JP2002354815A - Pwm cycloconverter and method of controlling input current thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of controlling current and voltage of a PWM cycloconverter which enables the proper current application control of the current and the voltage even if three-phase AC voltages are unbalanced. SOLUTION: Instantaneous values of three-phase AC voltages are detected and converted into three-phase AC currents. Positive-phase sequence components and negative-phase sequence components of the three-phase currents are extracted to generate positive-phase sequence current commands and negative-phase sequence current commands. The negative-phase sequence current commands are deducted from the positive-phase sequence current commands to obtain current commands for the three- phase unbalance compensation which are used for determining current sharing factors to practice the current control of a PWM cycloconverter. In order to extract the positive-phase sequence components and the negative-phase sequence components, a method wherein the three-phase-two-phase conversion is practiced and positive-phase sequence components and negative-phase sequence components of two-phase currents are extracted, and a method wherein positive-phase sequence components and negative- phase sequence components of the three-phase currents are directly extracted without the conversion, are proposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter for driving an AC motor at a variable speed, and particularly to a pulse width modulation (P
The present invention relates to a power conversion method of a WM) control method.

[0002]

2. Description of the Related Art FIG. 11 is a block diagram of a conventional example of a PWM cycloconverter. The PWM cycloconverter is
It is composed of a power circuit, a control system circuit, and a drive circuit. The power circuit includes a three-phase AC power supply 1, an input LC filter 2, a bidirectional semiconductor switch group 3, an AC motor 4, and a load 5. The input LC filter 2 removes high frequency noise.

The control system circuit includes an A / D converter 6, a phase detector 7, a current control block 13, an input voltage determiner 10, a PW
An M voltage control circuit 9 is provided. The A / D converter 6 detects instantaneous values Er, Es, Et of the input voltage. Phase detector 7
Detects the phase θ _i of the R phase of the three-phase input voltage. The input voltage determiner 10 receives the instantaneous values Er, Es, Et of the input voltage, and as the instantaneous values, the line voltage maximum value ΔEmax and the intermediate value ΔEmid
And outputs it to the PWM voltage controller 9. The current control block 13 includes a three-phase sine wave waveform generator 11 and a current reference calculator.
12 is provided. The three-phase sine waveform generator 11 generates a sine-wave current command from θ _i detected by the phase detector 7 and outputs the current command to the current reference calculator 12. The current reference calculator 12 outputs a current reference waveform Iref from a three-phase sine wave. The PWM voltage controller 9 receives, for example, output voltage commands Vuc, Vvc, Vwc obtained from V / F control, and generates a PWM control signal. The drive circuit 8 outputs a drive signal based on the PWM control signal to operate the bidirectional semiconductor switch group 3, and passes the currents Iu, Iv, Iw of each phase to the AC motor 4 to drive the load 5 by the motor 4. .

FIG. 11 shows a bidirectional semiconductor switch group 3
Is modeled by one switch. However, as a conventional example of a bidirectional semiconductor switch group, a current can flow in only one direction, and each of them can be independently turned on / off.
A bidirectional semiconductor switch group in which a plurality of bidirectional semiconductor switches each configured by combining two unidirectional semiconductor switches that can be turned off is used.

In a control system circuit for controlling the connection of such a bidirectional semiconductor switch group, the following current control block 13 is generally used as a controller for the current on the input side. FIG. 12 is a detailed view of the three-phase sine waveform generator 11. First R the phase angle theta _i of the input voltage, S, T phase 3-phase reference sine wave sin [theta _i which respectively 120 displaced with respect _{to, sin [θ i - (2π} /
3)], and refer to the ROM table storing the values of sin [θ _i- (2π / 3)] to obtain these values, and send them to the current reference calculator 12.
In the current reference calculator 12, the phase current (abbreviated as Nmax) which becomes the maximum value among the three input phases, and the phase current (Nm
id), the minimum phase current (abbreviated as Nmin), and the phase current having the maximum absolute value (abbreviated as Nbase), and the current reference Iref is obtained from the following equation (1). Output to PWM voltage controller. If Nmax is Nbase, then Iref = Nmid / Nmin. If Nmin is Nbase, Iref = Nmid / Nmax. ) Intermediate phase voltage (abbreviated as Emid),
Find the minimum phase voltage (abbreviated as Emin) and the phase voltage (abbreviated as Ebase) with the maximum absolute value, and obtain the maximum line voltage ΔEmax
And the intermediate value ΔEmid are calculated by the following equations (2) and (3).
The calculation result is output to the PWM voltage controller 9. ΔEmax = Emax-Emin (2) When Emax is Ebase, ΔEmid = Emax-Emid (3) When Emin is Ebase, ΔEmid = Emid-Emin (4) The PWM voltage controller 9 includes a switching pattern generator and And a switch signal generator, and calculates a PWM control signal by inputting output voltage commands Vuc, Vvc, Vwc obtained from, for example, V / F control. The switching pattern creation unit includes an output phase in which the output phase voltage command is maximum or minimum in one cycle of the carrier;
The input phase with the minimum absolute value of the input current command, the intermediate input phase,
And three bidirectional switches between the maximum input phase and ON
The order of turning on / off and the time to turn on each bi-directional switch are created and output as the switching pattern of this output phase, and the output phase voltage command is intermediate between the output phase voltage command and the absolute value of the input current command in one carrier cycle. Creates the order of turning on / off the three bidirectional switches between the minimum input phase, the intermediate input phase, and the maximum input phase and the time for turning on each bidirectional switch as the switching pattern of the output phase .
The switch signal generator generates an ON / OFF signal for one cycle of the carrier of the nine bidirectional switches according to the input three-phase current command information, the three-phase output voltage information, and the switching pattern. This calculation method is described in Japanese Patent Application No. 11-341807 filed by the present applicant.
Hereinafter, the technology described in this publication will be referred to as a cited technology. The drive circuit 8 operates the bidirectional semiconductor switch 3 in response to the PWM control signal, and drives the load 5 by flowing the currents Iu, Iv, Iw of each phase to the AC motor 4.

