JPH10225181A - Ac power supplier and ac motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC power supplier, capable of suppressing an influence of high harmonic voltage to a load generated when an inverter is PWM driven, and an AC motor capable of reducing space high harmonics generated at drive control time by the inverter. SOLUTION: A device has a first/second inverter 2, 3 converting DC power into AC power supplied to a motor 5, first to third opening/closing switches 6 to 8 switching the first/second inverter 2, 3 to series connection between DC power positive/negative poles 21, 32 or to parallel connection relating to a battery, and a three-phase transformer 4 combining an output of the first/ second inverter 2, 3, connected in series or parallel by the first to third opening/ closing switches 6 to 8, supplied to the motor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC power supply device capable of switching and connecting a plurality of inverters (power converters) in series or in parallel, and an AC motor driven and controlled by the AC power supply device.

[0002]

2. Description of the Related Art As a conventional multiplex PWM inverter device, there is one disclosed in a literature (IEEJ, "Semiconductor Power Conversion Circuit", Ohmsha, 1987, p125, FIG. 6.3.18). This is to reduce the harmonics of the inverter output by shifting the phases of the output waveforms of the two PWM inverters and then combining the waveforms with the reactor.

[0003]

In the conventional multiple PWM inverter device, after the phases of the output waveforms of the respective PWM inverters are shifted, in a method of synthesizing the waveforms by the reactor, when the modulation rate is decreased to adjust the inverter output voltage. There is a problem that the harmonic component of the inverter output increases and the loss of the motor increases.

[0004] In addition, literature (same as above, p102 Table 6.2.1)
In the case shown in (a)), the two PWM inverters are shifted in phase and combined by a reactor to reduce harmonics, but as a result, a situation occurs in which the primary (fundamental wave) component also decreases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an AC power supply device capable of suppressing the influence of a harmonic voltage generated when an inverter is driven by PWM. With the goal.

Another object of the present invention is to provide an AC motor capable of reducing spatial harmonics generated by a winding of an AC motor driven and controlled by an AC power converter.

[0007]

According to a first aspect of the present invention, there is provided an AC power supply apparatus comprising: at least two power conversion means for converting DC power into AC power and supplying the AC power to a load; Series-parallel connection switching means for switching between series connection or parallel connection to the DC power supply between the DC power supply negative electrode, and combining the outputs of the plurality of power conversion means connected in series or parallel by the series-parallel connection switching means And power combining means for supplying the load.

According to another aspect of the present invention, the series-parallel connection switching means includes one DC input terminal connected to the DC power supply positive electrode and the other DC input terminal of the first AC power conversion means. A first opening / closing means having a DC input terminal connected to the other DC input terminal of the second AC power conversion means connected to the negative electrode of the DC power supply, the first opening / closing means being connected to the first AC power conversion means; A second opening / closing means connected between the other DC input terminal and the DC power supply negative electrode so as to be openable and closable, and a third opening / closing connection between the other DC input terminal of the second AC power conversion means and the DC power supply positive electrode. And opening and closing means.

According to a third aspect of the present invention, in the AC power supply device, the series-parallel connection switching means includes one DC input terminal connected to the DC power supply positive electrode and the other DC input terminal of the first AC power conversion means. A first opening / closing means having a DC input terminal connected to the other DC input terminal of the second AC power conversion means connected to the negative electrode of the DC power supply, the first opening / closing means being connected to the first AC power conversion means; A second switching means connected between the other DC input terminal and the DC power supply negative electrode so as to be openable and closable; and a connection means for connecting the other DC input terminal of the second power conversion means to the DC power supply positive electrode. Things.

According to a fourth aspect of the present invention, the connecting means is a diode having a cathode connected to the positive electrode of the DC power supply and an anode connected to the other DC input terminal of the second power converting means.

According to a fifth aspect of the present invention, in the AC motor,
A plurality of three-phase windings are electrically insulated and wound, and AC power generated by each AC power generator is input to each of the three-phase windings and combined.

According to a sixth aspect of the present invention, each of the three-phase windings is wound around the armature in the same phase while being electrically insulated.

According to a seventh aspect of the present invention, in the AC motor, each AC power generator is a first and a second PWM inverter, and the P and P output to each of the first and the second PWM inverters.
The carrier for generating the WM signal is obtained by shifting the phase of the carrier with respect to the second PWM inverter by π with respect to the phase of the carrier with respect to the first PWM inverter.

According to an eighth aspect of the present invention, in the AC motor, the first three-phase winding and the second three-phase winding are electrically insulated so that the armature has π.
It is wound with a / 6 phase shift.

According to a ninth aspect of the present invention, in the AC motor, three
The phase-turned first three-phase winding is Y-connected, and the second three-phase winding wound with the electrical angle π / 6 phase shifted from the first three-phase winding is △ -connected. And the first and second three-phase windings are connected in parallel.

An AC motor according to a tenth aspect is characterized in that:
AC power is supplied to the phase windings from the first AC power generator, and the electric power is supplied to the second three-phase windings by the first AC power generator and the electrical angle is shifted by π / 6 from the AC power. The AC power is supplied from a second AC power generator and driven.

According to the eleventh aspect, the ratio of the number of turns of the Y-connected first three-phase winding to the number of turns of the △ -connected second three-phase winding is approximately 1: 巻 線 3. is there.

According to a twelfth aspect of the present invention, in the AC motor, the first three-phase winding wound in three phases around the armature and Y-connected to the first three-phase winding is shifted in electrical angle π / 6 phase. The second three-phase winding wound and wound and connected in parallel is connected in parallel with the first three-phase winding.
The connected third three-phase winding and the third three-phase winding are formed by connecting in parallel a fourth three-phase winding wound and shifted by an electrical angle of π / 6 phase and △ -connected. is there.

According to a thirteenth aspect of the present invention, the AC motor supplies AC power from the first AC power generator to the first and second three-phase windings connected in parallel, and connects the third and the third connected in parallel. The AC power supplied from the first AC power generator and shifted from the AC power by an electrical angle π / 12 phase to the fourth three-phase winding is supplied from the second AC power generator to the fourth three-phase winding.

According to a fourteenth aspect of the present invention, when the first opening / closing means is in the open state, the switching operation of the second and third opening / closing means is repeated, and the first power converter and the second power converter. It changes the DC input voltage of the vessel.

According to a fifteenth aspect of the present invention, the AC power supply device repeats the opening / closing operation of the first opening / closing means when the second and third opening / closing means are in the open state, or when the first opening / closing means is in the open state, The switching operation of the second and third switching means is repeated to change the DC input voltage of the first and second power converters.

According to another aspect of the present invention, when the voltage command to the first and second power converters exceeds a predetermined value, the first and second power converters are driven in parallel. A switching signal output means for outputting a switching signal to the first to third opening / closing means so as to drive the first and second power conversion means in series when the voltage command becomes equal to or less than a predetermined value; Voltage command output means for setting the voltage command to the first and second power converters to a value twice as large as the original voltage command and outputting the voltage command when the voltage command falls below a predetermined value.

The AC power supply device according to claim 17, wherein at least when the first and second power conversions are connected in series or in parallel, the modulation rate is fixed and the first and second power conversion means are provided. Is provided with a driving means for performing PWM driving.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an inverter device as an AC power supply device according to the present embodiment. In the figure, reference numeral 1 denotes a battery, and 2 denotes a first inverter as first AC power conversion means configured by connecting six transistors in a three-phase bridge connection.

