JP7088860B2 - AC power converter - Google Patents

Description

The present invention relates to an AC power converter that converts single-phase AC to three-phase AC.

It is easy to extract single-phase alternating current from three-phase alternating current. On the other hand, on the contrary, in order to generate a three-phase alternating current from a single-phase alternating current, generally, after rectifying the single-phase alternating current to direct current by the first converter (converter), the direct current is converted to the second converter. A method of converting to three-phase alternating current with (inverter) is used (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-21398

However, in order to generate a three-phase alternating current from a single-phase alternating current, many devices must be intervened.

For example, the AC power converter described in Patent Document 1 requires a Scott transformer, a converter, and an inverter. That is, as shown in FIG. 8, the first single-phase AC terminal electrically connected to the single-phase power supply 1 and the second single-phase AC terminal connected to the inverter 13 described later and the three-phase AC are output. A single-phase power source 1 is electrically connected to the first single-phase AC terminal of the Scott transformer 11 in parallel with the Scott transformer 11 having a three-phase AC terminal for the single-phase power supply 1. It is configured to include a converter 12 that converts AC to DC power, and an inverter 13 that converts DC power from the converter 12 into single-phase AC supplied to the second single-phase AC terminal of the Scott transformer 11. ing.

However, such a configuration not only becomes large in size and cost, but also has a problem that the conversion efficiency deteriorates.

The present invention was created in view of such circumstances, and is a simple AC power conversion device that converts single-phase AC to three-phase AC without using a transformer and using only one three-phase inverter. The purpose of the configuration is to enable high-efficiency conversion of single-phase alternating current to three-phase alternating current.

The present invention solves the above problems by taking the following measures.

The AC power converter according to the present invention is
A three-phase inverter is placed between the single-phase AC system on the input side and the three-phase AC system on the output side.
The three-phase inverter is configured by connecting the first to third switching arms and a DC side capacitor in parallel.
Two of the three three-phase side bus lines of the three-phase AC system are individually directly connected to the first and second single-phase side bus lines of the single-phase AC system, respectively. It is composed of the second three-phase generatrix,
The remaining one of the three three-phase generatrix is configured as a non-directly connected third three-phase generatrix that is not directly connected to the two single-phase generatrix.
The first single-phase side bus and the directly connected first three-phase bus are connected to the AC input / output terminal of the first switching arm.
The second single-phase side bus and the directly connected second three-phase side bus are connected to the AC input / output terminal of the second switching arm.
The non-directly connected third three-phase side bus is connected to the AC input / output terminal of the third switching arm.
The control unit for switching control for the first to third switching arms performs current control for the first and second switching arms and voltage control for the third switching arm. It is a feature.

The AC power conversion device of the present invention having the above configuration has several preferred embodiments as follows. In order to facilitate understanding, the numerical relations are described together with the reference numerals used in the examples described later. It should be noted that the present invention shall not be construed in a limited manner with this reference numeral.

(1) The control unit includes a phase detection unit, a voltage control calculation unit, a current control calculation unit, and a switching control signal generation unit.
The phase detection unit has a function of detecting the phase (θ ₁₂ ) of the line voltage (V ₁₂ ) between the first single-phase side bus and the second single-phase bus, and the voltage control. The arithmetic unit has a function of obtaining a command vector (V _α ) for the voltage of the non-directly connected third three-phase bus.
The current control calculation unit has a function of obtaining a command vector (V _β ) for a line voltage (V ₁₂ ) between the first and second three-phase side buses directly connected.
The switching control signal generation unit includes a command vector (V _α ) for the voltage of the third three-phase side bus and a command vector (V _β ) for the line voltage between the first and second three-phase bus. Based on the above, the output voltage vectors (V _invV , V _invW , V _invU ) of each of the first, second, and third three-phase side bus wires have a predetermined magnitude and phase. There is an aspect that it has a function of generating and outputting a switching control signal for the third switching arm.

