Method of controlling an electrical machine by means of a controller with a proportional regulator and a proportional-integral regulator

Abstract

The present invention relates to a method and a system for controlling an electrical machine (MEL) driven by an inverter (OND), in which the control of the inverter (OND) is determined. The invention implements a step of determining current setpoints idsp, iqsp from torque setpoints or other variables. Then, the invention implements a step of determining voltage setpoints, by a controller (PI-P) which comprises a proportional regulator in parallel with a proportional integral regulator. Figure 2 to be published

Description

Title of the invention: Method for controlling an electrical machine by means of a controller with a proportional regulator and a proportional-integral regulator Technical field

[0001] The present invention relates to a method for controlling a rotating electrical machine, preferably a synchronous electrical machine, for example of the synchro-reluctant or permanent magnet synchronous type or a salient pole machine.

[0002] The invention also relates to a control system implementing such a method.

[0003] It is known to use rotating electrical machines such as permanent magnet synchronous electrical machines or synchro-reluctant machines, in particular synchro-reluctant machines assisted by permanent magnets. Such electrical machines are, for example, used in the field of propulsion, for example for the generation of engine torques on board a vehicle such as a motor vehicle.

[0004] Document FR 3 051 296 A1 describes, for example, a synchro-reluctant machine assisted by permanent magnets.

[0005] A method for controlling such an electrical machine generally comprises the calculation of so-called "direct" and "quadrature" (also called "quadratic") currents and voltages, which are currents and voltages expressed in a rotating frame linked to the rotor, and the implementation of one or more servocontrols, in order to determine the voltages to be applied to each phase of the rotating machine. In the case of the implementation of two servocontrols, one may relate to the so-called "direct" quantities, and the other may relate to the so-called "quadrature" quantities,

[0006] Therefore, determining the reference (also called setpoints), direct and quadrature components of the stator current is a crucial step at this level, in order to guarantee an optimal level of performance of the electrical machine. The complexity of determining the reference current depends on the nature of the machine used:

[0007] - For a smooth-pole, magnetically unsaturated synchronous machine, the com direct and quadratic current variables can be obtained in a linear and direct manner from the required torque, and

[0008] - For other machines, such as saturated magnetic synchro-reluctant machines Tically, obtaining the reference components of the stator current calls upon more sophisticated and complex methods, moreover, these machines have a strong decoupling between the direct axis and the quadratic axis, particularly in the presence of physical constraints such as the limitation of the battery voltage and current, the thermal state of the machine. These constraints and those of real time, such as the discontinuity of the signals, the variation of the parameters, the modeling errors and the measurements can be at the origin of deterioration of the performances and the instability of the control of the stator current. Prior art

[0009] Many methods have been developed for the control of electrical machines.

[0010] For example, patent applications FR3089368 (US 2022 / 006013) and FR3131992 describe methods for controlling an electrical machine to manage the defluxing of electrical machines. Although satisfactory for the management of defluxing, these methods do not allow stabilized decoupling between the direct axis and the quadrature axis of the control in the presence of significant coupling.

[0011] Patent applications JP2003052200 and US20220329186 describe approaches implementing a PI (proportional integral) controller of the current setpoints without decoupling. Patent applications CN102594254, US20220368255 describe in particular approaches implementing a PI (proportional integral) controller of the current setpoints with direct decoupling. Patent application CN111211720 describes an approach implementing a PI controller of the current setpoints with offset compensation on the rotor angle and integration of the electromotive force. These methods do not allow stabilized decoupling between the direct axis and the quadrature axis of the control in the presence of significant coupling. Summary of the invention

[0012] The present invention aims to control an electrical machine in real time with control stability, in an efficient and robust manner. For this purpose, the present invention relates to a method and a system for controlling an electrical machine driven by an inverter, in which the control of the inverter is determined. The invention implements a step of determining current setpoints from torque setpoints or other variables. Then, the invention implements a step of determining voltage setpoints by a controller which comprises a proportional regulator in parallel with a proportional integral regulator. The use of such a controller with a parallel regulator and a proportional integral regulator allows stabilized decoupling between the direct axis and the quadratic axis, in particular for an electrical machine with significant coupling. Thus, the control of the electrical machine is stable, efficient and robust.

