Title of Invention

SENSOR SYSTEM AND METHOD FOR THE VECTOR CONTROL

Abstract

The invention relates to a sensor system for the vector control of an electric synchronous motor comprising a stator and a multi-pole rotor by means of microprocessor, the electric synchronous motor being a winding drive motor of a yam feeding device, characterised in that a plurality of sector permanent magnets having equal polarities provided regularly distributed about 360° for being driven rotatably by the rotor, that at least two stationary Hall sensors are aligned to the orbit of the sector permanent magnets, that the Hall sensors are distant from each other in orbiting direction such that each sector permanent magnet at least preliminarily activates at least two of the Hall sensors at the same time, and that, in addition, a zero point permanent magnet having reversed polarity with respect to the equal polarities of the sector permanent magnets is provided for passing at least at one of the Hall sensors when being rotatably driven by the rotor.

Full Text

The invention relates to a sensor system and a method for the vector control of an electric synchronous motor. Permanent magnet motors have proved to be advantageous drive sources in cases where among other things the rotary speeds vary strongly and stoppages are needed, since permanent magnet motors allow a very precise torque control and operate with good efficiency, i.e. with moderate power consumption and low heat emission. For the so-called vector control of permanent magnet motors either one sensor for the angular speed is needed in combination with three position sensors for the angular position of the rotor, or the required information is roughly determined by calculation with the help of parameters measured during operation. The permanent magnet motor known from EP 1 052 766 A operates without position sensors. The information on the angular speed and the angular positions for carrying out the vector control are determined by evaluating the current in the phases which currents are measured by means of a shunt resistor. The zero crossings of the electro-motoric counterforce then are used as reference times. PCT/EP 02/10700 proposes a permanent magnet motor which is excited according to a sinusoidal course and operates without position sensors by calculating the respective rotor rotary position by means of the measured electro-motoric counterforce which is induced in the stator windings by the rotor, in order to carry out the permanent vector control. In a permanent magnet motor known from US 4,814,677 A, which does not have position sensors, the voltage or the current for the windings is monitored in order to control the voltage signals or current signals via a three-phase/two-phase converter. Permanent magnet motors cannot be operated optimally in case of specific operation conditions, e.g. when, as mentioned, it has to cope with significantly different rotaiy speeds and resting or stopping phases. An optimal vector control with optimum efficiency or optimum torque is difficult for each rotary speed in case of very strong varying rotary speeds. In case of frequent stoppages a time delay has to be taken into consideration for each restart before the actual rotor rotary angle is retrieved such that the vector control again can be carried out in an optimum fashion. A particular problem is caused by external forces which tend to turn the rotor, e.g. in a stoppage phase, in the preceding rotary direction forwards or even backwards. This specific problem means that then the actual rotor rotary angle is not known any longer. These drawbacks are particularly undesirable for winding drive motors for yam feeding devices which are frequently subjected during resting phases to external forces of elastic components in the yam feeding device and/or of the yam, or if the winding element intentionally or accidentally is turned by hand. It is an object of the invention to provide a sensor system as well as method for vector control which allow to avoid these drawbacks. The sensor system has to provide precise information, particularly during stopping phases or in case of a low restarting speed in order to allow an optimum vector control without time delays. An important aspect is to provide a sensor system as well as a method for a vector control particularly for a permanent magnet motor used as a winding drive of a yam feeding device and so that the permanent magnet motor can perform with its inherent positive operational properties in an optimal fashion even under the complex requirements of the yam feeding process. As the sector permanent magnets activate the Hall sensors even during a stoppage of the motor and also during a restart and even in case of very low speed, the microprocessor is on hold at any time with the help of the zero point signal of the