WO2018121906A1

WO2018121906A1 - Electric machine with synchronous generation of pulse patterns

Info

Publication number: WO2018121906A1
Application number: PCT/EP2017/078029
Authority: WO
Inventors: Sebastian Strache; Thomas Koss
Original assignee: Robert Bosch Gmbh
Priority date: 2016-12-28
Filing date: 2017-11-02
Publication date: 2018-07-05
Also published as: CN110089024A; CN110089024B; DE102016226256A1

Abstract

The invention relates to an electric machine with a stator and a rotor. The stator has a plurality of stator coils. The electric machine also has at least two power output stages, each of which is connected to some of the stator coils on the output side. According to the invention, the electric machine has a master unit, said master unit being designed to generate a master synchronization signal in order to actuate the stator coils in a temporally synchronized manner. The electric machine has at least two slave units, each of which has a pulse pattern generator and a power output stage that is connected to the pulse pattern generator on the input side. The slave unit is designed to generate a pulse pattern signal for rotating the rotor on the basis of the master synchronization signal. Each of the slave units is designed to generate a slave clock signal in order to generate the pulse pattern signal, to detect, in particular to scan, the master synchronization signal using the slave clock signal, and to generate the pulse pattern signal on the basis of the master synchronization signal in a synchronized manner such that a pulse pattern clock represented by the pulse pattern signal is determined by the master synchronization signal.

Description

description

title

Electric machine with synchronous pulse pattern generation

State of the art

The invention relates to an electrical machine with a stator and a rotor. The stator has a plurality of stator coils. The electric

Machine also has at least two power output stages, which are each connected on the output side with a part of the stator coils.

Disclosure of the invention

According to the invention, the electric machine has at least or only one

Master unit, wherein the master unit is formed, a

Master synchronization signal, hereinafter also referred to as master sync signal to generate for timely control of the stator coils. The

The electric machine has at least two slave units which each have a pulse pattern generator and an input side with the pulse pattern generator.

Generator connected power amplifier has. The slave unit is formed, depending on the master sync signal, and in particular a master PWM command signal generated by the master unit, a pulse pattern signal, in particular PWM signal (PWM = Pulse Width Modulation) for

Rotate the rotor to produce. The slave units are each designed to generate a - in particular constant or invariable - slave clock signal for generating the pulse pattern signal, and

Mastersyncsignal by means of the slave clock signal to detect, in particular to sample, and to generate the pulse pattern signal in response to the master sync signal at the same time that a through the pulse pattern signal

represented pulse pattern clock - in particular only - is determined by the master sync signal. Advantageously, the simultaneous generation of the pulse pattern signal regardless of a frequency deviation of the slave clock signals with each other.

The master sync signal preferably has a time sequence of, in particular, rising and / or falling edges. More preferably, the

Master sync signal temporally - in particular periodically or non-periodically - successive pulses and pulse pauses, with a pulse followed by a pulse pause. The pulse has a pulse duration and the pulse pause has a pulse pause duration. A pulse and a pulse break together form a pulse period with a pulse period duration. Preferably, the pulse has a rising edge and a falling edge. For example, the pulse is formed by a rectangular pulse, a sawtooth pulse or a triangular pulse.

As a result, the slave units can advantageously time-synchronously with one another, in particular in accordance with the master sync signal

generate successive PWM single pulses and thus simultaneously drive the rotor to rotate. Advantageously, so at an electrical

Machine be formed a redundant pulse width modulated control of the stator, wherein the redundant control by at least two or a plurality of mutually independent pulse pattern generators in the slave

Units can be made. Each slave unit is at least one

Statorspule or a plurality of stator coils associated with the stator.

For example, a three-phase electric machine may have its own pulse pattern generator for each phase. The pulse pattern generations in the thus formed, three independently operating pulse pattern generators in three slave units can work synchronously to each other by the temporally parallel sampling of the master sync signal by the slave units, even if the timing of the slave units, for example conditionally by different temperatures, or component tolerances, are different from each other, and differ from each other. Advantageously, in the aforementioned electrical machine, a quartz oscillator of a timer of a slave unit generate a time signal whose frequency of a

Time signal of the timer of another slave unit - for example due to component tolerances or mutually different temperatures

electronic components - deviates since the frequency deviation of the slave Unit so has no influence on PWM generation. The slave clock, represented by the slave clock signal, can thus - apart from the mentioned temperature drift or component change - remain unchanged, and so does not need to be electronically adjusted or tracked.

Advantageously, a clock signal of a timer of the slave unit needs not be changed and can with its by component tolerance or

Temperature change caused frequency detuning to the other slave units or with respect to the master sync signal, continue to swing. A temporal conformity of the PWM signals of the slave units is thus effected by an adaptation of the pulse duration of the PWM individual pulse generated by the PWM generator of the slave unit. For example, a PWM single pulse of a faster oscillating slave unit may be generated by means of more slave clock periods or clock oscillations than a PWM single pulse from a slower oscillating further slave unit in comparison. Advantageously, the timely control of the slave units causes an increase in efficiency in the generation of torque and a reduction of the noise caused by the machine.