FIG. 13 is a waveform diagram showing an example of input / output waveforms of the current reference calculator 12. The upper diagram is a three-phase alternating current curve, and the lower diagram is an Iref curve. The Iref curve periodically changes between 1 and 0. The cycle is a constant value of 60 °
It is. As described above, when there is no imbalance in the three-phase alternating current, the Iref curve changes regularly at a constant cycle, but when there is an imbalance, this cycle becomes irregular (see FIG. 5 described later).

[0007]

In the above-mentioned conventional system, the three-phase sine wave generator 11 outputs a three-phase balanced sine wave having the same phase as that of the input voltage of each phase using only the phase of the input voltage. Control. However, in the case of an ideal three-phase input power supply, the amplitude of each phase is the same sine wave. However, in general, each phase of the input power supply has an amplitude imbalance. There is a problem that it is difficult to obtain a desired input current in the presence of a phase imbalance of the input voltage in the output of the conventional current reference calculator 12 manufactured as described above.

Further, the input voltage is divided into three control voltages (Emax, Emid, Emin) in consideration of only the magnitude of the input voltage value, and an energizing switch and an energizing switch are used by using the divided control voltage and output voltage command. The energization time is determined and the output voltage is controlled, so that the energization switch is determined only by the input voltage. Therefore, there is a problem that it is difficult to realize various input current control methods. An object of the present invention is to solve such a conventional problem and to provide a current and voltage control method of a PWM cycloconverter capable of coping with various high-performance input current control methods.

[0009]

In order to solve the above-mentioned problems, a current control method for a PWM cycloconverter according to the present invention is characterized in that an imbalance of an input AC voltage is represented by a negative-phase component of the input AC voltage. The switch timing of the bidirectional semiconductor switch group is controlled by determining the current distribution ratio Iref so as to eliminate the component.

In the present invention, the current distribution ratio (reference current value) is generated by an input three-phase current command corrected for the negative-phase component. The present invention proposes two methods for generating a corrected input three-phase current command. The first method converts an input three-phase AC voltage into a two-phase AC voltage, extracts a two-phase positive-phase voltage component and a two-phase negative-phase voltage component, and extracts the two-phase positive-phase voltage component and the two-phase negative-phase voltage. A three-phase positive-phase current command and a three-phase negative-phase current command are generated from the components. Then, a corrected input three-phase current command is generated based on the three-phase positive-phase current command and the three-phase negative-phase current command (refer to claim 1, claim 2, and claim 3). In the second method, a three-phase AC current is calculated from the input three-phase AC voltage, a positive-phase three-phase AC current is extracted from the calculated three-phase AC current, and this positive-phase three-phase AC current is A method of generating a corrected input three-phase current command as a negative-phase input three-phase current command using a result obtained by subtracting a positive-phase input three-phase current command from the calculated three-phase AC current as a phase current command (claim) See section 5).

The first method will be further described. This way
Is the input three-phase AC voltage and the phase of the first phase of the three-phase voltage
θ_iAnd converts the input three-phase AC voltage into three-phase to two-phase
To generate a two-phase AC voltage, and from the two-phase AC voltage,
A positive-phase two-dimensional coordinate rotating in the same phase as the first phase of the three-phase voltage
Axes coordinate positive transformation to extract two-phase positive-sequence voltage with reference to mark axis
The processing is executed, and 2 extracted by the axis coordinate forward conversion processing
Phase θ of the phase positive phase voltage with respect to the positive phase two-dimensional coordinate axis_p
And the set power factor phase ψ to add the two-phase positive-phase current
Phase φ_pAnd calculate the phase φ of the two-phase positive-sequence current._pThe second
Phase θ of one phase_iIs added to the semiconductor switch group.
The positive phase of the first phase of the input current command that specifies the current to be input
Component phase θ ₁Is generated, and the absolute value of the two-phase positive-sequence voltage is
Multiplying a predetermined constant to determine whether the first phase of the input current command is positive;
Phase component amplitude E_pAnd E_psin θ₁Is the positive phase power of the first phase
Flow command I *_p1And E_psin [θ₁-(2π / 3)] and E_psin [θ₁
+ (2π / 3)] is the positive phase current command I * of the second phase, respectively._p2,
Positive phase current command I * for phase 3_p3Is determined.

The negative-phase current command is generated as follows. Previous
From the two-phase AC voltage to the first phase of the three-phase voltage
Two-phase reverse phase based on two-dimensional coordinate axes that rotate in reverse phase
Execute the axis coordinate reverse transformation process to extract the voltage and perform the axis coordinate reverse transformation.
Of the two-phase opposite-phase voltage extracted by the conversion process,
Phase θ with respect to dimensional coordinate axes_nIn addition, the power factor
Add the phase 位相 and add the phase φ_nCalculate the previous
The phase φ of the two-phase opposite-phase current_nThe phase θ of the first phase_iAdd
To specify the current to be input to the semiconductor switch group.
Of the negative phase component of the first phase of the input current command _TwoGenerate a
Multiplying the absolute value of the two-phase negative-sequence voltage by a predetermined constant
The amplitude E of the negative phase component of the input current command_nAnd E_nsin
θ_TwoWith the negative phase current command I * of the first phase_n1And E_nsin [θ_Two+ (2
π / 3)] and E_nsin [θ_Two-(2π / 3)] for the second phase
Negative phase current command I *_n2, The positive-phase current command I * for the third phase_n3Determined
You.