information which sector within the 360° of the rotor circumference is located at the Hall sensors. This information is also available during a stoppage. Additionally, the microprocessor is capable of deriving the correct rotary direction information from the at least temporary overlap between the actual angular signals, even in the case of external forces which turn the rotor during stoppage, such that the microprocessor is in the position to optimally adjust the stator vector. In other words, the microprocessor is capable of following a rotation of the rotor caused by an external force. Moreover, during a restart and in case of low motor rotary speed immediately the correct rotary angle information is available which allows an optimum vector control. The sensor system is particularly expedient for the vector control of a permanent magnet motor implemented as a winding drive of a yarn feeding device where frequently unexpected external forces may act, particularly during a stoppage. The method is expedient for an optimum vector control, particularly for the permanent magnet motor used as a winding drive of a yarn feeding device, because the method determines at any time at least the information on the sector which is positioned in front of the Hall sensor and which precisely follows rotary movements of the rotor caused by external forces, and which also recognises the sense of rotation such that the stator vector can be adjusted optimally and without delay for the restart of the motor. Expediently a digital and an analogous Hall sensor are provided. Both Hall sensors respond to the sector permanent magnets. The zero point permanent magnet activates during a passage the analogous Hall sensor the signal of which represents a reference rotary angle such that the microprocessor is informed at the occurrence of each actual angular signal which sector has reached the Hall sensors. In an alternative embodiment two digital Hall sensors are provided for the sector permanent magnets while for the zero point permanent magnet a third analogous or instead a digital Hall sensor is provided. This simplifies a correct signal evaluation. A relatively high resolution is achieved by twenty-four sector permanent magnet motors defining respective sectors of 15°. The number of the sector permanent magnets may be higher or lower and indirectly depends on the number of poles of the motor. In order to facilitate the signal evaluation for the microprocessor the Hall sensors should be connected to separated ports. Particularly expedient is an additional program part provided in the microprocessor by which program part the rotor rotary angle is determined for the vector control by means of motor run depending variations of electro-motoric forces. The program part is provided in combination with a program part intended to switchover between two evaluation routines in dependence from speed. Only during a stoppage and during a restart are the Hall sensor signals evaluated while the variations of the electro-motoric forces then are ignored. Above a predetermined motor running speed, to the contrary, the signals of the Hall sensors are ignored while only variations of the electro-motoric forces are scanned. In this way an optimum vector control is possible within a wide rotary speed range and also during a restart from standstill. Although the permanent magnets and the Hall sensors may be incorporated in the motor, it may be even more expedient to provide the permanent magnets at a carrier which is coupled to the rotor in order not to have to modify the basic concept of the motor. Furthermore, interferences between the permanent magnets and the magnets in the motor and the Hall sensors can be prevented reliably. In case of a permanent magnet motor serving as the winding drive motor of a yarn feeding device the rotor is coupled by means of a shaft with the winding element which either is a winding disc or a winding drum. The permanent magnets are arranged at the winding element while the Hall sensors are provided in the yarn feeding device in the vicinity of the orbit of the permanent magnets. The precise information which is obtained for the permanent vector control of the permanent magnet motor then may be used in addition by the microprocessor in order to adjust the winding element into at least one predetermined rotary position whenever the permanent magnet motor is stopped. This rotary position may be expedient for secondary functions in the yarn feeding device, e.g. for an automatic threading of a new yarn. Furthermore, the permanently retrieved information may be used to prevent a backward rotation of the rotor in some cases under forces produced by the yarn, by generating a holding torque with a magnitude which inhibits the winding element from rotating backwards or forwards. The microprocessor expediently is