Intelligent converter for synchronous motor

Abstract

Intelligent converter for synchronous motor One aspect of the invention relates to an intelligent converter C for synchronous motor comprising transistors t for converting direct current into alternating current on each phase line P1, P2, P3, a current sensor IP1, IP2, IP3 per phase line P1, P2, P3 and an intelligent control unit U1 for controlling each transistor t to form, on each line, an overall alternating voltage signal comprising a superposition of an alternating power voltage signal with a measurement signal having a frequency at least 20 times greater than the first frequency of the power signal.The intelligent control unit U1 demodulates the signals Si1, Si2, Si3 from the current sensors Ip1, Ip2, Ip3 to identify two possible rotor angular positions and simultaneously extracts the sign of a second-order harmonic of the current from each measurement signal Si1, Si2, Si3 to estimate the rotor angular position among the two identified possible positions. Figure to be published with the abbreviation: Figure 1.

Description

Title of the invention: Intelligent converter for synchronous motor TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of converters for synchronous motors with permanent magnet rotors.

[0002] The present invention relates to an intelligent converter for a synchronous motor and in particular to a rectifier inverter converter for evaluating the position of the rotor without a sensor, as well as to a system comprising the converter and the synchronous motor. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] There are different types of synchronous motor, including the synchronous motor having a permanent magnet rotor. It is known to use an inverter rectifier converter to convert a direct voltage into an alternating voltage to supply phases of the synchronous motor in order to create a rotating stator field Hs. During the operation of this motor, an alternating voltage is therefore applied to the windings of a stator, and an alternating current generated from the applied voltage flows through the windings. The particularity of the synchronous motor is to have a rotation speed that is a function of the supply frequency of the phases and / or the amplitude of the rotating stator field Hs. It is thus known to use an angular measurement sensor of the rotor (encoder or resolver) to detect the exact position of the rotor as well as the rotation speed of the rotor.This allows the converter to adjust the supply frequency according to the rotor position, to maintain an angle 9 of 90° between the rotating stator field Hs and a rotor field Hr, so that the motor torque can always be maximum.

[0004] However, in certain applications, particularly in aeronautics, it is difficult to integrate speed sensors into the rotor of the synchronous machine, particularly when the environment is very hostile or difficult for maintenance. For example, such rotation sensors must withstand high thermal stress; in particular, there are needs to use synchronous motors on aircraft that can go from a temperature of 45°C, for example on a tarmac, to a negative temperature of -70°C when the aircraft is at high altitude. In addition, these rotation sensors may be subject to other constraints, such as dust, humidity, etc. All these constraints lead to a reduction in the MTBF (Mean Time Between Failure), corresponding to the average time between failures of a repairable system.

[0005] There is also a solution for remotely measuring the angular position of the motor by measuring the EMF between phases for a given current (amplitude and phase), however this solution requires a starting sequence at a very low excitation frequency so that the motor naturally grips the rotating flux, resulting in a start with almost zero torque. It is therefore not possible to start with a starting torque.

[0006] There is therefore a need to know the angular position of the rotor and its speed, in applications of a synchronous motor in an environment hostile to rotation sensors without torque constraint at start-up. Summary of the invention

[0007] The invention offers a solution to the problems mentioned above, by making it possible to have information on the angular position of the rotor by using its magnetic influence on the inductance of the stator winding.

[0008] One aspect of the invention relates to an intelligent converter for a synchronous motor comprising: • two inputs intended to be connected to a continuous source, • at least three phase lines intended to be connected to a phase of the motor synchronous, • a rectifier inverter block comprising one arm of transistors per phase line, each connected between the two inputs and comprising an output connected to a corresponding phase line to convert the direct current at the inputs into alternating current on the corresponding phase line, • a measuring block comprising a current sensor per phase line to each measure a current in the corresponding phase line, • an intelligent control unit comprising: • a control block connected to a control of each transistor of the rectifier inverter block to control them, the control block being configured to transmit a control signal to each transistor to form, on each line, a global alternating voltage signal each comprising the superposition: • an alternating power voltage signal having a first amplitude value at a first frequency between a first and second value, • with a measurement signal having a second amplitude lower than the first amplitude and a second frequency at least 20 times higher than the second value of the first frequency, • a calculation block for estimating the angular position of the rotor comprising a first demodulator block and a second demodulator block, connected to the measurement block to receive the global current signals representative of the currents in the phase lines by the measurements of the current sensors, the calculation block for estimating the angular position of the rotor being configured to: • receive a global signal representative of the current of a line by each corresponding current sensor, • demodulate each global current signal by the first demodulator block at the second frequency, to extract at a time t, a demodulated measurement signal and identify a current value of each demodulated measurement signal, and identify two possible angular positions of the rotor as a function of the values ​​of each demodulated measurement signal at time t, • simultaneously demodulate each global signal by the second demodulator at a value of twice the second frequency to extract at a time t, a sign of a harmonic of order 2 of the current of each measurement signal, and • estimate the rotor angular position based on the harmonic sign identified among the two possible rotor angular positions identified.

