RU2343620C2 - Brushless direct current machine - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention is attributed to electric engineering and can be used as engine or direct current generator. Brushless direct current machine comprises body, coaxially positioned in it stator with windings, rotor with windings, bearings, rotor position sensor, circuit for voltage supply to rotor windings control. Body and shaft represent electrically insulated parts. Rotor position sensor output is electrically connected with circuit for voltage supply to rotor windings control. Control circuit is made using semiconductor switches. Rotor position sensor may be mechanical, capacitive or optical. Body separation into two electrically insulated parts permits to supply voltage to semiconductor control circuit via bearings. Such scheme in conjunction with usage of electroconductive lubricant eliminating bearing burning permits to exclude sparking, lower losses and improves control quality. Semiconductor control circuit supplies voltage to rotor windings depending on readings of rotor position sensor.

EFFECT: performance build-up.

1 dwg

Description

The invention relates to the field of electrical engineering and relates to design features of brushless DC electric machines intended for use as DC motors or generators.

Known electric machine described in the application of the Russian Federation No. 92012386 "Electric machine and method of its manufacture" according to cl. Н02К 15/02, 23/00, claimed December 16, 1992, publ. 03/10/95.

The known electric machine comprises a rotor part mounted on the shaft, a stator part with a switching unit housed in the housing, a centering element connected to the housing with a supporting collar, and also a pair of bearings under the ends of the rotor part shaft installed with limited rotation in the housing, while the surface of the centering element made spherical, and its shoulder is orthogonal to the axis of the shaft of the rotor part of the electric machine, and the center of the sphere of the centering element is located near the center of rotation near bearing bearing.

A disadvantage of the known electric machine is the design complexity due to the presence of a centering element.

Known brushless universal electric DC machine, described in the application of the same name No. 2004137225 class. Н02К 57/00, claimed December 20, 2004, publ. May 27, 2006

The known machine comprises a stationary stator made of soft magnetic steel, made in the form of a hollow cylinder, an annular winding, a windingless rotor with permanent magnets, while on the inner and outer sides of the stator parallel to its longitudinal side there are open longitudinal grooves arranged in a checkerboard pattern, fixed to the rotor shaft a disk, at the end of which two concentrically arranged hollow cylinders are located, covering the stator from its inner and outer sides, and on the outer surface of the inner th cylinder and the inner surface of the outer cylinder uniformly over their circumference taken by the same number of permanent magnets, and the plane of symmetry of each pair of the magnets coincide with the centreline of the rotor symmetry common to each pair of magnets, and like poles of the magnets face the stator.

A disadvantage of the known electric machine is the complexity of the design.

Known brushless universal electric DC machine, described in the same patent of the Russian Federation No. 2130682 by class. Н02К 27/00, 27/24, 23/54, claimed 13.02.98, publ. 05/20/99.

The known electric machine comprises a housing, a rotor with magnetic systems and a stator with multi-turn working windings, and there is at least one module in which a sleeve with external and internal magnetic systems is installed on the rotor shaft, between the poles of which there is a stator with an even or odd number of workers multi-turn windings with an even or odd number of working rows in them, inside the stator there is a control system for working rows of multi-turn windings, electrically connected with electronic switches, each module including a rotor formed with grooves for interaction with other modules.

A disadvantage of the known electric machine is the complexity of the design.

Although brushless DC electric machines are known, however, according to the applicant, the direct current electric machine, structurally closest to the claimed one, is described in the book: IP Kopylova “Electric machines”, M., “Higher School”, 2006 ., p. 482-495 and selected as a prototype.

A well-known direct current electric machine is a motor (the same, pages 490-492), to the bed of which are attached main poles with field windings and additional poles to ensure satisfactory switching, and on the shaft there is an armature magnetic circuit with a winding, sections of which are connected to the collector serving as a switch of winding sections, the machine armature is connected to the stator through bearing shields, in which there are bearings fixed by covers; a traverse is attached to one of the bearing shields, on which there are brush fingers with brush holders, in which there are brushes that provide sliding contact with the collector during rotation and serve as a current collector. To measure the rotational speed, a tachogenerator based on a direct current generator is mounted on the bearing shield. The bed is at the same time the yoke of the stator and the flow of excitation from the excitation windings is closed in it. The collector is usually used with graphite brushes.