contained in a yarn feeding device control controlling the permanent magnet motor which yarn feeding device control as well is connected to a yarn supply sensor needed for control of the winding drive motor in dependence from the size of the yarn supply. The signals of the yarn supply sensors determine whether the winding drive motor has to be driven or stopped or accelerated or decelerated, respectively. During a stoppage and during operation the information provided by the permanent magnets and the Hall sensors are used by the microprocessor for controlling the motor and/or for secondary functions in the yarn feeding device. In order,to optimise the vector control for a rotary speed range of maximum width and at the same time for a restart from standstill, according to the method the stator vector is varied in case of a motor speed exceeding a predetermined motor speed value while the Hall sensor signals are ignored. The variation or rotation of the stator vector is carried out in dependence from variations of the electro-motoric forces, particularly of the counter forces caused by the rotor in the stator (e.g. PCT/EP 02/10700) and/or by measuring the voltage or the current in the windings of the stator (e.g. US 4,814,677 A). To the contrary, during a stoppage and during a restart the stator vector is adjusted by taking the Hall sensor signals into consideration. Several differing signal combinations are generated within each sector which signal combinations are read by the microprocessor as a code which informs the microprocessor on the direction of rotation and on the respective sector, in association with the zero point signal. Furthermore, the microprocessor is capable of deriving in addition as further information even further rotor rotary angle positions within the respective sector from the different signal combinations. In this way a higher resolution is achieved by the codes during the detection of the positions and in relation to the number of permanent magnets. On the other hand, the higher resolution offers the possibility to reduce the number of the sector permanent magnets or to increase the size of the sectors, respectively. An embodiment of the invention will explained with the help of the drawing. In the drawing is: Fig. 1 a longitudinal section of a permanent magnet motor used as a winding drive motor of a yarn feeding device, Fig. 2 a cross-section of the yarn feeding device of Fig. 1, Fig. 3 a diagram illustrating one type of a position detection, Fig. 4 a diagram illustrating another type of a position detection, Fig. 5 a table of the signal evaluation in the microprocessor, and Figs 6 a table illustrating a result of the signal evaluation of Fig. 3. The yarn feeding device F shown in Figs 1 and 2 is a weft yarn feeding device for a weaving machine. However, the invention also can be applied in yarn feeding devices for knitting machines (not shown) which e.g. comprise a rotatable yarn storing drum as the winding element. Furthermore, the invention is applicable even for other yarn processing machines. The yarn feeding device F in Figs 1 and 2 comprises a housing 1 with a housing bracket 2 containing additional components. A hollow shaft 3 is rotatably supported in bearings 4 in the housing 1. A storage drum D is stationarily held by the free end of the shaft 3 below the housing bracket 2. In order to prevent that the storage drum D rotates with the shaft the permanent magnets 12 are stationarily arranged in the housing for magnetic cooperation through a winding element W with not shown permanent magnets arranged in the storage drum D. An electric synchronous motor, particularly a permanent magnet motor PM, serves as an electric winding drive motor. The motor includes a rotor R provided on the shaft 3 and stator part ST. The stator part ST e.g. is fixed by a positioning part 13 (Fig. 2) in a predetermined relative rotary position in the housing 1. In the embodiment shown an electric motor control device CU and a microprocessor MP are contained in the housing bracket 2. The motor control device CU has a signal transmitting connection with a yarn supply sensor 8 for controlling the rotary speed, the torque and the resting phases of the permanent magnet motor PM, e.g. depending on the size of the yarn supply which is formed of yarn windings on the storage drum D. Furthermore, a yarn threading track 9 is provided in the housing bracket 2 which cooperates with a not shown on-board pneumatic threading device in order to thread a new yarn. A withdrawal opening 7 for the yarn also is placed at the housing bracket 2. The permanent magnet motor PM is vector controlled by the microprocessor MP by means of a sensor system SS, i.e., an electromagnetic vector is generated in the stator part ST which vector is adjusted in rotary direction with a respective optimum angular advance in