The master unit preferably has a processing unit, in particular a computer processor, for example a microprocessor or a microprocessor

Microcontroller, up. The master unit is preferably formed, the

Generate master sync signal, which represents a default timing for generating the PWM signal, in particular a PWM clock, and to send this to the slave unit.

The master unit, in particular the processing unit, is preferably designed for each slave unit - in particular for the respective one

Slave unit individually generated - Master PWM command signal to be generated, which represents a pulse width, in particular pulse duration, to be generated by the slave unit PWM pulse and to send this to the slave unit. The master unit can thus generate mutually different master PWM command signals for the slave units and thus specify a desired rotational movement of the rotor. Preferably, the slave unit has an input for the master PWM command signal and is at least indirectly connected to the master unit and configured to generate the PWM signal in response to the master PWM command signal.

In a preferred embodiment, the machine has a data bus, wherein the master unit is connected to the slave units by means of the data bus and configured to send the master PWM default signal to the slave unit via the data bus.

Preferably, the master PWM command signal represents a pulse pattern of the PWM signal to be generated by the slave unit. The master PWM

The default signal thus indirectly represents a torque to be generated by the rotor and / or a rotor speed.

In a preferred embodiment, the slave unit has an input for the master sync signal. The slave unit preferably has one

Processing unit, in particular a computing unit, which is adapted to determine a number of clock pulses or clock oscillations of the slave clock signal, which corresponds to the represented by the master sync signal temporal edge or pulse spacing of successive edges or pulses, and the pulse pattern periods, in particular one Pulse train clock frequency successive PWM single pulses to generate according to the determined number of clock pulses of the slave clock signal.

Preferably, the slave unit is designed to generate a PWM period data set representing the number of clock pulses and this

save. The PWM period data set preferably represents the number of oscillations of the slave clock corresponding to a predetermined number of pulse pattern periods. Preferably, the slave unit may generate a predetermined number of pulse pattern periods depending on the generated data set. The slave unit can thus - preferably continuously - or at predetermined time intervals, scan the master sync signal and thus a possible temperature drift or frequency change of their own

Clock signal for generating the pulse pattern signal by means of a - in particular continuous adaptation to the master sync signal, in particular the temporal edge spacing of consecutive edges or pulses,

compensate and so prevent a deviation of the PWM clock.

In a preferred embodiment, the master unit is configured to generate a period number signal which is a number during a

Pulse repetition period or pulse period of the master sync signal to be generated pulse pattern periods represents. The slave unit preferably has an input for the period number signal, and is designed to have a clock duration, in particular a number of the clock pulses of the slave clock signal

Pulse pattern period corresponds to determine depending on the period number signal. By means of the period number signal, which can be sent from the master unit to the slave unit, so a number of pulse pattern periods, which between two successive clock pulses of the

Master sync signal from the slave units to each other to be generated synchronously, are set by the master unit dynamically. The

Period number signal can be sent, for example via a data bus together with the PWM command signal to the slave units.

Other than described above, the number of pulse pattern periods to be generated by the slave units corresponding to the time pulse interval or the pulse clock of the master sync signal may be predetermined for the electric machine, and thus for the master unit and the slave units , Thus, the slave unit may advantageously generate the pulse pattern signal for a pulse pattern period corresponding to the master sync signal.

In a preferred embodiment, the slave unit has a

Computing unit, which is formed, a clock pulses representing division remainder from its determination of the clock duration of the pulse pattern period to a clock period of at least indirectly successive subsequent pulse pattern periods or pulse pattern half periods - in particular depending on

Master sync signal - to add up, and so to produce a pulse pattern period with extended cycle time. In this way, an error, in particular a frequency deviation in the pulse pattern generation in the Slave units, based on a resynchronization of the pulse pattern generators, are minimized.

In a preferred embodiment, the arithmetic unit of the slave unit is formed on chronologically successive pulse pattern periods or

Pulse pattern half periods each add a clock pulse until the

Divisional remainder is consumed. So the remainder of the division can be advantageous

low cost - for example, by means of an iterative binary algorithm - be distributed to successive pulse pattern periods.

In a preferred embodiment, the arithmetic unit is configured to add one clock pulse to temporally successive pulse pattern periods or pulse pattern half periods omitting at least one pulse pattern period until the remainder of the division has been consumed. The remainder of the division

preferably represents an integer number of clock pulses. In this way, a synchronization variation of the electric machine can be designed to be particularly low, as far as a cycle time change of the individual pulse pattern periods is evenly distributed over a PWM pattern generated by the slave units, represented by the PWM signal.

