DE102012012762A1 - Device for determining position of rotor of e.g. brushless direct current (BLDC) motor, has evaluation unit to detect/determine direction of current flow that is introduced through several lines or through interface cables - Google Patents

Abstract

The device has a power unit (3) with electronic power control elements (51,52) of an array (50) for activating the power unit and a higher-level control unit (5). An evaluation unit (9) detects/determines the direction of current flow that is introduced through several lines (28,29,32) or through interface cables (57) of the higher-level control unit, and provides the information about the direction of current flow. The evaluation unit is switched for the detection of current flow direction between a measuring unit (55) and the power unit. An independent claim is included for a method for determining position of rotor of electric machine.

Description

The invention relates to a device and a method for determining positions of a rotor in electrical machines and relates to the control of brushless DC motors (BLDC motors) or permanent magnet synchronous machines (PMSM) or synchronous machines in general.

A typical setup of a facility 1 for controlling the machines 2 is in 1 shown.

• – ein Leistungsteil 3, das unmittelbar mit der Maschinen in Verbindung steht,
• – eine Messeinrichtung 4, die mit dem Leistungsteil 3 verbunden ist,
• – eine Regelungseinrichtung 5, die an die Messeinrichtung 4 angeschlossen ist, sowie
• – eine Spannungsversorgungseinheit 6, die mit dem Leistungsteil 3, mit der Messeinrichtung 4 und der Regelungseinrichtung 5 in Verbindung steht.

This is the device 1 to the machine 2 connected, the device 1 essentially comprises

• - a power section 3 which is directly related to the machines,
• - a measuring device 4 that with the power section 3 connected is,
• - a control device 5 to the measuring device 4 connected as well
• - a power supply unit 6 that with the power section 3 , with the measuring device 4 and the control device 5 communicates.

The synchronous machine can be designed both as an internal rotor and as an external rotor. Such a machine is in the document DE 2 511 567 A1 described, which includes a rotor provided with permanent magnets and a stator disposed on the polyphase winding, each phase of the winding having at least one forming coil, that the forming coils are formed substantially equal and that at the intersection of the coil heads each of the head of the following in the circumferential direction Coil and phase is located above the previous coil, using conventional electronics 1 be used. For the purpose of applying the currents flowing through phases of the winding of a DC motor, signals corresponding to the respective rotor position are required. For this purpose, the voltage induced by the rotation of the rotor in the individual forming coils is measured by the electronics 1 evaluated. The Electronic 1 generates from this control signals for energizing the shaping coils. The energization ensures the rotational movement of the rotor.

The respective machine - internal rotor or external rotor - can be used both a machine in delta connection as well as for a machine in star connection. The machines are connected in each case via the connections stranded with a device for commutation and position detection.

To operate the brushless DC motors (BLDC motors) or permanent magnet synchronous machines (PMSM) or synchronous machines permanent measurement and monitoring of the position of the rotor are necessary. For this purpose, there are currently a large number of sensor-based as well as sensorless methods for measuring at least one position of the rotor of a machine during a rotation of the rotor.

State of the art

A method for sensor-based position measurement for BLDC motors is in the Reference AVR443: Sensor-based conrol of three-phase Brushless DC motor, available at http://www.atmel.com/Images/doc2596.pdf dated February 2006 , described. The advantage of the method is that the positions of the rotor are permanent and independent of the driving of the motor.

However, the implementation also has several disadvantages. Implementing the sensors requires additional hardware that makes the overall product more expensive. In addition, the allowable temperature range of such sensors is usually limited (typically 85 ° C), so they can not be used in high temperature applications.

Another method for sensorless position measurement with the following conditions is in the Reference AVR444: Sensorless control of 3-phase brushless DC motors, available at http://www.atmel.com/Images/doc8012.pdf dated October 2005 described. In this case, a motor is energized on two of three phases. At the third, de-energized phase, the EMF is measured back. The method can be reliably used as soon as a sufficiently high EMF is available. It also assumes that a phase is de-energized at the time of measurement. As a result, the shape of the control is limited to a block commutation with the disadvantages that the torque of the machine has a high ripple. pamphlet DE 10 2007 063 386 A1 also describes this method.

Another problem of the control is that there is a strong noise and also a non-optimal efficiency of the application. For optimum efficiency with minimal noise development, a sinusoidal control with a suitable position measurement would be necessary. Suitable for this means that no current-negative phase is required for position measurement, since with sinusoidal control, all three phases of the machine are always counted.

Other methods for performing a sinusoidal drive of a motor are in the Specification Perassi: Field-oriented control of the permanent-magnet synchronous machine without position encoder for the entire speed range until standstill, at the Internet address. http://db-thueringen.de/Servlets/Derivate Servlet / Derivatives-13770 / ilm1-2007000172.pdf from 04.12.2006 described.

For this the current increase is measured. The current rise measurement makes high demands in relation to a large number of components / components in the current measurement path, so that a high level of hardware effort is also created in this case.

Another device and an associated method for determining the position of sensorless electrical machines is in the document US 5,254,914 A described, wherein prior to starting short current pulses are fed into the individual phases and the duration is measured until the decay of the voltage at the respective port. For this purpose, the terminal voltage is compared with the voltage of the actual neutral point of the electrical machine and evaluated. To generate the current pulses for the measurement, a simple power unit is not suitable and an additional realization effort is necessary. Furthermore, the method is exclusively applicable to electrical machines in star connection, in which the neutral point is led out as an additional line. Many machines either do not lead out the neutral point or are connected in delta connection. Then the procedure is not applicable.

A foreign-excited electric machine is in the document EP 1 005 716 described, wherein for position determination briefly applied voltages to the individual phases and the voltage at the actual neutral point of the electrical machine are evaluated. To apply the voltages, the existing power unit can be used without extensions, resulting in a significant reduction of the necessary implementation costs compared to that in the document US 5,254,914 A specified device leads. However, the problem associated with the evaluation of the actual neutral point voltage of the electrical machine, the severe limitation of the applicability of the method in various applications remains. An apparatus and a method for rotor position determination is in Dobrucky, Filka, Spanik, Zigmund: Real-Time PMSM Rotor Position Estimator. Based on Virtual HF Injection Method (VHFIM), In proc. EPE '05, September 2005, Dresden described in which no lead out star point is needed. For this purpose, however, a high-frequency (HF) signal is fed into the individual strands and the filtered signal is evaluated.

