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
  • H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
  • H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
  • H02P25/22—Multiple windings; Windings for more than three phases
• • 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
  • H02P1/00—Arrangements for starting electric motors or dynamo-electric converters
  • H02P1/16—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters
  • H02P1/46—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting an individual synchronous motor
  • H02P1/52—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting an individual synchronous motor by progressive increase of frequency of supply to motor
• • 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
  • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
  • H02P6/005—Arrangements for controlling doubly fed motors
• • 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
  • H02P2207/00—Indexing scheme relating to controlling arrangements characterised by the type of motor
  • H02P2207/05—Synchronous machines, e.g. with permanent magnets or DC excitation
• • 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
  • H02P2207/00—Indexing scheme relating to controlling arrangements characterised by the type of motor
  • H02P2207/07—Doubly fed machines receiving two supplies both on the stator only wherein the power supply is fed to different sets of stator windings or to rotor and stator windings
  • H02P2207/073—Doubly fed machines receiving two supplies both on the stator only wherein the power supply is fed to different sets of stator windings or to rotor and stator windings wherein only one converter is used, the other windings being supplied without converter, e.g. doubly-fed induction machines

Definitions

• the present invention relates to an assembly comprising a frequency converter, a synchronous electric machine and an associated switching system.
• the object of the invention is to be able to use a synchronous machine with permanent magnets by connecting it directly to the electrical network.
• the invention applies more particularly but not exclusively
• US 5,229,251 and UQS 5,528,804 disclose electrical machines having a wound rotor and a stator having a main electrical winding and an additional electric winding, the latter being fed via a frequency converter. These electrical machines are generators of "doubly fed" type with an asynchronous machine rotor and are very different from synchronous machines whose rotor comprises permanent magnets.
• the invention aims to further improve the synchronous machines and their power supply systems.
• the invention aims in particular to produce a synchronous machine whose performance is relatively unaffected by network voltage variations. electric or by load variations, and can be brought to a speed allowing it to be electrically connected to the power grid in a relatively simple and inexpensive way.
• the invention aims to meet this need and it achieves, in one of its aspects, through a set comprising:
• a synchronous electric machine having a rotor and a stator, and a switching system configured to electrically connect the synchronous electric machine to an electrical network
• stator comprising a main electrical winding connected to the switching system so as to be supplied directly by the network and an auxiliary electric winding connected to the frequency converter,
• the switching system being arranged to connect the main electrical winding to the network when the voltage, frequency and / or phase of the main electric winding are compatible with the mains power supply of the main winding.
• supplied by the network means the configuration in which the main electrical winding is directly connected to the electrical network, by the sole intermediary of the switching system.
• the synchronous machine can be started by modifying the frequency and the voltage applied to the auxiliary electric winding by the frequency converter, for example in a progressive manner.
• the motor is thus powered as a traditional synchronous machine during the start-up phase.
• the nominal power of the frequency converter may be between 1% and 50% of the nominal power of the synchronous machine, for example being equal to about 25% of the nominal power of the synchronous machine.
• the frequency converter used can thus provide only a reduced power, which reduces its cost and its size compared to a solution where the motor is supplied entirely by a drive.
• the switching system may have a configuration in which the auxiliary electric winding is electrically powered by the frequency converter when the main electric winding is connected to the power grid.
• the frequency converter can be configured to adjust the auxiliary electric winding current in the direct electrical axis of the machine and / or in the quadrature electrical axis of the machine when the main electrical winding is supplied by the network. .
• the main electric winding and the auxiliary electric winding can be wound so as to be electrically independent.
• the stator may have a plurality of notches and the main electrical winding and the auxiliary electric winding may be received in different notches. Alternatively, the main electric winding and the auxiliary electric winding are received at least in part in the same notches. Each slot receiving electrical conductors of the main electrical winding can thus receive electrical conductors of the auxiliary electric winding.