Preferably, the arithmetic unit is formed, every second or every third

To omit the pulse pattern period, so that a sequence is formed with addition gaps of successive pulse pattern periods. This allows a uniform distribution of the represented by the remainder of the division

remaining pulse pattern pulses are formed in the PWM signal.

In a preferred embodiment, the electric machine has a slave unit for each phase of the machine. Advantageously, the electric machine can be so unlike an electric machine with only one pulse pattern generator and, for example, a B6 bridge, which is formed, the

Stator coils of a stator to energize - mutually redundant

Emergency running properties formed by the autonomous pulse pattern generation of the slave units have. In a preferred embodiment, the electric machine has at least two sub-machines, each having the same number of phases, wherein the machine for each sub-machine, more preferably for each phase of the sub-machine - has at least one slave unit. To this

Way, the electric machine can be operated with certainty in case of failure of part of a sub-machine or a complete failure of a sub-machine with the rest of the sub-machine or in the case of several sub-machines with the other sub-machines still safe.

In a preferred embodiment, a clock frequency of the slave clock is a multiple of the edge or pulse repetition frequency of

Mastersyncsignals. For example, a clock frequency of the slave clock is more than ten megahertz, for example, 33 megahertz. An edge or pulse repetition frequency, for example, of the master sync signal is less than

100 kilohertz, for example 20 kilohertz.

In a preferred embodiment, the master unit is formed, a period duration, preferably a repetition frequency of the master sync signal, and thus in particular a time interval of the pulses, the pulse duration of the pulses and / or the length of the pulse pauses between directly in time

consecutive edges or pulses. With a modulation of the pulse duration of the pulses, a pulse pause between two consecutive pulses can remain constant. For this purpose, the master sync signal can be modulated, for example by a modulator of the master unit, in particular pulse width modulator. Advantageously, such a PWM frequency of the PWM signal generated by the slave unit from the master unit via the

Master sync signal are controlled. The slave units generate a predetermined number of PWM periods between two consecutive edges or pulses, or a number of times corresponding to the period number signal

PWM periods. As a result, advantageously, a frequency bandwidth of the PWM generation can be changed by the master synchronization signal and thus influenced. For example, an increase or decrease in the period of the pulse sequence of the master sync signal causes a change in the PWM frequency content, in particular a spectral power density, what advantageously causes a change in a noise emission of electromagnetic waves.

Preferably, the master unit is formed, the repetition frequency, in particular a time interval of the pulses or the length of the pulse pauses between temporally immediately successive edges or pulses of

Mastersyncsignals at random, in particular in response to a generated random number to change. Preferably, the master unit or one with the

Master unit connected processing unit, in particular microprocessor or microcontroller, designed, the repetition frequency with a

Random frequency value to generate randomly within a predetermined frequency interval, so that a frequency bandwidth of the PWM signals generated by the slaves is increased. As the frequency bandwidth is increased, the energy of the PWM pulses is distributed within a frequency spectrum, which has a positive effect on EMC (electro-magnetic compatibility) emission behavior.

For this purpose, the master unit can have a modulator which is designed to have a pulse repetition frequency of the master sync signal in such a way-preferably by means of a change or fluctuation of the period modulated onto the period duration

Period of the pulse sequence - to modulate that a frequency content of the

PWM signal - especially in comparison without modulation - is increased. Preferably, the modulator is formed, a frequency band or

To increase the frequency interval of the PWM generation. Preferably, the

Modulator configured to generate the modulation such that the PWM signal white noise, in particular band noise of a predetermined

Frequency bandwidth is superimposed. In another embodiment, the modulator is designed to carry out the modulation by means of chirp modulation, sine modulation, frequency hopping or dithering within a predetermined modulation bandwidth of the pulse repetition frequency.

The invention also relates to an electric drive for an electric vehicle or a hybrid vehicle having an electric machine of the type described above, wherein the machine is designed to have a torque for moving the vehicle

Produce vehicle. The invention also relates to a power steering system for a vehicle with an electric machine of the type described above, wherein the machine is configured to generate a supporting steering torque for vehicle steering.

The invention also relates to a method for operating an electrical machine.

In the method, at least two parts of the stator coils of the machine each form a submachine.

The submachine is driven by a slave unit connected to the submachine, wherein a drive pattern for energizing the submachine is generated by the slave unit.

A time synchronization of the slave units with each other is predetermined by a master sync signal, which comprises a time interval comprising a

Start time and an end time for a predetermined number - or from the

Master unit separately by means of a period number signal transmitted number - represented by the slave units PWM periods to be generated.

