RU2551674C1 - Dc collector electric machine - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: DC collector electrical machine contains the main trapezoidal poles with the central and lateral non-magnetic inserts, minimum 5 pieces placed parallel to an axis of the main poles. Total width of non-magnetic inserts shall be no less than the size of the uniform air gap between the main pole and the armature. The central non-magnetic inserts have the height equal to the total height of the inductor core and the yoke magnetic conductor along the main pole axis. The height of lateral non-magnetic inserts decreases at approach to lateral surfaces of the core of the main poles. The invention allows to reduce negative impact of the armature field and to implement the motor design with a uniform air gap without damping windings on the main poles.

EFFECT: invention allows to increase motor efficiency due to reduction of electric losses in additional poles.

5 dwg

Description

The present invention relates to the field of electrical engineering, in particular to the design of direct current electric collector machines with distinct poles used in industrial and traction units as engines and generators.

Known electric DC collector machine with pronounced poles, having a non-magnetic insert in the core of the main pole. The stator of a DC collector electric machine with pronounced poles consists of n separate parts of the magnetic circuit equal to the number of poles p. Each part contains one arm of the stator yoke and two halves of the core of the main pole. The parts of the stator magnetic circuit are fastened together by connecting elements made in the form of plates of non-magnetic metal, which are located at the ends of the magnetic circuit and are attached by welding or rivets to the parts of the stator magnetic circuit. The parts of the magnetic circuit fastened by non-magnetic metal form the stator core with a non-uniform non-magnetic gap between the parts of the magnetic circuit. Non-magnetic gap is located along the axis of the main poles. The gap has the smallest width in the region of the pole pieces and the largest width in the region of the core and yoke. Using this gap, an increase in magnetic resistance is achieved for power lines that distort the uniform distribution of magnetic flux at the pole division, and for power lines that increase the magnetic flux flowing in the switching zone of the armature field [patent No. 2107375 / C1, IPC H02K 1/14, H02K 23/42, publ. 1998.0.20].

However, the core of this machine, along with a significant increase in magnetic resistance to the armature field, also creates significant resistance to the inductor field. This is due to the large width of the non-magnetic insert in the core region, which is the main path of the magnetic flux of the inductor. An increase in the magnetic resistance of the inductor field along the axial line of the main pole leads to the appearance of a global minimum, which worsens the uniformity of the distribution of the magnetic flux at the pole divisions and reduces its value. In addition, the magnetic bridge in the pole tip with a magnetic induction in it of less than 1.8 T leads to a significant decrease in the magnetic resistance of the armature field and even greater distortion of the magnetic field under the main pole. This design of the core of the main poles reduces engine power and its overload capacity.

Also known is an electric DC collector machine with pronounced main and additional poles (AS No. 1601693, USSR, H02K 1/14), which is the prototype of the invention. The pole of this electric DC machine contains a core with a pole tip, recruited from sheets of electrical steel with a charge across the axis of the machine. A winding is fixed on the core, and the middle part of the pole core and pole tip is assembled from steel sheets with a charge along the axis of the machine. The pole is fixed to the yoke with screws placed in the plane of symmetry of the pole. The ends of these screws enter the rods embedded in the holes in the middle of the core and the pole piece and screwed into them. The rods may be in the form of an arc repeating the shape of the surface of the tip facing the working air gap. The middle part of the core is composed of identical sheets, each provided with holes for laying rods. The extreme parts of the core are connected to one another by a jumper. The shape of the interface surface of the jumper may repeat the shape of the surface of the pole piece facing the working air gap. This ensures the desired tip surface profile. The core content of the part with the batch of steel sheets along the axis of the machine creates additional magnetic resistance along the flow path created by the magnetic field of the armature windings, while not increasing the magnetic resistance for the magnetic flux generated by the field windings. This invention allows to reduce the influence of the magnetic field of the armature on the magnetic field of the inductor.