[0009] Thanks to the invention, it is possible to have information on the angular position of the rotor as well as its speed without an angular position sensor and without electronics close to the synchronous motor while being able to perform a start with a torque. Indeed, the intelligent converter can be remote from the synchronous motor and therefore be placed in a regulated environment which is much less hostile to that of the synchronous motor. The synchronous machine can thus be devoid of a physical rotation sensor installed on the mechanical shaft of the rotor which are expensive, bulky and sensitive to the environment (because of mechanical oscillations, temperature, noise due to the switching of the power converter etc.).The intelligent control unit thus makes it possible to have an overall voltage on each phase output line comprising a first sinusoidal power voltage having the first frequency and a superimposed measurement voltage having the second frequency. The stator windings of the synchronous machine will produce an induced current which results from this overall voltage and the value of the impedance of each winding as a function of the position. Indeed, the rotor comprising at least one pair of poles, will in . influence the magnetic path for each stator winding according to the angular orientation of its poles thus modifying the magnetic permeability of the resulting circuit, leading to the modification of the stator inductance according to the angular position.

[0010] The current sensors each carry out measurements of the amplitudes and phases of the currents induced in the motor and since the impedance of each phase winding varies in the stator depending on the position of the rotor, the intelligent control unit can detect the position of the rotor. Indeed, thanks to the superposition of the measurement signal on the power signal, and its high frequency, the control unit can deduce by demodulating each global induced current signal, by the frequency of the control signals, two angular positions of the rotor since the control signals vary according to the inductance of the phase windings and therefore the position of the rotor.

[0011] In particular, the first demodulator makes it possible to identify two possible angular positions of the rotor and the second demodulator uses measurements of the even harmonics generated by the asymmetry, in the cycle B = f(H), by the influence of the magnetism of the rotor in order to determine to distinguish a North pole from a South pole of the rotor, and thus distinguish the possible angular position of the rotor among the two positions of the rotor determined.

[0012] In addition to the characteristics which have just been mentioned in the preceding paragraph, the intelligent converter according to one aspect of the invention may have one or more complementary characteristics among the following, considered individually or according to all technically possible combinations: • According to one embodiment, the measurement signal has a second amplitude at least 5 times lower than the first amplitude. • According to one embodiment, each transistor of the rectifier inverter block is controlled by the intelligent unit by high-frequency pulse width modulation and in that the rectifier inverter block further comprises an LC filter per phase line. This makes it possible to supply the motor with a voltage close to a sinusoidal signal. • High-frequency pulse width modulation refers to a few hundred kHz to a few MHz (i.e., between 1 and 3 MHz). This frequency range is easily filtered by the L, C filter (a capacitor and an inductor) to create pseudo-sinusoidal voltages. This limits radio frequency emissions from a three-phase cable carrying electrical energy between the converter and the electric motor. This also reduces partial discharges in the stator windings that can cause short circuits in the winding between two

[0013]

[0014]

[0015]

[0016]

[0017] conductors that have suffered damage due to partial discharges. In addition, this helps to reduce high-frequency currents in the motor's ball bearings, reducing their lifespan. • According to one embodiment, the control unit comprises a memory comprising control laws linked to the intrinsic characteristics of the synchronous motor. • According to one embodiment, the intelligent control unit comprises a memory comprising four angular position values ​​per value of an average RMS current of the demodulated measurement signal and in that the control unit identifies the two angular position values ​​common to the different values ​​of an average RMS current of the demodulated measurement signal at time t. • According to one embodiment, the first value of the first frequency is equal to 0 Hertz and the second value of the first frequency is equal to 1000 Hz. • According to one embodiment, the first and second demodulators are demodulators by synchronous modulator and in which the demodulated measurement signal is representative of the amplitudes of the RMS currents of high frequency current pulsation. According to one embodiment, the second demodulator block comprises a modulator by current sensor making it possible to verify the sign of the harmonic of order 2 of the corresponding measurement signal. Another aspect of the invention relates to a starting system comprising: • the intelligent converter according to the first aspect of the invention with or without the different characteristics described in the preceding paragraphs, and • a synchronous motor comprising a stator comprising phase outputs each connected to a corresponding phase line of the intelligent converter. According to one embodiment, the system further comprises a battery comprising two terminals each connected to a corresponding input of the smart converter. By battery, we mean one or more electrical energy storage blocks, together allowing a continuous voltage to be output between these two terminals. Another aspect of the invention relates to a method of powering the power system according to the aspect of the invention described above, comprising the steps of: • receive a speed instruction, • control the transistors of the rectifier inverter block to supply the phases of the synchronous motor, according to an overall alternating voltage signal such as that it comprises an alternating voltage power signal having a first amplitude value according to a first frequency, as a function of the speed setpoint, and furthermore a measurement signal superimposed on the power signal, the measurement signal having a second amplitude lower than the first amplitude (for example at least 10 times) and a second frequency at least 20 times higher than the second value, • transmit global current signals representative of the currents in the phase lines measured by the current sensors, • demodulate each global current signal by the first demodulator block and by the second demodulator simultaneously, • estimate at different times t an angular position value of the rotor including the sub-steps of • at each time t, measure a value for each demodulated measurement signal and identify for each demodulated measurement signal angular position values ​​corresponding to the value identified at time t, • identify two possible angular position values ​​which are common in the different angular position values ​​corresponding to the values ​​of the demodulated measurement signals different at each instant t, • identify the sign, of the value at each instant t, of each signal demodulated by the second block and estimate the angular position of the rotor relative to the stator among the two possible angular position values ​​based on at least one identified sign.