relation to a vector generated by the rotor. In addition, the microprocessor MP may be provided with a program part for a vector control with the help of scanned variations of electro-motoric forces, particularly of the counter forces generated by the rotor and/or with the help of measurements of the voltage or the current, respectively, in the stator windings, and also with a program part for switching between one sort of vector control (for speeds exceeding a predetermined running speed) and the vector control using the sensor system SS (in resting phases and for restart phases). The winding element W is provided on the shaft 2 and has an exit 6. The rotary angle position of the exit 6 is structurally fixed with respect to the rotor R. In this case the winding element W is a funnel-shaped disc 10 and contains a winding tube which is not shown in detail and which ends at the exit 6. The not shown yarn is pulled in through the shaft 3 and is wound by the exit 6 in adjacent windings on the storage drum D. The sensor system SS comprises sector permanent magnets 11 which are associated to the rotor R and which sub-divide the rotor R into equal sectors within 360°. The sector permanent magnets 11 are arranged, in the shown embodiment, e.g. at the outer circumference of the funnel-shaped disc and with regular circumferential distances, e.g. twelve sector permanent magnets 11. There may be more, e.g. twenty-four, or fewer sector permanent magnets 11 than shown. All sector permanent magnets 11 have the same polarity, e.g. such that the north pole is directed outwardly, while the south pole is facing the shaft 3. At least two Hall sensors H1, H2 are associated in a stationary arrangement to the orbit of the permanent magnets 11. The Hall sensors are arranged with a relative offset in the orbiting direction. The Hall sensors H1, H2 may be digital and/or analogous Hall sensors. In case of two Hall sensors H1, H2 one of them operates digitally and the other analogously. In case of three Hall sensors (not shown) two of them operate digitally and the third one operates analogously or digitally. Fig. 2 illustrates the geometrical distribution of permanent magnets P which define poles in the rotor R. The stator part ST is shown in schematic illustration only (without the stator windings contained therein). In addition, at least one zero point permanent magnet 14 is placed e.g. in the sector number 1 and in the winding element W, expediently in the middle between two of the sector permanent magnets 11. The polarity of the additional zero point permanent magnet 14 is reversed in relation to the polarity of the sector permanent magnets 11 which all have the same polarities (the south pole of the zero point permanent magnet 14 faces outwardly while the north pole is oriented towards the shaft 3). A permanent vector control of the permanent magnet motor PM is carried out by the speed - control device CU and the microprocessor MP and by means of the sensor system SS. In this case the rotary position of the rotor R is determined permanently and the stator vector is allowed to rotate by a corresponding current supply to the stator windings such that the desired speed and an optimum development of the torque result. The information at least on the respective angular position of the rotor R in relation to the stator winding or the stator part ST and the housing 1, respectively, as needed for the vector control are retrieved by means of the sensor system SS from the co-operation between sector permanent magnets 11 (as well as the zero point permanent magnet 14) and the Hall sensors H1, H2, even in a resting phase or during a stoppage. This information even may be used for a position control and/or a position observation of the winding element W in relation to the housing 1, e.g. in order to stop the exit 6 always in alignment to the yarn threading track 9 when the permanent magnet motor PM is stopped. In Fig. 2 the winding element W has to be stopped at the predetermined rotary position X1 in a threading position relative to the housing 1, e.g. in the case of a detected yarn breakage. It may even be adjusted to a second rotary position X2 (Fig. 2) for the winding element W when the permanent magnet motor M has to be stopped, in which second rotary position the exit 6 e.g. will be offset by 90° in relation to the housing bracket 2. The information on the rotary angle position of the rotor R which is permanently available from the sensor system SS, in some cases even combined with information on the sense of rotation, also may be used to prevent a rotation of the winding element W from the adjusted stopping position e.g. X1, X2, in case of a pulling back force of the yarn. This is carried out with the help of the speed control device CU which builds up a holding torque via the permanent magnet motor PM in the