DE102019118145A1 - Electrically commutated, multi-strand motor - Google Patents

Abstract

The electrically commutated, multi-strand motor (10) is provided with a stator (12) which has a plurality of winding sets, each with a plurality of windings (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ), each winding set per Each strand comprises at least one winding (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ). The motor (10) is also provided with a rotor (14) having poles (18), the stator (12) having teeth (16) and in each case at least one tooth (16) of a winding (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) and the plurality of winding sets are arranged geometrically uniformly offset by the windings assigned to the same strand (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) of the plurality Winding sets are each arranged geometrically evenly distributed over the stator (12). The motor (10) has a control unit (20) for the cyclical control of the windings (U ₁ , V ₁ , W ₁ ) and the windings (U ₂ , V ₂ , W ₂ ) depending on the respective rotational position of the rotor (14 ) on. Inactive windings are separated from the control.

Description

The invention relates to an electrically commutated motor, which is multi-strand or multi-phase. In particular, the invention relates to the use of the motor windings of the stator of an electrically commutated, multi-phase motor as redundancy.

In various applications, it is necessary not to completely lose the motor of a system as an actuator in the event of a fault. The system should therefore continue to be operable, even if this is done with a loss of performance. In this regard, it is a common procedure to provide the motor stator with a special, so-called redundant, winding. Here, two independent windings are drawn into the motor, since each winding exists twice, whereby each winding pair is intended for normal operation of the motor, while the second (redundant) winding is kept as a “reserve” for an error.

The electrical short circuit within a coil is one of the most common faults in electric motors. In such a case, permanent magnet synchronous motors induce a voltage in the windings by moving the rotor, which is short-circuited at the fault location. This creates high currents that brake the motor. In this case it is important to be able to separate the motor phases from the control electronics. The invention proposes the use of DE 10 2005 044 526 A1 and DE 10 2013 212 959 A1 together with the winding concept shown.

With regard to the state of the art, reference is also made to the further publications mentioned below: DE 10 2006 021 354 A1 . DE 10 2015 120 920 A1 . DE 31 40 034 A1 and STÖLTING, Hans-Dieter; KALLENBACH, Eberhard; Manual small electric drives. 2nd edition Munich: Hanser, 2002. p. 77, 81.-ISBN 3-446-21985.

The object of the invention is to propose an improved concept for using the motor windings of an electric motor stator for redundancy purposes. For this purpose, the winding system is divided into two levels of redundancy, whereby only one level is actively used at a time. The reserve is only used in the event of an error. The inactive level is completely separated from the motor at all times so that there is no reaction due to induced voltages.

• - einem Stator, der mehrere Wicklungssätze mit jeweils mehreren Wicklungen aufweist, wobei jeder Wicklungssatz pro Strang jeweils mindestens eine Wicklung umfasst,
• - einem Pole aufweisenden Rotor,
• - wobei der Stator Zähne aufweist und jeweils mindestens ein Zahn einer Wicklung zugeordnet sind und
• - wobei die mehreren Wicklungssätze geometrisch gleichmäßig versetzt angeordnet sind, indem die demselben Strang zugeordneten Wicklungen der mehreren Wicklungssätze jeweils geometrisch gleichmäßig über den Stator verteilt angeordnet sind, und
• - einer Ansteuereinheiten je Redundanzebene zur zyklischen Ansteuerung der Wicklungen in Abhängigkeit von der jeweiligen Drehposition des Rotors
• - wobei inaktive Redundanzebenen elektrisch vom Motor getrennt werden und dadurch keinerlei Einfluss auf das entwickelte Drehmoment (weder als Bremsmoment, noch als beschleunigendes Moment) haben.