One problem is that the method, however, requires an enormous additional implementation effort for generating, feeding and evaluating the RF signal.

Overall, it can be summarized that, as soon as a sinusoidal control of a motor is to be made, high demands are placed on the position measurement of the rotor, which lead to additional hardware complexity and / or additional algorithmic effort.

In devices for controlling BLDC motors or permanent-magnet-excited synchronous machines, it is always necessary to generate at least one phase with a fixed frequency or variable frequency in order to generate the drive signals. When switching often undesirable vibrations occur during the switching operations, which cause increased noise radiation and thus can significantly affect both other systems and the system itself to functional failure or destruction.

An apparatus and a method for direct commutation between series-connected power electronic actuators are in the document DE 10 2008 026 499 A1 and a method and apparatus for controlling the commutation rate between series connected power electronic actuators with inductive load are disclosed in the document DE 10 2008 026 500 A1 described in which the emission of radiation should be minimized.

The structure of such a device with the associated method according to document DE 10 2008 026 499 A1 is in 2 shown. In engine control systems, therefore, the use of such a method is recommended.

In the device for direct commutation between series-connected power electronic actuators in a circuit breaker assembly with inductive load according to document DE 10 2008 026 499 A1 the actuators are arranged between a positive supply potential VS and a negative supply potential GND, of which at least two actuators are actively switched on and off and are connected via control signal lines to a drive circuit which contains a central control unit with sub-circuits therein, wherein the drive circuit is a higher-level Programming and control unit is connected upstream.

• – eine Mess- und Bewertungsschaltung, welche Verbindungen zu mindestens einem Messsignalabgriff und zu mindestens einer Signalleitung der Steuervorgabeschnittstelle besitzt und über Zustandserfassungsleitungen Signale an die zentrale Steuereinheit überträgt, wobei die Signale der Zustandserfassungsleitungen in Verbindung zum Beginn und zum Ende der Kommutierung stehen,
• – die zentrale Steuereinheit, welches mit der Mess- und Bewertungsschaltung über die Zustandserfassungsleitungen verbunden ist und mittels mindestens einer Signalleitung mit der Steuervorgabeschnittstelle und mittels mindestens einer Signalleitung zur Vorgabe von Zeitparametern auf der ersten Programmierschnittstelle mit der übergeordneten Programmier- und Steuereinheit in Verbindung steht,
• – eine Hilfssignalschaltung, welche mit der zentralen Steuereinheit durch Totzeit-Parameterübergabeleitungen, durch Schaltzeit-Parameterübergabeleitungen und durch Hilfssignalrückführungsleitungen in Verbindung steht und mittels mindestens einer Signalleitung der Steuervorgabeschnittstelle mit der übergeordneten Programmier und Steuereinheit verbunden ist,
• – mindestens zwei Ansteuerteilschaltungen, welche über Hilfssignalleitungen mit der Hilfssignalschaltung verbunden sind, und
• – mindestens zwei Treiberschaltungen, die jeweils mindestens zwei Treiberteilstromquellen enthalten und die über Treibersteuerleitungen mit den Ansteuerteilschaltungen verbunden sind und mittels Signalleitungen zur Vorgabe der Treiberteilstromniveaus auf der zweiten Programmierschnittstelle mit der übergeordneten Programmier- und Steuereinheit in Verbindung stehen sowie über die Steuersignalleitungen mit der Leistungsschalteranordnung verbunden sind.

At least two actively switching actuators are connected by the control signal lines to the drive circuit, wherein the drive circuit receives by at least one Meßsignalabgriff measured variables from the circuit breaker assembly and drive sequences for the active switching Actuators via the control signal lines in response to the signal on a Steuerervorgabeschnittstelle and further specifications on two programming interfaces generated to the parent programming and control unit, the drive circuit may include the following modules:

• A measurement and evaluation circuit which has connections to at least one measurement signal tap and to at least one signal line of the control interface and transmits signals to the central control unit via state sense lines, the signals of the state sense lines being connected to the start and end of the commutation,
• The central control unit which is connected to the measurement and evaluation circuit via the state detection lines and is connected to the higher-level programming and control unit by means of at least one signal line with the control interface interface and by means of at least one signal line for specifying time parameters on the first programming interface;
• An auxiliary signal circuit, which is connected to the central control unit by dead time parameter transfer lines, by switching time parameter transfer lines and by auxiliary signal return lines and is connected to the higher-level programming and control unit by means of at least one signal line of the control interface;
• - At least two Ansteuerteilschaltungen, which are connected via auxiliary signal lines to the auxiliary signal circuit, and
• - At least two driver circuits, each containing at least two driver partial current sources and are connected via driver control lines to the Ansteuerteilschaltungen and connected by signal lines for specifying the driver Teilstromniveaus on the second programming interface with the parent programming and control unit and are connected via the control signal lines to the circuit breaker assembly ,

• – eine gleichzeitige Ansteuerung der beiden aktiv schaltenden Stellglieder derart, dass bei jedem Schaltvorgang eine direkte Stromübernahme zwischen der beiden aktiv schaltenden Stellgliedern stattfindet, mittels Ansteuersignalen aus der Ansteuerschaltung, wobei
• – eine Erfassung des Zeitpunktes des Beginns der Kommutierung,
• – eine schrittweise Regelung des Totzeitparameters unter Nutzung des Zeitpunktes des Beginns der Kommutierung und
• – eine Erfassung des Zeitpunktes des Endes der Kommutierung

durchgeführt werden.In the associated method take place

• - A simultaneous control of the two active-switching actuators such that each switching operation, a direct current transfer between the two active switching actuators takes place by means of control signals from the drive circuit, said
• A detection of the time of the beginning of the commutation,
• A stepwise regulation of the deadtime parameter using the time of the beginning of the commutation and
• - A recording of the time of the end of the commutation

be performed.

A problem of the devices according to the documents DE 10 2008 026 499 A1 and DE 10 2008 026 500 A1 consists in that the current flow direction is inherently determined in the process but no signal usable for determining the position is forwarded to the higher-level control and regulation unit.

