Device for determining the angular position of a rotor of a rotary electric machine
Patent Information
- Application Number
- EP2023748803
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-08-02
- Filing Date
- 2023-08-01
- Publication Date
- 2025-06-11
AI Technical Summary
Existing methods for determining the angular position of a rotating electric machine rotor rely on precise sensor placement, requiring complex end-of-line calibration and are not feasible for independent equipment manufacturers, leading to potential errors and oscillations due to lack of orthogonality between sensor signals.
A device with a dynamic orthogonality fault compensation circuit that uses two sensor signals to determine and compensate for orthogonality defects, ensuring the signals are 90° offset, thereby improving rotor position estimation accuracy without the need for end-of-line calibration and addressing sensor aging and drift.
The solution enhances rotor position estimation precision dynamically, eliminating the need for complex calibration, reducing data acquisition delays, and being insensitive to electrical harmonics, while maintaining stability and accuracy across varying rotor speeds.
Smart Images
Figure 1.1
Abstract
Description
[0001] Device for determining the angular position of a rotor of a rotating electrical machine
[0002] The present invention relates to a device for determining the angular position of a rotor of a rotating electrical machine, as well as an assembly comprising such a determination device and such a rotating electrical machine.
[0003] The electrical machine is, for example, an alternator or an alternator-starter powered by a nominal voltage of 12V or 48V, or even higher. The electrical machine can also be a propulsion machine powered by a nominal voltage of 12V or 48V, or even higher, for example a voltage greater than 300V, for example 400V or 800V.
[0004] This electric machine can be integrated into a vehicle with hybrid or purely electric propulsion, for example an automobile. More generally, “vehicle” encompasses, within the meaning of this application, any form of mobility with purely electric, hybrid, thermal or other propulsion. “Vehicle” thus encompasses a machine rolling on land via four, three, two wheels or any other number of wheels, or a machine moving in the air or on water, or even in space.
[0005] Controlling this electrical machine requires knowledge of the angular position of the machine's rotor. To do this, it is known, in the case of a three-phase synchronous machine, to use two signals provided by sensors, for example Hall effect, inductive type or at the end of the shaft, signals which are offset by 90° (electrical or mechanical), depending on the type of sensor. The signals provided by these sensors are processed by a rotor position estimation circuit, for example via a control loop. This circuit provides an output signal representative of this rotor position. This measurement can then be used, for example, to control the inverter / rectifier interposed between the stator of this electrical machine and the electrical energy storage unit of the vehicle's on-board network, which is notably a battery.
[0006] The accuracy of the position obtained at the output of the rotor position estimation circuit depends, among other things, on compliance with the 90° value for the angular, or phase, offset between the two signals provided by the position sensors. A lack of orthogonality of this offset, which is consequently different from 90°, is for example caused by imprecise positioning of the sensors on the electrical machine. However, an offset different from 90° can generate errors on the second harmonic, for example, of the signal representing the rotor position ultimately obtained, ultimately leading to current and torque oscillations in the electrical machine.
[0007] To avoid such problems, it is known to carry out an end-of-line calibration operation, just before the electric machine is delivered to the customer. However, such an end-of-line calibration operation is complex and time-consuming, relying for example on an iterative extraction of Fourier series carried out at constant speeds which are then subject to complex processing. Furthermore, and above all, such an end-of-line calibration operation is not possible when the electric machine is supplied by an equipment manufacturer independently of its power and control electronics.
[0008] There is therefore a need to remedy the aforementioned drawbacks.
[0009] The invention achieves this, according to one of its aspects, by means of a device for determining the angular position of a rotor of a rotating electrical machine on the basis of only two sensor signals provided by position sensors, the device comprising:
[0010] - a circuit estimating the position of the rotor, in particular via the creation of a control loop, this circuit providing at output a signal representative of the position of the rotor, and
[0011] - a dynamic orthogonality defect compensation circuit between a first input signal from one of the two sensor signals supplied by the position sensor(s) and a second input signal from the other of the two sensor signals supplied by the position sensor(s), this orthogonality defect compensation circuit receiving at least the first and second input signals as input, this orthogonality defect compensation circuit providing at output a signal transmitted to the circuit estimating the position of the rotor, providing in particular an input of the circuit estimating the position of the rotor, this orthogonality defect compensation circuit being configured to:
[0012] - dynamically determine on the basis of the first and second input signals the value of the orthogonality defect between these two signals,
[0013] - construct a compensation matrix on the basis of this orthogonality defect value thus determined, and
[0014] - compensating for the lack of orthogonality between said input signals by applying this compensation matrix to said input signals.
