EP3834279A1 - Space vector modulation method taking into account minimum switching status times for controlling a multi-phase electric machine - Google Patents
Space vector modulation method taking into account minimum switching status times for controlling a multi-phase electric machineInfo
- Publication number
- EP3834279A1 EP3834279A1 EP19801679.2A EP19801679A EP3834279A1 EP 3834279 A1 EP3834279 A1 EP 3834279A1 EP 19801679 A EP19801679 A EP 19801679A EP 3834279 A1 EP3834279 A1 EP 3834279A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- space pointer
- pointer
- pulse period
- space
- electrical machine
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
- H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
- H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
- H02M7/53871—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
- H02M7/53875—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current with analogue control of three-phase output
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters
- H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters with pulse width modulation
- H02P27/085—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters with pulse width modulation wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
- H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
- H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
- H02M7/53871—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
- H02M7/53875—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current with analogue control of three-phase output
- H02M7/53876—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current with analogue control of three-phase output based on synthesising a desired voltage vector via the selection of appropriate fundamental voltage vectors, and corresponding dwelling times
Definitions
- the invention relates to a method and a power converter for controlling a multiphase electrical machine, each phase voltage of the electrical machine having two
- Space vector modulation can be controlled.
- each switching state is the
- a target space pointer is specified for successive pulse periods of the space modulation.
- the target space pointer is implemented according to the principle of pulse width modulation by changing the basic voltage space pointer within the respective pulse period as a time average over the pulse period.
- connection terminals of an electrical machine controlled in this way with a room modulation he will experience elevated voltages if two of the half bridges are switched simultaneously or almost simultaneously in opposite directions to one another. Therefore, the space vector modulation is usually realized in such a way that a simultaneous one to the other
- US 9 608 545 B1 discloses a method for driving a
- US 5 955 862 A discloses a frequency converter for an asynchronous motor with a voltage converter which has switches controlled according to pulse width modulation. If at least one of two components of an output voltage vector is smaller than a predetermined minimum value, two substitute vectors are calculated, the vector mean of which is equal to the output voltage vector, the components of a first substitute vector each being larger than the minimum value.
- the substitute vectors are used, for example, in two halves of a pulse period or in two successive pulse periods of the pulse width modulation.
- the invention has for its object to ben a method and an apparatus for improved control of a multi-phase electrical machine with space vector modulation.
- the object is achieved according to the invention by a method having the features of claim 1 and a power converter having the features of claim 11.
- each phase voltage of the electrical machine is generated with two electronic switches connected to form a half bridge, and the switching states of the half bridges are controlled with space vector modulation.
- a minimum dwell time is specified and each of them is active Switching state of the half-bridges represented by the basic voltage space pointer is maintained at least for the minimum dwell time.
- the minimum dwell time prevents the time duration of a switching state represented by an active basic voltage space vector from becoming so short that the before and Switching states set after this switching state follow one another almost instantaneously, whereby an almost simultaneous, similar switching of two half-bridges can be generated. Avoiding such a switching of the half-bridges reduces a conductor-earth voltage load on the electrical machine. As a result, the insulation strength of the electrical machine can be dimensioned lower and the electrical machine can be better utilized by using less insulation material in the grooves through which the coil windings of the electrical machine run, and this space is used for the coil windings.
- the invention further provides that for each pulse period of the space vector modulation a target space pointer is specified for a switching state average of the switching states of the half bridges averaged over the pulse period, and that if the switching state means represented by the target space pointer cannot be realized, a switching state value is set , which is represented by a spare room pointer that deviates slightly from the target room pointer.
- the space pointer amount of the replacement room pointer coincides with the space pointer amount of the target space pointer and the space pointer angle of the replacement space pointer differs as little as possible from the space pointer angle of the target space pointer.
- a time period is shortened in which the switching state of the half bridges is represented by one of the active basic voltage space vector within the pulse period.
- the duration of the active basic voltage space vector that would be used longest within the pulse period to implement the desired space vector is preferably shortened.
- the aforementioned embodiments of the invention take into account the fact that, due to the minimum dwell time specified for active basic voltage space pointers, not every switching state mean value represented by a target space pointer can be realized. In the case of a not realizable target space pointer, the invention therefore provides instead of the target space pointer to realize a spare room pointer that deviates only slightly from the target room pointer.
- the invention also provides that a Differenzraumzei ger is formed between the target space pointer and the spare space pointer of a pulse period and the target space pointer of the pulse period following the pulse period is modified as a function of the difference space pointer compared to a target space pointer originally predetermined for the following pulse period.
- the target space pointer of a pulse period is determined by the difference space pointer of the previous one
- the target space pointer of a pulse period is modified by the difference space pointer of the previous pulse period, in that the difference space pointer is rotated by a difference angle between the space pointer angle of the target space pointer originally specified for the pulse period and the space pointer angle of the target space pointer of the previous pulse period and the rotated difference space pointer to that nominal space pointer originally specified for the pulse period is added.
- the aforementioned embodiments of the invention make it possible to compensate for a setpoint deviation of a voltage-time area, which is caused in one pulse period by using a replacement space pointer instead of the setpoint pointer, in a subsequent pulse period by the setpoint pointer of the following pulse period depending on the Deviation of the spare room pointer from the target room pointer is modified.
- a further embodiment of the invention provides that at least twice a time period between a switching state change of a switching state of the half-bridges and the phase voltage change of the phase voltages of the electrical machine generated by the switching state change is specified as the minimum dwell time. That period is For example, a signal runtime of a signal in a connecting cable that connects the electrical machine to a converter having the half-bridges.
- the reciprocal of a resonance frequency dependent on a longitudinal inductance and a winding capacitance of the electrical machine is used as the minimum dwell time
- the two aforementioned configurations of the invention advantageously adapt the minimum dwell time to the physical properties of the electrical machine and their coupling to the half-bridges.
- the adaptation of the minimum dwell time to the resonance frequency of the electrical machine has the particular advantage that it can also reduce a voltage load at a star point of the electrical machine.
- Another embodiment of the invention provides that two consecutive switching states of the half bridges differ from one another only by the switch positions of exactly one half bridge. This advantageously avoids stresses caused by simultaneous switching of two or more half bridges.
- a further embodiment of the invention provides that a minimum switch position time is specified and a switch position of each half bridge is maintained at least for the minimum switch position position. This advantageously avoids stress loads caused by rapid changes in the phase voltages of individual phases.
- the method according to the invention is only activated if the electrical machine is operated with phase voltages, the amplitudes of which lie in a given voltage range.
- a voltage range is provided for the activation of the method. given in which the electrical machine is exposed to a voltage loading for which it is not designed in a control method with a conventional space vector modulation. With phase voltages outside this voltage range, however, the electrical machine is preferably controlled with a conventional space vector modulation. This takes into account the fact that in the space vector modulation modified according to the invention, a ripple current in the electrical machine increases slightly compared to a conventional space vector modulation, so that the space vector modulation modified according to the invention compared to the conventional space vector modulation only when the voltage loads on the
- Electrical machine is advantageous, for which it is not designed in a control method with a conventional space vector modulation.
- a converter according to the invention for carrying out the method according to the invention comprises, for each phase voltage, two electronic switches connected to form a half bridge and a control unit for controlling the electronic switches according to the method according to the invention.
- the advantages of such a converter correspond to the advantages of the method according to the invention already mentioned above.
- FIG. 1 shows a block diagram of a converter and an electrical machine operated on the converter
- Target space pointer and basic voltage space pointer, 3 shows target space pointers formed in succession according to a first embodiment of the invention
- Pulse periods of a space vector modulation Pulse periods of a space vector modulation.
- FIG. 1 shows a block diagram of a converter 1 and a three-phase electrical machine 3 operated on the converter 1.
- the electrical machine 3 is designed, for example, as a brushless DC motor.