[0013] The invention relates to a method for controlling an electrical machine comprising several phases and controlled by an inverter provided with a switching arm per phase of said electrical machine. The following steps are implemented: a. A torque setpoint of said electric machine and / or a setpoint or measurement of at least one operating variable (VAF) of said electric machine is acquired; b. The current in said phases of said electrical machine is measured; c. Current setpoints for said electrical machine are determined by function of said torque setpoint and / or said setpoint or measurement of said at least one operating variable; d. Voltage setpoints of said electrical machine are determined from said current setpoints of said electrical machine and said current measured in said phases of said electrical machine, by means of a controller which comprises a proportional regulator in parallel with a proportional integral regulator; e. A switching control signal for said switching arms of said inverter is determined by means of said voltage setpoints; and f. Said switching arms of said inverter are controlled by means of said switching control signal.

[0014] According to one embodiment, said controller implements the following calculation: h* ; V jt. F / ;* ; Ut with 'cs instructions of ^dq p^dq^-dq ^dqmj'^-i,dqj\^dq Idqjnplt voltage in the Park reference frame, KF') the coefficient of said proportional regulator as a function of the electrical rotation speed œ of the rotor of the electric machine, idqjn the current measured in the phases of the electrical machine expressed in the reference frame Park, Kpjq the proportional coefficient of said proportional integral regulator in the Park's landmark, Kg the current instructions in the Park frame, K^iq the coefficient integral of said proportional integral regulator in the Park frame.

[0015] According to one embodiment, a switching duty cycle of the BACKGROUND arms is determined by including said counter electromotive force using the equation: es = [ 0 - çw] T with 'c "ux of the permanent magnets of said electric machine.

[0016] Advantageously, said proportional coefficient K(to) is determined by means of the following formula: w) = - F) with Lq Rs and B- q 1 and F a diagonal matrix containing poles to be placed to stabilize the transition matrix (AÇcè) - BK\ the stator resistance of the electric machine, Lq the quadrature inductance of the electric machine, Ld the direct inductance of the electric machine.

[0017] According to an implementation, said current setpoints idsP are determined and iqsP of said electric machine by means of a control model which links said torque setpoint, and / or said at least one operating variable, and said current setpoints i / p and iqsP of said electric machine, preferably said control model being a mapping linking said torque setpoint and / or said operating variables, and said current setpoints idsP and iqsP

[0018] According to one aspect, said method comprises a saturation of said determined voltage setpoint 0 * , Vq ). ' d

[0019] Advantageously, said saturation of the voltage setpoint implements a low-pass filter correcting said current setpoints (idsP, iqsP) in the event of exceeding a maximum voltage amplitude.

[0020] Preferably, said maximum voltage amplitude is determined by measuring the voltage of a DC voltage source supplying said electrical machine weighted by a Pulse Width Modulation index.

[0021] According to one embodiment option, said switching control signal is determined by means of vector control.

[0022] Furthermore, the invention relates to a system for controlling an electrical machine comprising an inverter provided with switching arms, a computer and a memory configured to implement the steps of the control method according to one of the preceding characteristics for controlling said inverter, preferably said electrical machine being a synchro-reluctant machine assisted by permanent magnets or a salient pole electrical machine.

[0023] Other characteristics and advantages of the method and system according to the invention will appear on reading the following description of non-limiting examples of embodiments, with reference to the figures appended and described below. List of figures

[0024] [Fig.l]

[0025] [Fig.l] illustrates the control system according to one embodiment of the invention.

[0026] [Fig.2]

[0027] [Fig.2] illustrates the steps of the method according to a first embodiment of the invention.

