JP3481885B2 - Inverter device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device for driving an AC electric motor provided with a plurality of single-phase windings as a multi-phase winding for generating a rotating magnetic field, and more particularly to an AC electric motor driven by an armature reaction. The present invention relates to an inverter device that suppresses torque ripple by keeping the instantaneous electric power at a constant value even when the induced voltage waveform of the single-phase winding deviates from a square wave.

[0002]

2. Description of the Related Art Conventionally, pulse width modulation (hereinafter referred to as PWM
Generally, a PWM inverter device that supplies a three-phase alternating current to drive an alternating-current motor by control (hereinafter referred to as "control") has been widely used.

FIG. 11 is a block diagram showing a configuration example of a conventional PWM inverter device of this type.

In FIG. 11, a PWM inverter 41 for driving an AC electric motor 40 having a plurality of single-phase windings as a multi-phase winding for generating a rotating magnetic field has a three-phase winding based on a speed reference.
The motor control unit 42 that outputs the phase current reference Ir and the three-phase current reference Ir and the three-phase current detection value I detected by the current detector 46 are respectively compared, and the three-phase current control signal Sc is compared. PWM for generating the PWM signal Sp based on the current control unit 43 that outputs
The AC motor 4 includes a control unit 44 and an inverter unit 45 that converts a direct current into a three-phase alternating current based on the PWM signal Sp and supplies an alternating current corresponding to the three-phase current reference Ir.
0 is driven.

Generally, a sine wave is used as an alternating current supplied by the PWM inverter device in order to generate a smooth rotating magnetic field.

However, in the case where the induced voltage waveform of the single-phase winding is a square wave, such as a permanent magnet electric motor, when the induced voltage of the electric motor and the DC power supply voltage approach each other, the inverter device Since the peak value of the output AC voltage is limited to the value of the DC power supply voltage, the voltage for flowing the peak current may be insufficient and the capacity may be insufficient.

Therefore, there has been proposed a method of increasing the utilization factor of the DC power supply voltage by using a square wave or the like instead of using the sine wave as the AC waveform to secure the output capacity.

[0008]

However, when an alternating current is applied to the permanent magnet motor as in the method described above, the induced voltage in the single-phase winding deviates from the square wave due to the influence of the armature reaction. The purpose of making the alternating current a square wave is that the induced voltage of the single-phase winding is a square wave.
It tries to make the instantaneous power, which is the product of current and voltage, constant, but if the induced voltage in the single-phase winding does not become a square wave due to the effect of armature reaction, the desired motor output can be obtained. There is a possibility that torque ripple will occur due to fluctuations in the instantaneous power of the inverter device.

The object of the present invention is to suppress the torque ripple by keeping the instantaneous electric power at a constant value even when the induced voltage waveform of the single-phase winding of the AC motor deviates from the square wave due to the influence of the armature reaction. It is to provide an inverter device capable of performing the above.

[0010]

In order to achieve the above-mentioned object, an inverter device for driving an AC motor having a plurality of single-phase windings as a multi-phase winding for generating a rotating magnetic field is provided. According to the present invention, a plurality of inverters that perform current control based on a current reference and supply alternating current to a plurality of single-phase windings of an AC motor by pulse width modulation (PWM) control to generate a rotating magnetic field and drive the AC motor. And a current command determination unit that is provided corresponding to each inverter and that individually gives a current command to the corresponding inverter, and a voltage detection unit that detects the voltage of the single-phase winding of the AC motor. Based on the current reference and the voltage reference common to each inverter and the detected voltage from the voltage detection means, the means keeps the instantaneous power of the corresponding inverter constant.
As described above, the current command calculating means calculates a current command.

Therefore, in the inverter device of the first aspect of the invention, the corresponding inverter is based on the current reference and voltage reference (inverter output reference) common to each inverter and the detected voltage of the single-phase winding of the AC motor. By generating the current command of 1 so that the instantaneous power is kept constant, the instantaneous power of each inverter is kept constant, and the combined power of the plurality of single-phase windings can be made to include no ripple.

According to the second aspect of the invention, the current control is performed based on the current reference, and the alternating current is supplied to the plurality of single-phase windings of the AC motor by the pulse width modulation (PWM) control to generate the rotating magnetic field. And a plurality of inverters for driving the AC motor, a current command determining unit that is provided corresponding to each inverter and that individually gives a current command to the corresponding inverter, and a position detecting unit that detects the rotor position of the AC motor. The current command determining means pre-stores the generated voltage waveform of the single-phase winding of the AC motor according to each load current value, and the current reference common to each inverter and the detection position from the position detecting means. Based on the voltage waveform storage means for generating a corresponding voltage waveform, the current reference common to each inverter and the voltage reference, and the voltage waveform from the voltage waveform storage means. One of the instantaneous power of the corresponding inverter
And a current command calculation means for calculating a current command so as to keep it constant .