The first-phase positive-phase current command I
* _P1, positive phase current command I * _p2 of the second phase, a positive phase current command I * _p3 of the third phase, the first reverse-phase phase current command I * _n1, the reverse of the second phase phase current command I * _n2, negative sequence current of the third phase command I *
_n3 is subtracted for each phase to obtain a first phase, a second phase, and a third phase, respectively.
, Current commands I * ₁ , I * ₂ , I * ₃ (corrected input three-phase current commands) are generated.

Next, the second method will be described as follows. First, the three-phase AC voltages Er, Is, Et are obtained, and the three-phase AC currents Ir, Is, It are obtained by multiplying by an arbitrary positive constant. Find the positive-phase input current command from the following equation (5). Then, the positive-phase input current command is used to generate an input current command.

[0015]

(Equation 3) Here, j is a 90-degree phase advance. Further, a negative phase input current command is obtained from the following equation (6).

[0016]

(Equation 4) As the input current command, a value obtained by subtracting the negative-phase input current command from the positive-phase input current command by the following equation (7) is used.

[0017]

(Equation 5) In both the first method and the second method, the current distribution ratios Iref, ΔEmax, and ΔEmid required for PWM switching control of the semiconductor switch group are obtained as follows (claim 4 and claim 5). 6).

Current commands for first phase, second phase, and third phase
I * _1, I * _2, among the I * _3, the maximum phase current command value, the phase of the current command value is an intermediate value, the current command value is minimum phase, and the largest absolute value of the phase electric current command value For each combination of
In the phase region of the input three-phase AC voltage corresponding to the divided input AC phase region, the AC voltage value is the largest phase, the AC voltage value is the intermediate value phase, and the AC voltage value is divided. The minimum phase and the phase with the largest absolute value of the AC voltage value are set in advance, and when the current command value of each phase is given, among those current command values, the minimum value for the intermediate current command value Imid Calculate the ratio Iref of the current command value Imin, and, among the given current command values of the respective phases, the phase with the largest current command value, the phase with the intermediate current command value, and the phase with the smallest current command value. ,
The phase region of the current command corresponding to the combination of phases in which the absolute value of the current command value is the largest is determined, and the AC voltage value set in the phase region of the input three-phase voltage corresponding to the determined current command phase region Is the maximum AC voltage value, the AC voltage value is the intermediate value, the AC voltage value is the minimum value, and the AC voltage value is the maximum value.
d, a minimum value Emin, and a maximum absolute value Ebase are allocated, and ΔEmax and ΔEmid are calculated from the allocated voltage values according to the following equation.

[0019]

(Equation 6)ΔEmid = Emax-Emid when Emax is Ebase ΔEmid = Emid-Emin when Emin is Ebase (8) Three-phase PWM cycloconverter for implementing the first method
Data device is a semiconductor device composed of a plurality of bidirectional semiconductor switches.
Transfer the power of the three-phase power supply to the load through the body switches
Power circuit, three-phase voltage detector for detecting power supply voltage, power supply
Phase θ of the first phase of the voltage_iA phase detector for detecting
Three-phase AC voltage and phase detected by three-phase voltage detector
Based on the phase detected by the detector, the input three-phase power
The absolute value of the current is the absolute value of the
The ratio of the absolute value of the phase current with the smallest value, that is, the current distribution
Current control unit for generating a rate, by the three-phase voltage detection unit
By inputting the detected three-phase AC voltage,
Input voltage judgment to judge small and generate ΔEmax and ΔEmid
Section, and the current distribution rate and ΔEmax and ΔEmid.
PWM control signal to generate a PWM switching control signal
A control unit having a pressure control unit, and a PWM switching control signal.
Switching the semiconductor switches in response to a signal
Three-phase PWM cycloconverter with controlling drive
The control unit is configured to control the input three-phase AC voltage to three-phase-2.
Three-phase to two-phase conversion unit that performs phase conversion to generate a two-phase AC voltage
And the first phase of the three-phase AC voltage from the two-phase AC voltage
Two-phase positive with reference to the two-dimensional coordinate axis that rotates in phase.
Executes the axis coordinate positive conversion process to extract the phase voltage, and
Width and the position of the two-phase positive-sequence voltage with respect to the positive-sequence two-dimensional coordinate axis
From the positive phase component detection unit that outputs a phase, and the two-phase AC voltage,
Negative phase 2 rotating in the opposite phase to the first phase of the three-phase AC voltage
Axis coordinates for extracting two-phase negative-sequence voltage based on dimensional coordinate axes
Performs an inverse transformation process to determine the amplitude of the inverted phase and the two-dimensional coordinate axis of the inverted phase.
-Phase component detection for outputting the phase of the two-phase negative phase voltage with respect to
And a part. The current controller is composed of the input current controller and the current base.
A quasi-operation unit, wherein the input current control unit includes
The positive-phase secondary of the two-phase positive-phase voltage extracted by the processing;
Phase θ with respect to the original coordinate axis_pAnd the set power factor phase ψ
And the phase φ of the two-phase positive-phase current_pAnd the two phases
Positive phase current phase φ_pThe phase θ of the first phase_iAnd add
Input to specify the current input to the semiconductor switch group.
Phase θ of positive phase component of first phase of force current command₁Produces
The absolute value of the two-phase positive-sequence voltage is multiplied by a predetermined constant,
Amplitude E of positive phase component of first phase of input current command_pAnd E_p
sin θ₁Is the positive phase current command I of the first phase of the input current command.
*_p1And E_psin [θ₁-(2π / 3)] and E_psin [θ₁+ (2π /
3)] is the positive phase current command I * of the second phase, respectively._p2, The third phase
Positive-phase current command I *_p3Is determined. The input current control unit,
Furthermore, the two-phase negative-phase power extracted by the axis coordinate reverse conversion process
Phase θ of the pressure with respect to the anti-phase two-dimensional coordinate axis_nIn addition,
Add the set power factor phase ψ and add the phase
φ_nIs calculated, and the phase φ of the two-phase opposite-phase current is calculated._nThe first
Phase phase θ_iAnd input to the semiconductor switch group.
Phase component of the first phase of the input current command that specifies the current to be applied
Phase θ_TwoIs generated, and the absolute value of the two-phase reverse-phase voltage is determined as
Is multiplied by a constant to calculate the amplitude E of the negative phase component of the input current command._n
And E_n sin θ_TwoIs the inverse of the first phase of the input current command.
Phase current command I *_n1And E_nsin [θ_Two+ (2π / 3)] and E_nsi
n [θ_Two-(2π / 3)] is the negative phase current command I of the second phase, respectively.
*_n2, The positive-phase current command I * for the third phase_n3Is determined. The input
The current control unit further includes a first phase, a second phase, and a third phase.
Positive phase current command I * _p1, I *_p2, I *_p3From the first phase, the second
Phase and third phase negative phase current command I *_n1, I *_n2, I *_n3Each
The current command I * for the first phase, the second phase, and the third phase is subtracted.
₁, I *_Two, I * _ThreeGenerate

