FR2474782A1 - CONVERTER GROUP COMPRISING A THREE-PHASE MOTOR AND A SYNCHRONOUS GENERATOR - Google Patents

Abstract

CONVERTER GROUP CONTAINING A THREE-PHASE MOTOR AND A SYNCHRONOUS GENERATOR OR ALTERNATOR. THIS CONVERTER GROUP IS REMARKABLE IN THAT THE SYNCHRONOUS MOTOR AND THE SYNCHRONOUS GENERATOR ARE MADE IN THE FORM OF A 2 SYNCHRONOUS MACHINE INCLUDING A COMMON 8 POLE WHEEL EXCITED WITHOUT BRUSHES AND, ON THE STATOR SIDE, TWO SEPARATE WINDINGS GALVANICALLY ONE OF THE WINDOWS. OTHER, THAT IS MOTOR WINDING 4 AND GENERATOR WINDING 6, AND IN THAT THE MOTOR WINDING, THREE-PHASE CURRENT SIDE IS CONNECTED TO A CURRENT CONVERTER 14 POWERED BY A DIRECT CURRENT SOURCE 20-22. APPLICATION TO THE REALIZATION OF NETWORK STABILIZERS, FREQUENCY CONVERTERS AND UNINTERRUPTED CURRENT POWER SUPPLIES.

Description

The present invention relates to a converter unit comprising a

  three-phase motor and a generator or

synchronous alternator.

  Such converter units are used as network stabilizers or frequency converters.

  quence, or even in electrical

  course. Network stabilizers are engine-generators

  which, on the generator side, feed a secondary network on the

  What are the devices connected with the use of large

  their and sensitive. Thanks to the engine-generator, the network

  terminal is completely separated from the primary network and now

  naked away from any disturbances that occur in it such as spikes, surges or sudden voltage drops. Thanks to the energy accumulated in the rotating masses, the secondary network is also

  protected from the effect of short interruptions of sec-

  in the primary network. As drive motors

  in the network stabilizers, one can use

  synchronous or asynchronous. The generators are, pre-

  ference of synchronous generators excited without brushes.

  If the primary and secondary frequencies are not equal

  between them, the engine-generator works in converts

  frequency, the different frequencies being obtained, for example, for the same speed of rotation of the motor and the generator, with different numbers of poles. It is also known to produce a difference in speed

  of rotation through gears or use of

  to use mixed systems, in which the difference in frequency is obtained, on the one hand, by means of different numbers of poles and, on the other hand, by means of an intermediate gear. If the secondary frequency is very close to the primary frequency, for example when going from

  at 60 Hz, it is necessary to provide, in the form of

  tion, which operates without gears, large numbers of

  poles which, like gears, have an adverse effect

  on the size, weight and price. In the

  frequency invertors also, preferably used,

  as drive motors, synchronous or asynchronous motors

  chrons. Moreover, frequency converters

  also try network stabilizer properties.

  A problematic point in converter groups

  known is that, in the event of a breakdown of the sector, the

  synchronous and asynchronous motors used as motors for

  dragging continue to operate as generators and can

  return considerable power to the primary network. The power thus returned must be taken together with the power to be supplied by the generator,

  on the energy accumulated in the rotating masses. This involves

  significantly increases the available soldering times

during a power failure.

  When power is restored to the mains, it is

  in particular in the case of asynchronous motors

  These are strong pulses of current in the primary network that can trigger upstream power circuit breakers. Moreover, especially in the case of synchronous motors, it is necessary to provide synchronization devices

  which only allow a circuit-back in a corner

of phases.

  In engine-generators intended to ensure a

  uninterrupted power supply, the drive motor

  must, in the event of a power failure, be powered by a battery

  crocheted. For such groups, therefore, DC motors are preferably used, in which the frequency of the secondary network is kept constant by

  control of the excitation independently of the voltage of the

  mentation and primary frequency. Because of the great time constants of the exciter, to get a good

  dynamics of regulation during the action of disturbed magnitudes

  In general, it is necessary to provide additional flywheels which, in particular, to the great powers, may have considerable masses and

  for which special bearings must be provided.

  The object of the invention is to create a converted group

  it can be used as a mains stabilizer or frequency converter, as well as to ensure uninterrupted power

  single-shell and brushless construction mode and pre-

  feeling a good dynamic of regulation, even without ruffles

additional inertia.

  For this purpose, according to the invention, the synchronous motor and the synchronous generator are made in the form of a machine comprising a brushless common polar wheel without brushes and, on the stator side, two galvanically separated windings.

  of each other, namely a motor winding and a motor

  generator bearing, and the motor winding is

  connected, three-phase current side, to a power converter

  powered by a DC power source.

