DE102017109770A1 - Method for operating a reluctance motor - Google Patents

Abstract

The invention relates to a method for operating a reluctance motor (1), comprising the steps:
Detecting (100) the intermediate circuit voltage (Ud) of a drive circuit (2) of the reluctance motor (1),
Calculating (200) a conduction region (LB) for controlling the reluctance motor (1) by the actuation circuit (2),
Comparing (300) the detected intermediate circuit voltage (Ud) with a first upper limit value (G1) of the intermediate circuit voltage (Ud) and preferably, in the case of reaching or exceeding the first upper limit value (G1), with a second upper limit value (G2) DC link voltage (Ud), and
In the case of the undershooting of the first upper limit value (G1) of the intermediate circuit voltage (Ud) by the detected intermediate circuit voltage (Ud),
o driving (500a) of the reluctance motor (1) by the drive circuit (2) with the calculated conduction area (LB), otherwise
In the case of reaching or exceeding the first upper limit value (G1) or preferably a second upper limit value (G2) of the intermediate circuit voltage (Ud) by the detected intermediate circuit voltage (Ud),
◯ reducing (400) of the calculated conduction region (LB) to an adapted conduction region (LB ') as a function of the intermediate circuit voltage (Ud), and
◯ driving (500b) of the reluctance motor (1) by the drive circuit (2) with the adapted guide area (LB ').

Description

The invention relates to a method for operating a reluctance motor according to the patent claim 1 , a reluctance drive according to claim 9 and an electrical device with such a reluctance drive according to the claim 10 ,

In the field of electric drives, the reluctance motors (SRM) are known in which the torque in the rotor is generated exclusively by the reluctance force. Therefore, neither stator nor rotor of a reluctance motor must be equipped with permanent magnets nor are there electrical windings on the rotor. Instead, the rotor has distinct poles and is usually made of a highly permeable, soft magnetic material such as an electrical sheet. As a result, reluctance motors can be produced comparatively favorably and simply. In principle, any type of wear-prone slip rings and brushes are also eliminated, which gives reluctance motors a comparatively high degree of robustness.

Reluctance motors are usually carried out multi-phase or multi-stranded and have a different number of pronounced teeth on the rotor and stator. The stator teeth are wound with coils which are alternately switched on and off or supplied with pulse width modulated current pulses (PWM current pulses). The teeth with the energized windings each attract the nearest teeth of the rotor like an electromagnet and are de-energized when or just before the teeth of the rotor face the stator teeth attracting them. In this position, the next phase is switched to the next in the direction of rotation stator teeth, so that the rotor teeth are attracted by the next in the direction of rotation stator teeth.

To switch the windings of the individual strands at the right time or to energize, usually a rotor position sensor is provided as a sensor to determine the position or angular position of the rotor relative to the stator can. This angle information of the sensor is usually used to control the energization of the lines of the reluctance motor, so that the stability of the control can be ensured even under torque fluctuations. Such torque fluctuations can occur due to external influences on the load on the output side of the reluctance motor.

If, for example, the reluctance motor is used to drive the impeller of the blower of a vacuum cleaner, a sudden interruption of the air flow by closing the suction opening or a sudden admission of the air flow by opening the suction opening on the impeller of the fan can interfere with the operation of the reluctance motor. In addition, a condition can occur in which the air column oscillates in the hose of the vacuum cleaner, which can result in a swinging angle error, which is sometimes positive, sometimes negative. Such disturbances must be compensated by the control in order to avoid damage or destruction of the drive circuit of the reluctance motor can.

For this purpose, as already mentioned, it is customary and known to use a rotor position sensor, so that the information about the position of the rotor relative to the stator can be included in the regulation as the actual value of the angular position.

The disadvantage of using a rotor position sensor as a sensor that this causes additional effort and additional costs. These are, on the one hand, the material costs of the sensor itself and, on the other hand, the material costs of the electrical wiring of the sensor, which can be regarded as the harness of the sensor. Furthermore, the sensor and its wiring harness are to be manufactured.

A further disadvantage is that a sensor may be susceptible to contamination, to mechanical loads due to vibrations and sensitive to the coupling of electromagnetic interference (EMC). All this can lead to a temporary or permanent failure of the sensor or to a temporary or permanent disturbance and distortion of the sensor signal and thus the measured angular position. As a result, the control can be disturbed in such a way that the reluctance motor can no longer be safely operated in the event of a fault despite sensor-related control.

To dispense with a rotor position sensor and to avoid the associated costs and the other potential disadvantages, encoderless method for controlling a reluctance motor are known in which the current position of the rotor relative to the stator is determined or estimated from other information.