Object of the invention

The invention is therefore based on the object to provide a device and a method for determining positions of a rotor in electrical machines, which are designed so suitable that the current flow direction determined in the individual phases of the rotor of the electric machine and the parent control and Control unit can be evaluated and that a sinusoidal control of the electrical machines is allowed, without generating a high additional hardware cost.

The object is solved by the features of claims 1 - device - and 21 - method.

The device for determining the position of the rotor of electric machines, which are provided with a stator in addition to the rotor, exists at least
from a power unit with power electronic actuators,
from an arrangement for controlling the power unit as well
from a higher-level control unit,
wherein according to the characterizing part of patent claim 1
an evaluation unit for detecting / determining the current flow direction is introduced, which permanently provides the information about the current flow direction sign (I) via one or more lines or via an interface of the superordinate control unit.

• – ein Leistungsteil mit leistungselektronischen Stellgliedern, die an den Rotor angeschlossen sind,
• – eine Anordnung zum Ansteuern der leistungselektronischen Stellglieder,
• – eine Messeinrichtung, die Signale zur Verfügung stellt,
• – eine übergeordnete Steuereinheit zur Ansteuerung der elektrischen Maschine,

wobei die Messeinrichtung ein Signal zur Verfügung stellt, an dem die Stromflussrichtung sign(I) festgestellt werden kann, und die Anordnung zur Erkennung/Feststellung der Stromflussrichtung sign(I) eine Auswerteeinheit zur Auswertung des von der Messeinrichtung übermittelten Signals zu Feststellung der Stromflussrichtung sign(I) im Rotor der Maschine enthält.The device for determining positions of a rotor in electrical machines, which is provided with a stator in addition to the rotor, comprises at least

• A power section with power electronic actuators connected to the rotor,
• An arrangement for controlling the power electronic actuators,
• - a measuring device that provides signals,
• A higher-level control unit for controlling the electrical machine,

wherein the measuring device provides a signal at which the current flow direction sign (I) can be detected, and the arrangement for detecting / determining the current flow direction sign (I) an evaluation unit for evaluating the signal transmitted by the measuring device to determine the current flow direction sign ( I) in the rotor of the machine.

• – zwei den Flip-Flops nachgeordnete, parallel angeordnete ODER-Glieder und
• – ausgangsseitig ein den ODER-Gliedern nachgeschaltetes XOR-Glied.

The evaluation unit for determining the current flow direction is connected between the measuring device and the power unit and contains at least on the input side four arranged flip-flops,

• - Two downstream of the flip-flops, arranged in parallel OR gates and
• - On the output side of the OR gates downstream XOR gate.

The aforementioned components of the evaluation unit are interconnected in such a way,
from the output lines of the arrangement for detection from the beginning of the commutation and the end of the commutation (measuring device) to the first flip-flop and the second flip-flop, the output lines out, while the third flip-flop and the fourth flip-flop the Output line is guided, wherein the RESET inputs R of the four parallel flip-flops lines are guided, which are in communication with the PWM signals leading output line and which are operated with the PWM signal from the parent control unit,
wherein the first flip-flop and the fourth flip-flop, the OR gate is connected downstream and the second flip-flop and the third flip-flop, the second OR gate,
wherein from the output Q of the first flip-flop, a signal line is fed to one of the inputs of the first OR gate for transmitting the free-wheeling signal FRW_LS_H,
wherein a signal line is led from the output Q of the fourth flip-flop to the other input of the first OR gate for transmitting the free-wheeling signal FRW_LS_L,
wherein the output Q of the second flip-flop a signal line to one of the inputs of the second OR gate for transmitting the freewheel signal FRW_HS_L is performed,
wherein from the output Q of the third flip-flop, a signal line is fed to the second input of the second OR gate for transmitting the free-wheeling signal FRW_HS_H,
wherein from the output of the first OR gate, a signal line to the higher-level control unit, on which the freewheel signal FRW_LS is transmitted, and the output of the second OR gate, a signal line to the higher-level control unit, on which the freewheel signal FRW_HS is transmitted out,
wherein a first branch line of the signal line is led to the first input of the XOR gate and a second branch line of the signal line is led to the second input of the XOR gate,
wherein the XOR gate, a signal line is guided to the higher-level signal line on which the confirmation signal "valid" is transmitted.

The electric machine having at least one rotor may be a BLDC motor or a permanent-magnet-excited synchronous machine.

The measuring device may contain two comparators which compare the voltage at the upper measuring point MP with a positive reference voltage and a negative reference voltage, the output signal didt_p indicating a positive current change and the output signal didt_n indicating a negative current change at the relevant switching edge.

In the evaluation unit, the output signal FRW_LS indicates that the current flow direction from the motor is directed into the phase connection of the power unit, wherein the output signal FRW_HS indicates that the current flow direction is directed from the power unit to the motor and the output signal "valid" indicates that the output of the evaluation unit correct is.

The evaluation unit can be contained in a system for motor control, which consists of the known device described in the document DE 10 2008 026 499 A1 is described, wherein additionally in a central control unit, the arrangement is inserted, wherein the output of this module is guided via one or more separate lines to the higher-level control unit and the method for synchronizing the position in the parent control unit 5 is performed.

The information about the current direction in the phase connections can be transmitted instead of via separate lines via the already existing interface of the evaluation to the parent control unit.

The evaluation units can be used in a conventional system for the control of BLDC motors and permanent magnet synchronous machines 2 integrated according to the prior art, wherein the output of the evaluation unit is connected via a line to the superordinate control unit and it provides the information about the current flow direction in the phase terminals.

At extremely low load current, the current change in the inductance at the switching edges may not be sufficient to hold the comparators safely triggering, wherein the output signal "valid" to low level and another possibility of determining the sign sign (I) of the current I _MOT (t) or another type of detection of positions of a rotor triggers.

In the evaluation unit for current direction detection can be detected for low load currents freewheel on power electronic actuator to the negative supply voltage, the function of the evaluation a small dead time when switching the power electronic actuators is necessary, within this dead time a comparator unit, the phase voltage U _PH (t) compares with a low negative voltage, wherein a reset signal R resets the flip-flop at the beginning of each switching edge, and when a freewheel on the power electronic actuator to the negative supply voltage (-0.2 V) occurs, the flip-flop is set.