To achieve this object, the invention proposes an electrically commutated, multi-strand, ie multi-phase motor, which is provided with

• a stator which has a plurality of winding sets, each with a plurality of windings, each winding set comprising at least one winding per strand,
• a rotor having poles,
• - The stator has teeth and at least one tooth is assigned to a winding and
• - The plurality of winding sets are arranged geometrically evenly offset, in that the windings associated with the same strand of the plurality of winding sets are each arranged geometrically evenly distributed over the stator, and
• - One control unit per redundancy level for cyclical control of the windings depending on the respective rotational position of the rotor
• - whereby inactive redundancy levels are electrically separated from the motor and therefore have no influence on the developed torque (neither as braking torque nor as accelerating torque).

• - „Strang“ ist bedeutungsgleich mit „Phase“ aufzufassen, bezeichnet also z.B. die drei Phasen U, V bzw. W
• - Drei dieser Phasen (Stränge) bilden gemeinsam einen „Wicklungssatz“
• - Jeder der in einem Wicklungssatz enthaltenen Stränge weist mindestens eine „ Wicklung“ im Sinne einer Spulenwicklung, beziehungsweise Spule auf.

To understand some of the terms used in connection with the invention:

• - “Strand” is to be understood with the same meaning as “phase”, for example it denotes the three phases U, V and W
• - Three of these phases (strands) together form a "winding set"
• - Each of the strands contained in a winding set has at least one “winding” in the sense of a coil winding or coil.

Analogously, the invention therefore proposes an electrically commutated, multi-strand motor with a plurality of winding sets, of which each winding set has as many windings as the motor has strands or phases (in the case of a three-phase motor, three windings per winding set). The windings for each winding set are each arranged on the stator in an evenly offset manner, and the plurality of winding sets are in turn evenly offset from one another in that the winding or windings of one winding set assigned to one strand is / are positioned between the strands associated with another winding set.

The invention therefore proposes to arrange the windings for each winding set offset by an identical first angular offset on the stator, and to arrange the winding sets one below the other to position a second angular offset different from the first angular offset in relation to one another. For the example of a three-phase motor with two winding sets, the three windings of each winding set are positioned offset from one another by 60 °, while the two winding sets are arranged offset from one another by 30 °, so that each winding of one winding set is arranged between two windings of the other winding set ,

The motor according to the invention has poles on its rotor and teeth on its stator. At least one tooth of the stator is assigned to a winding of another winding set.

The number of poles and teeth is selected as is known in the prior art when designing an electrically commutated, multi-phase motor. Therefore, this aspect will not be discussed further at this point.

According to the invention, the aspect of redundancy is solved by a geometric distribution of the windings of several winding sets. This feature shows the essential difference between the invention and the prior art, from which electrically commutated, multi-phase motors are known, in which the windings of redundant winding sets “lie one on top of the other”.

In an expedient development of the invention, it is provided that the windings of the plurality of winding sets belonging to the same strand can each be controlled jointly or separately, with inactive strands being electrically and possibly mechanically separated from the motor. The strands are mechanically separated, for example, by relays controlled by the control unit. A further possibility of separation is possible by blocking a semiconductor connection of the strands or windings with the control unit, as is the case, for example, in the two publications already mentioned above DE 10 2005 044 526 A1 and DE 10 2013 212 959 A1 is described.

The motor proposed according to the invention can alternatively operate in two different operating modes. If no winding is defective, the control unit can cyclically control all windings of all winding sets in order to operate the motor. In the event of a winding set failure, this means that the motor can still be operated afterwards, but with reduced performance. However, this is perfectly tolerable for a large number of applications.

The control unit controls the windings of only one of the winding sets. If an error occurs in this situation, the control unit switches to the control of the windings of another winding set and separates the previously active windings from the control. This scenario applies if there are two winding sets. It is also possible for a plurality of winding sets to be actuated in normal operation, in which case a plurality of redundancy winding sets are then advantageously also provided. In these cases, in which there are as many redundancy winding sets as there are controlled winding sets during normal operation of the motor, the motor does not lose power in the event of a fault.

Mixed forms of the two operating modes described above are also possible. For example, in the case of a motor with three winding sets, one of the winding sets could only be kept for redundancy purposes, so that if one of the two winding sets used in normal operation fails, this can be replaced by the redundancy winding set in order to provide the same motor performance again. as is the case in normal operation of the engine.