[0015] The invention makes it possible to compensate for the orthogonality defect resulting from the position sensors used, and this other than via an end-of-line calibration operation. At the output of the orthogonality defect compensation circuit, two signals can be obtained whose fundamentals are offset by 90°. This orthogonality defect compensation is carried out upstream of the circuit estimating the position of the rotor, so that the latter then receives as input two signals whose fundamentals are offset by 90°. The invention is based on dynamic compensation, so that it makes it possible to detect, and even correct, any position drift resulting from the aging of the machine. Although an end-of-line calibration operation is not necessary with the invention, the invention can make it possible, when such an operation is carried out, to verify that it has been carried out correctly.
[0016] The improvement in the accuracy of the signal representing the rotor position is obtained according to the invention using a simple solution, which is implemented in the determination device upstream of the circuit estimating the rotor position, in particular via a control loop. Furthermore, this solution has the following advantages:
[0017] - not to require oversampling,
[0018] - not to generate a delay in data acquisition, and therefore not to cause a risk of instability,
[0019] - not to involve a complex adaptive frequency filter,
[0020] - not to involve trigonometric functions or complex cross-correlations
[0021] - not to require imposing a constant speed on the machine for a significant period of time, as required by a calibration operation at the end of the line,
[0022] - not to be a static solution, but a dynamic one.
[0023] The solution according to the invention can provide the advantage of not involving a state observer, such as for example a Kalman filter.
[0024] The solution according to the invention can also provide the following advantages:
[0025] - be insensitive to electrical harmonics
[0026] - be decorrelated from the bandwidth of the circuit estimating the rotor position,
[0027] The signal representing the rotor position is, for example, an angle value relative to a reference position. This can be the angle characterizing the electrical position or the angle characterizing the mechanical position of the rotor of the electrical machine.
[0028] The orthogonality defect compensation circuit is arranged upstream of the rotor position estimation circuit, in particular via the creation of a control loop. The output of the orthogonality defect compensation circuit is, for example, directly received at the input of the rotor position estimation circuit.
[0029] The number of sensor signals may be equal to the number of position sensors, for example, a position sensor providing only one sensor signal. Alternatively, the number of sensor signals may be different from the number of position sensors. For example, in the case where the sensors are used in differential mode, the number of position sensors is twice the number of sensor signals. Where appropriate, the angular offset between the sensor signals may be equal, within the ratio of the number of pole pairs, to the angular offset between sensors from which these sensor signals originate. The angular offset between the sensor signals may be equal to the angular offset between sensors from which these sensor signals originate.
[0030] The orthogonality error compensation circuit can dynamically determine the orthogonality error related to the mechanical angular offset between the two sensor signals provided by the position sensors. This is the case, for example, when these sensors are shaft-end sensors.
[0031] Alternatively, the orthogonality mismatch compensation circuit can dynamically determine the orthogonality mismatch due to the electrical angular offset between the two sensor signals provided by the position sensors. This is the case, for example, when the position sensors are inductive, Hall effect, or resolvers.
[0032] In all of the above, the dynamic determination of the orthogonality defect between the first and second input signals may include:
[0033] - the multiplication of the first and second input signals and the application of a first filter, in particular low-pass, to the signal resulting from this product,
[0034] - the sum of the square of the first input signal and the square of the second input signal and the application of a second filter, in particular low-pass, to the signal resulting from this sum.
[0035] The output of the first filter can be proportional to the square of the amplitude and the sine of the orthogonality defect between the first and second input signals.
[0036] Taking into account the signal at the output of the second filter can reduce the impact of a calculation error made at the input of the first filter. This consideration can also improve the response time in transient conditions.
[0037] The first filter and the second filter may be different, the first filter being for example a filter of order 3 or order 2 and the second filter being in particular a filter of order 2 or 1, at least one of the first and second filters being in particular a Butterworth filter.
[0038] Alternatively, the first and second filters may be identical, each being a 1st order, 2nd order, or 3rd order filter. Each of these first and second filters may be implemented as a Butterworth filter.