The slave units each have a timer which generates a slave clock signal representing a clock cycle for the slave unit independently of the master, in particular of a timer of the master, wherein the

Slave clock signal represents a clock cycle with which the slave unit, in particular a microprocessor or microcontroller of the slave unit is clocked. Preferably, the slave clock signal remains unchanged. The master sync signal is sampled by the slave unit at the timing of the slave clock signal of the slave unit, and a number of clock pulses or clock oscillations of the slave unit

Slave clock signal determines which of the master sync signal

represented time sequence particularly rising or falling edges corresponds. Preferably, a number of clock pulses or clock oscillations of the slave clock signal is determined by the slave unit, which one

Period between successive edges, for example, rising or falling edges or pulses corresponds. Further, from the slave unit, in particular the PWM generator of the slave unit, the pulse pattern periods for a rotor revolution corresponding to the number of clock pulses generated. A pulse period with the aforementioned period duration preferably has a pulse pause and a pulse.

The invention will now be described below with reference to figures and others

Embodiments described. Further advantageous embodiments will become apparent from the features described in the figures and in the dependent claims.

FIG. 1 shows an exemplary embodiment of an electrical machine which has a master unit and two slave units, wherein the slave units are respectively designed to scan a pulse sequence generated by the master unit as a master sync signal and to determine a number of slave clocks corresponding to the master sync signal, and thus a chronological one To create synchronization with each other;

Figure 2 shows schematically an embodiment of a method according to which the slave units of the electric machine shown in Figure 1 can be synchronized with each other;

FIG. 3 schematically shows a chronological sequence of pulse pattern periods, among which a remainder of the division comprising individual slave clocks

successive pulse pattern periods is distributed with the addition of individual pulse pattern clocks, so that the individual pulse pattern periods are each formed longer in time than pulse pattern periods to which no slave clocks are added;

FIG. 4 schematically shows a chronological sequence of pulse pattern periods, under which a remainder of the division comprises individual slave clocks

successive pulse pattern periods are distributed with omission of individual pulse pattern periods; Figure 5 shows a control unit for an electric machine, wherein the

Control unit comprises a master unit and a plurality of slave units, which are connected via a data bus to the master unit.

FIG. 1 shows an exemplary embodiment of an electrical machine 1. The stator 1 has in this embodiment six stator coils, namely a stator coil 4, a stator coil 5 and a stator coil 6, which together form a dividing machine 10. Three more stator coils of the six stator coils, namely one

Stator coil 7, a stator coil 8 and a stator coil 9, together form another sub-machine 1 1. The stator 2 thus has two sub-machines. The stator coils of the sub-machines are in this embodiment in

Star connection connected together. The stator coils of the sub-machines can - unlike shown in Figure 1 - be connected to each other in delta connection. The stator coils 4, 5, 6, 7, 8 and 9 are in this

Embodiment shown schematically within the stator 2. For example, a physical arrangement of the stator coils on the stator can include a circumferential angle of 120 degrees between two adjacent stator coils of the same submachine for each submachine.

The electric machine 1 also has a power output stage 12, which is connected on the output side via an output terminal 28 to the stator coils 4, 5 and 6 of the dividing machine 10 and which is formed, the stator coils 4, 5 and 6 of the dividing machine 10 for generating a rotating magnetic field to energize. The electric machine 1 also has a power output stage 13, which on the output side via an output terminal 29 with the

Statorspulen 7, 8 and 9 of the dividing machine 1 1 is connected.

The electric machine 1, for example, also has one

Rotor position sensor 14 which, for example, by a Hall sensor, a GMR sensor (GMR = Giant Magneto-Resistive) or an AMR sensor (AMR = Anisotropic Magneto-Resistive) is formed. The rotor position sensor 14 is configured to detect a rotor position of the rotor 3 and a

Rotor position signal representing rotor position to produce. The electric machine 1 also has a slave unit 15, which the Power output stage 12 includes and a slave unit 16, which the

Power output stage 13 includes. The electric machine 1 also has a master unit 17, which is designed to generate a master PWM specification signal and a master sync signal for driving the slave units 15 and 16, in dependence on which the slave units 15 and 16 indirectly each have a pulse pattern -Signal for driving the power amplifier 12 and 13 can generate. For example, the master PWM command signal represents at least one PWM pattern to be generated, and thus represents a duty cycle of the PWM drive. A torque to be generated or additionally a rotor speed or a direction of rotation of the rotor can thus be specified by the master unit.

The master unit 17 is connected on the input side to the rotor position sensor 14 and can thus generate the master PWM specification signal as a function of the rotor position signal. The master unit 17 is connected on the output side via a connection 31, for example a data bus, to the slave units 15 and 16 and designed, the master PWM specification signal, for generating the PWM signals by the slave units 15 and 16 to the slave - Send units 15 and 16.

The connection 31 may be formed differently than previously described, for example, as an electrical connection line.

In this exemplary embodiment, the master unit 17 has a timer 23, in particular a quartz oscillator, which is designed to generate a time signal and to output it. The master unit 17 also has a

Processing unit 20, in particular microprocessor or microcontroller, which on the input side connected to the timer 23 and is adapted to generate depending on the time signal, the master sync signal or additionally the master PWM command signal.