respective suitable direction of rotation in order to hold the winding element W stationary. From the co-operation between the sector permanent magnets 11 and the Hall sensors H1, H2 even during a stoppage of the permanent magnet motor PM the rotary position of the rotor R is available in order to allow to then immediately carry out an optimum vector control during a restart of the permanent magnet motor PM. The permanent magnets 11,14 could also be arranged on another carrier which is coupled for rotation with the rotor R, and in some cases very close to the axis of rotation (higher resolution). The sensor system SS with the microprocessor MP and the permanent magnets 11 or 11 and 14, respectively, which co-operate with the Hall sensors H1, H2 basically also could be used for the vector control of a motor in an application other than in a yarn feeding device. The method of the vector control of the permanent magnet motor PM with the help of the sensor system SS and by the microprocessor MP is explained with the help of Figs 2 to 6. For the explanation the assumption is made that not only twelve (as shown in Fig. 2) but even twenty-four sector permanent magnets 11 are provided which define the sectors number 1 to 24, with the zero point permanent magnet placed in the sector number 1. The input ports of the microprocessor MP which are connected with the Hall sensors H1, H2 are indicated by H1\ H2\ H2", An arrow T indicates a clockwise rotation, and an arrow T an anticlockwise rotation. The microprocessor reads the signals of the Hall sensors H1, H2 at its input ports H1\ H2\ H2" as a code representing the respective sector and the current sense of rotation, e.g. as a binary or dual system code consisting of the numbers 1 and 0, corresponding e.g. to a high or a low signal level. On the basis of this information the stator vector as needed for the desired direction of rotation and the required torque is adjusted in optimal fashion. A diagram shown in Fig. 3 indicates how the microprocessor MP is reading the signals at its input ports H1 \ H2' which are generated by the sector permanent magnets 11 and zero point permanent magnet 14 in the Hall sensors H1, H2. The vertical lines in the diagram separate the respective sectors from each other. The digital Hall sensor H1 generates rectangular signals each of which is separated in the middle by a vertical separation line. The analogous Hall sensor H2 generates hill-shaped signals each of which is shorter than a sector, starting at the vertical separation line and terminating about in the middle of the sector. Furthermore, the analogous Hall sensor H2 generates in the sector number 1 (S1) in addition a hill-shaped downwardly oriented signal from the passage of the zero point permanent magnet 14. This signal continues the signals of the sector permanent magnet 11 and is situated about in the middle of the sector number 1 (S1). The rectangular signals and the positive hill signals overlap each other respectively starting at the separation line and for a range corresponding to half of the length of each rectangular signal. The diagram in Fig. 4 indicates how the microprocessor MP at its separate input ports H1\ H2\ H3 reads the signals of the three digital Hall sensors H1, H2, H3 which are provided in this case. The Hall sensor signals are rectangular signals among which the signal (lower signal train) of the zero point permanent magnet 14 is a negative rectangular signal (because of the reversed polarity). The rectangular signals of the Hall sensors H1, H2 overlap each other within a range corresponding approximately to half of the longitudinal extension of each rectangular signal, the overlap starting at the vertical separation line between the respective sectors. The rectangular signal of the Hall sensor H3 is situated in the middle part of the sector number 1 (S1). The microprocessor MP reads from the signal sequences of Figs 3 and 4, i.e. from sector signal combinations which are different among each other, a binary or a dual system code from which can be derived in association to the signal of the zero point permanent magnet 14 at least the respective sector which is placed in front of the Hall sensor, and even the sense of rotation. As there are several signal combinations in each sector which differ from each other, the microprocessor is capable of not only deriving the respective sector, but even in addition may derive discrete rotor angular positions within each sector in order to increase the resolution during the detection of the positions. This will be explained in more detail. The higher resolution even allows to reduce the number of sector permanent magnets (saving). Corresponding to the table in Fig. 5 the assumption is made that the permanent magnet motor PM has to be stopped and then has to be rotated slowly until the zero point permanent