The first inverter 2 comprises a pair of series-connected transistors connected between the DC positive input 21 of the battery 1 and the DC negative input 22 of the battery 1 via the second switch 7. the qu ₁₁ -qu _12, another pair of transistors Qv ₁₁ -qv ₁₂ which are connected in series, the transistor Qw ₁₁ -qw ₁₂ is configured by parallel connection, respectively.

Reference numeral 3 denotes a second inverter as second AC power conversion means similarly constituted by connecting six transistors in a three-phase bridge. The second inverter 3 is a pair of series-connected transistors Qu ₂₁ -Qu connected between the DC positive input 31 of the battery 1 and the DC negative input 32 of the battery 1 via the third open / close switch 8.
₂₂ , another pair of transistors Qv ₂₁ −
Qv ₂₂ and Qw ₂₁ −Qw ₂₂ are connected in parallel.

The DC negative input side 22 of the first inverter 2
Is connected to the DC positive input side 31 of the second inverter 3 by the first open / close switch 6 so as to be able to contact and separate therefrom. still,
The first on / off switch 6, the second on / off switch 7, and the third on / off switch 8 constitute a series / parallel connection switching unit. A commutating diode D is connected in anti-parallel between the collector and the emitter of each transistor constituting the three-phase bridge.

Reference numeral 4 denotes two primary windings connected in Y-Y and 1
A three-phase transformer as a power combining means having two secondary windings, and the first primary winding includes a U-phase output terminal, a V-phase output terminal, and a W-phase output terminal of the first inverter 2. 1 input terminal 4
1 are connected.

The U-phase output terminal, V-phase output terminal, and W-phase output terminal of the second inverter 3 are connected to the second primary winding.
Are connected via an input terminal 42 of the. A motor 5 as an AC motor is connected to the secondary winding via an output terminal 43.
Are connected.

Next, the operation of this embodiment will be described. First, in the region where the number of rotations (frequency) is low when the motor 5 is started, the first opening / closing switch 6 is closed and the second and third opening / closing switches 7 and 8 are opened based on a detection signal of rotation detection means (not shown). Thus, the first inverter 2 and the second inverter 3 are connected in series. As a result, the first inverter 2
And the DC input voltage of the second inverter 3 is the battery 1
Of the voltage. In this state, when the first inverter 2 and the second inverter 3 operate, the outputs of the inverters 2 and 3 are combined by the three-phase transformer 4 and
Input to phase winding.

When the inverters are connected in series, the DC input voltage of the first inverter 2 and the second inverter 3 becomes １ ／, and the output voltage of each of the inverters 2 and 3 also becomes 最大. Is driven with low electromotive force when is low. However, since the DC input voltage of the first inverter 2 and the second inverter 3 is low, the modulation rate of each of the inverters 2 and 3 can be doubled as compared with the conventional case. Therefore, the ratio of the harmonic voltage to the output waveforms of the first inverter 2 and the second inverter 3 is reduced, and there is an effect that the loss due to the harmonic current can be reduced.

Next, when the number of revolutions of the motor 5 increases, the first speed is determined based on a detection signal of a rotation detecting means (not shown).
Open switch 6, and the second and third open / close switches 7,
8 to close the first inverter 2 and the second inverter 3
Are connected in parallel. As a result, the DC input voltage of each of the inverters 2 and 3 becomes the voltage of the battery 1 itself. Therefore,
A voltage equivalent to that of the related art can be obtained, and a sufficient inverter output voltage can be obtained even in a high-speed rotation region where the back electromotive force of the motor 5 is large.

In the above embodiment, two inverters 2
Although the configuration in which the output of 3 is synthesized by the three-phase transformer 4 is shown,
The outputs of the two inverters may be used to drive two different motors.

Embodiment 2 Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a configuration diagram of the inverter device according to the present embodiment. In the drawing, the same or corresponding portions as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. In the inverter device according to the present embodiment, the third opening / closing switch 8 is omitted from the inverter device shown in FIG. 1, the cathode is on the DC positive input side of the first inverter 2, and the anode is the DC positive input of the second inverter 3. Connected to the side. In this configuration, the DC positive terminal 31 of the second inverter is always connected to the positive terminal of the battery 1.

Therefore, the first open / close switch 6 is closed,
When the open / close switch 7 is open, the operation of the first inverter 2
And the second inverter 3 are connected in series, and perform the same inverter control operation as in the first embodiment.

Now, when the second switch 7 is closed and the first switch 6 is open, the second switch 9
The application of the battery voltage to the inverter 3 is prevented, so that only the first inverter 2 is connected to the battery 1 by the second open / close switch 7 and the battery 1 is not connected to the second inverter 3. When the first inverter 2 is operated in this state, the motor 5 is driven only by the first inverter 2.

However, at the time of high-speed rotation, a high voltage is required and the current may be small. Therefore, it is not particularly necessary to increase the current capacity of the switching element of the inverter.
In this way, the open / close switch can be constituted by two first and second open / close switches 6 and 7. When the second open / close switch 7 is opened, the voltage generated by the second inverter 3 can be regenerated to the battery 1 by the diode 9.

Embodiment 3 In the first and second embodiments, the output voltages of the first and second inverters 2 and 3 are combined by the three-phase transformer 4 and supplied to the motor 5, but this embodiment is equivalent to the circuit diagram of FIG. As shown, the motor 5 is provided with first three-phase windings 51a, 51b, and 51c connected in a Y-connection, and second three-phase windings 52a, 52b, and 52c connected in the same manner in the same slot. ing.

The first three-phase windings 51a, 51b,
51c is the first inverter 2 via the first input terminal 41.
, And the second three-phase windings 52 a, 52
b and 52c are connected to the three-phase output of the second inverter 3 via the second input terminal 42.

That is, the three-phase output of the first inverter 2 and the three-phase output of the second inverter 3 are combined in a stator slot inside the motor 5, and as a result,
The three-phase transformer 4 becomes unnecessary. FIG. 4 shows an example of each three-phase winding. The figure shows an example of all-knot winding when the number of slots per pole is twelve. In the figure, U1, V1, and W1 are first three-phase windings, and U2, V2, and W2 are second three-phase windings, which are wound in the same slot as the first three-phase winding.

As in the first embodiment, the motor control operation of the inverter device is similar to that of the first embodiment when the first open / close switch 6 is closed and the second and third open / close switches 7 and 8 are open. 2 inverters 3 are connected in series, and the first inverter 2 and the second inverter 3
Is 1/2 of the voltage of the battery 1
Voltage.

In this state, when the first inverter 2 and the second inverter 3 operate, the outputs of the inverters 2 and 3 output the first three-phase windings 51a, 51b and 51c inside the motor 5, respectively.
The motor 5 is driven by the second three-phase windings 52a, 52b, and 52c. At this time, since the DC input voltage of each of the inverters 2 and 3 is halved,
Of the motor 5 is driven at a low starting voltage when the rotation speed of the motor 5 is low. However, since the applied DC input voltage is low, the modulation factor of each of the inverters 2 and 3 is lower than that in the conventional case. Can be twice as large.