The method for determining the position of the rotor of electric machines, with an aforementioned arrangement consisting at least of the motor with at least one rotor and a stator, with a power unit with power electronic actuators, with an arrangement for controlling the power unit and with a higher-level control unit,
according to claim 21 has the following step,
the generation of the drive signals for the electric machine is effected such that the reversal of the direction of current flow in at least one phase takes place at a specific time within the generation of the output average phase voltage U _PH .

The target time for the reversal of the current flow direction may be the sign change ± sign (I) of the mean drive voltage of the relevant phase or the achievement of the average drive voltage of half the positive supply voltage.

The target time for the reversal of the current flow direction may be a constant time before the zero crossing or after the zero crossing of the average phase voltage or the achievement of the average phase voltage U _PH of half the positive supply voltage.

The target time for the reversal of the current flow direction can be given by a constant phase shift relative to the zero crossing of the average phase voltage or the achievement of the average phase voltage U _PH of half the positive supply voltage.

The phase shift or the time difference may be varied depending on the detected position of the rotor to avoid geometric inaccuracies of the machine 2 to compensate.

The essence of the invention is that for position detection, the sign of the current I _MOT (t) to at least one phase of the rotor of the machine ( 2 ) is monitored and the sign change is synchronized with the time course of the generated phase voltage U _PH (t).

Further developments and advantageous embodiments of the invention are specified in further subclaims.

The invention will be explained with reference to exemplary embodiments by means of several drawings.

Show it:

1 a structure of a conventional means for controlling an electric machine, for. As for brushless DC motors (BLDC motors) or permanent magnet synchronous machines (PMSM) or synchronous machines in general,

2 an arrangement for reducing the noise emission according to document DE 10 2008 026 499 A1 .

3 Time curves of phase voltage and EMF ( 3a ) as well as phase current ( 3b ) in one phase of the engine control system,

4 an output of the current direction in an application of the method according to the invention,

5 an arrangement for detecting the beginning of a commutation and the end of a commutation of the power electronic actuators according to the prior art,

6 an arrangement for detecting the current flow direction in the phase according to the invention,

7 an arrangement for detecting the current flow direction at low load current according to the invention,

8th an arrangement for resetting the arrangement 7 according to the invention,

9 an expanded arrangement according to the invention for the low-noise switching and simultaneous driving of a BLDC motor or a permanent-magnet-excited synchronous machine,
and

10 an inventive arrangement for driving BLDC motors or permanent magnet synchronous machines.

In the 3a and 3b the course of the generated phase voltage U _PH (t) and the EMK -U _EMK (t) of the motor ( 3a ) and the course of the associated phase current I _MOT (t) ( 3b ) are each shown over the time t.

The method proposed here evaluates the sign sign (I) of the phase current I _PH (t) and brings the instant t _{W of} the sign change ± sign (I) of the phase current I _MOT (t) in accordance with the time course of the phase voltage U _PH (t ). For this purpose, information about the sign sign (I) of the phase current I _MOT (t) is necessary. This information of the sign sign (I) is in 4 shown.

• – das Vorzeichen sign(I) des Stroms I_MOT(t) zu einem bestimmten Zeitpunkt t abgefragt werden und eine entsprechende Generierung eines Korrektursignals erfolgen oder
• – der Zeitpunkt t_W (in 4) des Vorzeichenwechsels ±sign(I) des Phasenstroms I_MOT(t) vom Verfahren abgefragt und je nach Lage innerhalb der Generierung der Phasenspannung U_PH(t) auch dort ein korrigierender Eingriff in die Generierung der Phasenspannung U_PH(t) vorgenommen werden.

The method according to the invention has the goal of changing the sign change from + sign (I) to -sign (I) or vice versa, corresponds in the following to sign (I), of the current I _MOT (t) with the output phase voltage U _PH (t) synchronize. This can either

• - The sign sign (I) of the current I _MOT (t) are queried at a certain time t and carried out a corresponding generation of a correction signal or
• - the time t _W (in 4 ) of the sign change ± sign (I) of the phase current I _MOT (t) queried by the method and depending on the location within the generation of the phase voltage U _PH (t) also there a corrective intervention in the generation of the phase voltage U _PH (t) are made.

For this purpose, the frequency of the generated phase voltage U _PH (t) is either reduced or increased, so that in the steady state the sign change ± sign (I) of the phase current I _MOT (t) preferably simultaneously with the sign change ± sign (I) of the phase voltage U _PH (t) occurs. The measurement can z. B. once per one electrical revolution of the rotor or up to six times per one electrical revolution of the rotor or even less frequently performed. The more often the evaluation of the sign change ± sign (I) takes place, the faster the method can react to speed changes or load changes of the rotor. The less frequently the evaluation takes place, the lower the requirement for the processing speed of the device 1 for control of the engine 2 ,

For parametric adaptation to the time constants of the motor 2 For example, the method can also control a time shift of the zero crossings of the phase current I _MOT (t) and the generated phase voltage U _PH (t). The time shift can z. B. depending on parameters of the engine 2 how inductance but also of load conditions and amplitude of the motor current I _MOT (t) are generated.

• – einen Leistungsteil 3 mit leistungselektronischen Stellgliedern,
• – eine Anordnung 50 zum Ansteuern der leistungselektronischen Stellglieder,
• – eine Messeinrichtung 55, die mit einer Messinduktivität 54 verbunden ist und die ausgangsseitig Signale 56 zur Verfügung stellt,
• – eine übergeordnete Steuereinheit 5 zur Ansteuerung der elektrischen Maschine 2, z. B. des BLDC-Motors oder der permanentmagneterregten Synchronmaschine.

The device belonging to the procedure 1 for an electric machine 2 with rotor and stator, z. As a BLDC motor or a permanent magnet synchronous machine, according to the prior art comprises at least

• - a power unit 3 with power electronic actuators,
• - an arrangement 50 for driving the power electronic actuators,
• - a measuring device 55 that with a measuring inductance 54 is connected and the output side signals 56 provides
• - a higher-level control unit 5 for controlling the electric machine 2 , z. B. the BLDC motor or the permanent magnet synchronous machine.

