Note: Descriptions are shown in the official language in which they were submitted.
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Modular inverter bay and control method for same for a set of electric
machines with no position sensors
The present invention relates to the field of electrical systems for the
control of electric machines with which an aircraft is equipped. More
specifically, it concerns a modular inverter bay and control method intended
for an aircraft comprising a set of electric machines equipped with position
sensors.
An aircraft generally comprises multiple electric machines distributed
throughout the aircraft for fulfilling a set of diverse tasks. Known for
example
are electric machines dedicated to starting up a propulsion turbine, to an air
conditioning system for the cabin of the aircraft, or dedicated to the
operation
of the flight control surfaces of the aircraft. For these tasks, DC,
asynchronous, or synchronous, triphase, hexaphase or more generally,
polyphase electric machines are notably used. These electric machines
consume electrical power available on the onboard network of the aircraft,
and for example supplied by a generator linked to a turbine or supplied by an
airport network while the aircraft is on the ground.
It is known that it is essential to have reliable information on the
position of the rotor of the electric machine. Any measurement error
regarding the position significantly increases electrical losses. Typically,
an
error of less than 5% in the actual position is generally sought, the impacts
on the machine being considered to be acceptable (an adverse effect on
mass linked to machine oversizing, additional costs, notably for cooling,
etc...). The electric machines implemented on board an aircraft exhibit high
rotational speeds, of the order of 10,000 to 50,000 rpm, making it necessary
to have information on the position of the high-frequency rotor, typically of
the
order of 8 to 40 kHz. Many techniques exist for evaluating the position of the
rotor. A variety of sensors are known ensuring a physical measurement of
the position, calculating means also exist allowing this position to be
evaluated as a function of the voltages and currents measured in each of the
phases of the machine.
In a conventional electrical architecture of an aircraft, each electric
machine possesses one or more inverters linked to the onboard network
which shapes the signal supplying power to each of the phases in
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accordance with the requirements of the machine. When the electric machine
is not equipped with position sensors, a widespread conventional method
implements a position estimator such as a Kalman filter. This estimator is
based on phase currents flowing in the machine as well as phase-neutral
voltages applied to the machine. Figure 1 illustrates the principle of this
position estimator in the case of an electric machine 11, supplied with power
by a sole inverter 10. The three phase currents (in this case a triphase
machine) are denoted by ia, ib, ic; the three phase-neutral voltages are
denoted by Va, Vb, V. The three objects denoted by A correspond to three
sensors respectively measuring the currents ia, ib, ic. The voltage VDC is the
input voltage of the inverter, or DC bus voltage at the input of the inverter.
By measuring the currents and voltages, the estimator allows the rotor
position 80 and the rotor rotational speed wo of the electric machine to be
determined using a function of the type:
(00, coo) = f (ia, ib, ic, Va, Vb, Vc)
Various known functions exist, using a Kalman filter or other
techniques, allowing this estimation of position and speed. These known
techniques are not covered again here in detail.
At this stage it is appropriate to mention that the present document
only makes reference to phase currents and phase-neutral voltages, but that
these generic designations refer more broadly:
- for phase-neutral voltages:
o to phase-phase voltages,
O to Park transformation vd-vq voltages,
o to PWM Da, Db, Dc duty cycles,
o to PWM duty cycles after Dq-Dd Park transformation,
o or using any other transformation equivalent to a change of
reference frame (for example Concordia)
- for phase currents, to Park transformation id-iq currents, or using
any other transformation equivalent to a change of reference
frame, for example Concordia.
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Figures 2a and 2b illustrate the principle of the estimation of position in
the case in which an electric machine is supplied with power by multiple
inverters, for example a number N of inverters. In a first known architecture,
the inverters are connected in parallel by generally adding an inductance at
the output of each bridge leg of the inverters, or the inverters can be
coupled
by a coupling inductor as shown in Figure 2a. As previously, ia, ib, Ic, Va,
Vb
and Vc represent the phase currents and the phase-neutral voltages of the
machine. The phase currents and the phase voltages at the output of one of
the N inverters, denoted by k, are denoted respectively by ka i v v ., .kb,
.kc, ka, . kb
and Vkc.
