CN100498992C - Single phase AC step transformer - Google Patents

Abstract

The invention discloses a single-phase AC step-down transformer. In the transformer, the magnetic core is designed as a "return-shaped" body with a boss in the center and sides around it. The boss of the "return-shaped" body and A groove is formed between the surrounding sides, the primary coil and the secondary coil are stacked in the groove of the magnetic core, and the magnetic yoke is covered on the upper surface of the magnetic core. Therefore, the core and the yoke completely envelop the primary coil and the secondary coil, the magnetic field generated by the core and the yoke basically has no magnetic leakage phenomenon, and the magnetic fields in all directions are fully utilized. Compared with the traditional AC step-up transformer, the transformer has less magnetic loss, and the magnetic conversion efficiency has been better improved. Under the same setting conditions, the cross-sectional area of the magnetic core and the coil winding are small, and the temperature rise is low, so that The cost of raw materials for transformer production is reduced, the volume and weight are reduced, and the efficiency of the transformer is improved.

Description

Single Phase AC Step-Up Transformer

technical field

The present invention relates to an AC transformer, more specifically to a single-phase AC step-down transformer.

Background technique

According to Faraday's law of electromagnetic induction, in an alternating circuit, the magnetic lines of force change at any time, which can change the level of voltage and the magnitude of current. Based on this principle, people have manufactured various transformers and are widely used in power transmission, power supply, and electricity consumption, as well as telecommunications. , automatic control and other fields. There are many types of transformers, and their structures have their own characteristics, but their basic principles are the same or basically the same. Traditional transformers are mainly composed of coils and iron cores. Their structures are nothing more than shell type and core type. , put the coil on a closed magnetic core to form an induction mode in which the circuit is surrounded by a magnetic circuit, and an induced electromotive force is generated in the transformer core to transmit electric energy to achieve the working purpose of the transformer. As shown in Figures 1 and 2, the structure of an AC step-up transformer 10 is illustrated. In the figure, 11 is a magnetic core, which is shaped like an "E" with an upward opening, 12 is a yoke, and 13 and 14 are respectively primary and secondary. Level coil, wherein the magnetic core 11 and the yoke are formed by stacking many silicon steel sheets with the same cross-sectional shape. The direction of the magnetic force lines 15 of this transformer is shown in Figure 3. Since the two sides of the coil are exposed outside the magnetic core, the utilization rate of the free magnetic force lines is low and wasteful. This is a typical "circuit surrounding the magnetic circuit" "structure. The general step-up and step-down transformers adopt this structure, such as step-up and step-down transformers for microwave ovens, machine tools, and high-power flood light sources. The input voltage is 220V, and the output voltage is in the kilovolt range. The disadvantage of this type of step-up transformer is that part of the magnetic field on both sides of the coil cannot be fully utilized, and the magnetic flux leakage is large, resulting in low efficiency of the transformer, and the large volume of the transformer also causes a large waste of cost.

Contents of the invention

The object of the present invention is to propose a single-phase AC step-down transformer with high magnetic conversion efficiency, small size and low cost in view of the above-mentioned shortcomings of the traditional step-down transformer.

In order to achieve the above object, the present invention adopts the following technical scheme, the single-phase AC step-down transformer includes a magnetic core, a magnetic yoke, a primary coil, and a secondary coil,

It is characterized by:

The magnetic core is a "back-shaped" body with a boss in the center and sides around it. A groove is formed between the boss of the "back-shaped" body and the sides around it, and the upper end of the "back-shaped" body is open. , the lower end surface is closed;

The primary coil and the secondary coil are stacked in the groove formed by the boss of the magnetic core and the surrounding sides;

The magnetic yoke covers the upper end surface of the magnetic core.

The surrounding sides of the "back-shaped" body of the magnetic core are vertical surfaces, and symmetrical gaps are left on the four opposite corners of the magnetic core;

The primary coil and the secondary coil are square.

The yoke is in the shape of a "cross".

The magnetic core is formed by stacking longitudinal silicon steel sheets;

The magnetic yoke is formed by stacking longitudinal silicon steel sheets.

The side of the "back-shaped" body of the magnetic core is an arc surface, and the four diagonal corners along the diameter direction of the magnetic core are left with symmetrical gaps;

The boss of the magnetic core is cylindrical, and a circular groove is formed between the side of the magnetic core and the boss;

The primary coil and the secondary coil are circular.