However, the indicated electric collector machine does not provide a significant increase in magnetic resistance for the armature field, distorting the uniform distribution of magnetic induction on the pole division, since the width of the non-magnetic gaps (between steel sheets lined across the longitudinal axis of the machine) located in the cores of the main poles is insufficient to create significant magnetic resistance. In addition, the part of the core with the charge across the axis of the machine has a height less than the total height of the pole piece, core and yoke, which leads to the redistribution of the magnetic flux of the armature field and most of the flow passes bypassing the inserts lined across the axis of the machine. In this design, for the part of the magnetic flux of the armature that worsens the switching conditions, no additional resistance is created, which leads to the use of the standard design of additional poles. Creating a uniform air gap between the pole piece and the anchor in this design is associated with significant difficulties in manufacturing the main pole with inserts. This design does not provide a sufficient reduction of the negative effects of the armature field on the inductor field, which leads to the use of standard methods to reduce the armature reaction, which reduce the power and efficiency of the engine.

The objective of the proposed electric DC collector machine with pronounced main and additional poles is to increase power and efficiency.

The task is achieved in that the main poles have a trapezoidal shape with central and side non-magnetic inserts in an amount of at least 5 pieces placed parallel to the axis of the main poles, the central non-magnetic inserts have a height equal to the total height of the inductor core and the yoke magnetic circuit along the axis of the main pole. The height of the side non-magnetic inserts in the left and right parts of the main poles decreases when approaching the side poles of the core of the main poles, so that in the nominal mode of operation of the machine saturation of the core parts does not occur. The air gap between the main poles and the surface of the armature is uniform. The total width of non-magnetic inserts must be at least the size of the air gap between the main pole and the armature.

Figure 1 shows a cross section of a quarter of the proposed design of a DC collector machine with pronounced trapezoidal poles and, for example, with 15 non-magnetic inserts.

Figure 2 shows the main path of the working magnetic flux F _{ind of} the inductor field in the magnetic circuit of a DC collector electric motor with distinct trapezoidal poles and, for example, with 15 non-magnetic inserts.

Figure 3 presents the main paths of the magnetic flux of the armature field in the magnetic circuit of a DC collector electric motor with pronounced trapezoidal poles and, for example, with 15 non-magnetic inserts.

Figure 4 presents the distribution of the normal component of the magnetic induction at the pole division for the engine with the proposed design of the magnetic circuit (figure 1), modeled in a finite element package FEMM. The dimensions of the motor correspond to the dimensions of the EDM-114 traction motor, the engine power is increased by 9%, the uniformity of distribution is increased by 19%, and the magnetic flux in the switching zone is reduced by 5%.

Figure 5 presents the main geometric parameters of non-magnetic inserts in the core and the yoke of the main poles of DC collector motors.

The proposed design of an electric DC collector machine with distinct poles (Fig. 1) consists of trapezoidal main poles (1), field windings (2), yoke (3), non-magnetic inserts (4, 5), armature (6), additional poles (7 ′, 7) and their windings (8 ′, 8). Non-magnetic inserts (4, 5) are located at the main poles (1) and the yoke (3). The axis of the central inserts (5) is located on the axis of the main poles (1) and has a height equal to the sum of the heights of the core of the main pole h _heart and yoke h _yokes (Fig. 5). Side inserts (4) are placed symmetrically with respect to the central inserts (5) (Fig. 1). The total number of side non-magnetic inserts (4) must be at least 4 pieces in each main pole. The height of the side inserts (4) decreases toward the edge of the main pole (1).

The proposed electric DC collector machine with pronounced poles works as follows.

The magnetic flux Ф _ind created by the excitation winding (2, 2 ′) flows through the core of the main pole (1 ′), yoke (3 ′), yoke (3), core of the main pole (1), air gap (9), core anchors (6), air gap (9 ′), core of the main pole (1 ′) (figure 2). Non-magnetic inserts (4, 5) are placed parallel to the main flow paths f _ind , due to which they do not create additional magnetic resistance to this flow.

The magnetic flux Ф _yak , created by the windings of the armature with clearly defined stator poles, can be divided into two parts Ф _yk1 and Ф _yak2 flowing through different parts of the magnetic circuit.

The first part of the flow of the anchor Ф _yak1 (Figure 3) flows through the core of the armature (6), the air gap (9 ′), the left side of the core of the main pole (1 ′), along the bottom of the core of the main air gap (from 1 ′ to 1) , the right side of the core of the main pole (1), the air gap (9), the core of the armature (6). The distribution of non-magnetic inserts (4, 5) along the width of the main pole (1) provides an increasing magnetic resistance to the armature field when moving away from the axis of the main pole (1), the magnitude of the magnetizing force of the armature (8) depends on the distance from the axis of the main pole (1), determined according to the well-known formula:

F _yak = And _I x;

where x is the distance from the axis of the main pole;

And _{I am the} linear load of the anchor.