The connection of the inverters in parallel leads, for the phase
currents, to:
ia = Eika, ib = Eikb, ic = Eikc
k=1 k=1
which can be generally expressed as: iabc =Iikabc;
k=i
and for the phase-neutral voltages, it can be shown that:
N \ (N \ I N
Va = EVka IN, Vb = E Vkb IN, Vc = E Vkc IN
k=1 k=1
(N
which can be generally expressed as: Vabc = IVkabc IN.
Oc=1
In a second known architecture shown in Figure 2b, the machine
comprises multiple sub-machines, each one being supplied with power by a
dedicated inverter. The phase currents and phase-neutral voltages of the N
inverters are denoted as in the parallel architecture described previously,
and
as shown in Figure 2b.
In a known manner, a machine comprising N sub-machines can be
modeled by simple machine; the phase currents and phase-neutral voltages
then being respectively determined by the following relationships:
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iabc =likabc , and Vabc 1Vkabc /AT. (i)
k=1 k=1
Both architectures therefore result in the same equations, the
equations (i) above. To determine the rotor position of the machine, the
position estimator previously described therefore needs to know either:
- The phase currents and the phase-neutral voltages at the input of the
machine, i.e. ia, ib, ic, Va, Vb and Ve, and the rotor position is then
calculated by a relationship of the type:
(90, coo) = f (ia, ib, lc, Va, Vb, Vc)
- The phase currents and the phase-neutral voltages at the output of
each of the N inverters, and the rotor position is then calculated by a
relationship of the type:
(Go, coo) = f (la, ib, lc, Va, Vb, Vc)
in which ia, ib, ic, et Va, Vb, Vc are defined by the equations (i)
reproduced below:
IN
iabc = ikabc , and Vabc = E Vkabc IN.
k=1 \ k=1
In the known solutions, a shared control member generates the phase
currents and the phase-neutral voltages for each of the N inverters. In
practice, the control member is the element which performs the regulation of
current and the generation of duty cycles. It takes the form, for example, of
a
circuit board with one or more components of the type microcontroller,
microprocessor or more simply, programmable logic circuit. The control
member has access to the phase current measurements ia, ib, ic, used for the
regulation of current, and to the phase-neutral voltages Va, Vb, Vc, which are
deduced from the duty cycles and from the input voltage of the inverter or
possibly from voltage sensors at the output of the inverter.
CA 02919086 2016-01-22
In the known solutions, the control member shared by the N inverters
therefore has all the information required for estimating the position.
However, this architecture has limits which the present invention seeks to
overcome. It actually involves a fixed assignment of the N inverters to the
5 electric machine. The inverter/inverters dedicated, for example, to an
electric
machine charged with starting up the turbine is only used when the aircraft is
on the ground before takeoff. In flight, the unused inverter represents an
unwanted mass and unwanted cost. Similarly, a failure of an inverter renders
an otherwise operational electric machine unusable. For these reasons, it is
desirable to have a more modular electrical architecture, which would allow
the assignment of one or more inverters to be modified between multiple
electric machines. Following the flight phase of the aircraft, or a particular
event such as the breakdown of an inverter, a new assignment of the
inverters could be considered.
A modular power bay controlling the power supply of a set of electric
machines distributed throughout the aircraft by means of a set of inverters is
envisaged. The implementation of such a modular bay encounters, in the
case of electric machines without position sensors, difficulties in estimating
the position of each one of the electric machines by means of phase currents
.. and phase-neutral voltages, to the extent that the architecture of the
inverters
charged with shaping the power supply signal of the machine is variable. On
the one hand, the position information must be available at the level of each
inverter, at high frequency for the phase current regulations; on the other
hand, the position estimator must be able to adapt simply to a reassignment
of the inverters.
