CN109617062B - Star point side adjusting circuit for three-phase alternating current load - Google Patents
Star point side adjusting circuit for three-phase alternating current load Download PDFInfo
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- CN109617062B CN109617062B CN201811601880.2A CN201811601880A CN109617062B CN 109617062 B CN109617062 B CN 109617062B CN 201811601880 A CN201811601880 A CN 201811601880A CN 109617062 B CN109617062 B CN 109617062B
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
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Abstract
The invention discloses a star point side regulating circuit for a three-phase alternating current load, which is used for regulating the current of the three-phase load circuit, and comprises the following components: the three electric signal sampling circuits are respectively used for being connected with the star point side of the three-phase load circuit to obtain standard electric signals on the three-phase load circuit; the control circuit is connected with the three electric signal sampling circuits and respectively outputs three trigger pulse signals according to the standard electric signals on the three-phase load circuit; and one ends of the three trigger driving circuits are connected with the control circuit, the other ends of the three trigger driving circuits are respectively connected with the three electric signal sampling circuits, and the control circuit controls the trigger driving circuits to adjust the current on the corresponding load circuits according to trigger pulse signals output by the electric signal sampling circuits. The invention connects the trigger drive circuit to the star point side of the load circuit to adjust the current of the load circuit and reduce the impact damage of the power grid harmonic wave to the trigger drive circuit under the working state.
Description
Technical Field
The invention relates to the field of load current regulation, in particular to a star point side regulating circuit for a three-phase alternating current load.
Background
Along with the development of industry, the power system accidents caused by harmonic waves in the power system are more and more serious, obviously, the application of related industrial load tests is more and more extensive, especially the starting of a high-power motor, the current power regulation method of the three-phase high-voltage alternating-current high-power load generally adopts the mode that each phase of load circuit is divided into multiple paths, a plurality of contactors (high-voltage vacuum contactors) are adopted to work in parallel, the switching control is carried out according to the required load power, the load is switched by the disconnection and the pull-in of the loading contactors, and then the pull-in of the plurality of contactors needs to be accumulated in a step mode to achieve the required load power; secondly, the starting scheme of the high-power motor is that a control regulating device (thyristor) is generally connected between a power grid and a load motor in series, and the thyristor in the connection mode is very easily damaged by power grid harmonic waves or counter electromotive force impact formed by the power grid and the motor under the working state.
Disclosure of Invention
In view of the drawbacks of the prior art, it is an object of the present invention to provide a star point side regulating circuit for a three-phase ac load, which connects a trigger driving circuit to the star point side of a load circuit to regulate the current of the load circuit, thereby reducing the impact damage of the grid harmonics to the trigger driving circuit in the operating state.
In order to achieve the above purposes, the technical scheme adopted by the invention is as follows:
a regulating circuit for a star point side of a three-phase alternating current load for regulating the current of the three-phase load circuit, the regulating circuit comprising:
the three electric signal sampling circuits are respectively used for being connected with the star point side of the three-phase load circuit to obtain standard electric signals on the three-phase load circuit;
the control circuit is connected with the three electric signal sampling circuits and respectively outputs three trigger pulse signals according to the standard electric signals on the three-phase load circuit;
and one ends of the three trigger driving circuits are connected with the control circuit, the other ends of the three trigger driving circuits are respectively connected with the three electric signal sampling circuits, and the control circuit controls the trigger driving circuits to adjust the current on the corresponding load circuits according to trigger pulse signals output by the electric signal sampling circuits.
On the basis of the above technical solution, the electrical signal sampling circuit includes:
a voltage transformer TV connected in parallel with the load circuit;
and a current transformer TA connected in series with the load circuit.
On the basis of the above technical solution, the control circuit includes:
and the input end of the singlechip is connected with the three electric signal sampling circuits, and the output end of the singlechip is connected with the three trigger driving circuits.
On the basis of the technical scheme, the trigger driving circuit comprises at least one group of thyristor groups, and each group of thyristor groups comprises;
a first thyristor SCR 1;
a second thyristor SCR2 connected in anti-parallel with the first thyristor SCR 1; and the control electrodes of the first thyristor SCR1 and the second thyristor SCR2 are connected with the control circuit.
On the basis of the above technical solution, the thyristor assembly further includes:
and the primary side of the pulse transformer T is connected with the control circuit, and the secondary side of the pulse transformer T is connected with the control electrodes of the first thyristor SCR1 and the second thyristor SCR 2.