- the converter 1 comprises an output-side inverter ter 4, which has an electrical half-bridge 5, 6, 7 for each phase of the electrical machine 3, in each of which two bridge arms an electronic switch 9, 10 is arranged and the bridge branch with a coil winding of the respective Phase of the electrical machine 3 is connected.
- the converter 1 On the input side, the converter 1 has a rectifier (not shown here) which is connected to the inverter 4 via a DC link (also not shown here).
- Each electronic switch 9, 10 is designed as a MOSFET (metal oxide semiconductor field effect transistor), but can alternatively also be designed, for example, as an IGBT (bipolar transistor with insulated gate electrode). Furthermore, the converter 1 has a control unit 11 for controlling the electronic switches 9, 10 according to the method described in more detail below with reference to FIGS. 2 to 4.
- MOSFET metal oxide semiconductor field effect transistor
- IGBT bipolar transistor with insulated gate electrode
- FIG. 2 shows a section of a room pointer level with a target room pointer 13 and basic voltage space pointers 15, 16,
- Each basic voltage space vector 15, 16, 17 represents a switching state of the half bridges 5, 6, 7, which is indicated by a
- Triple triplet is represented, the three digits each can assume the values 0 or 1 and are each assigned to a half bridge 5, 6, 7.
- the value 1 of a digit of the triple digits represents a switch position of the half-bridge 5, 6, 7 assigned to this number, in which a first electronic switch 9 of the half-bridge 5, 6, 7 is switched on and the second electronic switch 10 is switched off, as a result of which the the half-bridge 5, 6, 7 connected Spu lenwicking of the electrical machine 3 is placed on a positive electrical potential of the DC link of the converter 1.
- the value 0 of a digit of the Zif remote triple stands for a switch position of the half-bridge 5, 6, 7 assigned to this number, in which the first electronic switch 9 of the half-bridge 5, 6, 7 is switched off and the second electronic switch 10 is switched on, as a result of which the with the half bridge 5, 6, 7 connected coil winding of the electrical machine 3 to a negative electrical potential of the DC intermediate circuit of the converter 1 is placed.
- the basic voltage space pointers which represent a switching state, which is represented by one of the number triples 100, 010, 001, 110, 101 or 011, are referred to as active basic voltage space pointers.
- the two basic voltage space pointers, which represent a switching state, which is represented by one of the digit triples 000 or 111, are called passive basic voltage space pointers or
- a set space pointer 13 is specified for an average switching state of the switching states of the half-bridges 5, 6, 7, averaged over the pulse period, with the pulse period between
- the section of the space vector plane shown shows areas whose points represent realizable switching state mean values. These are triangular areas 19, 20 between the active basic voltage space pointers 15 and 16 or 16 and 17, the points represented by the triplets 100, 110, 010 and 000 (or 111), as well as distances 21 to 25, which run between these points. In contrast, the points of a region lying between a triangular surface 19, 20 and the adjacent paths 21 to 25 represent switching average values that cannot be implemented.
- a switching state mean value represented by a point in the triangular area 19 becomes, for example, a temporal switching state sequence 000 100 110 111 110
- a switching state mean value represented by a point on the route 22 is determined, for example, by a change between the switching states 110 and 111 within a Pulse period realized.
- a switching state mean value represented by a point on the route 24 is, for example, by a temporal switching state sequence 100 110
- a target space pointer 13 with the space pointer amount zero is realized by the same over the entire pulse period
- Zero voltage space pointer is set.
- the minimum dwell time is, for example, at least twice a time period between a change in the switching state of a switching state of the half-bridges 5, 6, 7 and the change in phase voltage generated by the change in the switching state of the phase voltages of the electrical machine 3.
- This time period is, for example, a signal running time of a signal in a connecting cable connecting the converter 1 to the electrical machine 3 from the half bridges 5, 6, 7 to connecting terminals of the electrical machine 3.
- the reciprocal of a resonance frequency of the electrical machine 3 which is dependent on a longitudinal inductance and a winding capacitance of the electrical machine 3 is specified as the minimum dwell time.
- a target space pointer 13 which represents a non-realizable switching state mean value, since the switching state 100 would only have to be set for a very short time within a pulse period, so that an almost instantaneous switching state change in the triangular area 19 in accordance with the switching state sequence mentioned above would occur between the switching states 000 and 110 and thus two half-bridges 5, 6, 7 would be switched over almost identically.
- an average switching state value is set, which is represented by a spare space pointer 27 which differs slightly from the target space pointer 13.
- the space pointer amount of the replacement space is correct.
- a period of time is shortened in order to form the spare space vector 27, in which the switching state of the half bridges 5, 6, 7 is represented within the pulse period by one of the active basic voltage space pointers 15, 16, 17.
- the duration of the active basic voltage space vector 15, 16, 17 that would be used longest within the pulse period for realizing the desired space vector 13 is preferably shortened.
- FIGS. 3 and 4 show two different embodiments of the invention, according to which a target space pointer 14 of a pulse period of the space vector modulation is formed if, in the previous pulse period, a replacement space pointer 27 deviating from the target space pointer 13 of the previous pulse period for forming the switching state mean value of the switching states Half bridges 5, 6, 7 was used.
- a difference space pointer 29 is formed between the target space pointer 13 and the spare space pointer 27 of the previous pulse period and the target space pointer 14 is modified by one in the previous pulse period compared to the originally specified target space pointer 14 ′′ depending on the difference space pointer 29 of the previous pulse period to compensate for the deviation of the voltage-time area from its target value caused by the use of the spare space pointer 27 instead of the target space pointer 13.
- the difference space pointer 29 of the preceding pulse period is added to the originally predetermined target space pointer 14 ′′.
- the difference space pointer 29 is moved by a difference angle between the space pointer angle of the target space pointer 14 ′′ originally specified for the pulse period and the space pointer Angle of the target space pointer 13 of the previous pulse period rotated and the rotated differential space pointer 31 is added to the target space pointer 14 "originally specified for the pulse period.
- the method described above with reference to FIGS. 2 to 4 is preferably only activated, for example by means of a parameter for the converter 1, if the electrical machine 3 is operated with phase voltages whose amplitudes are within a predetermined voltage range.
- a voltage range is specified for the activation of the method, in which the electrical machine 3 is exposed to a voltage load for which it is not designed in a control method with a conventional space vector modulation.
- the electrical machine 3 is controlled with a conventional space vector modulation.
- Electrical machine 3 is advantageous, for which it is not designed in a control method with a conventional space vector modulation.
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Abstract
Description
Beschreibung description
RAUMZEIGERMODULATIONSVERFAHREN MIT BERÜCKSICHTIGUNG VON SPACE INDICATOR MODULATION METHOD WITH CONSIDERATION OF
MINDESTSCHALTZUSTANDSZEITEN ZUM STEUEREN EINER MEHRPHASIGEN ELEKTRISCHE MASCHINE MINIMUM SWITCHING TIMES FOR CONTROLLING A MULTI-PHASE ELECTRICAL MACHINE
Die Erfindung betrifft ein Verfahren und einen Stromrichter zum Steuern einer mehrphasigen elektrischen Maschine, wobei jede Phasenspannung der elektrischen Maschine mit zwei zu The invention relates to a method and a power converter for controlling a multiphase electrical machine, each phase voltage of the electrical machine having two
einer Halbbrücke verschalteten elektronischen Schaltern er zeugt wird und die Schaltzustande der Halbbrücken mit einer a half-bridge interconnected electronic switches, it generates and the switching states of the half-bridges with one
Raumzeigermodulation gesteuert werden. Space vector modulation can be controlled.
Bei einer Raumzeigermodulation wird jeder Schaltzustand der With a space vector modulation, each switching state is the
Halbbrücken durch einen Grundspannungsraumzeiger repräsen Represent half bridges through a basic voltage space pointer
tiert und für aufeinander folgende Pulsperioden der Raumzei germodulation wird jeweils ein Sollraumzeiger vorgegeben. Der Sollraumzeiger wird nach dem Prinzip der Pulsweitenmodulation durch einen Wechsel der Grundspannungsraumzeiger innerhalb der jeweiligen Pulsperiode als ein zeitlicher Mittelwert über die Pulsperiode realisiert. A target space pointer is specified for successive pulse periods of the space modulation. The target space pointer is implemented according to the principle of pulse width modulation by changing the basic voltage space pointer within the respective pulse period as a time average over the pulse period.