[0039] Each of the first filter and the second filter is, for example, a low-pass filter. As we will see later, these filters can have a constant cutoff frequency or a variable cutoff frequency. For the same instant, or even for any instant, the cutoff frequency can be the same between the first filter and the second filter.
[0040] The output of the first filter can be divided by the output of the second filter. The signal resulting from this division can drive a saturation block, providing a simple way to improve accuracy during the transient regime.
[0041] In all of the above, the compensation matrix can be a 2*2 matrix, at least two of its coefficients being a function of the orthogonality defect.
[0042] The compensation matrix has for example as coefficients
[0043] [Math. 1] y(y where (p corresponds to the orthogonality defect between the first and second input signals as determined.
[0044] In the theoretical case where the value determined for the orthogonality defect between the first and second input signals would be zero, we see that this compensation matrix would be the identity matrix h
[0045] In all of the above, the compensation of the orthogonality defect can be carried out for any rotor rotation speed.
[0046] Alternatively, in all of the above, the compensation for the orthogonality defect is only performed for a rotor rotation speed range, the orthogonality defect compensation circuit also receiving the rotor rotation speed as input. This rotor rotation speed is for example obtained at the output of the circuit estimating the rotor position. The compensation for the orthogonality defect is for example only performed above a minimum rotor rotation speed. Below this minimum rotation speed, which is for example 100, 200, 300, 400, 500, 600 or 700 rpm, no compensation for the orthogonality defect between the first and second signals is then performed, and these first and second signals are directly transmitted to the circuit estimating the rotor position. Not performing orthogonality compensation for low speeds can avoid the need to use overly selective low-pass filters.
[0047] Whether or not the compensation for the orthogonality defect is carried out over the entire operating range of the machine, when the first filter and the second filter are each a low-pass filter, the cut-off frequency of each filter can vary as a function of the speed. This cut-off frequency can vary continuously or discontinuously, then successively occupying constant values. Varying each cut-off frequency, or at least one of these two cut-off frequencies such as that of the first filter only or that of the second filter only, can make it possible to achieve a compromise between precision and speed of the response of the orthogonality defect compensation circuit.For example, higher first and second filter cutoff frequencies for lower speeds allow the value of the orthogonality defect to be determined quickly, while lower cutoff frequencies for higher speeds improve accuracy.
[0048] In all of the above, the circuit estimating the position of the rotor can implement a control loop and subtract from the output signal of this control loop a position error signal determined on the basis of the lack of orthogonality between the first and second input signals.
[0049] In all of the above, the device may also comprise a dynamic normalization circuit by the amplitude of the first harmonic of each sensor signal provided by the position sensor(s), this dynamic normalization circuit providing output signals to the orthogonality defect compensation circuit, providing in particular the first and second input signals of the orthogonality defect compensation circuit. This dynamic normalization circuit is thus arranged upstream of the orthogonality defect compensation circuit. This dynamic normalization circuit is for example produced according to the teaching of application WO2021 / 121770.
[0050] The invention also relates, according to another of its aspects, to an assembly comprising:
[0051] - a rotating electrical machine for the propulsion of a hybrid or electric vehicle, and
[0052] - a control device for this electrical machine, comprising a determination device as defined above.
[0053] The rotating electrical machine is, for example, a synchronous machine, for example, a three-phase synchronous machine or a synchronous machine whose stator electrical winding defines a double three-phase system. The stator electrical winding is, for example, formed by wires or by conductive bars connected to each other.
[0054] In all of the above, the rotor may be a claw rotor. This rotor then comprises a first and a second nested pole wheel, the first pole wheel defining a series of claws of generally trapezoidal shape, each claw extending axially towards the second pole wheel, the second pole wheel defining a series of claws of generally trapezoidal shape, each claw extending axially towards the first pole wheel. A permanent magnet may be received between two consecutive claws circumferentially speaking for the rotor.
[0055] Alternatively, the rotor may be other than a claw rotor, for example comprising a lamination pack or being a cage rotor. In all of the above, the rotor may comprise any number of pole pairs, for example three, four, six or eight pole pairs.
[0056] In all of the above, the electrical machine may include a stator cooling circuit in which fluid such as air or liquid circulates. This liquid may be water or oil.
[0057] The rotor can be cooled by this same cooling circuit or by another cooling circuit in which air, or liquid such as water or oil, circulates.
