WO1993016521A1

WO1993016521A1 - Rotary machine generating a sinusoidal current with a rotation speed-independent frequency

Info

Publication number: WO1993016521A1
Application number: PCT/FR1993/000144
Authority: WO
Inventors: Jean Paul Aubry
Original assignee: Jean Paul Aubry
Priority date: 1992-02-13
Filing date: 1993-02-11
Publication date: 1993-08-19
Also published as: AU3635193A; FR2687512B1; FR2687512A1

Abstract

The present invention relates to a rotary machine generating a sinusoidal current, made with laminated metal sheets with low hysteresis and rotationally driven by a mechanical energy source, supplied by an electronic device which is comprised of: a sinusoidal reference oscillator (10) delivering a pilot voltage (Upil) of constant frequency; a comparator (25) comparing the voltage (Upil) with the induced voltage (Uind); a sinusoidal power inverter (11) supplied by the voltage (Uind) and delivering a control voltage (Ucom); a phase-shifter (12) making (Uind) in phase with (Ucom); a start-up circuit (15) supplied by a battery (14), delivering a current (Iaux) to an auxiliary winding (16) in phase with (Uind); a bipolar on-off switch (18); a low voltage supply (20) from (Uind).

Description

ROTATING MACHINE

SINUSOIDAL CURRENT GENERATOR

INDEPENDENT FREQUENCY OF ITS ROTATION SPEED

The present invention relates to a rotating machine generating a sinusoidal current of frequency independent of its rotation speed.

Since a conductor moving in a magnetic field B is the seat of an induced electromotive force e proportional to its speed v of displacement, its length 1 and the intensity B of the magnetic field: e = v. 1. B if the magnetic field is sinusoidal, this electromotive force will also be sinusoidal.

The invention consists in collecting the induced voltages of the conductors moving in a controlled magnetic field to generate a determined waveform. In a rotary DC machine whose collector is with blades, the brushes rub on these blades collecting the current of the conductors placed in front of their respective pole. The assembly constituted by the collector and the brushes acts as a current rectifier but above all as a space collector. When the machine operates as a generator (dynamo), the voltage U appearing at the terminals of the machine can be represented, as a function of the intensity and the direction of the magnetic induction B, by a straight line passing through the origin, the slope varies with the rotational speed n of the armature, for a given machine (Figure 1). FIG. 2 represents the induced voltage U as a function of a sinusoidal magnetic induction B = B sin Ωt, for different values of the speed of rotation n. We see that it is possible to obtain a voltage sinusoidal across the machine, of constant frequency f, such that f =

2 π independently of its rotation speed n, which fixes only the maximum amplitude of this induced voltage. The object of the present invention is to produce a rotating machine producing a sinusoidal electric voltage of constant frequency independent of its speed of rotation, by controlling the magnetic field created by the magnetizing coils of the machine.

For this, the object of the invention is a rotary machine generating sinusoidal current made of laminated metal sheets with low hysteresis, powered by an electronic device comprising the following circuits:

- a reference sinusoidal oscillator ^* delivering a pilot voltage at constant frequency;

a comparator receiving on the one hand said pilot voltage after adjusting its setpoint level and on the other hand a signal for measuring the induced voltage;

- a sinusoidal inverter supplied with power from the induced voltage and delivering a control voltage; - a starting circuit powered by a battery and delivering an excitation current to an auxiliary winding in phase with the induced voltage, until the latter reaches its set value;

- a bipolar on-off switch for supplying the circuits with the battery and closing the feedback loop of the induced voltage;

- a low voltage supply from the induced voltage. Other characteristics and advantages of the invention will appear on reading the following description of a particular embodiment, said description being made in relation to the attached drawings in which:

- Figure 1 is the curve of the voltage induced in the machine, as a function of the magnetic field for two rotational speeds;

- Figure 2 is the curve of the voltage induced in the machine, as a function of time, as a function of a magnetic field B and of the speed of rotation n of the armature, for two speeds of rotation;

- Figures 3 and 4 are schematic representations of the rotary machine according to the invention;

- Figure 5 is a schematic representation of the electronic device for feeding the machine according to the invention;

