Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
  • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
  • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
  • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
  • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M7/23—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only arranged for operation in parallel
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
  • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
  • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
  • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
  • H02M7/08—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode arranged for operation in parallel
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B63/00—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices
  • F02B63/04—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices for electric generators
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
  • H02M1/4208—Arrangements for improving power factor of AC input
  • H02M1/4283—Arrangements for improving power factor of AC input by adding a controlled rectifier in parallel to a first rectifier feeding a smoothing capacitor
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
  • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Definitions

• Electromechanical assembly comprising an alternator
• the present invention relates to the conversion of mechanical energy, obtained for example by means of a heat engine, into electrical energy.
• the invention relates to an electromechanical assembly comprising an alternator, in particular of high power, typically greater than or equal to 200 kW.
• An alternator comprises, in a manner known per se, an inductor winding, generally at the rotor, fed with direct current either by rings and brushes, or by an exciter, so as to generate, in an armature winding, generally at the stator, a AC voltage.
• a first solution is to rectify the AC voltage delivered by the alternator 10 by means of a simple diode bridge 11.
• the excitation of the rotor of the alternator by means of an exciter 12 or by a set consisting of rings and brushes is permanently adapted by a regulator 13, to maintain a constant DC voltage regardless of the speed of the driving member and the power to be delivered.
• a second solution illustrated in FIG. 2, consists of a rectification of the AC voltage delivered by the alternator 10 by means of an active rectifier 15 composed of an IGBT inverter controlled in pulse width modulation.
• the transistors 16 of the inverter are not controlled and the rectification performs the same as described for solution 1.
• the excitation current of the pole wheel is kept fixed and the transistors of the inverter are controlled to raise the voltage to the desired level.
• the publication WO 2012/110979 A1 describes in particular a means of arbitrating between the two types of operation, in order to minimize the level of overall losses of the system. This solution allows operation over a wide speed range, for example from 40% to 120% of the nominal speed, but nevertheless has the following drawbacks:
• a third solution illustrated in FIG. 3, consists in a rectification of the AC voltage delivered by the alternator 10 by means of a diode bridge 11 in association with an elevator chopper 17, as described in the application US2002 / 105819.
• the elevator chopper is not controlled and the straightening is performed identically to what is described for the first solution.
• the excitation current of the pole wheel is kept fixed and the elevator chopper is activated to raise the voltage to the desired level.
• This third solution allows operation over a wide speed range, for example 40%> to 120% of the nominal speed.
• it has the following drawbacks:
• the diodes of the rectifier bridge must be fast-recoverable because they are subjected to the high voltage dV / dt of the chopper; these fast recovery diodes are much more expensive than standard overlay diodes of the first solution;
• the switches of the elevator chopper can induce partial discharges which reduce the life of the winding of the alternator.
• an electromechanical assembly comprising:
• An elevator circuit connected via a filter to the output of the alternator and delivering a voltage to the DC bus.
• the rectifier is preferably a diode rectifier. These can be standard recovery time, including t rr (reverse recovery time) greater than or equal to 4 ⁇ 8.
• the filter may include a series inductor on each of the output phases.
• the value of the inductance is for example between 40 ⁇ and 80 ⁇ , in particular for a converter of 500kW connected to a DC bus of 650V, or between 120 ⁇ and 240 ⁇ , in particular for a converter 500kW connected to a DC bus of 1000V.
• the value of the inductances is chosen so that at the rated current, the voltage drop of the inductor is between 4% and 12% of the rated voltage of the alternator.
• the filter can have two capacities connecting each phase to the DC bus. These two abilities can be equal.
• the value of each capacity can be between 80 ⁇ and 300 ⁇ , especially for a 500kW converter connected to a 650V DC bus, or between 25 ⁇ and ⁇ , especially for a 500kW converter connected to a 1000V DC bus.
• each capacitor is chosen so that the cutoff frequency of the LC filter is between 1000Hz and 5000Hz.
• the capacitors are preferably connected to the upstream terminal of the inductances, that is to say to that which is connected to the alternator.
• the LC filter can be damped, for example by inserting a resistor in series with the capacitors.
• the boost circuit can be sized for a fraction of the maximum power to be transmitted, in particular less than 1 ⁇ 2 of the rated power, while the rectifier is sized for the maximum power to be transmitted.
• the rotor can be powered by an ac / dc converter.
• the regulator can act on the excitation current If of an exciter of the alternator.
• the excitation current is regulated so as to slave the DC bus voltage to a set value.
• the voltage of the alternator is rectified and raised by the boost circuit at a reference voltage Udc ref.
• the excitation current of the alternator can be adjusted so that the magnetic saturation level of the alternator does not exceed a predefined value, for example to have a saturation coefficient between 1.25 and 1.6.
• the elevator circuit preferably comprises an inverter.
• the inverter in the second mode of operation, can be controlled by a pulse width modulation (PWM) technique.
• PWM pulse width modulation
• the invention also relates to a method for generating electricity, in which the alternator is rotated by an electromechanical assembly according to the invention, as defined above.
• the first mode of operation can be selected when the speed of the alternator is preferably between 80% and 120% of its rated speed, and the second mode of operation is selected when the speed of the alternator is lower than that of the generator.
