Title of Invention	METHOD FOR OPERATING A CONVERTER CIRCUIT WITH VOLTAGE BOOSTING
Abstract	Method for operating a converter circuit with voltage boosting (2, 500) with N half-bridges (8,5l0a-c), which in each case can be connected by their centre connection (9, 512a-c) to a phase (PI-5) of an N-phase generator (4, 502) and at an end side are connected in parallel with a series circuit formed by two capacitances (19, 524a, b), wherein each half-bridge (8, 510a-c) contains a Top switch (12a, 516a-c) and a Bot switch (12b, 518a-c), in which, in a PWM method with a fixed period duration (T): -at the beginning of the period duration (T), all the TOP switches (12a, 516a-c) are simultaneously switched on for the duration of a TOP switched-on interval (Ton, -after half the period duration (T/2) all the BOT switches (12b, 518a-c) are simultaneously switched on for the duration of a BOT switched-on interval (Ton, b), -wherein TOP switched-on interval (Ton, a), and BOT switched-on interval (Ton, b) amount at most to half the period duration (T/2).

Title of Invention

METHOD FOR OPERATING A CONVERTER CIRCUIT WITH VOLTAGE BOOSTING

Abstract

Method for operating a converter circuit with voltage boosting (2, 500) with N half-bridges (8,5l0a-c), which in each case can be connected by their centre connection (9, 512a-c) to a phase (PI-5) of an N-phase generator (4, 502) and at an end side are connected in parallel with a series circuit formed by two capacitances (19, 524a, b), wherein each half-bridge (8, 510a-c) contains a Top switch (12a, 516a-c) and a Bot switch (12b, 518a-c), in which, in a PWM method with a fixed period duration (T): -at the beginning of the period duration (T), all the TOP switches (12a, 516a-c) are simultaneously switched on for the duration of a TOP switched-on interval (Ton, -after half the period duration (T/2) all the BOT switches (12b, 518a-c) are simultaneously switched on for the duration of a BOT switched-on interval (Ton, b), -wherein TOP switched-on interval (Ton, a), and BOT switched-on interval (Ton, b) amount at most to half the period duration (T/2).

