DE102012012762B4 - Device for determining positions of a rotor in electrical machines - Google Patents

Abstract

Device (1) for determining positions of a rotor in electric machines (2), which are provided with a stator in addition to the rotor, comprising at least - a power part (3) with power electronic actuators (51, 52) connected to the rotor , - an arrangement (50) for controlling the power electronic actuators (51, 52) of the power section (3), - a measuring device (55) which provides signals, - a higher-level control unit (5) for controlling the electric machine (2 ), wherein the measuring device (55) is connected to a measuring inductance (54) located in the power section (3) and provides a signal at which a current flow direction sign (I) can be detected, and the arrangement (50) has an evaluation unit (50). 9) for determining the current flow direction sign (I), in which an evaluation of the by the measuring device (55) transmitted signal for determining the current flow direction sign (I) in the rotor the machine (2) is performed, wherein the evaluation unit (9) for detecting the current flow direction sign (I) between the measuring device (55) and power section (3) is connected and at least on the input side four arranged flip-flops (10, 11, 12 , 13), - two flip-flops (10, 11, 12, 13) downstream, arranged in parallel OR gates (21, 22) and - the output side of the OR gates (21, 22) downstream XOR gate (27 ), as well as via a line or multiple lines (28, 29, 32) or via interface lines (57) the parent control unit (5) the information about the current flow direction sign (I) permanently provides and the sign of the voltage at the measuring inductance ( 54) in the power section (3), wherein the measuring device (55) includes two comparators (7, 8) which compare the voltage at the upper measuring point MP with a positive reference voltage and a negative reference voltage, wherein an output didt_p a positive current change and an output didt_n indicate a negative current change at a respective switching edge.

Description

The invention relates to a device for determining positions of a rotor in electric 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 Maschine 2 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 that directly with the machine 2 communicates
• - 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 described in the publication AVR443: Sensor-based conrol of three-phase brushless DC motor, at the Internet address http://www.atmel.com/Images/doc2596.pdf dated February 2006. 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 general conditions is described in the publication AVR444: Sensorless control of 3-phase brushless DC motors, at the Internet address http://www.atmel.com/Images/doc8012.pdf dated October 2005. 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 control of a motor are in the publication Perassi: Field-oriented control of the permanent-magnet synchronous machine without position sensor for the entire speed range up to Standstill, under 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 A1 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.

A device and a method for rotor position determination is described in the publication Dobrucky, Filka, Spanik, Zigmund: Real-Time PMSM Rotor Position Estimator Based on Virtual RF 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.

• – wenigstens eine Phasendetektorschaltung zum Abtasten des Vorzeichens eines Stromes/mehrerer Ströme, wobei das Vorzeichen des Stromes zur Feststellung eines Nulldurchgangs des Stroms verwendet wird,
• – einen Interpolator zum Empfangen einer Spannungsreferenz und zum Ausgeben einer Frequenzreferenz und einer Phasenverschiebungsreferenz, wobei die Phasenverschiebungsreferenz ein Unterschied zwischen einer erzwungenen Spannungsmodulation und dem einen Strom/mehreren Strömen ist, und
• – eine Reglerschaltung zur Verwendung eines Fehlers zwischen der Phasenverschiebungsreferenz und dem Vorzeichen des einen Stromes/der mehreren Ströme zur Berechnung einer Phasenverschiebungskompensation, wobei das Vorzeichen des einen Stromes/der mehreren Ströme bei ersten Vorzeichenwechselvorgängen als positiv festgestellt wird, wenn eine Sinuswelle des Stromes in einen positiven Bereich übergeht, wobei die ersten und die zweiten Vorzeichenwechselvorgänge zur Feststellung einer Phasenverschiebung des Stromes gegenüber der erzwungenen Spannungsmodulation verwendet werden.

The publication DE 11 2007 000 833 T5 relates to a circuit for using the sign changes of a motor phase and the back EMF currents of a motor phase for controlling PWM. The object is to perform a determination of the sign of a current when a sine wave of the current crosses zero and the use of sign change (at zero crossing) to detect a phase shift of the current versus a forced voltage modulation. The circuit is intended to optimize a power transferred from an inverter circuit to a motor, the circuit using a control method for starting the motor to bring it to a minimum speed, and receiving each phase of the motor from the inverter circuit, the circuit comprising :

• At least one phase detector circuit for sampling the sign of a current (s), the sign of the current being used to detect a zero crossing of the current,
• An interpolator for receiving a voltage reference and outputting a frequency reference and a phase shift reference, wherein the phase shift reference is a difference between a forced voltage modulation and the one current (s), and
• A regulator circuit for using an error between the phase shift reference and the sign of the one stream (s) to calculate a phase shift compensation, wherein the sign of the one stream (s) is positively detected at first sign swaps when a sine wave of the stream into one positive range, using the first and second sign changes to detect a phase shift of the current versus forced voltage modulation.