[0018]

[0019] Another aspect of the invention relates to a method for acquiring control laws linked to the intrinsic characteristics of the synchronous motor, for a power supply system according to the aspect of the invention described previously, in which a synchronous motor identical to that of the power supply system is mounted on a bench with a rotation sensor, and in that the method for acquiring control laws comprises the steps: • powering the phases of the synchronous motor by the rectifier inverter block according to the overall alternating voltage signal in which the alternating voltage power signal has a first predetermined amplitude value according to a first predetermined frequency, and • measure at different times t, an angular position value and the global current signals, • demodulate for each different instant t measured, each global signal of current into a value of each measurement signal demodulated by the first demodulator block as well as identifying the sign of each overall current signal demodulated by the second block and • store a correspondence between these demodulated measurement signal values ​​and the angular position value as well as the sign of each signal demodulated by the second demodulator block.

[0020] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0021] The figures are presented for information purposes only and in no way limit the invention.

[0022] [Fig.l] represents an electrical block diagram of a power supply system comprising an intelligent converter according to an embodiment of the invention.

[0023] [Fig.2a] represents a schematic diagram of the operation of the converter in intelligent powering a synchronous motor.

[0024] [Fig.2b] represents a representative diagram of the alternating voltages supplying the motor stator relative to one complete revolution of a rotor.

[0025] [Fig.3] represents a diagram representative of the values ​​of an impedance image of the windings of a stator as a function of the angular position of the rotor, for a complete revolution of the same rotor.

[0026] [Fig.4] represents a representative diagram of the high frequency component of the measuring currents demodulated by a demodulator block of the intelligent converter, for one complete revolution of a rotor.

[0027] [Fig.5] represents the diagram of [Fig.4] with two angular position values possible identified rotor over a complete revolution of the same rotor.

[0028] [Fig.6a] represents a block diagram of a calculation block allowing the measurement of the different harmonics composing the current carried by the stator supply lines and of the elements allowing ultimately the calculation of angular position by the control unit of the intelligent converter of [Fig.l].

[0029] [Fig.6b] represents a block diagram of an example of a calculation block of estimation of the angular position of the rotor of an intelligent control unit of the intelligent converter of [Fig.l].

[0030] [Fig.7] represents three different positions of the rotor relative to the stator as well as a graph of magnetic induction field B versus magnetic field strength B = f (H) per position, with each operating point corresponding to the position of the corresponding rotor. DETAILED DESCRIPTION

[0031] The figures are presented for information purposes only and in no way limit the invention.

[0032] [Fig.l] shows a schematic representation of a system for supplying a synchronous motor M by an intelligent converter C. The synchronous motor M comprises in this example three phases but could comprise others, for example five or six phases forming a double three-phase. In this example, the synchronous motor M comprises its phases connected in star but could be connected in delta.

[0033] The intelligent converter C comprises a phase line PI, P2, P3 per phase of the motor M, i.e. in this example a first, a second and a third phase line respectively referenced PI, P2, P3 each connected to a phase of the corresponding synchronous motor.

[0034] The intelligent converter C according to this embodiment can be remote from the synchronous machine M, for example a multi-phase cable, in this case three-phase, of several meters can connect each phase line L1, L2, L3 of the intelligent converter C to the corresponding phase of the synchronous machine M. Thus the intelligent converter C can be installed in an environment less restrictive for the electronics than the synchronous machine M. For example in an airplane, the synchronous machine can be located in an environment subject to large temperature variations, for example in the landing gear or in the turbomachine or even inside the wings of airplanes while the intelligent converter C can be installed in a cabinet for example in the fuselage having a controlled temperature.

[0035] The intelligent converter C comprises two inputs each connected to a corresponding terminal of a battery B. The voltage at the output of the battery is continuous and can be high, for example 1000V.

[0036] The intelligent converter C comprises a rectifier inverter block R between the two inputs and the phase lines PI, P2, P3.

[0037] The rectifier inverter block R comprises an arm T1, T2, T3 of transistors t per phase line PI, P2, P3, each connected between the two inputs and comprising an output connected to a corresponding phase line PI, P2, P3 to convert the direct current at the inputs into alternating current on the corresponding phase line PI, P2, P3.

[0038] In this embodiment, the rectifier inverter block R is of the conventional type but could be another type of rectifier inverter.