• the main electric winding and the auxiliary electric winding can be separated in the notch, which can create a leakage flow between said windings and thus facilitate the drive control.
• These leakage flows can also be created on the coil heads or at any other location, even outside the windings by auxiliary devices such as, but not limited to, ferrite cores.
• the auxiliary electric winding can be dimensioned so that it has a voltage compatible with that of the inverter supplied by the same network as the main electric winding.
• the synchronous machine and the frequency converter are for example polyphase, in particular three-phase.
• the voltage of the auxiliary electric winding is for example between 80% and 100% of the voltage of the main electric winding.
• the main electric winding and the auxiliary electric winding of the stator of the synchronous machine may comprise a different number of phases, the main electric winding being for example single-phase and the auxiliary electric winding being three-phase.
• the synchronous machine may comprise a rotor with permanent magnets. These permanent magnets are used to generate an induction flux in the air gap of the machine, said flux interacting with the stator in particular during operation in conditions nominal machine.
• the permanent magnets of the rotor are, for example, different from ignition magnets.
• the synchronous machine may be a radial induction flow machine or alternatively an axial induction flow machine with an internal or external rotor.
• the synchronous machine may be a synchro-reluctant machine, having a rotor with high saliency and having no or few magnets and being configured so that the stator field rotates at the stator as for a traditional synchronous machine.
• the nominal power of the synchronous machine can be arbitrary, being for example between IkW and several MW.
• the synchronous machine is preferably a synchronous machine requiring only a low torque to reach the synchronous speed on the network, for example: an air or refrigeration compressor, a pump or ventilation system whose loading is progressive, or a machine capable of starting empty and being loaded after starting, such as a grinder, a mixer, a chopper, a sieve or a kneader.
• the machine is loaded when placed in contact with a product intended to be ground, mixed, chopped, screened or kneaded, respectively.
• the machine can be connected to a load via a mechanical member such as a hydraulic or centrifugal coupler, a clutch for example.
• the synchronous machine can constitute a motor and the frequency converter can be configured to bring the voltage, the frequency and / or the phase of the main electric winding to values compatible with a supply of the main electric winding by the electrical network. .
• the voltage compatible with the power supply by the electrical network is for example between 95 and 105% of the network voltage.
• the frequency compatible with the power supply by the electrical network is for example that of the network + or - IHz.
• the phase compatible with the supply by the electrical network is + or - 10 ° with respect to the phase of the network.
• the synchronous machine is a generator that requires no or little electrical energy from the network to reach its nominal speed.
• Another aspect of the invention is a method of controlling a synchronous electric machine electrically connected to an electrical network via a switching system, in which:
• an electrical auxiliary winding of the stator of the machine is electrically connected to a frequency converter and the switching system is acted on to connect a main electrical winding of the stator of the synchronous machine to the electrical network when the voltage, frequency and / or phase of the main electric winding have values compatible with the power supply of the main winding by the network.
• the synchronous machine can be started by supplying the auxiliary electric winding with the frequency converter.
• the auxiliary electric winding of the stator may continue to be electrically powered by the frequency converter when the main electric winding is connected to the electrical network, the speed of rotation of the machine being compatible with the power supply of the electric winding. by the network.
• the method may include the step of acting on the frequency converter to adjust the induction flow in the direct electrical axis of the machine when the main electrical winding is supplied by the network.
• This adjustment can be made by injecting a current into the auxiliary electrical winding in the direct axis (in the sense of the Park transform) of the machine.
• This adjustment makes it possible to adjust the power factor of the machine and / or to make it work at its optimum operating point from the point of view of yield, for example, or of the reactive energy taken or supplied to the network.
• the method may also or alternatively include the step of acting on the frequency converter to adjust the current of the auxiliary electric winding in the quadrature electrical axis of the machine when the main winding is powered by the network.
• This adjustment makes it possible in particular to distribute the contributing currents to the torque of the machine in the main electric winding and the electrically auxiliary winding and to reduce its heating and / or improve the overall efficiency of the system.