Most of the mentioned units are already contained in known devices for driving, but do not contain any detection of positions of a rotor.

• – die Messeinrichtung 55, die mit einer Messinduktivität 54 verbunden ist und ein Signal zur Verfügung stellt, an dem die Flussrichtung des Stromes I_MOT(t) festgestellt werden kann, und
• – die Auswerteeinheit 9 zur Erkennung/Feststellung der Stromflussrichtung.

According to the invention, the following must be added to the control:

• - the measuring device 55 that with a measuring inductance 54 is connected and provides a signal at which the flow direction of the current I _MOT (t) can be detected, and
• - the evaluation unit 9 for detecting / determining the current flow direction.

Particularly interesting is the application of the method proposed here, if one of the methods described in the document DE 10 2008 026 499 A1 or in the publication DE 10 2008 026 500 A1 are used, since these are the measuring device 55 that a signal 56 contains, at which the current flow direction can be determined already contains. Thus, there is only the evaluation to complete the detection / determination of the current flow direction. Since this is purely digitally feasible, in modern application systems which have a high integration density, practically no additional costs are incurred.

A preferred embodiment of the measuring device 55 , which provides a signal at which the current flow direction can be detected, is in 2 and 5 shown.

A (often already in the structure contained parasitic) inductance 54 , as in 2 is shown, at each switching edge, the current change in the power electronic actuator 51 . 52 become measurable to the negative supply voltage to let. These are two comparators 7 and 8th used as in 5 shown. The first comparator 7 compares the voltage at the upper measuring point MP with a positive reference voltage + Vref and the second comparator connected in parallel 8th compares the voltage at the upper measuring point MP with a negative reference voltage -Vref. The output didt_p of the first comparator 7 indicates a positive current change and the output didt_n of the second comparator 8th indicates a negative current change at the relevant switching edge.

The evaluation unit according to the invention 9 for detecting / determining the current flow direction evaluates the from the comparators 7 and 8th transmitted output signals didt_p and didt_n together with the controlling pulse width modulation (PWM) signal provided by the higher level programming and control unit 5 over the line 20 is provided. A preferred embodiment of the evaluation unit 9 is in 6 shown.

• – eingangsseitig vier Flip-Flops 10, 11, 12, 13,
• – zwei den Flip-Flops 10, 11, 12, 13 nachgeordnete ODER-Glieder 21, 22 und
• – ausgangsseitig ein den ODER-Gliedern 21, 22 nachgeschaltetes XOR-Glied 27,

die derart miteinander verschaltet sind,
dass
von den Ausgangsleitungen 14, 15 der Anordnung zur Detektion vom Beginn der Kommutierung und Ende der Kommutierung (Messeinrichtung 55) aus an das erste Flip-Flop 10 und das zweite Flip-Flop 11 die Ausgangsleitungen 14 geführt, während an das dritte Flip-Flop 12 und das vierte Flip-Flop 13 die Ausgangsleitung 15 geführt ist,
wobei an die RESET-Eingänge R der vier Flip-Flops 10, 11, 12, 13 Leitungen 16, 17, 18, 19 geführt sind, die mit der PWM-Signale führenden Ausgangsleitung 20 in Verbindung stehen und die mit diesem PWM-Signal von Seiten der übergeordneten Steuereinheit 5 bedient werden,
wobei dem ersten Flip-Flop 10 und dem vierten Flip-Flop 13 das ODER-Glied 21 nachgeschaltet ist und
dem zweiten Flip-Flop 11 und dem dritten Flip-Flop 13 das zweite ODER-Glied 22 nachgeschaltet ist,
wobei vom Ausgang Q des ersten Flip-Flops 10 eine Signalleitung 23 an einen der Eingänge des ersten ODER-Gliedes 21 zur Übertragung des Freilaufsignals FRW_LS_H geführt ist,
wobei vom Ausgang Q des vierten Flip-Flops 13 eine Signalleitung 24 an den anderen Eingang des ersten ODER-Gliedes 21 zur Übertragung des Freilaufsignals FRW_LS_L geführt ist,
wobei vom Ausgang Q des zweiten Flip-Flops 11 eine Signalleitung 25 an einen der Eingänge des zweiten ODER-Gliedes 22 zur Übertragung des Freilaufsignals FRW_HS_L geführt ist,
wobei vom Ausgang Q des dritten Flip-Flops 12 eine Signalleitung 26 an den zweiten Eingang des zweiten ODER-Gliedes 22 zur Übertragung des Freilaufsignals FRW_HS_H geführt ist,
wobei vom Ausgang des ersten ODER-Gliedes 21 eine Signalleitung 28 zur übergeordneten Steuereinheit 5, auf der das Freilaufsignal FRW_LS übertragen wird, und vom Ausgang des zweiten ODER-Gliedes 22 eine Signalleitung 29 zur übergeordneten Steuereinheit 5, auf der das Freilaufsignals FRW_HS übertragen wird, geführt sind,
wobei eine erste Abzweigleitung 30 der Signalleitung 28 an den ersten Eingang des XOR-Gliedes 27 geführt und eine zweite Abzweigleitung 31 der Signalleitung 29 an den zweiten Eingang des XOR-Gliedes 27 geführt sind,
wobei vom XOR-Glied 27 eine Signalleitung 32 an die übergeordnete Signalleitung 5 geführt ist, auf der das Bestätigungssignal „valid” übertragen wird.The evaluation unit 9 includes at least

• - Four flip-flops on the input side 10 . 11 . 12 . 13 .
• - two of the flip-flops 10 . 11 . 12 . 13 downstream OR members 21 . 22 and
• - On the output side, the OR elements 21 . 22 downstream XOR element 27 .