[0039] Each arm T1, T2, T3 of transistors t is therefore connected in parallel with the other arms T1, T2, T3 of transistors t between the two inputs. The inverter rectifier block R comprises for the first arm T1 of transistors t, a transistor t1 connected to a first so-called positive input, and a second transistor t2 connected between the first transistor t1 and the second so-called negative input. The first phase line PI is thus connected between the first transistor t1 and second transistor t2. The inverter rectifier block R thus comprises a third transistor t3 and a fourth transistor t4 forming the second arm T2 identically to the first arm T1 as well as a fifth transistor t5 and a sixth transistor t6 forming the third arm T3 identically to the first arm T1.

[0040] Furthermore, in this exemplary embodiment, the rectifier inverter block R optionally comprises a filtering block F comprising an LC filter per phase line PI, P2, P3. Each LC filter comprises an inductance FL1, FL2, FL3 on the phase line PI, P2, P3, i.e. each connected between the connection point of the two transistors t of a corresponding arm T1, T2, T3 and a phase output of the stator of the synchronous machine M. Each LC filter further comprises a capacitor FC1, FC2, FC3 connected between the corresponding phase line PI, P2, P3, and the second so-called negative input connected to the negative terminal of the battery B.

[0041] The intelligent converter C further comprises a measuring block IP comprising a current sensor IPI, IP2, IP3 per phase line PI, P2, P3 for each measuring a current II, I2, I3 in the corresponding phase line PI, P2, P3. Thus, in this example, the first current sensor IPI produces a first overall current signal Sil representative of the current II in the first phase line PL. The second and third current sensors IP2, IP3 each respectively produce a second and third overall current signal Si2, Si3 representative of the current I2, I3 in the second and third phase lines P2, P3 respectively. The current sensors may for example be of the current transformer type IT, but may be of other types such as by shunt or any other type of current sensor having sufficient bandwidth for the measurements.

[0042] The intelligent converter C further comprises an intelligent control unit U1 comprising a control block ulO connected to a control of each transistor t of the rectifier inverter block R to control them in order to form a sinusoidal voltage on each phase line PI, P2, P3. Thus the current II, 12, 13 passing through each phase line PI, P2, P3 makes it possible to supply the phases of the synchronous machine M.

[0043] The intelligent control unit U1 further comprises a calculation block for estimating the angular position of the rotor ul 1 connected to the current sensors IPI, IP2, IP3 to receive each global current signal Sil, Si2, Si3.

[0044] The intelligent control unit Ul controls, via its control block ulO, the transistors t of the rectifier inverter block R as a function of a speed setpoint and an angular position value Orl of the rotor estimated in the calculation block for estimating the angular position of the rotor ul 1.

[0045] In particular, the control block ul0 is configured to transmit a control signal to each transistor t1, t2, t3, t4, t5, t6 to form, on each line of phase PI, P2, P3, an overall alternating voltage signal VI, V2, V3 to form a three-phase network such as, for example, that shown in [Fig.2b], each comprising a superposition of two signals detailed below.

[0046] [Fig.2a] represents a schematic diagram of the operation of the intelligent converter supplying a synchronous motor.

[0047] Each global alternating voltage signal VI, V2, V3 comprises an alternating power signal V10 (referenced in [Fig.2a]) of voltage having a first amplitude value V1P according to a first frequency F1P (represented in [Fig.2b]) according to the battery voltage and the speed setpoint. For example, here the first frequency F1P is 500Hz with an amplitude of 2000 Volts (2 times 1000 volts). The control unit ul0 is configured to produce this alternating power signal of voltage V10 in a frequency range between a first minimum value and a second maximum value. In this example, the second value is equal to 500Hz, i.e. here in this example the synchronous motor rotates at the maximum speed. The synchronous motor has for example 10 pairs of poles on the stator, i.e. in this example a rotation speed of 3000 rpm.

[0048] As can be seen in [Fig.2b], each global alternating voltage signal VI, V2, V3 comprises a control signal Vil (referenced in [Fig.2a]) superimposed on the power signal. By superimposed, it is meant that each global alternating voltage signal VI, V2, V3 is a single signal comprising the two signals V10 and Vil, shown schematically separated in [Fig.2a] for better understanding but are grouped together as shown in [Fig.2b].

[0049] An enlargement of a part of the first global alternating voltage signal V1 is shown to show this superimposed measurement signal VI1. This measurement signal undulates, according to a second amplitude Vie of at least 5 times lower than the first amplitude Vlp, in this case 100 Volts or approximately 5% of the amplitude Vlp of the alternating power signal (20 times lower).

[0050] The measurement signal further has a second frequency F1C at least 20 times higher than the second value of the first frequency F1P, in this case 50 times higher, i.e. 25000 Hz.

[0051] The measurement signal has a sinusoidal shape.

[0052] When the rotor of the synchronous motor rotates, it modifies the impedance of the windings of each phase of the stator according to the angular position of the rotor. Indeed, the rotor comprising at least one pair of poles, will influence the magnetic path for each winding of the stator according to the angular orientation of its poles, therefore modifying the magnetic permeability of the resulting circuit, leading to the modification of the stator inductance according to the angular position.

