WO1998038723A1

WO1998038723A1 - Method of converting electrical energy into mechanical energy of rotating shaft and method of producing mechanical energy of rotating shaft

Info

Publication number: WO1998038723A1
Application number: PCT/PL1998/000005
Authority: WO
Inventors: Dariusz Brylinski
Original assignee: Mrusek, Gregor
Priority date: 1997-02-26
Filing date: 1998-02-18
Publication date: 1998-09-03
Also published as: PL318668A1; PL183444B1

Abstract

In accordance with the method of converting electrical energy into mechanical one a magnetic field is produced by the electromagnets (1, 2). The magnetic field lines (11) in the air gap (1o) are perpendicular to the surface of ferromagnetic armature (3) coupled with the motor shaft (4). By means of the magnetic field the armature (3) is impelled to move in a direction parallel to the magnetic field lines (11) in the air gap (1o). In accordance with the method of producing mechanical energy of a rotating motor shaft equipped with the single magnetic circuit (1, 1o, 3) a magnetic field with alternating flux distribution is produced. At each instant the total magnetic flux (Ζ1, Ζ2) of the magnetic circuit is maintained to be constant through keeping a constant volume of the magnetic gap (1o) of the circuit. The armature (3), made of a ferromagnetic and coupled with the shaft of motor (4), is affected by the magnetic field and successive parts of the armature (3) are set in motion in a direction parallel to the magnetic field lines (11). In the method of producing mechanical energy of the rotating motor shaft (4) the total magnetic flux (ΖA, ΖB, ΖC, ΖD) in an individual magnetic circuit of the electromagnets (1A, 2A), (1B, 2B), (1C, 2C), (1D, 2D) is maintained to be constant thanks to operation within saturation range of the magnetization characteristic B=f(H) for the electromagnet cores (1A, 1B, 1C, 1D).

Description

Method of converting electrical energy into mechanical energy of rotating shaft and method of producing mechanical energy of rotating shaft

A method of converting electrical energy into mechanical energy of a rotating shaft and a method of producing mechanical energy of a rotating shaft by means of a magnetic field make the subject of this invention.

A method is known, how to convert electrical energy into mechanical energy of a rotating motor shaft, consisting in production of a magnetic field perpendicular to a direction of the shaft rotation with a direction of the magnetic field lines parallel to that of the shaft radius. An electric winding or a set of windings is placed in the magnetic field on the motor shaft and fed with electric current from a source of electrical energy to be converted. After initiating preliminary rotary motion of the winding on the motor shaft, a winding carrying a current perpendicular to the magnetic field lines is shifted and thus a rotational electromotive force is produced, which is necessary to force the winding on the motor shaft to rotate.

If a magnetic field is produced by electromagnets rather than permanent magnets, then a variable magnetic flux is produced due to a variable current flowing through an electromagnet winding or set of windings. Then, the magnetic flux is modulated by the moving winding and an electromotive force of transformation is produced apart from a rotational electromotive force. Magnitudes of both forces are proportional to an amount of electrical energy converted.

The phase of current flowing through a winding(s) is kept in step with the phase of shaft torque by a commutator so that rotational speed of the shaft is maintained constant.

In the known methods with concentric design of a motor a magnetic flux of alternatemagnitude and distribution is produced in the air gap between the poles of permanent magnets of a stator and the rotor poles.

The known methods of converting electrical energy into mechanical one consist in production of a rotational electromotive force and possibly an additional electromotive force of transformation provided that an electric conductor rotates in a magnetic field. The known methods can make use of the magnetization characteristic, which is a relation of magnetic induction vs. field intensity, i.e. B=f(H), only within its rising range rather than the saturation range.

The methods known to the trade are characterized by sluggish starting-up and retarding due to a large rotating mass.

Nature of this invention in its first version of the method of converting electrical energy depends on supplying an electric current from a source of energy to be converted into electromagnets windings to produce a magnetic field, the lines of which in the air gap are perpendicular to a ferromagnetic armature coupled with a rotary motor shaft and this magnetic field is used to move the armature in a direction parallel to the magnetic field lines in the gap.

Nature of this invention in its second version of the method depends on maintaining a constant value of total magnetic flux through its magnetic circuit at each instant by keeping a constant volume of the gap. Coupled with the motor shaft the ferromagnetic armature is affected by the magnetic field so as to set the successive sections of the armature in motion in a direction parallel to the magnetic field lines.