By arranging non-magnetic inserts parallel to (4, 5) the axis of the main pole and reducing the height of the side inserts (4) depending on the distance from the axis of the main pole, a minimum increase in magnetic resistance for the flux Φ _{ind is} achieved. The height of the side inserts h _b.i. (i is the insertion number, reference is the center insert, Fig. 5) depends on the number of side inserts, the shape of the main pole, the material of the magnetic circuit and the distribution of the resulting magnetic flux. The height h _b.i should be less than the height of the core h _s.i (Fig. 5) at the location of this non-magnetic insert and the gap h _p.i between the insert and the edge of the main pole should not be saturated at the rated engine operating mode (figure 5). The determination of h _{P.i is} made using finite element modeling of the machine’s magnetic field when feeding the field windings and the armature windings in the final part of the electromagnetic design of the engine. A part of the magnetic flux of the armature Ф _як1 , flowing along the first path, leads to a distortion of the uniform distribution of the main magnetic flux at the pole division, which leads to an increase in the electrical voltage between the lamellas and a decrease in the resulting magnetic flux at the pole division (decrease in motor power). The increase in magnetic resistance of the armature field in the main poles significantly reduces the distortion of the inductor field and its distribution on the pole division when the number of non-magnetic inserts is greater than or equal to 5 pieces approaches the distribution of the magnetic flux at idle (Figure 4). When reducing the number of non-magnetic inserts to less than 5 pieces to create sufficient magnetic resistance to the armature field, the width of each insert increases significantly, which ultimately leads to pulsation of the magnetic flux at the pole division and the creation of additional magnetic resistance for the inductor field. An increase in the number of inserts of more than 5 pieces leads to a decrease in pulsations of the magnetic flux and magnetic resistance for the flux f _ind

The second part of the flow of the anchor Ф _yak2 (Figure 3) flows through the core of the armature (6), the air gap (10 ′), the core of the additional pole (7 ′), the yoke (3 ′), the yoke (3), the core of the additional pole (7 ), air gap (10), core of the armature (6). The central non-magnetic insert (5) intersects all the lines of force of the armature stream Ф _yak2 and provides additional magnetic resistance. Furthermore, part of the side nonmagnetic inserts having a height h _serd <h _BV <h + h _{serd yokes} create additional flow resistance F _{Yakovlev Yak-2.} With a significant increase in the magnetizing force of the magnetic field of the armature, the magnetic circuit between non-magnetic inserts with a height of h _heart <h _bv <h _heart + h _yokes located near the central insert and the outer boundary of the yoke is saturated increasing the magnetic resistance to the armature flux Ф _yk2 . The flow Φ _yak2 complicates the switching process and leads to the use of additional poles to ensure satisfactory switching. The proposed core provides additional resistance in the path of this flow and, as a result, reduces its value in the switching zone, which reduces the negative influence of the armature field in the switching zone and, as a result, the possibility of reducing the amount of copper used in additional poles.

The trapezoidal shape of the main pole eliminates the saturation of the core parts of the main pole in the nominal mode of operation, reducing the magnetic flux resistance f _ind from the side non-magnetic inserts.

The invention allows to increase engine power by reducing the negative effects of the armature field and providing conditions for the design of the engine with a uniform air gap between the main poles and the armature without additional means (compensation windings).

The invention also allows to increase the efficiency of the engine by reducing electrical losses in the additional poles and achieving a magnitude of magnetic induction in the teeth of the armature of not more than 1 T.

Claims (1)

An electric DC collector machine with pronounced additional poles and main poles containing non-magnetic inserts, characterized in that the main poles have a trapezoidal shape with central and side non-magnetic inserts in an amount of at least 5 pieces parallel to the axis of the main poles, the central non-magnetic inserts have a height equal to the total height of the core of the inductor and the yoke magnetic circuit along the axis of the main pole, the height of the side non-magnetic inserts in the left and right parts of the head of the poles decreases as the main poles approach the lateral surfaces of the core, so that, during the nominal operating mode of the machine, parts of the core do not saturate, the air gap between the main poles and the armature surface is uniform, the total width of non-magnetic inserts must be at least the size of the air gap between main pole and anchor.

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