[0053] [Fig.3] represents a graph representative of the values ​​of an image of impedances Ll, ​​L2, L3 of the windings of a stator as a function of the angular position of the rotor, for a complete revolution of this same rotor.

[0054] On the ordinate, we can see on the graph the impedance image L1, L2, L3 of each phase of the stator which is a function of the pulsation of the supply voltage of the phases, i.e.: [Lco(Q)], which varies for the present example in a ratio of 1 to 3.25 and on the abscissa we can see the different values ​​of angular rotation of the rotor relative to a reference point, i.e. between 1° and 360°.

[0055] The modeling of the graph in [Fig.3] makes it possible to represent an image of the inductance Z thus showing a non-purely sinusoidal variation in reluctance. This modeling is given only as an example and may be adapted to other rotor geometries:

[0056] Z = L.co = [Lo + ^.Sin^O) +k2.Sin(4a>)].œ with • ¢ = rotor angular position, 0 to 360° • (o = pulsation of the supply voltage, in our case, 25000.2ir. • The deformation is brought by the Sin(4 <e>).

[0057] This variation in the impedance of the stator windings is mainly a function of the topology of the rotor and is a function of the angular position of the rotor by the variable reluctance effect (magnetic path dependent on the position of the rotor with respect to the stator). Thus this variation in the impedance of the stator windings has an influence on the path with low relative permeability offered to the alternating magnetic field at 25,000 Hz emitted by the stator. The amplitudes of each current II, 12, 13 of each phase line PI, P2, P3 at 25,000 Hz are therefore dependent on the angular position of the rotor. The calculation block for estimating the angular position of the rotor ul 1 can therefore, from the global current signals Sil, Si2, Si3 representative of the currents II, 12, 13 in the phase lines PI, P2, P3 by the measurements of the current sensors Ip 1, Ip2, Ip3, estimate a value of the angular position of the rotor.

[0058] In this example, the rotor subsequently comprises a single pair of poles.

[0059] The calculation block for estimating the angular position of the rotor ul 1 is represented according to a block diagram in [Fig.6a] and 6b. The calculation block for estimating the angular position of the rotor ul 1 comprises a first demodulator block UH1 and a second demodulator block UH2 shown in [Fig.6b]. Each of the two demodulator blocks UH1 and UH2 demodulates each global current signal Sil, Si2, Si3.

[0060] The first demodulator block demodulates each global current signal Sil, Si2, Si3 at the second frequency F1C, to extract at a time t, a demodulated measurement signal Irmsl, Irms2, Irms3, a current value of the demodulated measurement signal Irmsl, Irms2, Irms3, represented in [Fig.4]. In this case, the value is an RMS current value from the English "root mean square".

[0061] Thus, the first demodulator block UH1 comprises a demodulator H11, H12, H13 (referenced in figures 6a and 6b) by global current signal Sil, Si2, Si3 received to bring out the harmonic component 1 of each of the three currents. Each demodulator H11, H12, H13 is as shown in [Fig.6a] and therefore includes a multiplier which thus multiplies the global current signal Sil, Si2, Si3 by the value equal to the second frequency F1C, i.e. in this example 25000 Hz to bring out the harmonics of order 1.

[0062] In this example, each demodulated measurement signal Irmsl, Irms2, Irms3 comprises four possible rotor angular positions per current value demodulated by the demodulator block UH1.

[0063] For example, the first demodulated measurement signal Irmsl corresponding to the first current II has for a current value measured at an instant t, for example here approximately equal to 100mA milliamperes, represented by a line and circles intersecting the first demodulated measurement signal Irmsl, a first value ¢11 approximately equal to 70°, a second value Orl approximately equal to 90°, a third value ¢13 approximately equal to 270° and a fourth value ¢12 approximately equal to 240° (visible in [Fig.4]).

[0064] The same applies to the second demodulated measurement signal Irms2, the value measured at time t of which is equal, for example, to 100 mA amperes, represented by a line and squares intersecting the second demodulated measurement signal Irms2, has a first value ¢21 approximately equal to 0°, a second value r 1 approximately equal to 90° a third value ¢23 approximately equal to 190° and a fourth value ¢12 approximately equal to 240° (visible in [Fig.4]).

[0065] The same applies to the third demodulated measurement signal Irms2, the value measured at time t of which is equal, for example, to 100 mA amperes, represented by a line and triangles intersecting the third demodulated measurement signal Irms2, to a first value rl approximately equal to 90°, a second value ¢32 approximately equal to 120° a third value ¢12 approximately equal to 240° and a fourth value ¢34 approximately equal to 290° (visible in [Fig.4]).

[0066] The first demodulator block UH1 comprises for example an extractor VH1, VH2, VH3 per demodulator H11, H12, H13 to extract a possible angular positioning value ¢11, rl, ¢13, ¢12, ¢21, ¢32, ¢23, ¢34 depending on the current value at time t for each demodulated measurement signal (Irmsl, Irms2, Irms3). In [Fig.6a], the position value extractor function is directly done in a common value identifier ¢H, explained below

[0067] Thus the first demodulator block UH1 measures at each instant t, a value for each demodulated measurement signal Irmsl, Irms2, Irms3 and identifies for each demodulated measurement signal Irmsl, Irms2, Irms3, angular position values ​​¢11, rl, ¢13, ¢12, ¢21, ¢32, ¢23, ¢34 corresponding to the value identified at time t.