Accordingly, the ratio of the harmonic voltage to the output voltage form of each of the inverters 2 and 3 is reduced, and the loss due to the harmonic current can be reduced. Further, since the output currents of the two inverters 2 and 3 are combined in the motor 5, the current capacity of the switching element of each of the inverters 2 and 3 may be １ ／ that of a single inverter device. The current capacity of the total switching elements can be the same.

Next, the first open / close switch 6 is opened,
When the third on / off switches 7 and 8 are closed, the first inverter 2 and the second inverter 3 are connected in parallel, and the DC input voltage of each of the inverters 2 and 3 becomes the voltage of the battery 1 itself. Therefore, an output voltage that is twice as high as that obtained when the first inverter 2 and the second inverter 3 are connected in series is obtained, and a sufficient inverter output voltage is obtained even in a high-speed rotation region where the back electromotive force of the motor 5 is large.

Further, as shown in FIG.
Is omitted, and the inverter device is configured in the same manner as in the second embodiment. The first open / close switch 6 is closed and the second open / close switch 7 is opened at a low speed, and the first open / close switch 6 is opened at a high speed. Alternatively, the second open / close switch 7 may be closed.

In this case, at high speed, the first three-phase winding 51
Since the current flows only through the switches a, 51b, and 51c, the efficiency of the motor 5 is slightly reduced. However, two switches can be used. Further, since the voltage is doubled at high speed, the output current of the inverter may be reduced to half, so that even if the motor 5 is driven by one inverter, it is not necessary to increase the current capacity of the switching element of the inverter.

Embodiment 4 FIG. 6 is a block diagram for explaining the concept of PWM waveform generation according to the fourth embodiment of the present invention. Reference numeral 101 denotes a triangular wave transmitter for transmitting a triangular wave as a carrier wave, and 102 denotes a triangular wave based on a voltage command of an inverter (not shown). A three-phase voltage generator for generating a three-phase reference voltage having, for example, a sine wave having an amplitude value;
Numeral 5 denotes a triangular wave as a carrier wave input from a triangular wave oscillator 101 to one input terminal, and a three-phase reference voltage generated from a three-phase voltage generator 102 to the other input terminal to input the amplitude of the triangular wave and the three-phase reference. A comparator 106 for comparing the voltage with the amplitude is an inverter for inverting the logic level of the triangular wave generated by the triangular wave transmitter 101 and outputting the inverted signal.

Each of the input terminals 107 to 109 receives a triangular wave generated from the triangular wave oscillator 101 and having its logic level inverted by an inverter at one input terminal, and a three-phase voltage generated from the three-phase voltage generator 102 at the other input terminal. This comparator receives a reference voltage and compares the amplitude of the triangular wave with the amplitude of the three-phase reference voltage.

FIGS. 7 (a) to 7 (e) show voltage waveforms for explaining the PWM waveform generating operation, and show only a waveform for one phase. In FIG. 3A, when a three-phase reference voltage 111 is generated from a three-phase voltage generator 102 and a triangular wave (modulation voltage) 110 is output from a triangular wave oscillator 101 and input to comparators 103 to 105, each amplitude Are compared.

In the comparators 103 to 105, a pulse train 112 whose level becomes H every time the amplitude of the triangular wave 110 is lower than the amplitude of the three-phase reference voltage 111 is output as a PWM modulated wave as shown in FIG. This pulse train waveform is used as an ON signal of an upper-arm transistor in a first inverter 2 (see FIG. 1) not shown, and an inverted version of this pulse waveform is used to turn on a transistor in a lower arm of the first inverter 1 (not shown). First signal
Is driven.

In FIG. 3B, a three-phase reference voltage 114 is generated from the three-phase voltage generator 102, and
6 outputs a triangular wave (modulated voltage) 113 obtained by inverting the triangular wave from the triangular wave transmitter 101,
When the amplitudes are input to １０９109, the respective amplitudes are compared.

In the comparators 107 to 109, a pulse train 115 whose level becomes H every time the amplitude of the triangular wave 113 is lower than the amplitude of the three-phase reference voltage 114 is output as a PWM modulated wave as shown in FIG. The pulse-on waveform of the upper-arm transistor in the second inverter 3 (see FIG. 1) not shown is replaced with the transistor-on signal of the lower arm of the second inverter 3 (not shown). To drive the second inverter 3.

When, for example, the two inverters shown in FIG. 3 are driven by the two PWM waveforms generated in this way, the combined waveform becomes the pulse waveform 116 shown in FIG.
become that way. This means that the frequency of the harmonic is about twice that of a single inverter driven by PWM.

As a result, the reactance of the motor 5 with respect to the harmonics is also doubled, so that the harmonic current is reduced, the copper loss due to the harmonic current is reduced, and the efficiency of the motor 5 is improved. Furthermore, since the inverter output waveform is synthesized inside the motor 5, a reactor or the like is not required.

In this embodiment, an example of an inverter device capable of switching the first and second inverters 2 and 3 in series / parallel has been described. However, if the output of the two inverters is combined, it is not necessary to switch the two inverters in series / parallel with an open / close switch, and the motor 5 combines the outputs of the two inverters connected in parallel or series in advance. The same effect as described above can be obtained by forming the motor drive waveform.

Further, as shown in FIG. 4, in an inverter device configured to switch between two inverters connected in series or to use only a single inverter, a case where only a single inverter is used is used. Is the same as the conventional one, but has the same effect as described above when connected in series.

Embodiment 5 Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a configuration diagram of the motor according to the present embodiment. In the figure, the same or corresponding parts as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.
The motor 5 in the present embodiment has a first three-phase winding 51
a, 51b, 51c and second three-phase windings 53a, 53
b and 53c are wound around the same stator with an electrical angle shifted by π / 6 spatial phase. FIG. 9 shows an example of the winding. The figure shows an example of a full section winding with 12 slots per pole.

In FIG. 9, U, V and W are first windings,
R, S, and T correspond to the second winding. Further, the first inverter 2 and the second inverter 3 have a phase shift of π / 6.
Outputs a phase AC waveform. Therefore, the motor 5 is the same as the one driven by the 12-phase AC voltage, and the first and second windings are different from those of the conventional example in which the phases of the outputs of the inverters 2 and 3 are simply shifted. In addition, by shifting the spatial phase, the fundamental wave can be prevented from lowering, spatial harmonics can be reduced, torque ripple can be suppressed, and harmonic loss can be reduced.

In this embodiment, an example is shown in which the two first and second inverters 2 and 3 can be switched in series and parallel by the first and third on / off switches 6 and 8.
If the outputs of the two inverters are combined, it is not necessary to switch between series and parallel by the first and third on / off switches 6 and 8 in particular. The first three-phase windings 51a, 51b, 51c and the second three-phase windings 53a, 53c of the motor 5 are used as drive waveforms of two inverter outputs connected in parallel or in series in advance.
The same effects as described above can be obtained even when the signals are output to 3b and 53c and combined.

Embodiment 6 FIG. Hereinafter, Embodiment 6 of the present invention will be described with reference to the drawings. FIG. 10 is a configuration diagram of the motor according to the present embodiment. In the drawing, the same or corresponding parts as those in FIG. 8 are indicated by the same reference numerals, and detailed description thereof will be omitted. In the motor 5 in the present embodiment, the first three-phase windings 51a, 51b, 51c and the first three-phase windings 51a, 51b, 51c connected in Y form a π / 6 spatial phase in electrical angle. There are second three-phase windings 54a, 54b, 54c wound around the same stator and shifted by Δ.