[0058] The electric machine may have a mechanical rated power of between 4 kW and 35 kW, being for example 4 kW, 8 kW, 15 kW, 25 kW or 35 kW, or the electric machine may have a mechanical rated power of between 40 kW and 400 kW, being for example 40 kW, 80 kW, 100 kW, 150 kW, 180 kW, 200 kW, 300 kW or 400 kW.
[0059] This rotating electrical machine can be electrically powered from an electrical energy storage unit via an inverter / rectifier of the assembly, this inverter / rectifier allowing, depending on whether the electrical machine operates as a motor or as a generator, to charge an on-board network of the vehicle or to be electrically powered from this network.
[0060] The nominal voltage of the electrical energy storage unit can be 12 V, 48 V or have another value, for example another value higher than 300 V.
[0061] The rotating electrical machine may also include a pulley or any other means of connection to the rest of the vehicle's powertrain. The electrical machine is, for example, connected, in particular via a belt, to the crankshaft of the vehicle's thermal engine. Alternatively, the electrical machine is connected to other locations in the powertrain, for example, at the input of the gearbox from the point of view of the torque transmitted to the vehicle's wheels, at the output of the gearbox from the point of view of the torque transmitted to the vehicle's wheels, at the gearbox from the point of view of the torque transmitted to the vehicle's wheels, or on the front axle or the rear axle of this powertrain.
[0062] The rotating electrical machine is not necessarily a synchronous machine, but can be an asynchronous machine.
[0063] The invention also relates, according to another of its aspects, to a method for determining the angular position of a rotor of a rotating electrical machine on the basis of only two sensor signals provided by position sensors, in which a determination device as defined above is used.
[0064] All or part of what has been mentioned above still applies to this other aspect of the invention.
[0065] This determination method is for example integrated into a method for controlling the electric machine, in which the angular position of the rotor determined as above is used to control the motor torque and / or the current of the electrical energy storage unit.
[0066] This determination method can be implemented by a computer program product, which, when read by the electrical rotating machine control device, makes it possible to implement the steps of carrying out said method, said computer program product being able to be stored on a medium readable by said control device.
[0067] The invention may be better understood by reading the following description of a non-limiting example of its implementation and by examining the attached drawing in which:
[0068] [Fig.l] schematically represents in axial section an example of a rotating electrical machine to which the invention can be applied,
[0069] [Fig.2] shows in elevation another type of rotor than that of figure 1
[0070] [Fig.3] schematically represents the device for determining the position of the rotor of the machine according to a non-limiting example of implementation of the invention, [Fig.4] schematically represents in detail an example of implementation of the orthogonality defect compensation circuit,
[0071] [Fig.5] schematically represents a detail of figure 4,
[0072] [Fig.6] to [Fig.8] represent examples of filters that can be used to realize the part of the compensation circuit of figure 5,
[0073] [Fig.9] schematically represents another detail of figure 4,
[0074] [Fig.10] schematically represents yet another detail of Figure 4, and
[0075] [Fig.11] corresponds to response curves allowing an effect of the invention to be illustrated.
[0076] Figure 1 shows a polyphase rotating electrical machine 1, in particular for a motor vehicle, to which the invention can be applied.
[0077] This rotating electrical machine can form an alternator or an alternator-starter of the vehicle. This rotating electrical machine can be powered via a power electronic component 9 comprising an inverter / rectifier by a battery whose nominal voltage is 12 V or 48 V or a value greater than 300 V, for example.
[0078] The rotating electrical machine 1 comprises a casing 2. Inside this casing 2, it further comprises a shaft 3, a rotor 4 integral in rotation with the shaft 3 and a stator 5 surrounding the rotor 4. The rotational movement of the rotor 4 takes place around an axis X. In this example, the casing 2 comprises a front bearing 6 and a rear bearing 7 which are assembled together. These bearings 6, 7 are hollow in shape and each centrally carry a respective ball bearing 10, H for the rotational mounting of the shaft 3.
[0079] A pulley 12 is in the example considered fixed on a front end of the shaft 3, at the level of the front bearing 6, for example using a nut resting on the bottom of the cavity of this pulley. This pulley 12 makes it possible to transmit the rotational movement to the shaft 3 and it can be connected via a belt to the crankshaft of the thermal engine of the vehicle.