[0068] The first demodulator block UH1 finally comprises a value identifier common OH, angular position values ​​OU, Orl, 013, Or2, 021, 032, 023, 034 identified for each value measured at time t of the demodulated measurement signals Irmsl, Irms2, Irms3.

[0069] For example, in the example of [Fig.4], at time t each demodulated measurement signal Irmsl, Irms2, Irms3 has the angular position value of the rotor Orl, Or2, extracted by the extractor respectively VH1, VH2, VH3 for each current value at time t of the demodulated measurement signal respectively Irmsl, Irms2, Irms3.

[0070] Thus the common value identifier OH makes it possible to identify these two possible angular position values ​​Orl, Or2, as shown in [Fig.5].

[0071] Thus, the second demodulator block UH2 comprises a demodulator respectively referenced H21, H22, H23 (visible in FIGS. 6a and 6b) by global current signal Sil, Si2, Si3 received to identify even harmonics, in this case in this example the harmonics of order 2. Each demodulator H21, H22, H23 comprises a multiplier which thus multiplies the global current signal Sil, Si2, Si3 by a value equal to twice the second frequency F1C, i.e. here in this example 50000 Hz.

[0072] The second demodulator block UH2 comprises a reader respectively referenced SH21, SH22, SH23 by global current signal Sil, Si2, Si3 to read each positive or negative sign of the harmonics of order 2 of each global current signal Sil, Si2, Si3. In the example shown in [Fig.6a], the reader is a comparator with the value 0.

[0073] The second demodulator block UH2 may further comprise a sign calculator, receiving from the reader, each positive or negative sign of the second order harmonics of each global current signal Sil, Si2, Si3 and in that the calculator averages the quadratic values ​​according to the different signs, to determine a value of its sign (positive or negative) of the second harmonic H2.

[0074] The rotor angular position estimation calculation block ul 1 finally comprises a rotor angular position estimator ul 10 for estimating the position value Or among the two possible angular position values ​​Orl, Or2, as a function of the positive or negative signs of the second order harmonics received by the readers. In the two examples shown in [Fig.6a] and 6b, rotor angular position estimator ul 10 performs the sign calculation function for estimating the angular position among the two possible positions received from the common value identifier OH.

[0075] In this example, the angular position Orl is equal to 90°.

[0076] Indeed, the fact that the rotor has magnets introduces an external field on the stator, causes the shift of the operating point on the function B = f(H) whose deformation of the current wave will be asymmetrical. As shown in [Fig.7] which represents three different positions of the rotor relative to the stator as well as a graph of the magnetic induction field B as a function of the magnetic field intensity B = f (H) per position, with each operating point therefore corresponding to the position of the corresponding rotor.

[0077] This asymmetry results in the appearance of even harmonics. In fact, each current II, 12, 13 circulating in each phase line PI, P2, P3 will therefore cause the shift of the operating point on the function B = f(H) whose even harmonic is dependent on the position in the cycle. That is to say that we will distort more sometimes the positive alternation, sometimes the negative alternation, depending on which side we are located around point 0 of the cycle B = f(H).

[0078] Thanks to the demodulators H21, H22, H23 and using the value of H2, by the value of its sign (positive or negative) we can know if the shift in the cycle B = f(H) is due to a North pole or a South pole of the rotor and thus deduce if the angular position of the rotor has as value the first or the second possible angular position Orl, r2.

[0079] According to an example, not shown, the calculation block for estimating the angular position of the rotor ul 1, further comprises a fourth-order demodulator, and a fourth-order harmonic reader for comparing the results with those of the second order. This makes it possible to have a significantly higher amplitude, which makes it possible to improve the sensitivity of the calculation block for estimating the angular position of the rotor ul 1, in particular when the position is close to 360°.

[0080] For motors having more than one pair of poles on the rotor, the angular position is to be calculated over 360 divided by the number of pairs of poles, i.e.: [0081 ] 180° for 2 pairs of poles

[0082] 120° for 3 pairs of poles

[0083] 90° for 4 pairs of poles

[0084] In these examples, as the rotor comprises more than one pair of poles, the angular position of the rotor is therefore not estimated over 360° but the control block ul0 controls the power supply control of the synchronous motor over 360° / by the number of pairs of poles and not over 360°.