For example, the master PWM command signal may include a torque, a start time for starting a rotational movement of the rotor, a rotational angle of the rotor, or a torque output via the rotor should, or additionally represent the aforementioned period number signal. The slave unit 15 has an input 26 for the master sync signal 30.

The master unit 17 is connected on the output side to the input 26 of the slave unit 15 and designed to send the master sync signal 30 via the input 26 to the slave unit 15. The slave unit 16 has an input 27 for the master sync signal 30. The master unit 17 is also connected on the output side to the input 27 of the slave unit 16 and formed, the

Master sync signal 30 to send the slave unit 16 ..

The connection between the master unit 17 and the slave units 15 and 16 is formed for example by a data bus, in particular an SPI data bus. The master sync signal or, in addition, the master PWM command signal can thus advantageously be transmitted via the data bus to the slave units. For example, a common synchronization of the slave units with each other over only one electrical connection - for example, formed by an output terminal of the master unit for the

Master sync signal - done. For example, unlike previously described, the connection is a point-to-point connection in which the master unit is connected to the slave units via separate connection lines.

The slave units 15 and 16 can each sample the master sync signal 30.

For this purpose, the slave unit 15 has a timer 25, which is designed to generate a slave clock signal 34 and to send this to a processing unit 21. The processing unit 21 is formed in this embodiment, to sample the master sync signal 30 and to determine a number of slave clock pulses or slave clock periods of the slave clock signal, which correspond to a period, in particular the time pulse sequence of the master sync signal. The processing unit 21 is designed to generate a corresponding data record which determines the pulse pause duration, in the case of

periodic master sync signal of the cycle time or period of the

Master sync signal represents.

The slave unit 15 also has a in this embodiment

Pulse width modulator 18, which is the input side to the processing unit 21 and the output side connected to the power output stage 12 and is designed to generate a pulse pattern signal 36 and send this output side to the power output stage 12. The pulse width modulator 18 may generate the pulse pattern signal 36 as a function of the data set generated by the processing unit 21, which represents the period of the pulse sequence of the master sync signal. In addition, the pulse width modulator 18 can generate the pulse pattern signal 36 as a function of the master PWM command signal received via the connection line 31, wherein the number of pulse pattern periods to be generated for a pulse period of the master sync signal is determined by the pulse width modulator 18 - for example by a stored number in FIG Pulse width modulator - is determined. The slave unit

16 has a pulse width modulator 18 corresponding

Pulse width modulator 19, which is designed to generate a pulse pattern signal 37 and send this output side to the power output stage 13 for the corresponding powering of the sub-machine 1 1.

The pulse width modulator 19 is connected on the input side to a processing unit 22 which is connected on the input side to a timer 24 and is adapted to sample the master sync signal 30 received at the input 27 as a function of a slave clock signal 35 generated by the timer 24 Slave unit 15 described - the

Pulse width modulator 19 for time-synchronous generation of the pulse pattern signal 37 to control.

The processing units 21 and 22 are each configured to receive a synchronization signal generated by the master unit for starting the synchronous PWM period generation, so that all slave units can perform a PWM signal generation in synchronism with one another. The slave units are designed, for example, a resynchronization of the PWM generation after each reception of a new one

Mastersynchronisationspulses or - in response to a predetermined number of received successive pulses of the master sync signal, for example, less than five, as ten or as a hundred pulses - perform.

The pulse width modulators 18 and 19 can thus generate the pulse pattern signals 36 and 37 in synchronism with one another, even if the slave clock signals 35 and 34 deviate from one another, that is to say different frequencies, for example, due to component tolerances or mutually different temperatures.

The sub-machines 10 and 1 1 can thus be controlled in time-synchronous manner as a function of the master sync signal 30 without having to change a timing of the slave clock signals 34 or 35 or the slave clock signals 34 or 35 by means of a PLL (PLL) method. Locked loop) are approximated to the master sync signal 30.

FIG. 2 shows an exemplary embodiment of a method for generating the pulse pattern signal 36 or 37 already shown in FIG. 1 as a function of the master sync signal 30. The master sync signal 30 has a pulse repetition period 33, in particular period duration, which in this exemplary embodiment is 400 microseconds and eight generating pulse pattern periods of the pulse pattern clock corresponds.

In a method step 40, the master sync signal 30 is converted by means of a comparator and sampled at a clock frequency which corresponds to the slave clock 34. The slave clock 34 is generated by the timer 25 for this purpose. The comparator is designed to detect a pulse, in particular a steep edge of a pulse of the master sync signal, and to generate an output signal which represents the pulse, in particular pulse start.