An alternative embodiment of the invention then consists in the control unit no longer controlling all the windings in the event of a defect in at least one winding and then at least one winding set.

The case of operating a motor with redundancy windings can then be described in that the control unit controls the windings of the plurality of winding sets with the exception of the winding of at least one of the winding sets, which thus functions as a redundancy winding set, and that the control unit in the event of a defect in at least one winding of the at least one controlled winding set whose all windings no longer control and instead controls the windings of the redundancy winding set or at least one of the redundancy winding sets (ie possibly controls the windings of at least one further redundancy winding set).

In a further expedient embodiment of the invention, it should be pointed out that it is possible for each strand in each winding set to be assigned at least one winding and thus at least one tooth of the stator, with several windings per strand being arranged next to one another and their teeth on the stator.

The invention is explained in more detail below with reference to the drawing. The following show in detail:

• 1a and 1b Schematic diagrams of a motor sheet metal section with 18 teeth and 10 pole pairs as an example, whereby the black current shows the energization of the individual windings U ₁ , V ₁ and W ₁ and U ₂ , V ₂ and W _{2 of} two winding sets, so that a three-phase system is created and this three-phase system in later operation for the magnetic rotating field of the motor, which pulls the rotor magnets, provides and according 1a all windings of both winding sets are energized, while according 1b only current flows through the windings of a winding set (redundancy),
• 2 the slot star for the configuration with 18 teeth and 10 pole pairs,
• 3 the geometrical addition of the induced voltages of individual slots to a three-phase system, in which three strands U, V, W are created, each with a 120 ° phase offset,
• 4 the winding diagram for the designed slot star and the three-phase system,
• 5 the electrical equivalent circuit diagram for the winding diagram derived from the slot star,
• 6 the winding scheme divided into the two redundancy systems and
• 7 the equivalent circuit diagram for the derived winding diagram according to 6 , divided into two levels of redundancy.

In the 1a and 1b the approach according to the invention is shown schematically. The electrically commutated, multi-strand, ie multi-phase motor 10 has a stator 12 and a rotor 14 on. The stator 12 is with a variety of teeth 16 provided while the rotor 14 a number of poles selected according to the number of teeth 18 having.

Several teeth each 16 of the stator 12 are each with the electrical conductor of a winding U ₁ . V ₁ . W ₁ respectively. U ₂ . V ₂ . W ₂ wrapped. Each tooth winding forms a coil, with several coils correspondingly forming a winding. In the exemplary embodiment there are two sets of windings U ₁ . V ₁ . W ₁ respectively. U ₂ . V ₂ . W ₂ , A control unit shown at 20 in the figures provides for the cyclical control of the various windings in a known manner, so that the windings generate a rotating magnetic field that the poles 18 of the rotor 14 "Pulls" and thus the rotor 14 set in rotation.

The present invention uses the concepts of so-called concentrated winding, in which each stator tooth is wound with a coil. If the motor now has a suitable coil group distribution and number (in the present example, the motor has 18 Teeth and 10 pole pairs), so the redundant winding as in the 1a and 1b will be realized. The indices 1 and 2 denote the windings of the three motor phases or motor strands U, V and W of two winding sets. The redundancy in this concept is achieved through the symmetry of the winding arrangements (winding sets). According to the invention, not every redundancy path encompasses every tooth of the motor. This is also not absolutely necessary to generate a uniform torque.

With this concept, a commercial brushless DC motor (BLDC motor) can be connected and operated as a motor with redundant windings.