[0028] [Fig.3]

[0029] [Fig.3] illustrates the controller according to one embodiment of the invention.

[0030] [Fig.4]

[0031] [Fig.4] illustrates the steps of the method according to a second embodiment of the invention.

[0032] [Fig.5]

[0033] [Fig.5] illustrates the steps of the method according to a third embodiment of the invention.

[0034] [Fig.6]

[0035] [Fig.6] illustrates, for a comparative example, curves of torque, direct current and quadratic current as a function of time, the curves corresponding to a reference, to three embodiments according to the prior art, and to an embodiment of the invention. Description of the embodiments

[0036] In [Fig.l] is shown, schematically and in a non-limiting manner, an installation comprising a rotating electrical machine MEL associated, for its control, with a COM control system according to the invention (the COM control system implementing the control method according to the invention). The installation also comprises a DC source of electrical energy, such as a direct voltage bus.

[0037] The rotating electrical machine MEL is a rotating machine with several phases, preferably three phases (alternatively the electrical machine may comprise a number of phases that is a multiple of three, for example six, nine or twelve, or else four or five phases). Advantageously, the rotating electrical machine MEL may be a synchronous electrical machine. Preferably, the synchronous electrical machine MEL may be a permanent magnet or synchro-reluctant synchronous electrical machine, in particular a three-phase synchro-reluctant rotating machine assisted by permanent magnets. Indeed, such electrical machines have significant decoupling capacities.

[0038] For the illustrated example (non-limiting), the synchronous electric machine MEL has three inputs. Each input corresponds to a phase of a stator (not shown) of the rotating electric machine MEL.

[0039] The control system COM is intended to control, over time, the power supply of the rotating machine MEL as a function of target values ​​and / or measured values ​​of predetermined quantities. These target values ​​and / or measured values ​​are called in the remainder of the description operating variables of the electric machine. For the method and the system according to the invention, the control system COM takes into account a torque setpoint Cem* (which can conventionally come from a request from the user of the electric machine, alternatively this torque setpoint can be calculated by speed regulation), and / or at least one other operating variable VAF which can be a measurement or a setpoint. An operating variable of the electric machine is a quantity which characterizes the operation of the electric machine, it can be in particular an electrical variable, such as the voltage, the current, or the power of the electric machine, a mechanical variable such as the position, the speed or the acceleration of the rotor of the electric machine, etc.The operating variables can for example be the electrical rotation speed coe of the rotor (not shown) of the electric machine (alternatively this variable can also be the norm of the magnetic flux in the phases), the voltage amplitude of the electric machine, the current amplitude of the electric machine, a temperature of the electric machine, the magnetic flux due to the magnets, etc. It is recalled that the electrical rotation speed coe of the rotor corresponds to the multiplication of the mechanical rotation speed com of the rotor by the number of pairs of poles of the synchronous electric machine MEL. In other words, we can write: coe=P-tt>m with p the number of pairs of poles of the synchronous electric machine MEL.

[0040] The COM control system comprises an OND inverter and a CAL computer. The COM control system may, if necessary, comprise a CAP sensor for the angular position and / or angular rotation speed of the rotor of the MEL electrical machine. Such a sensor makes it possible to determine the angular rotation speed com of the electrical machine either directly (in the case of a speed sensor) or by derivation (in the case of the position sensor). In addition, the COM control system may comprise means for measuring the currents (not shown) in the phases of the electrical machine, for example current sensors.

[0041] The inverter OND is configured to route electrical energy between the DC source and the synchronous electrical machine MEL. More specifically, the inverter OND is configured to route electrical energy between the DC source and each phase of the stator of the synchronous electrical machine MEL. The DC source (for example a battery) provides a direct bus voltage, denoted VDC.