With this design solution, due to the presence of rubbing parts of the contact group, it is impossible to exclude sparking, the brush assembly is worn out, which imposes great restrictions on the resource of the electric machine. The resistance in the brush assembly is comparable with the resistance of the rotor windings, which leads to losses and low efficiency. Together, this degrades the performance of the machine.

The challenge is to improve performance.

The problem is solved in that in an electric DC machine containing a stator part with windings located on the body, a rotor part mounted on a shaft with a winding connected to the commutator, and connected to the stator through bearing shields in which the bearings are located, associated with the collector elements, according to the invention, the housing and the shaft are divided into electrically insulated parts, a sensor is introduced to indicate the position of the rotor, connected to a switch, which is a They are a semiconductor circuit for controlling the supply of voltage to the rotor windings, and is fed through bearings with electrically conductive grease.

The separation of the housing and the shaft into two electrically isolated parts makes it possible to apply voltage to the semiconductor control circuit to the rotor windings through the bearings, which, together with the use of an electrically conductive lubricant that prevents burning of the bearings, eliminates spark formation, reduces losses and improves control quality.

The technical result is the provision of the ability to apply voltage to the control circuit through the bearings.

The claimed technical solution has a novelty in comparison with the prototype, differing from it by such significant features as the separation of the housing and shaft into electrically isolated parts, the introduction of a rotor position sensor connected to the input of the switch, the implementation of the switch in the form of a semiconductor circuit, voltage supply to the control circuit through bearings equipped with electrically conductive grease, which together ensure the achievement of a given result.

Although the implementation of the semiconductor switch is known (see the above book, p. 483), the applicant is not aware of the technical solutions possessing the indicated distinctive features, which together allow to obtain the desired effect, therefore he believes that the claimed brushless DC electric machine meets the criterion of “inventive step” ".

The inventive electric machine can find wide application in the field of electrical engineering as an engine or generator of direct or alternating current, and therefore meets the criterion of "industrial applicability".

The invention is illustrated in the drawing, which shows schematically a sectional view of the device.

The inventive brushless DC electric machine comprises a housing 1, a stator 3 with windings 4, a rotor 5 with windings 6, bearings 7, a rotor 5 position sensor 8, a voltage supply circuit for the rotor windings 5, coaxially placed therein on the shaft 2 of the stator 5. the housing 1 is divided into electrically isolated parts 1 'and 1' 'by means of an insulator 10, and the shaft is also divided into electrically isolated parts 2' and 2 '', the output of the rotor 5 position sensor 8 is electrically connected to the input of the voltage supply circuit of the windings 9 6 rotors 5. Scheme 9 control eniya formed on semiconductor keys, sensor 8 may be a mechanical, capacitive or optical.

The electric machine operates as follows.

A DC voltage from a source (not shown in the drawing) is applied between the parts 2 'and 2' 'of the shaft through the bearings 7. The circuit 9 for controlling the supply of voltage to the windings 6 of the rotor 5, based on the readings of the sensor 8 of the position of the rotor 5, supplies the voltage to the windings 6 in this way to create torque in the right direction. The windings 4 of the stator 3 are always powered in the same way and can be replaced by permanent magnets. After the rotor 5 is rotated to the next indication of the rotor 5 position sensor 8, the voltage supply control circuit 9 for the rotor 5 windings 6 switches the voltage on the rotor 5 windings so as to create a moment in the desired direction of rotation again. The use of an electrically conductive grease, such as HCG +, for bearings eliminates their burning.

Compared with the prototype of the inventive brushless DC electric machine has better performance.

Claims (1)

An electric direct current machine comprising a stator part located in the housing with windings located on the housing, a rotor part mounted on the shaft with a winding connected to the commutator, and connected to the stator through bearing shields, in which the bearings are connected to the collector elements, characterized in that the housing and the shaft are separated into electrically isolated parts, a sensor is introduced to indicate the position of the rotor, connected to a switch, which is a semiconductor control circuit Nia energizing the rotor winding and is fed through the bearings with electrically conductive grease.