阅读说明：本技术 用于操控电机的方法和用于车辆的驱动系统 (Method for controlling an electric machine and drive system for a vehicle ) 是由 J·文德 R·内勒斯 T·胡贝特 于 2020-09-15 设计创作，主要内容包括：本发明涉及一种用于操控电机(4)、尤其永久励磁的同步电机的方法,该电机具有：由第一逆变器(1)操控的、尤其三相的第一绕组系统；以及由第二逆变器(2)操控的、尤其三相的第二绕组系统,其中该第一逆变器(1)以块换相进行操作,并且该第二逆变器(2)以脉冲宽度调制、尤其空间矢量调制进行操作。(The invention relates to a method for controlling an electric machine (4), in particular a permanently excited synchronous machine, comprising: a first winding system, in particular three-phase, which is operated by a first inverter (1); and a second, in particular three-phase, winding system which is operated by a second inverter (2), wherein the first inverter (1) is operated with block commutation and the second inverter (2) is operated with pulse width modulation, in particular space vector modulation.)

1. Method for controlling an electric machine (4), in particular a permanently excited synchronous machine, having: a first winding system, in particular three-phase, which is operated by a first inverter (1); and a second, in particular three-phase, winding system which is operated by a second inverter (2), wherein the first inverter (1) is operated with block commutation and the second inverter (2) is operated with pulse width modulation, in particular space vector modulation.

2. Method according to claim 1, characterized in that the first and second winding systems are connected in parallel and the first inverter (1) and the second inverter (2) are operated in phase.

3. Method according to claim 1, characterized in that the first and second winding systems are connected anti-parallel and the first and second inverters (1, 2) are operated in anti-phase.

4. Method according to one of the preceding claims, characterized in that the clock frequency of the second inverter (2) is set in such a way that the sum of the switching losses of the first and second inverter (1, 2) is reduced, wherein undesired side effects, in particular noise, are preferably adjusted according to a defined criterion, in particular a weighting function.

5. Drive system, in particular traction drive system, for a vehicle (100), the drive system having:

an electric machine (4), in particular a permanently excited synchronous machine, comprising a first, in particular three-phase, winding system and a second, in particular three-phase, winding system,

-a first inverter (1) connected to the first winding system; and a second inverter (2) connected to the second winding system, and

-a control device (5) configured to operate the first inverter (1) with block commutation and the second inverter (2) with pulse width modulation, in particular space vector modulation.

6. Drive system according to claim 5, characterized in that the second inverter (2) has semiconductor switches with a higher maximum possible switching frequency than the first inverter (1).

7. Drive system according to claim 5 or 6, characterized in that a common intermediate circuit (3), in particular with a common intermediate circuit capacitor, is provided, which intermediate circuit is connected to the first inverter (1) and the second inverter (2).

8. Drive system according to one of claims 5 to 7, characterized in that the electrical machine (4) has a stator with a plurality of slots, wherein in each of the slots at least one first phase conductor of the first winding system and one second phase conductor of the second winding system are arranged.

9. A drive system according to claim 8, characterised in that a plurality of radial positions for arranging the phase conductors are provided in the slots, wherein the first phase conductor is arranged in a different radial position in the first slot than in the second slot, the first phase conductor preferably being arranged in all radial positions.

10. Vehicle, in particular electric vehicle or hybrid vehicle, having a drive system (10) according to one of claims 5 to 9.

Technical Field

The invention relates to a method for controlling an electric machine, in particular a permanently excited synchronous machine. The invention also relates to a drive system, in particular a traction drive system, for a vehicle.

Background

In a traction drive system for an electric or hybrid vehicle, a permanently excited synchronous machine is usually used as the electric machine. In order to operate such an electric machine, an inverter is usually provided, which supplies the electric machine with a multiphase operating voltage. The inverter typically operates with Space Vector Modulation (SVM). In this method of operating an inverter, a pulse-width-modulated operating voltage is supplied to the electric machine. There are some levels of switching and conduction losses in the power semiconductors. The inverter power supply carries, in addition to the basic oscillating voltage, also other high-frequency voltages. This results in significant losses in the stator (iron losses and electrical heat losses) and in the rotor (iron losses and magnet losses). Thereby possibly limiting the continuous power of the motor. In electric or hybrid vehicles, additional losses result in a reduction in range.

Disclosure of Invention

Against this background, it is proposed to increase the driving range of a vehicle driven by an electric motor.