[0080] The rear end of the shaft 3 carries, here, slip rings belonging to a collector and connected by fasteners to the winding. Brushes belonging to a brush holder 8 are arranged so as to rub on the slip rings.
[0081] The front bearing 6 and the rear bearing 7 may further comprise substantially lateral openings for the passage of air in order to allow the rotating electrical machine to be cooled by air circulation generated by the rotation of a front fan 13 on the front dorsal face of the rotor 4, i.e. at the level of the front bearing 6 and of a rear fan 14 on the rear dorsal face of the rotor, i.e. at the level of the rear bearing 7.
[0082] In this embodiment, the stator 5 comprises a body 15 in the form of a stack of sheets provided with notches, for example of the semi-closed or open type, equipped with notch insulation for mounting the polyphase electrical winding of the stator. Each phase comprises a winding 16 passing through the notches of the body 15 and forming, with all the phases, a front bun and a rear bun on either side of the body of the stator. The windings 16 are for example obtained from a continuous wire covered with enamel or from bar-shaped conductive elements such as pins connected together. The electrical winding of the stator is for example three-phase, then implementing a star or delta assembly whose outputs are connected to the power electronic component 9.
[0083] The rotor 4 of Figure 1 is a claw rotor. It has two pole wheels 17. The first pole wheel 17 is turned towards the power electronic component 9 while the second pole wheel 17 is turned towards the pulley 12.
[0084] Each of the pole wheels 17 comprises a base 18 extending radially on either side of the axis X, the wheel defining a series of claws 19 of generally trapezoidal shape. Each claw of a pole wheel 17 extends axially towards the other pole wheel from a base arranged on the radially outer periphery of the base 18.
[0085] The rotor 4 also comprises, between the radially inner portions 20 and the claws 19, a coil wound on a coil insulator 22.
[0086] The rotor 4 may also comprise permanent magnets (not shown) interposed between two neighboring claws 19 at the outer periphery of the rotor. Alternatively, the rotor 4 may be devoid of such permanent magnets.
[0087] The rotor 4 may also be different from that shown in Figure 1, being for example formed by a stack of sheets, as shown in Figure 2.
[0088] The number of pole pairs defined by the rotor 4 can be any, for example three, four, six or eight.
[0089] The machine also comprises sensors 20 for measuring the position of the rotor 4, for example two Hall effect sensors, grouped in the same plastic housing and arranged so as to have between them an electrical angular offset equal to 90°. One of these sensors provides a first sensor signal “S” being here a sine signal, and the other of these sensors provides a second sensor signal “C” being here a cosine signal.
[0090] These sensors are for example positioned at the rear bearing 7 of the machine and they interact with a magnetic target rotating with the rotor.
[0091] The sensor signals S and C are used by a control device of the rotating electrical machine 1, comprising a device 100 for determining the angular position of the rotor 4. The control device of the rotating electrical machine 1 may be a computer, for example a microcontroller, or an integrated circuit, for example an FPGA or an ASIC, capable of receiving electrical signals and processing them, in particular the sensor signals 20.
[0092] The two signals S and C provided by these two sensors 20 are used by the device 100 for determining the angular position of the rotor 4, which will now be described with reference to figures 3 and following.
[0093] In a known manner, the device 100 comprises a circuit 101 performing dynamic compensation of the biases (“offset” in English) by averaging the samples.
[0094] In the example of Figure 3, the output signal of this circuit 101 drives a dynamic normalization circuit 105 by the amplitude of the first harmonic of each signal from a position sensor 20. This circuit 105 is for example as described in application WO2021 / 121770. As can be seen in Figure 3, the circuit 105 also receives as input an output from a dynamic orthogonality defect compensation circuit 102 which will be described later. One of the signals at the output of the circuit 105 and coming from the first sensor signal S constitutes a first input signal 200 for the dynamic orthogonality defect compensation circuit 102, and another signal at the output of the circuit 105 and coming from the second sensor signal C constitutes a second input signal 201 for this circuit 102.As will be described later, the circuit 102 dynamically compensates for the orthogonality defect between the first input signal 200 and the second input signal 201, which orthogonality defect is identical to that between the first sensor signal S and the second sensor signal C.