A disadvantage of using an estimated angular position is that an encoderless control using an estimated angular position usually does not have the dynamics of a sensor-related control. This can lead to the fact that the dynamics of the system of reluctance motor and driven load can not be controlled safely in all situations. Especially with fast changing loads of driven load may occur between the estimates of the sensorless process and the actual rotor position, an angular error, so that consequently a correct angular energization of the lines of the reluctance motor can no longer be guaranteed. If this angle error were ignored and the control of the reluctance motor continued by the encoderless control, stable operation of the reluctance motor can not take place and the drive circuit of the reluctance motor can be destroyed.

The background of this destruction of the drive circuit of the reluctance motor is that the reluctance motor is to be operated in the motor mode. In this operating state, the energy flow has the direction that the electrical energy from the network passes through the diode rectifier in the DC link capacitor and then in the reluctance motor, so that the reluctance motor, for example. can drive the impeller of the blower of a vacuum cleaner. However, if the control of the reluctance motor does not take place with the correct angle, it may happen that the reluctance motor is temporarily operated as a generator instead of as a motor. The energy flow reverses, so that the rotational energy of the impeller and rotor of the reluctance motor is fed into the DC link capacitor due to the wrong control. Since a diode rectifier is not regenerative, this excess electrical energy can not be delivered to the grid. It comes to a charge of the DC link capacitor. This can be so high that the drive circuit of the reluctance motor is thereby destroyed.

The invention thus has the problem of providing a method for operating a reluctance motor, so that a stable operation of a sensorless control using an estimated angular position can be achieved. At a minimum, an alternative procedure should be provided.

According to the invention, this problem is solved by a method having the features of patent claim 1, by a reluctance drive having the features of patent claim 9 and by an electrical device having the features of patent claim 10. Advantageous embodiments and further developments of the invention will become apparent from the following subclaims.

• • Erfassen der Zwischenkreisspannung einer Ansteuerungsschaltung des Reluktanzmotors,
• • Berechnen eines Leitbereichs zur Ansteuerung des Reluktanzmotors durch die Ansteuerungsschaltung,
• • Vergleichen der erfassten Zwischenkreisspannung mit einem ersten oberen Grenzwert der Zwischenkreisspannung und vorzugsweise, im Falle des Erreichens oder Überschreitens des ersten oberen Grenzwerts, mit einem zweiten oberen Grenzwert der Zwischenkreisspannung, und
• • im Falle des Unterschreitens des ersten oberen Grenzwerts der Zwischenkreisspannung durch die erfasste Zwischenkreisspannung,
  • ◯ Ansteuern des Reluktanzmotors durch die Ansteuerungsschaltung mit dem berechneten Leitbereich, sonst
• • im Falle des Erreichens oder Überschreitens des ersten oberen Grenzwerts oder vorzugsweise des zweiten oberen Grenzwerts der Zwischenkreisspannung durch die erfasste Zwischenkreisspannung,
  • ◯ Verringern des berechneten Leitbereichs zu einem adaptierten Leitbereich in Abhängigkeit von der Zwischenkreisspannung, und
  • ◯ Ansteuern des Reluktanzmotors durch die Ansteuerungsschaltung mit dem adaptierten Leitbereich.

Thus, the present invention relates to a method for operating a reluctance motor with the steps:

• Detecting the DC link voltage of a drive circuit of the reluctance motor,
• Calculating a conduction region for driving the reluctance motor by the drive circuit,
• Comparing the detected intermediate circuit voltage with a first upper limit value of the intermediate circuit voltage and preferably, in the case of reaching or exceeding the first upper limit value, with a second upper limit value of the intermediate circuit voltage, and
• In the event of the first upper limit value of the intermediate circuit voltage falling below the detected intermediate circuit voltage,
  • ◯ control of the reluctance motor by the drive circuit with the calculated conduction area, otherwise
• In the case of reaching or exceeding the first upper limit value or preferably of the second upper limit value of the intermediate circuit voltage by the detected intermediate circuit voltage,
  • ◯ reducing the calculated conduction area to an adapted conduction area as a function of the DC link voltage, and
  • ◯ Driving the reluctance motor by the drive circuit with the adapted guide area.

The present invention is based on the finding that a stable operation of a control of a reluctance motor when an angle error occurs, for whatever reason, may be achieved by reducing the effects of the angular error. In other words, according to the invention, the angular error itself and the reasons for its formation are not considered, but the angular error is accepted and the angle error or its effects on the control are improved.

In this case, the intermediate circuit voltage is considered as a measure of the effects of the angular error, as this can increase by an undesirable generator operation of the reluctance motor, which may result from an angle error, such that the drive circuit of the reluctance motor is destroyed.

According to the invention, this is taken into account by initially specifying at least one first upper limit value of the intermediate circuit voltage. If the DC link voltage is between 0V and the first upper limit in a common interval, it will go away assumed that there is no angle error or only such a small angle error that the resulting increase in the DC link voltage can be considered tolerable.