Full Text	FORM 2 THE PATENT ACT 197 0 (39 of 1970) The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10, and rule 13) TITLE OF INVENTION METHOD FOR OPERATING A CONVERTER CIRCUIT WITH VOLTAGE BOOTING APPLICANT(S) a) Name b) Nationality c) Address SEMIKRON ELEKTRONIK GMBH & CO. GERMAN Company SIGMUNDSTRASSE 2 00, 90431 NUERNBERG, GERMANY KG PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed : - The invention relates to a method for operating a converter circuit with voltage boosting. Electrical three-phase generators serve for generating electrical energy that is generally fed into a supply voltage system. In the case of specific generators, e.g. in wind power installations dependent on the instantaneous wind conditions, their output speed, power or voltage can fluctuate or be neither predictable nor controllable. Since the voltage supplied by the generator can thus lie below the voltage of the system to be fed, a boost converter (boost) circuit is connected between generator and system. Particularly for generators having a centre connection, so-called converter circuits are used which, relative to a centre potential, generate a positive and negative voltage in a DC voltage intermediate circuit having two capacitors or capacitances connected in series, wherein the voltages of the respective capacitors can be set or regulated independently of one another. Unbalances in the supply voltage system or generator can thus be compensated for. For this purpose, each capacitor has an assigned boost converter circuit. A circuit arrangement 500 on which the invention is based is known e.g. from EP 1 313 206 Bl and shown in Fig. 4 (without dashed connecting lines 11a, b). The three phases PI to P3 of a generator 502 are connected to an inverter 506 via an inductor block 504 or respectively via an inductor LI to L3. In this case, the three phases PI to P3 having a peak voltage Us are passed to a respective centre connection 512a-c of three half-bridges 510a-c of the inverter 506. From each centre connection, a Top switch 516a-c leads to a common Top connection 514 and a Bot switch 516a-c leads to a common Bot connection 515. In this case, each switch comprises an IGBT 520 with diode 522 reverse-connected in parallel. An intermediate circuit 508 is connected between Top connection 514 and Bot connection 515, said intermediate circuit containing two series-connected capacitors 524a, b, the centre connection 526 of which is connected to the centre connection M of the generator 502. By way of example, it is known from US 6,567,283 B2 to insert between a diode rectifier and the intermediate circuit 508 two series-connected Top and Bot IGBTs with freewheeling diodes, which are connected in parallel with the capacitors 524a, b via converter diodes lying in the Top and Bot connections 514, 515. The short-circuiting of the generator for boost purposes is thus transferred from the inverter into a separate boost branch. In accordance with Fig. 5, a further circuit arrangement is known from US 6,879,053. The phases P1 to P3 are in this case conducted to a diode rectifier 550 via the inductor block 504. The rectified voltage is then passed to a DC-DC converter 552, which charges the capacitances 524a, b. The DC-DC converter 552 contains two step-up converters 554a, b, one each per series-connected capacitor 524a, b. The driving of the known booster converters is relatively simple to implement since they act on the already rectified voltage and no longer have to be synchronized with the generator phases. However, with three switchhalf-bridges on three diode half-bridges and four switch half-bridges, the number of semiconductor modules required is considerable. This is because in practice fully equipped IGBT half-bridges with freewheeling diodes are in each case used for the series connection of a switch and the associated converter diode, wherein the IGBT connected in parallel with the converter diode remains unused. It is an object of the present invention to specify a drive method for a converter circuit with voltage boosting and the smallest possible number of components. The object is achieved by means of a method in accordance with Patent Claim 1, which involves operating a converter circuit with voltage boosting which has N half-bridges. The half-bridges in each case can be connected by their centre connection to a phase of an N-phase generator. At an end side the half-bridges are connected in parallel with a series circuit formed by two capacitances. Depending on the application, a centre connection of the generator can additionally be connected to the centre connection between the two capacitances. Each half-bridge contains a Top switch and a Bot switch. A PWM method with a fixed period duration is carried out in accordance with the method according to the invention. At the beginning of the period duration, all the Top switches are simultaneously switched on for the duration of a Top switched-on interval. After half the period duration all the Bot switches are simultaneously switched on for the duration of a Bot switched-on interval. In this case, Top switched-on interval and Bot switched-on interval are each less than or equal to half the period duration. In this case, the PWM method according to the invention is not oriented towards the phase angle of the output voltages of the generator. The clock period of the PWM method is coupled to the output frequency of the generator only insofar as the PWM frequency should be significantly higher than the maximum output frequency, e.g. in the range of plural 10-fold, e.g. 60-fold. Since in each case all the Top switches and all the Bot switches are simultaneously switched on and off, no particular synchronization or other precautions have to be implemented here either. The known circuit in accordance with Fig. 5 can therefore also be extended according to the invention by common control lines 11a, b (depicted in dashed fashion) that respectively connect the inputs of all the Top and Bot switches. The topology of the converter circuit remains simple and cost-effective since only N standard power semiconductor modules are required as semiconductor components. The corresponding half-bridges are generally only equipped with the required components, such that the latter are fully utilized. The function of the coils in the inductor block in Fig. 5 is performed in this case by the windings of the generator. Top and Bot switched-on intervals generally have an identical duration. The voltage charged onto the respective Top and Bot capacitors is then likewise identical in magnitude; the voltage of the centre connection of the capacitors lies symmetrically between the end voltages. In one preferred embodiment of the invention, the switched-on interval of Top and Bot switches is chosen to have different lengths. This can also be realized in a particularly simple manner since no other synchronizations whatsoever between the Top or Bot switches of the individual phases are required here. What is achieved as a result of this is that the two capacitors are charged to different voltage values, in other words it is thus possible to shift the centre voltage on the capacitors in the DC voltage intermediate circuit. In a further preferred embodiment of the method, the generator has a constant or, in the case of fluctuations, maximum operating frequency fB. The period duration is then chosen as a fraction in the range of 1/10 or less, e.g. approximately 1/60 of the period duration of the operating frequency, that is say as l/60fB. In other words, the switches are operated with a frequency more then 10 times, e.g. 60 times, the maximum operating frequency of the generator. It is thereby possible to achieve a particularly low residual ripple of the generated DC voltage on the capacitors since, through the superposition of the Top and Bot switched-on intervals with half the period duration, the