FIG. 11 shows an example of the winding. The figure shows an example of all-knot winding when the number of slots per pole is twelve. In the figure, U, V, and W indicate a first three-phase winding connected in Y, and R, S, and T indicate a second three-phase winding connected in Δ. That is, a 12-phase AC voltage is generated by shifting the phase of the voltage applied to each slot around which each winding is wound by Y connection and Δ connection by π / 6 and shifting the slot arrangement by π / 6. A driving system equivalent to a 12-phase alternating current has been obtained. By doing so, the spatial harmonic magnetomotive force is reduced, which is effective in suppressing the torque ripple of the motor 5 and reducing the harmonic loss.

The first three-phase winding 51 connected in a Y-connection
a, 51b, and 51c and the second 3
The winding ratio of the phase windings 54a, 54b, 54c is approximately 1: √3
By doing so, it is possible to balance the electromotive force of the Y connection and the electromotive force of the Δ connection, and reduce an increase in loss due to circulating current.

Further, the first three-phase windings 51a, 51b, 51c and the second three-phase winding 54
a, 54b and 54c can reduce the spatial harmonics with a single conventional inverter.

Embodiment 7 FIG. Hereinafter, a seventh embodiment of the present invention will be described with reference to the drawings. FIG. 12 is a configuration diagram of the motor according to the present embodiment. In the drawing, the same or corresponding parts as those in FIG. 10 are denoted by the same reference numerals, and detailed description thereof will be omitted. The motor 5 of the present embodiment has a first three-phase winding 51
a, 51b, and 51c are Y-connected, and the first three-phase winding 51
a, 51b, and 51c are second three-phase windings 54 wound around the same slot with the spatial phase shifted by π / 6 in electrical angle.
a, 54b, 54c are Δ-connected, and the second three-phase winding 54
a, 54b, 54c are connected to the first three-phase windings 51a, 51a,
Along with the three-phase ends of 51b and 51c,
It is connected to the phase output via a first input 41.

Further, the motor 5 has a first three-phase winding 51
a, 51b, and 51c are third three-phase windings 55 wound around the same slot with a spatial phase shifted by π / 12 in electrical angle.
a, 55b, and 55c are Y-connected, and the third three-phase winding 55
a, 55b and 55c are fourth three-phase windings 56 wound around the same slot with the spatial phase shifted by π / 6 in electrical angle.
a, 56b, 56c are Δ-connected. The three-phase ends of the fourth three-phase windings 56a, 56b, 56c are connected to the third three-phase winding 5
Along with the three-phase terminals of 5a, 55b, and 55c, they are connected to the three-phase output terminal of the second inverter 3 via the second input terminal 41.

First to fourth three-phase windings 51a, 51
b, 51c, 54a, 54b, 54c to 56a, 56
FIG. 13 shows examples of windings b and 56c. The figure shows an example of all-knot winding when the number of slots per pole is twelve.
In the figure, U1, V1, and W1 are Y-connected first 3
The phase windings, R1, S1, and T1, are Δ-connected second three-phase windings and are wound with a spatial phase shifted by π / 6 from the first three-phase winding. First three-phase windings U1, V1, W
1 connected.

U2, V2, and W2 are Y-connected third three-phase windings having a spatial phase of π / 12 with respect to the first three-phase winding.
R2, S2, and T2 are shifted by Δ and
Is wound with a spatial phase shifted by π / 6 from that of the third three-phase winding, and the three-phase end of the Δ connection is connected to the third three-phase winding U2.
V2 and W2.

First inverter 2 and second inverter 3
By shifting the phase of the three-phase AC output by π / 12, the motor 5 is driven by the 24-phase AC voltage, so that it is possible to greatly reduce spatial harmonics and suppress torque ripple.

First inverter 2 and second inverter 3
The switch may be switched between series and parallel by the open / close switches 6, 7, and 8. Alternatively, the open / close switch 8 may be omitted, and an inverter may be used in series or alone, or may be fixed in advance to a series connection or a parallel connection.

Alternatively, the Y-connected windings 51a, 51b, 5
1c, 55a, 55b, 55c and Δ-connected windings 54a,
By setting the ratio of the number of turns to 54b, 54c, 56a, 56b, 56c to about 1: √3, the loss due to the circulating current can be reduced.

Embodiment 8 FIG. Hereinafter, an eighth embodiment of the present invention will be described with reference to the drawings. FIG. 14 is a configuration diagram of the inverter device according to the present embodiment. In the drawing, the same or corresponding portions as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. In FIG. 14, 1 is a battery, 2 is a first inverter connected in a three-phase bridge, and a DC positive input side 21 is connected to the positive electrode of the battery 1. Reference numeral 3 denotes a second inverter also connected in a three-phase bridge, and the DC negative input side 32 is connected to the negative electrode of the battery 1.

The DC negative input side 22 of the first inverter 2
Is connected to the DC positive input 31 of the second inverter 3 by the diode 6 and is connected to the DC negative input 22 of the first inverter 2 and the DC negative input 3 of the second inverter 3.
2 (the negative electrode of the battery 1), the collector and the emitter of the transistor 71 are connected.
The transistor 8 is connected between the DC positive input side 21 (the positive electrode of the battery 1) and the DC positive input side 31 of the second inverter 3.
1 are connected to the collector and the emitter.

Reference numeral 4 denotes a two-input, one-output three-phase transformer. The first input terminal 41 is at the output terminal of the first inverter 2, the second input terminal 42 is at the output terminal of the second inverter, The output terminal 43 is connected to the three-phase winding of the motor 5.

Next, the operation of this embodiment will be described. First, when the transistor 71 and the transistor 81 are turned off and the first inverter 2 and the second inverter 3 are connected in series, a voltage of バ ッ テ リ of the battery voltage is applied to the first inverter 2 and the second inverter 3. , First
Output voltage of the inverter 2 and the second inverter 3 can be set low. As a result, a desired voltage can be obtained at a high modulation rate, and the content of the harmonic voltage is reduced, so that the loss of the inverter output due to the harmonic can be reduced. Outputs of the first inverter 2 and the second inverter 3 are combined by a three-phase transformer 4 to drive a motor 5.

The operation during regeneration of the motor 5 will be described. When the motor 5 is driven from the outside to generate power, a regenerative voltage is generated at the DC input terminals of the first inverter 2 and the second inverter 3 through the three-phase transformer 4. At this time, the regenerative voltage of the first inverter 2 is regenerated and charged into the battery 1 through the diode 72 connected in parallel with the transistor 71. The regenerative voltage of the second inverter 3 is regenerated and charged in the battery 1 through a diode 82 connected in parallel with the transistor 81.

Next, the transistor 71 and the transistor 8
When the first inverter 2 is turned on, the voltage of the battery 1 passes through the first inverter 2 and the transistor 71, and passes through the second inverter 3 and the transistor 81.
And the second inverter 3 are connected in parallel.
Therefore, the DC input voltage of the first inverter 2 and the DC input voltage of the second inverter 3 are both the voltage of the battery 1 itself, and a voltage twice as high as that when the inverters 2 and 3 are connected in series is applied.