If, however, the first upper limit value of the intermediate circuit voltage is reached or exceeded, then the effects of the angular error on the intermediate circuit voltage are no longer considered tolerable. In this case, according to the invention, a further increase in the intermediate circuit voltage is thereby counteracted by reducing the conduction region which has hitherto been used. In this case, the term duration is to be understood as meaning the duration of time or the angle between the switch-on angle of the energization of a phase or a string of the reluctance motor and its turn-off angle.

Thus, in response to reaching or exceeding the first upper limit of the intermediate circuit voltage, the conduction area is reduced, and the time duration of the regenerative operation of the reluctance motor is reduced, which accordingly leads to a smaller increase in the intermediate circuit voltage due to a present angle error. Thus, the effects of the angular error can be easily and directly reduced.

When the first limit value is exceeded, according to the invention, the conduction region is reduced with increasing intermediate circuit voltage.

Preferably, a distinction is made between two upper limit values in order to be able to respond to the angle error as a function of the respectively reached or exceeded limit value of the intermediate circuit voltage. Thus, in the case of reaching or exceeding the first upper limit value can be checked by a further comparison, whether the second upper limit of the intermediate circuit voltage is exceeded. Depending on which of the two upper limit values is reached or exceeded, a different adjustment of the guide area can take place so that the extent of the angle error can be dealt with differently.

When the second limit value is exceeded, according to the invention, the conduction region is further reduced even more when the intermediate circuit voltage increases further than when the first limit value is exceeded.

In any case, depending on the reached or exceeded upper limit value of the intermediate circuit voltage, the conduction region can be reduced to different degrees, as will be explained in more detail below. In this case, the second upper limit value of the intermediate circuit voltage has priority over the first upper limit value of the intermediate circuit voltage, so that if both upper limit values are exceeded at the same time, the reduction of the calculated conduction area to an adapted conduction area as a function of the second upper limit value takes place, because these are preferably the can cause severe reduction.

According to one aspect of the present invention, in the case of reaching or exceeding the first upper limit value of the intermediate circuit voltage, the adapted conducting area is reduced in an anti-proportional manner to the calculated conducting area. In this way, can be done via a simple mathematical relationship, which can be correspondingly simple and reliable hardware and / or software side, a reduction of the guide area such that the reduction of the guide area is greater, the greater the angle error is, which would otherwise an inadmissibly high DC link voltage can lead. This can be a simple and reliable countermeasure for increasing angular error.

According to a further aspect of the present invention, the adapted conduction region is calculated as a function of the intermediate circuit voltage, for example as follows: $$\text{LB '}=\text{LB}\times \frac{\text{G1}}{\text{Ud}}$$

Expressed in words, the first upper limit of the intermediate circuit voltage is divided by the detected intermediate circuit voltage. Since this calculation is only carried out if the detected intermediate circuit voltage has already reached or exceeded the first upper limit value of the intermediate circuit voltage, this quotient is one when the first upper limit value of the intermediate circuit voltage is reached and less than one when the first upper limit value of the intermediate circuit voltage is exceeded. If this quotient is then multiplied by the calculated conduction range, the adapted conduction region can be at most equal to the calculated conduction region when the first upper limit value of the intermediate circuit voltage is reached and lies below the calculated conduction region when the first upper limit value of the intermediate circuit voltage is exceeded. As a result, the above-described reduction of the calculated guide range can be implemented simply and as directly as possible.

Generally speaking, in one embodiment, the adapted routing area is antiproportional to the DC link voltage. In this case also suitable offset and / or scaling values can be used. For example, in this example, the first limit G1 is used as the scaling value.

According to a further aspect of the present invention, in the case of reaching or exceeding the second upper limit value of the intermediate circuit voltage, the adapted conducting area is reduced, for example, exponentially to the calculated conducting area. In this way, it is possible to achieve a reduction in the conduction area and thus the effects of the angle error, which increases more than the angle error itself. In this way, a particularly effective reduction of the conduction region can be implemented in order to reduce the rise in the intermediate circuit voltage, which results from the excessively high and further increasing angle error, to a permissible level, so that damage or destruction of the actuation circuit can be prevented.

According to a further aspect of the present invention, the adapted conduction region as a function of the intermediate circuit voltage is therefore calculated, for example, as follows: $$\text{LB '}=\text{LB}\times {\left(\frac{\text{G2}}{\text{Ud}}\right)}^2$$

In this case, the quotient is squared and multiplied by the calculated guide area compared to the first upper limit value. This causes an increasing angle error and the resulting increase in DC link voltage to be quadratic, i. with the exponent two, affects the reduction of the conduction area, so that the conduction area is correspondingly reduced more than the angle error and the increase in the intermediate circuit voltage caused thereby can increase. This can effectively limit the increase of the DC link voltage.

