidirectional DC-DC conversion module 2, and one three-level inverter module 3 to the field, and the entire set of generators for the three-phase voltage sag test does not need to be transported as before.
The application also provides a voltage sag generator to accommodate voltage sag tests that typically require high power output. Specifically, the voltage sag generator provided by the present application includes a plurality of voltage sag generating units in any of the above implementation manners, and the plurality of voltage sag generating units are connected in parallel.
After the voltage sag generating units are connected in parallel, the output power of the generator can be improved. For example, for a single voltage sag generator, the output power of the generator can reach 50KVA, but after four voltage sag generators are connected in parallel, the output power of the generator can reach 200 KVA.
Of course, it should be noted that the superposition of the output power may be applied to single-phase voltage sag or two-phase and three-phase voltage sag tests, depending on the selected voltage sag generating unit. For example, when a plurality of generating units (i.e., voltage sag generating units formed by cascading a three-level PWM rectifying module 1, a bidirectional DC-DC converting module 2, and a three-level inverting module 3) suitable for single-phase voltage sag testing are selected to be connected in parallel, the voltage sag generator is suitable for high-power single-phase voltage sag testing. When a plurality of generating units (namely, voltage sag generating units formed by cascading a three-level PWM rectifying module 1, three bidirectional DC-DC conversion modules 2 and three-level inversion modules 3) suitable for three-phase voltage sag testing are selected to be connected in parallel, the voltage sag generator can be suitable for high-power three-phase voltage sag testing.
The terms "first," "second," "third," "fourth," and the like in the description of the application and the above-described figures, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be understood that in the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" for describing an association relationship of associated objects, indicating that there may be three relationships, e.g., "a and/or B" may indicate: only A, only B and both A and B are present, wherein A and B may be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (9)
1. a voltage sag generating unit, comprising: the three-level PWM rectifier module, the bidirectional DC-DC conversion module and the three-level inversion module;
the bidirectional DC-DC conversion module comprises a first bidirectional DC-DC converter and a second bidirectional DC-DC converter which are both in an isolated type;
The negative electrode of the primary side of the first bidirectional DC-DC converter is connected with the positive electrode of the primary side of the second bidirectional DC-DC converter to form a zero-level end of the primary side of the bidirectional DC-DC conversion module;
the negative electrode of the secondary side of the first bidirectional DC-DC converter is connected with the positive electrode of the secondary side of the second bidirectional DC-DC converter to form a neutral point end of the secondary side of the bidirectional DC-DC conversion module;
The primary side of the bidirectional DC-DC conversion module is connected with the three-level PWM rectification module, and the secondary side of the bidirectional DC-DC conversion module is connected with the three-level inversion module.
2. The voltage sag generating unit according to claim 1, wherein a high-frequency transformer for isolation is provided in each of the first and second bidirectional DC-DC converters.
3. The voltage sag generating unit according to claim 2, wherein the first and second bidirectional DC-DC converters are in particular dual-active full-bridge bidirectional DC-DC converters.
4. Voltage sag generating unit according to claim 1, wherein the three-level inverter module is in particular a three-level half-bridge inverter module.
5. The voltage sag generating unit according to claim 3, wherein the tri-level half-bridge inverter module comprises in particular a tri-level diode-clamped inverter.
6. The voltage sag generating unit according to claim 1, wherein the switching devices in the three-level PWM rectifying module, the bidirectional DC-DC converting module, and the three-level inverting module are IGBTs.
7. The voltage sag generating unit according to any one of claims 1 to 6, further comprising three bidirectional DC-DC converting modules and three-level inverting modules;
The three-level PWM rectification module is respectively connected with the primary sides of the three bidirectional DC-DC conversion modules, and the secondary side of each bidirectional DC-DC conversion module is connected with one three-level inversion module.
8. A voltage sag generator comprising a plurality of voltage sag generating units according to any one of claims 1 to 7;
The voltage sag generating units are connected in parallel.
9. The voltage sag generator according to claim 8, comprising in particular four voltage sag generating units.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920371922.1U CN209746019U (en) | 2019-03-22 | 2019-03-22 | Voltage sag generating unit and voltage sag generator |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920371922.1U CN209746019U (en) | 2019-03-22 | 2019-03-22 | Voltage sag generating unit and voltage sag generator |
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| CN209746019U true CN209746019U (en) | 2019-12-06 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109738678A (en) * | 2019-03-22 | 2019-05-10 | 广东电网有限责任公司 | A kind of voltage dip generating unit and voltage dip generator |
| CN109738678B (en) * | 2019-03-22 | 2024-06-04 | 广东电网有限责任公司 | Voltage sag generating unit and voltage sag generator |
-
2019
- 2019-03-22 CN CN201920371922.1U patent/CN209746019U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109738678A (en) * | 2019-03-22 | 2019-05-10 | 广东电网有限责任公司 | A kind of voltage dip generating unit and voltage dip generator |
| CN109738678B (en) * | 2019-03-22 | 2024-06-04 | 广东电网有限责任公司 | Voltage sag generating unit and voltage sag generator |
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