• the contribution to currents in the direct or quadrature axis depends in particular on the capacitances of the frequency converter chosen.
• the invention further relates, in another of its aspects, to a method of using a synchronous electric machine, in which:
• the synchronous machine is started according to the above method, the synchronous machine operating at reduced torque or at a vacuum during this starting and,
• the synchronous machine is loaded after the main electrical winding of the stator of the synchronous machine has been connected to the electrical network.
• Such a method can make it possible to reduce the torque necessary for the acceleration of the synchronous machine to a speed of rotation compatible with the supply of the main winding by the network.
• the synchronous machine is for example a compressor, a pump or a ventilation system and, when starting the machine, the fluid undergoes a slight loss of load, and then once the main electrical winding of the stator of the synchronous machine connected the electrical network, the fluid path is changed so that the fluid output of the synchronous machine undergoes a greater pressure drop.
• FIG. 1 schematically represents an overall example according to the invention
• FIG. 2 is a view in axial section of a synchronous machine according to an example of implementation of the invention
• FIG. 3 is a cross-sectional view of a synchronous machine according to another embodiment of the invention.
• FIG. 4 schematically represents a method according to an embodiment of the invention.
• FIG. 1 shows an example of assembly 1 according to the invention.
• This set 1 comprises a synchronous machine 2, a frequency converter 3 and a switching system 4.
• the frequency converter 3 and the switching system 4 are both electrically connected to a network 100.
• This is for example a three-phase industrial electrical network delivering a voltage of 400 V between phases at a frequency of 50 Hz.
• the frequency of the electrical network can alternatively be 60 Hz and the voltage between phases can be different or equal to 400 V depending on the power grid considered.
• This voltage can correspond to the voltage of all the electrical networks of the world.
• FIGS. 2 and 3 synchronous machines 2 according to examples of implementation of the invention.
• the synchronous machine 2 may be a three-phase synchronous motor.
• the motor 2 for example has a nominal power of between IkW and several kW, or even several MW.
• the synchronous motor 2 may comprise any number of pairs of poles for example two, four, six or eight poles.
• the synchronous motor 2 extends along an axis of rotation X and comprises a stator
• stator 5 and the rotor 6 are concentric, the induction flux in the motor being radial, but the invention is not limited to such an example.
• the synchronous motor 2 is discoidal, the induction flux then being axial.
• the motor 2 has an internal rotor, the rotor 6 being surrounded by the stator 5, but in non-illustrated examples the motor has an external rotor.
• the motor 2 has a shaft 7, which can be monolithic.
• This shaft 7 is, in the example of Figure 2, mounted in the housing 8 of the machine on two bearings 9 carried by the front and rear flanges 10a and 10b. At least one of the front and rear flanges 10a and 10b may have a central opening 12 through which the shaft 7 extends outside the casing 8.
• the stator 5 comprises in the example described a packet of magnetic sheets 15, visible in Figure 3, on which are wound a main electric winding 16 and an auxiliary electric winding 17, independent.
• the magnetic sheet package 15 comprises a series of notches 18.
• the main and auxiliary electrical windings 16 and 17 may be received in different notches 18. Alternatively, some notches 18 only receive at a time the main electric winding 16 and the auxiliary winding 17. In another variant, each notch 18 receiving the main electric winding 16 also receives the auxiliary electric winding 17.
• shims 21 can separate the main electric winding 16 and the auxiliary electric winding 17.
• the main electrical winding 16 and the auxiliary electric winding 17 may be distributed windings or alternatively concentrated windings (that is to say wound on teeth).
• the ratio between the size of the auxiliary electric winding 17 and the size of the main electric winding 16 is for example between 10% and 100%, being in particular between 10% and 50%, better still between 25% and 40%.
• the rotor 6 of the synchronous motor 2 comprises in the example described permanent magnets 20 which may be magnets arranged on the surface, with or without poles between the magnets, or even buried magnets, arranged in the rotor radially or otherwise.
• the rotor 6 is for example flux concentration.
• the frequency converter 3 may have a rated power of between 1 and 50% of the nominal power of the synchronous motor 2.
• the nominal power of the frequency converter 3 is for example equal to about 25% of the nominal power of the synchronous motor 2.
• the frequency converter is for example housed in a housing fixed on the housing 8 of the synchronous motor 2
• the frequency converter is electrically powered by the electrical network 100, being electrically connected to the auxiliary winding 17 of the synchronous motor 2.