- Figure 6 is the representation as a function of time of the different voltages and magnetic fields involved in the electronic device;

FIG. 7 is an electrical diagram of the adapted phase shifter of the electronic device, and

- Figure 8 is a graphical representation of the currents and voltages across the components of the phase shifter. The elements bearing the same references in the different figures fulfill the same functions for the same results. The sinusoidal current generating machine according to the invention comprises a magnetic circuit with its inductor winding with independent excitation, and an armature winding. Figure 3 is a schematic representation of an alternative embodiment for which the inductor winding is fixed and the armature winding rotating. The stator 1, bipolar in FIG. 3, comprises a magnetizing excitation coil 2 and the rotor 3, placed at the center of the stator 1, comprises an armature coil 4 housed in the notches 5 regularly distributed on its periphery. The collector 6 is a cylinder centered on the axis of the rotor 3. A source of mechanical energy drives the shaft in rotation and the armature winding 4 is connected to an electric charge, then traversed by a current I. For operate with a sinusoidal magnetic field, the machine is produced according to the techniques of alternating current collector machines and in particular is constructed entirely of laminated sheets with low hysteresis whose quality - losses measured in Watt / kilogram - sets the maximum of the field magnetic obtained.

Each pole 7 comprises a coil 2 having a number of magnetizing turns such that the excitation voltage of the machine, U _exc , is expressed in Volts by Boucherot's formula:

Uexc = ⁴ ^'44 BSNF (I) where B is the magnetic field in Tesla; S is the surface of the coil in m ² ; N is the number of turns per coil;

F is the frequency of the voltage in Hertz. The parameters S, N. and F being constant, the relation (I) becomes U _exc = KB, with K = constant. This shows that the control of the excitation voltage U _exc is sufficient to be master of the magnetic induction B, therefore of the induced voltage Ui _ncj . Figure 4 is a schematic representation of a second version, with electronic collector, for which the magnetic poles 7 and the winding inductor 2 are at the rotor and rotate in the center of a stator comprising the armature winding 4. The slip rings 8 allow the current to be supplied to the poles and the function of the collector is ensured by an angular encoder 9 mounted on the shaft poles 6 which control, through a logic circuit, a set of electronic relays connected at the same points as the collector blades in an armature winding. The electronic collector increases the life of the machine by limiting mechanical wear and improves the dynamic characteristics by eliminating brush-collector friction, among other advantages. The rotary machine according to the invention is connected to an electronic device having the following characteristics, since the control of the machine is only carried out by controlling the excitation voltage U _exc .

First, the device must generate a stable sine wave of power. For this, the electronic device comprises, as shown in FIG. 5, a reference sinusoidal oscillator 10 with high stability and a sinusoidal inverter 11. Then, it must block all the possibilities of operation in direct current, as well as, on the one hand allow autonomous operation of the machine, the induced voltage V ± n _d taken from the terminals of the armature which must supply said electronic device, and on the other hand consume the minimum of reactive energy on the induced voltage. For these last three reasons, the device comprises a suitable power phase shifter 12, direct current rejector.

