CN201210442Y - Novel high resistance self-coupled transformer - Google Patents

Abstract

The utility model relates to the technical field of transformers, in particular to an autotransformer. An iron core of the transformer comprises a main iron core and a secondary iron core, wherein the main iron core is a main loop of a main magnetic flux and adopts a structure of opening air gaps on a core column and a transverse yoke; the secondary iron core is a main loop of a leakage magnetic flux and has the air gaps on the core column according to the strength of short-circuit impedance; and a winding is divided into a common winding and a serial winding, wherein one winding is only wound on the main iron core, while the other winding is wound on both the main iron core and the secondary iron core. The autotransformer uses the secondary iron core as the main loop of the leakage magnetic flux to improve short-circuit impedance and can be adjusted randomly; and through adjusting the air gaps of the secondary iron core, the strength of the leakage magnetic flux can be changed, so as to change leakage inductance, namely change the short-circuit impedance. Through adjusting the air gaps of the main iron yoke, the idling current of the transformer can be adjusted, the balance degree of three-phase output voltage also can be adjusted to reach 0.25 percent; and the autotransformer has a simple structure and low manufacturing cost.

Description

A kind of novel high impedance autotransformer

Technical field:

The utility model relates to the transformer technology field, refers in particular to a kind of autotransformer.

Background technology:

As everyone knows, because its coil volume of autotransformer is less than rated capacity, under the situation that rated capacity equates, the autotransformer volume is little, in light weight, save material, cost is lower; Employed effective material (silicon steel sheet and copper cash) reduces, and iron loss, copper loss is reduced, so efficient is higher; Because volume is little in light weight, institute is so that transport, install.But for a long time,, have only (1-1/K) with capacity common double winding transformer because autotransformer self short-circuit impedance is little ²Doubly, the short circuit current of transformer itself and electric power system is significantly increased, excellent its is middle-size and small-size transformer, and be more outstanding.These deficiencies have restricted the large-scale popularization and the application of autotransformer to a certain extent.

At present, it is all relatively more rare both at home and abroad to be applied to the pertinent literature and the product of field transformer about integrated magnetic, once has a small amount of paper and patent also only to relate to isolating transformer in recent years.

Summary of the invention:

The purpose of this utility model is to provide a kind of novel high impedance autotransformer, can solve the little deficiency of autotransformer short-circuit impedance.

The utility model is to be achieved through the following technical solutions:

A kind of novel high impedance autotransformer, iron core comprises main iron core, secondary iron core, main iron core is the main loop of main flux, adopts stem stem and horizontal yoke to open gap structure; Secondary iron core is the main loop of leakage flux, and secondary iron core is opened air gap according to the short-circuit impedance size on stem stem; Winding is divided into common winding and series connection winding, and with one of them winding only on main iron core, another winding is then on main iron core and secondary iron core.

Described winding connects into star connection or connects into the extend-triangle connection; On winding construction, air duct is set.

The autotransformer that the utility model provides has following advantage:

1, adopt the main loop of secondary iron core, can significantly improve the short-circuit impedance of autotransformer as leakage flux, and can be to its any adjustment in a big way.Because short-circuit impedance and short circuit current are inversely proportional to, and make its short circuit current significantly reduce, can accomplish less than or much smaller than isolating transformer with capacity, and cost much less.Just can change the leakage flux size by adjusting secondary iron core air gap, thereby change leakage inductance, promptly change short-circuit impedance.

2, can just can adjust the no-load transformer electric current by adjusting main iron yoke air gap, also can adjust the three-phase output voltage degree of balance, and can reach 0.25%.

3, air duct is set on winding construction, can reduces temperature rise; And the employing vacuum paint dipping, reduce noise.

4, overcome the existing little defective of autotransformer short-circuit impedance, help applying.

Description of drawings:

Accompanying drawing 1 is implemented structural representation for the utility model.

Embodiment:

See shown in the accompanying drawing 1, novel high impedance autotransformer described in the utility model, its iron core comprises main iron core 1, secondary iron core 2, main iron core 1 is the main loop of main flux, adopts stem stem and horizontal yoke to open gap structure; Secondary iron core 2 is the main loop of leakage flux, and secondary iron core is opened air gap according to the short-circuit impedance size on stem stem, and air gap can be opened between the steel disc; Winding is divided into common winding and series connection winding, and with one of them winding only on main iron core 1, another winding is then around main iron core 1 and secondary iron core 2 on both.Among the figure, when being used for the step-down use, the series connection winding is the winding 4 of winding outside; When using when being used to boost, the series connection winding is the winding 3 in the lining winding, and common winding is then to change.