The publication DE 11 2007 000 833 T5 describes a method for commutation of brushless DC motors or PMSM (permanent magnet synchronous machines), the method being represented in the form of functional block images. Although the prior art method is usually completely solved with software, the method is disclosed in the document DE 11 2007 000 833 T5 described and designated as a circuit. The method uses the information about the time of the current direction change. The detection of the current direction or the change of the current direction is in the document DE 11 2007 00 833 T5 but not stated.

• 1. Es tritt eine Verfälschung des ausgegebenen tatsächlichen Tastverhältnisses gegenüber dem gewünschten Tastverhältnis auf. Das führt besonders bei sinusförmiger Ansteuerung der Maschine zu verringerter Performance.
• 2. Ein weiterer Nachteil ist die Erhöhung der Verluste im Leistungsteil durch die Totzeit.
• 3. Ein weiteres Problem stellen unerwünschte Schwingungen dar, die bei Verwendung einer totzeitbehafteten Ansteuerung in Verbindung mit steilen Schaltflanken zur Verringerung der Schaltverluste in den Leistungsbauelementen auftreten.

Another printed font DE 11 2007 000 833 T5 concerns a switching node based, sensorless motor control for a PM motor. It is used to measure the sign of a current flowing into an inverter stage which is coupled to a phase of a motor and induced by a back EMF (electromotive force) in a winding of the phase of the motor, the inverter stage is connected between a power supply and ground, the circuit comprising a gate drive circuit coupled to the inverter stage for alternately connecting the phase of the motor to the power supply and the ground, the gate Driver circuit comprises a current waveform detection circuit, wherein the current waveform detection circuit measures the signs of the current flowing in the inverter stage to control the commutation of switches in the inverter stage. The object is to compare the voltage of a half-bridge arm of the inverter with a threshold value and to provide an output signal which varies in accordance with the comparison result. When used in a motor drive system driving the motor, the sign of the current is measured, ie, the direction or course of the current flowing in or out of a sensorless motor control motor. In the publication DE 11 2007 000 429 T5 an arrangement for measuring the current direction during the dead time is given. For this purpose, however, a sufficiently large dead time in the operation of the half-bridges is necessary. This big dead time has some disadvantages:

• 1. There is a corruption of the output actual duty ratio to the desired duty ratio. This leads to reduced performance, especially with sinusoidal control of the machine.
• 2. Another disadvantage is the increase in losses in the power unit due to the dead time.
• 3. Another problem is unwanted vibrations that occur when using a dead-time control in conjunction with steep switching edges to reduce switching losses in the power components.

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.

• – 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.

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, the drive circuit having a upstream programming and control unit is connected upstream. At least two actively switching actuators are connected by the control signal lines to the drive circuit, 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 the higher-level programming and control unit generates, wherein 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 superordinate programming and control unit by means of at least one signal line of the control interface 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 detection of the time of the end of the commutation are 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 for determining positions of a rotor in electrical machines, which is designed so suitable that the direction of current flow determined in the individual phases of the rotor of the electric machine and evaluated by the parent control unit can as well as that a sinusoidal control of the electrical machines is allowed, without generating a high additional hardware cost.

• – ein Leistungsteil mit leistungselektronischen Stellgliedern, die an den Rotor angeschlossen sind,
• – eine Anordnung zum Ansteuern der leistungselektronischen Stellglieder des Leistungsteils,
• – eine Messeinrichtung, die Signale zur Verfügung stellt,
• – eine übergeordnete Steuereinheit zur Ansteuerung der elektrischen Maschine, wobei die Messeinrichtung mit einer im Leistungsteil befindlichen Messinduktivität verbunden ist und ein Signal zur Verfügung stellt, an dem eine Stromflussrichtung sign(I) festgestellt werden kann, und die Anordnung eine Auswerteeinheit zur Feststellung der Stromflussrichtung sign(I) enthält, in der eine Auswertung des von der Messeinrichtung übermittelten Signals zur Feststellung der Stromflussrichtung sign(I) im Rotor der Maschine durchgeführt wird, wobei die Auswerteeinheit zur Feststellung der Stromflussrichtung sign(I) zwischen Messeinrichtung und Leistungsteil geschaltet ist und zumindest enthält
• – eingangsseitig vier angeordnete Flip-Flops,
• – zwei den Flip-Flops nachgeordnete, parallel angeordnete ODER-Glieder und
• – ausgangsseitig ein den ODER-Gliedern nachgeschaltetes XOR-Glied, sowie über eine Leitung oder mehrere Leitungen oder über Interfaceleitungen der übergeordneten Steuereinheit die Information über die Stromflussrichtung sign(I) permanent zur Verfügung stellt und das Vorzeichen der Spannung an der Messinduktivität im Leistungsteil auswertet, wobei die Messeinrichtung zwei Komparatoren enthält, die die Spannung am oberen Messpunkt MP mit einer positiven Referenzspannung und einer negativen Referenzspannung vergleichen, wobei ein Ausgangssignal didt_p eine positive Stromänderung und ein Ausgangssignal didt_n eine negative Stromänderung an einer betreffenden Schaltflanke anzeigen.