[0085] The invention also relates to a method for supplying the supply system described above comprising the steps of: • receiving a speed instruction, • control the transistors of the rectifier inverter block R to supply the phases of the synchronous motor, according to an overall alternating voltage signal VI, V2, V3 such that it comprises an alternating voltage power signal having a first amplitude value V1P according to a first frequency Fl P, as a function of the speed setpoint, and in addition a measurement signal superimposed on the power signal, the measurement signal having a second amplitude at least 10 times lower than the first amplitude and a second frequency at least 20 times higher than the second value, • transmit global current signals Sil, Si2, Si3 representative of currents II, 12, 13 in phase lines PI, P2, P3 measured by current sensors Ip 1, Ip2, IP3, • demodulate each global current signal Sil, Si2, Si3 by the first demodulator block UH1 and by the second demodulator UH2 simultaneously, • estimate at different times t an angular position value of the rotor comprising the sub-steps of: • at each time t, measure a value for each demodulated measurement signal Irmsl, Irms2, Irms3 and identify for each demodulated measurement signal Irmsl, Irms2, Irms3 angular position values ​​¢11, Orl, ¢13, ¢12, ¢21, ¢32, ¢23, ¢34 corresponding to the value identified at time t, • identify two possible angular position values r 1, ¢12 which are common in the different angular position values ​​identified ¢11, rl, ¢13, ¢12, ¢21, ¢32, ¢23, ¢34 corresponding to the values ​​of the demodulated measurement signals Irmsl, Irms2, Irms3 different at each instant t, • identify the sign, of the value at each instant t, of each signal demodulated by the second block UH2 and estimate the angular position r 1 of the rotor relative to the stator among the two possible angular position values rl, ¢12 depending on at least one identified sign.

[0086] Finally, given that the variation in the impedance of the stator windings is mainly a function of the topology of the rotor and is a function of the angular position of the rotor by the variable reluctance effect (magnetic path dependent on the position of the rotor with respect to the stator). The invention also relates to a method for acquiring control laws linked to the intrinsic characteristics of the synchronous motor, for a power supply system described above, in which a synchronous motor identical to that of the power supply system is mounted on a bench with a rotation sensor, and in that the method for acquiring control laws comprises the steps of: • Powering the phases of the synchronous motor by the rectifier inverter block R according to the overall alternating voltage signal in which the alternating voltage power signal has a first predetermined amplitude value V1P according to a first predetermined frequency F1P, and • Measure at different times t, an angular position value and the signals global currents Sil, Si2, Si3, • demodulate for each different instant t measured, each global current signal Sil, Si2, Si3 into a value of each demodulated measurement signal Irmsl, Irms2, Irms3 by the first demodulator block UH1 as well as identify the sign of each global current signal Sil, Si2, Si3 demodulated by the second block UH2 and • memorize a correspondence between these demodulated measurement signal values ​​Irmsl, Irms2, Irms3 and the angular position value as well as the sign of each signal demodulated by the second demodulator block UH2.

[0087] Unless otherwise specified, the same element appearing in different figures has a single reference. < / e>

Claims

Claims

1. Intelligent converter (C) for synchronous motor comprising - two inputs intended to be connected to a continuous source (B), - at least three phase lines (PI, P2, P3) intended to be connected to a phase of the synchronous motor, - a rectifier inverter block (R) comprising an arm (Tl, T2, T3) of transistors (t) per phase line (PI, P2, P3), each connected between the two inputs and comprising an output connected to a corresponding phase line (PI, P2, P3) to convert the direct current at the inputs into alternating current on the corresponding phase line (PI, P2, P3), - a measuring block (IP) comprising a current sensor (IPI, IP2, IP3) per phase line (PI, P2, P3) for each measuring a current (II, 12, 13) in the corresponding phase line, and each producing a global current signal (Sil, Si2, Si3) representative of the current (II, 12, 13) in the phase lines (PI, P2, P3) measured by the current sensors (IPI, IP2, IP3), an intelligent control unit (Ul) comprising: • a control block (ulO) connected to a control of each transistor (t) of the rectifier inverter block (R) to control them, the control block being configured to transmit a control signal to each transistor to form, on each line, a global alternating voltage signal (VI, V2, V3) each comprising the superposition:

1. of an alternating power voltage signal (VIO) having a first amplitude value (V1P) according to a first frequency (FlP) between a first and second value, 2. with a measurement signal (Vil) having a second amplitude (Vie) lower than the first amplitude and a second frequency at least 20 times higher than the second value of the first frequency, a calculation block for estimating the angular position of the rotor (ul 1) comprising a first demodulator block (UH1) and a second demodulator block (UH2), connected to the measurement block (IP) to receive the global current signals (Sil, Si2, Si3) representative of the currents (II, 12, 13) in the phase lines (PI, P2, P3) by the measurements of the current sensors (Ip 1, Ip2, Ip3), the calculation block for estimating (ul 1) the angular position of the rotor ( <e>r 1 ) being configured to:

1. receive a representative global signal (Sil, Si2, Si3) of the current of a line (Ll, L2, L3) by each corresponding current sensor (Ici, Ic2, Ic3), 2. demodulate each global current signal (Sil, Si2, Si3) by the first demodulator block (UH1) at the second frequency (F1C), to extract at a time t, a demodulated measurement signal (Irmsl, Irms2, Irms3) and identify a current value of each demodulated measurement signal, and identify two possible angular positions of the rotor (Cbrl, <br2) en fonction des valeurs de chaque signal de mesure démodulé à l’instant t, 3. simultaneously demodulate each global signal by the second demodulator (UH2) at a value of twice the second frequency (fie) to extract at a time t, a sign of a harmonic of order 2 of the current of each measurement signal (Sil, Si2, Si3), and 4. estimate the angular position of the rotor ( <br) en fonction du signe d’harmonique (SH2) identifié parmi les deux positions angulaires du rotor possible identifiées (Cbrl, <hr2).