  According to other advantageous features of the converter group according to the invention; the current converter is driven from the outside and its starting pulses are determined by the phase position of the voltage in the motor winding; the current converter is controlled according to the position of the polar wheel;

  the windings are made in the form of windings

  poor harmonic elements; - there is a harmonic filter with a circuit

  of resonance connected in parallel with the terminals of the winding-

engine;

  the harmonic filter is calculated in such a way as to

  a resonant frequency between five

  me and seventh harmonic frequencies;

  - the fundamental wave power of the harmonic filter

  This is calculated in such a way that the reactive power of the current converter is covered;

  - it is planned for the polar wheel a motor of lan-

  cement; - the current converter is connected, DC side, through a non-controlled network rectifier, to an AC network; - the rectifier is six or twelve pulses; the rectifier can be selectively connected to a battery. The converter unit according to the invention offers the advantage that, in the event of a mains failure, a return of power is impossible while, during the restoration of the current

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  sector, no uncontrolled current impulse

  Rait. The converter unit can be powered from batteries as needed in uninterrupted power supply installations. However, it is also possible to provide a power supply from a

  alternating current sector through an internal circuit

  of direct current, which can be supplied

  by means of non-controlled rectifiers.

  The invention will be better understood on reading the

  detailed description which follows and review the attached drawing which represents, as a non-limiting example, an embodiment. In this drawing - the single figure represents an assembly diagram of a

  converter group according to the invention.

  The synchronous machine "motor-generator" 2

  present, on the stator side, two windings 4, 6 galvanically separated

  trimmed from each other but are excited by a po-

  The pole wheel is mounted on a shaft 10 on which is also disposed the exciter 7 by which the pole wheel is excited without brushes. On the common tree

  it also acts as a launch engine 12.

  The motor winding 4 of the synchronous machine 2 is connected to a current converter 14. This converter

  current feeds the motor winding through the

  re of current converter rectifiers ordered 16.

  On the DC side, the power converter is powered

  from an alternating current network 18 through

  As far as necessary, for example in groups intended to provide an uninterrupted power supply, a battery 22 is also provided. The dc circuit

  can also be a DC sector. The redevelopment

  may be six pulses. An operation with twelve pulses is however also possible, for example by mounting in front of the rectifier of a three-phase separator transformer with two secondary isolated from each other, offset

  between them of 30 electric degrees. In this case, every second

  daire is loaded with a rectifier mounted in three-phase current bridge. With a twelve-pulse rectifier circuit, the primary network is largely kept free of current harmonics generated by the rectifier. Only the harmonics of eleventh and thirteenth orders, representing respectively 9% and 7.5% of the composition, remain unamortized.

basic wave.

  Since the rectifiers are uncontrolled, the DC link voltage is directly

  proportional to the supply network voltage.

  The dc direct circuit DC voltage is reconverted to a three-phase AC voltage by a bridge-mounted thyristor current converter

  three-phase current and which, on the three-phase current side, is connected

to the motor winding.

  The inverter operates as an inverter, through which the active power required for the operation of the synchronous machine is taken from the

DC circuit.

  The reactive power of control and switching ne-

  on the other hand, the power converter is

  by the synchronous machine. By setting the priming of thyroid

  ristors in relation to the voltage across the winding

  of the engine, it is possible to control the power consumption

  synchronous machine. This consumption is, for a constant motor voltage and a constant speed of rotation, practically proportional to the passing current

  in the DC intermediate circuit.

  The rotational speed regulation of the machine can be carried out in a known manner, as in thyristor-fed DC drives, by means of

  a rotational speed regulator circuit to which is connected

  company a current regulator circuit.

  The current regulator circuit establishes a limitation

  current acting dynamically for the protection of

  appears from the installation and offers the possibility of eliminating

  disruptive magnitudes by the load current of the generator. The regulation of the voltage of the machine is ensured by a transistorized voltage regulator 26, which receives its operating voltage, in part, from

  voltage across the motor winding and, in particular,

  tie, from the mains voltage. Reliable excitement

  of the machine is thus ensured in all circumstances.

  When calculating the motor winding of the synchronous machine, the additional load must be taken into account.

  by the reactive power of the

  as well as by the harmonics of the current.

  The current harmonics generated by the converts

  The filter circuits are preferably formed as tuned series resonant circuits, whose resonant frequency is between the fifth and seventh harmonic frequencies. These filters behave, below the resonant frequency, and in

  particular for the fundamental frequency, as a conden-

  sateur. Especially favorable conditions are obtained if the capacitor 25 is dimensioned in such a way that

  covers the reactive power of the power converter.