Therefore, in the inverter device of the second aspect of the present invention, the current reference and voltage reference (inverter output reference) common to each inverter, the rotor detection position of the AC motor, and the voltage waveform storage means are stored. By generating a current command based on the voltage waveform so that the instantaneous power of the corresponding inverter will be constant, the instantaneous power of each inverter will be kept constant, and the combined power of multiple single-phase windings will also have ripples. It may not be included.

Further, in the third aspect of the invention, in the inverter device of the second aspect of the invention, voltage detection means for detecting the voltage of the single-phase winding of the AC motor is added to detect the voltage during operation of the AC motor. Learning means for updating the voltage waveform pattern of the voltage waveform storage means based on the detected voltage from the means is provided.

Therefore, in the inverter device according to the third aspect of the present invention, in addition to exhibiting the same effect as that of the second aspect of the invention, based on the actual detected voltage of the single-phase winding of the AC motor during operation. By updating the voltage waveform pattern of the voltage waveform storage means by the above, it is possible to prevent the characteristics from being deteriorated even if the electric motor system changes over time.

On the other hand, in the invention of claim 4, the current control is performed based on the current reference, and the alternating current is supplied to the plurality of single-phase windings of the AC motor by the pulse width modulation (PWM) control to generate the rotating magnetic field. And a plurality of inverters for driving the AC motor, a current command determining unit that is provided corresponding to each inverter and that individually gives a current command to the corresponding inverter, and a position detecting unit that detects the rotor position of the AC motor. The current command determining means pre-stores the generated voltage waveform of the single-phase winding of the AC motor according to each load current value, and the current reference common to each inverter and the detection position from the position detecting means. Voltage waveform storage means for generating a corresponding voltage waveform, and a power reference from a current reference and a voltage reference common to each inverter, and the power reference and position. Based on the detected position from the output means, a power command calculation means for calculating the power command of the corresponding inverter whose rise and fall are linear, and the power command from the power command calculation means and the voltage waveform storage means. based of the voltage waveform, the instantaneous collector and another inverter
It is composed of a current command calculation means for calculating a current command so as to cancel out force fluctuations .

Therefore, in the inverter device of the fourth aspect of the present invention, in addition to exhibiting the same operation as that of the second aspect of the invention, a common current reference and voltage reference (inverter output reference) and an alternating current are shared by each inverter. Based on the detected position of the rotor of the electric motor and the voltage waveform stored in the voltage waveform storage means, the rise and fall of the instantaneous power of the corresponding inverter are linearized to cancel the fluctuation of the instantaneous power with other inverters. By generating the current command so as to match, the ripple of the combined power can be suppressed even when the rise of the induced voltage in the single-phase winding of the AC motor has a slope.

In the invention of claim 5, the current control is performed based on the current reference, and the alternating current is supplied to the plurality of single-phase windings of the AC motor by the pulse width modulation (PWM) control to generate the rotating magnetic field. And a plurality of inverters for driving the AC motor, a current command determining unit that is provided corresponding to each inverter and that individually gives a current command to the corresponding inverter, and a position detecting unit that detects the rotor position of the AC motor. The current command determination means stores in advance a generated voltage waveform of the single-phase winding of the AC motor according to each load current value, and a current reference common to each inverter and a detection position from the position detection means. Based on the voltage waveform storage means for generating a corresponding voltage waveform, and a power reference from a current reference and a voltage reference common to each inverter, and the power reference Power command calculation means for calculating the power command of the corresponding inverter in which rising and falling are made sinusoidal based on the detected position from the position detection means, and the power command and voltage waveform storage from the power command calculation means Based on the voltage waveform from the means, the current command calculation means calculates a current command so as to cancel out the fluctuations in the instantaneous power of the corresponding inverters.

Therefore, in the inverter device of the fifth aspect of the present invention, in addition to the same effect as that of the second aspect of the invention, a common current reference and voltage reference (inverter output reference) and an alternating current are shared by each inverter. Based on the detected position of the rotor of the electric motor and the voltage waveform stored in the voltage waveform storage means, the rise and fall of the instantaneous power of the corresponding inverter are made sinusoidal to change the variation of the instantaneous power with other inverters. By generating the current command so as to cancel each other, the ripple of the combined power can be suppressed even when the rise of the induced voltage in the single-phase winding of the AC motor has a slope.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing a configuration example of an inverter device according to the present embodiment.