The current reference calculation unit is configured to determine which one of the first, second, and third phase current commands I * ₁ , I * ₂ , and I * ₃ has the largest current command value, The phase of one cycle of the input AC is divided into twelve phase regions for each combination of a phase in which the command value is an intermediate value, a phase in which the current command value is the smallest, and a phase in which the absolute value of the current command value is the largest. When the current command values of the current command values are given, the ratio Iref of the minimum current command value Imin to the current command value Imid of the intermediate value among those current command values is calculated, and the current command of each of the given phases is calculated. Of the values, the phase with the largest current command value, the phase with the current command value intermediate, the phase with the smallest current command value,
A phase region of the current command corresponding to a combination of phases in which the absolute value of the current command value is the largest is determined and output to the input voltage determining unit.

The input voltage judging section is provided by the current reference calculating section.
Input the divisions of the twelve phase regions, and
Phase region of input three-phase AC voltage corresponding to AC phase region
, The AC voltage value is the largest phase, and the AC voltage value is the intermediate value.
Phase, the phase with the smallest AC voltage value, and the absolute value of the AC voltage value
The large phase is set, and the phase range of the determined current command
Set in the phase region of the input three-phase voltage corresponding to
The phase with the largest current voltage value, the phase with the AC voltage value
For the phase with the smallest voltage value and the phase with the largest absolute value of the AC voltage value
The maximum value Emax of the detected AC voltage value, the intermediate value Emid,
Assign and assign the minimum value Emin and the maximum absolute value Ebase
Then, ΔEmax and ΔEmid are calculated from the obtained voltage values. (Claim
8) Three-phase PWM cycle for implementing the second method
In the converter device, the current control unit
A control unit and a current reference calculation unit, wherein the input current control unit
Generates a three-phase alternating current by multiplying the input three-phase voltage by a constant
Then, a positive-phase three-phase input current command is extracted from the three-phase AC current.
From the double of the positive-phase three-phase input current command,
The three-phase input current command is generated by subtracting the AC current, and the
The flow reference calculation unit calculates the current of the first phase, the second phase, and the third phase.
Command I *₁, I *_Two, I * _ThreeOut of which phase has the largest current command value
The phase where the current command value is the middle value, the phase where the current command value is the smallest, and
For each phase combination with the largest absolute current command value,
Is divided into 12 phase regions, and the current of each phase
When a command value is given, of those current command values,
Minimum current command value Imin with respect to intermediate current command value Imid
Is calculated, and the current finger of each given phase is calculated.
Of the command values, the phase with the largest current command value, the middle with the current command value
Value phase, current command value minimum phase, current command value absolute value
Determines the phase range of the current command corresponding to the largest phase combination
And outputs it to the input voltage determination unit.
Shows the division of 12 phase regions from the current reference calculation unit.
Input, corresponding to the phase region of the divided input AC.
In each phase region of the three-phase AC voltage,
Large phase, AC voltage intermediate value phase, AC voltage value minimum
Set the phase with the largest absolute value of the
Input three-phase power corresponding to the phase region of the determined current command
The maximum AC voltage value set in the pressure phase region is
Phase, phase with AC voltage value of intermediate value, phase with minimum AC voltage value,
For the phase with the largest AC voltage value,
Maximum value Emax, intermediate value Emid, minimum value Emin, maximum
The absolute value of Ebase, and from the assigned voltage value
Calculate ΔEmax and ΔEmid.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram of a PWM cycloconverter according to a first embodiment of the present invention. The PWM cycloconverter includes a power circuit, a control system circuit, and a drive circuit. The power circuit includes a three-phase AC power supply 1, an input LC filter 2, a bidirectional semiconductor switch group 3, an AC motor 4, and a load 5. The input LC filter 2 removes high frequency noise.

The control system circuit includes an A / D converter 6, a phase detector 7, an input voltage determiner 10, a PWM voltage control circuit 9,
A phase-to-phase converter 13, a negative phase component detector 14, a positive phase component detector 15, an input current controller 16, and a current reference calculator 12 are provided.

