JPH0430408A - Transformer - Google Patents

Abstract

PURPOSE:To obtain a transformer having high percent impedance voltage by interposing a magnetic material between windings. CONSTITUTION:The title transformer is provided with an iron core 1, a primary winding 2 and a secondary winding 3 to be wound around the iron core 1, and a magnetic material 4 which is formed by winding around the iron core 1 provided between the above-mentioned windings. As the relative permeability of the magnetic material is large, leakage inductance is increased, and percent impedance voltage can be increased sufficiently without changing the overall size of a transformer and the size of a cooler. Also, the percent impedance voltage value can be adjusted in a wide range only by changing the thickness in axial direction and the permeability of the magnetic material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to transformers with high % impedance voltage.

[Conventional technology]

The % impedance voltage of a transformer is defined as the percentage of the voltage drop (referred to as impedance voltage) caused by the leakage impedance of the transformer when the rated current is applied to the rated voltage, and it improves the stability of the system to which the transformer is connected. This value is greatly related to the power consumption and short-circuit capacity. In other words, if the % impedance voltage of the transformer is too large, the voltage fluctuation rate will be too large, and if it is too small, the fault current in the event of a short circuit will increase, causing not only the transformer but also other series equipment to become mechanically or There is a risk that it will turn blue due to heat. Therefore, although the standard % impedance voltage is usually around 10%, it is determined by the user's specifications, and the transformer is designed to fit within the required value.

FIG. 2 is a half-sectional view showing an example of the configuration of a conventional transformer, showing an iron core 1 and a primary winding around this iron core 1! 2 and 2nd order t1&lI3.

In the configuration shown in Fig. 2, it is well known that the leakage inductance L0 converted to the primary side is expressed by the following formula (
For example, Noboru Ooka, "Transformer", 1968, Tokyo Denki University Press, 173) 6h where, μ. : Vacuum permeability (4πXl0-' II/■)N
: Number of turns of secondary winding NlA2 1 : Average value of average circumference of primary winding 2 and secondary winding 3 (m) α : Insulation gap between primary tI & lI2 and secondary winding 3 (m
) dl: Radial width of primary winding 2 (m) d3: Radial width of secondary winding 3 (m) h: Primary winding 2. Secondary @wA
The height (m) k of 3 is a correction coefficient and is based on the following equation.

π h If the rated current of the primary side is , the rated voltage of the primary side is
*) is from the above definition, (%I Z@)” (2πf Le ' I/V) x
ioo (3), so the capacity of the transformer is P(-
Vl), then (V/N)”h d, +d.

+ ) +
41, and (%IZ*) can be calculated from equation 4.

Therefore, in order to adjust the % impedance voltage of the transformer to a higher value, measures such as increasing α from equation (4) or decreasing V/N have been used.

[Problem to be solved by the invention]

However, the conventional device as described above has problems such as an increase in the size and weight of the entire transformer or an increase in the size of the cooler when a high % impedance voltage is required.

That is, when α is increased, the diameter of SwA increases, which in turn increases the size and weight of the entire transformer. Furthermore, since reducing h leads to an increase in the radial width (atdX) of the winding, as can be seen from equation (4), %z does not increase much and is not very effective.

Furthermore, there is also a method of increasing N so that V/N becomes smaller.
As the amount of T11AW4 material increased (so-called copper equipment), the load loss increased and the cooler had to be made larger, leading to an increase in costs.

An object of the present invention is to provide a transformer having a high % impedance voltage by interposing a magnetic material between the windings.

[Means to solve the problem]

In order to solve the above problems, the present invention includes an iron core, a primary winding and a secondary winding around which the iron core is wound, and a gap between the primary winding and the secondary winding. A magnetic body is provided in the iron core and is formed to orbit the iron core.

[Effect]

According to the configuration of the present invention, by providing the magnetic body formed so as to circulate around the iron core between the primary @ wire and the secondary @ wire, the leakage inductance is reduced because the relative magnetic permeability of the magnetic body is large. increases, thereby causing the transformer to have a high % impedance voltage.