(2) Further, the phase detection unit detects the phase (θ 12) of the line voltage (V ₁₂ ) between the first single-phase side bus and the second single-phase bus, and also detects the phase (θ ₁₂ ). It has a function to obtain the phase (θ ₃ ) of the voltage (V ₃ ) of the non-directly connected third three-phase side bus by calculation from the phase (θ ₁₂ ) of the line voltage (V ₁₂ ).
The voltage control calculation unit is the non-directly connected third by feedback control that minimizes the deviation between the detected voltage value (V ₃ ) of the non-directly connected third three-phase bus and the predetermined target voltage value as much as possible. The voltage peak command value (V _3ref ) for the three-phase side bus is obtained, and the phase (θ ₃ ) of this voltage peak command value (V _3ref ) and the voltage (V ₃ ) of the third non-directly connected third three-phase bus. Has a function of obtaining a command vector (V _α ) for the voltage of the non-directly connected third three-phase side bus from the above.
The current control calculation unit obtains a single-phase current peak command value (I _ref ) for the first single-phase side bus by feedback control that stabilizes the voltage (E) across the DC-side capacitor to a predetermined value. The single-phase current command vector (I Kref) is obtained from the phase (θ ₁₂ ) of the single-phase current peak command value (I _ref ) and the line voltage (V ₁₂ ), and the single-phase current command vector (I _Kref ) is obtained in the first or second single-phase side bus. Feedback control is performed to minimize the deviation between the single-phase current detection vector (I _K ) and the single-phase current command vector (I _Kref ), and the direct-current first and second three-phase side bus lines are connected to each other. There is an aspect that it has a function of obtaining a command vector (V _β ) for a line voltage (V ₁₂ ).

According to the above configuration of the present invention, the AC power conversion device for converting a single-phase AC to a three-phase AC has a simple configuration without using a transformer and using only one three-phase inverter. Can be converted to three-phase alternating current with high efficiency.

According to the present invention, it is possible to reduce the size, cost, and efficiency of an AC power conversion device that converts a single-phase AC to a three-phase AC.

A circuit diagram showing a configuration of an AC power conversion device according to an embodiment of the present invention. A circuit diagram showing an internal configuration of a filter such as LC of an AC power conversion device according to an embodiment of the present invention. A block diagram showing an internal configuration of a voltage control calculation unit of an AC power conversion device according to an embodiment of the present invention. A block diagram showing an internal configuration of a current control calculation unit of an AC power conversion device according to an embodiment of the present invention. A block diagram showing an internal configuration of a switching control signal generation unit of an AC power conversion device according to an embodiment of the present invention. A vector diagram for explaining the operation of the AC power conversion device in the embodiment of the present invention. A waveform diagram for explaining the operation of the AC power conversion device in the embodiment of the present invention. A circuit diagram showing the configuration of a conventional AC power converter

Hereinafter, the AC power conversion device of the present invention having the above configuration will be described in detail in detail at the level of specific examples.

FIG. 1 is a circuit diagram showing a configuration of an AC power conversion device according to an embodiment of the present invention. In FIG. 1, 30 is a single-phase AC system on the input side, 40 is a three-phase AC system on the output side, 50 is a three-phase inverter, and 60 is a PWM control control unit. 31 is the first single-phase side bus in the single-phase AC system 30, 32 is the second single-phase side bus, 41 is the first three-phase bus directly connected in the three-phase AC system 40, and 42 is the second directly connected bus. The three-phase side bus, 43, is a non-directly connected third three-phase side bus. Here, "directly connected" means that it is directly connected to the first single-phase side bus 31 or the second single-phase side bus 32 in the single-phase AC system 30, and is "non-directly connected". "" Means that there is no such direct connection.