Zwischen den Anschlussklemmen einer derartig mit einer Raum zeigermodulation gesteuerten elektrischen Maschine treten er höhte Spannungen auf, wenn zwei der Halbbrücken gleichzeitig oder fast gleichzeitig entgegengesetzt zueinander umgeschal tet werden. Deshalb wird die Raumzeigermodulation in der Re gel derart realisiert, dass ein gleichzeitiges zueinander Between the connection terminals of an electrical machine controlled in this way with a room modulation, he will experience elevated voltages if two of the half bridges are switched simultaneously or almost simultaneously in opposite directions to one another. Therefore, the space vector modulation is usually realized in such a way that a simultaneous one to the other
entgegengesetztes Umschalten zweier Halbbrücken vermieden opposite switching of two half bridges avoided
wird. Eine erhöhte Leiter-Erde-Spannung tritt an einer becomes. An increased phase-to-earth voltage occurs at one
elektrischen Maschine jedoch auch auf, wenn zwei Halbbrücken gleichzeitig oder fast gleichzeitig gleichartig umgeschaltet werden . electrical machine, however, also when two half bridges are switched over simultaneously or almost simultaneously in the same way.
US 9 608 545 Bl offenbart ein Verfahren zum Antreiben einer US 9 608 545 B1 discloses a method for driving a
Last, bei dem ein Schaltsignal zum Steuern der Schaltvorgänge von Schalteinrichtungen bereitgestellt wird. Wenn das Schalt signal in eine vorbestimmte Totzone fällt, wird das Schalt signal durch Bewegen eines dem Schaltsignal entsprechenden Load at which a switching signal for controlling the switching processes of switching devices is provided. If the switching signal falls within a predetermined dead zone, the switching signal is obtained by moving one corresponding to the switching signal
Raumzeigers zu einer Grenze der Totzone modifiziert. US 5 955 862 A offenbart einen Frequenzumrichter für einen Asynchronmotor mit einem Spannungsumrichter, der gemäß einer Pulsweitenmodulation gesteuerte Schalter aufweist. Wenn min destens eine von zwei Komponenten eines Ausgangsspannungsvek tors kleiner als ein vorbestimmter Mindestwert ist, werden zwei Ersatzvektoren berechnet, deren vektorieller Mittelwert gleich dem Ausgangsspannungsvektor ist, wobei die Komponenten eines ersten Ersatzvektors jeweils größer als der Mindestwert sind. Die Ersatzvektoren werden beispielsweise in zwei Hälf ten einer Pulsperiode oder in zwei aufeinander folgenden Pulsperioden der Pulsweitenmodulation verwendet. Space pointer modified to a boundary of the dead zone. US 5 955 862 A discloses a frequency converter for an asynchronous motor with a voltage converter which has switches controlled according to pulse width modulation. If at least one of two components of an output voltage vector is smaller than a predetermined minimum value, two substitute vectors are calculated, the vector mean of which is equal to the output voltage vector, the components of a first substitute vector each being larger than the minimum value. The substitute vectors are used, for example, in two halves of a pulse period or in two successive pulse periods of the pulse width modulation.
Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren und eine Vorrichtung zum verbesserten Steuern einer mehrphasigen elektrischen Maschine mit einer Raumzeigermodulation anzuge ben . The invention has for its object to ben a method and an apparatus for improved control of a multi-phase electrical machine with space vector modulation.
Die Aufgabe wird erfindungsgemäß durch ein Verfahren mit den Merkmalen des Anspruchs 1 und einen Stromrichter mit den Merkmalen des Anspruchs 11 gelöst. The object is achieved according to the invention by a method having the features of claim 1 and a power converter having the features of claim 11.
Vorteilhafte Ausgestaltungen der Erfindung sind Gegenstand der Unteransprüche. Advantageous embodiments of the invention are the subject of the dependent claims.
Bei dem erfindungsgemäßen Verfahren zum Steuern einer mehr phasigen elektrischen Maschine wird jede Phasenspannung der elektrischen Maschine mit zwei zu einer Halbbrücke verschal- teten elektronischen Schaltern erzeugt und die Schaltzustände der Halbbrücken werden mit einer Raumzeigermodulation gesteu ert. Dabei wird eine Mindestverweilzeit vorgegeben und jeder von einem aktiven Grundspannungsraumzeiger repräsentierte Schaltzustand der Halbbrücken wird wenigstens für die Min destverweilzeit beibehalten. In the method according to the invention for controlling a multi-phase electrical machine, each phase voltage of the electrical machine is generated with two electronic switches connected to form a half bridge, and the switching states of the half bridges are controlled with space vector modulation. In this case, a minimum dwell time is specified and each of them is active Switching state of the half-bridges represented by the basic voltage space pointer is maintained at least for the minimum dwell time.
Durch die Mindestverweilzeit wird vermieden, dass die Zeit dauer eines von einem aktiven Grundspannungsraumzeiger reprä sentierten Schaltzustands so klein wird, dass die vor und nach diesem Schaltzustand eingestellten Schaltzustande fast instantan aufeinander folgen, wodurch ein fast gleichzeitiges gleichartiges Umschalten zweier Halbbrücken erzeugt werden kann. Durch die Vermeidung eines derartigen Umschaltens der Halbbrücken wird eine Leiter-Erde-Spannungsbelastung der elektrischen Maschine reduziert. Dadurch kann die Isolations festigkeit der elektrischen Maschine niedriger bemessen und die elektrische Maschine besser ausgenutzt werden, indem we niger Isolationsmaterial in die Nuten, durch die Spulenwick lungen der elektrischen Maschine verlaufen, eingebracht wird und dieser Raum für die Spulenwicklungen genutzt wird. The minimum dwell time prevents the time duration of a switching state represented by an active basic voltage space vector from becoming so short that the before and Switching states set after this switching state follow one another almost instantaneously, whereby an almost simultaneous, similar switching of two half-bridges can be generated. Avoiding such a switching of the half-bridges reduces a conductor-earth voltage load on the electrical machine. As a result, the insulation strength of the electrical machine can be dimensioned lower and the electrical machine can be better utilized by using less insulation material in the grooves through which the coil windings of the electrical machine run, and this space is used for the coil windings.
Die Erfindung sieht ferner vor, dass für jede Pulsperiode der Raumzeigermodulation ein Sollraumzeiger für einen über die Pulsperiode gemittelten Schaltzustandsmittelwert der Schalt zustände der Halbbrücken vorgegeben wird, und dass, wenn der von dem Sollraumzeiger repräsentierte Schaltzustandsmittel wert nicht realisiert werden kann, ein Schaltzustandsmittel wert eingestellt wird, der von einem wenig von dem Sollraum zeiger abweichenden Ersatzraumzeiger repräsentiert wird. Bei spielsweise stimmt der Raumzeigerbetrag des Ersatzraumzeigers mit dem Raumzeigerbetrag des Sollraumzeigers überein und der Raumzeigerwinkel des Ersatzraumzeigers weicht möglichst wenig von dem Raumzeigerwinkel des Sollraumzeigers ab. Alternativ wird zur Bildung des Ersatzraumzeigers eine Zeitdauer ver kürzt, in der der Schaltzustand der Halbbrücken innerhalb der Pulsperiode von einem der aktiven Grundspannungsraumzeiger repräsentiert wird. Dabei wird vorzugsweise die Zeitdauer desjenigen aktiven Grundspannungsraumzeigers verkürzt, der am längsten innerhalb der Pulsperiode zur Realisierung des Soll raumzeigers verwendet werden würde. The invention further provides that for each pulse period of the space vector modulation a target space pointer is specified for a switching state average of the switching states of the half bridges averaged over the pulse period, and that if the switching state means represented by the target space pointer cannot be realized, a switching state value is set , which is represented by a spare room pointer that deviates slightly from the target room pointer. For example, the space pointer amount of the replacement room pointer coincides with the space pointer amount of the target space pointer and the space pointer angle of the replacement space pointer differs as little as possible from the space pointer angle of the target space pointer. Alternatively, in order to form the spare space vector, a time period is shortened in which the switching state of the half bridges is represented by one of the active basic voltage space vector within the pulse period. The duration of the active basic voltage space vector that would be used longest within the pulse period to implement the desired space vector is preferably shortened.