Nature of this invention in its third version of the method depends on maintaining a constant value of total magnetic flux-at each instant of period from switching the current on to switching it off-in the magnetic circuit of a single electromagnet by operating the electromagnets in the saturation section of the electromagnet core magnetization characteristic B=fiΗ). The ferromagnetic armature coupled with the motor shaft is affected by the magnetic field produced by the electromagnets so as to set the armature in motion in a direction parallel to the magnetic field lines.

In an embodiment of this invention, electrical energy is converted into mechanical one or vice versa while no rotary motion is employed. Therefore no rotational electromotive force is generated as the machine has no electric windings rotating in a magnetic field. The armature attracted by the electromagnet moves in a direction parallel to the magnetic field lines and this results in modulation of the magnetic flux due to a change in the width of gap. An electromotive force of transformation is induced in the electromagnet winding.

The invention is shown in more detail by means of an example presented in a drawing where Figure 1 diagrammatically presents a top view of a direct current motor employing two electromagnets with the front cover removed, Figure 2 diagrammatically presents a commutator which receives the current to the motor shown in Figure 1 , Figure 3 presents a longitudinal section of the electric motor with a single electromagnet, Figure 4 presents a cross-sectional view of the electric motor with a single electromagnet, Figure 5 presents a chart of magnetic flux value versus angle of rotation, Figure 6 presents a longitudinal section of an electric motor with electromagnet unit fixed to a common base; Figure 7 presents a power supply circuit diagram for individual electromagnet windings, and Figure 8 presents the current and flux waveforms for individual electromagnets.

The method of converting electrical energy into mechanical one by the motor shown in Figure 1 depends on alternately supplying the windings 2 with electrical energy in the form of current Iz to produce a magnetic field in the electromagnets 1_^2 which attract the common armature 3_^3 alternately within their working area. Thus, the armatures 3 are impelled to reciprocate in a direction parallel Jo the magnetic field lines JJ_. This motion is converted into the rotary motion of the shaft 4 by means of a link motion being the coupling component 5,5a. The electric machine shown in Figure 1 includes the electromagnets ] 2 mounted to a base. The magnetic core I of each electromagnet is a horseshoe- shaped bar with a winding wound in the middle of core. The end surfaces l_a of each core where magnetic poles N-S are located constitute sectors of a single plane P,P'. These ends la of the cores_ of both electromagnets 1,2 point towards and opposite one another. A rotary shaft 4 is mounted in its bearing in midway between both electromagnets 1_^2 so that its axis 7 is parallel to both planes P,P'. Each electromagnet 1_^2 is fitted with a T-shaped ferromagnetic armature 3, the horizontal section of which (horizontal bar of "T" letter) is parallel to the plane P,P'. Both armatures 3 are fixed with their T-letter vertical bars to the elliptic slotted lever 5 of the link motion 5,5a which is coupled with the shaft 4 to make the armature 3_^3 shared by both electromagnets ) 2. The slide 5a of the link motion is coupled with shaft 4 and fixed to the face of rotary shaft_4 at a distance_.! from the shaft axis 7.

As it is shown in Figure 2, one of the terminals 6 of the windings 2 is connected to the negative terminal "-ve" of power supply, and the other terminals_6 are connected to the emitter of p-n-p transistor T. The bases of both transistors T are connected to the commutator sectors 8, while the collectors of transistors T are connected through their resistors R with the slip-ring 9 of the commutator and to the positive terminal "+ve" of the power supply. The brush 10 fixed to the shaft 4 alternately connects the slip-ring 9 to one of the commutator sectors 8 during the shaft rotation. The direct current Iz is alternately fed from the power supply through the transistors T, which are controlled by the commutator, to the windings_2.This results in applying a voltage across the windings 2 of electromagnets to alternately attract the armature 3 by both electromagnets I and produce reciprocating motion of both armatures 3 and the slotted lever 5 of the link motion. Vectors of the velocities of the armature 3 are parallel to the magnetic field lines ϋ in the gap lo.

By lifting the slotted lever_5, the slide 5a of the link motion is impelled to move upward within the slotted lever 5 and along a circle of radius r, as it is fixed to the rotary shaft 4. Thus, reciprocating motion of the slotted lever 5 impels the slide 5a of the link motion to rotate, thereby causing rotation of the shaft 4.