[0042] The OND inverter comprises a first input connected to the DC source, and three outputs, each connected to a corresponding phase of the stator of the synchronous electrical machine MEL. The OND inverter further comprises a second input electrically connected to an output of the CAL computer, so that the OND inverter is configured to route electrical energy between the DC source and the synchronous electrical machine MEL according to a switching control signal. applied by the CAL calculator to the second input of the OND inverter.

[0043] Preferably, the switching control signal may be such that the inverter OND routes electrical energy from the DC source to the synchronous electrical machine MEL so that the synchronous electrical machine MEL has an operation commonly called a "motor" and / or an operation commonly called a "generator". Conventionally, the inverter OND comprises several switching arms (not shown), preferably at least one switching arm for each phase of the electrical machine, to transform the DC signal from the DC source into an AC signal for the phases of the electrical machine MEL. Each switching arm comprises at least one controlled switch. Conventionally, each switch of the switching arms can be controlled by means of a pulse width modulation known by the acronym MLI (or PWM from the English Pulse Width Modulation).

[0044] Furthermore, the optional CAP angular position or angular rotational speed sensor can be configured to apply the angular position (respectively angular rotational speed) signal to a corresponding input of the CAL computer.

[0045] In the present application, the index d indicates the “direct” value in the Park frame, the index q indicates the “quadratic” value in the Park frame, and the index dq indicates a vector of the “direct” and “quadratic” values. For example, the voltage vdq designates the voltages (vd, vq).

[0046] The method for controlling a rotating electrical machine according to the invention comprises the following steps in real time: - Acquisition (reception) of the torque setpoint of the electric machine and / or acquisition of a setpoint or a measurement of one or a plurality of operating variables of the electric machine, - Measurement of the current in the phases of the electrical machine, using a current sensor, - Determination of the current setpoints of the electric machine, as a function of the torque setpoint and / or the setpoint or measurement of one or more operating variables, - Determination of voltage setpoints for the electrical machine, as a function of the current setpoints and the measured current, by means of a controller which includes a proportional integral regulator (noted PI regulator) in parallel with a proportional regulator (noted P regulator), - Determination of an inverter switching control signal using voltage setpoints, and - Control of the inverter by means of the switching control signal.

[0047] In the remainder of the description and in the claims, the term "current setpoints" designates either the "direct" and "quadrature" current setpoints, or the current standard and the defluxing angle, or any other equivalent representation of the currents.

[0048] As a reminder, a proportional regulator P makes it possible to generate an output command proportionally to an input difference. In this case, the output voltage of the proportional regulator is proportional to the difference between the current setpoint and the measured current.

[0049] As a reminder, a PI proportional-integral regulator makes it possible to generate an output command, which includes a term proportional to an input deviation (in this case the difference between the current setpoint and the measured current) and a term integrating the deviation. The integral term makes it possible to compensate for the static error, and provides a more stable system in steady state.

[0050] Thus, the control method determines voltage setpoints by means of a specific controller, which ensures stabilized decoupling between the direct axis and the quadratic axis, in particular for an electrical machine with significant coupling. Indeed, thanks to this controller comprising a PI regulator and a P regulator in parallel, an additional degree of freedom, compared to a PI controller alone, is added to be able to act on the transients without necessarily causing an overshoot compared to the desired current references. Thanks to this structure, the control system and method according to the invention can ensure transients on the torque having relatively high dynamics in all operating zones of the electrical machine by reducing, by state feedback, resonances or oscillating transients. Thus, the control of the electrical machine is stable, efficient and robust.