In FIG. 1, an AC motor 1 is provided with a plurality of independent (eight in the figure) single-phase windings as multi-phase windings that generate a rotating magnetic field.

On the other hand, the inverter device for driving the AC motor 1 includes a position detector 2, a plurality (8 in the figure) of inverters 3-1 to 3-8, and a plurality (8 in the figure) of current command determination. The units 4-1 to 4-8 and the motor control unit 5 are included.

The position detector 2 detects the rotor position θ of the AC motor 1.

The inverters 3-1 to 3-8 perform current control based on a current reference, and supply a single-phase alternating current to a plurality of single-phase windings of the AC motor 1 by PWM control to generate a rotating magnetic field. Generate and drive the AC motor 1.

The current command determining units 4-1 to 4-8 are provided corresponding to the respective inverters 3-1 to 3-8 and detect the current reference Ir common to the respective inverters 3-1 to 3-8. Based on the voltage v1, corresponding inverters 3-1 to 3-1
Give a current command individually to -8.

The electric motor control unit 5 calculates (differentiates) the electric motor speed based on the detected position θ from the position detector 2 and controls so that the electric motor speed follows the speed reference. A current reference Ir common to 3-8 is generated.

FIG. 2 shows the current command determining units 4-1 to 4-.
8 and an inverter 3-1 to 3-8 are block diagrams showing internal configuration examples.

Since the current command determination units 4-1 to 4-8 and the inverters 3-1 to 3-8 all have the same structure, the current command determination unit 4-1 and the inverter 3-1 are used here. Only the configuration of will be illustrated and described.

In FIG. 2, the inverter 3-1 includes a current control unit 21, a PWM control unit 22, and an inverter unit 23.
And a current detector 24 and a voltage detector 25.

The current control unit 21 includes a current command determination unit 4-1.
Single-phase current command Ir1 given from the current detector 2
The current control signal is output by comparing the single-phase detected current value i1 of the inverter 3-1 detected by No.

The PWM control section 22 outputs a PWM signal for PWM based on the current control signal from the current control section 21.

The inverter section 23 converts direct current into alternating current based on the PWM signal from the PWM control section 22 and outputs a single-phase alternating current i1.

The current detector 24 detects a single-phase current of the inverter 3-1.

The voltage detector 25 detects the voltage of the single phase of the inverter 3-1 or the voltage of the single phase winding of the AC motor 1.

On the other hand, the current command determining section 4-1 comprises a reference voltage commanding section 31 and a current command computing section 32.

The reference voltage command section 31 outputs the voltage reference Vr.

The current command calculator 32 is provided for each inverter 3-.
The current reference Ir common to 1 to 3-8 and the reference voltage command unit 3
Based on the voltage reference Vr from 1 and the detected voltage v1 from the voltage detector 25, the corresponding current command Ir1 of the inverter 3-1 is calculated.

Next, the operation of the inverter device of the present embodiment having the above configuration will be described with reference to FIG.

In FIG. 1, a plurality of single-phase windings of the AC motor 1 are arranged at positions sequentially shifted so as to generate a rotating magnetic field forming a plurality of poles by an alternating magnetic field generated by each single-phase winding. All are independent (insulated) single-phase windings.

The inverters 3-1 to 3-8 individually perform PWM control independently of other inverters,
Single-phase alternating currents I1 to I8 respectively corresponding to the current references Ir1 to Ir8 are supplied to the respective single-phase windings of the AC motor 1 to generate a rotating magnetic field and rotate the rotor of the AC motor 1.

The electric motor control unit 5 calculates (differentiates) the electric motor speed based on the detected position θ from the position detector 2 and controls the electric motor speed so as to follow the speed reference. A current reference Ir common to 3-8 is generated.

On the other hand, in FIG. 3A, the AC motor 1
Is a no-load state, the induced voltage waveform of the single-phase winding becomes a square wave as shown by the dotted line. If the induced voltage waveform does not change even if a current is applied, the current command is shown in Fig. 3 (b). By making it a square wave as indicated by the dotted line, the instantaneous power determined by voltage x current has a constant value that does not include ripples.