[0095] In an example not shown, the circuit 105 is not present, so that the output signal of the circuit 101 is received as is at the input of the dynamic orthogonality defect compensation circuit 102.
[0096] As can be seen in Figure 3, the dynamic orthogonality defect compensation circuit 102 can also, but in a non-limiting manner, receive as input the rotation speed of the rotor as estimated at the output of a circuit 103 which will be described later.
[0097] In addition to an output signal received at the input of the circuit 105, there are at the output of the dynamic orthogonality defect compensation circuit 102 two signals 204 and 205 respectively coming from the first 200 and the second 201 input signal, these two signals 204 and 205 being angularly offset by 90°. In the case where the first input signal 200 has the expression
[0098] [Math. 2] S=sin(omega*t) and where the second input signal 201 has the expression [Math. 3] C=cos(omega*t+phi), the signals 204 and 205 then have the expression [Math. 4] S=sin(omega*t) and [Math. 5] C=cos(omega*t) respectively.
[0099] These two signals 204 and 205 are received at the input of the circuit 103 estimating the position of the rotor, this circuit 103 providing at the output a signal 206 representative of the position of the rotor 4, by means of an angle 0 measured relative to a reference position of this rotor. This angle corresponds in the example described to the electrical angle characterizing the position of the rotor 4, but could alternatively correspond to the mechanical angle characterizing this position. This circuit 103 here implements a control loop of the position of the rotor 4.
[0100] Also at the output of the circuit 102 is a position error signal 207 determined by the circuit 102 on the basis of the orthogonality defect between its first 200 and its second 201 input signal. As can be seen in Figure 3, this position error signal 207 is subtracted from the signal 206 to provide the signal representative of the rotor position at the output of the device 100.
[0101] The circuit 103 is for example identical to that described in the application WO2021 / 121770 already cited.
[0102] The dynamic orthogonality defect compensation circuit 102 will now be described in more detail in Figures 3 to 6. As can be seen in Figure 3, this circuit 102 also receives as input, in addition to the output signals from circuit 105, or where appropriate from circuit 101 directly, an output 208 from circuit 103, namely the signal representative of the speed of rotor 4.
[0103] The operation of an exemplary dynamic misalignment compensation circuit 102 will now be described.
[0104] As can be seen in Figure 3, this dynamic orthogonality defect compensation circuit 102 comprises:
[0105] - a block 220 making it possible to dynamically determine, on the basis of the first 200 and the second 201 input signals, the value of the orthogonality defect between these two input signals,
[0106] - a block 221 for constructing a compensation matrix based on this orthogonality defect value thus determined, and
[0107] - a block 222 for compensating for the orthogonality defect between said input signals 200 and 201 by applying this compensation matrix to said input signals 200 and 201.
[0108] An example of a dynamic determination block 220 will be described with reference to Figure 4. This block 220 receives as input:
[0109] - the first 200 and the second 201 input signal of the dynamic compensation circuit 102,
[0110] - a filter cut-off frequency value generated by a block 224 itself receiving as input the signal 208 representative of the rotation speed of the rotor at the output of the circuit 103,
[0111] - an initialization value 209 for the orthogonality defect between the first and second signals. This initialization value may be 0° or between -10° and 10°, in particular between -1° and 1°, being for example of the order of 0.5° or -0.5°,
[0112] - an initialization value 210 for the outputs of filters 212 and 213.
[0113] This block 220 applies two separate treatments to the first signal 200 and to the second signal 201.
[0114] According to a first processing, the first signal 200 is multiplied with the second signal 201 and the resulting product is processed by a first low-pass filter 212 whose cut-off frequency value is provided by the block 224. Below a minimum rotation speed, which is for example 100, 200, 300, 400, 500, 600 or 700 rpm, the block 224 can neutralize the block 220 so that the input signals 200 and 201 are transmitted as is at the output of the dynamic orthogonality defect compensation circuit 102.
[0115] According to a second processing, the first signal 200 is squared, the second signal 201 is squared, and the sum of these two squares is processed by a second low-pass filter 213 whose cutoff frequency is identical to that of the first low-pass filter. Each of the first filter 212 and the second filter 213 is for example a low-pass filter. The first filter 212 and the second filter 213 may be different, the first filter being for example a filter of order 3 or order 2 and the second filter being in particular a filter of order 2 or 1, at least one of the first and second filters being in particular a Butterworth filter. Alternatively, the first 212 and the second 213 filters may be identical, each being a filter of order 1, order 2 or order 3. Each of this first and second filter example may be implemented in the form of a Butterworth filter.