[0051] Figure 2 illustrates, schematically and in a non-limiting manner, the system and the control method according to a first embodiment of the invention. The elements identical to those of Figure 1 are not detailed again. In a first step, a torque setpoint Cem* and / or a setpoint or a measurement of an operating variable VAF are acquired. Currents ia, ib, ic are measured in the phases of the electrical machine MEL, which are converted into the direct axis idm and the quadratic axis iqm by the Clark transform from three-phase to two-phase and by the Park rotation with the estimated or measured rotor angle. Current setpoints Q and / * are determined by means of an MCO control model from the torque setpoint Cem* and / or a setpoint or a measurement of an operating variable VAF. Then, voltage setpoints are determined from a PLP controller, from the current setpoints Q and i* and the current measurements idm and iqm. Then,

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] determines a switching control signal SVM of the OND inverter using the voltage setpoints. The MCO, PLP, SVM steps are implemented using the CAL calculator of the COM control system of the MEL electrical machine. Conventionally, the controller that determines the voltage setpoints only includes a PI regulator, which can be defined with the following equation: ^dq pjdc^dq ' d" K i,dq\( / dq “ ^dqjn^^ ' ^^dq With vd the voltage setpoint expressed in the Park frame (comprising the direct voltage setpoint and the quadratic voltage setpoint Vq), idc the current setpoint expressed in the Park frame (comprising the direct current setpoint id and the quadratic current setpoint fp, the measured current expressed in the Park frame (comprising the direct measured current id^n (also noted idm) and the quadratic measured current iq / n (also noted iqm)), &dq The vector of the coupling components expressed in the Park frame (comprising the direct induced flux &d and the quadratic induced flux 0q\ the proportional coefficient of the PI regulator expressed in the Park frame (comprising the direct proportional coefficient AT and the quadratic proportional coefficient Kp#), the integral coefficient of the PI regulator expressed in the Park frame (comprising the direct integral coefficient Kid and the quadratic integral coefficient According to one embodiment of the invention, the controller comprising a PI regulator in parallel with a P regulator can be written: ^dq — 5" ^pd^dq “ hlqm j "hi,dq^(îdq ” îdqjnfât With vd the voltage setpoint expressed in the Park frame (comprising the direct voltage setpoint vd and the quadratic voltage setpoint v^, Q the current setpoint expressed in the Park frame (comprising the direct current setpoint id and the quadratic current setpoint j* ), idqjn the measured current expressed in the Park frame (comprising the direct measured current k / ,™ (also noted idm) and the quadratic measured current iqj» (also noted iqm)), the proportional coefficient of the PI regulator expressed in the Park frame (comprising the direct proportional coefficient Kpd and the quadratic proportional coefficient le co efficient integral of the PI regulator expressed in the Park frame (including the direct integral coefficient and the quadratic integral coefficient K(w) the coefficient of said proportional regulator as a function of the electrical rotation speed œ of the rotor of the electric machine expressed in the Park frame (including the direct proportional coefficient Kd and the quadratic proportional coefficient Kq). In

[0058] Based on the current error (difference between reference and measurement), the PI regulator is applied in closed loop to produce a first reference voltage. This PI regulator stabilizes the decoupled part of the machine and it is based on its decoupled model. Based on the measured stator current, the proportional regulator of the coupling components between the d-axis and the q-axis is applied in closed loop to produce a second reference voltage. This controller stabilizes the coupled part of the machine and it is based on its coupled model. Figure 3 illustrates, schematically and in a non-limiting manner, a controller according to an embodiment of the invention. The upper part of the figure concerns the direct axis of the Park frame, and the lower part of the figure concerns the quadratic axis of the Park frame. The PLP controller determines the voltage setpoints and Vq from the current setpoints Q and and the measured current idm and iqm. In this figure, the PI regulator of the direct axis is represented by the block + - ct 'c regulator P of the axis direct is represented by the Kd block. In this figure, the PI regulator of the qua axis dratic is represented by the block kPq + and the regulator P of the quadratic axis is represented by the Kq block.

[0059] According to one embodiment, the counter electromotive force can be determined by means of the equation: e = [0 - T with V the flux of the permanent magnets of said electric machine and 07 the electrical rotation speed of the rotor of the machine electric.