The A / D converter 6 calculates the instantaneous value E of the input voltage.
Detect r, Es, Et. The input voltage determiner 10 receives the instantaneous values Er, Es, Et of the input voltage, obtains a line voltage maximum value ΔEmax and a line voltage intermediate value ΔEmid as the instantaneous values, and outputs them to the PWM voltage controller 9.

The three-phase to two-phase converter 13 converts the instantaneous values Er, Es, Et of the three-phase input voltage detected by the A / D converter 6 to Ed.
The two-phase voltages s and Eqs are generated, and the obtained Eds and Eqs are output to the negative phase component detector 14 and the positive phase component detector 15. Reversed phase detector 14 of the reverse-phase voltage to input 2-phase voltage amplitude Enm, generates a phase theta _n, and sends the input current controller 16. In the same way, the positive phase component detector 15, the amplitude Epm normal phase-related voltage, and generates a phase theta _p, and sends the input current controller 16. The input current controller 16 cancels the effect of unbalanced voltage and controls the power factor of the input current to an arbitrary value from the positive phase component voltage and the negative phase component voltage and the set power factor command ψ *. Input current commands I * _R , I * _S , and I * _T that can be input to the current reference calculator 12 are generated.

The current reference calculator 12 obtains a reference value (current distribution ratio) Iref of the input current from I * _R , I * _S , and I * _T. Iref
Is the ratio of the current command value of the minimum value phase to the current command value of the phase having an intermediate value among the input three-phase current commands I * _R , I * _S , and I * _T. The input voltage determiner 10 calculates the maximum value ΔEmax and the intermediate value ΔEmid among the instantaneous voltage values, and outputs them to the PWM voltage controller 9.

The PWM voltage controller 9 receives ΔEmax, ΔEmid, and Iref and, for example, output voltage commands Vuc, Vvc, Vwc obtained from V / F control, and performs switching by applying the cited technique. A pattern is created, a switching signal is generated, and output to the drive circuit 8 as a PWM control signal. The drive circuit 8 operates the bidirectional semiconductor switch 3,
The currents Iu, Iv, Iw of each phase are supplied to the AC motor 4 to drive the load 5.

Next, an input current control method of the PWM cycloconverter according to the present invention will be described. First, the instantaneous values Er, Es, Et of the three-phase input voltage are converted by the three-phase to two-phase converter 13 to obtain two-phase voltages of Eds, Eqs. Here, the following equations (9) and (10) are three-phase to two-phase conversion from a three-phase AC coordinate system to a two-phase AC coordinate system.

[0030]

(Equation 7) FIG. 2 is a block diagram of the positive phase component detector 15. The axis coordinate positive converter 15a performs a positive axis coordinate conversion for converting the two-phase AC coordinate system into a two-phase DC coordinate system (a two-dimensional orthogonal coordinate system rotating at the same angular velocity as the three-phase AC rotating magnetic field). The axis coordinate positive conversion is performed by using an axis coordinate positive conversion matrix C2 for converting the two-phase AC coordinate system represented by the following equation (11) to the two-phase DC coordinate system.
Convert s and Eqs to Ed1 and Eq1. θ _i is the phase angle of the input three-phase alternating current, and when the angular velocity of the rotating magnetic field is ω, θ _i
i = ωt. These are first-order lag filters 15b, 1
5c, the positive-phase components Edf1 and Eqf1 of the two-phase DC coordinate system can be obtained. Amplitude detector 15
d, the phase detector 15e calculates the equation (1) using Edf1 and Eqf1.
Performs an arithmetic operation according to the amplitude and phase arithmetic expressions represented by 2),
Amplitude and phase Epm normal phase-related voltage, and generates a theta _p.

[0031]

(Equation 8) The reason for using the first-order lag filters 15b and 15c is that if there is an imbalance in the input AC voltage, the two-phase AC voltage obtained by three-phase to two-phase conversion of the input AC voltage contains a negative-phase component. It is. Therefore, when such a two-phase alternating current including the negative-phase component is subjected to the axial coordinate forward conversion represented by Expression (11), the conversion result includes the negative-phase component
A high frequency component having an angular frequency of 2ω is included. The first-order lag filters 15b and 15c remove this high-frequency component.

If the input three-phase voltage is an ideal waveform (that is, if there is no imbalance), the q component of equation (12)
Eqf1 becomes 0. Therefore, in this case, θ _p is 0
become.

FIG. 3 is a block diagram of the antiphase component detector 14. The axis coordinate inverse converter 14a performs an axis coordinate inverse transformation for converting from a two-phase AC coordinate system to a two-phase negative-phase DC coordinate system (a two-dimensional orthogonal coordinate system that rotates in reverse at the same angular velocity as the three-phase AC rotating magnetic field). . The axis coordinate inverse transform unit 14a converts Eds and Eqs into Ed2 and Eq2 by the axis coordinate inverse transform matrix C3 expressed by the following equation (13).
Convert to By passing the voltages Ed2 and Eq2, which have been subjected to the axis coordinate inverse transformation, through the first-order lag filters 14b and 14c, it is possible to obtain the negative-phase components Edf2 and Eqf2 of the two-phase DC coordinate system. The amplitude detector 14d and the phase detector 14e are Ed
Using f2 and Eqf2, a calculation is performed according to the amplitude and phase calculation formula expressed by equation (14), and the amplitude and phase Ep of the negative-sequence component voltage are calculated.
m and θ _n are generated, respectively.

[0034]

(Equation 9) The general expression for the three-phase unbalanced voltage is the space vector
It can be expressed by the following space vector equation (15). <E _RST > = <E _ps > + <E _ns > (15) In equation (15), <E _ps > and <E _ns > are a positive-phase voltage vector and a negative-phase voltage vector, respectively. Is defined as in the following equation (16).