magnet 14 will activate the Hall sensor H2 and will generate at the input port H2' a signal having a high signal level = number 1. The microprocessor MP then reads the angular position of the sector No. 1. During the decelerating further rotation in the direction T of the rotation (entrance into the section No. 1) first both Hall sensors H1, H2 are not activated (they generate low signal levels = numbers 0/0 corresponding to the number 0 in the dual system). Consecutively the sector permanent magnet 11 of the sector No. 1 activates the Hail sensor H1 such that a high signal level (= number 1) will be present at the input HV while at the input H2' still a low signal level (= number 0) will be present. Therefrom the microprocessor determines in the dual system from 1/0 the number 2. Thereafter the sector permanent magnet 11 will simultaneously activate both Hall sensors HI, H2 such that a respective high signal level will be present at the input ports H1\ H2' (corresponding to the numbers 1/1 = number 3 in the dual system). Next, the sector permanent magnet 11 leaves the Hall sensor H1 which then emits a low signal level (= number 0) while the Hall sensor H continuously generates a high signal level (= number 1). Therefrom, the microprocessor reads in the dual system from 0/1 the number 1, before both Hall sensors H1, H2 will no longer be activated such that the microprocessor then will register again the number 0 in the dual system. During this passage the microprocessor determines the code 02310 out of which the microprocessor also gains a confirmation of the clockwise direction T of the rotation. Furthermore, now the microprocessor knows that the rotor R will now enter the sector No. 2 within which the rotor R will stop together with the sector permanent magnet 11 of the sector No. 2 with a simultaneous activation of both Hall sensors H1, H2 corresponding to the number 3 within the binary code 02310. For the restart of the motor now the microprocessor MP has the information that the rotor R has stopped with the sector No. 2 between both Hall sensors H1, H2 and that the rotor has come to this position in the clockwise direction T of rotation. Now the stator vector is optimally adjusted in the clockwise direction T of rotation with an advance to the rotor vector in order to initiate the restart. The microprocessor MP so to speak is following the rotational movement of the rotor R and by this, permanently also of the winding element W in view of the respective sector and the direction of rotation. This can be carried out up to the maximum rotary speed. In some cases, however, above a predetermined running speed value of the rotor it is switched over to another kind of vector control for which switching action the microprocessor MP contains a respective program routine, such that then above this speed value the vector control is carried out with the help of the scanning variations of the electro-motoric forces, particularly of the backwards acting electro-motoric force of the rotor vector in the windings of the stator and/or by measuring the voltage or the current, respectively, in the stator devices. For the sake of simplicity next the assumption is made that the rotor R has stopped during the clockwise rotation (direction T) precisely with the zero point permanent magnet 14 in front of the Hall sensor H2 such that a high signal level (corresponding to the number 1) is present at the input port H2" of the microprocessor and such that the information is present that the rotor has stopped precisely between the sectors No. 24 and No. 1. Now the assumption is made that an external force, e.g. a pulling back force of the yarn or the force manually produced by a person is acting in the counterclockwise direction T of rotation which force intentionally or accidentally tens to turn the winding element W. This external force has the result that the rotor is rotated back counter to the clockwise direction, e.g. through the sector No. 24 into the sector No. 23. During this backturn movement the microprocessor reads at the input ports H2\ H1' the numbers 0/1/1/0/0 and also 0/0/1/1/0, such that the binary code 01320 is derived. Already with the occurrence of the sequence of the numbers 01 ... in the binary code the microprocessor is informed that the counterclockwise direction T of rotation is present. Furthermore, the microprocessor reads from the combinations of zeros and ones the respective rotary angle position or the sector number, respectively, in which then the rotor has stopped, in order to again optimally adjust the stator vector for a restart in the correct clockwise direction T of rotation. Alternatively, the microprocessor may be equipped with a program routine which upon occurrence of such a backturn motion counter to the normal direction of rotation (here T in clockwise direction) immediately