[0116] Each of the low-pass filters may have a cutoff frequency that varies depending on the rotor rotation speed. For example, this frequency varies piecewise, taking higher values for low rotation speeds and decreasing stepwise as the rotation speed increases. For any instant, the cutoff frequency is, for example, the same between the first filter 212 and the second filter 213.
[0117] Alternatively, each filter 212 and 213 may have a constant cutoff frequency.
[0118] Figures 6 to 8 show examples of filters that can constitute the first filter 212 or the second filter 213. Each of the filters 212, 213 uses, for example, one of the solutions according to one of Figures 6 to 8.
[0119] As can be seen in Figure 5, in the example described, the output of the first filter 212 is divided by the output of the second filter 213. The signal resulting from this division drives a saturation block 215, making it possible in a simple manner to improve the accuracy of the determination of the orthogonality defect by the block 220 during the transient regime. At the output of this saturation block 215, a gain 216 can then be applied, here a gain of value “-2”, the value of this gain being advantageously chosen so that at the output of this gain the value of the orthogonality defect between the first input signal 200 and the second input signal 201 is obtained exactly.
[0120] This block 220 has an output 217 which drives the block 221 for constructing the orthogonality defect matrix which is shown in Figure 9. The output 217 corresponds to the value determined by the block 220 for the orthogonality defect cp between the first signal 200 and the second signal 202. The example in Figure 9 is such that the compensation matrix at the output of the block 221 is a 2*2 matrix, the coefficients of which are the
[0121] As can be seen in Figure 5 and as already indicated previously, the output 217 of the block 220 is received at the input of the dynamic normalization circuit 105. The output 217 of the block 220 is also, in the example considered, received at the input of a block 223 which is represented in Figure 10. This block 223 applies in this example a gain, the value of which is for example 1 / 2, to the value determined for the orthogonality defect, and the output of this block 223 provides the signal 207 which has already been mentioned with reference to Figure 3.
[0122] Block 222 consists of applying to the first signal 200 and to the second signal 201 at the input of the dynamic compensation circuit 102 the compensation matrix generated by block 221. At the output of this block 222, signals 204 and 205 are obtained which are angularly offset by 90° and which attack circuit 103.
[0123] Figure 11 represents on the same time scale on the abscissa on a graph 300 the evolution of the rotation speed of the rotor of the electrical machine as provided by the device 100,
[0124] - on a graph 301 the evolution of the signals at the input of the circuit 102 for compensating for orthogonality defect, each coming from one of the position sensors 20,
[0125] - on a graph 302 the evolution of the value determined by the block 220 of the circuit 102 for the orthogonality defect between the first input signal 200 and the second input signal 201; and
[0126] - on a graph 303 the evolution of the rotor position error
[0127] In this example, the two sensor signals from sensors 20 have an electrical offset not equal to 90° but with an orthogonality defect of 7°.
[0128] The dynamic orthogonality defect compensation circuit 102, an example of implementation of which has been described above, is started at an instant to.
[0129] We observe by observing:
[0130] - curve 302 that the value of 7° is obtained for the orthogonality defect between the input signals in less than 100ms,
[0131] - curve 303 that the position error is cancelled out in the same time interval, and
[0132] - curve 300 that the estimated rotation speed improves after compensation for the orthogonality defect, as evidenced by the disappearance of the second harmonics. The invention is not limited to the implementation example which has just been described.
[0133] In particular, the dynamic orthogonality defect compensation circuit 102 can act independently of the rotational speed of the rotor, i.e. from the start of the electrical machine. In the latter case, the cut-off frequency of each filter 212 and 213 can remain constant. Alternatively, in the latter case, the cut-off frequency of each filter 212 and 213 can vary, as described previously.
[0134] The implementation of the determination of the angular position of the rotor 4 can be carried out by a computer program product, which, when executed by the control device of the rotating electrical machine 1, makes it possible to carry out the method of determining the angular position of the rotor 4 of the rotating electrical machine 1 on the basis of the two sensor signals 20 provided by position sensors, as described with reference to Figures 3 to 11.