However, when an electric current is actually applied, it deviates from the square wave as shown by the solid line in FIG. 3A due to the influence of the armature reaction.

At this time, when the current waveform is a square wave, the instantaneous power determined by voltage × current is as shown by the dotted line in FIG. 3 (c), and a plurality of single-phase windings (in the present embodiment, The combined power of 8) includes ripples as shown by the dotted line in FIG.

In this respect, in the present embodiment, the current command Ir1 of each of the inverters 3-1 to 3-8 is supplied to the current reference Ir and the no load in the current command calculation unit 32 of the current command determination unit 4-1. On the basis of the voltage reference Vr equal to the induced voltage at time and the actual detected voltage (induced voltage) v1, calculation is performed by the relational expression of Ir1 = Ir × Vr ÷ v1.

This is to change the current according to the induced voltage so that the instantaneous power determined by voltage × current is kept constant, and the current waveform is as shown by the solid line in FIG. 3 (b).

Thereby, each inverter 3-1 to 3-8
The instantaneous power of is kept constant, and the combined power of the multiple single-phase windings also does not contain ripples.

As described above, in the inverter device of the present embodiment, the current reference and voltage reference (inverter output reference) common to each inverter 3-1 to 3-8 and the detection of the single-phase winding of the AC motor 1 are detected. Since the current commands for the corresponding inverters 3-1 to 3-8 are generated based on the voltage, the instantaneous power of each inverter 3-1 to 3-8 is kept constant, and a plurality of single-phase The combined power of the winding can also be free of ripples.

(Second Embodiment) FIG. 4 is a block diagram showing a configuration example of an inverter device according to the present embodiment. The same elements as those in FIG. 1 are designated by the same reference numerals and their description is omitted. , Here, only different parts will be described.

That is, as shown in FIG. 4, the inverter device of the present embodiment has the position detector 2 in FIG.
The detected position θ from the current command determination units 4-1 to 4-8
It is also configured to input to.

The current command determination units 4-1 to 4-8 are provided corresponding to the respective inverters 3-1 to 3-8 and detect the common current reference Ir common to the respective inverters 3-1 to 3-8. Based on the voltage v1 and the detected position θ from the position detector 2, a current command is individually given to the corresponding inverters 3-1 to 3-8.

FIG. 5 shows the current command determining units 4-1 to 4-.
8 and inverters 3-1 to 3-8 are block diagrams showing an internal configuration example, the same elements as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. Only different portions will be described here.

Since the current command determining units 4-1 to 4-8 and the inverters 3-1 to 3-8 all have the same configuration, here, the current command determining unit 4-1 and the inverter 3-1. Only the configuration of will be illustrated and described.

In FIG. 5, the voltage detector 25 of the inverter 3-1 in FIG. 2 is omitted.

On the other hand, the current command determination unit 4-1 is composed of a reference voltage command unit 31, a current command calculation unit 32, and a voltage waveform storage unit 33.

The reference voltage command section 31 outputs the voltage reference Vr.

The voltage waveform storage unit 33 stores the generated voltage waveform of the single-phase winding of the AC motor 1 according to each load current value (in the present embodiment, the current command Ir1 and the rotor position θ of the AC motor 1). It is stored in advance and each inverter 3-
A corresponding voltage waveform v is generated based on the current reference Ir common to 1 to 3-8 and the detected position θ from the position detector 2.

The current command calculator 32 is provided for each inverter 3-.
The current reference Ir common to 1 to 3-8 and the reference voltage command unit 3
Based on the voltage reference Vr from 1 and the voltage waveform v from the voltage waveform storage unit 33, the corresponding current command Ir1 of the inverter 3-1 is calculated.

Next, the operation of the inverter device of the present embodiment configured as described above will be described.

The description of the operation of the same parts as those of the first embodiment will be omitted, and only different parts will be described here.

In FIG. 4, the induced voltage waveform of the single-phase winding of the AC motor 1 depends on the rotor position θ of the AC motor 1 and the current reference Ir.

Therefore, in the present embodiment, the two parameters of the current reference Ir and the detection position θ are used as parameters and v
= F (θ, Ir), the voltage waveform is stored in advance in the voltage waveform storage unit 33 of the current command determination unit 4-1.

In the voltage waveform storage unit 33, each inverter 3
The common current reference Ir and the detection position θ from the position detector 2 are input to −1 to 3-8, and the voltage waveform v stored in advance is output.

