RU167365U1 - ELECTROMY CONVERTER FOR REDUCED FREQUENCY - Google Patents

Abstract

The utility model relates to electrical engineering, in particular to machine frequency converters, and can be used to convert the voltage of the original frequency to the voltage of the required low frequency. The electric machine for low frequency contains a stator 1 and a clearly-shaped rotor 4. In the grooves of the stator 1, a two-layer six-zone three-phase motor is first placed winding 2 ac. The three-phase AC motor winding 2 forms a number of rpar poles and is connected to a voltage source of the original frequency. Then, a three-phase alternating current winding 3 with a relative pitch β = 1-p / p is laid in the grooves of the stator. Three-phase alternating current generator winding 3 forms a number of pole pairs and is connected to the voltage consumer of the required reduced frequency. The wave-polar rotor 4 forms the same number of pole pairs p with the three-phase generator winding 3 of alternating current. The number of formed pairs of poles is a multiple of the number ri at the same time is not a multiple of the number 2p.

Description

The utility model relates to electrical engineering, in particular to machine frequency converters, and can be used to convert the voltage of the original frequency to the voltage of the required reduced frequency.

Known electric machine converter to obtain a reduced frequency (USSR author's certificate No. 687534, publ. September 25, 1979), consisting of a stator with a multiphase single-layer combined winding made of concentric coils forming 2 m coil groups shifted by π radians.

The disadvantage of this technical solution is the complexity of the stator winding circuit.

Known electric machine converter to obtain a reduced frequency (Electric machines 4.1 / D.E. Bruskin, A.E. Zorokhovich, V.S. Khvostov. - M .: Higher school, 1973, S. 246-247), consisting of two asynchronous cars. Each of the machines has a stator and a rotor, and the rotors have a rigid mechanical connection. The rotor of one of the asynchronous machines, which operates in a motor mode, is equipped with slip rings, to which its phase winding is connected, and from which the voltage of low frequency is removed.

The disadvantage of this technical solution is the need to use two electric machines, while the electric frequency converter has a relatively high weight and dimensions.

Known electric machine frequency converter (USSR author's certificate No. 130966, publ. 01.01.1960), containing on the stator motor and generator windings for different numbers of poles and explicit pole rotor.

The disadvantage of this technical solution is the limited functionality that does not allow to obtain a reduced frequency of the output voltage.

Known single-arm asynchronous non-contact frequency converter (USSR author's certificate No. 148847, publ. 01.01.1962), containing a stator with two inductively unconnected windings, the ratio of the number of poles of which is equal to the frequency ratio, and a buried claw-shaped rotor with a pathogen of permanent magnets.

The disadvantage of this technical solution is that the rotor has a complex low-tech design with claw-shaped poles.

Known electric frequency converter (Synchronous machines of autonomous power supplies / L.M. Palastin. - M .: Energy, 1980, C 6-7), adopted as a prototype consisting of two synchronous machines (three-phase motor and generator), each of which contains a stator with windings mounted on one base, and rotors placed on a common shaft. The stator winding of the motor is multi-pole with the number of pole pairs p ₁ and connected to a voltage source of the original frequency. The generator driven by it in rotation contains a stator with a winding located in the grooves with the number of pole pairs p ₂ , and p _{2 is} less than p ₁ . In this case, the voltage of the required reduced frequency is removed from the generator winding.

The disadvantage of this technical solution is the relatively low overall dimensions, due to the need to use two separate electrical machines.

The technical result is to improve the overall dimensions of the machine converter to obtain a reduced frequency.

, при этом обмотки выполняются так, что число пар полюсов р₁ кратно числу р₂ и одновременно не кратно числу 2р₂.The technical result is achieved by the fact that the rotor is made explicitly polar and forms the same number of pole pairs p ₂ with the three-phase alternating current generator winding, and the three-phase alternating current motor winding is made of two-layer six-zone, and the three-phase alternating current winding with relative pitch is laid in the stator slots on top of it

, while the windings are made so that the number of pole pairs p _{1 is a} multiple of p ₂ and at the same time is not a multiple of 2p ₂ .

The electric machine converter for low frequency is illustrated by the following figures:

FIG. 1 is a diagram of an electric machine converter for a reduced frequency,

FIG. 2 is a diagram of the stator windings of an electric machine converter for a reduced frequency, where:

1 - stator;

2 - three-phase AC motor winding;

3 - three-phase alternating current generator winding;

4 - explicit pole rotor;

5 - south magnetic pole formed by a three-phase AC motor winding;

6 - North magnetic pole formed by a three-phase AC motor winding;

7 - south magnetic pole formed by a three-phase alternating current generator winding;

8 - north magnetic pole formed by a three-phase alternating current generator winding.