resulting frequency doubles again. The known conductor circuits can also be cascaded by K such circuits being connected in parallel at the connections of the intermediate circuits, that is to say the end connections of the capacitor series circuits. In one preferred embodiment, the respective Top and Bot switches of the respective converter circuits are then switched on. with a time offset of 1/2 K times the period duration. In other words, e.g. in the case of a parallel connection of four converter circuits, in the first half of the period duration of the PWM method, at temporally identical spacings of one eighth of the period duration, all four Top switches of the four circuits are successively switched on for the duration of the switched-on intervals. In the second half of the period duration, all four Bot switches of the four boost circuits are then successively switched on likewise with a time offset of one eighth of the period duration. The frequency of the residual ripple of the generated DC voltage thus rises again by the factor K. In a further advantageous embodiment, each of the capacitances is charged to a voltage value of more than half the peak voltage of the generator. It is thereby possible to operate the circuit for voltage boosting with respect to the generator. The driving of a converter circuit is greatly simplified by the method according to the invention. In the case of a more than three-phase, e.g. five-phase, generator system, the known fundamental advantages of polyphase systems arise, such as e.g. a lower residual ripple of the output voltages. On account of the complexity of previous drive methods for converter circuits, however, polyphase systems were previously able to be utilized only with considerable outlay. By means of the method according to the invention, the use of converters for polyphase systems is practicable and can be utilized in a simple manner. The number of phases in the system can therefore be chosen as desired without the control outlay for the converter circuit increasing. For a further description of the invention, reference is made to the exemplary embodiments in the drawings, in which, in each case in a basic schematic diagram: Fig. 1 shows the temporal profile of the PWM drive signals in the case of symmetrical driving of the known converter circuit from Fig. 5, Fig. 2 shows the temporal profile of the PWM drive signals and of the generated voltages in the case of asymmetrical driving, Fig. 3 shows a five-phase converter circuit operated by the method according to the invention, Fig. 4 shows a three-phase converter circuit in accordance with the prior art, Fig. 5 shows an alternative three-phase converter circuit in accordance with the prior art. Fig. 1 shows the PWM signals 22a, b, which are fed to the control inputs 10a, b of the Top and Bot switches 516a-c and 518a-c from Fig. 4, against time t in ms. The PWM generator 16 (not shown in Fig. 4) that generates the signals is in this case operated with a constant clock frequency fT, which is significantly above the operating frequency fB, namely fT = X*fB, or period duration T. By means of the parallel connection according to the invention of the Top switches 516a-c and of the Bot switches 518a-c on the basis of the control lines 11a, b, these are driven simultaneously in each case. According to the invention, the switch-on instants of the PWM signals 22a and 22b are offset by half the period duration T/2. The switched-on times The,a and T0n,b for the respective Top and Bot switches are chosen to be identical in magnitude. If it is assumed that the period duration T corresponds to an angle range of 360°, the switched-on time Ton,a of the Top switches lies in the range of 0° to 40° and the switched-on time Ton,b of the Bot switches lies in the range of 180° to 220°. The voltages U1 and U2 across the two capacitors of the intermediate circuit 20 or 508 are therefore opposite and equal in magnitude. As a result of the phase offset of the switched-on times in accordance with Fig. 1, the frequency of the ripple of the output voltage Ua is greater than that of the individual voltages Ul and U2 with respect to the centre potential at the centre connection 526. Fig. 2 shows the PWM signals 22a, b in the case of alternative driving of the converter circuit 500, in the case of which - for the above 360° consideration - the switched-on interval Ton,a of the Top switches with 0 to 60° is greater than the switched-on interval TDn,b of the Bot switches of 180° to 220°. On account of the longer PWM pulses at the top switches, the latter are in the conducting state for longer, the boost caused by them is increased, and the voltage U1 is therefore greater in magnitude than the voltage U2 The centre voltage at the centre connection 526 is therefore not symmetrical or at half of the output voltage UA. Fig. 3 shows a converter circuit 2 which corresponds to the known converter circuit from Fig. 4 in accordance with the prior art, but has been adapted for a generator 4 having five phases P1 to P5 The inverter 6 therefore contains five half-bridges 8 with their centre connections 9. The respective control inputs 10a of the Top switches 12a and the respective control inputs 10b of the Bot switches 12b are again connected in parallel via the respective control line 11a, b and passed to a respective common control output 14a, b of the PWM circuit 16. Moreover, the generator 4 does not have a centre connection, which would be connected to the centre connection of the intermediate circuit 20; the capacitors 19 are therefore only connected via a centre connection 18 that is not connected to the generator. The driving of the five-phase boost circuit 2 is effected identically to the above driving of the three-phase circuit with the same effects. A scaling of the number of phases is therefore easily possible with the method according to the invention. Polyphase systems with any desired number of phases above three can therefore easily be utilized. CLAIM: 1. Method for operating a converter circuit with voltage boosting (2, 500) with N half-bridges (8, 510a-c), which in each case can be connected by their centre connection (9, 512a-c) to a phase (PI-5) of an N-phase generator (4,502) and at an end side are connected in parallel with a series circuit formed by two capacitances (19, 524a, b), wherein each half-bridge (8, 510a-c) contains a Top switch (12a, 516a-c) and a Bot switch (12b, 518a-c), in which, in a PWM method with a fixed period duration (T): - at the beginning of the period duration (T), all the TOP switches (12a, 516a-c) are simultaneously switched on for the duration of a TOP switched-on interval (Ton, a), after half the period duration (T/2) all the BOT switches (12b, 518a-c) are simultaneously switched on for the duration of a BOT switched-on interval (Ton, b), wherein TOP switched-on interval (Ton, a), and BOT switched-on interval (Ton, b) amount at most to half the period duration (T/2). 2. Method according to Claim 1, in which TOP switched-on interval (Ton, a) and BOT switched-on interval (Ton, b) are chosen to have different lengths. 3. Method according to Claim 1 or 2, wherein the generator (4, 502) has an operating frequency (fB), in which approximately a value equal to plurally tenfold multiplication of the reciprocal value of the operating frequency (fB) is chosen as the period duration (T). 4. Method according to any of the preceding claims, wherein K converter circuits (2, 500) are connected in parallel at their capacitances (19, 524a, b), in which the Top switches (12a, 516a-c) and the Bot switches (12b, 518a-c) of the respective converter circuit (2, 500) are switched on with a time offset of 1/2 K times the period duration (T). Method according to any of the preceding claims, in which each of the capacitances (19, 524a, b) is charged to a voltage value of more than half the peak voltage (Us) of the generator (4,502).