51 is a first switching arm in the three-phase inverter 50, 52 is a second switching arm, 53 is a third switching arm, and 54 is a DC side capacitor. 61 is a phase detection unit in the control unit 60, 62 is a voltage control calculation unit, 63 is a current control calculation unit, and 64 is a switching control signal generation unit.

The three-phase inverter 50 connected between the single-phase AC system 30 on the input side and the three-phase AC system 40 on the output side has the first to third switching arms 51, 52, 53 and the DC side capacitor 54. It is configured by being connected in parallel. This is no different from a general three-phase inverter.

The three-phase AC system 40 has three three-phase side bus 41, 42, 43, two of which are the first and second single-phase side bus 31 of the single-phase AC system 30, respectively. , 32 are individually directly connected to the first and second three-phase side bus 41, 42 (V phase, W phase), and the remaining one is the two single-phase side bus 31, 32. It is composed of a non-directly connected third three-phase side bus 43 (U phase) that is not directly connected to.

In this embodiment, as an example, the correspondence between the three phases (U phase, V phase, W phase) and the first to third three-phase side bus 41, 42, 43 in the three-phase AC is taken as an example. The V phase corresponds to the directly connected first three-phase side bus 41, the W phase corresponds to the directly connected second three-phase side bus 42, and the U phase corresponds to the non-directly connected third three-phase side bus 43. I will let you.

Regarding the configuration of the three-phase inverter 50, in the first switching arm 51, the high-side switching element Q1a and the low-side switching element Q1b are connected in series via the AC input / output terminal N1, and the second switching arm 52 is high. The side switching element Q2a and the low side switching element Q2b are connected in series via the AC input / output terminal N2, and the third switching arm 53 has the high side switching element Q3a and the low side switching element Q3b AC input / output. The first to third switching arms 51, 52, and 53 are connected in series via the terminal N3, and the first to third switching arms 51, 52, and 53 are connected in parallel to each other, and the DC side capacitor 54 is also connected in parallel.

Regarding the relationship between the single-phase AC system 30 and the three-phase inverter 50, the first single-phase side bus 31 is connected to the AC input / output terminal N1 of the first switching arm 51, and the second single-phase side bus 32 is the second. It is connected to the AC input / output terminal N2 of the switching arm 52 of.

Regarding the relationship between the three-phase AC system 40 and the three-phase inverter 50, the first three-phase side bus 41 (V phase) directly connected to the first single-phase side bus 31 is the AC input / output terminal N1 of the first switching arm 51. The second three-phase side bus 42 (W phase) connected to the second single-phase side bus 32 and directly connected to the second single-phase side bus 32 is connected to the AC input / output terminal N2 of the second switching arm 52, and is connected to the first single-phase side. The third three-phase side bus 43 (U phase), which is not directly connected to the bus 31 and the second single-phase side bus 32, is connected to the AC input / output terminal N3 of the third switching arm 53. It is connected.

A filter 44 such as LC is connected between the first to third three-phase side bus 41 (V phase), 42 (W phase), and 43 (U phase) in the immediate vicinity of the AC input / output terminals N1, N2, and N3. Has been done. The filter 44 is for forming a voltage waveform of three-phase alternating current generated by the switching operation of the three-phase inverter 50 into a highly accurate sine wave.

An example of a detailed circuit configuration of the filter 44 is shown in FIG. The coils L _1a and L _1b are inserted into the first three-phase bus 41, the coils L 2a and L 2b are inserted into the second three-phase bus 42, and the coils L _2a and L _2b are inserted into the third three-phase bus 43. The coils L _3a and L _3b are inserted. Further, a capacitor C ₁₂ is connected between the first and second three-phase side bus lines 41 and 42, and a capacitor C ₂₃ is connected between the second and third three-phase side bus lines 42 and 43. A capacitor C ₃₁ is connected between the first three-phase side bus 43 and 41.