The shape of the magnetic yoke is disc-shaped, and there are symmetrical gaps along the four opposite corners along the diameter direction.

The magnetic core is formed by stacking longitudinal silicon steel sheets;

The magnetic yoke is formed by stacking longitudinal silicon steel sheets.

In the buck-boost transformer of the present invention, the magnetic core is designed as a "back-shaped" body with a boss in the center and sides arranged around it, and a groove is formed between the boss of the "back-shaped" body and the surrounding sides. The primary coil and the secondary coil are stacked in the groove of the magnetic core, and the magnetic yoke is covered on the upper end surface of the magnetic core. Therefore, the core and the yoke completely envelop the primary coil and the secondary coil, the magnetic field generated by the core and the yoke basically has no magnetic leakage phenomenon, and the magnetic fields in all directions are fully utilized. Compared with the traditional AC step-up and step-down transformers, the step-down and step-down transformers of the present invention have less magnetic loss, and the magnetic conversion efficiency is better improved. Under the same setting conditions, the cross-sectional area of the magnetic core and the coil winding are less , Low temperature rise, thereby reducing the cost of raw materials for transformer production, reducing volume and weight, and improving the efficiency of the transformer.

Description of drawings

Figure 1 is a schematic diagram of the structure of a traditional step-up and step-down transformer.

FIG. 2 is an exploded schematic diagram of a traditional step-up and step-down transformer structure.

FIG. 3 is a schematic diagram of the direction of magnetic force lines of a conventional step-up and step-down transformer.

Fig. 4 is a structural schematic diagram of the buck-boost transformer of the present invention.

Fig. 5 is an exploded schematic diagram of the structure of the buck-boost transformer of the present invention.

Fig. 6 and Fig. 7 are schematic diagrams of stacking longitudinal silicon steel sheets of the yoke and the magnetic core of the present invention respectively.

Fig. 8 is a schematic diagram of the direction of the magnetic field lines of the buck-boost transformer of the present invention.

FIG. 9 is another structural schematic diagram of the buck-boost transformer of the present invention.

Fig. 10 is a schematic diagram of the direction of the magnetic force lines of another structure of the step-up transformer of the present invention.

Detailed ways

In order to further illustrate the above-mentioned purpose, technical solution and effect of the present invention, the present invention will be described in detail below through examples in conjunction with the above-mentioned figures.

Referring to FIG. 4 and FIG. 5 , the single-phase AC step-down transformer 20 of the present invention includes a magnetic core 21 , a magnetic yoke 22 , a primary coil 23 , and a secondary coil 24 .

The magnetic core 21 is a "back-shaped" body with a boss 211 in the center and side edges 212 around it. A groove 213 is formed between the boss 211 of the "back-shaped" body and the side edges 212 around it. "The upper end face of the body is open and the lower end face is closed.

The primary coil 23 and the secondary coil 24 are stacked in the groove 213 formed on the boss and the surrounding sides of the magnetic core.

The magnetic yoke 22 covers the upper surface of the magnetic core 21 .

The surrounding sides of the magnetic core 20 shown in FIG. 4 and FIG. 5 are all vertical surfaces, and the four opposite corners of the magnetic core 20 have symmetrical notches 214, and the primary coil 23 and the secondary coil 24 placed therein are square.

Correspondingly, the yoke 22 is a "cross" shape, so that it can just cover the magnetic core 21, and there are also symmetrical notches 221 at the four diagonal positions of the yoke 22, and the notches 221 and the notches 214 of the magnetic core 21 Corresponding. When making the magnetic core 21 and the magnetic yoke 22, the magnetic yoke 22 and the magnetic core 21 can be divided into the shapes of Fig. 6 and Fig. 7 respectively, which is convenient for processing and making in the process. The magnetic core 21 is made of several longitudinal silicon steel sheets. Similarly, the yoke 22 is also formed by stacking several longitudinal silicon steel sheets.

As another embodiment, please refer to FIG. 9 , at this time, the side of the "return" body of the magnetic core 21 is an arc surface, and the four opposite corners along the diameter direction of the magnetic core 21 have symmetrical gaps. The shape of the magnetic yoke 22 is disc-shaped, and there are symmetrical notches at four opposite corners of the yoke 22 along the diameter direction, and the notches correspond to the notches on the magnetic core 21 .