Die vorgenannten Ausgestaltungen der Erfindung berücksichti gen, dass infolge der für aktive Grundspannungsraumzeiger vorgegebenen Mindestverweilzeit nicht jeder von einem Soll raumzeiger repräsentierte Schaltzustandsmittelwert realisiert werden kann. Im Falle eines nicht realisierbaren Sollraumzei gers sieht die Erfindung daher vor, statt des Sollraumzeigers einen Ersatzraumzeiger zu realisieren, der nur wenig von dem Sollraumzeiger abweicht. The aforementioned embodiments of the invention take into account the fact that, due to the minimum dwell time specified for active basic voltage space pointers, not every switching state mean value represented by a target space pointer can be realized. In the case of a not realizable target space pointer, the invention therefore provides instead of the target space pointer to realize a spare room pointer that deviates only slightly from the target room pointer.
Die Erfindung sieht außerdem vor, dass ein Differenzraumzei ger zwischen dem Sollraumzeiger und dem Ersatzraumzeiger einer Pulsperiode gebildet wird und der Sollraumzeiger der auf die Pulsperiode folgenden Pulsperiode in Abhängigkeit von dem Differenzraumzeiger gegenüber einem ursprünglich für die folgende Pulsperiode vorgegebenen Sollraumzeiger modifiziert wird. Beispielsweise wird der Sollraumzeiger einer Pulsperio de durch den Differenzraumzeiger der vorhergehenden The invention also provides that a Differenzraumzei ger is formed between the target space pointer and the spare space pointer of a pulse period and the target space pointer of the pulse period following the pulse period is modified as a function of the difference space pointer compared to a target space pointer originally predetermined for the following pulse period. For example, the target space pointer of a pulse period is determined by the difference space pointer of the previous one
Pulsperiode modifiziert, indem der Differenzraumzeiger zu dem ursprünglich für die Pulsperiode vorgegebenen Sollraumzeiger addiert wird. Alternativ wird der Sollraumzeiger einer Puls periode durch den Differenzraumzeiger der vorhergehenden Pulsperiode modifiziert, indem der Differenzraumzeiger um einen Differenzwinkel zwischen dem Raumzeigerwinkel des ur sprünglich für die Pulsperiode vorgegebenen Sollraumzeigers und dem Raumzeigerwinkel des Sollraumzeigers der vorhergehen den Pulsperiode gedreht wird und der gedrehte Differenzraum zeiger zu dem ursprünglich für die Pulsperiode vorgegebenen Sollraumzeiger addiert wird. Modifies the pulse period by adding the difference space pointer to the target space pointer originally specified for the pulse period. Alternatively, the target space pointer of a pulse period is modified by the difference space pointer of the previous pulse period, in that the difference space pointer is rotated by a difference angle between the space pointer angle of the target space pointer originally specified for the pulse period and the space pointer angle of the target space pointer of the previous pulse period and the rotated difference space pointer to that nominal space pointer originally specified for the pulse period is added.
Die vorgenannten Ausgestaltungen der Erfindung ermöglichen, eine Sollwertabweichung einer Spannungs-Zeit-Fläche, die in einer Pulsperiode durch die Verwendung eines Ersatzraumzei gers anstelle des Sollraumzeigers verursacht wird, in einer darauf folgenden Pulsperiode auszugleichen, indem der Soll wertzeiger der folgenden Pulsperiode in Abhängigkeit von der Abweichung des Ersatzraumzeigers von dem Sollraumzeiger modi fiziert wird. The aforementioned embodiments of the invention make it possible to compensate for a setpoint deviation of a voltage-time area, which is caused in one pulse period by using a replacement space pointer instead of the setpoint pointer, in a subsequent pulse period by the setpoint pointer of the following pulse period depending on the Deviation of the spare room pointer from the target room pointer is modified.
Eine weitere Ausgestaltung der Erfindung sieht vor, dass als Mindestverweilzeit mindestens das Doppelte einer Zeitdauer zwischen einer Schaltzustandsänderung eines Schaltzustands der Halbbrücken und der durch die Schaltzustandsänderung er zeugten Phasenspannungsänderung der Phasenspannungen der elektrischen Maschine vorgegeben wird. Diese Zeitdauer ist beispielsweise eine Signallaufzeit eines Signals in einem Verbindungskabel, das die elektrische Maschine mit einem die Halbbrücken aufweisenden Stromrichter verbindet. A further embodiment of the invention provides that at least twice a time period between a switching state change of a switching state of the half-bridges and the phase voltage change of the phase voltages of the electrical machine generated by the switching state change is specified as the minimum dwell time. That period is For example, a signal runtime of a signal in a connecting cable that connects the electrical machine to a converter having the half-bridges.
Alternativ zu der vorgenannten Ausgestaltung der Erfindung wird als Mindestverweilzeit beispielsweise der Kehrwert einer von einer Längsinduktivität und einer Wicklungskapazität der elektrischen Maschine abhängigen Resonanzfrequenz der As an alternative to the aforementioned embodiment of the invention, the reciprocal of a resonance frequency dependent on a longitudinal inductance and a winding capacitance of the electrical machine is used as the minimum dwell time
elektrischen Maschine vorgegeben. specified electrical machine.
Die beiden vorgenannten Ausgestaltungen der Erfindung passen die Mindestverweilzeit vorteilhaft den physikalischen Eigen schaften der elektrischen Maschine und deren Ankopplung an die Halbbrücken an. Die Anpassung der Mindestverweilzeit an die Resonanzfrequenz der elektrischen Maschine hat insbeson dere den Vorteil, dass dadurch auch eine Spannungsbelastung an einem Sternpunkt der elektrischen Maschine gesenkt werden kann . The two aforementioned configurations of the invention advantageously adapt the minimum dwell time to the physical properties of the electrical machine and their coupling to the half-bridges. The adaptation of the minimum dwell time to the resonance frequency of the electrical machine has the particular advantage that it can also reduce a voltage load at a star point of the electrical machine.
Eine weitere Ausgestaltung der Erfindung sieht vor, dass sich je zwei aufeinander folgende Schaltzustände der Halbbrücken nur durch die Schalterstellungen genau einer Halbbrücke von einander unterscheiden. Dadurch werden vorteilhaft Spannungs belastungen durch ein gleichzeitiges Umschalten von zwei oder mehr Halbbrücken vermieden. Another embodiment of the invention provides that two consecutive switching states of the half bridges differ from one another only by the switch positions of exactly one half bridge. This advantageously avoids stresses caused by simultaneous switching of two or more half bridges.
Eine weitere Ausgestaltung der Erfindung sieht vor, dass eine Schalterstellungsmindestzeit vorgegeben wird und eine Schal terstellung jeder Halbbrücke wenigstens für die Schalterstel lungsmindestzeit beibehalten wird. Dadurch werden vorteilhaft Spannungsbelastungen durch schnelle Änderungen der Phasen spannungen einzelner Phasen vermieden. A further embodiment of the invention provides that a minimum switch position time is specified and a switch position of each half bridge is maintained at least for the minimum switch position position. This advantageously avoids stress loads caused by rapid changes in the phase voltages of individual phases.