The operation at the time of regeneration at this time is also the same.
The regenerative voltage of the first inverter 2 is regenerated by the battery 1 through the diode 72 and charged. Further, the regenerative voltage of the second inverter 3 is regenerated by the battery 1 through the diode 82 and charged.

At this time, in the present embodiment, the three-phase transformer 4
, The output of the first inverter 2 and the output of the second inverter 3 are combined to drive the motor 5. However, the three-phase transformer 4 is omitted, and as shown in FIG. The outputs of the inverter 2 and the second inverter 3 may be combined.

Further, when the inverters 1 and 2 are PWM inverters, the phases of the carrier wave for the first inverter 2 and the carrier wave for the second inverter 3 when generating the PWM signal are shifted by π, The output of No. 3 may be shifted by π.

Further, the spatial phases of the first three-phase winding and the second three-phase winding of the motor 5 are shifted by π / 6 in electrical angle, and the three phases of the first inverter 2 and the second inverter 3 are changed. Output phase π
The motor 5 may be driven by a 12-phase AC voltage corresponding to the 12-phase AC voltage by shifting the voltage by / 6.

Further, when the inverters 2 and 3 are connected in series,
That is, when the transistors 71 and 81 are off, the first inverter 2 and the second inverter 3 are PWM-driven. When the inverters 2 and 3 are connected in parallel, that is, when the transistors 71 and 81 are on, the first A PA that adjusts the DC input voltage of the first inverter 2 and the second inverter 3 by energizing the inverter 2 and the second inverter 3 by 120 degrees and opening and closing the transistors 71 and 81.
M driving may be performed.

In this manner, when the rotation frequency region of the motor 5 is low and the electromotive force of the motor is small, the first and second inverters 2 and 3 are connected in series to perform PWM driving, thereby achieving low-order driving. High efficiency operation with small harmonics of In a high frequency region where the electromotive force of the motor 5 is high, a high drive voltage is obtained by connecting the first and second inverters 2 and 3 in parallel, and the switching of the first and second inverters 2 and 3 is performed. Since the frequency can be lowered, a low-cost switching element having a low operation speed can be used as the switching element used in the first and second inverters 2 and 3.

If the spatial phases of the two primary windings of the motor 5 are shifted by π / 6 in electrical angle and the three-phase output phases of the first and second inverters 2 and 3 are shifted by π / 6, When the first and second inverters 2 and 3 are driven by PAM, time harmonics of the motor due to PAM driving can also be reduced, and efficient operation can be performed.

When the transistors 71 and 8 are connected in parallel,
1 to open and close the first and second inverters 2 and 3
The first and second inverters 2 and 3 may be PWM driven while controlling the DC input voltage of the first and second inverters. By driving in this manner, the motor 5 can be driven in a state where the modulation rates of the first and second inverters 2 and 3 are high, so that the content of harmonics is reduced, and the motor can be operated with high efficiency.

In the above embodiment, an example is shown in which a transistor is used as a series / parallel switch. However, another semiconductor switching element such as a MOSFET or an IGB
T or the like may be used.

Embodiment 9 Hereinafter, a ninth embodiment of the present invention will be described with reference to the drawings. FIG. 16 is a configuration diagram of the inverter device according to the present embodiment. In FIG. 15, FIG.
The same reference numerals as those of the first embodiment denote the same or corresponding parts, and a detailed description thereof is omitted. In the inverter device according to the present embodiment, a transistor 62 is connected in parallel to a diode 61 in the ninth embodiment shown in FIG. The transistor 62 is turned on when the first and second inverters 2 and 3 are used in series connection.

When the motor 5 is driven, the operation is the same as that of the eighth embodiment described above, so that it is not always necessary to turn on the transistor 62. If the transistor 62 is turned on when the motor 5 is driven from the outside and performs a regenerative operation, the voltage of the first inverter 2 and the voltage of the second inverter 3 are connected in series through the transistor 62 and the battery 1 , The regenerative operation becomes easy even at the time of low-speed rotation where the back electromotive force of the motor 5 is small.

Embodiment 10 FIG. Hereinafter, a tenth embodiment of the present invention will be described with reference to the drawings. FIG. 17 is a configuration diagram of the inverter device according to the present embodiment. In the drawing, the same or corresponding parts as those in FIG. 16 are indicated by the same reference numerals, and detailed description thereof will be omitted. The inverter device of this embodiment is different from the embodiment of FIG. 16 in that a transistor 63 is added in series with a diode 61 and a diode 64 is added in series with a transistor 62.

The connection relationship between the diodes 61 and 64 and the transistors 62 and 63 is as follows.
The cathode of the diode 61 whose anode is connected to the DC negative input side 22 is connected to the collector of a transistor 63 whose emitter is connected to the DC positive input side 31 of the second inverter 3.

The anode of a diode 64 whose cathode is connected to the DC negative input side 22 of the first inverter 2 has a collector connected to the DC positive input side 3 of the second inverter 3.
It is connected to the emitter of the transistor 64 which is connected to 1.

First, the first and second inverters 2 and 3
The operation at the time of parallel driving will be described. Transistors 62 and 6
3 is turned off, and the transistors 71 and 81 are opened and closed to change the DC input voltage of the inverters 2 and 3, thereby performing PAM control on the inverters 2 and 3.

The operation in series when the first and second inverters 2 and 3 are driven in parallel includes transistors 71 and 8
1 is turned off and the transistors 62 and 63 are turned on.
The DC input voltage of the first inverter 2 and the second inverter 3 can be adjusted by opening and closing the transistor 62. The first and second inverters 2 and 3 are PAM
Since they can be driven, the switching elements of the first and second inverters 2 and 3 have a low operating speed and are inexpensive and can withstand use sufficiently.

In series operation, the transistor 63 is opened and closed, and in parallel operation, the transistors 71 and 81 are opened and closed to control the DC input voltage of the first and second inverters 2 and 3 and the first and second inverters. PWM for a few
If controlled, the PWM modulation rate can be used in a high state, so that the harmonic content is reduced and the efficiency of the motor 5 is improved.

Embodiment 11 FIG. FIG. 18 shows a series / parallel connection switching signal of first and second inverters 2 and 3 according to the present embodiment and first and second inverters 2 and 3.
3 is a configuration diagram of a signal generation circuit as a switching signal output unit that issues a voltage command signal of No. 3; FIG. This signal generating circuit is provided in the first open / close switch 6 and the second open / close switch 7, 8 in the first, second, third, fifth or seventh embodiment, or in the transistors 62, 63, 7
H, L as series connection / parallel connection switching signals
Used when generating a level signal. Note that the reference voltage is set to a value that is の of the maximum voltage that can be output by the first and second inverters 2 and 3. Here, the voltage command is a DC value corresponding to a desired sine wave amplitude.

In FIG. 18, the comparator 201 outputs +
A voltage command corresponding to the drive control of the motor is input to the input terminal, and a preset reference voltage is input to the-input terminal. When the voltage command value is higher than the reference voltage, the comparator 201 outputs an H-level parallel connection switching signal so that the inverters 2 and 3 are connected in parallel and the battery voltage is applied to the inverters 2 and 3 as they are. . When the voltage command value is lower than the reference voltage, the L level signal is inverted to the H level by the inverter 202 so as to output a series connection switching signal so that the inverters 2 and 3 are connected in series.