which are interconnected in such a way
that
from the output lines 14 . 15 the arrangement for detection of the beginning of the commutation and end of the commutation (measuring device 55 ) off to the first flip-flop 10 and the second flip-flop 11 the output lines 14 passed while on the third flip-flop 12 and the fourth flip-flop 13 the output line 15 is guided,
being to the RESET inputs R of the four flip-flops 10 . 11 . 12 . 13 cables 16 . 17 . 18 . 19 are guided, with the PWM signals leading output line 20 and communicate with this PWM signal from the parent control unit 5 to be served,
wherein the first flip-flop 10 and the fourth flip-flop 13 the OR gate 21 is downstream and
the second flip-flop 11 and the third flip-flop 13 the second OR gate 22 is downstream,
from the output Q of the first flip-flop 10 a signal line 23 to one of the inputs of the first OR gate 21 is conducted to transmit the freewheel signal FRW_LS_H,
from the output Q of the fourth flip-flop 13 a signal line 24 to the other input of the first OR gate 21 for the transmission of the freewheel signal FRW_LS_L is performed,
from the output Q of the second flip-flop 11 a signal line 25 to one of the inputs of the second OR gate 22 is carried to transmit the freewheel signal FRW_HS_L,
from the output Q of the third flip-flop 12 a signal line 26 to the second input of the second OR gate 22 is conducted to transmit the freewheel signal FRW_HS_H,
being the output of the first OR gate 21 a signal line 28 to the higher-level control unit 5 on which the freewheel signal FRW_LS is transmitted, and the output of the second OR gate 22 a signal line 29 to the higher-level control unit 5 , on which the freewheeling signal FRW_HS is transmitted, are guided,
wherein a first branch line 30 the signal line 28 to the first input of the XOR gate 27 guided and a second branch line 31 the signal line 29 to the second input of the XOR gate 27 are guided,
where from the XOR member 27 a signal line 32 to the higher-level signal line 5 on which the confirmation signal "valid" is transmitted.

The structure is interconnected such that, if valid signal didt_p or didt_n is available, exactly one of the flip-flops always outputs a '1' signal. In the time interval PWM = '1' gives the flip-flop 10 a '1' off, if didt_p = '1' or flip-flop 12 returns a '1' if didt_n = '1'. In the time interval PWM = '0' gives the flip-flop 11 a '1' off, if didt_p = '1' or flip-flop 13 returns a '1' if didt_n = '1'. The two OR gates each combine a signal pair for PWM = '1' and PWM = '0' together to form an output signal FRW_LS or FRW_HS. The XOR gate monitors that exactly one of the two signals FRW_LS and FRW_HS, 1 'is always. Then the output signal is a valid signal and the valid signal is activated. Otherwise, the output signal is not valid and valid = '0' is output.

The output signal FRW_LS indicates that the current flow direction from the rotor of the motor 2 in the phase connection of the power unit 3 is directed. The output signal FRW_HS indicates that the current flow direction from the power section 3 in the rotor of the engine 2 is directed. The output signal "valid" indicates that the output of the evaluation unit 9 correct is.

The measurement of the current flow direction with the inductance requires a minimum current in the application in order to function correctly. In some special cases with extremely low load current, it may be necessary for the current variation in the inductance at the switching edges to be insufficient for the comparators 7 and 8th out 5 safely trigger. In this case, the output signal "valid" can change to low level and another way of determining the sign sign (I) of the current or another type of detection of positions of a rotor is necessary.

In this case, another preferred form of the arrangement 33 for current direction detection for low load currents in 7 shown.

• – eine Vergleichereinheit 34, an deren Eingänge eine erste Signalleitung 35 zur Übertragung der Phasenspannung UPH(t) und eine zweite Signalleitung 36 zur Übertragung der Lastspannung (–0,2 V) geführt sind,
• – ein Flip-Flop 37, dessen erster Eingang mit der Ausgangsleitung 38 zur Signalübertragung des Vergleicherergebnisses und dessen zweiter Eingang D mit „1” beaufschlagt wird, wobei vom Ausgang des Flip-Flops 37 eine Signalleitung 39 an die übergeordnete Steuereinheit 5 geführt ist.

The order 33 includes

• - a comparator unit 34 , at whose inputs a first signal line 35 for transmitting the phase voltage UPH (t) and a second signal line 36 for the transmission of the load voltage (-0.2 V) are performed,
• - a flip-flop 37 , whose first input to the output line 38 for signal transmission of the comparison result and whose second input D is applied with "1", wherein the output of the flip-flop 37 a signal line 39 to the higher-level control unit 5 is guided.

• – einen Negator 41 und
• – ein XOR-Glied 42, das über seine Ausgangsleitung 43 das Signal R zum Rücksetzen übermittelt.

In the arrangement 33 a freewheel is detected at the power electronic actuator to the negative supply voltage. For proper operation of this arrangement 33 a small dead time when switching the power electronic actuators is necessary. Within this dead time, a comparator unit compares 34 the phase voltage U _PH (t) with a low negative voltage (-0.2 V). A reset signal R sets the flip-flop 37 back at the beginning of each switching edge. If a freewheel on the power electronics actuator to negative supply voltage (-0.2 V), so is the flip-flop 37 set. A preferred edge detector arrangement 40 to reset the flip-flop 37 on each flank is in 8th shown. It generates a short pulse at each incoming edge, the edge detector arrangement 40 at least includes:

• - a negator 41 and
• - an XOR member 42 that's about his output line 43 the signal R is transmitted for resetting.

Another embodiment in which the phase voltage U _{PH is} compared with a positive supply voltage or a reference voltage may also be provided.

A preferred form of implementation of the presented method and the device in a system for motor control are in 9 shown. It consists of the arrangement in the publication DE 10 2008 026 499 A1 is described. In addition, in the block "Central control unit" 53 the evaluation unit 9 out 6 inserted. The output of the evaluation unit 9 is via one or more separate lines 28 . 29 . 32 to the higher-level control unit 5 guided. The method of synchronizing the position of the rotor of the motor 2 is in the parent control unit 5 executed.

In a further preferred embodiment of the invention, the information about the current direction in the phase terminals instead of via separate lines via the existing interface 57 from the evaluation unit 9 to the higher-level control unit 5 transfer.

Another preferred embodiment according to the invention is in 10 shown. In this embodiment, no device is used for low-noise switching. The arrangements 4 and 9 to 5 and 6 are in a conventional system for the control of BLDC motors and permanent magnet synchronous machines 2 Integrated according to the prior art. The output of the evaluation unit 9 is via a line with the parent control unit 5 Connected and provides her the information about the current flow direction in the phase terminals.