Bei einer weiteren Ausgestaltung der Erfindung wird das er findungsgemäße Verfahren nur aktiviert, wenn die elektrische Maschine mit Phasenspannungen, deren Amplituden in einem vor gegebenen Spannungsbereich liegen, betrieben wird. Dabei wird für die Aktivierung des Verfahrens ein Spannungsbereich vor- gegeben, in dem die elektrische Maschine einer Spannungsbe lastung ausgesetzt ist, für die sie bei einem Steuerungsver fahren mit einer herkömmlichen Raumzeigermodulation nicht ausgelegt ist. Bei Phasenspannungen außerhalb dieses Span nungsbereiches wird die elektrische Maschine dagegen vorzugs weise mit einer herkömmlichen Raumzeigermodulation gesteuert. Dadurch wird berücksichtigt, dass bei der erfindungsgemäß mo difizierten Raumzeigermodulation ein Rippelstrom in der elektrischen Maschine gegenüber einer herkömmlichen Raumzei germodulation leicht ansteigt, so dass die erfindungsgemäß modifizierte Raumzeigermodulation gegenüber der herkömmlichen Raumzeigermodulation nur bei Spannungsbelastungen der In a further embodiment of the invention, the method according to the invention is only activated if the electrical machine is operated with phase voltages, the amplitudes of which lie in a given voltage range. A voltage range is provided for the activation of the method. given in which the electrical machine is exposed to a voltage loading for which it is not designed in a control method with a conventional space vector modulation. With phase voltages outside this voltage range, however, the electrical machine is preferably controlled with a conventional space vector modulation. This takes into account the fact that in the space vector modulation modified according to the invention, a ripple current in the electrical machine increases slightly compared to a conventional space vector modulation, so that the space vector modulation modified according to the invention compared to the conventional space vector modulation only when the voltage loads on the
elektrischen Maschine vorteilhaft ist, für die sie bei einem Steuerungsverfahren mit einer herkömmlichen Raumzeigermodula tion nicht ausgelegt ist. Electrical machine is advantageous, for which it is not designed in a control method with a conventional space vector modulation.
Ein erfindungsgemäßer Stromrichter zur Durchführung des er findungsgemäßen Verfahrens umfasst für jede Phasenspannung zwei zu einer Halbbrücke verschaltete elektronische Schalter und eine Steuereinheit zur Ansteuerung der elektronischen Schalter gemäß dem erfindungsgemäßen Verfahren. Die Vorteile eines derartigen Stromrichters entsprechen den oben bereits genannten Vorteilen des erfindungsgemäßen Verfahrens. A converter according to the invention for carrying out the method according to the invention comprises, for each phase voltage, two electronic switches connected to form a half bridge and a control unit for controlling the electronic switches according to the method according to the invention. The advantages of such a converter correspond to the advantages of the method according to the invention already mentioned above.
Die oben beschriebenen Eigenschaften, Merkmale und Vorteile dieser Erfindung sowie die Art und Weise, wie diese erreicht werden, werden klarer und deutlicher verständlich im Zusam menhang mit der folgenden Beschreibung von Ausführungsbei spielen, die im Zusammenhang mit den Zeichnungen näher erläu tert werden. Dabei zeigen: The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of exemplary embodiments which will be explained in connection with the drawings. Show:
FIG 1 ein Blockdiagramm eines Stromrichters und einer an dem Stromrichter betriebenen elektrischen Maschine, 1 shows a block diagram of a converter and an electrical machine operated on the converter,
FIG 2 einen Ausschnitt einer Raumzeigerebene mit einem2 shows a section of a room pointer plane with a
Sollraumzeiger und Grundspannungsraumzeigern, FIG 3 gemäß einer ersten Ausführungsvariante der Erfin dung gebildete Sollraumzeiger aufeinander folgender Target space pointer and basic voltage space pointer, 3 shows target space pointers formed in succession according to a first embodiment of the invention
Pulsperioden einer Raumzeigermodulation, Pulse periods of a space vector modulation,
FIG 4 gemäß einer zweiten Ausführungsvariante der Erfin dung gebildete Sollraumzeiger aufeinander folgender 4 shows target space pointers formed in succession according to a second embodiment of the invention
Pulsperioden einer Raumzeigermodulation. Pulse periods of a space vector modulation.
Einander entsprechende Teile sind in den Figuren mit densel ben Bezugszeichen versehen. Corresponding parts are provided in the figures with the same reference numerals.
Figur 1 zeigt ein Blockdiagramm eines Stromrichters 1 und einer an dem Stromrichter 1 betriebenen dreiphasigen elektri schen Maschine 3. Die elektrische Maschine 3 ist beispiels weise als ein bürstenloser Gleichstrommotor ausgebildet. Der Stromrichter 1 umfasst einen ausgangsseitigen Wechselrich ter 4, der für jede Phase der elektrischen Maschine 3 eine elektrische Halbbrücke 5, 6, 7 aufweist, in deren beiden Brückenarmen jeweils ein elektronischer Schalter 9, 10 ange ordnet ist und deren Brückenzweig mit einer Spulenwicklung der jeweiligen Phase der elektrischen Maschine 3 verbunden ist. Eingangsseitig weist der Stromrichter 1 einen (hier nicht dargestellten) Gleichrichter auf, der mit dem Wechsel richter 4 über einen (hier ebenfalls nicht dargestellten) Gleichspannungszwischenkreis verbunden ist. Jeder elektroni sche Schalter 9, 10 ist als ein MOSFET (Metall-Oxid- Halbleiter-Feldeffekttransistor) ausgebildet, kann alternativ aber auch beispielsweise als ein IGBT (Bipolartransistor mit isolierter Gate-Elektrode) ausgebildet sein. Ferner weist der Stromrichter 1 eine Steuereinheit 11 zur Ansteuerung der elektronischen Schalter 9, 10 gemäß dem unten anhand der Fi guren 2 bis 4 näher beschriebenen Verfahren auf. FIG. 1 shows a block diagram of a converter 1 and a three-phase electrical machine 3 operated on the converter 1. The electrical machine 3 is designed, for example, as a brushless DC motor. The converter 1 comprises an output-side inverter ter 4, which has an electrical half-bridge 5, 6, 7 for each phase of the electrical machine 3, in each of which two bridge arms an electronic switch 9, 10 is arranged and the bridge branch with a coil winding of the respective Phase of the electrical machine 3 is connected. On the input side, the converter 1 has a rectifier (not shown here) which is connected to the inverter 4 via a DC link (also not shown here). Each electronic switch 9, 10 is designed as a MOSFET (metal oxide semiconductor field effect transistor), but can alternatively also be designed, for example, as an IGBT (bipolar transistor with insulated gate electrode). Furthermore, the converter 1 has a control unit 11 for controlling the electronic switches 9, 10 according to the method described in more detail below with reference to FIGS. 2 to 4.