2. Intelligent converter (C) according to claim 1, wherein each transistor (t) of the rectifier inverter block (R) is controlled by the intelligent unit (Ul) by high-frequency pulse width modulation and in that the rectifier inverter block (R) further comprises an LC filter per phase line (PI, P2, P3).

3. Intelligent converter (C) according to claim 1 or 2, in which the control unit (Ul) comprises a memory comprising control laws linked to the intrinsic characteristics of the synchronous motor (M).

4. Intelligent converter (C) according to any one of the preceding claims, in which the intelligent control unit (Ul) comprises a memory comprising four angular position values (¢11,¢^¢13, ¢12, ¢21, ¢32, ¢23, ¢34) per value of an RMS current of the demodulated measurement signal (Irmsl, Irms2, Irms3) and in that the control unit (Ul) identifies the two common angular position values (¢^, ¢r2) at the different values of an RMS current of the demodulated measurement signal (Irmsl, Irms2, Irms3) at time t.

5. Smart converter (C) according to any one of the preceding claims wherein the first value of the first frequency is equal to 0 Hertz and the second value of the first frequency is equal to 1000Hz.

6. Intelligent converter (C) according to any one of the preceding claims in which the first and second demodulators (UH1, UH2) are demodulators by synchronous modulator and in which the demodulated measurement signal (Irmsl, Irms2, Irms3) is representative of the amplitudes of the RMS currents of high frequency current pulse.

7. Intelligent converter (C) according to any one of the preceding claims in which the second demodulator block (UH2) comprises a modulator (H21, H22, H23) per current sensor (IPI, IP2, IP3) making it possible to verify the sign of the harmonic of order 2 of the corresponding measurement signal (Sil, Si2, Si3).

8. Power supply system comprising: - the intelligent converter (C) one of the preceding claims, - a synchronous motor comprising a stator comprising phase outputs each connected to a corresponding phase line of the intelligent converter.

9. A method of powering the power system of claim 8, comprising the steps of: - receive a speed instruction, - control the transistors of the rectifier inverter block (R) to supply the phases of the synchronous motor, according to an overall alternating voltage signal (VI, V2, V3) such that it comprises an alternating voltage power signal having a first amplitude value (V1P) according to a first frequency (FlP), depending on the speed instruction, and in addition a measurement signal superimposed on the power signal, the measurement signal having a second amplitude lower than the first amplitude and a second frequency at least 20 times higher than the second value, - transmit global current signals (Sil, Si2, Si3) representative of the currents (II, 12, 13) in the phase lines (PI, P2, P3) measured by the current sensors (Ip 1, Ip2, IP3), - demodulate each global current signal (Sil, Si2, Si3) by the first demodulator block (UH1) and by the second demodulator (UH2) simultaneously, - estimate at different times t an angular position value of the rotor including the sub-steps of • at each time t, measure a value for each demodulated measurement signal (Irmsl, Irms2, Irms3) and identify for each demodulated measurement signal (Irmsl, Irms2, Irms3) angular position values (¢11, Orl, ¢13, ¢12, ¢21, ¢32, ¢23, ¢34) corresponding to the value identified at time t, • identify two possible angular position values (¢^, ¢12) which are common in the different angular position values identified (¢11, rl, ¢13, ¢12, ¢21, ¢32, ¢23, ¢34) corresponding to the values of the demodulated measurement signals (Irmsl, Irms2, Irms3) different at each instant t, • identify the sign of the value at each time t, of each signal demodulated by the second block (UH2) and estimate the angular position ( <brl) du rotor par rapport au stator parmi les deux valeurs de positions angulaires possibles (<br 1, <br2) en fonction d’au moins un signe identifié.

10. Method for acquiring control laws linked to the intrinsic characteristics of the synchronous motor, for a power supply system according to claim 8, in which a synchronous motor identical to that of the power supply system is mounted on a bench with a rotation sensor, and in that the method for acquiring control laws comprises the steps of: - Powering the phases of the synchronous motor by the rectifier inverter block (R) according to the overall alternating voltage signal in which the alternating voltage power signal has a first predetermined amplitude value (V1P) according to a first predetermined frequency (FlP), and - Measure at different times t, an angular position value and the global current signals (Sil, Si2, Si3), - demodulate for each different instant t measured, each global current signal (Sil, Si2, Si3) into a value of each demodulated measurement signal (Irmsl, Irms2, Irms3) by the first demodulator block (UH1) as well as identify the sign of each global current signal (Sil, Si2, Si3) demodulated by the second block (UH2) and - memorize a correspondence between these demodulated measurement signal values (Irmsl, Irms2, Irms3) and the angular position value as well as the sign of each signal demodulated by the second demodulator block (UH2). < / e>

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