The current command calculation unit 32 uses the voltage waveform v (induced voltage) from the voltage waveform storage unit 33 to set the current command Ir1 of each inverter 3-1 to 3-8 so that the instantaneous power becomes constant. , Ir1 = Ir × Vr ÷ v.

This is to change the current in accordance with the induced voltage in order to make the instantaneous power determined by voltage × current constant, and the current waveform is as shown by the solid line in FIG. 3 (b).

As a result, also in this embodiment, the instantaneous power of each inverter 3-1 to 3-8 is kept constant,
The combined power of the multiple single-phase windings also does not include ripples.

As described above, in the inverter device of the present embodiment, the current reference and voltage reference (inverter output reference) common to each inverter 3-1 to 3-8 and the rotor detection position of the AC motor 1 are set. Based on the voltage waveform stored in the voltage waveform storage unit 33, the corresponding inverter 3
Since the current command is generated so that the instantaneous power of -1 to 3-8 is constant, each inverter 3-1 to 3-1
The instantaneous power of −8 is kept constant, and the combined power of the plurality of single-phase windings can also be free of ripples.

(Third Embodiment) FIG. 6 is a block diagram of the current command determining unit 4-1 in the inverter device according to the present embodiment.
4-8 and inverters 3-1 to 3-8 are block diagrams showing an internal configuration example, the same elements as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. Here, only different portions will be described. Describe.

Since the current command determining units 4-1 to 4-8 and the inverters 3-1 to 3-8 all have the same structure, the current command determining unit 4-1 and the inverter 3-1 are used here. Only the configuration of will be illustrated and described.

That is, in this embodiment, as shown in FIG. 6, the single-phase voltage of the inverter 3-1, that is, the voltage of the single-phase winding of the AC motor 1 is supplied to the inverter 3-1 in FIG. A voltage detector 25 for detecting is added, and the detected voltage v1 from the voltage detector 25 is supplied to the current command determination unit 4
It is configured to input to the voltage waveform storage unit 33 of -1.

The voltage waveform storage unit 33 stores the generated voltage waveform of the single-phase winding of the AC motor 1 according to each load current value (in the present embodiment, the current command Ir1 and the rotor position θ of the AC motor 1). It is stored in advance and each inverter 3-
A corresponding voltage waveform v is generated based on the current reference Ir common to 1 to 3-8 and the detected position θ from the position detector 2. Further, the voltage waveform storage unit 33 has a learning function of updating the voltage waveform pattern stored in advance based on the current command Ir1 and the rotor position θ of the AC motor 1.

Next, the operation of the inverter device of the present embodiment configured as described above will be described.

The description of the operation of the same parts as those of the second embodiment will be omitted, and only different parts will be described here.

In FIG. 6, the induced voltage waveform of the single-phase winding of the AC motor 1 depends on the rotor position θ of the AC motor 1 and the current reference Ir.

Therefore, in the present embodiment, the two parameters of the current reference Ir and the detection position θ are used as v
= F (θ, Ir), the voltage waveform is stored in advance in the voltage waveform storage unit 33 of the current command determination unit 4-1.

In the voltage waveform storage unit 33, each inverter 3
The common current reference Ir and the detection position θ from the position detector 2 are input to −1 to 3-8, and the voltage waveform v stored in advance is output.

On the other hand, in the voltage waveform storage section 33,
Based on the actual detected voltage value v1 (voltage of the single-phase winding of the AC motor 1) and the voltage waveform v stored in the voltage waveform storage unit 33, appropriate weighting factors w1 and w2 are shown in the following equation. Thus, the voltage waveform pattern f (θ, Ir) is updated.

F (θ, Ir) = w1 × v1 + w2 × v Thus, also in this embodiment, each inverter 3
The instantaneous electric powers of -1 to 3-8 are kept constant, and the combined electric power of the plurality of single-phase windings does not include ripples.

Further, based on the actual detected voltage value v1,
Since the voltage waveform that has been recorded in advance is updated,
The characteristics are not impaired even if the electric motor system changes over time.

As described above, in the inverter device of the present embodiment, the same effects as those of the second embodiment can be obtained, and in addition, the AC motor 1 during operation is
Since the voltage waveform pattern of the voltage waveform storage unit 33 is updated based on the actual detected voltage of the single-phase winding, the characteristics are not impaired even if the electric motor system changes over time. It becomes possible to do.

(Fourth Embodiment) FIG. 7 shows a current command determining unit 4-1 in the inverter device according to the present embodiment.
4-8 and inverters 3-1 to 3-8 are block diagrams showing an internal configuration example, the same elements as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. Here, only different portions will be described. Describe.