The method of producing rotary motion of the motor shaft, as shown in Figures 3 and 4, depends on applying a direct current voltage Uz across the electromagnet 1_^2 to produce a magnetic field which rotates due to the rotation of the magnetic screen_5 that covers the electromagnet to some extent. Successive ferromagnetic parts of the armature_3_, affected by the magnetic field, are set in motion in a direction parallel to the magnetic field lines. Because the armature 3 is disc-shaped, successive sections along the armature periphery are set in motion towards the electromagnet 1_^2 so as to not rotate the armature 2. A constant volume of the air gap lo is maintained at each instant to result in the total magnetic flux Φ1,Φ2 through the magnetic circuit l,5,lo,3 being maintained constant. The armature motion mentioned above results in shaft rotation.

By replacing the electromagnet J 2 operated from a direct current voltage =Uz with a magnetized permanent magnet, the same effect is obtained, i.e. a rotating magnetic field is produced due to rotation of the magnetic screen 5 that covers the electromagnet to some extent. In consequence, successive sections along the periphery of armature 3 are set in motion towards the magnet so as to not rotate the armature. A constant volume of the air gap lo is maintained at each instant to result in the total magnetic flux Φ1,Φ2 being constant. Motion of the armature is converted into rotation of the motor shaft.

The motor includes the electromagnet .2 secured to the base 7. The electromagnet core 1 is in the form of two concentric cylinders joined with their bottoms so as to create U- letter shape in its cross-sectional view. Operated from the direct current voltage Uz is the winding 2 located between the cylinders of the core j_. The edges of the core cylinders, on which the poles of electromagnets are located, are sectors of the plane _P_ which is parallel to the base 7. The motor shaft 4 is supported by the slide bearing 6 in the base 7. Above the electromagnet ] 2 located is the magnetic screen 5 made of ferromagnetic material in the form of a semicircular plate with a concentric hole. The magnetic screen is welded on to the motor shaft 4 along the hole edges. The disc-shaped armature 3 of electromagnet is located above the screen. A bent part _10 of shaft 4 is supported by the slide bearing 8 seated on the other side of the armature_3 than that of the magnetic screen 5 so that the axes 10 and_9 of both shaft sections are at an acute angle α to one another. The armature 3 is inclined to the plane P at the same angle α.

By applying adirect current voltage Uz a magnetic flux is produced, which is divided into two portions. The first portion of magnetic flux ΦJ_ is confined by the magnetic screen 5 and the part of electromagnet 1,2 shielded by the screen 5. The second portion of magnetic flux Φ2 is confined by the armature 3 and the part of electromagnet } 2 not shielded by the screen 5.

As it is shown in Figure 3, the flux magnitude depends on an angular coordinate β of the point under consideration on the plane P. The angleβ is measured from the straight edge 1_3 of the screen 5 above which the point 15 (at the closest distance to the screen 5) of the armature 3 is located. The magnetic flux near the straight edge Jo, outside the screen 5, is always the lowest and it builds up according to linear law until an angle β = π is reached. Near the other part of the straight edge 13, connected with the point 14 of the armature 3, located at the furthest distance from the screen 5, there is a jump in the magnetic flux to reach its highest value under the screen_5 where it is maintained constant.

The first portion of magnetic flux Φl produces a force acting on the screen 5 in the axial direction. Moment of the above force is balanced by the shaft stiffness. The other portion of magnetic flux Φ2 produces a force acting on the armature 3 in its axial direction. As the moment of this force is unbalanced it results in motion of the point L5 (the lowest position of the disc) towards a point located on circumference of the armature 3 above that area of electromagnet ) 2, which is not shielded by the screen 5. This is the point, where the force producing an unbalanced moment is applied.

Due to synchronized motion of the armature and the screen, the configuration of the gap is the same at each phase of motion. A constant volume of the gap lo causes the total magnetic flux (Φl + Φ2) to be invariable with time whether or not the electromagnet core operates within the saturation range. It causes rotation of the bent part K)' of the motor shaft supported by the bearing 8, rotation of the non-bent part_4 and rotation of the screen 5. Due to rotation of the screen 5 there is a change of the point where the force attracting the point 15 in circumference of armature 3 is applied, through exposing new and new sections of the electromagnet 1_^2. Consequently, rotary motion of the shaft 4 and the screen_5 maintains itself and the moment produced by the other part of magnetic flux Φ2 remains unbalanced. Shown in Figure 3 the distribution of magnetic flux always remains constant during rotation of and rotates together with the screen 5_, and the total magnetic flux produced by the electromagnet 1,2, i.e. the sum of both magnetic flux portions (Φl + Φ2), is constant at any phase of motion. The magnetic screen 5 rotating together with the shaft acts as a magnetic commutator. Because of the constant magnetic flux produced in the motor, the electromagnet LJ2 can be replaced by an appropriately magnetized permanent magnet.