Full Text

FORM 2
THE PATENT ACT 197 0 (39 of 1970)
The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10, and rule 13)

TITLE OF INVENTION

METHOD FOR OPERATING A CONVERTER CIRCUIT WITH VOLTAGE BOOTING

APPLICANT(S)
a) Name
b) Nationality
c) Address

SEMIKRON ELEKTRONIK GMBH & CO. GERMAN Company SIGMUNDSTRASSE 2 00, 90431 NUERNBERG, GERMANY

KG

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

The invention relates to a method for operating a converter circuit with voltage boosting.
Electrical three-phase generators serve for generating electrical energy that is generally fed into a supply voltage system. In the case of specific generators, e.g. in wind power installations dependent on the instantaneous wind conditions, their output speed, power or voltage can fluctuate or be neither predictable nor controllable. Since the voltage supplied by the generator can thus lie below the voltage of the system to be fed, a boost converter (boost) circuit is connected between generator and system. Particularly for generators having a centre connection, so-called converter circuits are used which, relative to a centre potential, generate a positive and negative voltage in a DC voltage intermediate circuit having two capacitors or capacitances connected in series, wherein the voltages of the respective capacitors can be set or regulated independently of one another. Unbalances in the supply voltage system or generator can thus be compensated for. For this purpose, each capacitor has an assigned boost converter circuit.
A circuit arrangement 500 on which the invention is based is known e.g. from EP 1 313 206 Bl and shown in Fig. 4 (without dashed connecting lines 11a, b). The three phases PI to P3 of a generator 502 are connected to an inverter 506 via an inductor block 504 or respectively via an inductor LI to L3. In this case, the three phases PI to P3 having a peak voltage Us are passed to a respective centre connection 512a-c of three half-bridges 510a-c of the inverter 506. From each centre connection, a Top switch 516a-c leads to a common Top connection 514 and a Bot switch 516a-c leads to a common Bot connection 515. In this case, each switch comprises an IGBT 520 with diode 522 reverse-connected in parallel.
An intermediate circuit 508 is connected between Top connection 514 and Bot connection 515, said intermediate circuit containing two series-connected capacitors 524a, b, the centre connection 526 of which is connected to the centre connection M of the generator 502.