Since the current command determining units 4-1 to 4-8 and the inverters 3-1 to 3-8 all have the same structure, the current command determining unit 4-1 and the inverter 3-1 are used here. Only the configuration of will be illustrated and described.

That is, in the present embodiment, as shown in FIG. 7, the current command determining unit 4--1 of the current command determining unit 4-1 in FIG. 5 is omitted, and instead of this, the current command determining unit 4- is used. 1 has a configuration in which a multiplier 34, a power command unit 35, and a current command calculation unit 36 are added.

The multiplier 34 multiplies the voltage reference Vr from the reference voltage command section 31 by the current reference Ir common to the inverters 3-1 to 3-8, and outputs the power reference Pr.

The power command unit 35 calculates the power command Pr1 of the corresponding inverter 3-1 based on the power reference Pr from the multiplier 34 and the detected position θ from the position detector 2.

The current command calculation unit 36 linearly rises and falls based on the power command Pr1 from the power command unit 35 and the voltage waveform v from the voltage waveform storage unit 33, and the corresponding inverter 3- The current command Ir1 of 1 is calculated.

Next, the operation of the inverter device of the present embodiment having the above configuration will be described with reference to FIG.

The description of the operation of the same parts as those of the second embodiment will be omitted, and only the different parts will be described here.

In FIG. 7, when the polarity of the induced voltage waveform of the single-phase winding of the AC motor 1 is switched, it is ideally desired to be switched instantaneously, but in reality, there is some inclination.

At this time, the instantaneous power determined by voltage × current is
A valley is formed as shown by the dotted line in FIG. 8C, and the combined power of the plurality of single-phase windings of the AC motor 1 also contains ripples as shown by the dotted line in FIG. 8D.

Therefore, in the present embodiment, FIG.
As indicated by the solid line in (c), the rise and fall of the instantaneous power of the single-phase winding of the AC motor 1 is made to have a slope in advance to form a linear or trapezoidal wave, which cancels out with other single-phase windings. Try to fit.

Specifically, in the present embodiment, the power reference Pr is obtained by multiplying the voltage reference Vr from the reference voltage command unit 31 and the current reference Ir common to the respective inverters 3-1 to 3-8. Is output, and the power reference Pr1 and the rotor position θ of the AC motor 1 are used to output a power command Pr1 of the inverter having a trapezoidal waveform of rising and falling, and the power command Pr1 and the voltage from the voltage waveform storage unit 33. Based on the waveform v, the current command Ir of each inverter 3-1 to 3-8
1 is calculated by the relational expression Ir1 = Pr1 ÷ v.

As a result, even when the rise and fall of the induced voltage of the single-phase winding of the AC motor 1 has a slope,
The ripple of combined power can be suppressed.

As described above, in the inverter device of this embodiment, the same effects as those of the second embodiment can be obtained, and in addition, each inverter 3-1 to 3-8
Based on the common current reference and voltage reference (inverter output reference), the detected position of the rotor of the AC motor 1, and the voltage waveform stored in the voltage waveform storage unit 33, the rise of the instantaneous power of the corresponding inverter is determined. Since the current command is generated so as to cancel the fluctuation of the instantaneous power with other inverters by making the fall linear, even if the induced voltage of the single-phase winding of the AC motor has a rising slope, It is possible to suppress the ripple of the combined power.

(Fifth Embodiment) FIG. 9 is a block diagram of the current command determining unit 4-1 in the inverter device according to the present embodiment.
4-8 and inverters 3-1 to 3-8 are block diagrams showing an internal configuration example, the same elements as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. Describe.

Since the current command determining units 4-1 to 4-8 and the inverters 3-1 to 3-8 all have the same structure, here, the current command determining unit 4-1 and the inverter 3-1. Only the configuration of will be illustrated and described.

That is, in the present embodiment, as shown in FIG. 9, the current command determining unit 4-1 of the current command determining unit 4-1 in FIG. 5 is omitted, and instead of this, the current command determining unit 4- is used. 1 has a configuration in which a multiplier 34, a power command unit 35, and a current command calculation unit 36 are added.

The multiplier 34 multiplies the voltage reference Vr from the reference voltage command unit 31 and the current reference Ir common to the inverters 3-1 to 3-8, and outputs the power reference Pr.

The power command unit 35 calculates a power command Pr1 for the corresponding inverter 3-1 based on the power reference Pr from the multiplier 34 and the detected position θ from the position detector 2.