[0060] According to an implementation of the invention, the proportional coefficient K(œ) can be determined by means of the following formula: 7^0 = - F) with 1 q 1 and F a diagonal matrix containing poles to be placed to define and stabilize the transition matrix (A(o;) - BK\ Rs the stator resistance of the electric machine, Lq the quadrature inductance of the electric machine, Ld the direct inductance of the electric machine.

[0061] According to one aspect of the invention, the current setpoints of the electric machine can be determined by means of a control model which links the torque setpoint, and / or the at least one operating variable, and the current and electric machine setpoints for optimal efficiency in all operating zones of the machine. According to one embodiment of the invention, the control model control can be a numerical model (e.g. resulting from numerical simulations of the electrical machine), an analytical model or a mapping that links the torque setpoint, the operating variables including the corrected operating variable and the current setpoints. Preferably, the control model may be a map linking the torque setpoint, and / or said operating variables and said current setpoints. Preferably, the control method may implement two maps, one for the direct current setpoint, and one for the quadrature current setpoint (or respectively one for the current standard and one for the defluxing angle). Advantageously, such maps may be data from the manufacturer of the electrical machine, or may be obtained by simulation or experimentally. For example, the maps used may be maps which minimize iron losses for the electrical machine in addition to Joule losses.

[0062] Advantageously, the voltage setpoints can be converted into a switching control signal for the inverter by means of a space vector control noted SVM (from the English “Space vector modulation”), or any similar method.

[0063] According to an implementation of the invention, the method may comprise a step of saturating the voltage setpoints determined by the controller, to ensure closed-loop current control in the event of voltage limitation (in other words to prevent the determined voltage setpoints from exceeding the DC voltage of the voltage source).

[0064] [Fig. 4] illustrates, schematically and in a non-limiting manner, the system and the method according to a second embodiment. The elements identical to [Fig. 2] are not detailed again. The PLP controller determines so-called optimal voltage setpoints Vd°pt and Vq°pt, which are, where appropriate, saturated S AT by the maximum available voltage, linked to the voltage of the direct voltage source DC. At the output of this saturation step, the voltage setpoints Vd* and Vq* are determined and used to determine a switching control signal for the inverter. The SAT step is implemented by means of the CAL computer of the COM control system of the MEL electrical machine.

[0065] According to a first embodiment of this implementation, the saturation of the voltage setpoint can implement a low-pass filter correcting said current setpoints, by correcting the current defluxing angle (as a reminder, this defluxing angle ^defiux. is linked to the direct and quadratic current by the relation; ® = tan"1— ct Which varies according to the maximum flow level and the rotation speed ^deflux id of the machine) in the event of exceeding a maximum voltage amplitude. For example, three low-pass filters can be used to dampen any fairly rapid transients in the angle and amplitude of the current setpoint. A first low-pass filter can be provided in the voltage measurement feedback loop of the voltage source, a second low-pass filter can be provided for the direct current setpoint and a third low-pass filter can be provided for the quadratic current setpoint. In addition, the closed-loop zeros of the current controllers can be eliminated by carefully choosing the dynamics of the two low-pass filters used on the direct and quadratic current setpoints.

[0066] Advantageously, the maximum voltage amplitude can be obtained by measuring the voltage of the DC voltage source weighted by a pulse width modulation index PWM. Indeed, the following equation can be written: Usmax = mVDC with Usmax the amplitude of the maximum voltage between the phases of the electrical machine, VDC the bus voltage (voltage of the DC voltage source), and m the modulation index of the pulse width modulation (PWM) used.

[0067] Advantageously, a closed-loop control module for the voltage amplitude can be introduced to compensate for any possible excess of the overall voltage obtained by the PI regulator and the P regulator compared to the maximum voltage available from the power source.