Generally speaking, the adapted conduction region in this embodiment is antiproportional to a power> 1 (here 2) of the intermediate circuit voltage. In this case also suitable offset and / or scaling values can be used. In this example, for example, the second limit value G2 (with identical power> 1, here 2) is used as the scaling value.

According to another aspect of the present invention, the first upper limit value of the intermediate circuit voltage is less than the second upper limit value of the intermediate circuit voltage. In this way, first the first upper limit can be reached or exceeded before the second upper limit can be reached or exceeded. As a result, the first upper limit value can be used to initiate countermeasures against the increase in the intermediate circuit voltage, which is initially moderated, such as, for example, as shown in FIG. can be antiproportional. However, if these measures are not sufficient, the second upper limit can be used to initiate more effective ones, e.g. be used to exponentially reduce the conduction area to safely and effectively avoid a critical DC link voltage.

According to another aspect of the present invention, the method is performed in discrete time steps, wherein the detection of the intermediate circuit voltage in the previous time step of the method has taken place. In this way, on the one hand, a discrete-time control or regulation can be implemented, as is usual in digital technology. On the other hand, the detected intermediate circuit voltage of the preceding time step of the method can be used as a starting point, in order to respond to this, if necessary by reducing the conduction area in the current time step, as described above.

In accordance with another aspect of the present invention, the routing area is calculated based on an estimated angular position of the reluctance motor. In this way, e.g. For reasons of cost, a rotor position sensor is dispensed with as sensor and instead an estimated angular position is used. Especially in this case, the application of the measures described above to reduce the effects of an angle error on the DC link voltage may be advantageous because a sensorless control is usually less dynamic than a sensor-biased control and thus worse, or even disturbances that can lead to an angle error can not react sufficiently, so that a safe operation of the reluctance motor can be ensured. If, in this case, the guide area is reduced according to the invention as described above, so that reliable operation of the reluctance motor can be achieved despite angle errors, the sensorless control can compensate for the angular error even with less dynamics and lead the reluctance motor back into regulated operation without it had become uncertain in the meantime.

The present invention also relates to a reluctance drive having a reluctance motor, a drive circuit for driving the reluctance motor by means of a guide region, a control unit and a Leitbereichsadaptierungseinheit, wherein the drive circuit, the control unit and the Leitbereichsadaptierungseinheit are adapted to operate the reluctance motor together by a method as described above , In this way, the properties and advantages of the method described above can be implemented and used in a reluctance drive.

The present invention also relates to an electrical appliance, in particular an electrical domestic appliance, in particular an electric vacuum cleaner for domestic use, with at least one reluctance drive as described above for driving a component of the electrical appliance, in particular for driving an impeller of a blower of the electric vacuum cleaner. In this way, such a reluctance drive according to the invention can be used in an electrical device and in particular household appliance in order to implement and utilize its properties and advantages there. This can e.g. be in the household area a vacuum cleaner, a hand dryer, a kitchen appliance or the like, in which a reluctance can be used meaningfully.

In this case, the present invention can be usefully used in an electric vacuum cleaner, since there occur an angle error by a sudden interruption of the air flow by closing the suction port or by a sudden admission of the air flow by opening the suction port on the impeller of the fan and distracting can affect the operation of the reluctance motor. In addition, there may occur a state in which the air column oscillates in the hose of the vacuum cleaner, resulting in a swinging angle error can result. The effects of these disorders can be effectively reduced by the method according to the invention.

• 1 eine schematische Schnittdarstellung eines zweiphasigen Reluktanzmotors;
• 2 ein schematisches Schaltbild einer Ansteuerungsschaltung des Reluktanzmotors der 1;
• 3 eine schematische Darstellung eines bekannten Reluktanzantriebs;
• 4 eine schematische Darstellung eines erfindungsgemäßen Reluktanzantriebs;
• 5 ein Ablaufdiagramm eines erfindungsgemäßen Verfahrens zum Betrieb des Reluktanzmotors des erfindungsgemäßen Reluktanzantriebs;
• 6 den Verlauf der Zwischenkreisspannung (oben) und des ersten Phasenstroms (unten) des bekannten Reluktanzantriebs der 3; und
• 7 den Verlauf der Zwischenkreisspannung (oben) und des ersten Phasenstroms (unten) des erfindungsgemäßen Reluktanzantriebs der 4.

An embodiment of the invention is shown purely schematically in the drawings and will be described in more detail below. It shows

• 1 a schematic sectional view of a two-phase reluctance motor;
• 2 a schematic diagram of a drive circuit of the reluctance of the 1 ;
• 3 a schematic representation of a known reluctance drive;
• 4 a schematic representation of a reluctance drive according to the invention;
• 5 a flow diagram of a method according to the invention for operating the reluctance motor of the reluctance drive according to the invention;
• 6 the course of the intermediate circuit voltage (top) and the first phase current (bottom) of the known reluctance of the 3 ; and
• 7 the course of the intermediate circuit voltage (top) and the first phase current (bottom) of the reluctance drive of the invention 4 ,

1 shows a schematic sectional view of a two-phase reluctance motor 1 , The reluctance motor 1 has a fixed stator 10 on, inside which a rotor 15 is arranged rotatably about a rotation axis. The rotor 15 consists of a stamped laminated core of a ferromagnetic material such as iron.