In order to achieve this object, a method for controlling an electric machine is proposed, which electric machine has: a first winding system, in particular three-phase, which is operated by a first inverter; and a second, in particular three-phase, winding system which is operated by a second inverter, wherein the first inverter is operated with block commutation and the second inverter is operated with pulse width modulation, in particular space vector modulation.

In the method according to the invention, the first inverter is operated with block commutation, whereby switching losses can be reduced. Undesired harmonic oscillations in the magnetic flux, for example generated by the first inverter, can be compensated in an order-or frequency-based manner by the second inverter operating with pulse width modulation, in particular space vector modulation. Overall, therefore, an increase in the efficiency of the drive comprising the electric motor can be achieved, so that the driving range of a vehicle driven by the electric motor can be increased.

Preferably, the electric machine is designed as a permanently excited synchronous machine.

According to an advantageous embodiment of the invention, it is provided that the first winding system and the second winding system are connected in parallel, and that the first inverter and the second inverter are operated in phase. In this case, the same-phase operation is to be understood as an operation in which the windings of the first winding system and the windings of the second winding system are each operated in phase, wherein in particular the currents carried in these windings have the same current direction.

According to an alternative advantageous embodiment of the invention, it is provided that the first winding system and the second winding system are connected in anti-parallel, and that the first inverter and the second inverter are operated in anti-phase. In this case, an inverted operation is to be understood as an operation in which the windings of the first winding system and the windings of the second winding system are each operated in opposite phase, wherein in particular the currents carried in these windings have opposite current directions.

In an advantageous embodiment, the clock frequency of the second inverter is set in such a way that the sum of the switching losses of the first inverter and the second inverter is reduced, wherein undesired side effects, in particular noise, are preferably adjusted according to a defined criterion, in particular a weighting function. Alternatively or additionally, the clock frequency of the second inverter is set in such a way that harmonic oscillation losses are adjusted in an optimal way.

Another subject of the invention is a drive system, in particular a traction drive system, for a vehicle, having:

an electric machine, in particular a permanently excited synchronous machine, comprising a first, in particular three-phase, winding system and a second, in particular three-phase, winding system,

-a first inverter connected to the first winding system; and a second inverter connected to the second winding system, an

A control device configured to operate the first inverter with block commutation and the second inverter with pulse width modulation, in particular space vector modulation.

The same advantages as already described in connection with the method for operating an electric motor can be achieved in this drive system.

Preferably, the second inverter has semiconductor switches with a higher maximum possible switching frequency than the first inverter. Thus, in the first inverter, semiconductor switches having higher switching losses are used, and the material cost of the first inverter is reduced. Particularly preferably, the second inverter has SiC or GaN semiconductor switches, for example SiC MOSFETs or GaN FETs. The first inverter may have Si semiconductor switches, for example Si-IGBTs.

According to an advantageous embodiment, it is provided that the drive system has a shared intermediate circuit, in particular an intermediate circuit with shared intermediate circuit capacitors, which is connected to the first inverter and the second inverter. A compact and cost-effective configuration of the drive system can thereby be achieved.

In an advantageous embodiment of the invention, the electrical machine has a stator with a plurality of slots, wherein at least one first phase conductor of the first winding system and one second phase conductor of the second winding system are arranged in each of the slots.

In this connection, it is preferred that a plurality of radial positions for arranging the phase conductors are provided in the slots, wherein the first phase conductor is arranged in a different radial position in the first slot than in the second slot. Particularly preferably, the first phase conductors are arranged in all radial positions.

Another subject of the invention is a vehicle, in particular an electric vehicle or a hybrid vehicle, having a drive system as described above. The same advantages as already described in connection with the method and the drive system for operating an electric machine can be achieved in this vehicle.

Drawings

Further details and advantages of the invention should be elucidated by means of the embodiments shown in the drawings. Here:

fig. 1 shows a drive system according to a first embodiment of the invention in a schematic block diagram;

fig. 2 shows a motor of the drive system according to fig. 1 in a schematic sectional view;

fig. 3 shows a drive system according to a second embodiment of the invention in a schematic circuit diagram;

fig. 4 shows a drive system according to a third embodiment of the invention in a schematic circuit diagram;

fig. 5 shows an exemplary embodiment of a vehicle according to the invention in a schematic representation.

Detailed Description

Fig. 1 shows a drive system 10 designed as a traction drive for a vehicle, which has an electric machine 4 designed as a permanently excited synchronous machine. The motor 4 is fed by two separate, respective three-phase winding systems. In this regard, the electric machine 4 comprises a first winding system of three phases and a second winding system of three phases.