  With such a dimensioning, the motor winding 4 of the machine is discharged from the current harmonics as well as, to a large extent, the current deviated from the current converter, whereby a favorable influence is obtained.

  on performance. The yield can be further improved.

  due to the fact that the filtering capacitor 25 covers part of the idling excitation and, therefore,

  contributes to a dissipation of the power of the exciter.

  The harmonic content of the winding voltage

  4, which is reduced by the

  24, also ensures a reduction in the content of

  the voltage at the terminals of the winding of genera-

6.

  To avoid a reactive effect of the engine system on the generator system, it may also be advantageous to

  provide the polar wheel with a damping winding

  ble film effect. A reduction of trans-

  put can also be obtained by appropriate choice of peripheral dimensions of the coils in both systems

of windings.

  The machine "engine-generator" can be realized under

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  the shape of a machine with salient poles excited without brushes.

  In order to be able to suppress, for the piloting of converts

  In the vicinity of the stop, i.e. for low back-up, the forced switching devices that would normally be expected, a

launch engine 12.

  The launch engine can be an asynchronous engine.

  If only DC power is available, the motor of

  cement can also be realized in the form of an engine

  DC. Hybrid motors can also be used.

  hydraulic or pneumatic launch engines, if one has the corresponding actuating fluids. In a manner known per se, it is also possible to start the

  synchronous machine in an asynchronous mode.

  In operation, after the acceleration of the group, via the launch motor 12, to the vicinity of the nominal speed of rotation and excitation of the machine

  at nominal voltage, the thyristor firing of the converters

  current is tripped. For a constant flow in the synchronous machine, the current in the DC intermediate circuit corresponds to the power consumption

  active motor part. The power converter

  thus the active power necessary to maintain the speed of rotation, and this even for a variable power,

  by controlling the active current in the motor winding.

  The reactive power of control and switching necessary for the operation of the current converter is, on the other hand,

provided by the synchronous machine.

  The current converter 14 normally operates as a current converter controlled from the outside. The priming of the rectifiers can thus be carried out in the simplest manner as a function of the AC service voltage.

  that is, depending on the motor voltage.

  However, it is also possible to control the con-

  current converter in a known manner according to the position of the synchronous machine pole wheel, if during overcompensation of the fundamental wave power

  wants to obtain a more stable market of the machine.

  When power cuts, or collapse of the

  mains voltage below allowable values, the con-

  The current initiator is first controlled at the latching limit of an inverter. Automatic support without problems after the return of the mains current is thus possible if the speed of rotation has not been too much

greatly reduced.

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Claims (11)

  Converter unit comprising a three-phase motor and a synchronous generator or alternator, said group being characterized in that the synchronous motor and the synchronous generator are in the form of a synchronous machine (2) comprising a common pole wheel (8) excited brushless and, on the stator side, two coils galvanically separated from each other, namely a motor winding (4) and a generator winding (6), and in that the winding of   motor, three-phase current side, is connected to a converter   current source (14) supplied by a current source tinu (20; 22).   2. Converter unit according to claim 1,   characterized in that the current converter (14) is   lot by the outside while its priming pulses are determined by the phase position of the present voltage in the motor winding (4).   3. Converter unit according to claim 1,   characterized in that the current converter (14) is   batched according to the position of the polar wheel.   4. Converter unit according to any one of the   preceding claims, characterized in that the wraps   They are made in the form of windings that are poor in harmonics. 5. Converter unit according to any one of   preceding claims, characterized in that provision is made   a harmonic filter (24) with a resonance circuit connected in parallel with the terminals of the motor winding (4).   Converter unit according to claim 5,   characterized in that the harmonic filter is calculated to have a resonant frequency between   the fifth and seventh harmonic frequencies.   7. Converter unit according to any of the   Claims 5 to 6, characterized in that the fundamental wave power of the harmonic filter (24) is calculated in such a way that the reactive power of the converter of current is covered.   8. Converter unit according to any of the L474782   preceding claims, characterized in that it is provided   for the pole wheel a launch engine (12).   9. Converter unit according to claim 1,   characterized in that the current converter (14) is connected on the DC side via a non-controlled mains switch (20) to an AC mains (18). Converter unit according to Claim 9, characterized in that the rectifier (20) is six or twelve pulses.   Converter unit according to claim 9,   characterized in that the power converter (14) can   selectively connected to a battery (22>.