The current command calculation unit 36, based on the power command Pr1 from the power command unit 35 and the voltage waveform v from the voltage waveform storage unit 33, makes the rising and falling edges sinusoidal and corresponds to the corresponding inverter 3. The current command Ir1 of -1 is calculated.

Next, the operation of the inverter device of the present embodiment having the above configuration will be described with reference to FIG.

The description of the operation of the same parts as those in the second embodiment will be omitted, and only different parts will be described here.

In FIG. 9, when the polarity of the induced voltage waveform of the single-phase winding of the AC motor 1 is switched, it is ideally desired to be switched instantaneously, but in reality, there is some inclination.

At this time, the instantaneous power determined by voltage × current is
A valley is formed as shown by the dotted line in FIG. 10C, and the combined power of the plurality of single-phase windings of the AC motor 1 also contains ripples as shown by the dotted line in FIG. 10D.

Therefore, in the present embodiment, FIG.
As indicated by the solid line in (c), the rising and falling edges of the instantaneous power of the single-phase winding of the AC motor 1 are preliminarily inclined to form a sine wave so as to cancel each other. To do.

Specifically, in the present embodiment, the power reference Pr is obtained by multiplying the voltage reference Vr from the reference voltage command unit 31 and the current reference Ir common to the inverters 3-1 to 3-8. Is output, and the power reference Pr1 and the rotor position θ of the AC motor 1 are used to output a power command Pr1 for the inverter whose rising and falling are sinusoidal, and the power command Pr1 and the voltage from the voltage waveform storage unit 33 are output. Based on the waveform v, the current command Ir of each inverter 3-1 to 3-8
1 is calculated by the relational expression Ir1 = Pr1 ÷ v.

As a result, even when the rise and fall of the induced voltage of the single-phase winding of the AC motor 1 has a slope,
The ripple of combined power can be suppressed.

As described above, in the inverter device of this embodiment, the same effects as those of the second embodiment can be obtained, and in addition, each inverter 3-1 to 3-8
Based on the common current reference and voltage reference (inverter output reference), the detected position of the rotor of the AC motor 1, and the voltage waveform stored in the voltage waveform storage unit 33, the rise of the instantaneous power of the corresponding inverter is determined. Since the falling is made sinusoidal and the current command is generated so as to cancel the fluctuation of the instantaneous power with other inverters,
Even if the rise of the induced voltage in the single-phase winding of the AC motor has a slope, the ripple of the combined power can be suppressed.

[0110]

As described above, according to the inverter device of the present invention, even if the induced voltage waveform of the single-phase winding of the AC motor deviates from the square wave due to the influence of the armature reaction, The instantaneous electric power can be set to a constant value, and the combined electric power of the plurality of single-phase windings does not include ripples, so that the torque ripple can be suppressed.

Further, even when the induced voltage of the single-phase winding of the AC motor has a rising edge, it is possible to cancel out the instantaneous power of the other phase and suppress the ripple of power as a whole.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing an internal configuration example of an inverter and a current command determination unit in the inverter device of the first embodiment.

FIG. 3 is a waveform diagram for explaining the operation of the inverter device according to the first embodiment.

FIG. 4 is a block diagram showing a second embodiment of an inverter device according to the present invention.

FIG. 5 is a block diagram showing an internal configuration example of an inverter and a current command determination unit in the inverter device of the second embodiment.

FIG. 6 is a block diagram showing an internal configuration example of an inverter and a current command determination unit in an inverter device according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing an internal configuration example of an inverter and a current command determination unit in an inverter device according to a fourth embodiment of the present invention.

FIG. 8 is a waveform diagram for explaining the operation of the inverter device according to the fourth embodiment.

FIG. 9 is a block diagram showing an internal configuration example of an inverter and a current command determination unit in an inverter device according to a fifth embodiment of the present invention.

FIG. 10 is a waveform chart for explaining the operation of the inverter device according to the fifth embodiment.

FIG. 11 is a block diagram showing a configuration example of a conventional PWM inverter device.

[Explanation of symbols]

1 ... AC motor 2 ... Position detector 3-1 to 3-8 ... Inverter 4-1 to 4-8 ... Current command determination unit 5 ... Motor control unit 21 ... Current control unit 22 ... PWM control unit 23 ... Inverter section 24 ... Current detector 25 ... Voltage detector 31 ... Reference voltage command section 32, 36 ... Current command calculator 33 ... Voltage waveform storage unit 34 ... Multiplier 35 ... Power command unit.