The stator 10 consists of a ferromagnetic material such as iron and has four radially inward to the rotor 15 towards pointing projections, which the poles 11 . 13 of the stator 10 form. The poles 11 . 13 are each wrapped with electrically conductive wire such as copper, so that the windings 12 . 14 form. Here are the windings 12 . 14 the diametrically opposite poles 11 . 13 each connected in series and thus simultaneously flows through the same stream. The windings 12 the Pole 11 form the first strand or the first phase of the reluctance motor 1 and the windings 14 the Pole 13 the second strand of the reluctance motor 1 , The two phases are thus aligned orthogonal to each other. As soon as a phase is energized, ie energized, a magnetic field is created which is the rotor 15 moves into the respective phase position.

2 shows a schematic diagram of a drive circuit 2 of the reluctance motor 1 of the 1 , The drive circuit 2 is fed from an electrical supply network with an AC voltage as the mains voltage, which by a rectifier GL1 in a DC voltage Ud is converted. The rectified voltage Ud is above a capacitor C1 to which the DC link 20 the drive circuit 2 forms. The rectified voltage Ud can therefore also be used as DC link voltage Ud and the capacitor C1 as a DC link capacitor C1 be designated. The capacitor C1 is relatively small dimensions, so that the DC link voltage Ud can fluctuate very much, but the cost of the capacitor C1 can be kept comparatively low. This can be referred to as a "soft DC link" 20.

From the DC link 20 become the two phases of the reluctance motor 1 with the DC link voltage Ud fed. For this purpose, each phase of the reluctance motor 1 a so-called H-bridge 21 . 22 on. The first H-bridge 21 the first phase of the reluctance motor 1 has a first switchable power semiconductor T1 , a second switchable power semiconductor T2 , a first diode D1 and a second diode D2 on. Between the first switchable power semiconductor T1 and the first diode D1 on the one hand and the second switchable power semiconductor T2 and the second diode D2 on the other side are the windings 12 the first phase arranged in the presentation of the 2 through a coil L1 be represented. The second H-bridge 22 the second phase of the reluctance motor 1 has a third switchable power semiconductor T3 , a fourth switchable power semiconductor T4 , a third diode D3 and a fourth diode D4 on. Between the third switchable power semiconductor T3 and the third diode D3 on the one hand and the fourth switchable power semiconductor T4 and the fourth diode D4 on the other side are the windings 14 arranged in the second phase, which in the representation of 2 through a coil L2 be represented.

The two H-bridges 21 . 22 can the respective phase via the first or third switchable power semiconductor T1 . T3 as well as the first and third diode D1 . D3 from the DC link 20 out from one side and via the second and fourth switchable power semiconductors T2 . T4 as well as the second and fourth diode D2 . D4 from the DC link 20 energized from the other side. The current I1 the first phase, which is also the first phase current I1 , can be designated, for example flows over the second switchable power semiconductor T2 , The same applies to the electricity I2 the second phase, which is also called the second phase current I2 may be referred to with respect to the fourth switchable power semiconductor T4 ,

By means of the rectifier 2 can the connected reluctance motor 1 only be operated permanently in two-quadrant operation, ie the reluctance motor 1 can only be permanently operated by motor and not by generator. Therefore, no electrical energy from the DC link can 20 fed back into the electrical supply network.

The drive circuit 2 also has a control unit M1 in the form of a microcontroller M1 on which the H-bridges 21 . 22 controls and thus the operation of the reluctance motor 1 performs. Furthermore, the drive circuit 2 a measuring resistor R3 of the phase current I1 . I2 on, which between the second and fourth switchable power semiconductor T2 . T4 and the DC link 20 is arranged. That way, the microcontroller can M1 the DC link voltage Ud to capture.

Furthermore, the microcontroller M1 either the first or the second phase current I1 . I2 because the two phases are not energized at the same time, can be measured via the measuring resistor R3 the respective phase current I1 . I2 be recorded. Also, the microcontroller can M1 the energization of the two phases alternately over the two H-bridges 21 . 22 control by the microcontroller M1 the energization of a phase starts at a switch-on angle and ends at a switch-off angle; the period or the angular range between the switch-on angle and the switch-off angle can be referred to as a guide region.

3 shows a schematic representation of a known reluctance drive. This firstly has the reluctance motor already described above 1 of the 1 on which output side via its rotor 15 with a component to be driven 3 in the form of a load 3 such as the impeller 3 a blower of an electric vacuum cleaner is connected, so that the impeller 3 by means of the reluctance motor 1 can be driven rotationally. Furthermore, the reluctance drive of the 3 the drive circuit 2 of the 2 on.