[0035]

(Equation 10) E _pm in equation (16) the amplitude of the positive phase voltage, the E _nm amplitude of reversed phase voltages, the rotational angular velocity, t is time, the theta _p and theta _n are each delayed angle.

In the present invention, in order to cope with the unbalance of the three-phase input voltage, the current command value on the three-phase input side is determined by the following equation (17):
Use I * _{RS T} >. <I * _RST > = <I * _ps > + <I * _ns > (17) In equation (16), <I * _ps > and <I * _ns > are the positive-phase current vector and the negative-phase current vector, respectively. And the following equation (18)
Is defined as

[0037]

[Equation 11] In the above equation (17), I * _pm is the amplitude of the positive-phase current command, I * _nm is the amplitude of the negative-phase current command, and φ * _p and φ * _n are the delay angles. Further, the general expression of the active power P in the steady state is as shown in the following expression (19).

[0038]

(Equation 12) The active power P in the above equation (19) can be divided into two components as in the following equation (20). P = Constant power component + Ripple power component (20) In the present embodiment, the amplitude of the positive-phase current command is changed so that the power factor = cos (ψ * _pf ) while maintaining the active power in the steady state constant. Equation (21), and the delay angle is given by the following equation (2)
2) The amplitude of the negative phase current command is output as in the following equation (23), and the delay angle is output as in the following equation (24).

[0039]

(Equation 13) In the above equations (21) and (23), is an arbitrary constant.

FIG. 4 is a block diagram showing the input current controller 16 of this embodiment. As described above with reference to FIG. 1, the input current controller 16 determines the set power factor command, the phase θ _i of the input three-phase AC output from the phase detector 7, the positive phase component voltage, and the negative phase component. Unbalance correction current command value based on voltage amplitudes E _pm and E _nm and delay angles θ _p and θ _{n of} positive-phase and negative-phase components.

[0041]

[Equation 14] Is output.

To this end, the input current controller 16 includes a normal-phase processing section, a negative-phase processing section, and an addition section for adding the outputs of these processing sections. The normal phase processing unit includes blocks indicated by reference numbers including p in FIG. The reverse phase processing unit includes blocks indicated by reference numbers including n in FIG. The adder is a functional part having three adders 45R, 45S, and 45T corresponding to the R, S, and T phases in the figure.

The positive-phase processing unit includes a multiplier 42p, an adder 43
p and 44p, three-phase sine wave generator 41p, multiplier 44
Rp, 44Sp and 44Tp are provided. Multiplier 42p
It may be any positive constant 1 / K to input amplitude E _pm of positive phase component voltage
Multiply by f and output the amplitude I * _pm of the positive phase current command. This operation corresponds to equation (21). The adder 43p produces a positive-phase phase command phi * _p by adding the delay angle theta _p and power factor phase command [psi * _pf positive phase voltage (delay angle phi * _p of the positive-phase current command) . This addition corresponds to equation (22). Adder 44
p is a phase angle θ ₁ (phase angle of the R-phase three-phase AC current command) generated by adding the R-phase phase angle θ _i = ωt of the input three-phase AC voltage to the delay angle φ * _p. . The three-phase sine wave generator 41p is
A three-phase current command having an amplitude of 1 is generated using the phase angle θ _{1 of the} positive phase as a variable. The multipliers 44Rp, 44Sp, and 44Tp respectively multiply the three-phase current command having an amplitude of 1 by the amplitude I * _pm of the positive-phase current command output from the multiplier 42p to obtain an R phase, an S phase,
The T-phase positive-phase current commands I * _Rp , I * _Sp , and I * _Tp are generated. These operations correspond to the expression on the left side of Expression (18).

Similarly, the anti-phase processing section includes a multiplier 42n, adders 43n and 44n, multipliers 46 and 47, a three-phase sine wave generator 41n, and multipliers 44Rn, 44Sn and 44Tn.
It has. The multiplier 42n calculates the amplitude E _pm of the positive-sequence component voltage.
And multiplies it by an arbitrary explicit constant 1 / Kf to output the amplitude I * _nm of the negative-phase current command. This operation corresponds to equation (23). Adder 43n generates a reverse phase voltage of the delay angle theta _n and power factor phase command [psi * _pf and the added reverse phase phase command phi and * _n (delay angle phi * _n reverse-phase current command) . This addition corresponds to equation (24). The adder 44n adds the phase angle θ _i = ωt of the R phase of the input three-phase AC voltage to the negative phase command φ * _n to generate a negative phase sine wave phase θ ₂ . Multiplier 46,
47 is the amplitude I * _nm of the negative phase current command and the negative phase phase θ ₂
Is multiplied by a gain of -1. Three-phase sine wave generator 4
1n generates a three-phase current command having an amplitude of 1 using the phase angle −θ ₂ as a variable. Multipliers 44Rn, 44Sn, 44Tn
Multiplies the three-phase current command of amplitude 1 by −I * _nm to generate current commands I * _Rn , I * _Sn , and I * _Tn for the negative phases of the R, S, and T phases. These operations correspond to the expression on the right side of Expression (18). Finally, the three positive-phase current commands and the three negative-phase current commands are added by the adders 45R, 45S, and 45T, respectively, and the input current commands (unbalance correction current commands) I * _R , I * _S , I * _T is obtained. This addition is obtained by the equation (1)
Corresponds to 7).

