Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
  • H02P9/14—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field
  • H02P9/26—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices
  • H02P9/30—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices

Definitions

• the present invention relates to a rotating machine generating a sinusoidal current of frequency independent of its rotation speed.
• the invention consists in collecting the induced voltages of the conductors moving in a controlled magnetic field to generate a determined waveform.
• 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.
• 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).
• 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.
• 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 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;
• bipolar on-off switch for supplying the circuits with the battery and closing the feedback loop of the induced voltage
• FIG. 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;
• FIG. 3 and 4 are schematic representations of the rotary machine according to the invention.
• FIG. 5 is a schematic representation of the electronic device for feeding the machine according to the invention.
• FIG. 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.
• the sinusoidal current generating machine 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.
• 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;
• FIG. 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 .
• the device must generate a stable sine wave of power.
• 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.
• 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.
• an external low voltage source 14 such as a battery
• the machine is mechanically driven by an energy source 17 - a heat engine, a turbine, a wind turbine ...-
• 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.
• 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.
• 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 p ⁇ 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.
• control circuit 21 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_ ⁇ at the output of the oscillator 10, of the control voltage U co ⁇ 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.
• 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 co ⁇ 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 .
• 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.
• 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.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Control Of Ac Motors In General (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9426608

Family Applications (1)

Country Status (3)

Citations (6)

• 1992
  • 1992-02-13 FR FR9201620A patent/FR2687512A1/fr active Granted
• 1993
  • 1993-02-11 AU AU36351/93A patent/AU3635193A/en not_active Abandoned
  • 1993-02-11 WO PCT/FR1993/000144 patent/WO1993016521A1/fr active Application Filing

Patent Citations (6)

Non-Patent Citations (1)

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