In a step 41, a data record is generated in particular as a function of the output signal of the comparator, which represents the number of clock pulses or clock oscillations of the slave clock signal 34, which the

Pulse train duration 33 or pulse period duration of the master sync signal 30

correspond. The slave clock frequency is, for example, 38.65 megahertz. The number of clock pulses of the data set thus generated is then

for example, 15,460 clock pulses.

In a further step 43, a period duration of a pulse pattern period is calculated. For this purpose, the number of pulse pattern periods can either be predetermined be, for example, stored in a memory of the slave unit, or as already shown in Figure 1, from the master unit as

Period number signal to be sent to the slave unit, the

Period signal, the number of pulse pattern periods to be generated based on a temporal pulse interval or a pulse period of the

Master sync signal represents.

In a step 42, a pulse pattern period duration data set corresponding to the division result generated in step 43 is generated from the division result generated in step 43. In a further step 44, a remainder of the remainder is determined, and in a step 45 a remainder data set representing the integer remainder of the remainder is generated.

In a step 46, a pulse pattern period is generated and the

Pulse pattern periodic data record 42 loaded and the remaining data set loaded.

In a further step 47-for example by means of a discriminator of the slave unit, which is contained for example by the processing unit 21-the number of clocks of the residual data set is detected. If the number of clocks of the remaining data set is more than zero, then in a further step 48 the number of clocks of the remaining data set is reduced by an integer value and in a further step 49 a pulse pattern period with a period duration is generated which corresponds to the number of clocks of the clock cycle Pulse pattern period duration data set and additionally a periodic clock of the slave clock, generated by the timer of the slave unit corresponds.

If, in step 47, the value of the remaining interval is equal to zero, then in a step 51 a pulse pattern period with the period duration of

Division result generated.

In a further step 52, it is discriminated whether the number of pulse pattern periods to be generated already corresponds to the time pulse interval 33 or period duration represented by the master sync signal 30. In the present example, the number of pulse pattern periods to be generated is eight

Pulse pattern periods during the pulse spacing 33. If not, the process returns to step 47. If so, that sets The method continues with step 46 in which a new pulse pattern period data record and a new residual data set may be loaded.

FIG. 3 shows an exemplary embodiment of a clock signal which represents the pulse pattern periods generated during the pulse repetition time 33 of the master sync signal 30. Other than previously described, can also be used instead of

Pulse pattern periods pulse pattern half periods are generated. One

Addition of clock pulses can thus take place, for example, on successive half periods. The clock signal 65 includes time

successive pulse pattern periods 53, 54, 55, 56, 57, 58, 59 and 60. The

Pulse pattern period of the first four half periods of

successive pulse pattern periods 53 and 54 are each corresponding to the Divisonsrestergebnis - in this example four slave clock pulses - a clock pulse of the slave clock signal longer than the half periods of the subsequent pulse pattern periods 55, 56, 57, 58, 59 and 60, which in the 2 have been produced in step 51 and their

Period duration corresponds to the pulse pattern period duration data set.

The first half period 61 and the second half period 62 of the pulse pattern period 53, and the first half period 63 and the second half period 64 of the pulse pattern

Periods 54 are each extended by one slave clock pulse, as compared to the half periods of the subsequent pulse pattern periods 55, 56, 57, 58, 59 and 60.

For example, at a period of the master sync signal corresponding to eight PWM periods to be generated by the slave units, a

Division remainder of up to seven clock pulses to eight whole periods or up to fifteen clock pulses to sixteen half periods are distributed.

FIG. 4 shows an exemplary embodiment in which the clocks of the residual data set-unlike in FIG. 3 -are displayed uniformly over the generated pulse pattern.

Signal, comprising consecutive pulse pattern periods, are distributed. The pulse pattern signal 78 illustrated in FIG. 4 comprises eight pulse pattern periods, which follow each other in time. A pulse pattern period 66 has a pulse pattern half-period extended by one clock period of the slave clock signal 74 on. A pulse pattern period 67 immediately following the pulse pattern period 66 is not extended and thus has the period of the pulse duration

Pulse pattern period duration data set on. The pulse pattern period 67 is followed by a pulse pattern period 68 whose period 75 of the first half period is extended by one clock of the slave clock signal. The pulse pattern period 68 is followed by a non-extended pulse pattern period 69 followed by a prolonged one

Pulse pattern period 70, the first half period 76 extended one

Thereupon, it has an unextended pulse pattern period 71 and again an extended pulse pattern period 72 with an extended first half period 77 and finally an eighth pulse pattern period 73 which is unextended. The extended and non-extended pulse pattern periods thus alternate with each other temporally in succession.

The rotor 3 shown in Figure 1 can thereby deliver a torque with a low torque ripple.

FIG. 5 shows a control unit for an electrical machine. The control unit comprises a master unit 80 and a plurality of slave units, which are connected to the master unit 80 via a data bus 85. The data bus is, for example, an SPI data bus (SPI = Serial Peripheral Interface).