To this end, the subject of the invention is a modular power bay
intended for an aircraft comprising a plurality of electric machines, a
plurality
of inverters, and a control member configured to assign to at least one
machine one or more inverters, according to the operational requirements of
each machine of the plurality of machines. The control member comprises,
for the at least one machine:
- at least one observer, able to measure phase currents and phase-
neutral voltages of an electrical power supply signal of said machine,
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- at least one estimator, able to determine a rotor position of said
machine, based on the measurements of at least one observer,
- means for communicating, to the inverter/each of the inverters
assigned to said machine, the following data:
o a control instruction for
the inverter/each of the inverters making
it possible to respond to the operational requirement of said
machine,
o measurements of at least one observer, or of the estimated
rotor position;
the inverter/each of the inverters being configured to generate an electrical
power supply signal for said machine according to the data transmitted.
Advantageously, the at least one estimator determines both the rotor
position and a rotor rotational speed of said machine, based on the
measurements of at least one observer, by means of a Kalman filter.
Advantageously, the control member comprises, for at least one
machine:
- a sole observer, measuring the phase currents and phase-neutral
voltages of the electrical input signal of said machine,
- a sole estimator, determining the rotor position based on the
measurements of the observer,
- the means for communicating, transmitting the estimated rotor position
to the inverter/each of the inverters assigned to said machine.
Advantageously, the control member comprises, for at least one
machine:
- an observer associated with the inverter/each of the inverters
assigned to said machine, measuring the phase currents and phase-
neutral voltages of the electrical output signal of the inverter with
which it is associated,
- a sole estimator, determining the rotor position based on the
measurements of the observer of the inverter/each of the inverters
assigned to said machine,
- the means for communicating, transmitting the estimated rotor position
to the inverter/each of the inverters assigned to said machine.
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Advantageously, the control member comprises, for at least one
machine:
- an observer associated with the inverter/each of the inverters
assigned to said machine, measuring the phase currents and phase-
neutral voltages of the electrical output signal of the inverter with
which it is associated,
- an estimator, determining the rotor position based on the
measurements of the observer of the inverter/each of the inverters
assigned to said machine,
- the means for communicating, transmitting on the one hand to the
estimator the measurements of the observer of the inverter/each of the
inverters assigned to said machine, and on the other hand to the
inverter/each of the inverters assigned to said machine the rotor
position estimated by the estimator.
Advantageously, the means for communicating transmit at high
frequency, the measurements of the observer of the inverter/each of the
inverters assigned to said machine and a synchronization signal, allowing a
synchronized estimation of rotor position.
Advantageously, the control member comprises, for at least one
machine:
- an observer associated with the inverter/each of the inverters
assigned to said machine, measuring the phase currents and phase-
neutral voltages of the electrical output signal of the inverter with
which it is associated,
- an estimator associated with the inverter/each of the inverters,
determining the rotor position based on the measurements of the
observer of the inverter with which it is associated,
- the means for communicating, transmitting to the inverter/each of the
inverters assigned to said machine, the rotor position of the
inverter/each of the inverters assigned to said machine.
the estimator of the inverter/each of the inverters determining a corrected
rotor position according to the rotor position of the inverter/each of the
inverters.
8
Advantageously, the means for communicating transmit at low frequency, to the
inverter/each of the inverters assigned to said machine, the rotor position of
the inverter/each of
the inverters assigned to said machine, and a synchronization signal to the
inverter/each of the
inverters, allowing the corrected rotor position to be determined in a
synchronized manner.
The invention also concerns an aircraft equipped with a modular power bay
having the
features previously described.
The invention also concerns a control method intended for an aircraft
comprising a plurality
of electric machines and a plurality of inverters, the method being
characterized in that it
comprises steps consisting in:
- assigning to at least one machine one or more inverters, according to the
operational
requirements of each machine of the plurality of machines,
- for the at least one machine:
o measuring phase currents and phase-neutral voltages of at least one
electrical power supply signal of said machine,
o determining
a rotor position of said machine, based on the measurements
of at least one electrical power supply signal of said machine,
o transmitting, to the inverter/each of the inverters assigned to said
machine,
the following information:
= a control instruction for the inverter/each of the inverters making it
possible to respond to the operational requirement of said machine,
= the measurements of at least one electrical power supply signal of said
machine, or the rotor position;
o controlling the inverter/each of the inverters assigned to said machine
according to the information transmitted.