adjusts the stator vector such that a low torque is built up which turns the rotor back into the previous stopping position (between the sectors No. 24 and No. 1) or which is just sufficient to counteract upon detection of the tendency of a backturn rotation such that the rotor substantially remains at the first registered stopping position. As long as the rotor R is rotated in the counterclockwise direction T of rotation the microprocessor reads the binary code 01320 in association to the sector numbers, and in contradiction to the already read binary code 02310 in case of the normal direction T of rotation and also in association to the sector numbers. Fig. 4 again shows how the microprocessor continuously determines a code at the input port H1\ H2' from the signals of the Hall sensors H1, H2 which code consists in case of the clockwise direction T of rotation of the numbers 02310 in the dual systems, but in case of the counterclockwise direction T of rotation of the number sequence 01320 in the dual system. Expediently, the microprocessor then considers only the number sequence 231 or 123 in order to derive the information on the rotary angle position and of the direction of rotation. Instead of only two Hall sensors H1, H2 even three Hall sensors (Fig. 4) could be provided each of which is connected with a separate input port of the microprocessor. Among those Hall sensors the third Hall sensor either is a digital one (as shown) or an analogous Hall sensor for co-operation with the zero point permanent magnet 14, With respect to the embodiment shown in Fig. 2 then the microprocessor MP would be informed in case of the shown stopping position of the rotor R and upon activation of both Hall sensors H1, H2 that the stoppage has occurred at the number 3 in the number sequence 231, that the preceding direction of rotation was the direction T, and that the sector No. 3 is positioned between both Hall sensors H1, H2. In case that during the stoppage an external force should rotate the rotor R further then the microprocessor MP will know with the help of the number 1 and the number 0 in the binary code that the rotor R has been rotated further in the normal direction T of rotation into an angular position between the sectors number 3 and number 4. However, if the number 2 follows the number 3 in the binary code and during the stoppage in sector number 3 and if then the number 0 will follow, then the microprocessor MP will know that the rotor R has been turned back in the wrong counterclockwise direction T of rotation into a position between the sectors No. 3 and No. 2. The information derived from the Hall sensors H1, H2 also may be used to stop and fix the winding element W precisely either an the angular position X1 or X2, respectively, e.g. in order to then carry out certain threading processes (automatic threading or manual threading) without problems. With the help of the signals generated by the Hall sensors H1, H2 the permanent magnet motor PM even can be driven intentionally with the optimised vector control in the direction T of rotation. This is expedient because yarn feeding devices have to run in one or the other direction of rotation, depending on the twist of the processed yarn, in order to optimally process the yarn. In the shown embodiment the rotor R is equipped with four poles P. In this case totally twelve sector permanent magnets 11 may be expedient (sector size 30°). However, twenty-four sector permanent magnets 11 are better (sector size 15°). Among other factors the number of sectors is selected depending on the number of poles of the rotor and/or the stator windings. The higher the number of poles the smaller the sectors ought to be in order to achieve a high resolution. Since the code 02310 or 01320 is derived for each sector from signal combinations of the Hall sensors H1, H2 which are different from each other there also could be derived by the microprocessor MP further rotor angular positions within each sector from the numbers contained in the code or from the signal combinations in order to achieve in comparison to the number of sector permanent magnets 11 provided a higher resolution during the position detection of the rotor R. A sector of 15° e.g. is dividable into single smaller angular steps in order to gain very precise rotor rotation angle information for the correct adjustment of the stator vector. WE CLAIM: 1. A sensor system (SS) for the vector control of an electric synchronous motor comprising a stator (ST) and a multi-pole rotor (R) by means of microprocessor, the electric synchronous motor being a winding drive motor of a yarn feeding device (F), characterised in that a plurality of sector permanent magnets (11) having equal polarities provided regularly distributed about 360° for being driven rotatably by the rotor (R), that at least two stationary Hall sensors (HI, H2) are aligned to the orbit of the sector permanent magnets (11), that the Hall sensors (HI, H2) are distant from each other in orbiting direction such that each sector permanent magnet (11) at least preliminarily activates at least two of the Hall sensors (HI, H2) at the same time, and that, in addition, a zero point permanent magnet (14) having reversed polarity with respect to the equal polarities of the sector permanent magnets (11) is provided for passing at least at one of the Hall sensors (HI, H2) when being rotatably driven by the rotor (R). 