Winding connects into star connection usually, if consider the filtering harmonic wave, also can connect into the extend-triangle connection.Air duct 5 is set on winding construction, and air duct 5 can reduce temperature rise; In reality processing, adopt vacuum paint dipping, can reduce noise.

The utility model utilizes integrated magnetic can solve the little deficiency of autotransformer short-circuit impedance, and its advantage is further widened, and main feature is as follows:

1), increases short-circuit impedance, reduction short circuit current

Adopt the main loop of secondary iron core, can significantly improve the short-circuit impedance of autotransformer as leakage flux, and can be to its any adjustment in a big way.Because short-circuit impedance and short circuit current are inversely proportional to, and make its short circuit current significantly reduce, can accomplish less than or much smaller than isolating transformer with capacity, and cost much less.Just can change the leakage flux size by adjusting secondary iron core air gap, thereby change leakage inductance, promptly change short-circuit impedance.

2), filtering harmonic wave

When power supply is sine wave, odd harmonic mainly appears, and based on 3 subharmonic content.When adopting triangle to connect, can be 3 subharmonic and the 3n subharmonic provides path, make it not flow into load or electrical network.In view of the limitation of interior delta connection no-load voltage ratio, if necessary, the utility model can adopt the extend-triangle connection.The more important thing is that its calculated capacity is littler, cost is lower, is example with 3 Φ, 380/3 φ 220, and establishing the isolating transformer calculated capacity is 1, and then interior triangle is 0.663, and extend-triangle is 0.456, and star connection is 0.421.

3), reduce filter capacitor

On some precision voltage source equipment, tend to insert electric capacity and inductance, its high order harmonic component is filtered, according to formula $f=\frac{1}{2\mathrm{\π}\sqrt{\mathrm{LC}}}$ As can be known, the increasing of transformer leakage inductance L helps reducing of filter capacitor C.

4), cost is low, performance is excellent

Because leakage flux is mainly by secondary iron core, and secondary iron core is the ordinary silicon steel, helps further suppressing high order harmonic component.In fact, it is integrated that the utility model can be equivalent to that a reactor and autotransformer have been carried out magnetic, but its not only cost minimizing, and performance is much better than series connection one reactor before autotransformer, because magnetic integrated " reactance winding " has not only played the inductance effect, carry out the effect of inductance coupling but also play the generation main flux.

5), cost, volume, weight, loss contrast

For can clearer explanation the utility model in the superiority aspect the parameters such as cost, volume, weight, loss, existing with the often supporting 100KVA dry-type three-phase transformer of shop equipment be that example is calculated, and will the results are shown in table 1 separately.For unified its method for designing, regulation: 1.. voltage ratio: 380V/200V; 2.. the class of insulation: the H level, temperature rise designs at 115 ± 8 ℃, if the higher or on the low side need of temperature rise are adjusted relevant parameter; 3.. iron core is selected principle for use: section factor gets 1.0, and the window height is that 3 times of sheets are wide, and window width is decided according to line bag actual size; 4.. short-circuit impedance: 8 ± 0.5%, satisfy by adjusting the number of turn, air flue size and secondary iron air gap.5.. material is by 08 year market price: 18 yuan/kg of iron (35W300), and enamel covered wire: 78 yuan/kg, other calculates by 15%.

Table 1:

Electric current and voltage for series connection winding and common winding calculates, the major-minor core section is chosen, the calculating of secondary iron air gap, air flue placement, short-circuit impedance calculating, temperature rise calculating, Structure Calculation etc., can utilize computer technology to be compiled into software, thereby carry out optimal design.

The utility model significantly improves its short-circuit impedance and can adjust in a big way, possesses a lot of functions that isolating transformer is arranged, and can use in a lot of places.Such as: can be used on distribution, power-equipment, UPS transformer, subway, navigation of some factories etc.

Claims (3)

1, a kind of novel high impedance autotransformer is characterized in that: iron core comprises main iron core (1), secondary iron core (2), and main iron core (1) is the main loop of main flux, adopts stem stem and horizontal yoke to open gap structure; Secondary iron core (2) is the main loop of leakage flux, and secondary iron core is opened air gap according to the short-circuit impedance size on stem stem; Winding is divided into common winding and series connection winding, and with one of them winding only on main iron core (1), another winding is then around main iron core (1) and secondary iron core (2) on both.

2, novel high impedance autotransformer according to claim 1, it is characterized in that: winding connects into star connection or connects into the extend-triangle connection.

3, novel high impedance autotransformer according to claim 1 and 2 is characterized in that: on winding construction, air duct (5) is set.

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