As described above, in order to convert single-phase alternating current to three-phase alternating current, a method is adopted in which only one three-phase inverter 50 is used as a converter and no transformer is used. Such a method is realized. The control unit 60 for PWM control for the first to third switching arms 51, 52, 53 in the three-phase inverter 50 is configured as follows.

That is, the control unit 60 includes a phase detection unit 61, a voltage control calculation unit 62, a current control calculation unit 63, and a switching control signal generation unit 64, and each of these components is configured as follows. ing.

The phase detection unit 61 has a first single-phase side bus 31 and a second single-phase side as the detection phase processed by the phase comparator (PFD) of the previous stage portion in the PLL (Phase Locked Loop) circuit. The phase θ ₁₂ (θ _VW ) of the line voltage V ₁₂ (V _VW ) between the bus and the bus 32 is detected, and the phase θ ₁₂ (θ _VW ) of this line voltage V ₁₂ (V _VW ) is not calculated. It has a function of obtaining the phase θ ₃ (θ _U ) of the voltage V ₃ (V _U ) of the directly connected third three-phase side bus 43 (U phase).

The phase detection unit 61 is, for example,
θ ₃ = θ ₁₂ + 90 ° That is, θ _U = θ _VW + 90 °
Line voltage V ₁₂ (V phase) between the directly connected first three-phase side bus 41 (V phase) and the directly connected second three-phase side bus 42 (W phase) (V phase W phase) according to the calculation of. It has a function to obtain the phase θ ₃ (θ _U ) of the voltage V ₃ (V _U ) of the non-directly connected third three-phase side bus 43 (U phase) from the phase θ ₁₂ (θ _VW ) of _VW ). .. The phase θ ₁₂ (θ _VW ) is sent to the current control calculation unit 63, and the phase θ ₃ (θ _U ) is sent to the voltage control calculation unit 62.

In the above phase calculation, in this embodiment, the clockwise direction is the positive direction of the phase.

The voltage control calculation unit 62 is non-directly connected to the feedback control unit 62a that maintains the detected voltage value V ₃ (V _U ) at a predetermined size for the non-directly connected third three-phase side bus 43 (U phase). It is provided with a command vector calculation unit 62b for obtaining a command vector V _α (referred to as a first command vector V _α ) for a voltage V ₃ (V _U ) of the third three-phase side bus 43 (U phase). ..

As shown in detail in FIG. 3, the feedback control unit 62a as a component performs an effective value calculation for the detected voltage value V ₃ (V _U ) of the non-directly connected third three-phase side bus 43 (U phase). , The deviation between this and the predetermined target voltage value is taken, feedback control is performed so that the deviation is minimized as much as possible, and the information obtained as a result is used as a non-directly connected third three-phase side bus 43 (U phase). ) As a voltage peak command value V _3ref (V _Uref ), which is sent to the command vector calculation unit 62b in the subsequent stage.

The command vector calculation unit 62b as a component receives the phase θ ₃ (θ _U ) of the voltage V ₃ (V _U ) of the non-directly connected third three-phase side bus 43 (U phase) from the phase detection unit 61. , The cosine function operation (cos operation) is applied to this to generate the cosine function cos θ ₃ (cos θ _U ), and the voltage peak command value V _3ref (V _Uref ) is received from the feedback control unit 62a in the previous stage. Multiplying this by the above-mentioned cosine function cos θ ₃ (cos θ _U ), the command vector V _α (first command) for the voltage V ₃ (V _U ) of the non-directly connected third three-phase side bus 43 (U phase). Vector) That is
V _α = V _3ref・ cosθ ₃ That is, V _α = V Uref ・_{cosθ U}
It is configured to have a function to obtain. The first command vector V _α is sent to the switching control signal generation unit 64.