By way of example, it is known from US 6,567,283 B2 to insert between a diode rectifier and the intermediate circuit 508 two series-connected Top and Bot IGBTs with freewheeling diodes, which are connected in parallel with the capacitors 524a, b via converter diodes lying in the Top and Bot connections 514, 515. The short-circuiting of the generator for boost purposes is thus transferred from the inverter into a separate boost branch.
In accordance with Fig. 5, a further circuit arrangement is known from US 6,879,053. The phases P1 to P3 are in this case conducted to a diode rectifier 550 via the inductor block 504. The rectified voltage is then passed to a DC-DC converter 552, which charges the capacitances 524a, b. The DC-DC converter 552 contains two step-up converters 554a, b, one each per series-connected capacitor 524a, b.
The driving of the known booster converters is relatively simple to implement since they act on the already rectified voltage and no longer have to be synchronized with the generator phases. However, with three switchhalf-bridges on three diode half-bridges and four switch half-bridges, the number of semiconductor modules required is considerable.
This is because in practice fully equipped IGBT half-bridges with freewheeling diodes are in each case used for the series connection of a switch and the associated converter diode, wherein the IGBT connected in parallel with the converter diode remains unused.
It is an object of the present invention to specify a drive method for a converter circuit with voltage boosting and the smallest possible number of components.
The object is achieved by means of a method in accordance with Patent Claim 1, which involves operating a converter circuit with voltage boosting which has N half-bridges. The half-bridges in each case can be connected by their centre connection to a phase of an N-phase generator. At an end side the half-bridges are connected in

parallel with a series circuit formed by two capacitances. Depending on the application, a centre connection of the generator can additionally be connected to the centre connection between the two capacitances. Each half-bridge contains a Top switch and a Bot switch.
A PWM method with a fixed period duration is carried out in accordance with the method according to the invention. At the beginning of the period duration, all the Top switches are simultaneously switched on for the duration of a Top switched-on interval. After half the period duration all the Bot switches are simultaneously switched on for the duration of a Bot switched-on interval. In this case, Top switched-on interval and Bot switched-on interval are each less than or equal to half the period duration.
In this case, the PWM method according to the invention is not oriented towards the phase angle of the output voltages of the generator. The clock period of the PWM method is coupled to the output frequency of the generator only insofar as the PWM frequency should be significantly higher than the maximum output frequency, e.g. in the range of plural 10-fold, e.g. 60-fold.
Since in each case all the Top switches and all the Bot switches are simultaneously switched on and off, no particular synchronization or other precautions have to be implemented here either. The known circuit in accordance with Fig. 5 can therefore also be extended according to the invention by common control lines 11a, b (depicted in dashed fashion) that respectively connect the inputs of all the Top and Bot switches.
The topology of the converter circuit remains simple and cost-effective since only N standard power semiconductor modules are required as semiconductor components. The corresponding half-bridges are generally only equipped with the required components, such that the latter are fully utilized. The function of the coils in the inductor block in Fig. 5 is performed in this case by the windings of the generator.