According to another aspect of the invention, there is provided a modular
power bay for
an aircraft comprising a plurality of electric machines, inverters, and a
control member being
configured to be able to assign a plurality of said inverters to a first
machine of the plurality of
electric machines,
wherein the control member comprises:
proper observers to measure phase currents and phase-neutral voltages of
electrical power supply signals of said first machine, each of said proper
observers being
assigned to one of the inverters assigned to the first machine, and
Date Recue/Date Received 2021-10-04
8a
proper estimators to determine at least one estimated rotor position of said
first
machine based on the measurements of the proper observers, each proper
estimator
being assigned to one of the inverters assigned to the first machine,
means of communication:
for communicating a control instruction for each of the inverters assigned
to said first machine by the control member,
for communicating the estimated rotor position,
the means of communication being configured such that each of the inverters
being assigned to the first machine has each estimated rotor position of said
first machine
and each inverter assigned to the first machine being configured to use the
control
instruction and the estimated rotor position of said first machine to generate
an electrical
power supply signal for said first machine.
According to another aspect of the invention, there is provided a control
method for an
aircraft comprising a plurality of electric machines, the method comprising:
assigning a plurality of inverters to a first machine of the plurality of
electric machines,
for the first machine:
measuring phase currents and phase-neutral voltages of electrical power supply
signals of said first machine, by different proper observers, each proper
observer being
assigned to one of the plurality of inverters assigned to the first machine,
determining, by proper estimators, at least an estimated rotor position of
said first
machine, based on the measurements of phase currents and phase-neutral
voltages, based on
the measurements of the proper observers, each proper estimator being assigned
to one of the
inverters assigned to the first machine,
transmitting, to each of the inverters assigned to said first machine, the
following
information:
a control instruction for the assigned inverter, and
the estimated rotor position,
such that each of the proper estimators has each estimated rotor position of
said first
machine, each inverter assigned to the first machine using the control
instruction and the
estimated rotor position of said first machine to generate an electrical power
supply signal for said
first machine.
The invention will be better understood and other advantages will become
apparent upon
reading the detailed description of embodiments given by way of example in the
following figures.
Date Recue/Date Received 2021-10-04
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Figure 1, already introduced, illustrates the known principle of a
position estimator of an electric machine supplied with power by an inverter,
Figures 2a and 2b, already introduced, illustrate the known principle of
a position estimator of an electric machine supplied with power by multiple
inverters,
Figure 3 shows a first embodiment of a modular power bay according
to the invention,
Figure 4 shows a second embodiment of a modular power bay
according to the invention,
Figure 5 shows a third embodiment of a modular power bay according
to the invention,
Figure 6 illustrates the operation of a modular power bay according to
the third embodiment,
For the sake of clarity, the same elements will be given the same
references in the various figures.
Figure 3 shows a first embodiment of a modular power bay according
to the invention. Figure 3 shows a modular bay having an electric machine
and N inverters, to illustrate the principle of the invention in a simplified
manner. In effect, the invention concerns a modular bay for controlling the
power supply of a set of electric machines distributed throughout the aircraft
by means of a set of inverters; the modularity of the bay being obtained by
allowing a reassignment of the inverters during utilization of the aircraft,
in the
flight phase or on the ground. Similarly, certain machines can, under certain
conditions of use, be supplied with power by a sole inverter.
Thus, the modular power bay consists of a plurality of electric
machines 11, a plurality of inverters 10, and a control member 13 configured
to assign to each machine 11, on or more inverters 10, according to the
operational requirements of each machine 11.
The control member 13a comprises, for at least one machine:
- an observer 14a, measuring the phase currents ia, ib, ic and phase-
neutral voltages Va, Vb, Vc of the electrical input signal of said
machine,
- an estimator 15a, determining the rotor position 0 based on the
measurements ia, ib, ic, Va, Vb, Ve of the observer 14a,
, CA 02919086 2016-01-22
- means for communicating 16a, transmitting the estimated rotor
position 0 to the inverter/each of the inverters 10 assigned to said
machine 11.
In this first embodiment, the electric input signal of the machine in
5 question is implemented, by means of a device 12, commonly referred to as
parallel connection or coupling inductor, which ensures the bundling of the
electrical power signals of the sub-assembly of inverters assigned to this
machine. Advantageously, this device 12 is also modular and may be
adapted to a variable number of inverters.