[0135] This computer program product can be recorded on a storage medium readable by the control device in order to carry out the implementation of the determination of the angular position of the rotor 4.
Claims
Claims 1. Device (100) for determining the angular position of a rotor (4) of a rotating electrical machine on the basis of only two sensor signals (S, C) provided by position sensors (20), device comprising: - a circuit (103) estimating the position of the rotor, in particular via the creation of a control loop, this circuit (103) providing at output a signal representative of the position of the rotor, and - a circuit (102) for dynamic compensation of orthogonality defect between a first input signal (200) from one of the two sensor signals provided by the position sensor(s) (20) and a second input signal (201) from the other of the two sensor signals provided by the position sensor(s) (20), this circuit (102) for compensation of orthogonality defect receiving as input at least: the first (200) and the second (201) input signal, this circuit (102) for compensation of the orthogonality defect providing as output a signal transmitted to the circuit (103) estimating the position of the rotor, providing in particular an input of the circuit (103) estimating the position of the rotor, this circuit (102) for compensation of the orthogonality defect being configured to: - dynamically determine on the basis of the first and second input signals the value of the orthogonality defect between these two signals, - construct a compensation matrix based on the value of this defect thus determined, and - compensating for the lack of orthogonality between said input signals (200, 201) by applying this compensation matrix to said input signals.
2. Device according to claim 1, in which the dynamic compensation circuit (102) dynamically determines the orthogonality defect due to the mechanical angular offset between the two sensor signals provided by the position sensors (20).
3. Device according to claim 1, in which the dynamic compensation circuit (102) dynamically determines the orthogonality defect linked to the electrical angular offset between the two sensor signals provided by the position sensors (20).
4. Device according to any one of the preceding claims, in which the dynamic determination of the orthogonality defect between the first (200) and the second (201) input signal comprises: - the multiplication of the first (200) and the second (201) signal and the application of a first filter (212), in particular low-pass, to the signal resulting from this product, - the sum of the square of the first signal (200) and the square of the second signal (201) and the application of a second filter (213), in particular low-pass, to the signal resulting from this sum.
5. Device according to the claim, in which the first filter (212) and the second filter (213) are different, the first filter (212) being for example a filter of order 3 or of order 2, and the second filter (213) being in particular a filter of order 2 or 1, at least one of the first (212) and the second filter (213) being in particular a Butterworth filter.
6. Device according to claim 4 or 5, wherein the output of the first filter (212) is divided by the output of the second filter (213).
7. Device according to any one of the preceding claims, in which the passage matrix is a 2*2 matrix, at least two of its coefficients being a function of the orthogonality defect (cp).
8. Device according to any one of the preceding claims, in which the compensation for the orthogonality defect is carried out for any rotation speed of the rotor.
9. Device according to any one of claims 1 to 7, in which the compensation for the orthogonality defect is only carried out for a range of rotation speed of the rotor, the dynamic orthogonality defect compensation circuit (102) also receiving the rotation speed of the rotor as input.
10. Device according to any one of claims 4 to 6 and according to claim 9, each of the first filter (212) and the second filter (213) being a low-pass filter, and the cut-off frequency of each filter (212, 213) varying as a function of the speed, in particular decreasing when the speed increases.
11. Device according to any one of the preceding claims, in which the circuit (103) estimating the position of the rotor implements a control loop and subtracts from the output signal of this control loop a position error signal determined on the basis of the lack of orthogonality between the first and the second input signal.
12. Device according to any one of the preceding claims, further comprising a circuit (105) for dynamic normalization by the amplitude of the first harmonic of each sensor signal coming from a position sensor (20), this circuit providing output signals to the circuit (102) for dynamic compensation of orthogonality defect, providing in particular the first and second input signals of the circuit (102) for dynamic compensation of orthogonality defect.
13. Set comprising: - a rotating electrical machine for the propulsion of a hybrid or electric vehicle, and - a device for controlling this electrical machine, comprising a determination device (100) according to any one of the preceding claims.
14. Method for determining the angular position of a rotor (4) of a rotating electrical machine on the basis of only two sensor signals provided by position sensors (20), in which a determination device (100) according to any one of claims 1 to 12 is used.
15. Computer program product comprising instructions which cause the assembly according to claim 13 to execute the steps of the method according to claim 14.
16. Computer-readable medium, on which the computer program product according to claim 15 is recorded.