The output of the comparator 201 is the same as that of the first embodiment.
In the case of the inverter device described above, the signal is branched and output to the first open / close switch 6 through the second and third open / close switches 7, 8 and the inverter 207.

The comparator 201 outputs an H level parallel connection switching signal as a strobe signal in the analog buffer 2.
When the voltage command is input to the three-phase voltage generator 103, the voltage command input to the comparator 201 is input to the three-phase voltage generator 102 shown in FIG. 6 through the analog buffer 203 as a voltage command for the first and second inverters 2 and 3. Although the voltage of the triangular wave is inverted by the inverter 106 in FIG. 6, the inverter 106 is not always required in this embodiment.

If the voltage command is lower than the reference voltage, the L level signal is input from the comparator 201 to the analog buffer 204 as a negative strobe signal, and the voltage doubled by the multiplier 205 as voltage command output means. The command is input to the three-phase voltage generator 102 shown in FIG. 6 as a voltage command for the first and second inverters 2 and 3 through the analog buffer 204.

In the above-described circuit configuration, the value of the voltage command is compared with the reference voltage by the comparator 201. If the value is higher than the reference voltage, the first and second inverters 2, 3
Are connected in parallel, an H level parallel connection switching signal is output.

As a result, if the inverter device has the configuration shown in FIG. 1, for example, the H-level parallel connection switching signal is input to the second switch 7 and the third switch 8 by the comparator 201. , The second and third on / off switches 7 and 8 are turned on to connect the first inverter 2 and the second inverter 3 to the battery 1 in parallel.

The first open / close switch 6 is connected to the inverter 2
At 02, the signal is inverted to the L level and a signal is input, so that the transistor is turned off. As a result, the first inverter 2 and the second inverter 3 are connected in parallel by the second and third open / close switches 7 and 8 that are turned on. Comparator 201
Are input from the analog buffer 203 to the three-phase voltage generator 102 as voltage command values for the first and second inverters as they are.

When the voltage command value is lower than the reference voltage, the comparator 201 outputs an L level signal.

Then, the second and third open / close switches 7,
Since the L level signal is input to each of the second and third signals, the second
And the third open / close switches 7, 8 are turned off. Further, since the signal inverted to the H level by the inverter 202 is input to the first open / close switch 6, the first open / close switch 6 is turned on. As a result, the first inverter 2
And the second inverter 3 are connected in series by the first open / close switch 6 which is turned on.

When an L-level signal is input from the comparator 201 to the strobe terminal of the analog buffer 204, the tri-state buffer 204 outputs the voltage command doubled by the multiplier 205 to the voltage command of the first inverter 2, To the three-phase voltage generator 102 as a voltage command for the inverter 3.

That is, when the inverters 2 and 3 are connected in series, the DC input voltage of each of the inverters 2 and 3 is halved, so that the voltage command value of the inverters 2 and 3 is doubled to actually output. To make the applied voltage equal to the original voltage command value. In this way, a required voltage is always obtained from inverters 2 and 3 and inverters 2 and 3
, The modulation rate is kept high at all times, and the harmonics are kept to a minimum so that efficient motor operation can be performed.

Embodiment 12 FIG. FIG. 19A shows an example in which the first and second inverters of the inverter device shown in FIG. 16 are connected in parallel or the first and second inverters are connected in series. This is a switching control circuit suitable for adjusting a DC input voltage to be applied.

As a configuration of this circuit, the comparator 20
1 outputs an H level signal to the strobe terminal of the tri-state buffer 309 when the voltage command input to the + input terminal becomes higher than the reference voltage previously input to the-input terminal. Here, the voltage command is a DC value corresponding to the amplitude of the desired sine wave voltage. When the voltage command becomes lower than the reference voltage, the L level signal is inverted to an H level signal by the inverter 202 and output to the strobe terminal of the tri-state buffer 301.

When an H level signal is input from the comparator 201 to the strobe terminal of the tri-state buffer 309, the comparator 307 at the preceding stage outputs a triangular wave generator 306.
, And a PWM signal as a comparison result with the voltage command are input to the bases of the transistors 71 and 81 through the tri-state buffer 309 as a switching signal.

When an H level signal is input from the inverter 202 to the strobe terminal of the tri-state buffer 310, the triangular wave generator 306 is output from the comparator 308 in the preceding stage.
The PWM signal, which is the result of comparison between the triangular wave from and the voltage command doubled by the multiplier 205, is input to the base of the transistor 62 through the tri-state buffer 204 as a switching signal.

FIG. 19B shows drive means for generating a PWM signal to the first and second inverters 2 and 3 when the first and second inverters are connected in parallel or in series by a switching signal. Is a PWM signal generation circuit.

As a configuration of this circuit, the comparator 30
Reference numerals 3 to 305 denote a triangular wave from a triangular wave generator 301 and a three-phase sine wave generator 302 having an amplitude equal to the amplitude of the triangular wave.
, And outputs a PWM signal. Each of the comparators 303 to 305 inputs the output PWM signal to the base of a transistor in the upper arm of the first inverter 2 and the second inverter 3. Although not shown, the output PWM signal is inverted by an inverter, and
To the bases of the transistors in the lower arm of the second inverter 3 and the second inverter 3.

Next, the operation of the present embodiment will be described using the inverter device shown in FIG. 16 as an example. First, when the voltage command for determining the output voltage of the inverter becomes higher than the reference voltage, the comparator 201 inputs an H level signal to the strobe terminal of the tri-state buffer 309, and inputs the PWM signal of the comparator 307 to the bases of the transistors 81 and 71. Then, the first and second inverters 2 and 3 are connected in parallel while performing the opening and closing operation.

Since the transistors 81 and 71 repeat opening and closing operations in accordance with the pulse rate of the PWM signal, the battery voltage input to each of the first and second inverters 2 and 3 connected in parallel is adjusted. At this time, since the first and second inverters 2 and 3 are controlled by the PWM signal from the PWM signal generating circuit, the modulation rate of the sine wave PWM is always 1, and the motor operation with less harmonics and high efficiency is performed. It can be carried out.

When the voltage command falls below the reference voltage, the comparator 201 outputs an L level signal. This signal is inverted to an H level signal by the inverter 202 and input to the strobe terminal of the tristate buffer 310, and the PWM signal of the comparator 308 is output to the transistor 6
The first and second inverters 2 and 3 are connected in series while inputting and opening / closing the input to the base of the first inverter.

Since the transistor 61 repeats opening and closing operations in accordance with the pulse rate of the PWM signal, the average value of the battery voltage input to each of the first and second inverters 2 and 3 connected in series is adjusted. Therefore, the required voltage is always obtained from the first and second inverters 2 and 3.

At this time, the first and second inverters 2,
3 is controlled by the PWM signal from the PWM signal generating circuit, so that the modulation rate of the sine wave PWM is always 1, and the harmonics are reduced, so that efficient motor operation can be performed.