10 The observer 14a comprises phase current ia, ib, ic sensors and
phase-
neutral voltage Va, Vb, Vc sensors at the input of the electric machine 11.
The estimator 15a determines both the rotor position 0 and a rotor
rotational speed w of the machine 11 in question, based on the
measurements i i IC,Va,v v f the observer 14a associated with said
.a, =b, . b, .c O.
machine, for example by means of a Kalman filter. As previously described,
the equation solved by the estimator is of the type:
(0, 0) = f (Ia, ib, ic, Va, Vb, Vc)
The control member 13a ensures the control of each electric machine 11
of the bay. The control member can be composed of a common electronic
device shared by all of the electric machines, each of the machines having
an estimator 14a. The estimators of each of the machines being able to be
integrated in the common electronic device or moved into proximity of each
of the machines and linked to the common device.
The means for communicating 16a must allow the rotor position 0 and the
rotor rotational speed CO to be communicated to each of the inverters eligible
to be assigned to the machine in question. Advantageously, the means for
communicating 16a link the control member to each of the inverters of the
bay, and transmit to each inverter the information on the position and speed
of the machine to which it is assigned.
Figure 4 shows a second embodiment of a modular power bay
according to the invention. In this second embodiment, one of the electric
machines of the modular bay is composed of multiple sub-machines, each
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supplied with power by an inverter. The control member 13b of the modular
bay thus comprises, for this machine:
- observers 14b associated with the inverter/each of the inverters 11
, .b, .c
assigned to this machine, measuring the phase currents i .a i and
phase-neutral voltages Va, Vb, Vc of the electrical output signal of the
inverter with which it is associated,
- an estimator 15b, determining the rotor position 0 and the rotor
rotational speed 0) based on the measurements of the observer 14b of
the inverter/each of the inverters 10 assigned to said machine,
- the means for communicating 16b, transmitting the rotor position 0
and the rotor rotational speed CO to the inverter/each of the inverters
10.
This second embodiment does not implement a parallel connection
device, the electric power signals of the inverters supplying power directly
to
the electric machine.
The observer 14b comprises phase current ia, ib, ic, sensors and
phase-neutral voltage Va, Vb, Vc sensors at the output of each of the
inverters
10 assigned to the machine.
The estimator 15b determines both the rotor position 0 and a rotor
rotational speed CO of the machine 11 in question, based on the
measurements ia, ib, IC, Va, Vb, Vc of the observer 14 associated with said
machine, for example by means of a Kalman filter. As previously described,
the equation solved by the estimator is then of the type:
(8, co) = f ib, ic, Va, Vb, Vc)
in which ia, ib, i G and Va, Vb, Vc are defined by the equations:
( N
iabc Eikabc, and Vabc = E Vkabc IN.
k=1 \,k=1
The control member 13b can be composed of a common electronic
device shared by all of the electric machines, each of the machines having
an estimator 14a being able to be integrated in the common electronic device
or moved into proximity of each of the inverters and linked to the common
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device. The means for communicating 16b link the control member 13b to
each of the inverters 10 of the bay, and transmit to each inverter the
information on the position and speed of the machine to which it is assigned.
Advantageously, the first and second embodiments can be combined
within one and the same bay. Certain electric machines can have a device 12
for the parallel connection of electrical power signals of a variable number
of
inverters, and other machines can comprise multiple sub-machines which
can be supplied with power by multiple inverters, the number of which can
also vary during use.
Figure 5 shows a third embodiment of a modular power bay according
to the invention. The modular bay comprises a plurality of machines and a
control member 13c capable of assigning one or more inverters to each of
the machines according to the operational requirements of the aircraft. A
machine of the bay shown in Figure 5 comprises a device 12 for the parallel
connection of the electrical power signals of N inverters.
In this embodiment, the control member 13c is not centralized in a
common electronic device, but moved into each of the inverters of the
electronic bay. Each inverter assigned to a machine thus comprises one
current and voltage observer 14c, and one estimator 15c.