On the basis of the technical scheme, the trigger driving circuit comprises two groups of thyristor groups, and the two groups of thyristor groups are connected in series.
On the basis of the technical scheme, the free anode of the first thyristor SCR1 in the trigger driving circuit is connected with the electric signal sampling circuit, and the free cathode of the first thyristor SCR1 is connected with the free cathodes of the first thyristor SCR1 in the other two trigger driving circuits.
On the basis of the above technical solution, the thyristor assembly further includes:
an RC protection circuit connected in parallel with the first thyristor SCR 1.
On the basis of the technical scheme, the first thyristor SCR1 and the second thyristor SCR2 are both high-voltage-resistant 6500V thyristors.
Compared with the prior art, the invention has the advantages that:
the invention provides a star point side regulating circuit for a three-phase alternating current load, which connects a trigger driving circuit with the star point side of a load circuit so as to regulate the current of the load circuit, can continuously regulate the current flowing through the load, reduces the impact damage of overvoltage formed by harmonic superposition of a power grid to the trigger driving circuit in a working state, and improves the safety and stability of the regulating circuit in the application process; meanwhile, the invention also has the advantages that the current on the load circuit is continuously and linearly regulated from small to large, and the flexibility of the invention meets the working requirements of various load condition tests; secondly, the thyristors are reversely connected in parallel to form a group, and the thyristors can work in the positive and negative directions of the alternating current; furthermore, when the voltage of the load circuit is too high, one thyristor group or more thyristor groups are arranged between the short-circuit end and the feedback end of the trigger driving circuit so as to meet the requirement of the rated voltage.
Drawings
FIG. 1 is a schematic circuit diagram of a star point side regulation circuit for a three-phase AC load in accordance with an embodiment of the present invention;
FIG. 2 is a schematic circuit diagram illustrating the connection of two thyristor sets according to an embodiment of the present invention;
Detailed Description
The technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., 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, but 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 invention. 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 invention, it should 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. It is to be noted that all the figures are exemplary representations. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The present invention will be described in further detail below with reference to specific embodiments and with reference to the attached drawings.
Example 1
Referring to fig. 1, an embodiment of the present invention provides a star point side regulating circuit for a three-phase ac load, for regulating current of the three-phase load circuit, the regulating circuit including:
the three electric signal sampling circuits are respectively used for being connected with the star point side of the three-phase load circuit to obtain standard electric signals on the three-phase load circuit;
the control circuit is connected with the three electric signal sampling circuits and respectively outputs three trigger pulse signals according to the standard electric signals on the three-phase load circuit;
and one ends of the three trigger driving circuits are connected with the control circuit, the other ends of the three trigger driving circuits are respectively connected with the three electric signal sampling circuits, and the control circuit controls the trigger driving circuits to adjust the current on the corresponding load circuits according to trigger pulse signals output by the electric signal sampling circuits.
The embodiment of the invention provides a star point side regulating circuit for a three-phase alternating current load, which is characterized in that a trigger driving circuit is connected to the star point side of a load circuit to regulate the current of the load circuit, so that the impact damage of power grid harmonic waves to the trigger driving circuit in a working state is reduced.
In the following, one of the three-phase alternating currents is added for explanation.
The electric signal sampling circuit comprises a voltage transformer TV and a current transformer TA; the voltage transformer TV is connected with a load circuit in parallel; the current transformer TA is connected in series with the load circuit. The voltage transformer TV is connected in parallel to the load circuit and used for acquiring the voltage of the load circuit and converting the voltage into a small voltage; the current transformer TA is connected in series with the load circuit and is used for acquiring the current of the load circuit and converting the current into small current; the standard electrical signal includes the small voltage and the small current.
Furthermore, the control circuit comprises a single chip microcomputer, the input end of the single chip microcomputer is connected with the three electric signal sampling circuits, and the output end of the single chip microcomputer is connected with the three trigger driving circuits. And the single chip microcomputer outputs a trigger pulse signal according to the standard electric signals acquired by the voltage transformer TV and the current transformer TA.