• the first mode preferably less than 80%> of its nominal speed.
• the second mode of operation can be selected when the power to be transmitted is lower than in the first mode.
• FIG. 4 is a diagram of an exemplary assembly according to the invention
• FIG. 5 represents an example of the variation of the power as a function of the speed of the rotation
• FIG. 6 illustrates an example of a regulation circuit
• Figure 7 is a timing diagram of the voltages of the inverter.
• the assembly 100 comprises, as illustrated in FIG. 1, a synchronous alternator 110 with wound rotor, the rotor of which is fed with direct current by an exciter 112 associated with a converter ac / dc rotating 119.
• a regulator of voltage 113 connected to the inductor winding of the exciter allows to regulate the DC bus voltage.
• a rectifier 111 consisting of diodes d1 to d6, in particular standard recovery time diodes (t rr ), rectifies the voltage of the alternator 110.
• This rectifier 11 1 is sized for the maximum power to be delivered.
• An elevator circuit 115 is connected to the alternator and the DC bus.
• This elevator circuit 115 is composed of a voltage inverter, for example an inverter with switching elements 11 to 16 constituted by IGBTs. The inverter 115 is controlled in pulse width modulation.
• An RLC filter connects the alternator 110 to the inverter 115.
• This filter comprises inductances 120 in series with the output phases of the alternator and capacitance pairs 130, 131 connected to the DC bus.
• the filter has six capacitances C1 to C6, connected in pairs at each phase.
• the elevator circuit 115 is sized for only a fraction of the maximum power to be delivered.
• the alternator is driven by a heat engine.
• the driving member is for example a wind turbine.
• the alternator is always wound rotor but the rotor is supplied with direct current by a set of rings and brushes.
• the AC alternator voltage is rectified by the diodes d1 to d6.
• the excitation current of the rotor If is permanently adapted by the regulator 113 to control the DC voltage Udc at a reference value Udc ref, which can be constant or variable.
• the regulator is for example a commercial regulator such as the reference D510 Leroy Somer company. Only a non-dimensional residual current flows through the switching elements 11 to 16 of the inverter. This mode of operation is preferably used in a zone B of the power / speed plane where the excitation current If of the rotor necessary to reach the desired DC voltage does not lead to a saturation of the magnetic circuit of the alternator. This zone of the power / speed plan is located, as can be seen in FIG. 5, where the power to be supplied is the highest.
• a second mode of operation preferably used at the lowest speeds, corresponding to the zone A in FIG. 5, the voltage of the alternator is rectified and raised by the inverter to the reference voltage Udc ref.
• the rotor excitation current is set so that the saturation level of the alternator does not exceed a certain defined value in order, among other things, to minimize the losses, for example to maintain a coefficient of saturation less than 1.25.
• the filter consisting of inductors 120 and capacitors C1 to C6 strongly attenuates the Vau, Vav, Vaw points the harmonics of the voltages Viu, Viv, Viw of the inverter in differential mode and in common mode.
• the body driving the alternator can only deliver a portion of its maximum power, which makes it possible to dimension the inverter, the inductors and the capacitors only. at a fraction of the nominal power, for example 1 ⁇ 2 of the rated power for a generator whose power of the heat engine decreases in N 3 .
• the reference d, q used is an orthonormal reference rotating at the frequency of the fundamental voltage of the alternator.
• the fictitious currents id, iq are obtained after applying a three-phase / two-phase transformation followed by a rotation of angle ⁇ to the three currents Iiu, Iiv, Iiw.
• the angle ⁇ is chosen such that a change in the value of the current iq acts only on the active power input of the inverter and a change in the value of the current id acts only on the reactive power.
• the value of the DC bus voltage is regulated at the reference value Udc ref by a PID (Proportional Integral Differential) type corrector 201 whose output constitutes the current setpoint iq_ref.
• PID Proportional Integral Differential
• the current setpoint id ref is chosen for example to minimize the losses of the alternator as described in the publication WO 2012/110979 A1.
• Two correctors PI Proportional Integral 202 and 203 make it possible to enslave the currents id and iq with the respective instructions id ref and iq_ref.
• the output of these two current regulators represents, in the rotating reference, the 2 orthonormal components Vd, Vq of the voltage vector to be applied to the input of the inverter.
• the condition on the angle ⁇ quoted above is fulfilled when the voltage Vd is equal to 0.
• the correctors PI 204 and I (Integral) 205 act as a PLL loop (phase locked loop). They enslave the voltage Vd to 0 and allow to define the angle ⁇ .
• the “Modulation” block defines the closing and opening times of the switching elements of each arm of the inverter, according to a known Pulse Width Modulation (PWM) method.
• PWM Pulse Width Modulation
• the technique chosen is a PWM pulse width modulation with fixed modulation frequency, where only 2 of the 3 arms of the inverter switch at each switching period, as illustrated in FIG.
• the inverter that does not switch is, for example, the one whose absolute value of the current is the highest of the 3 arms in order to minimize the losses of the inverter.
• the cyclic ratios of the two switching phases depend on the values Vd_ref, Vq_ref, the angle ⁇ and the voltage Udc, as illustrated in FIG. 7.
• the invention is not limited to the example which has just been described.
• the diode bridge 111 can be replaced by a thyristor bridge or a mixed bridge.
• the inverter can be replaced by a chopper.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Control Of Eletrric Generators (AREA)
• Rectifiers (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=53879563

Family Applications (1)

Country Status (5)

Cited By (2)

Families Citing this family (5)

Family Cites Families (12)

• 2015
  • 2015-03-05 FR FR1551839A patent/FR3033458B1/fr active Active
• 2016
  • 2016-03-02 US US15/554,455 patent/US10355616B2/en active Active
  • 2016-03-02 CN CN201680013926.1A patent/CN107431442A/zh active Pending
  • 2016-03-02 WO PCT/EP2016/054475 patent/WO2016139277A1/fr active Application Filing
  • 2016-03-02 EP EP16707758.5A patent/EP3266101A1/fr not_active Withdrawn

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