In reality, this embodiment comprises two variants which can be
illustrated by the same Figure 5. In the first variant, the inverters are
linked by
a communication bus, i.e. the means for communicating 16c of the control
member 13c, so that they share the measurements of the estimators 15c of
each of the inverters. The estimator 15c of each of the inverters, or
advantageously of at least one of them, therefore determines the position
and speed of the machine using a relationship of the type:
N
(6), co) = f (ia,ib,ic,Va,Vb,Vc) with iabc =Zikabc , et Vabc = E Vkabc IN.
k=1 k=1
This solution requires a high-speed communication bus as the
estimator is generally executed at the calculating frequency of the current
loop, that generally being the frequency of the PWM duty cycles, or even
twice that frequency. The observers 14c therefore send their information on
CA 02919086 2016-01-22
13 =
the current and voltage via the means for communicating 16c, at this high
frequency.
Figure 6 illustrates the operation of a modular power bay according to
this first variant of the third embodiment. The estimators 15c of each of the
inverters 10 (the figure illustrates the case of two inverters) synchronize on
a
shared event of the type rising edge or falling edge of a synchronization
signal, or receipt of a specific frame over the communication bus. This allows
the totality of the current and voltage measurements of the observers 14c to
be synchronized, and therefore the error regarding the estimated position to
be limited.
In the first chronogram, at the top of the figure, a synchronization
frame is shown. The acquisition of measurements of the observers 14c of the
two inverters is carried out on a rising edge of this frame, illustrated by
the
second chronogram. Each of the observers then transmits its measurement
over the communication bus as illustrated by the third chronogram. The
measurements of each of the observers are then received by the estimator
15c of each of the inverters, which determines the position and speed of the
machine, as illustrated in the fourth chronogram.
As has been mentioned, it is advantageous, in this first variant, to limit
the calculation of position and speed to a sole inverter. The result of the
calculation is then transmitted to the other inverters by means of the
communication bus. This is the case selected in Figure 6, the information on
the position and speed of the machine, determined by the second inverter, is
used directly by this inverter for its control, and is also transmitted via
the
communication bus to the first inverter, as shown in the third chronogram.
Synchronization can be carried out via a digital signal such as a clock.
The frequency of this clock must be sufficient to allow the regular
readjustment of the internal clocks of the inverters Typically, a clock
frequency equal to the frequency of the duty cycles of the inverters will be
retained, for example 10 kHz. Synchronization between the inverters can
also be carried out by using a predefined frame of a communication bus
between the inverters.
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By way of illustration, for duty cycles of the two inverters with
frequency equal to 20 kHz, and data encoded with 16 bits, the usable
bandwidth over the communication bus is:
- for the transmission of the measurements: 3 currents + 3 voltages
4 96bits*20kHz=1.92Mbits/s
- for the transmission of the position and the speed: 1 position + 1 speed
4 32bit5*20kHz=0.64Mbits/s
i.e. a usable bandwidth of 2.56Mbits/s.
In the second variant, also illustrated by Figure 5, the estimators 15c
of each of the inverters 10 determine a position and a speed solely on the
basis of measurements of currents and voltages of the observer 14c
associated with this inverter, which considering that the other inverters
generate the same electrical power signals as it does, i.e. the same PWM
duty cycles. Typically, the estimator of the inverter denoted by 1 determines
a
rotor position 0/ and a rotor speed (.01 by means of the relationship:
(0/, on) = f (ia, ib, ic, Va, Vb, Vc),
r N
in which Vabc = IV1kabc I N =Vlabc , and iabc = N* ilabc .
k=1
Similarly, the estimator of the inverter denoted by k determines a rotor
position Ok and a rotor speed Wk by means of the relationship:
(0k, Wk) = f (ia,ib,ic,Va,Vb,Vc), With Vabc = Vkabc, and i .abc = N * ikabc
Each inverter k thus has information on the position Ok and speed cok,
which it transmits to the N other inverters using the means for
communicating. This information can be exchanged at low frequency, for
example the calculating frequency of the speed loop. A low-speed
communication bus can advantageously be retained in the case of this
second variant.