Due to_the lack of magnetic flux fluctuations, no forces are induced in the electromagnet winding_2. So, the motor does not convert electrical energy into mechanical one, but like the motor specified in the US patent no. 4155431 uses energy of nuclear spins of the core 1 ferromagnetic material.

In the method of producing rotary motion of the motor shaft, as shown in Figure 6, an alternating magnetic field is produced by means of the electromagnets 1A,2A. 1B,2B, 1C,2C, 1D,2D switched on in turn. Successive ferromagnetic sections located on the edge of ferromagnetic armature J3 successively approach to the successive electromagnets their motion being parallel to the magnetic field lines and therefore the armature 3 is not set in motion. The value of the total magnetic flux ΦA,ΦB in its magnetic circuit 1A, lp,3, lB-1^3, lC!o,3, lD,lg,3 is maintained constant at each instant from switching the current on to switching it off, in an individual electromagnet thanks to operation of the electromagnets !A,2A , 1B,2B , 1C,2C , 1D,2D within the saturation range of the magnetization characteristic B=f(H) for the electromagnet cores. Motion of the edge of armature 3_^ thanks to its coupling with the motor shaft 4, is converted into rotary motion of the motor shaft 4.

As shown in Figure 6, the motor has four electromagnets 1A,2A , 1B,2B , 1C,2C , 1D,2D, with one electromagnet being invisible. The cores A , LB , !C , ID are U-shaped or horseshoe-shaped bars and fixed to the base A with their bent sections. The electromagnets are evenly distributed in circumference so that each pair is located at the ends of a diameter. The winding 2A is wound onto the inner leg of the core LA, the winding 2B is wound onto the inner leg of the core JJB, the winding 2C is wound onto the inner leg of the core 1C, and the winding 2D is wound onto the inner leg of the core LD. The surfaces of ends la of all electromagnet cores LA, LB , 1C_. , IP where the magnetic poles N-S are located, are sectors of the plane _P. Above the ends J_a of the cores located is the disc-shaped armature 3which is shared by all electromagnets 1A,2A, 1B,2B , 1C,2C , 1D,2D . On its other side the armature 3 is equipped with the concentric bracket 3a which is pin-shaped and seated in the cylindrical recess 4a at the end of the shaft 4. The axis of the cylindrical recess 4a is inclined at an acute angle to the axis 7 of the shaft4.

As shown in Figure 7, the power supply source Uz is connected to the slip-rings 9^ and 9+. Fixed to the shaft 4_^ pairs of brushes K) and 10A transfer the current Iz from the slip-rings 9 and 9+ to the commutator sectors 19B and 19D. The current Iz flows from the positive terminal "+ve" of the power supply source Uz via slip-ring 9+, pair of brushes 10A, commutator sector 19B, third switching diode D , winding 2A, fourth switching diode D4, winding 2D, commutator sector 19D, pair of brushes J_0, slip-ring 9^ to the negative terminal of the power supply source Uz. During the shaft rotation by an angle of π/2 the pairs of brushes 10, 10A transfer the current Iz from the slip-rings 9^ and 9+ to the commutator sectors 19A and 19C and the current jz flows through fourth switching diode P winding 2D, first switching diode D_l, winding 2C, and the commutator sector 19D.

As shown in Figure 7, the successive electromagnets 1A,2A , 1B,2B , 1C,2C , 1D,2D are supplied with current every 1/4 of the period T. Each electromagnet operates over a time of 1/2 T to produce its magnetic field with its lines ϋ perpendicular to the plane P (as shown in Figure 1) The magnetic flux induced by this magnetic field is constant from switching an individual electromagnet on to switching it off The magnetic flux is constant for each electromagnet because the current Iz has been adjusted so as to maintain the ferromagnetic material of electromagnet core operating within the saturation range of the magnetization characteristic B=f(H) in situations where a maximum width of the air gap is obtained When the width of air gap decreases, the magnetic field strength in an electromagnet core increases abruptly The magnetic flux remains constant because the magnetic permeability μ_r of the core decreases as the magnetic field strength H increases, so that the magnitude φ = μ₀μrHS remains constant, where μ₀ - magnetic permeability of vacuum S - area of electromagnet core cross section, φ- magnetic flux in the magnetic circuit of electromagnet