LIST OF REFERENCE NUMBERS

1

Facility

2

machine

3

power unit

4

Measuring device according to the prior art

5

Control device / higher-level control unit

6

Power supply unit

7

First comparator

8th

Second comparator

9

evaluation

10

First flip-flop

11

Second flip-flop

12

Third flip-flop

13

Fourth flip-flop

14

output line

15

output line

16

management

17

management

18

management

19

management

20

output line

21

First OR member

22

Second OR member

23

signal line

24

signal line

25

signal line

26

signal line

27

XOR gate

28

signal line

29

signal line

30

First branch line

31

Second branch line

32

signal line

33

Arrangement for determining the current direction

34

comparator unit

35

signal line

36

voltage line

37

Flip-flop

38

output line

39

output line

40

arrangement

41

negator

42

XOR gate

43

Output signal line

50

Arrangement for driving power electronic actuators

51

first actuator

52

second actuator

53

central control unit

54

measuring inductance

55

Measuring device for the detection of current commutation

56

management

57

Interface / Interface cables

U _PH (t)

phase voltage

I _MOT (t)

phase current

Vref

reference voltage

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely 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.

Cited patent literature

• DE 2511567 A1 [0004]
• DE 102007063386 A1 [0009]
• US 5254914 A [0013, 0014]
• EP 1005716 [0014]
• DE 102008026499 A1 [0018, 0019, 0020, 0023, 0033, 0048, 0065, 0077]
• DE 102008026500 A1 [0018, 0023, 0065]

Cited non-patent literature

• Publication AVR443: Sensor-based conrol of three-phase Brushless DC motor, available at http://www.atmel.com/Images/doc2596.pdf dated February 2006 [0007]
• Reference AVR444: Sensorless control of 3-phase brushless DC motors, available at http://www.atmel.com/Images/doc8012.pdf dated October 2005 [0009]
• Specification Perassi: Field-oriented control of the permanent-magnet synchronous machine without position encoder for the entire speed range until standstill, at the Internet address. http://db-thueringen.de/Servlets/Derivate Servlet / Derivatives-13770 / ilm1-2007000172.pdf from 04.12.2006 [0011]
• Dobrucky, Filka, Spanik, Zigmund: Real-Time PMSM Rotor Position Estimator. Based on Virtual HF Injection Method (VHFIM), In proc. EPE '05, September 2005, Dresden [0014]

Claims (25)