In each of the above embodiments, the first to third open / close switches 6, 7, 8 or the transistor 61 are connected so that two inverters such as the first and second inverters 2 and 3 are connected in series and parallel. To 81 were provided. However, the number of inverters connected in series / parallel is not limited to two, and may be two or more. In this case, the number of on / off switches or transistors is increased as the number of inverters is increased, and a plurality of inverters are connected in series / parallel. On / off operation.

[0118]

According to the present invention, at least two power conversion means for converting DC power into AC power and supplying the AC power to a load, and connecting these electrode conversion means in series between the positive electrode of the DC power supply and the negative electrode of the DC power supply or Series-parallel connection switching means for switching to parallel connection with respect to the power supply; and power combining means for combining the outputs of the plurality of power conversion means connected in series or in parallel by the series-parallel connection switching means and supplying the combined output to a load. With this arrangement, the ratio of the harmonic voltage to the output waveform of the power converter is reduced, and the loss due to the harmonic current can be reduced.

According to the present invention, the series-parallel connection switching means includes a DC input terminal having one DC input terminal connected to the positive electrode of the DC power supply, and a DC input terminal having the other DC input terminal connected to the DC power supply positive electrode. A first opening / closing means connected to the other DC input terminal of the second AC power conversion means connected to the power supply negative electrode so as to be openable and closable, and the other DC input terminal of the first AC power conversion means A second switching means connected between the DC power supply negative electrode and the DC power supply negative electrode, and a third switching means connecting the other DC input terminal of the second AC power conversion means to the DC power supply positive electrode so as to be openable and closable. As a result, the ratio of the harmonic voltage to the output waveform of the power converter is reduced, and the loss due to the harmonic current can be reduced. effective.

According to the present invention, the series-parallel connection switching means includes a DC input terminal having one DC input terminal connected to the positive electrode of the DC power supply, and a DC input terminal having the other DC input terminal connected to the DC power supply positive electrode. A first opening / closing means connected to the other DC input terminal of the second AC power conversion means connected to the power supply negative electrode so as to be openable and closable, and the other DC input terminal of the first AC power conversion means And a second switching means connected between the DC power supply negative electrode and the DC power supply negative electrode, and a connection means for connecting the other DC input terminal of the second power conversion means to the DC power supply positive electrode. This has the effect of reducing the number and simplifying the configuration of the device.

According to the present invention, the connecting means is a diode whose cathode is connected to the positive electrode of the DC power supply and whose anode is connected to the other DC input terminal of the second power converting means. There is an effect that the regenerative power of the AC power conversion means can be easily returned to the DC power supply.

According to the present invention, a plurality of three-phase windings are electrically insulated and wound on the armature, and the AC power generated by each AC power generator is input to each of the three-phase windings. In this case, the transformer can be omitted, so that the apparatus can be reduced in size and cost can be reduced.

According to the present invention, each three-phase winding is electrically insulated and wound around the armature in the same phase, so that the three-phase winding configuration can be simplified.

According to the present invention, each AC power generator is used as the first and second AC power converters, and the first and second PWM signals, which are the individual control signals for these AC power converters, are used. Since the phases of the first carrier and the second carrier generated respectively are shifted by π from each other, the harmonic frequency by the PWM signal is doubled, and the impedance of the load such as the motor with respect to the harmonic voltage is increased. Thus, the harmonic loss can be reduced.

According to the present invention, the first three-phase winding and the second
Since the three-phase winding is electrically insulated and wound around the armature with a phase shift of π / 6, there is an effect that spatial harmonics can be greatly reduced and torque ripple can be suppressed.

According to the present invention, the first three-phase winding wound three-phase around the armature is Y-connected, and the first three-phase winding is wound with an electrical angle π / 6 phase shifted therefrom. Since the turned second three-phase winding is △ -connected and the first and second three-phase windings are connected in parallel, there is an effect that a 12-phase alternating current is used and the spatial harmonics of the motor can be reduced.

According to the present invention, the first three-phase winding has the first
AC power is supplied from the AC power generator of
The AC power supplied from the first AC power generator to the three-phase winding and shifted by an electrical angle of π / 6 from the AC power is supplied to the second AC power generator.
Since the AC power generator is driven by supplying the AC power, a 12-phase AC is used, and there is an effect that spatial harmonics of the motor can be reduced.

According to the present invention, the first 3
Since the ratio of the number of windings of the phase winding to the number of windings of the 巻 線 -connected second three-phase winding is approximately 1: √3, the electromotive force of the Y-connection and the △ -connection can be well-balanced, and the circulation can be achieved. The current has the effect of reducing the increase in loss.

According to the present invention, the first three-phase winding and the first three-phase winding, which are three-phase wound around the armature and Y-connected, are wound with the electrical angle π / 6 shifted in phase. The second connected
Are connected in parallel with each other, and the first three-phase winding is shifted in phase by an electrical angle of π / 12, and the three-phase winding is connected in a Y-connection with the third three-phase winding. Since the fourth three-phase winding wound and shifted by an electrical angle of π / 6 from the three-phase winding is connected in parallel with the three-phase winding, spatial harmonics can be greatly reduced and torque ripple can be suppressed. This has the effect.

According to the present invention, AC power is supplied from the first AC power generator to the first and second three-phase windings connected in parallel, and the third and fourth three-phase windings are connected in parallel.
The AC power supplied from the first AC power generator and shifted from the AC power by an electrical angle π / 12 phase to the three-phase winding is supplied from the second AC power generator. Is driven by a 24-phase AC voltage, which has the effect of significantly reducing spatial harmonics and suppressing torque ripple.

According to the present invention, when the first opening / closing means is in the open state, the opening / closing operation of the second and third opening / closing means is repeated,
Since the DC input voltages of the first power converter and the second power converter are changed, a necessary voltage can always be obtained from the power conversion means, and the modulation rate of the power conversion means is always kept high and harmonics are maintained. There is an effect that efficient operation can be performed with the waves being minimized.

According to the present invention, the opening / closing operation of the first opening / closing means is repeated when the second and third opening / closing means are in the open state, or the second and third opening / closing operations are performed when the first opening / closing means is in the open state. The switching operation of the switching means is repeated to change the DC input voltage of the first and second power converters, so that the required voltage is always obtained from the power conversion means, and
There is an effect that efficient operation can be performed by keeping the modulation rate of the power conversion means always high and minimizing harmonics.

According to the present invention, when the voltage command to the first and second power conversion means exceeds a predetermined value, the first and second power conversion means are driven in parallel, and the voltage command is A switching signal output means for outputting a switching signal to the first to third opening / closing means so as to drive the first and second power conversion means in series when the voltage becomes equal to or less than a predetermined value; Voltage command output means for setting the voltage command to the first and second power converters to a value twice as large as the original voltage command and outputting the same when the value becomes equal to or less than the value. There is the effect that efficient operation can be performed by keeping the modulation factor of the power conversion means high at all times and minimizing harmonics.

According to the present invention, when at least the first and second power converters are connected in series or in parallel, the modulation factor is fixed at 1 and the first and second power converters are PWM driven. Since the driving means is provided, the operation can be performed efficiently with less harmonics.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an inverter device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an inverter device according to another embodiment of the present invention.

FIG. 3 is a circuit diagram showing a motor device according to another embodiment of the present invention.

FIG. 4 is a winding diagram showing a winding of a motor according to another embodiment of the present invention.