By periodically energizing the successive electromagnets 1A,2A, 1B,2B, 1C,2C, 1D,2D, the magnetic field around the respective electromagnets grows and decays respectively and those parts of the armature 3 which are just above active electromagnets are attracted It allows the current to be kept in step by means of motion phases The attraction zone of the armature_3_ moves around a circle to result in motion of the successive section of the armature edge towards an active electromagnet 1A,2A, 1B,2B, 1C,2C, ID, 2D A section of the armature_3_ edge attracted towards the successive electromagnet 1A,2A, 1B,2B, 1C,2C, 1D,2D, moves in a direction parallel to the lines JJ_ of the magnetic field in the gap lo Attraction of successive sections of the armature edge causes the bracket 3a to move on lateral surface of a cone, the axis of rotation 7 of which is an axis of rotation of the shaft 4 Free end of the moving bracket 3a supported by bearing in the shaft_4 causes rotation of the shaft 4 on its axis 7

As shown in Figure 7, the commutator by adjusting the power supply phase to the motion phase alternately energizes the opposite electromagnets 1A,2A and 1C,2C, as well as 1B,2B and 1D,2D, respectively The power supply phases of both pairs of electromagnets 1A,2A,1C,2C and 1B,2B,1D,2D are shifted against one another by a shaft rotation angle of π/2 It results in simultaneous operation of two adjacent electromagnets Each electromagnet starts to attract the armature 3 when the width of gap lo is at its maximum and completes this cycle when the width of gap lo is at its minimum In situations where the system operates below the saturation range, the magnetic flux ΦA, ΦB, ΦC, ΦD in individual circuits increases to result in generation of an electromotive force in the respective winding and convert the electrical energy into mechanical one when the width of air gap lo is decreased

No rotational electromotive force is produced in the motor as it has no rotating electromagnetic components There is no an electromotive force of transformation either, which would be generated owing to magnetic flux modulation caused by movement of the armature_! in magnetic field This is due to the electromagnets 1A,2A, 1B,2B, 1C,2C, 1D,2D, operating within the saturation range of the magnetization characteristic B=f(H) Large changes in the magnetic field strength do not cause any changes in the magnetic flux within this range

Claims

1. A method of converting electrical energy into mechanical one of a rotating motor shaft where an electric current is supplied from a source of the electrical energy to be converted to at least one electromagnet winding to produce a magnetic field affecting a component of the motor coupled with its rotary shaft to result in the shaft rotation, and where the phase of flowing current is kept in step with the phase of torque, characterised in that the electric current (Iz) which is fed into the windings (2) of electromagnets producing the magnetic field, the lines (H) of which in the air gap (Jo) are perpendicular to the surface of ferromagnetic armature (3) coupled with the motor shaft (4), and where this magnetic field is employed to move the armature (3) in a direction parallel to the magnetic field lines (1 1) in the air gap (Jo).

2. A method of producing mechanical energy of a rotating shaft in a motor fitted with a single magnetic circuit where by rotating the rotor coupled with the shaft, a magnetic field with alternating flux distribution is produced to affect a component of the motor, which is coupled with its shaft so as to rotate the shaft, characterised in that maintaining a constant value of the total (3) in motion in a direction parallel to the magnetic field lines (11). magnetic flux (╬ª1,╬ª2) through its magnetic circuit (l,lo,3) at each instant by keeping a constant volume of the gap and where the ferromagnetic armature (3) coupled with the shaft of motor (4) is affected by the magnetic field so as to set the successive sections of the armature (3) in motion in a direction parallel to the magnetic field lines (11) in the air gap (lo).

3. A method of producing mechanical energy of a rotating motor shaft fitted with more than one electromagnetic circuit where a magnetic field with alternating flux distribution is produced to affect a component of the motor coupled with its shaft to result in the shaft rotation, and where the phase of flowing current is kept in step with the phase of torque, characterised in that the total magnetic flux ( ╬ªA, ╬ªB, ╬ªC, ╬ªD) in the magnetic circuit (lAJo,3), (1B,1Q,3), OClo ?), (1D,1Q,3,) being maintained constant at each instant from switching the current on to switching it off in an individual electromagnet thanks to operation of the electromagnets (1A,2A), (1B,2B), (1C,2C), (1D,2D) within saturation range of the magnetization characteristic B=f(H) for the electromagnet cores (LA, LB, 1Q, ID), and where the ferromagnetic armature 0) coupled with the shaft of motor (4) is affected by the magnetic field to set successive sections of the armature (3) coupled with the shaft of motor (4) is affected by the magnetic field to set successive sections of the armature (3) in motion in a direction parallelto the magnetic field lines (J _).