[0068] Figure 5 illustrates, schematically and in a non-limiting manner, a method and a system according to a third embodiment implementing the different variants listed above. The elements identical to Figure 4 are not detailed again. For this embodiment, a limitation step LIM is provided, to control the voltage limitation, on a loop for measuring the voltage of the DC voltage source. This limitation step determines a limitation of the current setpoint angle as a function of the maximum voltage amplitude (which can be weighted by a pulse width modulation index). This limitation of the current setpoint angle is then filtered in a low-pass filter FIL.This filtered limitation of the current angle is used in a COR step of the current setpoints id* and iq* to determine corrected current setpoints idc and iqc, which then take into account the limitation of the voltage amplitude. During this COR step, an angle of the current setpoints id* and iq* is determined which is compared with the filtered limitation of the current angle gf. A low-pass filter step FIL, with a low-pass filter per axis (direct and quadratic) is used to determine the filtered current setpoints idfet iqf at the input of the PLP controller. At the output of the PLP controller, a closed-loop SAT control module of the voltage amplitude is introduced to compensate for any excess of the overall voltage obtained by the PI regulator and the P regulator compared to the maximum voltage available from the power source (which can be weighted by a pulse width modulation index).The LIM, FIL, COR and SAT steps are implemented by means of the CAL calculator of the COM control system of the MEL electric machine.

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[0085] The control system according to the invention comprises an inverter, a means for measuring the current in the phases of the electrical machine (for example current sensors), possibly a position and / or speed sensor of the rotor of the electrical machine, and a computer and a memory configured to implement the steps of the control method according to any one of the variants or combinations of variants described previously. According to one embodiment of the invention, the rotating electrical machine may be a synchronous electrical machine, preferably a permanent magnet-assisted synchronous-reluctant electrical machine or a salient pole electrical machine. Indeed, the method and the system according to the invention are particularly suitable for this type of electrical machine, in particular because the invention makes it possible to take into account the constraints and the operation of all types of machines. Comparative example The characteristics and advantages of the method according to the invention will appear more clearly on reading the application example below. For this comparative example, we aim to control a permanent magnet synchronous-reluctant electric machine comprising 4 pairs of poles, having a stator resistance of 8.2 mOhm, and a permanent magnet flux of 0.024 Wb. The electric machine is powered by a 350 V battery. The maximum current in the electric machine is 640 A, and the maximum rotational speed of the electric machine is 14000 rpm. For this electric machine, we apply a dynamic model of the form: (di^ Rs . Lg . f . J_v X / , dt ~ ~ Lq Md Lq^~ Lq ij, iq: direct and quadrature components of the stator current; direct and quadrature components of the stator voltage: magnet flux a-: electrical pulse Rs: stator resistance Ld ; inductance in the d axis Lq ; inductance in the q axis Furthermore, we apply a torque model of the form: With Cem the torque of the electric machine, P the number of pole pairs of the electric machine.

[0086] A simulation of this electrical machine and its control method is implemented, with a Runge-Kutta method of order 4 and an Euler approximation of order 1 for the integrators of the controllers. The components of the reference currents were obtained by 2D data tables to remain within a control limitation with the strategies MTPA (from the English "maximum torque per ampere", which can be translated as maximum torque per ampere) and MTPV (from the English "maximum torque per volt" which can be translated as maximum torque per volt).

[0087] For this example, we compare control methods with controllers formed respectively by: - A PI regulator only and without switching, according to an embodiment of the prior art, noted AA3, - A PI regulator only with measurement-based cutting, according to a prior art embodiment, noted AA2, - A PI-only regulator with reference-based switching, according to a prior art embodiment, noted AAI, - A PI regulator in parallel with a P regulator in accordance with an embodiment of the invention, denoted INV.

[0088] For these control methods, a torque setpoint is applied in the form of a torque step for a rotor rotation speed of 14000 rpm. [Fig.6] illustrates curves of the torque Ce in Nm, and direct current id of the phases of the electric machine in A and quadratic current iq of the phases of the electric machine in A as a function of time t in s. The torque step occurs at 0.005 s. In [Fig.6] the reference value REF is shown as well as the curves obtained for the different control methods INV, AAI, AA2, and AA3. It should be noted that the control method of the invention makes it possible to obtain a torque and currents close to the reference, with rapid dynamics, and without exceeding the reference, unlike the methods according to the prior art which generate torque and current overshoots. Thus, the method according to the invention allows rapid stabilization (without overshoot) of the torque setpoint.