The device must also keep the induced voltage Ui _nc j constant whatever the terminal load of the machine and its speed of rotation in the normal operating range. To this end, the electronic device is provided with a feedback loop 13 with the induced voltage Ui _n d. Finally, it must allow the starting of the autonomous operation of the machine using only an external low voltage source 14, such as a battery, outside 14 and therefore comprises a starting circuit 15 supplying an auxiliary winding 16. The machine is mechanically driven by an energy source 17 - a heat engine, a turbine, a wind turbine ...- At the start, a bipolar on / off switch 18 is toggled in order firstly to authorize the supply by the battery 14 various electronic circuits making up the device and, on the other hand, closing a return loop 19 of the induced voltage taken from the terminals of the machine. A low-voltage supply circuit 20 receiving as input the induced voltage Ui _{n (} j which is zero at the start, delivers at output to a control circuit 21 a signal indicating the absence of voltage at the terminals of the machine. The circuit control 21 then authorizes the reference sinusoidal oscillator 10 to drive, through a 90 ° phase shifter 22, a low voltage inverter 23 delivering an excitation current Iaux ^{to the} auxiliary winding 16 after adaptation of the auxiliary coil by a circuit 32 making the impedance of this coil only real. This auxiliary winding 16, by supplying the reactive energy of the magnetic field is intended to create an alternating magnetic field in the machine, such that the induced voltage Ui _nc j is no longer zero. armature conductors then become the seat of electromotive forces collected by the collector. The induced voltage is applied to a power supply circuit 24 intended to supply the sine wave inverter 11. The latter delivers a so-called control voltage U _com which is in phase with the induced voltage Ui _nc j. The phase-shifter circuit 12 must phase-shift this control voltage U _com by 90 ° so that the magnetic field then obtained, which is by definition phase-shifted by 90 ° behind the excitation voltage of the field coil 2, is in phase with the magnetic field produced by the starting winding 16 and thus comes to reinforce its amplitude. This increase in the magnetic field leads to an increase in the induced voltage. When this voltage Ui _nd , taken from the return loop 19 and applied to the low-voltage supply circuit 20 reaches a predetermined value sufficient to self-supply the machine, the control circuit 21 stops the start-up process. This start-up process can also be stopped by the control circuit when the initially scheduled time is exceeded, signaling a fault.

Consequently, the supply of the electronic circuits of the device is no longer from the battery 14, but from the low voltage supply 20 which receives the induced voltage U _nc j after reduction by a voltage step-down 30. L reference sinusoidal oscillator 10 sends a reference signal called pilot voltage,? a comparator circuit 25 after adjustment of the setpoint level by a circuit 26. This comparator 25 also receives a signal for measuring the induced voltage Ui _nd , after reduction of its value by a voltage step-down circuit 27 in FIG. 5 , and then sends a signal to the inverter 11 such that the induced voltage Ui _nc j copies the voltage pϋ to within an amplitude scale factor. So the machine rotating according to the invention produces a sinusoidal induced voltage of constant frequency independent of its speed of rotation by controlling the excitation voltage creating the magnetic field prevailing in the machine.

When the induced voltage is greater than the set value, the control circuit 21 operates via a control circuit 29 and a selector 28 placed at the terminals of the machine, to authorize the supply of the supply network. distribution.

FIG. 6 is the representation as a function of time of the pilot voltage Up_ι at the output of the oscillator 10, of the control voltage U _coπι at the output of the inverter 11, of the excitation voltage U _exc at the output of the phase shifter 12, of the magnetic field created by U _exc , of the induced voltage O_ { _{n (} _ at the terminals of the machine, of the voltage U _aux in the auxiliary starting winding 16 which is in quadrature with the excitation current Ia x which causes the magnetic field B in the winding 16. We note the importance of the phases of the signals for starting the machine and the action of the adapted phase shifter 12 which allows the induced voltage Uj_ _n d to be brought into phase with the voltage of U _{com control} , thereby simplifying power supplies and improving the overall power factor.

The role of the adapted phase shifter 12 is to supply the reactive energy of the magnetic field, to block a possible direct current component and 'to introduce a phase shift such as the induced voltage Uind' ^{due to the} displacements of the armature winding 4 in the magnetic field. created by the inductor winding 2, ie in phase with the output voltage U _com of the inverter 11. This synchronization improves the overall electrical characteristics by reducing the capacities tanks and simplifies power supply. Figure 7 is an electrical diagram of the phase shifter 12 which consists of an inductance Li in parallel with the control voltage U _coπι at the output of the inverter 11, with a capacity C ^ in parallel with the inductor winding 2 therefore with the excitation voltage U _exc and a second capacitance C2 in series with the capacitance C ^ and connected to the terminal of the inductance Li receiving the current I om entering the phase shifter. The equivalent electrical circuit of the inductor 2 winding is composed of an inductance L in parallel with a resistor R representing the magnetic losses. The excitation current Iexc flowing through the inductor winding 2 is equal to the sum of the currents II and IR flowing respectively through the inductance L and the resistance R:

->

Iexc = I ⁺ the current IR being in phase with the excitation voltage U _exc and current II being in rear quadrature with said voltage U _exc .