Figur 2 zeigt einen Ausschnitt einer Raumzeigerebene mit einem Sollraumzeiger 13 und Grundspannungsraumzeigern 15, 16,FIG. 2 shows a section of a room pointer level with a target room pointer 13 and basic voltage space pointers 15, 16,
17. Jeder Grundspannungsraumzeiger 15, 16, 17 repräsentiert einen Schaltzustand der Halbbrücken 5, 6, 7, der durch ein17. Each basic voltage space vector 15, 16, 17 represents a switching state of the half bridges 5, 6, 7, which is indicated by a
Zifferntripel dargestellt wird, dessen drei Ziffern jeweils die Werte 0 oder 1 annehmen können und jeweils einer Halb brücke 5, 6, 7 zugeordnet sind. Der Wert 1 einer Ziffer des Zifferntripels steht für eine Schalterstellung der dieser Ziffer zugeordneten Halbbrücke 5, 6, 7, bei der ein erster elektronischer Schalter 9 der Halbbrücke 5, 6, 7 eingeschal tet und der zweite elektronische Schalter 10 ausgeschaltet ist, wodurch die mit der Halbbrücke 5, 6, 7 verbundene Spu lenwicklung der elektrischen Maschine 3 auf ein positives elektrisches Potential des Gleichspannungszwischenkreises des Stromrichters 1 gelegt wird. Der Wert 0 einer Ziffer des Zif ferntripels steht für eine Schalterstellung der dieser Ziffer zugeordneten Halbbrücke 5, 6, 7, bei der der erste elektroni sche Schalter 9 der Halbbrücke 5, 6, 7 ausgeschaltet und der zweite elektronische Schalter 10 eingeschaltet ist, wodurch die mit der Halbbrücke 5, 6, 7 verbundene Spulenwicklung der elektrischen Maschine 3 auf ein negatives elektrisches Poten tial des Gleichspannungszwischenkreises des Stromrichters 1 gelegt wird. Die Grundspannungsraumzeiger, die einen Schalt zustand repräsentieren, der durch eines der Zifferntripel 100, 010, 001, 110, 101 oder 011 dargestellt wird, werden als aktive Grundspannungsraumzeiger bezeichnet. Die beiden Grund spannungsraumzeiger, die einen Schaltzustand repräsentieren, der durch eines der Zifferntripel 000 oder 111 dargestellt wird, werden als passive Grundspannungsraumzeiger oder Triple triplet is represented, the three digits each can assume the values 0 or 1 and are each assigned to a half bridge 5, 6, 7. The value 1 of a digit of the triple digits represents a switch position of the half-bridge 5, 6, 7 assigned to this number, in which a first electronic switch 9 of the half-bridge 5, 6, 7 is switched on and the second electronic switch 10 is switched off, as a result of which the the half-bridge 5, 6, 7 connected Spu lenwicking of the electrical machine 3 is placed on a positive electrical potential of the DC link of the converter 1. The value 0 of a digit of the Zif remote triple stands for a switch position of the half-bridge 5, 6, 7 assigned to this number, in which the first electronic switch 9 of the half-bridge 5, 6, 7 is switched off and the second electronic switch 10 is switched on, as a result of which the with the half bridge 5, 6, 7 connected coil winding of the electrical machine 3 to a negative electrical potential of the DC intermediate circuit of the converter 1 is placed. The basic voltage space pointers, which represent a switching state, which is represented by one of the number triples 100, 010, 001, 110, 101 or 011, are referred to as active basic voltage space pointers. The two basic voltage space pointers, which represent a switching state, which is represented by one of the digit triples 000 or 111, are called passive basic voltage space pointers or
Nullspannungsraumzeiger bezeichnet . Denoted zero voltage space pointer.
Erfindungsgemäß werden die Schaltzustände der Halbbrücken 5,According to the switching states of the half bridges 5,
6, 7 mit einer Raumzeigermodulation mit einer Pulsperiode ge steuert. Dabei wird wie üblich für jede Pulsperiode ein Soll raumzeiger 13 für einen über die Pulsperiode gemittelten Schaltzustandsmittelwert der Schaltzustände der Halbbrü cken 5, 6, 7 vorgegeben, wobei in der Pulsperiode zwischen6, 7 controls with a space vector modulation with a pulse period. In this case, as is customary for each pulse period, a set space pointer 13 is specified for an average switching state of the switching states of the half-bridges 5, 6, 7, averaged over the pulse period, with the pulse period between
Schaltzuständen gewechselt wird, die von den beiden dem Soll raumzeiger 13 benachbarten aktiven Grundspannungsraumzeigern 15, 16, 17 und den beiden Nullspannungsraumzeigern oder einerSwitching states is changed, the two of the target space pointer 13 adjacent active basic voltage space pointers 15, 16, 17 and the two zero voltage space pointers or one
Untermenge dieser Raumzeiger repräsentiert werden. Im Unterschied zu der herkömmlichen Raumzeigermodulation wird jedoch eine Mindestverweilzeit vorgegeben und jeder von einem aktiven Grundspannungsraumzeiger 15, 16, 17 repräsentierte Schaltzustand der Halbbrücken 5, 6, 7 wird wenigstens für die Mindestverweilzeit beibehalten. Ferner wird eine Schalter stellungsmindestzeit vorgegeben und eine Schalterstellung je der Halbbrücke 5, 6, 7 wird wenigstens für die Schalterstel lungsmindestzeit beibehalten. Des Weiteren werden die Schalt zustände der Halbbrücken 5, 6, 7 nur derart geändert, dass sich je zwei aufeinander folgende Schaltzustände der Halb brücken 5, 6, 7 nur durch die Schalterstellungen genau einerSubset of these space pointers are represented. In contrast to the conventional space vector modulation, however, a minimum dwell time is specified and each switching state of the half bridges 5, 6, 7 represented by an active basic voltage space vector 15, 16, 17 is maintained at least for the minimum dwell time. Furthermore, a switch position minimum time is specified and a switch position for each half-bridge 5, 6, 7 is maintained at least for the switch position minimum time. Furthermore, the switching states of the half bridges 5, 6, 7 are only changed such that two consecutive switching states of the half bridges 5, 6, 7 are changed only by the switch positions of exactly one
Halbbrücke 5, 6, 7 voneinander unterscheiden. Differentiate half bridge 5, 6, 7 from each other.
Mit diesen Vorgaben lässt sich nicht jeder von einem Soll raumzeiger 13 repräsentierte Schaltzustandsmittelwert reali sieren, da die Mindestverweilzeit für durch aktive Grundspan nungsraumzeiger 15, 16, 17 repräsentierte Schaltzustände der Halbbrücken 5, 6, 7 und die Schalterstellungsmindestzeit für die Schalterstellungen jeder Halbbrücke 5, 6, 7 eingehalten werden müssen. In Figur 2 sind in dem gezeigten Ausschnitt der Raumzeigerebene Bereiche dargestellt, deren Punkte reali sierbare Schaltzustandsmittelwerte repräsentieren. Dies sind Dreieckflächen 19, 20 zwischen den aktiven Grundspannungs raumzeigern 15 und 16 beziehungsweise 16 und 17, die von den Zifferntripeln 100, 110, 010 und 000 (beziehungsweise 111) repräsentierten Punkte, sowie Strecken 21 bis 25, die zwi schen diesen Punkten verlaufen. Die Punkte eines zwischen einer Dreieckfläche 19, 20 und den ihr benachbarten Strecken 21 bis 25 liegenden Bereichs repräsentieren dagegen nicht re alisierbare Schaltzustandsmittelwerte . With these specifications, not every switching state mean value represented by a desired room pointer 13 can be realized, since the minimum dwell time for switching states of the half bridges 5, 6, 7 represented by active basic voltage room pointers 15, 16, 17 and the minimum switch position time for the switch positions of each half bridge 5, 6 , 7 must be observed. In FIG. 2, the section of the space vector plane shown shows areas whose points represent realizable switching state mean values. These are triangular areas 19, 20 between the active basic voltage space pointers 15 and 16 or 16 and 17, the points represented by the triplets 100, 110, 010 and 000 (or 111), as well as distances 21 to 25, which run between these points. In contrast, the points of a region lying between a triangular surface 19, 20 and the adjacent paths 21 to 25 represent switching average values that cannot be implemented.
Ein durch einen Punkt in der Dreieckfläche 19 repräsentierter Schaltzustandsmittelwert wird beispielsweise durch eine zeit liche Schaltzustandsabfolge 000 100 110 111 110A switching state mean value represented by a point in the triangular area 19 becomes, for example, a temporal switching state sequence 000 100 110 111 110
-^100 -» 000 innerhalb einer Pulsperiode realisiert. Ein durch einen Punkt auf der Strecke 22 repräsentierter Schalt zustandsmittelwert wird beispielsweise durch einen Wechsel zwischen den Schaltzuständen 110 und 111 innerhalb einer Pulsperiode realisiert. Ein durch einen Punkt auf der Strecke 24 repräsentierter Schaltzustandsmittelwert wird beispiels weise durch eine zeitliche Schaltzustandsabfolge 100 110- ^ 100 - »000 realized within one pulse period. A switching state mean value represented by a point on the route 22 is determined, for example, by a change between the switching states 110 and 111 within a Pulse period realized. A switching state mean value represented by a point on the route 24 is, for example, by a temporal switching state sequence 100 110
100 innerhalb einer Pulsperiode realisiert. Entsprechendes gilt für die anderen realisierbaren Schaltzustandsmittelwer- te . Ein Sollraumzeiger 13 mit dem Raumzeigerbetrag Null wird realisiert, indem über die gesamte Pulsperiode derselbe 100 realized within a pulse period. The same applies to the other realizable switching state averages. A target space pointer 13 with the space pointer amount zero is realized by the same over the entire pulse period
Nullspannungsraumzeiger eingestellt wird. Zero voltage space pointer is set.