The current reference computing unit 12 outputs a maximum phase current (abbreviated as Imax), an intermediate phase current (abbreviated as Imid), and a minimum phase current among the input three-phase current command values. (Abbreviated as Imin), the phase current (Ibase
The current reference Iref is obtained from the following equation (26), and is output to the PWM voltage controller. When Imax is Ibase, Iref = Imid / Imin When Imin is Ibase, Iref = Imid / Imax (26) FIG. 5 shows an example of input / output waveforms of the current reference calculator 12.
In a normal PWM cycloconverter, the phase having the maximum absolute value is supplied as a reference voltage, and the other two phases are PWM-controlled. The current reference Iref means a ratio of a current flowing in two phases (two phases excluding the Ibase phase) under PWM control.
The current reference waveform of FIG. 5 is similar to that of the prior art of FIG. 13 in that it periodically fluctuates between 0 and 1. However, in the case of FIG. 13, the current reference waveform fluctuates at a constant period (60 °), whereas in the case of FIG. 5, the current reference waveform corresponds to the imbalance of the three-phase input current command. The difference from the case of FIG. 13 is that the period of the current reference waveform varies. The PWM voltage control circuit 9 uses the current reference shown in FIG.
Since the control is performed using Iref as one of the state variables, the PWM voltage control circuit according to the present embodiment can execute the PWM control in which the influence of the imbalance of the three-phase input current command is compensated.

In the input voltage judgment unit 10, the phase voltage (abbreviated as Emax), the phase of the intermediate value (abbreviated as Emid), the phase of the minimum value (abbreviated as Emin), and the absolute value are the largest among the instantaneous voltage values. A phase voltage (abbreviated as Ebase) that becomes a value is obtained, ΔEmax and ΔEmid are obtained from Expression (2), and output to the PWM voltage controller 9.

The PWM voltage controller 9 calculates ΔEmax and ΔEm
The PWM control signal is calculated by inputting id, Iref, and output voltage commands Vuc, Vvc, Vwc obtained from V / F control, for example. The PWM voltage controller 9 determines whether the output phase voltage command is maximum or minimum in one cycle of the carrier and the input phase in which the absolute value of the input current command is minimum, intermediate, and maximum. The order of turning on / off the three bidirectional switches and the time to turn on each bidirectional switch are created and output as this output phase switching pattern, and the output phase voltage command is an intermediate output in one carrier cycle. The order of turning on / off the three bidirectional switches between the phase, the input phase with the minimum absolute value of the input current command, the intermediate input phase, and the maximum input phase, and the time to turn on each bidirectional switch Is created as a switching pattern of the output phase. The PWM voltage controller 9 further provides an ON / OFF signal for one cycle of the carrier of the nine bidirectional switches according to the input three-phase current command information, the three-phase output voltage information, and the switching pattern, that is,
Generates and outputs a PWM control signal. The drive circuit 9 is a PW
In response to the M control signal, the bidirectional semiconductor switch 3 is operated, and the currents Iu, Iv, Iw of each phase are supplied to the AC motor 4 to load 5
Drive.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram of the PWM cycloconverter according to the present embodiment. It is configured by a cycloconverter power circuit, a control system circuit, and a drive circuit of the present embodiment. The power circuit includes a three-phase AC power supply 1, an input LC filter 2, a bidirectional semiconductor switch group 3, an AC motor 4, and a load 5. The input LC filter 2 removes high frequency noise.

The control system circuit includes an A / D converter 6, a phase detector 7, an input current controller 15, a current reference calculator 12, an input voltage determiner 14, and a PWM voltage control circuit 9.
The A / D converter 6 detects instantaneous values Er, Es, Et of the input voltage. The phase detector 7 detects the R-phase voltage phase θ _i of the three-phase input voltage. The input current controller 15 receives the set power factor command ψ _pf *, the instantaneous values Er, Es, Et of the input voltage, and the input voltage phase θ _i, and controls the power factor of the input current by the operation described later. Then, a three-phase current command reference value I * _R , I * _S , I * _T capable of correcting the imbalance of the input voltage is generated and sent to the current reference calculator 12. The three-phase current command reference value is a three-phase current command having an amplitude of one. The current reference calculator 12 receives the three-phase current command reference values I * _R , I * _S , and I * _T, and outputs a current reference waveform Iref to the PWM voltage controller 9. The input voltage determiner 14 receives the instantaneous voltage values Er, Es, Et, and obtains a maximum line-to-line value ΔEmax among the instantaneous voltage values Er, Es, Et.
And an intermediate value ΔEmid between the lines are obtained and output to the PWM voltage controller 9. The PWM voltage controller 9 calculates ΔEmax and ΔEmid
Iref and the output voltage command Vu obtained from V / F control, for example.
PW for performing PWM control by inputting c, Vvc, and Vwc
Generate an M control signal. The drive circuit 8 outputs a drive signal in response to the PWM control signal, operates the bidirectional semiconductor switch 3, and drives the load 5 by flowing the currents Iu, Iv, Iw of each phase to the AC motor 4.

Next, an input current control method of the PWM cycloconverter according to the present invention will be described. First, the phase θ _i of the three-phase input voltage and the power factor command ψ * _pf are
Send to 5. The input current controller 15 outputs the reference values I * _R , I * _S , I *
_Ask for _T. The reference values I * _R , I * _S , I * _T are determined depending on the control purpose. For example, when the input power factor is set to an arbitrary value, the reference values I * _R , I * _S , and I * _T are calculated according to the following equation (27). The calculation of Expression (27) is performed by the circuit of FIG.

[0051]

(Equation 15) FIG. 7 is a block diagram of a first embodiment of the input current controller according to the present invention. This embodiment is an embodiment of an input current controller that generates a three-phase current command having an ideal sine waveform from an input three-phase voltage by adding a power factor phase command ψ * _pf to an input voltage phase θ _i .