Top and Bot switched-on intervals generally have an identical duration. The voltage charged onto the respective Top and Bot capacitors is then likewise identical in magnitude; the voltage of the centre connection of the capacitors lies symmetrically between the end voltages.
In one preferred embodiment of the invention, the switched-on interval of Top and Bot switches is chosen to have different lengths. This can also be realized in a particularly simple manner since no other synchronizations whatsoever between the Top or Bot switches of the individual phases are required here. What is achieved as a result of this is that the two capacitors are charged to different voltage values, in other words it is thus possible to shift the centre voltage on the capacitors in the DC voltage intermediate circuit.
In a further preferred embodiment of the method, the generator has a constant or, in the case of fluctuations, maximum operating frequency fB. The period duration is then chosen as a fraction in the range of 1/10 or less, e.g. approximately 1/60 of the period duration of the operating frequency, that is say as l/60fB. In other words, the switches are operated with a frequency more then 10 times, e.g. 60 times, the maximum operating frequency of the generator. It is thereby possible to achieve a particularly low residual ripple of the generated DC voltage on the capacitors since, through the superposition of the Top and Bot switched-on intervals with half the period duration, the resulting frequency doubles again.
The known conductor circuits can also be cascaded by K such circuits being connected in parallel at the connections of the intermediate circuits, that is to say the end connections of the capacitor series circuits. In one preferred embodiment, the respective Top and Bot switches of the respective converter circuits are then switched on. with a time offset of 1/2 K times the period duration.
In other words, e.g. in the case of a parallel connection of four converter circuits, in the first half of the period duration of the PWM method, at temporally identical

spacings of one eighth of the period duration, all four Top switches of the four circuits are successively switched on for the duration of the switched-on intervals. In the second half of the period duration, all four Bot switches of the four boost circuits are then successively switched on likewise with a time offset of one eighth of the period duration. The frequency of the residual ripple of the generated DC voltage thus rises again by the factor K.
In a further advantageous embodiment, each of the capacitances is charged to a voltage value of more than half the peak voltage of the generator. It is thereby possible to operate the circuit for voltage boosting with respect to the generator.
The driving of a converter circuit is greatly simplified by the method according to the invention. In the case of a more than three-phase, e.g. five-phase, generator system, the known fundamental advantages of polyphase systems arise, such as e.g. a lower residual ripple of the output voltages. On account of the complexity of previous drive methods for converter circuits, however, polyphase systems were previously able to be utilized only with considerable outlay. By means of the method according to the invention, the use of converters for polyphase systems is practicable and can be utilized in a simple manner. The number of phases in the system can therefore be chosen as desired without the control outlay for the converter circuit increasing.
For a further description of the invention, reference is made to the exemplary embodiments in the drawings, in which, in each case in a basic schematic diagram:
Fig. 1 shows the temporal profile of the PWM drive signals in the case of symmetrical driving of the known converter circuit from Fig. 5,
Fig. 2 shows the temporal profile of the PWM drive signals and of the generated voltages in the case of asymmetrical driving,

Fig. 3 shows a five-phase converter circuit operated by the method according to the invention,
Fig. 4 shows a three-phase converter circuit in accordance with the prior art,
Fig. 5 shows an alternative three-phase converter circuit in accordance with the prior art.
Fig. 1 shows the PWM signals 22a, b, which are fed to the control inputs 10a, b of the Top and Bot switches 516a-c and 518a-c from Fig. 4, against time t in ms. The PWM generator 16 (not shown in Fig. 4) that generates the signals is in this case operated with a constant clock frequency fT, which is significantly above the operating frequency fB, namely fT = X*fB, or period duration T. By means of the parallel connection according to the invention of the Top switches 516a-c and of the Bot switches 518a-c on the basis of the control lines 11a, b, these are driven simultaneously in each case. According to the invention, the switch-on instants of the PWM signals 22a and 22b are offset by half the period duration T/2. The switched-on times The,a and T0n,b for the respective Top and Bot switches are chosen to be identical in magnitude. If it is assumed that the period duration T corresponds to an angle range of 360°, the switched-on time Ton,a of the Top switches lies in the range of 0° to 40° and the switched-on time Ton,b of the Bot switches lies in the range of 180° to 220°. The voltages U1 and U2 across the two capacitors of the intermediate circuit 20 or 508 are therefore opposite and equal in magnitude.
As a result of the phase offset of the switched-on times in accordance with Fig. 1, the frequency of the ripple of the output voltage Ua is greater than that of the individual voltages Ul and U2 with respect to the centre potential at the centre connection 526.
Fig. 2 shows the PWM signals 22a, b in the case of alternative driving of the converter circuit 500, in the case of which - for the above 360° consideration - the switched-on interval Ton,a of the Top switches with 0 to 60° is greater than the