The reluctance drive of 3 also has a control unit 4 on which of the reluctance motor 1 an angular position A of the rotor 15 opposite the stator 10 receives. The angular position A is sensory by a rotor position sensor (not shown) in the reluctance motor 1 detected. Based on this angular position A the control is performed by the control unit 4 such that the guidance area LB through the control unit 4 determined and the microcontroller M1 the drive circuit 2 is given.

The disadvantage here is the cost of the rotor position sensor, as already described above. However, if the rotor position sensor is dispensed with and sensorless control by means of an estimated angular position A 'is used, the encoderless control can be brought into unsafe operation due to its lack of dynamics due to an inadmissibly high increase in the intermediate circuit voltage Ud to destroy the drive circuit 2 can lead. These negative effects of a lack of dynamics of a sensorless control can be avoided according to the invention as follows.

4 shows a schematic representation of a reluctance drive according to the invention, the control unit 4 as already mentioned instead of a sensory detected angular position A of the reluctance motor 1 an estimated angular position A 'is supplied, which is used as the actual value of the control. In this case, according to the invention, the part of the control unit 4 certain guidance area LB not as before directly the drive circuit 2 or its microcontroller M1 but a Leitbereichsadaptierungseinheit 5 fed. The drive circuit 2 , the regulatory unit 4 and the routing area adaptation unit 5 together lead the following inventive method for operation of the reluctance motor 1 which is based on the flowchart of the 5 should be explained as follows:

In a first step 100 becomes the DC link voltage Ud the drive circuit 2 of the reluctance motor 1 detected in a discrete time step and made available for processing in the subsequent discrete time step.

In this subsequent discrete time step 200 is the part of the control unit 4 the guidance area LB for controlling the reluctance motor 1 by the drive circuit 2 calculated in the current discrete time step based on the estimated angular position A 'and the guidance area adaptation unit 5 fed.

In a third step 300 becomes the detected intermediate circuit voltage Ud the previous discrete time step from the Leitbereichsadaptierungseinheit 5 with a first upper limit value G1 of the intermediate circuit voltage Ud compared. The upper limit value G1 of the intermediate circuit voltage Ud can in the routing area adaptation unit 5 be firmly implemented or the Leitbereichsadaptierungseinheit 5 be provided from outside. This also applies to a second upper limit value G2 of the intermediate circuit voltage Ud which will be considered below.

• • im Falle, dass die erfasste Zwischenkreisspannung Ud des vorangegangenen diskreten Zeitschritts den ersten oberen Grenzwerts G1 der Zwischenkreisspannung Ud unterschreitet, kann davon ausgegangen werden, dass gar kein Winkelfehler vorliegt oder der Winkelfehler zumindest derart gering ist, dass es im vorangegangenen diskreten Zeitschritt durch den Winkelfehler zu keiner beachtenswerten Erhöhung der Zwischenkreisspannung Ud gekommen ist. Dementsprechend kann der Leitbereich LB wie von der Regelungseinheit 4 berechnet werden, um den Reluktanzmotor 1 anzusteuern, wie weiter unten beschrieben werden wird;
• • im Falle, dass die erfasste Zwischenkreisspannung Ud des vorangegangenen diskreten Zeitschritts den ersten oberen Grenzwerts G1 der Zwischenkreisspannung Ud erreicht oder überschritten hat, kann davon ausgegangen werden, dass ein derartig großer Winkelfehler vorliegt, dass es im vorangegangenen diskreten Zeitschritt durch den Winkelfehler zu einer beachtenswerten Erhöhung der Zwischenkreisspannung Ud gekommen ist. Dementsprechend wird erfindungsgemäß nun der von der Regelungseinheit 4 bestimmte Leitbereich LB in einem vierten Schritt 400 verringert, um eine weitere Erhöhung der Zwischenkreisspannung Ud zu reduzieren und hierdurch eine unzulässig große Erhöhung der Zwischenkreisspannung Ud zu vermeiden. Hierzu wird ein adaptierter Leitbereich LB' durch die Leitbereichsadaptierungseinheit 5 in Abhängigkeit der Zwischenkreisspannung und des ersten oberen Grenzwerts G1 wie folgt berechnet: $$\text{LB'}=\text{LB}\times \frac{\text{G1}}{\text{Ud}}$$
  