As a preferred solution of the embodiment of the present invention, the trigger driving circuit includes at least one thyristor set; the thyristor assembly comprises a first thyristor SCR1 and a second thyristor SCR 2; the second thyristor SCR2 is connected in anti-parallel with the first thyristor SCR 1; and the control electrodes of the first thyristor SCR1 and the second thyristor SCR2 are connected with the control circuit. And an RC protection circuit is connected in parallel to the first thyristor SCR 1. Specifically, the first thyristor SCR1 and the second thyristor SCR2 are both high-voltage 6500V thyristors.
The first thyristor SCR1 and the second thyristor SCR2 which are connected in parallel in an inverted mode can effectively control alternating current and are not limited by the direction of the alternating current, the thyristor group receives trigger pulse signals output by a singlechip in the control circuit, and the trigger phase shift angle of the thyristor is changed to achieve the functions of turning off, turning on and adjusting current, so that the purpose of controlling and adjusting the current of a load loop is achieved.
Further, the thyristor group further comprises a pulse transformer T, a primary side of which is connected with the control circuit, and a secondary side of which is connected with control electrodes of the first thyristor SCR1 and the second thyristor SCR 2; the pulse transformer T is an isolation pulse transformer.
In this embodiment, the trigger driving circuit includes a set of thyristors; the thyristor group comprises a first thyristor SCR1, a second thyristor SCR2 and a pulse transformer T; the second thyristor SCR2 is connected in anti-parallel with the first thyristor SCR 1; the control electrodes of the first thyristor SCR1 and the second thyristor SCR2 are connected with the secondary side of the pulse transformer T, and the primary side of the pulse transformer T is connected with the control circuit; the anode of the first thyristor SCR1 is connected to the load circuit through the current transformer TA, and the cathode of the first thyristor SCR1 is connected to the cathodes of the first thyristor SCR1 in the other two trigger driving circuits.
In this embodiment, since the operating voltage of the thyristor is specified and cannot be satisfied at any operating voltage level, after the voltage of the load circuit is high, the requirement must be satisfied in a series mode of the thyristor, and the trigger driving circuit includes two groups of thyristor groups, and the two groups of thyristor groups are connected in series. The free anode of the first thyristor SCR1 in the trigger driving circuit is connected with the electric signal sampling circuit, and the free cathode of the first thyristor SCR1 is connected with the free cathodes of the first thyristor SCR1 in the other two trigger driving circuits.
Specifically, as shown in fig. 2, one thyristor group includes a first thyristor SCR1, a second thyristor SCR2, and a pulse transformer T1, and the other thyristor group includes a first thyristor SCR3, a second thyristor SCR4, and a pulse transformer T2; the second thyristor SCR2 is connected in anti-parallel with the first thyristor SCR1, the second thyristor SCR4 is connected in anti-parallel with the first thyristor SCR 3;
the control electrodes of the first thyristor SCR1 and the second thyristor SCR2 are connected with the secondary side of the pulse transformer T1, and the control electrodes of the first thyristor SCR3 and the second thyristor SCR4 are connected with the secondary side of the pulse transformer T2; the primary sides of the pulse transformer T1 and the pulse transformer T2 are connected with the control circuit;
the anode of the first thyristor SCR1 is connected with the load circuit through the current transformer TA, the cathode of the first thyristor SCR1 is connected with the anode of the first thyristor SCR3, and the cathode of the first thyristor SCR3 is connected with the cathodes of the first thyristor SCR3 in the other two trigger drive circuits.
Furthermore, an RC protection circuit is connected in parallel to each of the first thyristor SCR1 and the first thyristor SCR 3.
The load circuit described in the embodiment of the present invention refers to an ac three-phase load circuit, which may be a motor or other inductive load or resistive load, and is not limited to the above embodiment.
The embodiment of the invention provides a star point side regulating circuit for a three-phase alternating current load, which connects a trigger driving circuit to the star point side of a load circuit so as to regulate the current of the load circuit, can continuously regulate the current flowing through the load, reduces the impact damage of overvoltage formed by harmonic superposition of a power grid to the trigger driving circuit in a working state, and improves the safety and stability of the regulating circuit in the application process; meanwhile, the invention also has the advantages that the current on the load circuit is continuously and linearly regulated from small to large, and the flexibility of the invention meets the working requirements of various load condition tests; secondly, the thyristors are reversely connected in parallel to form a group, and the thyristors can work in the positive and negative directions of the alternating current; furthermore, when the voltage of the load circuit is too high, one thyristor group or more thyristor groups are arranged between the short-circuit end and the feedback end of the trigger driving circuit so as to meet the requirement of the rated voltage.