Als Mindestverweilzeit wird beispielsweise mindestens das Doppelte einer Zeitdauer zwischen einer Schaltzustandsände- rung eines Schaltzustands der Halbbrücken 5, 6, 7 und der durch die Schaltzustandsänderung erzeugten Phasenspannungsän derung der Phasenspannungen der elektrischen Maschine 3 vor gegeben. Diese Zeitdauer ist beispielsweise eine Signallauf zeit eines Signals in einem den Stromrichter 1 mit der elektrischen Maschine 3 verbindenden Verbindungskabel von den Halbbrücken 5, 6, 7 zu Anschlussklemmen der elektrischen Ma schine 3. The minimum dwell time is, for example, at least twice a time period between a change in the switching state of a switching state of the half-bridges 5, 6, 7 and the change in phase voltage generated by the change in the switching state of the phase voltages of the electrical machine 3. This time period is, for example, a signal running time of a signal in a connecting cable connecting the converter 1 to the electrical machine 3 from the half bridges 5, 6, 7 to connecting terminals of the electrical machine 3.
Alternativ wird als Mindestverweilzeit der Kehrwert einer von einer Längsinduktivität und einer Wicklungskapazität der elektrischen Maschine 3 abhängigen Resonanzfrequenz der elektrischen Maschine 3 vorgegeben. Alternatively, the reciprocal of a resonance frequency of the electrical machine 3 which is dependent on a longitudinal inductance and a winding capacitance of the electrical machine 3 is specified as the minimum dwell time.
In Figur 2 ist ein Sollraumzeiger 13 dargestellt, der einen nicht realisierbaren Schaltzustandsmittelwert repräsentiert, da zu dessen Realisierung der Schaltzustand 100 nur eine sehr kurze Zeit innerhalb einer Pulsperiode eingestellt werden müsste, wodurch entsprechend der oben genannten Schaltzu standsabfolge in der Dreieckfläche 19 ein fast instantaner Schaltzustandswechsel zwischen den Schaltzuständen 000 und 110 erfolgen würde und somit zwei Halbbrücken 5, 6, 7 fast gleichzeitig gleichartig umgeschaltet werden würden. In einem solchen Fall wird ein Schaltzustandsmittelwert eingestellt, der von einem wenig von dem Sollraumzeiger 13 abweichenden Ersatzraumzeiger 27 repräsentiert wird. In dem in Figur 2 ge zeigten Beispiel stimmt der Raumzeigerbetrag des Ersatzraum- zeigers 27 mit dem Raumzeigerbetrag des Sollraumzeigers 13 überein und der Raumzeigerwinkel des Ersatzraumzeigers 27 weicht möglichst wenig von dem Raumzeigerwinkel des Sollraum zeigers 13 ab. Alternativ wird zur Bildung des Ersatzraumzei gers 27 eine Zeitdauer verkürzt, in der der Schaltzustand der Halbbrücken 5, 6, 7 innerhalb der Pulsperiode von einem der aktiven Grundspannungsraumzeiger 15, 16, 17 repräsentiert wird. Dabei wird vorzugsweise die Zeitdauer desjenigen akti ven Grundspannungsraumzeigers 15, 16, 17 verkürzt, der am längsten innerhalb der Pulsperiode zur Realisierung des Soll raumzeigers 13 verwendet werden würde. In Figure 2, a target space pointer 13 is shown, which represents a non-realizable switching state mean value, since the switching state 100 would only have to be set for a very short time within a pulse period, so that an almost instantaneous switching state change in the triangular area 19 in accordance with the switching state sequence mentioned above would occur between the switching states 000 and 110 and thus two half-bridges 5, 6, 7 would be switched over almost identically. In such a case, an average switching state value is set, which is represented by a spare space pointer 27 which differs slightly from the target space pointer 13. In the example shown in FIG. 2, the space pointer amount of the replacement space is correct. pointer 27 coincides with the space pointer amount of the target space pointer 13 and the space pointer angle of the replacement space pointer 27 differs as little as possible from the space pointer angle of the target space pointer 13. Alternatively, a period of time is shortened in order to form the spare space vector 27, in which the switching state of the half bridges 5, 6, 7 is represented within the pulse period by one of the active basic voltage space pointers 15, 16, 17. The duration of the active basic voltage space vector 15, 16, 17 that would be used longest within the pulse period for realizing the desired space vector 13 is preferably shortened.
Die Figuren 3 und 4 zeigen zwei verschiedene Ausführungsvari anten der Erfindung, gemäß denen ein Sollraumzeiger 14 einer Pulsperiode der Raumzeigermodulation gebildet wird, wenn in der vorhergehenden Pulsperiode ein von dem Sollraumzeiger 13 der vorhergehenden Pulsperiode abweichender Ersatzraumzei ger 27 zur Bildung des Schaltzustandsmittelwertes der Schalt zustände der Halbbrücken 5, 6, 7 verwendet wurde. Bei beiden Ausführungsvarianten wird ein Differenzraumzeiger 29 zwischen dem Sollraumzeiger 13 und dem Ersatzraumzeiger 27 der vorher gehenden Pulsperiode gebildet und der Sollraumzeiger 14 wird gegenüber dem ursprünglich vorgegebenen Sollraumzeiger 14" in Abhängigkeit von dem Differenzraumzeiger 29 der vorhergehen den Pulsperiode modifiziert, um eine in der vorhergehenden Pulsperiode durch die Verwendung des Ersatzraumzeigers 27 an stelle des Sollraumzeigers 13 verursachte Abweichung der Spannungs-Zeit-Fläche von deren Sollwert auszugleichen. FIGS. 3 and 4 show two different embodiments of the invention, according to which a target space pointer 14 of a pulse period of the space vector modulation is formed if, in the previous pulse period, a replacement space pointer 27 deviating from the target space pointer 13 of the previous pulse period for forming the switching state mean value of the switching states Half bridges 5, 6, 7 was used. In both embodiments, a difference space pointer 29 is formed between the target space pointer 13 and the spare space pointer 27 of the previous pulse period and the target space pointer 14 is modified by one in the previous pulse period compared to the originally specified target space pointer 14 ″ depending on the difference space pointer 29 of the previous pulse period to compensate for the deviation of the voltage-time area from its target value caused by the use of the spare space pointer 27 instead of the target space pointer 13.
Bei der in Figur 3 gezeigten Bildung des Sollraumzeigers 14 wird der Differenzraumzeiger 29 der vorhergehenden Pulsperio de zu dem ursprünglich vorgegebenen Sollraumzeiger 14" ad diert . In the formation of the target space pointer 14 shown in FIG. 3, the difference space pointer 29 of the preceding pulse period is added to the originally predetermined target space pointer 14 ″.
Bei der in Figur 4 gezeigten Bildung des Sollraumzeigers 14 wird der Differenzraumzeiger 29 um einen Differenzwinkel zwischen dem Raumzeigerwinkel des ursprünglich für die Puls periode vorgegebenen Sollraumzeigers 14" und dem Raumzeiger- winkel des Sollraumzeigers 13 der vorhergehenden Pulsperiode gedreht und der gedrehte Differenzraumzeiger 31 wird zu dem ursprünglich für die Pulsperiode vorgegebenen Sollraumzei ger 14" addiert. In the formation of the target space pointer 14 shown in FIG. 4, the difference space pointer 29 is moved by a difference angle between the space pointer angle of the target space pointer 14 ″ originally specified for the pulse period and the space pointer Angle of the target space pointer 13 of the previous pulse period rotated and the rotated differential space pointer 31 is added to the target space pointer 14 "originally specified for the pulse period.