• • in Rahmen des dritten Schrittes 300 wird im letzteren Fall ferner überprüft, ob nicht nur der erste obere Grenzwert G1, sondern auch ein zweiter oberer Grenzwert G2 der Zwischenkreisspannung Ud, welcher größer als der erste obere Grenzwert G1 ist, erreicht oder überschritten ist. Ist dies der Fall, kann davon ausgegangen werden, dass bereits eine dramatisch große Erhöhung der Zwischenkreisspannung Ud eingetreten ist, welcher durch die Leitbereichsadaptierungseinheit 5 stärker als durch die zuvor beschriebene Formel in Abhängigkeit der Zwischenkreisspannung und des ersten oberen Grenzwerts G1 entgegengewirkt werden muss. Dies kann dann im vierten Schritt 400 durch die Leitbereichsadaptierungseinheit 5 stattdessen in Abhängigkeit der Zwischenkreisspannung und des zweiten oberen Grenzwerts G2 wie folgt erfolgen: $$\text{LB'}=\text{LB}\times {\left(\frac{\text{G2}}{\text{Ud}}\right)}^2$$
  

Depending on the third step 300 the comparison is now according to the invention as follows:

• • in the event that the detected intermediate circuit voltage Ud of the preceding discrete time step the first upper limit value G1 of the intermediate circuit voltage Ud can be assumed that there is no angle error at all or the angular error is at least so low that it in the previous discrete time step by the angular error to any notable increase in the DC link voltage Ud has come. Accordingly, the guidance area LB as from the control unit 4 calculated to be the reluctance motor 1 to drive, as will be described below;
• • in the event that the detected intermediate circuit voltage Ud of the preceding discrete time step the first upper limit value G1 of the intermediate circuit voltage Ud has reached or exceeded, it can be assumed that such a large angle error is present that it in the previous discrete time step by the angle error to a notable increase in the DC link voltage Ud has come. Accordingly, according to the invention now of the control unit 4 certain guidance area LB in a fourth step 400 decreases, to further increase the intermediate circuit voltage Ud to reduce and thereby an impermissibly large increase in the DC link voltage Ud to avoid. For this purpose, an adapted guidance area LB 'by the Leitbereichsadaptierungseinheit 5 calculated as a function of the intermediate circuit voltage and the first upper limit value G1 as follows: $$\text{LB '}=\text{LB}\times \frac{\text{G1}}{\text{Ud}}$$
  
• • in the third step 300 In the latter case, it is further checked whether not only the first upper limit value G1 but also a second upper limit value G2 of the intermediate circuit voltage Ud , which is greater than the first upper limit G1, is reached or exceeded. If this is the case, it can be assumed that already has a dramatically large increase in the DC link voltage Ud which passes through the Leitbereichsadaptierungseinheit 5 stronger than must be counteracted by the formula described above as a function of the DC link voltage and the first upper limit G1. This can then be done in the fourth step 400 through the routing area adaptation unit 5 instead, as follows, depending on the DC link voltage and the second upper limit G2: $$\text{LB '}=\text{LB}\times {\left(\frac{\text{G2}}{\text{Ud}}\right)}^2$$
  

In any case, after that, in a fifth step 500a . 500b for driving the reluctance motor 1 by the drive circuit 2 either the part of the control unit 4 calculated guidance area LB or by the routing area adaptation unit 5 reduced adapted conduction area LB 'used.

The effects of the method according to the invention on the stability of the control of the reluctance motor 1 show the 6 and 7 , where in the 6 the course of the DC link voltage Ud (above) and the first phase current I1 (bottom) of the known reluctance drive of 3 and in the 7 the course of the DC link voltage Ud (above) and the first phase current I1 (below) of the reluctance drive according to the invention 4 are shown.

In both representations of the 6 and 7 begins at time t = 0 seconds a vibration, which is a fault of the reluctance motor 1 represents. This vibration can be triggered in an electric vacuum cleaner, for example by the air column in the hose of the vacuum cleaner.

In the presentation of the 6 take both the DC link voltage Ud as well as the first phase current I1 very fast critical values, so the reluctance motor 1 must be switched off, to destroy the drive circuit 2 to avoid.

The presentation of the 7 shows the same situation using the reluctance drive of the invention 4 , In this case, although there is also a vibration which, via the resulting oscillating angle error, leads to an increase in the intermediate circuit voltage Ud beyond the usual range, so that at least the first upper limit value G1 of the intermediate circuit voltage Ud is exceeded. The reduction of the control unit according to the invention in this case 4 specific guidance area LB However, this leads to the effects of the angular error being able to be absorbed in such a way that critical values of the DC link voltage Ud can be avoided and the reluctance motor 1 can continue to operate.