(Example〕 The present invention will be explained below based on examples.

FIG. 1 is a half-sectional view showing the configuration of a transformer according to an embodiment of the present invention, and includes an iron core 1 and a winding 1 around which the iron core 1 is wound.
It has a configuration including a secondary winding 2 and a secondary winding 3, and a magnetic body 4 provided between these windings and formed so as to go around the iron core 1.

When the equation for calculating the leakage inductance L in the embodiment shown in FIG. 1 was derived, the following equation was obtained, and it was found that it matched well with the actually measured value.

h 10μ. μ3 N” J T − (51 where, T,
μ is the radial thickness [m] and relative magnetic permeability of the magnetic body 4, respectively, and other symbols are the same as defined in equation (1).

From formula (5), the % impedance voltage (%1z) is (V
/N)”h d, +d.

+ ) tenμ.

T) becomes.

In equation (6), the term related to (α-T) is the leakage inductance corresponding to the insulation gap between the @ wires, (
The term related to d + + d 3) is the leakage inductance corresponding to the primary winding 2 and secondary winding 30 portion, and the term related to μsT is the leakage inductance corresponding to the magnetic body 4 portion. Comparing Equation (6) with Equation (4) in the conventional structure, the term α has been reduced to (α-T), but the terms μ and T have increased in its place. Since the value is 100, the overall value is (from formula 4, (
It has been discovered that (%IZ) of formula 6) becomes higher, and that the %impedance voltage can be effectively increased only by interposing the magnetic material 4.

For example, α-0,02Cm), dt-dg-
0,06(m), T=O,OOl(m),l
% of formula (6) and formula (4) in case of 5-100
Calculating the ratio of impedance voltage, (%IZ)/(
%I Z , ) -0,1610,06-2,67, and the % impedance voltage can be easily increased even with a fairly thin magnetic body 4 having a thickness T. Therefore, even if the required α dimension is increased by T from the viewpoint of insulation, since T can be made thinner, the increase in the overall size and weight of the transformer is hardly affected.

In the embodiment shown in FIG. 1, if the magnetic body 4 is an isotropic silicon steel plate, it is advantageous to align the direction with the axial direction of the tL line because μ becomes larger. In addition, in the embodiment shown in FIG. 1, the magnetic body 4 is arranged over the entire opposing surface of the primary winding 2 and the secondary winding 3, but in a different embodiment of the present invention, a plurality of magnetic bodies 4 are arranged. Even when the magnetic body is divided and a gap is created between the windings, or when the axial height of the magnetic body 4 is smaller than h, the % impedance voltage is smaller than the formula (6), but the conventional method shown in Fig. 2 The % impedance voltage is larger than the % impedance voltage of the structure, and the % impedance voltage can be sufficiently increased.

Further, although the embodiment shown in FIG. 1 is an example of an inner iron type transformer, the % impedance voltage can also be increased by applying the present invention to an outer iron type transformer.

〔Effect of the invention〕

As described above, in this invention, a magnetic material surrounding an iron core is provided between the primary winding and the secondary winding, so that when the % impedance voltage is increased, the overall dimensions of the transformer are reduced. To provide a device which solves the disadvantages of increasing the size of the transformer and the size of the cooler, and can sufficiently increase the % impedance voltage without changing the overall dimensions of the transformer or the size of the cooler. This has the advantage that a transformer with a high % impedance specification can be made more compact.

Another advantage is that the % impedance voltage value can be adjusted over a wide range simply by changing the radial strength or magnetic permeability of the magnetic material.

[Brief explanation of drawings]

FIG. 1 is a half sectional view showing the structure of a transformer according to an embodiment of the present invention, and FIG. 2 is a half sectional view showing an example of the structure of a conventional transformer.

Claims (1)

[Claims] 1) It consists of an iron core and a primary winding and a secondary winding that are wound around the iron core, and is formed between the primary winding and the secondary winding so as to go around the iron core. A transformer characterized by comprising a magnetic material.