The current le supplied by the capacitor Ci, in parallel with said voltage U _exc is in front quadrature with said voltage U _e χc ^and I ^e current I crossing the capacitor C2 is equal to:

^{> =} lL + lR ^{> +} Ic ^ The voltage U across said capacitance C2 is in quadrature with respect to the current I and Uç is calculated such that:

^U C2 ^{+ u} exc = U _com , Ucom being in phase with the current I - In addition, this capacity C2 blocks the direct current. Inductance i provides the residual reactive component so that the current I _com entering the phase shifter is in phase with the control voltage U _com . FIG. 8 is a graphic representation of the currents and voltages at the terminals of the elements of the phase shifter. It can be noted that, whatever the value chosen for the control voltage U _com , the product U _COIn x Icom will be equal to the product U _exc x IR, in other words that only real energy is consumed, the magnetic losses being linked to the quality of the sheets making up the machine according to the invention. Thus, in normal operation, the machine according to the invention transforms the mechanical energy supplied by the drive motor into alternating sinusoidal electrical energy, of constant frequency equal to that of the reference sinusoidal oscillator and of constant voltage, independent of the machine drive speed in the normal operating range.

The passage of the on-off bipolar switch to the off position interrupts the self-supply of the machine, therefore the electrical production, even if the mechanical drive is maintained.

Claims

1. Rotating machine generating sinusoidal current comprising a magnetic circuit with its inductor winding with independent excitation and an armature winding, made of laminated metal sheets with low hysteresis and rotated by a source of mechanical energy, said machine being supplied by an electronic device, characterized in that said device comprises the following circuits: - a reference sinusoidal oscillator (10) delivering a pilot voltage (Upϋ) at constant frequency;

- a comparator (25) receiving on the one hand said pilot voltage (Upii) after adjusting its setpoint level by a circuit (26) and on the other hand by means of a feedback loop (13) a measurement signal induced voltage (Ui _nc j);

- a sinusoidal inverter (11) of power supplied by a power supply (24) from the induced voltage (i _n d) and delivering a control voltage (U _coπι );

- a suitable phase shifter (12) introducing a phase shift such that the induced voltage (i _n d) is in phase with the control voltage (U _com );

- a starting circuit (15) supplied by an independent low voltage source (14) delivering an excitation current (I _a ux) ^{to an} auxiliary winding (16), in phase with the induced voltage (i _nc j), up to 'in that said voltage (Ui _nc j) reaches its set value;

- an on-off bipolar switch (18) authorizing the supply of said electronic circuits of the device by the low voltage source (14) and the closing of the feedback loop (19) of the induced voltage (Uj. _n a); - a low voltage supply (20) from the induced voltage, supplying the electronic circuits of the device after the start-up phase.

2. Rotating machine according to claim l, characterized in that the adapted phase shifter (12) consists of an inductor (L) in parallel with the control voltage (U _coπι ) at the output of the inverter (11), d '' a capacity (Ci) in parallel with the field winding (2) and a capacity (C ₂ ) in series with the capacity (Ci) and connected to the terminal of the inductor (Li), receiving the current (Icom ) entering the phase shifter, intended to block any direct current.

3. Rotating machine according to claim 1, characterized in that the starting circuit (15) consists of a 90 ° phase-shifter (22) connected to the reference oscillator (10), a control circuit (21) connected to the phase shifter (22) and to the low voltage supply (20), of a low voltage inverter (23) connected to the control circuit (21) and delivering the excitation voltage (U _aux ) to the winding auxiliary (16), after compensation for cosΦ by a circuit (32).

4. Rotating machine according to one of the preceding claims, characterized in that a disconnector (28), placed at the terminals of the machine, and actuated by a control circuit (29) controlled by the control circuit (21), authorizes supply to the distribution network.

5. Rotating machine according to one of the preceding claims, characterized. in that the field winding (2) and the auxiliary winding (16) arranged on the stator (1) of the magnetic circuit and the winding armature (4) is housed in the notches (5) of the rotor (3).

6. Rotating machine according to one of claims 1 to 5, characterized in that the induction winding (2) and the auxiliary winding (16) are housed on the rotor (3) and rotate in the center of the stator (1) comprising the armature winding (4), with an electronic collector mounted on the rotor shaft (δ).