Device for determining the position of the rotor of electrical machines, which are provided with a stator in addition to the rotor, at least consisting of a power unit ( 3 ) with power electronic actuators ( 51 . 52 ), from an arrangement ( 50 ) for controlling the power unit ( 3 ) and from a higher-level control unit ( 5 ), characterized in that an evaluation unit ( 9 . 33 ) is introduced for the detection / determination of the current flow direction, which via one or more lines ( 28 . 29 . 32 ) or via interface lines ( 57 ) of the higher-level control unit ( 5 ) provides the information about the current flow direction sign (I) permanently available. Device for determining positions of a rotor in electrical machines ( 2 ), which is provided next to the rotor with a stator, comprising at least - a power unit ( 3 ) with power electronic actuators ( 51 . 52 ), which are connected to the rotor, - an arrangement for driving the power electronic actuators, - a measuring device ( 55 ), which provides signals, - a higher-level control unit ( 5 ) for controlling the electrical machine ( 2 ), characterized in that the measuring device ( 55 ) provides a signal at which the current flow direction sign (I) can be detected, and the arrangement for detecting / determining the current flow direction sign (I) an evaluation unit ( 9 ) for evaluation by the measuring device ( 55 ) signal to determine the current flow direction sign (I) in the rotor of the machine ( 2 ) contains. Device according to claim 1 or 2, characterized in that the evaluation unit ( 9 ) for determining the direction of current flow between the measuring device ( 55 ) and power unit ( 3 ) is connected and at least contains and at least comprises - on the input side four arranged flip-flops ( 10 . 11 . 12 . 13 ), - two of the flip-flops ( 10 . 11 . 12 . 13 ) downstream, OR elements ( 21 . 22 ) and, on the output side, the OR elements ( 21 . 22 ) downstream XOR element ( 27 ). Device according to claim 1 or 2, characterized in that the components of the evaluation unit ( 9 ) are interconnected in such a way that from the output lines ( 14 . 15 ) of the arrangement for the detection of the beginning of the commutation and the end of the commutation (measuring device ( 55 ) to the first flip-flop ( 10 ) and the second flip-flop ( 11 ) the output lines ( 14 ), while at the third flip-flop ( 12 ) and the fourth flip-flop ( 13 ) the output line ( 15 ), wherein to the RESET inputs R of the four parallel flip-flops ( 10 . 11 . 12 . 13 ) Cables ( 16 . 17 . 18 . 19 ) leading to the PWM signals leading output line ( 20 ) and with the PWM signal from the higher-level control unit ( 5 ), the first flip-flop ( 10 ) and the fourth flip-flop ( 13 ) the OR gate ( 21 ) and the second flip-flop ( 11 ) and the third flip-flop ( 13 ) the second OR gate ( 22 ) is connected downstream of the output Q of the first flip-flop ( 10 ) a signal line ( 23 ) to one of the inputs of the first OR gate ( 21 ) for transmitting the freewheel signal FRW_LS_H, wherein the output Q of the fourth flip-flop ( 13 ) a signal line ( 24 ) to the other input of the first OR gate ( 21 ) is conducted to transmit the freewheel signal FRW_LS_L, wherein the output Q of the second flip-flop ( 11 ) a signal line ( 25 ) to one of the inputs of the second OR gate ( 22 ) for transmitting the freewheel signal FRW_HS_L, wherein the output Q of the third flip-flop ( 12 ) a signal line ( 26 ) to the second input of the second OR gate ( 22 ) for transmitting the freewheeling signal FRW_HS_H, wherein the output of the first OR gate ( 21 ) a signal line ( 28 ) to the higher-level control unit ( 5 ), on which the freewheel signal FRW_LS is transmitted, and from the output of the second OR gate ( 22 ) a signal line ( 29 ) to the higher-level control unit ( 5 ), on which the freewheel signal FRW_HS is transmitted, are guided, wherein a first branch line ( 30 ) of the signal line ( 28 ) to the first input of the XOR gate ( 27 ) and a second branch line ( 31 ) of the signal line ( 29 ) to the second input of the XOR gate ( 27 ), wherein the XOR element ( 27 ) a signal line ( 32 ) to the higher-order signal line ( 5 ), on which the confirmation signal "valid" is transmitted. Device according to claim 1 or 2, characterized in that the at least one rotor having electric machine ( 2 ) is a BLDC motor or a permanent magnet synchronous machine. Device according to claim 1 or 2, characterized in that the measuring device ( 55 ) two comparators ( 7 . 8th ) containing the voltage at the upper measuring point MP with a positive Compare reference voltage and a negative reference voltage, wherein the output didt_p indicate a positive current change and the output didt_n a negative current change at the relevant switching edge. Device according to claim 1 or 2, characterized in that the evaluation unit ( 9 ) the output signal FRW_LS indicates that the current flow direction from the motor ( 2 ) in the phase connection of the power unit ( 3 ), wherein the output signal FRW_HS indicates that the current flow direction from the power unit ( 3 ) in the engine ( 2 ) and the output signal "valid" indicates that the output of the evaluation unit ( 9 . 33 ) correct is. Device according to claim 1 or 2, characterized in that the evaluation unit ( 9 ) is contained in a system for motor control, which consists of the known arrangement, which is described in the document DE 10 2008 026 499 A1, wherein additionally in a central control unit ( 53 ) the order ( 9 ), the output of this module being connected via one or more separate lines ( 28 . 29 . 32 ) to the higher-level control unit ( 5 ) and the method for synchronizing the position in the higher-level control unit ( 5 ) is performed. Device according to claim 1 or 2, characterized in that the information about the current direction in the phase terminals instead of via separate lines via the existing interface ( 56 ) from the evaluation unit ( 9 ) to the higher-level control unit ( 5 ) is transmitted. Device according to claim 1 or 2, characterized in that the evaluation units ( 9 . 33 ) in a conventional system for driving BLDC motors and permanent magnet synchronous machines ( 2 ) are integrated according to the prior art, wherein the output of the evaluation unit ( 9 . 33 ) via a line with the higher-level control unit ( 5 ) and provides the information about the direction of current flow in the phase terminals. Device according to claim 1, characterized in that at extremely low load current, the current change in the inductance ( 54 ) on the switching edges is not sufficient for the comparators ( 7 . 8th ) reliably, wherein the output signal "valid" changes to low level and another possibility of determining the sign sign (I) of the current I _MOT (t) or another type of detection of positions of a rotor triggers. Device according to claim 1, characterized in that in an evaluation unit ( 33 ) is detected for current direction detection for low load currents freewheeling at the power electronic actuator to the negative supply voltage, wherein the function of the evaluation unit ( 33 ) a small dead time when switching the power electronic actuators ( 51 . 52 ), within which dead time a comparator unit ( 34 ) compares the phase voltage U _PH (t) with a low negative voltage, wherein a reset signal R the flip-flop ( 37 ) resets at the beginning of each switching edge, and when a freewheel on the power electronic actuator ( 51 . 52 ) to the negative supply voltage (-0.2 V), the flip-flop ( 37 ) set. Device according to claim 12, characterized in that an edge detector arrangement ( 40 ) at least comprises: - a negator ( 41 ) and - an XOR element ( 42 ), via its output line ( 43 ) the signal R leads to the reset of the flip-flop on each edge, which produces a short pulse on each incoming edge. Device according to claim 12 or 13, characterized in that a further comparator unit, in which the phase voltage U _{PH is} compared with a positive supply voltage or a reference voltage, is provided. Device according to claim 1 or 2, characterized in that the arrangement ( 9 ) for detecting the current flow direction, the output signals of a measuring device ( 55 ) which evaluates the voltage at an inductance for measuring the current change in the power unit ( 3 ) compares with at least one reference voltage. Device according to claim 1 or 2, characterized in that the arrangement ( 9 ) for detecting the current flow direction, the sign of the voltage at an inductance ( 54 ) in the power section ( 3 ) evaluates. Device according to at least one of the preceding claims, characterized in that the evaluation in the arrangement for detecting the direction of current flow respectively takes place on switching edges. Device according to claim 1 or 2, characterized in that the arrangement ( 9 ) For detecting the current flow direction within a freewheeling time / dead time compares the phase voltage U _PH (t) with a reference voltage below the negative supply voltage and the result buffered until at least the next switching edge. Device according to claim 1 or 2, characterized in that the arrangement ( 9 ) For detecting the current flow direction within a freewheeling time / dead time compares the phase voltage U _PH with a reference voltage above the positive supply voltage and the result buffered until at least the next switching edge. Device according to claim 1, characterized in that the arrangement ( 9 ) for detecting the direction of current flow in a device according to DE 10 2008 026 499 A1 or DE 10 2008 026 500 A1 and the measuring device already present there ( 55 ) is used to detect the beginning of the commutation and the end of the commutation to obtain the information about the current flow direction. Method for determining the position of the rotor of electric machines ( 2 ), with a device according to claims 1 to 20, consisting at least of the machine ( 2 ) with at least one rotor and a stator, with a power unit ( 3 ) with power electronic actuators ( 51 . 52 ), with an arrangement ( 50 ) for controlling the power unit ( 3 ) and with a higher-level control unit ( 5 ), characterized in that the generation of the drive signals for the electric machine ( 2 ) takes place such that the reversal of the current flow direction takes place in at least one phase at a certain time within the generation of the output average phase voltage U _PH . A method according to claim 21, characterized in that the target time for the reversal of the current flow direction of the sign change ± sign (I) of the mean drive voltage of the relevant phase or the achievement of the average drive voltage of half positive supply voltage. A method according to claim 21, characterized in that the target time for the reversal of the current flow direction is a constant time before the zero crossing or after the zero crossing of the average phase voltage or the achievement of the average phase voltage U _PH of half the positive supply voltage. A method according to claim 21, characterized in that the target time for the reversal of the current flow direction is given by a constant phase shift relative to the zero crossing of the average phase voltage or the achievement of the average phase voltage U _PH of half positive supply voltage. Method according to at least one of claims 23 or 24, characterized in that the phase shift or time difference is varied as a function of the detected position of the rotor in order to avoid geometric inaccuracies of the machine ( 2 ) to compensate.

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