switched-on interval TDn,b of the Bot switches of 180° to 220°. On account of the longer PWM pulses at the top switches, the latter are in the conducting state for longer, the boost caused by them is increased, and the voltage U1 is therefore greater in magnitude than the voltage U2 The centre voltage at the centre connection 526 is therefore not symmetrical or at half of the output voltage UA.
Fig. 3 shows a converter circuit 2 which corresponds to the known converter circuit from Fig. 4 in accordance with the prior art, but has been adapted for a generator 4 having five phases P1 to P5 The inverter 6 therefore contains five half-bridges 8 with their centre connections 9.
The respective control inputs 10a of the Top switches 12a and the respective control inputs 10b of the Bot switches 12b are again connected in parallel via the respective control line 11a, b and passed to a respective common control output 14a, b of the PWM circuit 16.
Moreover, the generator 4 does not have a centre connection, which would be connected to the centre connection of the intermediate circuit 20; the capacitors 19 are therefore only connected via a centre connection 18 that is not connected to the generator.
The driving of the five-phase boost circuit 2 is effected identically to the above driving of the three-phase circuit with the same effects. A scaling of the number of phases is therefore easily possible with the method according to the invention. Polyphase systems with any desired number of phases above three can therefore easily be utilized.

CLAIM:
1. Method for operating a converter circuit with voltage boosting (2, 500) with N
half-bridges (8, 510a-c), which in each case can be connected by their centre
connection (9, 512a-c) to a phase (PI-5) of an N-phase generator (4,502) and at
an end side are connected in parallel with a series circuit formed by two
capacitances (19, 524a, b), wherein each half-bridge (8, 510a-c) contains a Top
switch (12a, 516a-c) and a Bot switch (12b, 518a-c), in which, in a PWM
method with a fixed period duration (T):
- at the beginning of the period duration (T), all the TOP switches (12a, 516a-c) are simultaneously switched on for the duration of a TOP switched-on interval (Ton, a),
after half the period duration (T/2) all the BOT switches (12b, 518a-c) are simultaneously switched on for the duration of a BOT switched-on interval (Ton, b),
wherein TOP switched-on interval (Ton, a), and BOT switched-on interval (Ton, b) amount at most to half the period duration (T/2).
2. Method according to Claim 1, in which TOP switched-on interval (Ton, a) and BOT switched-on interval (Ton, b) are chosen to have different lengths.
3. Method according to Claim 1 or 2, wherein the generator (4, 502) has an operating frequency (fB), in which approximately a value equal to plurally tenfold multiplication of the reciprocal value of the operating frequency (fB) is chosen as the period duration (T).
4. Method according to any of the preceding claims, wherein K converter circuits (2, 500) are connected in parallel at their capacitances (19, 524a, b), in which the Top switches (12a, 516a-c) and the Bot switches (12b, 518a-c) of the respective converter circuit (2, 500) are switched on with a time offset of 1/2 K times the period duration (T).

Method according to any of the preceding claims, in which each of the capacitances (19, 524a, b) is charged to a voltage value of more than half the peak voltage (Us) of the generator (4,502).

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Patent Number

272867

Indian Patent Application Number

1971/MUM/2009

PG Journal Number

19/2016

Publication Date

06-May-2016

Grant Date

29-Apr-2016

Date of Filing

27-Aug-2009

Name of Patentee

SEMIKRON ELEKTRONIK GMBH & CO. KG

Applicant Address

SIGMUNDSTRASSE 200, 90431 NUERNBERG, GERMANY.

Inventors:

#	Inventor's Name	Inventor's Address
1	SCHREIBER DEJAN	PIRCKHEIMERSTR. 49, D-90408 NUERNBERG, GERMANY.

PCT International Classification Number

H03K17/687; H03K17/687

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	102008042693.8	2008-10-08	Germany