The two levels of redundancy are each controlled by power electronics. If these two performance levels are synchronized in time, both levels of redundancy could work together (see in 1a , indicated by black representation of all windings of both winding sets). However, only one active level is intended to be used, while the second or third level only serves as a reserve. If a winding set fails, it is electrically disconnected so that it does not impair operation (see in 1b , indicated by the black representation of only the windings U ₁ . V ₁ and W ₁ ).

versetzt, wie in 2 gezeigt. Die Nutzahl entspricht N und die Polpaarzahl entspricht p, so dass sich in unserem Beispiel alle 200° ein Pfeil des Nutensterns ergibt.In order to be able to generate a three-phase system with the selected configuration of the stator windings, the individual coils of the windings, which are each formed around a tooth, must be suitably interconnected. For this purpose, a so-called slot star is often created during machine design. After the first slot has been freely numbered, the slots can be numbered clockwise or counterclockwise. Each additional groove lies around the angle $${\tau }_N=\frac{2\cdot \pi }{N}\cdot p$$

offset as in 2 shown. The usable number corresponds to N and the number of pole pairs corresponds to p, so that in our example there is an arrow of the slot star every 200 °.

The voltage induced in the conductors of the respective slot is to be assigned to a voltage space vector of the same spatial direction and number. The goal is now to connect the voltage pointers so that a symmetrical three-phase system with the greatest possible string voltages (arrow lengths) is formed. Suitable pointers must be added geometrically. 3 shows the associated slot voltage star for the present configuration with 18 slots and 10 pole pairs. In the picture is now to see that it is an interconnection in which parallel coil groups are created.

If you look at the representation of the 3 redrawn in a winding diagram, it becomes clear how the constellation according to 1 arose. In 4 the resulting winding diagram is drawn. It is now easier to see here that each phase is divided into two parallel coil groups.

Each winding encloses a tooth of the stator sheet and thus represents a coil with an iron core. Several such coils form a winding (phase). Can schematically 4 therefore also with an equivalent circuit diagram 5 being represented.

The in the 4 and 5 The parallel arrangement of the coil groups shown can now be resolved into two mutually independent (single redundancy) three-phase systems red1 and red2, as in 6 is shown.

An equivalent circuit diagram can also be created for this division into the two redundancy systems, as described in 7 is shown.

• - Weltraumanwendungen
• - Sicherheitskritische Anwendungen (wie z.B. Pumpen in Kühlkreisläufen)
• - Comfort Funktion in der Elektromobilität (das Auto bleibt im Fehlerfall nicht komplett liegen)

Fields of application of the invention are:

• - space applications
• - Safety-critical applications (such as pumps in cooling circuits)
• - Comfort function in electromobility (the car does not remain completely in the event of a fault)

LIST OF REFERENCE NUMBERS

10

engine

12

stator

14

rotor

16

teeth

18

Pole

20

control unit

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102005044526 A1 [0003, 0013]
• DE 102013212959 A1 [0003, 0013]
• DE 102006021354 A1 [0004]
• DE 102015120920 A1 [0004]
• DE 3140034 A1 [0004]

Claims (4)

Electrically commutated, multi-stranded motor, with - a stator (12), which has several winding sets, each with several windings (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ), each winding set per strand at least one Winding (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) comprises - a rotor (14) having poles (18), - wherein the stator (12) has teeth (16) and at least one Tooth (16) are assigned to a winding (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) and - the plurality of winding sets being arranged geometrically uniformly offset by the windings (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) of the several winding sets are each arranged geometrically uniformly distributed over the stator (12), and - a control unit (20) for the cyclical control of the windings (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) depending on the respective rotational position of the rotor (14), - with inactive redundancy levels electris ch be separated from the engine. Engine after Claim 1 , characterized in that the windings belonging to the same strand (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) of the plurality of winding sets can each be controlled separately. Engine after Claim 2 , characterized in that the control unit (20) in the event of a defect in at least one winding (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) of at least one winding set whose all windings (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) are no longer activated and electrically and / or mechanically disconnected. Engine according to one of the Claims 1 to 3 , characterized in that each strand in each winding set is assigned at least one winding (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) and thus at least one tooth (16) of the stator (12), with several windings (U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ ) per strand these and their teeth (16) on the stator (12) are arranged side by side.

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