The object is solved by the features of patent claim 1. The device for determining positions of a rotor in electric machines, which are 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 of the power unit,
• - a measuring device that provides signals,
• A higher-order control unit for controlling the electrical machine, wherein the measuring device is connected to a measuring inductance located in the power unit and provides a signal at which a current flow direction sign (I) can be detected, and the arrangement comprises an evaluation unit for determining the current flow direction sign (I), in which an evaluation of the signal transmitted by the measuring device for determining the current flow direction sign (I) is performed in the rotor of the machine, wherein the evaluation unit for determining the current flow direction sign (I) between the measuring device and power unit is connected and at least contains
• On the input side four arranged flip-flops,
• - Two downstream of the flip-flops, arranged in parallel OR gates and
• On the output side, an XOR element connected downstream of the OR elements, as well as permanently providing the information about the current flow direction sign (I) via a line or several lines or via interface lines of the higher-order control unit and evaluating the sign of the voltage at the measuring inductance in the power section, wherein the measuring means includes two comparators which compare the voltage at the upper measuring point MP with a positive reference voltage and a negative reference voltage, wherein an output signal didt_p indicate a positive current change and an output signal didt_n a negative current change at a respective switching edge.

The components of the evaluation unit can be interconnected in such a way
in that the first output line is routed from the output lines of the measuring device for detecting the current commutation from the beginning of the commutation and the end of the commutation to the first flip-flop and the second flip-flop, while to the third flip-flop and the fourth flip-flop the second output line is guided,
wherein the RESET inputs R of the four parallel flip-flops lines are performed, the are connected to the PWM signals leading output line and which are operated with the PWM signal from the higher-level 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 evaluation unit indicates the output signal FRW_LS 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 is correct is.

The evaluation unit may be contained in a system for controlling the motor with a central control unit, the system consisting of the conventional device for direct commutation between series-connected power electronic actuators in a circuit breaker arrangement with inductive load, in addition in the central control unit, the evaluation unit is inserted, wherein the output of this module is guided via one or more separate lines to the higher-level control unit and a synchronization of the position in the higher-level control unit is executed.

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

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

The evaluation unit for detecting the direction of current flow can be incorporated in a conventional device for direct commutation between series-connected power electronic actuators in a circuit breaker arrangement with inductive load or in a conventional device for controlling the Kommutierungsgeschwindigkeit between series-connected power electronic actuators with inductive load and there already use existing measuring device for detecting the current commutation from the beginning of the commutation and end of the commutation to obtain the information about the current flow direction.

The mode of operation consists in that the generation of the drive signals for the electric machine takes place in such a way that the reversal of the current flow direction takes place in at least one phase 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 middle phase voltage or reaching the average phase voltage U _PH 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 compensate for geometric inaccuracies of the machine.

For position detection, the sign of the current I _MOT (t) is applied to at least one phase of the rotor of the machine (FIG. 2 ) and the sign change is synchronized with the time course of the generated phase voltage U _PH (t).

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

Show it:

1 a structure of a device for controlling an electric machine, for. B. for brushless DC motors (BLDC motors) or permanent magnet synchronous machines (PMSM) or synchronous machines in general according to the prior art,

2 an arrangement for reducing the noise radiation in a device for direct commutation between series-connected power electronic actuators according to the prior art,

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 device 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,

7 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

8th 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 _emf (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 sign sign (I) of the phase current I _PH (t) is evaluated and the instant t _{W of} the sign change ± sign (I) of the phase current I _MOT (t) is brought into accordance with the time characteristic 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) 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.