Claims (5)

(57) [Claims] 1. A inverter device for driving an AC motor having a plurality of single-phase winding as a polyphase winding that generates a rotating magnetic field performs current control based on the current reference, pulse width modulation system <br / > A plurality of inverters for supplying alternating current to the plurality of single-phase windings of the alternating current motor to generate the rotating magnetic field to drive the alternating current motor, and are provided corresponding to the respective inverters, respectively. A current command determining means for individually giving a current command to the inverter, and a voltage detecting means for detecting the voltage of the single-phase winding of the AC motor, the current command determining means, the current reference common to each inverter and Based on the voltage reference and the detected voltage from the voltage detecting means, the instantaneous power of the corresponding inverter is calculated.
An inverter device comprising current command calculation means for calculating a current command so as to keep it constant . 2. A inverter device for driving an AC motor having a plurality of single-phase winding as a polyphase winding that generates a rotating magnetic field performs current control based on the current reference, pulse width modulation system <br / > A plurality of inverters for supplying alternating current to the plurality of single-phase windings of the alternating current motor to generate the rotating magnetic field to drive the alternating current motor, and are provided corresponding to the respective inverters, respectively. The inverter includes a current command determining unit that individually gives a current command, and a position detecting unit that detects a rotor position of the AC motor, and the current command determining unit is a unit of the AC motor according to each load current value. The generated voltage waveform of the phase winding is stored in advance, and a voltage waveform corresponding to the current reference common to each of the inverters and the position detected by the position detection means is generated. Based on the voltage waveform storage means, the current reference and voltage reference common to each of the inverters, and the voltage waveform from the voltage waveform storage means , a current command is calculated so as to keep the instantaneous power of the corresponding inverter constant. An inverter device comprising a current command calculation means. 3. The inverter device according to claim 2, further comprising voltage detecting means for detecting a voltage of a single-phase winding of the AC motor, and detecting from the voltage detecting means during operation of the AC motor. An inverter device comprising: learning means for updating the current waveform pattern of the voltage waveform storage means based on the voltage. An inverter apparatus for driving an AC motor having a plurality of single-phase winding as claimed in claim 4] polyphase winding that generates a rotating magnetic field performs current control based on the current reference, pulse width modulation system <br / > A plurality of inverters for supplying alternating current to the plurality of single-phase windings of the alternating current motor to generate the rotating magnetic field to drive the alternating current motor, and are provided corresponding to the respective inverters, respectively. The inverter includes a current command determining unit that individually gives a current command, and a position detecting unit that detects a rotor position of the AC motor, and the current command determining unit is a unit of the AC motor according to each load current value. The generated voltage waveform of the phase winding is stored in advance, and a voltage waveform corresponding to the current reference common to each of the inverters and the position detected by the position detection means is generated. A pressure waveform storage means and a power reference from a current reference and a voltage reference common to each of the inverters are calculated,
And, based on the power reference and the detected position from the position detecting means, a power command calculating means for calculating a power command of the corresponding inverter whose rising and falling are linear, and from the power command calculating means. Based on the power command and the voltage waveform from the voltage waveform storage means, another
An inverter device comprising: a converter and a current command calculation means for calculating a current command so as to cancel out fluctuations in instantaneous power . An inverter apparatus for driving an AC motor having a plurality of single-phase winding as a 5. polyphase winding that generates a rotating magnetic field performs current control based on the current reference, pulse width modulation system <br / > A plurality of inverters for supplying alternating current to the plurality of single-phase windings of the alternating current motor to generate the rotating magnetic field to drive the alternating current motor, and are provided corresponding to the respective inverters, respectively. The inverter includes a current command determining unit that individually gives a current command, and a position detecting unit that detects a rotor position of the AC motor, and the current command determining unit is a unit of the AC motor according to each load current value. The generated voltage waveform of the phase winding is stored in advance, and a voltage waveform corresponding to the current reference common to each of the inverters and the position detected by the position detection means is generated. A pressure waveform storage means and a power reference from a current reference and a voltage reference common to each of the inverters are calculated,
Also, based on the power reference and the position detected by the position detecting means, a power command calculating means for calculating a power command of the corresponding inverter whose rising and falling are sinusoidal, and the power command calculating means. On the basis of the power command and the voltage waveform from the voltage waveform storage means , the fluctuations in the instantaneous power of the corresponding inverters are canceled out.
Inverter apparatus characterized by comprising a current command calculating means for calculating a sea urchin current command.