The current control calculation unit 63 includes a feedback control unit 63a in the previous stage for obtaining the single-phase current peak command value I _ref of the first single-phase side bus 31, and a single-phase current for obtaining the single-phase current command vector I _{K ref} . The command vector for the line voltage V ₁₂ (V _VW ) between the command vector calculation unit 63b and the directly connected first three-phase side bus 41 (V phase) and the second three-phase side bus 42 (W phase). It is provided with a feedback control unit 63c in the subsequent stage for obtaining V _β (referred to as a second command vector V _β ).

As shown in detail in FIG. 4, the feedback control unit 63a in the previous stage as the component takes a deviation between the voltage E across the DC side capacitor 54 in the three-phase inverter 50 and the predetermined DC voltage command value E _ref , and the deviation thereof is taken. Feedback control is performed so that the deviation is minimized as much as possible, and the information obtained as a result is set as the single-phase current peak command value I _ref .

The single-phase current command vector calculation unit 63b as a component is a line voltage V ₁₂ (V _VW ) between the phase detection unit 61 and the first single-phase side bus 31 and the second single-phase side bus 32. The phase _{θ 12} (θ _VW ) _of The command value I _ref is received, and this is multiplied by the above-mentioned cosine function cos θ ₁₂ (cos θ _VW ) to obtain the single-phase current command vector I _{K ref} .
I _Kref = I _ref · cosθ ₁₂ That is, I _Kref = I _ref · cosθ _VW
And send it to the feedback control unit 63c in the subsequent stage.

The feedback control unit 63c in the subsequent stage as the component has a single-phase current detection vector I _K on the first single-phase side bus 31 and a single-phase current command vector I _Kref received from the single-phase current command vector calculation unit 63b. The deviation is taken and feedback control is performed so that the deviation is minimized as much as possible. As a result, the first three-phase side bus 41 (V phase) and the second three-phase side bus 42 (W phase) that are directly connected are directly connected. It has a function of obtaining a command vector V _β (second command vector) for an interline voltage V ₁₂ (V _VW ). The second command vector V _β is
V _β = V ₁₂ · cos θ ₁₂ That is, V _β = V _VW · cos θ _VW
Will be. The second command vector V _β is sent to the switching control signal generation unit 64.

As a result of the calculation by the current control calculation unit 63, the line voltage between the first single-phase side bus 31 and the second single-phase side bus 32, which is the basis of the phase θ ₁₂ (θ _VW ). For V ₁₂ (V _VW ), the single-phase current detection vector I _K on the first single-phase side bus 31 (or the same for the second single-phase side bus 32) is set to the same phase, and the power factor is adjusted to 1. It will be. When the power factor is adjusted to 1, the phase of the line voltage vector between the single-phase bus and the phase of the single-phase current vector are kept in phase, and the ratio of the magnitudes of both vectors changes the phase. Regardless, it is always kept constant.

Therefore, the relative relationship between the phase of the first command vector V _α and the phase of the second command vector V _β is the voltage V ₃ (V _U ) of the non-directly connected third three-phase side bus 43 (U phase). ) Phase θ ₁₂ (θ _VW ) of the line voltage V ₁₂ (V _VW ) between the first and second three-phase side bus 41, 42 (between V phase and W phase) directly connected to the phase θ ₃ (θ _U ). Is equivalent to the relative relationship of.

The switching control signal generation unit 64 has the first, second, and third three-phase side bus 41, 42 based on the first command vector V _α and the second command vector V _β obtained above. , 43 It has a function of generating and outputting a switching control signal for the first to third switching arms 51, 52, 53 so that each output voltage vector has a predetermined magnitude and phase.

That is, the output voltage vector V _inv U from the AC input / output terminal N3 of the third switching arm 53 (U phase) in the three-phase inverter 50 is controlled so as to match the command vector V _α , and the first switching arm is also controlled. The output voltage vector V invV from the AC input / output terminal N1 of 51 (V phase) and the output voltage vector V _invW from the AC input / output terminal N2 of the second switching arm 52 (W phase) are the first command vectors V, respectively _. Control is performed from _α and the second command vector V _β so as to follow the following calculation (FIG. 5).