LIST OF REFERENCE NUMBERS

A

sensory angular position

A '

estimated angular position

C1

Capacitor of the DC link

D1

first diode

D2

second diode

D3

third diode

D4

fourth diode

GL1

rectifier

I

electricity

I1

Electricity of the first phase; first phase current

I2

Current of the second phase; second phase current

LB

Control area according to regulation 4

LB '

adapted routing area according to routing area adaptation unit 5

L1

Coil of the windings of the first strand or the first phase

L2

Coil of the windings of the second strand or the second phase

M1

Control unit; microcontroller

network

mains voltage

R3

Measuring resistor of the phase current I1, I2

T1

first switchable power semiconductor

T2

second switchable power semiconductor

T3

third switchable power semiconductor

T4

fourth switchable power semiconductor

U

tension

Ud

Intermediate circuit voltage; DC voltage; rectified voltage

Time

Time

1

reluctance motor

10

stator

11

Pole of the first strand or the first phase

12

Windings of the first strand or the first phase

13

Pole of the second strand or the second phase

14

Windings of the second strand or the second phase

15

rotor

2

driving circuit

20

DC

21

first H-bridge of the first strand or the first phase

22

second H-bridge of the second strand or the second phase

3

component; Load; Impeller of a blower of a vacuum cleaner

4

control unit

5

Leitbereichsadaptierungseinheit

100

Detecting the DC link voltage Ud of the drive circuit. 2

200

Calculating a conduction region LB for driving the reluctance motor 1

300

Comparing the detected intermediate circuit voltage Ud with a first upper limit value G1 and optionally with a second upper limit value G2 of the intermediate circuit voltage Ud

400

Reducing the calculated conduction area LB to an adapted guidance area LB 'as a function of the respective limit value G1, G2

500a

Driving the reluctance motor 1 by the drive circuit 2 with the calculated guidance range LB

500b

Driving the reluctance motor 1 by the drive circuit 2 with the adapted conduction region LB '

Claims (10)

Method for operating a reluctance motor (1), comprising the steps: Detecting (100) the intermediate circuit voltage (Ud) of a drive circuit (2) of the reluctance motor (1), Calculating (200) a conduction region (LB) for driving the reluctance motor (1) by the actuation circuit (2), Comparing (300) the detected intermediate circuit voltage (Ud) with a first upper limit value (G1) of the intermediate circuit voltage (Ud) and preferably, in the case of reaching or exceeding the first upper limit value (G1), with a second upper limit value (G2) of the intermediate circuit voltage (Ud), and in the case of falling below the first upper limit value (G1) of the intermediate circuit voltage (Ud) by the detected intermediate circuit voltage (Ud), Driving (500a) of the reluctance motor (1) by the drive circuit (2) with the calculated conduction area (LB), otherwise in the case of reaching or exceeding the first upper limit value (G1) or preferably a second upper limit value (G2) of the intermediate circuit voltage (Ud) by the detected intermediate circuit voltage (Ud), Reducing (400) the calculated conduction region (LB) to an adapted conduction region (LB ') as a function of the intermediate circuit voltage (Ud), and Driving (500b) of the reluctance motor (1) by the drive circuit (2) with the adapted guide area (LB '). Method according to Claim 1 , characterized in that in the case of reaching or exceeding the first upper limit value (G1) of the intermediate circuit voltage (Ud), the adapted conducting area (LB ') is reduced in anti-proportional to the calculated conducting area (LB). Method according to Claim 2 , characterized in that the adapted guide region (LB ') is calculated as a function of the intermediate circuit voltage (Ud) as follows: $$\text{LB '}=\text{LB}\times \frac{\text{G1}}{\text{Ud}},$$

Method according to one of the preceding claims, characterized in that in the case of reaching or exceeding of the intermediate circuit voltage (Ud), the adapted conduction region (LB ') is reduced exponentially to the calculated conduction region (LB). Method according to Claim 4 , characterized in that the adapted guide region (LB ') is calculated as a function of the intermediate circuit voltage (Ud) as follows: $$\text{LB '}=\text{LB}\times {\left(\frac{\text{G2}}{\text{Ud}}\right)}^2,$$

Method according to one of the preceding claims, characterized in that the first upper limit value (G1) of the intermediate circuit voltage (Ud) is less than the second upper limit value (G2) of the intermediate circuit voltage (Ud). Method according to one of the preceding claims, characterized in that the method takes place in discrete time steps, wherein the detection (100) of the intermediate circuit voltage (Ud) is carried out in the previous time step of the method. Method according to one of the preceding claims, characterized in that the calculation (100) of the guide region (LB) is based on an estimated angular position (A ') of the reluctance motor (1). A reluctance drive comprising a reluctance motor (1), a drive circuit (2) for driving the reluctance motor (1) by means of a conduction region (LB; LB '), a control unit (4), and a conduction region adaptation unit (5), the actuation circuit (2) in that the control unit (4) and the guide area adaptation unit (5) are formed, the reluctance motor (1) together by means of a method according to one of Claims 1 to 8th to operate. Electrical device, in particular household electrical appliance, in particular electric vacuum cleaner for domestic use, with at least one reluctance drive according to Claim 9 for driving a component (3) of the electrical device, in particular for driving an impeller (3) of a blower of the electric vacuum cleaner.

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