Dazu wird die Frequenz der generierten Phasenspannung U_PH(t) entweder verringert oder erhöht, so dass im stationären Zustand der Vorzeichenwechsel ±sign(I) des Phasenstroms I_MOT(t) vorzugsweise gleichzeitig mit dem Vorzeichenwechsel ±sign(I) der Phasenspannung U_PH(t) auftritt. Die Messung kann z. B. einmal pro einer elektrischen Umdrehung des Rotors oder bis zu sechsmal pro einer elektrischen Umdrehung des Rotors oder noch seltener durchgeführt werden. Je häufiger die Auswertung des Vorzeichenwechsels ±sign(I) stattfindet, desto schneller kann das Verfahren auf Drehzahländerungen oder Laständerungen des Rotors reagieren. Je seltener die Auswertung stattfindet, desto geringer ist die Anforderung an die Prozessierungsgeschwindigkeit der Einrichtung 1 zur Steuerung für den Motor 2.It is the goal to synchronize the sign change from + sign (I) to -sign (I) or vice versa, in the following, sign (I), of the current I _MOT (t) with the output phase voltage U _PH (t). 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) and, depending on the position within the generation of the phase voltage U _PH (t), a corrective intervention in the generation of the phase voltage U _PH (t) is also made there.

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.

In the 7 and 8th illustrated device for an electrical 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.

• – 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.

Most of the mentioned units are already contained in known devices for driving, but do not contain any detection of positions of a rotor. 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 use of the device proposed here, if one of the devices 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 to be measured to the negative supply voltage. 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 passed, wherein 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 be served, the first flip-flop 10 and the fourth flip-flop 13 the OR gate 21 is connected downstream and the second flip-flop 11 and the third flip-flop 13 the second OR gate 22 is followed, wherein 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 is performed, wherein 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, wherein the output Q of the second flip-flop 11 a signal line 25 to one of the entrances of the second OR gate 22 for the transmission of the freewheel signal FRW_HS_L is performed, 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 freewheel signal FRW_HS_H is performed, 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 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, wherein the XOR element 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" may change to low level and another possibility of determining the sign sign (I) of the current or another way of detecting positions of a rotor is necessary.

A preferred form of implementation of the presented device in a motor control system is in 7 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.

Synchronization of 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 8th 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

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

Claims (8)

Facility ( 1 ) for determining positions of a rotor in electrical machines ( 2 ), which are provided next to the rotor with a stator, comprising at least - a power unit ( 3 ) with power electronic actuators ( 51 . 52 ) connected to the rotor, - an arrangement ( 50 ) for driving the power electronic actuators ( 51 . 52 ) of the power section ( 3 ), - a measuring device ( 55 ), which provides signals, - a higher-level control unit ( 5 ) for controlling the electrical machine ( 2 ), the measuring device ( 55 ) with one in the power unit ( 3 ) measuring inductance ( 54 ) and provides a signal at which a current flow direction sign (I) can be detected, and the arrangement ( 50 ) an evaluation unit ( 9 ) for determining the current flow direction sign (I), in which an evaluation of the by the measuring device ( 55 ) transmitted signal for determining the current flow direction sign (I) in the rotor of the machine ( 2 ), the evaluation unit ( 9 ) for determining the current flow direction sign (I) between the measuring device ( 55 ) and power unit ( 3 ) and at least contains - 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 ), as well as via one or more wires ( 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 and the sign of the voltage at the measuring inductance ( 54 ) in the power section ( 3 ), whereby the measuring device ( 55 ) two comparators ( 7 . 8th ) comparing the voltage at the upper measurement point MP with a positive reference voltage and a negative reference voltage, wherein an output signal didt_p indicates a positive current change and an output signal didt_n a negative current change at a respective switching edge. Device according to claim 1, 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 measuring device ( 55 ) for the detection of the current commutation from the beginning of the commutation and the end of the commutation to the first flip-flop ( 10 ) and the second flip-flop ( 11 ) the first output line ( 14 ), while to the third flip-flop ( 12 ) and the fourth flip-flop ( 13 ) the second 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 Limb ( 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 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 ) correct is. Device according to claim 1, characterized in that the evaluation unit ( 9 ) in a motor control system with a central control unit ( 53 ), the system consisting of the conventional device for direct commutation between series-connected power electronic actuators in an inductive load circuit breaker arrangement, in addition in the central control unit ( 53 ) the evaluation unit ( 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 a synchronization of the position in the higher-level control unit ( 5 ) is performed. Device according to claim 1, 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 claims 1 to 5, characterized in that the evaluation unit ( 9 ) in a conventional system for driving BLDC motors and permanent magnet synchronous machines ( 2 ), the output of the evaluation unit ( 9 ) 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 measuring 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 the evaluation unit ( 9 ) for detecting the direction of current flow in a conventional device for direct commutation between series-connected power electronic actuators in a circuit breaker arrangement with inductive load or in a conventional device for controlling the commutation speed between series-connected power electronic actuators with inductive load is introduced and there already existing measuring device ( 55 ) is used for detecting the current commutation from the beginning of the commutation and the end of the commutation to obtain the information about the current flow direction.

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