Das oben anhand der Figuren 2 bis 4 beschriebene Verfahren wird vorzugsweise, beispielsweise mittels eines Parameters für den Stromrichter 1, nur aktiviert, wenn die elektrische Maschine 3 mit Phasenspannungen, deren Amplituden in einem vorgegebenen Spannungsbereich liegen, betrieben wird. Dabei wird für die Aktivierung des Verfahrens ein Spannungsbereich vorgegeben, in dem die elektrische Maschine 3 einer Span nungsbelastung ausgesetzt ist, für die sie bei einem Steue rungsverfahren mit einer herkömmlichen Raumzeigermodulation nicht ausgelegt ist. Bei Phasenspannungen außerhalb dieses Spannungsbereiches wird die elektrische Maschine 3 dagegen mit einer herkömmlichen Raumzeigermodulation gesteuert. The method described above with reference to FIGS. 2 to 4 is preferably only activated, for example by means of a parameter for the converter 1, if the electrical machine 3 is operated with phase voltages whose amplitudes are within a predetermined voltage range. A voltage range is specified for the activation of the method, in which the electrical machine 3 is exposed to a voltage load for which it is not designed in a control method with a conventional space vector modulation. In the case of phase voltages outside this voltage range, on the other hand, the electrical machine 3 is controlled with a conventional space vector modulation.
Dadurch wird berücksichtigt, dass bei der erfindungsgemäß mo difizierten Raumzeigermodulation ein Rippelstrom in der elektrischen Maschine 3 gegenüber einer herkömmlichen Raum zeigermodulation leicht ansteigt, so dass die erfindungsgemäß modifizierte Raumzeigermodulation gegenüber der herkömmlichen Raumzeigermodulation nur bei Spannungsbelastungen der This takes into account the fact that in the space vector modulation modified according to the invention, a ripple current in the electrical machine 3 increases slightly compared to a conventional space vector modulation, so that the space vector modulation modified according to the invention compared to the conventional space vector modulation only when the voltage loads on the
elektrischen Maschine 3 vorteilhaft ist, für die sie bei einem Steuerungsverfahren mit einer herkömmlichen Raumzeiger modulation nicht ausgelegt ist. Electrical machine 3 is advantageous, for which it is not designed in a control method with a conventional space vector modulation.
Obwohl die Erfindung im Detail durch bevorzugte Ausführungs beispiele näher illustriert und beschrieben wurde, so ist die Erfindung nicht durch die offenbarten Beispiele eingeschränkt und andere Variationen können vom Fachmann hieraus abgeleitet werden, ohne den Schutzumfang der Erfindung zu verlassen. Although the invention has been illustrated and described in detail by means of preferred exemplary embodiments, the invention is not restricted by the disclosed examples and other variations can be derived therefrom by a person skilled in the art without departing from the scope of the invention.
Claims
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EP18203379.5A EP3648333A1 (en) | 2018-10-30 | 2018-10-30 | Spacevectormodulation for control of a polyphase electric machine with minimum switch state dwelling times |
PCT/EP2019/078724 WO2020088991A1 (en) | 2018-10-30 | 2019-10-22 | Space vector modulation method taking into account minimum switching status times for controlling a multi-phase electric machine |
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EP3834279A1 true EP3834279A1 (en) | 2021-06-16 |
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EP18203379.5A Withdrawn EP3648333A1 (en) | 2018-10-30 | 2018-10-30 | Spacevectormodulation for control of a polyphase electric machine with minimum switch state dwelling times |
EP19801679.2A Pending EP3834279A1 (en) | 2018-10-30 | 2019-10-22 | Space vector modulation method taking into account minimum switching status times for controlling a multi-phase electric machine |
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EP18203379.5A Withdrawn EP3648333A1 (en) | 2018-10-30 | 2018-10-30 | Spacevectormodulation for control of a polyphase electric machine with minimum switch state dwelling times |
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US (1) | US11356048B2 (en) |
EP (2) | EP3648333A1 (en) |
CN (1) | CN113056869B (en) |
WO (1) | WO2020088991A1 (en) |
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EP3945675A1 (en) * | 2020-07-30 | 2022-02-02 | Siemens Aktiengesellschaft | Power converter and method for operating a power converter |
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FR2746982B1 (en) * | 1996-03-28 | 1998-05-07 | Schneider Electric Sa | FREQUENCY CONVERTER FOR RECIPROCATING MOTOR |
US20060071627A1 (en) * | 2002-03-28 | 2006-04-06 | Ho Eddy Y Y | Motor current reconstruction via DC bus current measurement |
KR100638866B1 (en) * | 2002-03-28 | 2006-10-26 | 인터내쇼널 렉티파이어 코포레이션 | Reproducing Motor Current by Measuring DC Bus Current |
DE102008018885A1 (en) * | 2008-04-14 | 2009-10-22 | Sew-Eurodrive Gmbh & Co. Kg | Printed circuit board, method for determining a current space indicator, inverter, circuit board and series of converters |
DE102008025408B4 (en) * | 2008-05-27 | 2024-06-20 | Sew-Eurodrive Gmbh & Co Kg | Control or regulation method for a converter |
CN101769953B (en) * | 2010-01-14 | 2012-10-17 | 东元总合科技(杭州)有限公司 | Phase current detection method of motor based on direct-current bus current |
CN102307018B (en) * | 2011-08-30 | 2013-12-25 | 华北电力大学 | Inverter circuit and voltage space vector pulse width modulation method thereof |
DE102012020652A1 (en) * | 2012-10-19 | 2014-04-24 | Robert Bosch Gmbh | Method for controlling power converter for e.g. brushless direct current motor, involves accounting attitude borders for controllable shift elements in form of maximum voltages for default voltages |
US9048726B1 (en) * | 2013-03-11 | 2015-06-02 | The Boeing Company | Power system having repetitive control in symmetric sequences with harmonics cancellation |
DE102014108667A1 (en) * | 2014-06-20 | 2015-12-24 | Technische Universität Braunschweig | Power converter and computer program |
US9236828B1 (en) * | 2014-07-03 | 2016-01-12 | Rockwell Automation Technologies, Inc. | Methods and power conversion system control apparatus to control IGBT junction temperature at low speed |
CN104702138B (en) * | 2015-02-13 | 2017-09-22 | 广东美的制冷设备有限公司 | Pass through PWM waveform modification method during single resistance detection DC bus current |
JP6583000B2 (en) * | 2016-01-07 | 2019-10-02 | 株式会社デンソー | Control device for rotating electrical machine |
US9608545B1 (en) * | 2016-03-02 | 2017-03-28 | Faraday & Future Inc. | Switching interference suppression in motor driving circuits using space vector pulse width modulation (PWM) |
CN107300633B (en) * | 2017-08-23 | 2019-12-20 | 上海船舶研究设计院(中国船舶工业集团公司第六0四研究院) | Current source type frequency converter power grid voltage observation method, device and system |
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2018
- 2018-10-30 EP EP18203379.5A patent/EP3648333A1/en not_active Withdrawn
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2019
- 2019-10-22 CN CN201980072245.6A patent/CN113056869B/en active Active
- 2019-10-22 EP EP19801679.2A patent/EP3834279A1/en active Pending
- 2019-10-22 WO PCT/EP2019/078724 patent/WO2020088991A1/en unknown
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US11356048B2 (en) | 2022-06-07 |
EP3648333A1 (en) | 2020-05-06 |
CN113056869B (en) | 2024-07-05 |
WO2020088991A1 (en) | 2020-05-07 |
US20210384860A1 (en) | 2021-12-09 |
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