• the switching system 3 makes it possible to connect the main electric winding 16 of the stator 6 of the synchronous motor 2 to the electrical network 100.
• the switching system 5 comprises switches 19 which may be electromechanical relays or electronic components such as power transistors.
• the switching system may comprise a speed and / or position sensor measuring the speed of rotation of the motor and a control circuit controlling the switches 19 in the open or closed position depending on whether the electric winding main 16 has a voltage, a frequency and / or a phase close to the voltage, the frequency and / or the phase of the network 100.
• a speed and / or position sensor measuring the speed of rotation of the motor
• a control circuit controlling the switches 19 in the open or closed position depending on whether the electric winding main 16 has a voltage, a frequency and / or a phase close to the voltage, the frequency and / or the phase of the network 100.
• the auxiliary electric winding 17 of the stator 5 is supplied by the frequency converter 3.
• the switches 19 of the switching system 4 are open, so that the main electric winding 16 of the stator 5 is not electrically powered by the industrial network.
• the drive adjusts the current in the auxiliary electric winding 17 so that the voltage, the frequency and / or the phase of the main electric winding 16 is as close as possible to the voltage, the frequency and phase of the electrical network 100, being in particular equal to + or -2.5% of the voltage and the frequency and + or - 10 ° of the phase of the network.
• the switches 19 of the switching system 5 are automatically closed during a step 52 from which the main electrical winding 16 of the stator 5 of the synchronous motor 2 is connected to the network and thus electrically powered by the electrical network 100.
• the auxiliary electric winding 17 of the stator 5 of the synchronous motor 2 can remain powered by the frequency converter 3.
• the current delivered by the frequency converter 3 can be varied to the auxiliary electric winding 17 so as to optimize the operation of the synchronous motor 2, while the main electric winding 16 is connected to the electrical network 100. It is thus possible to improve the power factor of the synchronous motor and / or its efficiency.
• the induction flux of the machine can be adjusted in the direct axis (in the sense of the Park transform) by injecting a current into the auxiliary electric winding 17 in the electrical axis. direct.
• step 53 it is also possible or alternatively, during this step 53, to adjust the current of the auxiliary electric winding 17 in the electric axis in quadrature.
• the invention applies more particularly to synchronous machines requiring to achieve the nominal speed only a low torque, for example air compressors or refrigerators, pump or ventilation systems or machines likely to start empty. and being loaded after starting, such as grinders, mixers, choppers, sieves or kneaders.
• FIG. 5 shows an example of application of the invention to an air conditioning system 200 comprising a compressor 201 comprising a synchronous motor as described above and a loop 202 comprising a controllable valve 203.
• valve 203 When starting the synchronous motor, the valve 203 is open, so that the fluid flows in the loop 202 without significant pressure drop.
• a control unit which is for example integrated in the drive or is alternatively an independent component 205, detects that the voltage and the phase of the main electrical winding 16 are close to the voltage and the phase of the network, it triggers the switching system 4 which causes the supply of the main electrical winding of the stator of the synchronous machine by the electrical network then gives the closing order to the valve 203 so that the fluid circulates in the circuit provided .
• An assembly according to the invention can also be used to drive a rotating electrical machine, the synchronous motor driving said machine being connected thereto via a clutch in the disengaged state when starting the synchronous motor and then in the once engaged state. mains supply of the main winding carried out.
• An assembly according to the invention also applies to generators that do not need electrical energy to start up to their nominal speed, the inverter can be used initially to adjust the parameters of the machine in such a way that the main electric winding 16 has a voltage, a frequency and a phase close to the voltage, the frequency and the phase of the network 100, then, once the main winding is connected, to adjust the power factor parameters and machine performance.

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

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Applications Claiming Priority (2)

Publications (1)

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Cited By (3)

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Citations (8)

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• 2009
  • 2009-07-31 FR FR0903805A patent/FR2948833B1/fr not_active Expired - Fee Related
• 2010
  • 2010-07-29 EP EP10745420A patent/EP2460267A1/fr not_active Withdrawn
  • 2010-07-29 WO PCT/IB2010/053460 patent/WO2011013093A1/fr active Application Filing
  • 2010-07-29 CN CN2010800386295A patent/CN102484439A/zh active Pending

Patent Citations (8)

Non-Patent Citations (1)

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