, что исключает ее взаимоиндуктивную связь с трехфазной двигательной обмоткой 2 переменного тока. Число пар полюсов р₁ кратно числу р₂ и одновременно не кратно числу 2р₂. Стороны секций трехфазной двигательной обмотки 2 переменного тока расположены под полюсами одной полярности трехфазной генераторной обмотки 3 переменного тока. Явнополюсный ротор 4 имеет одинаковое с трехфазной генераторной обмоткой 3 переменного тока число полюсов р₂. На фиг. 2 показаны схемы трехфазных двигательной 2 и генераторной 3 обмоток статора. Направления токов в фазах обмоток указаны стрелками, в соответствии с этими направлениями расставлены магнитные полюса, создаваемые обеими обмотками 5, 6, 7, 8.An electric machine converter for a reduced frequency consists of (Fig. 1) a stator 1 and an explicitly polar rotor 4. Three-phase motor 2 and generator 3 AC windings are placed in the grooves of the stator 1. The three-phase AC motor winding 2 is made of a two-layer six-zone (with a phase zone of 60 °) and forms a number p _{1 of} pairs of poles, and is connected to a voltage source of the original frequency. The three-phase alternating current winding 3 forms a number p ₂ of pole pairs, and p _{2 is} less than p _1, it is connected to the voltage consumer of the required reduced frequency and is made with a relative step

, which eliminates its mutual inductive coupling with a three-phase motor winding 2 of alternating current. The number of pole pairs p _{1 is a} multiple of p ₂ and at the same time is not a multiple of 2p ₂ . The sides of the sections of the three-phase AC motor winding 2 are located under the poles of the same polarity of the three-phase AC generator winding 3. The main pole rotor 4 has the same number of poles p ₂ with the three-phase alternator current winding 3. In FIG. 2 shows a diagram of a three-phase motor 2 and generator 3 stator windings. The directions of the currents in the phases of the windings are indicated by arrows, in accordance with these directions are the magnetic poles created by both windings 5, 6, 7, 8.

.The device operates as follows. When bringing to a three-phase motor winding 2 an alternating voltage of the initial frequency ƒ ₁ on stator 1, a magnetic field is formed with the number of pole pairs p ₁ , rotating with speed

.

After pulling the explicitly polar rotor 4 into synchronism, which can be achieved by known methods, for example, as in a conventional synchronous motor due to the placement of a starting winding on it, it starts to rotate with a field speed n ₁ . At the same time, its clearly expressed poles will be oriented (without taking into account the angle ψ between the EMF and the current) almost opposite the poles of opposite polarity formed by a three-phase AC motor winding 5, 6. In this case, the explicit pole rotor 4 can be excited and create its own magnetic poles due to electromagnetic excitation (DC excitation windings) or magnetoelectric excitation (permanent magnets).

An explicit pole rotor 4 rotating at a synchronous speed n ₁ induces in the three-phase generator winding 3 an alternating current EMF of frequency

раз частотыƒ₂, то по ней пойдет ток, который создаст собственное, вращающееся со скоростью магнитное поле, создаваемое полюсами 7 и 8. Но поскольку ƒ₂=р₂n₂, то n₂=n₁, т.е. поля трехфазной двигательной 2 и генераторной 3 обмоток переменного тока, образуя разные числа полюсов, будут вращаться с одной и той же скоростью синхронно с явнополюсным ротором 4.If a three-phase alternating current winding 3 is connected to a consumer with a reduced

Since frequency ƒ ₂ , then a current will pass through it, which will create its own magnetic field rotating with speed, created by poles 7 and 8. But since ƒ ₂ = p ₂ n ₂ , then n ₂ = n ₁ , i.e. the fields of the three-phase motor 2 and generator 3 windings of alternating current, forming different numbers of poles, will rotate at the same speed synchronously with the explicit pole rotor 4.

Thus, although the three-phase motor 2 and generator windings 3 of an alternating current are structurally located in a common magnetic circuit, they practically do not have transformer coupling between each other, therefore they work independently of each other. The use of this design of the machine converter allows you to lower the frequency and, due to a more rational layout of the active parts, significantly improve its overall dimensions.

Claims (1)

A low-frequency electric machine converter, including a rotor, and a stator, in the slots of which there is a three-phase AC motor winding forming a number p ₁ pole pairs and connected to an initial frequency voltage source, and a three-phase AC winding, forming a p ₂ pole pairs and the voltage of the required reduced frequency connected to the consumer, and p _{2 is} less than p ₁ , characterized in that the rotor is made explicitly polar and forms the same with a three-phase generator winding th alternating current, the number of pole pairs is p ₂ , and the three-phase AC motor winding is made of two-layer six-zone, and the three-phase alternating current winding with a relative pitch is laid in the stator slots on top of it

, while the windings are performed so that the number of pole pairs p _{1 is a} multiple of p ₂ and simultaneously not a multiple of 2p ₂ .