A slave unit 81 for a U phase of a three-phase machine is connected to the input side via an input 86, for example a MOSI input (master output slave input) for the master PWM command signal to the master unit 80 and can from the master unit the master PWM

Preset signal received. The slave unit 81 is the output side via an output 87, for example, MISO output (MISO = master input slave output), with another slave unit 82 for a V-phase, and there with an input 88, for example, MOSI Input connected. The slave unit 82 is connected on the output side via an output 89, for example MISO output, to a further slave unit 83 for a W phase, and there to an input 90, for example a MOSI input. On the output side, the slave unit 83 is connected via an output 91, for example MISO output, to a further slave unit 84 for a further phase, where it is connected to an input 92, for example a MOSI input.

In addition to the slave units 81, 82, 83, the control unit may also have further slave units, of which a slave unit 84 is shown by way of example. An output 91 of the slave unit 83, for example a MISO output, is connected to a further slave unit 84 for one phase of a submachine, and there to an input 92, for example a MOSI input.

For example, a control unit for a machine with submachines may have a slave unit for each phase of the submachine. This can be given a high reliability of the machine.

The slave units are in this embodiment for receiving the

Master PWM command signal connected together in series, and thus together form a cascaded arrangement. The master unit 80 has an output 93 for the master sync signal 30. The slave units 81, 82, 83 and 84 are each connected on the input side by means of a common connection line 94 to the output 93 and can receive from there the master sync signal. The connection line 94 may be part of the data bus 85, so that the slave units can receive the master sync signal via the data bus 85. Thus, the reception of the master sync signal, for example, via only a single connection line 94 take place, which of the

Master unit 80 is guided to the slave units.

In a variant of the control unit shown in Figure 5, the master unit 80 is configured to send the master PWM default signal via a slave select output 95 and a connecting line 96 to the slave units. The slave units can each transmit the master PWM command signal via the

Receive connection line 96 at an input for the slave select signal. The master unit 80 is configured, for example, to transmit the master PWM command signal modulated via a slave select connection line. The master unit can do this with a modulator and the slave units each comprise a demodulator for the master P WM command signal. For example, the master PWM command signal may be sent after a slave select signal is sent by the master unit. The corresponding slave unit driven by the slave select signal can then receive the master PWM default signal. The

Connection line 96 for transmitting the slave select signal can

Be part of the data bus 85.

For example, the master unit is formed, the slave select signal and the master PWM command signal are different from each other

Frequency bands to send, which facilitates a signal separation of the slave select signal and the master PWM command signal by the slave units.

Thus, advantageously, the connection lines to the cascaded connection between the slave units, thus omitted between MISO outputs and MOSI inputs.

Shown are also the PWM signals generated by the slave units, in particular a PWM signal 101 generated by the slave unit 81, a PWM signal 102 generated by the slave unit 82, a PWM generated by the slave unit 83 Signal 103 and a PWM signal 104 generated by the other slave unit 84. The PWM signals each generated from mutually different slave units each comprise a PWM period with one

Pulse pattern period 105. The pulse pattern period can be represented by the already mentioned pulse pattern period duration data set.

The PWM signals are respectively generated in synchronism with each other by the slave units at the start time 98 according to the master sync signal 30 and end together at time 99 on the basis of the same period duration 105. The start at the start time 98 and the end at time 99, respectively on a time axis 97 , are thus - in particular within an accuracy of the slave system - independent of one

Frequency deviation of the internal timers of the slave units with each other.

Claims

claims

1 . Electric machine (1) with a stator (2) and a rotor (3), wherein the stator (2) has a plurality of stator coils (4, 5, 6, 7, 8, 9), and at least two output stages (12, 13), which are each connected on the output side to a part of the stator coils (4, 5, 6, 7, 8, 9),

characterized in that

the electrical machine (1) has a master unit (17, 80), which is designed to be a master sync signal (30) for, in particular, indirect

Driving the stator (2) to produce, and the electric machine (1) at least two slave units (15, 16, 81, 82, 83, 84), each having a pulse pattern generator (18, 19) and an input side with the

Pulse pattern generator (18, 19) connected power output stage (12, 13) and are each formed, depending on the master sync signal on

To generate pulse pattern signal for rotating the rotor (3), wherein the slave units (15, 16, 81, 82, 83, 84) are each formed, a

in particular constant slave clock signal (34, 35) for generating the

To generate pulse pattern signal (36, 37) and the master sync signal (30) by means of the slave clock signal (34, 35) to detect, in particular to sample and the pulse pattern signal (36, 37) in dependence of the master sync signal (30) at the same time to generate a pulse pattern clock (65, 78) represented by the pulse pattern signal (36, 37) by the master sync signal (30) so that the simultaneous generation of the pulse pattern signal is independent of a frequency deviation of the slave clock signals can be done with each other.