The first inverter 1 and the second inverter 2 are provided as further components of the drive system 10, which are operated by a control device 5 of the drive system 10. The first inverter 1 is connected to the first winding system and the second inverter 2 is connected to the second winding system. In order to reduce the switching losses of the inverter 1 and thus increase the driving range of a vehicle driven by the electric machine 4, the control device 5 is configured to operate the first inverter 1 with block commutation (blocking kommutizing) and the second inverter 2 with pulse width modulation, in particular space vector modulation.

The first inverter 1 has semiconductor switches whose maximum switching frequency is lower than the semiconductor switches of the second inverter 2. Therefore, significantly cheaper semiconductor switches can be used in the first inverter 1 than in the second inverter 2. For example, the semiconductor switches of the first inverter are designed as Si semiconductor switches and the semiconductor switches of the second inverter as SiC or GaN semiconductor switches.

In operating the drive system, the control unit operates the second inverter at a clock frequency such that the sum of the switching losses is minimized depending on the operating point and at the same time low-frequency harmonic oscillations in the magnetic flux generated by the first inverter are compensated. Here, the clock frequency of the second inverter 2 is variable according to the operating point characteristic curve.

The illustration in fig. 2 shows the electric motor 4 of the drive system 10 of fig. 1 according to a first embodiment. The electric machine 4 comprises a rotor 11 with permanent magnets comprising a north pole N and a south pole S. The electric machine 4 further comprises a stator 12 having a plurality, here exactly twelve slots 13. The slots 13 each have two radial positions in which the phase conductors of the winding system are arranged. The phase conductors are denoted with reference numerals a-F and a-F, wherein capital letters denote a first end of the phase conductor and lower case letters denote a second end of the phase conductor opposite the first end. The phase conductors a-C or a-C are the phase conductors of the first winding system and the phase conductors D-F or D-F are the phase conductors of the second winding system.

In the electrical machine 4 shown in fig. 2, the first phase conductor a or a is arranged in a different radial position in the first slot 13' than in the second slot 13 ″. Thus, the first phase conductor a or a is arranged in all radial positions provided by the slots of the stator 12. Furthermore, the remaining phase conductors B-F or B-F are arranged in the slots 13 in such a way that in each of the slots 13 at least one first phase conductor a-C or A-C of the first winding system and one second phase conductor D-F or D-F of the second winding system are arranged.

A second embodiment of the drive system 10 according to the invention is illustrated in a circuit diagram in fig. 3, in which the semiconductor switches of the first inverter 1 are illustrated next to the semiconductor switches of the second inverter 2. The semiconductor switches S 'of the first inverter 1 are shown by way of example in the circle K' next to the semiconductor switches S ″ of the second inverter 2. The phase conductors of the two winding systems are denoted by reference numerals a '-f'. In the drive system 10 according to fig. 3, the first winding system a ', b', c 'and the second winding system d', e ', f' are connected anti-parallel. The first inverter 1 and the second inverter 2 operate in reverse phase. The switches S' and S "have different switch states. The phase conductors a 'and d' of the two winding systems are thus actuated, for example, in opposite phases, so that the currents flow in the phase conductors a 'and d' in opposite current directions. The magnetic flux is generated in the same direction by the anti-parallel interconnection.

The two inverters 1, 2 are connected to a common intermediate circuit 3, in particular to a common intermediate circuit capacitor.

A third embodiment of a drive system 10 according to the invention is shown in a circuit diagram in fig. 4. The third drive system 10 according to the third embodiment substantially corresponds to the drive system of the second embodiment, wherein however the first and second winding systems a ', b', c ', d', e ', f' are connected in parallel and the first and second inverters 1, 2 are operated in phase. The switches S' and S "have the same switching state.

The illustration in fig. 5 shows a vehicle 100 with a drive system 10, which may be designed according to one of the embodiments described above. The vehicle 100 relates to an electric vehicle or a hybrid vehicle. The drive system 10 may be arranged in such a way that the wheels of the front axle or the wheels of the rear axle or the wheels of the front axle and the rear axle can be driven with the drive system. Alternatively, it is also possible to drive exactly one wheel with the drive system.

According to a variant of the above embodiment, the number of pole pairs of the electric machine 4 can be greater than 1, wherein the rotor comprises in particular a plurality of south poles S and north poles N. For example, a plurality of permanent magnets may be arranged on the rotor.

Another variant of the above embodiment provides that the number of pole pairs is 1, the rotor 11 comprises six slots, and the number of holes is 1, wherein the number of holes indicates the number of slots per pole and branch.

Another variant proposes that the number of pole pairs is 1 and that the rotor 11 comprises twelve slots.