CA 02919086 2016-01-22
Next, the estimator of each of the inverters which have positions and
speeds determined by the totality of the N inverters, determine a corrected
rotor position and a corrected rotor speed, according to the information on
positions and speeds received from each of the inverters.
5 An envisaged solution is to determine, within each inverter, a
corrected position Ocorr and a corrected speed Wcorr as the average of the
positions and speeds of the totality of the inverters. Stated another way:
N (N 1
9 corr yo, I , and
W corr la) / N
Advantageously, the estimators of each of the inverters synchronize
on a shared event of the type rising edge or falling edge of a synchronization
signal, or receipt of a specific frame over the communication bus. The
information exchanged on position and speed corresponding advantageously
to one and the same perfectly defined instant for each of the inverters.
It should be recalled that Figures 3 to 5 only show a single electric
machine supplied with power by N inverters, but the invention concerns a
modular bay comprising a plurality of electric machines. To this end, the
control member is configured to assign to each machine one or more
inverters, according to the operational requirements of each machine of the
plurality of machines. The simplified representation in Figures 3 to 5 allows
a
difficulty overcome by the present invention to be illustrated, that of the
management of the estimation of position of each of the electric machines
without position sensors, and thus by means of the phase currents and
phase-neutral voltages, in order to allow a modular architecture of the power-
supply inverters of the electric machines.
The various embodiments and variants which have been described
present distinct advantages and disadvantages. For example, the first
embodiment is relatively simple to implement but has the disadvantage of
requiring the addition of dedicated electronics and a certain number of
supplementary voltage and current sensors. The first variant of the third
embodiment advantageously allows greater precision in the estimation of
position while limiting the additional cost in terms of sensors, as it makes
use
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of information on currents and voltage available at the level of the inverter.
But in order to do this, this architecture requires a high-speed communication
bus to be implemented between each of the inverters or between some of the
inverter sub-assemblies of the bay.
Nevertheless, all of the solutions proposed by the present invention
have in common that they provide a solution to the problem of the modularity
of the assignment of the inverters for controlling a set of electric machines
of
an aircraft. The modular bays according to the invention thus have in
common a plurality of electric machines 11, a plurality of inverters 10, and a
control member, 13a, or 13b or 13c, configured to assign to at least one
machine 11 one or more inverters 10, according to the operational
requirements of each machine 11 of the plurality of machines 11,
characterized in that the control member comprises, for the at least one
machine 11:
- at least one observer, able to measure phase currents i and
.a, .b, .c
phase-neutral voltages Va, Vb, Vc of an electrical power supply signal
of said machine 11,
- at least one estimator, able to determine a rotor position 0 of said
machine 11, based on the measurements of at least one observer,
- means for communicating, to the inverter/each of the inverters 10
assigned to said machine 11, the following data:
o a control instruction for the inverter/each of the inverters 10
making it possible to respond to the operational requirement of
said machine 11,
o measurements of at least one observer, or of the estimated
rotor position a
the inverter/each of the inverters 10 being configured to generate an
electrical power supply signal for said machine 11 according to the data
transmitted.
The invention also concerns a control method intended for an aircraft
comprising a plurality of electric machines 11 and a plurality of inverters
10,
the method being characterized in that it comprises steps consisting in:
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- assigning to at least one machine 11 one or more inverters 10,
according to the operational requirements of each machine 11 of the
plurality of machines 11,
- for the at least one machine 11:
o measuring phase currents a, .b, c i i and phase-neutral voltages
. .
Va, Vb, Vc of at least one electrical power supply signal of said
machine 11,
O determining a rotor position 0 of said machine, based on the
measurements ia, ib, ic, Va, Vb, Vc of at least one electrical
power supply signal of said machine 11,
o transmitting, to the inverter/each of the inverters 10 assigned to
said machine 11, the following information:
= a control instruction for the inverter/each of the inverters
10 making it possible to respond to the operational
requirement of said machine 11,
= the measurements ia, ib, ic, Va, Vb, Vc of at least one
electrical power supply signal of said machine 11, or the
rotor position 0,
o controlling the inverter/each of the inverters 10 assigned to said
machine 11 according to the information transmitted.