V _invU = V _α
V _invV =-(1/2) V _α + (√3 / 2) V _β
V _invW =-(1/2) V _α- (√3 / 2) V _β
The switching control signal generation unit 64 has high-side and low-side switching elements Q1a, Q1b, Q2a in the first to third switching arms 51, 52, 53 so that these three vector operations are simultaneously established. It has a function to generate and output PWM control signals for Q2b, Q3a, and Q3b. In the above formula, the notation of "√3" means "square root 3".

The first command vector V _α is
V _α = V _3ref・ cosθ ₃ That is, V _α = V Uref ・_{cosθ U}
It has become. The second command vector V _β is
V _β = V ₁₂ · cos θ ₁₂ That is, V _β = V _VW · cos θ _VW
It has become. The relationship between phase θ ₃ (θ _U ) and phase θ ₁₂ (θ _VW ) is as described above.
θ ₃ = θ ₁₂ + 90 ° That is, θ _U = θ _VW + 90 °
It has become.

Fig. 6 (a) shows the relative relationship between the first command vector V _α and the second command vector V _β using a vector diagram (complex number display). The horizontal axis is the real axis and the vertical axis is the imaginary axis. The phase θ _β of the second command vector V _β is shifted in the negative direction (counterclockwise direction) from the phase θ _α of the first command vector V _α . The shift phase is 90 °.

When the first command vector V _α is normalized so as to be along the real axis, it becomes as shown in FIG. 6 (b), and the second command vector V _β is in a state along the imaginary axis (upper side).

In this state, the above equation,
V _invV =-(1/2) V _α + (√3 / 2) V _β
V _invW =-(1/2) V _α- (√3 / 2) V _β
The output voltage vector V invV from the first switching arm 51 (V phase) and the output voltage vector V _invW from the second switching arm 52 (W phase) according to the _above are drawn as shown in FIG. 6 (c). The output voltage vector from the third switching arm 53 (U phase) is V _invU = V _α .

Both the V-phase output voltage vector V _invV and the W-phase output voltage vector V _invW have the same magnitude as the U-phase output voltage vector V _invU . The phase θ _invV of the V-phase output voltage vector V _invV has a delay of 120 ° from the phase θ _invU of the U-phase output voltage vector V _invU , and the phase θ _invW of the W-phase output voltage vector V _invW is the V-phase output. It has a lag of 120 ° from the phase θ _invV of the voltage vector V _invV (clockwise is the positive phase).

The vector of the line voltage V _invVW connecting the vector tip of the W phase output voltage vector V _invW to the V phase output voltage vector V _invV vector tip is parallel to the second command vector V _β along the imaginary axis, and U The relationship is perpendicular to the phase output voltage vector V _invU . The magnitude of the vector of the line voltage V _invVW is √3 times the second command vector V _β .

The simulation results of the experiment of the method of this embodiment are shown in the waveform diagram of FIG. Waveform # 1 is a single-phase voltage (V _VW ) sine wave waveform, waveform # 2 is a single-phase current (I _K ) sine wave waveform, and waveform # 3 is a U-phase output voltage (V _invU ) sine wave waveform. Waveform # 4 is a sine wave waveform of V phase output voltage (V _invV ), and waveform # 5 is a sine wave waveform of W phase output voltage (V _invW ).

The sinusoidal waveform # 1 of the single-phase voltage ( _VVW ) and the sinusoidal waveform # 2 of the single-phase current ( _IK ) are in phase with a power factor of 1. The U-phase output voltage (V _invU ) sinusoidal waveform # 3, the V-phase output voltage (V _invV ) sinusoidal waveform # 4, and the W-phase output voltage (V _invW ) sinusoidal waveform # 5 are amplitudes of each other. Are equal and with a phase difference of 120 ° each.