FIG. 5 is a circuit diagram showing a motor device according to another embodiment of the present invention.

FIG. 6 is a partial circuit diagram showing another embodiment of the present invention.

FIG. 7 is a timing chart showing the synthesis of a PWM waveform according to another embodiment of the present invention.

FIG. 8 is a circuit diagram showing a motor device according to another embodiment of the present invention.

FIG. 9 is a winding diagram showing windings of a motor according to another embodiment of the present invention.

FIG. 10 is a circuit diagram showing a motor device according to another embodiment of the present invention.

FIG. 11 is a winding diagram showing windings of a motor according to another embodiment of the present invention.

FIG. 12 is a circuit diagram showing a motor device according to another embodiment of the present invention.

FIG. 13 is a winding diagram showing windings of a motor according to another embodiment of the present invention.

FIG. 14 is a circuit diagram showing an inverter device according to another embodiment of the present invention.

FIG. 15 is a circuit diagram showing a motor device according to another embodiment of the present invention.

FIG. 16 is a circuit diagram showing a motor device according to another embodiment of the present invention.

FIG. 17 is a circuit diagram showing a motor device according to another embodiment of the present invention.

FIG. 18 is a circuit block diagram for generating a series / parallel switching signal and voltage commands for first and second inverters according to another embodiment of the present invention.

FIG. 19 is a circuit block diagram for generating a series / parallel switching signal and a voltage command for first and second inverters according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Battery, 2 1st inverter, 3 2nd inverter, 4 transformers, 5 motors, 6 1st on / off switch, 7 2nd on / off switch, 8 3rd on / off switch, 51a-51c 1st 3 Phase winding, 52a-52c
Second three-phase winding, 53a to 53c second three-phase winding,
54a to 54c second three-phase winding, 55a to 55c third three-phase winding, 56a to 56c fourth three-phase winding, 61
Diode, 62 transistors, 63 transistors, 64 diodes, 71 transistors, 72 diodes, 81 transistors, 82 diodes.

Claims (17)

[Claims] At least two power conversion means for converting DC power into AC power and supplying the AC power to a load, and connecting these electrode conversion means in series between a positive electrode of the DC power supply and a negative electrode of the DC power supply or in parallel with the DC power supply And a power combining means for combining the outputs of the plurality of power conversion means connected in series or in parallel by the series / parallel connection switching means and supplying the combined output to a load. AC power supply. 2. The serial / parallel connection switching means, wherein one DC input terminal is connected to a DC power supply positive electrode, and the other DC input terminal and one DC input terminal of the first AC power conversion means are connected to a DC power supply negative electrode. First opening / closing means that is openably and closably connected between the other DC input terminal of the second AC power converting means, and the other DC input terminal of the first AC power converting means and a DC power supply negative electrode A second opening / closing means connected to be openable and closable therebetween; and a third opening / closing means for opening / closing the other DC input terminal of the second AC power conversion means to a DC power supply positive electrode. The AC power supply device according to claim 1. 3. The series-parallel connection switching means, wherein one DC input terminal is connected to the DC power supply positive electrode, and the other DC input terminal and one DC input terminal of the first AC power conversion means are connected to the DC power supply negative electrode. First opening / closing means that is openably and closably connected between the other DC input terminal of the second AC power converting means, and the other DC input terminal of the first AC power converting means and a DC power supply negative electrode 2. A second opening / closing means connected between the second power conversion means and an open / closed connection means, and a connection means for connecting the other DC input terminal of the second power conversion means to the positive electrode of the DC power supply. 3. AC power supply. 4. The AC power supply according to claim 3, wherein the connection means is a diode having a cathode connected to the positive electrode of the DC power supply and an anode connected to the other DC input terminal of the second power conversion means. Power supply. 5. A method in which a plurality of three-phase windings are wound around a stator while being electrically insulated, and AC power generated by each AC power generator is input to each of the three-phase windings and synthesized. AC motor characterized by the following. 6. The AC motor according to claim 5, wherein each of the three-phase windings is electrically insulated and wound around the stator in the same phase. 7. Each of the AC power generators includes first and second PWs.
M inverters, and a carrier for generating a PWM signal output to each of the first and second PWM inverters is
7. The AC motor according to claim 5, wherein a phase of a carrier wave with respect to the second PWM inverter is shifted by π with respect to a phase of a carrier wave with respect to the first PWM inverter. 8. The armature according to claim 6, wherein the first three-phase winding and the second three-phase winding are electrically insulated and wound around the armature with a phase shift of π / 6. AC motor. 9. A first three-phase winding wound around an armature in a Y-connection, and the first three-phase winding is wound with an electrical angle of π / 6 phase shifted from the first three-phase winding. The three-phase winding 2 is connected in a △ connection,
The AC motor according to claim 8, wherein the first and second three-phase windings are connected in parallel. 10. An AC power is supplied to a first three-phase winding from a first AC power generator, and is supplied to a second three-phase winding by the first AC power generator. The AC motor according to claim 9, wherein the AC motor is driven by supplying AC power having an electrical angle π / 6 phase shifted from that of the AC power from a second AC power generator. 11. The ratio of the number of turns of the Y-connected first three-phase winding to the number of turns of the △ -connected second three-phase winding is approximately 1:
The AC motor according to claim 9 or 10, wherein $ 3. 12. A first three-phase winding and three-phase winding wound around a stator and Y-connected, and the first three-phase winding are wound with an electrical angle of π / 6 phase shifted and are △ -connected. The second three-phase winding is connected in parallel, and the first three-phase winding is shifted in phase by an electrical angle of π / 12 from the third three-phase winding and Y-connected to the third three-phase winding. 6. The AC motor according to claim 5, wherein a fourth three-phase winding wound and shifted in phase by an electrical angle of π / 6 from the third three-phase winding is connected in parallel. 13. The first and second three-phase windings connected in parallel are supplied with AC power from a first AC power generator, and the third and fourth three-phase windings connected in parallel are provided. The AC power supplied from the first AC power generator and having an electrical angle π / 12 phase shifted from the AC power supplied from the first AC power generator is supplied from the second AC power generator. AC motor. 14. When the first opening / closing means is in the open state, the second
4. The AC power supply device according to claim 2, wherein the switching operation of the third switching unit is repeated to change the DC input voltages of the first power converter and the second power converter. 5. 15. An opening / closing operation of the first opening / closing means when the second and third opening / closing means are in an open state;
4. The method according to claim 2, wherein when the first switching means is in the open state, the switching operation of the second and third switching means is repeated to change the DC input voltage of the first and second power converters. An AC power supply as described. 16. When the voltage command to the first and second power conversion means exceeds a predetermined value, the first and second power conversion means are driven in parallel, and the voltage command is equal to or less than a predetermined value. The switching signal output means for outputting a switching signal to the first to third opening / closing means so as to drive the first and second power conversion means in series, and the voltage command becomes lower than a predetermined value. 15. A voltage command output means for outputting a voltage command to said first and second power converters to a value twice as large as an original voltage command when said first and second power converters are output. The AC power supply device according to any one of the above. 17. When at least the first and second power converters are connected in series or in parallel, a drive unit is provided for fixing the modulation factor and performing PWM drive on the first and second power converters. 15. The method according to claim 14,
The alternating-current power supply device according to any one of Claims 15 to 15.