In this embodiment, the boss of the magnetic core 21 is cylindrical, and a circular groove is formed between the side of the magnetic core 22 and the boss. Due to the similar structure of the transformer based on the previous embodiment, the groove and the boss It is not shown in Fig. 9 .

Correspondingly, the primary coil 23 and the secondary coil 24 are circular.

While making,

The magnetic core 21 is formed by stacking several longitudinal silicon steel sheets;

The yoke 22 is formed by stacking several longitudinal silicon steel sheets.

Please refer to Fig. 8 and shown in Fig. 10 at last, as can be seen from these two figures, the magnetic field lines 25 are not wasted substantially, unlike the magnetic field lines on both sides of the traditional transformer are not fully utilized, obviously, the present invention The lines of force on both sides of the transformer are fully utilized, and there is basically no flux leakage phenomenon. From Faraday's formula V=-N(dΦ/dt)=-NBAω, the conversion efficiency of the transformer of the present invention can be proved.

In the formula, V is the generated voltage, N is the number of coil turns, dΦ/dt is the changing magnetic field, B is the magnetic field strength, A is the cross-sectional area of the magnet,

It can be seen that the voltage V is proportional to the product of the magnetic field strength B and the cross-sectional area of the magnet A, and the voltage is proportional to the number of turns of the coil. In the case of a set primary or secondary voltage, the number of turns of the coil and the cross-sectional area of the magnetic core The product of is a design constant, the greater the magnetic field strength, the greater the voltage generated, the larger the cross-sectional area of the magnet, the greater the voltage generated, and the higher the magnetic conversion efficiency.

Next, by referring to the table below, taking the Galanz WP900 microwave oven as an example, the performance indicators of the microwave oven using the transformer of the present invention and the microwave oven using the traditional transformer are explained.

As can be seen from the parameters shown in this table, under the condition that other performance indexes of the microwave oven are guaranteed to be constant, the weight of the coil, the iron core, and the microwave oven of the new microwave oven are all greatly reduced, which can further illustrate the performance of the transformer of the present invention. Superiority.

The step-up and step-down transformer of the present invention can design the magnetic core and yoke of the transformer in different shapes based on the above ideas. Of course, those of ordinary skill in the art should recognize that the above embodiments are only for illustration The present invention is not intended to limit the present invention. As long as it is within the spirit of the present invention, changes and modifications to the above-mentioned embodiments will fall within the scope of the claims of the present invention.

Claims (7)

1. A single-phase AC step-down transformer comprising a magnetic core, a yoke, a primary coil, and a secondary coil, characterized in that: The magnetic core is a "back-shaped" body with a boss in the center and sides around it. A groove is formed between the boss of the "back-shaped" body and the sides around it, and the upper end of the "back-shaped" body is open. , the lower end surface is closed; The primary coil and the secondary coil are stacked in the groove formed by the boss of the magnetic core and the surrounding sides; The magnetic yoke covers the upper end surface of the magnetic core. 2. The single-phase AC step-down transformer according to claim 1, characterized in that: The surrounding sides of the "back-shaped" body of the magnetic core are vertical surfaces, and symmetrical gaps are left on the four opposite corners of the magnetic core; The primary coil and the secondary coil are square. 3. The single-phase AC step-down transformer according to claim 2, characterized in that: said magnetic yoke is in the shape of a "cross". 4. The single-phase AC step-down transformer according to any one of claims 1-3, characterized in that: The magnetic core is formed by stacking longitudinal silicon steel sheets; The magnetic yoke is formed by stacking longitudinal silicon steel sheets. 5. The single-phase AC step-down transformer according to claim 1, characterized in that: The side of the "back-shaped" body of the magnetic core is an arc surface, and the four diagonal corners along the diameter direction of the magnetic core are left with symmetrical gaps; The boss of the magnetic core is cylindrical, and a circular groove is formed between the side of the magnetic core and the boss; The primary coil and the secondary coil are circular. 6. The single-phase AC step-down transformer according to claim 5, characterized in that: The shape of the magnetic yoke is disc-shaped, and there are symmetrical gaps along the four opposite corners along the diameter direction. 7. The single-phase AC step-down transformer according to claim 5 or 6, characterized in that: The magnetic core is formed by stacking longitudinal silicon steel sheets; The magnetic yoke is formed by stacking longitudinal silicon steel sheets.

Images