Claims

Claims

1. Method for controlling an electrical machine comprising several phases and driven by an inverter (OND) provided with a switching arm per phase of said electrical machine (MEL), characterized in that the following steps are implemented: a. A torque setpoint (Cem*) of said electric machine and / or a setpoint or measurement of at least one operating variable (VAF) of said electric machine is acquired; b. The current in said phases of said electrical machine is measured; c. Current setpoints (idsP, iqsp) of said electrical machine are determined as a function of said torque setpoint and / or said setpoint or measurement of said at least one operating variable (VAF); d. Voltage instructions / ) of said ' d electric machine from said current setpoints of said electric machine and said current measured in said phases of said electric machine, by means of a controller which comprises a proportional regulator (P) in parallel with a proportional integral regulator (PI); e. A control signal (SVM) for switching said switching arms of said inverter is determined by means of said voltage setpoints; and f. Said switching arms of said inverter are controlled by means of said switching control signal.

2. The method of claim 1, wherein said controller implements the following calculation: ^dq — "b pjdi^dq “ ^dqjn^ "b ^i,dq^(jdq ” îdqjnfât voltage instructions in the Park frame, K(üj) the coefficient of said proportional regulator as a function of the electrical rotation speed œ of the rotor of the electric machine, the current measured in the phases of the electric machine expressed in the Park frame, Kp^q the proportional coefficient of said proportional integral regulator in the

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6.

7.

8. Park's landmark, R / q the current instructions in the Park reference frame, the integral coefficient of said proportional integral regulator in the Park frame. Method according to claim 2, in which a switching duty cycle of the arms of the inverter (OND) is determined by including said counter electromotive force by means of the equation: e ! = [ 0 - 1 with 'c ^ ux of the permanent magnets of said electric machine. Method according to one of claims 2 or 3, in which said proportional coefficient K(œ) is determined by means of the following formula: K(m) = - F) with / \ r rs i —- — — 0 and F a matrix Ri Ri JA (V — and B~ Ri . . R n _L _ ■■■■■■■■■■■ / 11 _ ,■■■■■■■■■■ Lti ' Lq , Lq. diagonal containing poles to be placed to stabilize the transition matrix (A(o;) - BK\ R, the stator resistance of the electric machine, Lq the quadrature inductance of the electric machine, Ld the direct inductance of the electric machine. Method according to one of the preceding claims, in which said current setpoints i / p and iqsP of said electrical machine (MEL) are determined by means of a control model (MCO) which links said torque setpoint (Cem*), and / or said at least one operating variable (VAF), and said current setpoints idsP and iqsP of said electrical machine, preferably said control model being a mapping linking said torque setpoint (Cem*) and / or said operating variables (VAF), and said current setpoints idsP and iqsP Method according to one of the preceding claims, wherein said method comprises saturating said voltage setpoint ¢ / , ) determined. Method according to claim 6, wherein said saturation of the voltage setpoint implements a low-pass filter (FIL) correcting said current setpoints (idsP, iqsP) in the event of exceeding a maximum voltage amplitude. A method according to claim 7, wherein said maximum voltage amplitude is determined by measuring the voltage of a source of direct voltage supplying said electrical machine (MEL) weighted by a Pulse Width Modulation index.

9. Method according to one of the preceding claims, in which said switching control signal is determined by means of vector control.

10. System for controlling an electrical machine (MEL) comprising an inverter (OND) provided with switching arms, a computer and a memory configured to implement the steps of the control method according to one of the preceding claims for controlling said inverter (OND), preferably said electrical machine (MEL) being a synchronous-reluctant machine assisted by permanent magnets or a salient pole electrical machine.

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