2. Electrical machine (1) according to claim 1,

characterized in that

the slave unit (15, 16, 81, 82, 83, 84) has an input (26, 27) for the

Master sync signal (30), wherein the master sync signal temporally

has successive, in particular rising or falling edges, and the slave unit (15, 16, 81, 82, 83, 84) has a processing unit (21, 22), which is formed, a number of the clock pulses or clock oscillations of the slave clock signal ( 34), which one by the

Master sync signal (30) represented time interval immediately successive edges and to generate the pulse pattern periods (53, 54, 55, 66, 67, 69) of the pulse pattern signal (36) in accordance with the number of clock pulses.

3. Electrical machine according to one of claims 1 or 2,

characterized in that

the slave unit (15, 16, 81, 82, 83, 84) has an arithmetic unit (21, 22) which is designed to divide the remainder of a clock pulse from a determination of the clock duration of the pulse pattern period to a clock duration of at least indirectly successive pulse pattern periods and thus generate a pulse pattern period (53, 54, 55, 56, 66, 68, 70, 72) with extended cycle time.

4. Electrical machine (1) according to claim 3,

characterized in that

the arithmetic unit (21, 22) is designed to add in each case one clock pulse to chronologically successive pulse pattern periods or pulse pattern half periods (61, 62, 63, 64) until the remainder of the division has been consumed.

5. Electrical machine (1) according to claim 3,

characterized in that

the arithmetic unit (21, 22) is formed on chronologically successive pulse pattern periods (66, 68, 70) or pulse pattern half periods under

Omitting at least one pulse pattern period (67, 69, 71) each adding up a clock pulse until the remainder of the division has been consumed.

6. Electrical machine (1) according to one of the preceding claims, characterized in that

the master unit (17, 80) is adapted to generate a period number signal which is a number of times during a pulse train duration or pulse period of the

Master sync signal (30) to generate pulse pattern periods (53, 54, 55, 66, 67, 69), wherein the slave unit (15, 16, 81, 82, 83, 84) is formed, a clock period, in particular a number of clock pulses of the slave clock signal corresponding to a pulse pattern period (105), depending on

To determine the period number signal.

7. Electrical machine (1) according to one of the preceding claims, characterized in that

the electric machine (1) has a slave unit (15, 16, 81, 82, 83, 84) for each phase of the machine (1).

8. Electrical machine (1) according to one of the preceding claims, characterized in that

the electric machine (1) has at least two submachines (10, 11) each having the same number of phases, the machine having for each submachine (10, 11) at least one slave unit (15, 16, 81, 82, 83 , 84).

9. Electrical machine (1) according to one of the preceding claims, characterized in that

the clock frequency of the slave clock (34) is a multiple of a edge or pulse repetition frequency of the master sync signal (30).

10. Electrical machine (1) according to one of the preceding,

characterized in that

the master unit (17, 80) is adapted to change a period between temporally successive rising or falling edges or pulses of the master sync signal, and thus to control a PWM frequency of the PWM signal generated by the slave unit.

1 1. Electric machine (1) according to one of the preceding claims, characterized in that

the master unit (17, 80) has a modulator which is designed to generate a pulse repetition frequency of the master sync signal (30) by means of a pulse generator

To modulate period duration modulated change or fluctuation of the period of the pulse train, so that a frequency content of the PWM signal is increased in comparison without modulation.

12. An electric drive for an electric vehicle or a hybrid vehicle with an electric machine (1) according to one of the preceding claims, wherein the machine is configured to generate a torque for moving the vehicle.

13. Power steering system for a vehicle having an electric machine (1) according to one of the preceding claims 1 to 1 1, wherein the machine is configured to generate a supporting steering torque for vehicle steering.

14. Method for operating an electrical machine,

in which at least two parts of the stator coils (4, 5, 6, 7, 8, 9) of the machine (1) each form a sub-machine (10, 1 1), wherein the sub-machine (10, 1 1) of one with the sub-machine (10, 1 1) connected to a slave unit (15, 16) forming control unit, wherein a drive pattern for

Bestromen the sub-machine (10, 1 1) of the slave unit (15, 16) is generated, and a time synchronization of the slave units (15, 16, 81, 82, 83, 84) with each other by a time sequence of edges or Pulse

representative master sync signal (30), wherein the slave units (15, 16) each having a timer (24, 25) which generates a slave clock signal (34) for the slave unit independently of the master sync signal and the master sync signal (30 ) is sampled with the timing of the slave clock signal (34) of the slave unit (15, 16) and a number of clock pulses or

Clock oscillations of the slave clock signal (34) to determine which of the master sync signal (30) represented time sequence in particular rising or falling edges and the pulse pattern periods (53, 54, 55, 66, 67, 68) for a rotor circulation accordingly to generate the number of clock pulses.