2. The sensor system as claimed in claim 1, wherein one digital and one analogous Hall sensor (HI, H2) are provided, and that the zero permanent magnet (14) is arranged for a passage at least at the analogous Hall sensor (HI, H2). 3. The sensor system as claimed in claim 1, wherein there are provided two digital Hall sensors (HI, H2) and a third analogous or digital Hall sensor for the zero point permanent magnet (14). 4. The sensor system as claimed in claim 1, wherein there are provided twenty-four sector permanent magnets (11). 5. The sensor system as claimed in claim 1, wherein the Hall sensor (HI, H2) are connected with separated microprocessor input ports. 6. The sensor system as claimed in claim 1, wherein the rotor angle is determined by the microprocessor during a higher speed evaluation routine with the help of motor run depending variations of electro-motoric forces or of measurements of the voltage or the current in the stator winding, and that the microprocessor depending on the motor speed switches between a Hall sensor signals evaluation routine associated to a stoppage of the motor, to the restart of the motor and to low motor speeds, and the higher speed evaluation routine. 7. The sensor system as claimed in claim 1, wherein the sector permanent magnets (11) are provided at a carrier which is coupled to the rotor (R). 8. The sensor system as claimed in claim 7, wherein the rotor (R) is coupled via a shaft (3) to a winding element (W) of the yarn feeding device (F), that the winding element (W) either is a winding disc (10) with an integrated winding tube on the hollow shaft (3) or is a winding drum on the shaft (3), and that the sector permanent magnets (11) and the zero point permanent magnet (14) are arranged at the winding element (W) with the Hall sensors (HI, H2) arranged in the yarn feeding device in the vicinity of the winding element (W). 9. The sensor system as claimed in claim 1, wherein the microprocessor (MP) is contained in a yam feeding device control for the permanent magnet motor (PM), the yam feeding device control (CU) being connected at least to a yam supply sensor (8). 10. The sensor system as claimed in claim 1, wherein the electric synchronous motor is a permanent magnet motor. 11. A method for the vector control of an electric synchronous motor comprising a stator and a multi-pole rotor by using a microprocessor for adjusting the stator vector in dependence from the rotor rotary angle, the electric synchronous motor being a winding drive motor of a yam feeding device characterized in that actual angle sector signals are generated with a timewise overlap in association to a zero point signal with the help of at least two Hall sensors (HI, H2) and a plurality of sector permanent magnets (11) under use of the rotor rotation and/or the relative rotor rotary position, and that the microprocessor continuously derives the direction of rotation and the respective sector in the form of a binary or a dual system code from the actual angle sector signals for the vector control. 12. The method as claimed in claim 11, wherein the actual angle sector signals are ignored at a speed exceeding a predetermined motor run speed and that then the stator vector is adjusted in dependence from variations of the electro-motoric forces, in particular of the counter forces induced by the rotor in the stator and/or by means of the voltage or the current, respectively, measured in the stator windings. 13. The method as claimed in claim 11, wherein the code for each sector is derived from several differing Hall sensor signal combinations, and that in addition different rotor rotation angles are derived within each sector from the Hall sensor signal combinations.

Documents:

0989-chenp-2005 abstract duplicate.pdf

0989-chenp-2005 claims duplicate.pdf

0989-chenp-2005 description (complete) duplicate.pdf

0989-chenp-2005 drawings duplicate.pdf

989-chenp-2005-abstract.pdf

989-chenp-2005-claims.pdf

989-chenp-2005-correspondnece-others.pdf

989-chenp-2005-correspondnece-po.pdf

989-chenp-2005-description(complete).pdf

989-chenp-2005-drawings.pdf

989-chenp-2005-form 1.pdf

989-chenp-2005-form 18.pdf

989-chenp-2005-form 26.pdf

989-chenp-2005-form 3.pdf

989-chenp-2005-form 5.pdf

989-chenp-2005-pct.pdf