As described above, according to this embodiment, it is possible to convert a single-phase alternating current into a three-phase alternating current with high efficiency by a simple configuration in which only one three-phase inverter is required and no transformer is used. , It is possible to realize miniaturization, cost reduction and high efficiency of the AC power conversion device.

INDUSTRIAL APPLICABILITY The present invention is useful as a technique for reducing the size, cost, and efficiency of an AC power conversion device that converts a single-phase AC to a three-phase AC.

30 Single-phase AC system 31 First single-phase side bus 32 Second single-phase side bus 40 Three-phase AC system 41 Directly connected first three-phase side bus (V phase)
42 Directly connected second three-phase generatrix <W phase>
43 Non-directly connected third three-phase generatrix (U phase)
50 Three-phase inverter 51 First switching arm 52 Second switching arm 53 Third switching arm 54 DC side capacitor 60 Control unit 61 Phase detection unit 62 Voltage control calculation unit 63 Current control calculation unit 64 Switching control signal generation unit N1 , N2, N3 AC input / output terminal

Claims (3)

A three-phase inverter is placed between the single-phase AC system on the input side and the three-phase AC system on the output side.
The three-phase inverter is configured by connecting the first to third switching arms and a DC side capacitor in parallel.
Two of the three three-phase side bus lines of the three-phase AC system are individually directly connected to the first and second single-phase side bus lines of the single-phase AC system, respectively. It is composed of the second three-phase generatrix,
The remaining one of the three three-phase generatrix is configured as a non-directly connected third three-phase generatrix that is not directly connected to the two single-phase generatrix.
The first single-phase side bus and the directly connected first three-phase bus are connected to the AC input / output terminal of the first switching arm.
The second single-phase side bus and the directly connected second three-phase side bus are connected to the AC input / output terminal of the second switching arm.
The non-directly connected third three-phase side bus is connected to the AC input / output terminal of the third switching arm.
The control unit for switching control for the first to third switching arms performs current control for the first and second switching arms and voltage control for the third switching arm. Characterized AC power conversion device. The control unit includes a phase detection unit, a voltage control calculation unit, a current control calculation unit, and a switching control signal generation unit.
The phase detection unit has a function of detecting the phase of the line voltage between the first single-phase side bus and the second single-phase side bus.
The voltage control calculation unit has a function of obtaining a command vector for the voltage of the non-directly connected third three-phase side bus.
The current control calculation unit has a function of obtaining a command vector for a line voltage between the first and second three-phase side buses directly connected.
The switching control signal generation unit is based on the command vector for the voltage of the third three-phase side bus and the command vector for the line voltage between the first and second three-phase bus. It has a function to generate and output a switching control signal for the first to third switching arms so that the output voltage vectors of each of the second and third three-phase side bus wires have a predetermined magnitude and phase. The AC power conversion device according to claim 1. The phase detection unit calculates the phase of the voltage of the non-directly connected third three-phase bus by calculating from the phase of the line voltage between the first single-phase bus and the second single-phase bus. Seeking,
The voltage control calculation unit is the non-directly connected third three-phase side by feedback control that minimizes the deviation between the detected voltage value of the non-directly connected third three-phase side bus and the predetermined target voltage value as much as possible. A function to obtain the voltage peak command value for the bus, and to obtain the command vector for the voltage of the non-directly connected third three-phase side bus from the phase of this voltage peak command value and the voltage of the non-directly connected third three-phase side bus. Have,
The current control calculation unit obtains a single-phase current peak command value for the first single-phase side bus by feedback control that stabilizes the voltage across the DC-side capacitor to a predetermined value, and uses this single-phase current peak command value. Feedback control that obtains the single-phase current command vector from the phase of the line voltage and minimizes the deviation between the single-phase current detection vector and the single-phase current command vector in the first or second single-phase side bus. 2. The AC power conversion device according to claim 2, which has a function of obtaining a command vector for a line voltage between the first and second three-phase side bus wires directly connected to each other.

Images