The present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and such modifications and improvements are also considered to be within the scope of the present invention. Those not described in detail in this specification are within the skill of the art.
Claims (5)
1. A regulating circuit for a star point side of a three-phase alternating current load for regulating the current of the three-phase load circuit, the regulating circuit comprising:
the three electric signal sampling circuits are respectively used for being connected with the star point side of the three-phase load circuit to obtain standard electric signals on the three-phase load circuit; the electric signal sampling circuit comprises a voltage transformer TV and a current transformer TA, wherein the voltage transformer TV is connected with the load circuit in parallel, and the current transformer TA is connected with the load circuit in series; the standard electric signal comprises a small voltage and a small current, and the voltage transformer TV is connected in parallel to the load circuit and is used for acquiring the voltage of the load circuit and converting the voltage into the small voltage; the current transformer TA is connected in series with the load circuit and is used for acquiring the current of the load circuit and converting the current into small current;
the control circuit is connected with the three electric signal sampling circuits and respectively outputs three trigger pulse signals according to the standard electric signals on the three-phase load circuit;
the three trigger driving circuits are connected with the control circuit at one end and are respectively connected with the three electric signal sampling circuits at the other end, and the control circuit controls the trigger driving circuits to adjust the current on the corresponding load circuits according to trigger pulse signals output by the standard electric signals;
the trigger driving circuit comprises two groups of thyristor groups which are connected in series; the thyristor group comprises a first thyristor SCR1, a second thyristor SCR2 and a pulse transformer T;
the second thyristor SCR2 is connected in anti-parallel with the first thyristor SCR 1; the control electrodes of the first thyristor SCR1 and the second thyristor SCR2 are connected with the control circuit through the pulse transformer T;
the primary side of the pulse transformer T is connected with the control circuit, and the secondary side of the pulse transformer T is connected with the control electrodes of the first thyristor SCR1 and the second thyristor SCR 2.
2. The star-side regulation circuit for a three-phase alternating current load as claimed in claim 1, wherein the control circuit comprises:
and the input end of the singlechip is connected with the three electric signal sampling circuits, and the output end of the singlechip is connected with the three trigger driving circuits.
3. The star-side regulation circuit for three-phase alternating current loads according to claim 1, wherein the free-state anode of the first thyristor SCR1 in the trigger driving circuit is connected to the electrical signal sampling circuit, and the free-state cathode of the first thyristor SCR1 is connected to the free-state cathodes of the first thyristor SCR1 in the other two trigger driving circuits.
4. The star-side regulation circuit for a three-phase alternating current load as claimed in claim 1, wherein the thyristor group further comprises:
an RC protection circuit connected in parallel with the first thyristor SCR 1.
5. The star-point side regulation circuit for three-phase alternating current loads according to claim 1, wherein the first thyristor SCR1 and the second thyristor SCR2 are high voltage 6500V thyristors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811601880.2A CN109617062B (en) | 2018-12-26 | 2018-12-26 | Star point side adjusting circuit for three-phase alternating current load |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811601880.2A CN109617062B (en) | 2018-12-26 | 2018-12-26 | Star point side adjusting circuit for three-phase alternating current load |
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| Publication Number | Publication Date |
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| CN109617062A CN109617062A (en) | 2019-04-12 |
| CN109617062B true CN109617062B (en) | 2020-08-04 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS5179247A (en) * | 1975-01-06 | 1976-07-10 | Hitachi Ltd | 3 soseigyohoshiki |
| EP2147492A2 (en) * | 2007-05-18 | 2010-01-27 | ABB Technology AG | Static var compensator apparatus |
| CN102097984B (en) * | 2011-02-28 | 2013-11-06 | 大禹电气科技股份有限公司 | Quasi-saturated reactor high-voltage electric motor soft start device |
| CN104362649B (en) * | 2014-11-06 | 2016-07-06 | 国家电网公司 | Thyristor control transformer type controlled reactor DC component restraining device and method |
| CN104935183B (en) * | 2015-06-25 | 2017-11-10 | 西安工程大学 | The voltage transient variation compensation circuit of phase three-wire three transless phase voltage charging |
| CN205753426U (en) * | 2016-06-21 | 2016-11-30 | 湖南工程学院 | Electric power compensation system based on TSC |
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