The input current controller 15 of this embodiment comprises adders 71 and 73, a subtractor 72, a ROM table 74R,
74S and 74T are provided. The adder 71 obtains a current command phase by adding the power factor phase command ψ * _pf to the input voltage phase θ _i . The subtracter 72 and the adder 73 generate the phases of the S-phase and T-phase current commands, respectively, using the current command phase θ _i + ψ * _pf as the phase of the R phase. ROM tables 74R, 74
S and 74T are ROMs that store a trigonometric function table and function as a three-phase sine waveform generator. These ROMs include an adder 71, a subtractor 72, and an adder 7 respectively.
3 corresponding to the phase given from R phase, S phase, and T phase.
Generates phase current command reference values I * _R , I * _S , I * _T.

FIG. 8 shows a second example of the input current controller of the present embodiment.
FIG. 4 is a block diagram of an embodiment of FIG. The present embodiment is a block of an input current controller for performing current control for the purpose of correcting imbalance of input three-phase voltages. In this embodiment, after the input three-phase voltage is multiplied by a constant to convert it into a three-phase AC current, the positive-phase component is extracted, and the positive-phase component of the three-phase input current command is converted to the negative-phase component of the three-phase AC current. Is subtracted to generate a current command for imbalance correction.

The input current controller of the present embodiment comprises a multiplier 81
R, 81S, 81T and 90-degree phase conversion filter 82
R, 82S, 82T, subtractors 83a, 83b, multipliers 84a, 84b, 84c, 84d, subtractors 85a, 85
b, multipliers 86a and 86b, subtractors 87a and 87b, and a multiply-adder 88.

The multipliers 81R, 81S and 81T are provided with A / D
The input voltage Er, Es, Et detected from the converter is multiplied by an arbitrary positive constant Im to generate input three-phase current values Ir, Is, It.
The 90-degree phase conversion filters 82R, 82S, 82T are:
The phase of Ir, Is, It is converted by 90 degrees, respectively, and Ir∠90, Is∠
90, It∠90 is generated. Here, ∠90 represents a vector obtained by rotating the phase by 90 °, and corresponds to multiplying by j in a complex representation.

The subtracter 83a subtracts the output of the 90-degree phase conversion filter 82S from the output of the 90-degree phase conversion filter 82R. The subtracter 83b converts the output of the 90-degree phase conversion filter 82T into a 90-degree phase conversion filter 82T.
The output of S is subtracted.

The multipliers 84b and 84c multiply the outputs of the multipliers 83a and 83b by [2.31 / ² ] ^-1 and output the result. The multipliers 84a and 84d multiply the outputs of the multipliers 81R and 81T by １ ／ and output the result.

The subtractor 85a subtracts the output of the multiplier 84c from the output of the multiplier 84a. The subtractor 85b subtracts the output of the multiplier 84b from the output of the multiplier 84d.

Multipliers 86a and 86b multiply the outputs of subtracters 85a and 85b by 2 and output the multiplication results. The subtracters 87a and 87b output the R-phase current value Ir and the T-phase current value It from the outputs of the multipliers 86a and 86b, respectively.
Is subtracted, and the results are respectively referred to as R-phase current commands I * _R and T
Output as phase current command I * _T. The multiplication / addition unit 88 multiplies the outputs I * _R and I * _T of the subtracters 87 a and 87 b by −1, adds the multiplication results, and outputs the result as an S-phase current command I * _S.

The outputs Irp and Itp of the subtractors 85a and 85b in FIG. 8 are expressed by the following equation (28). This is the input current command for the positive phase of the R phase and the T phase.

[0061]

(Equation 16) Equation (28) is equivalent to the first and third rows of equation (5).

The multipliers 86a and 86b and the subtracter 87 shown in FIG.
a, 87b, the input current commands I * _R , I * _S , I * by subtracting the R-phase and T-phase input currents from the R-phase and T-phase positive-phase input current commands by the calculation by the multiplying / adding unit 88. _{As T} , a value obtained by the following equation (29) is obtained.

[0063]

[Equation 17] In this manner, the input current commands I * _R , I * _S , and I * _T are obtained.

The current reference calculator 12 outputs a phase current (abbreviated as Imax), an intermediate phase current (abbreviated as Imid), and a minimum phase current (Imin) in the input three-phase current command. ), And the phase current (abbreviated as Ibase) whose absolute value becomes the maximum value is determined, and the current reference Iref is obtained from Expression (30), and PWM is obtained.
Output to the voltage controller. When Imax is Ibase, Iref = Imid / Imin. When Imin is Ibase, Iref = Imid / Imax. .

FIG. 9 shows that the phase currents are Imax, Imid, Imin, Ibas
6 is a correspondence table between a phase set e and a phase region Si. For example, in FIG. 13, the three-phase current command has a balanced ideal shape. In this case, if one cycle of the current command is equally divided by 30 °, the magnitude relation of each phase current command in each phase region is determined. For example, in a phase section i (a section with a phase angle of 0 to 30 °) in FIG.
The phases of id and Imin are T phase, R phase and S phase, and the phase of Ibase is S phase. Further, the phase section iv (phase angles 90 to 12) in FIG.
0 ° section), the phases of Imax, Imid and Imin are R
In the phase, the S phase, and the T phase, the phase of Ibase is the R phase.

As described above, when the three-phase current commands are balanced, each phase current command has a unique magnitude relationship in each phase section divided at equal intervals. But,
When the three-phase current commands are not balanced, as described above with reference to FIG. 5, the phase sections in which each phase current command has a unique magnitude relationship are not necessarily equally spaced. However, the phase sections can be divided so that the current commands in each phase section have a unique magnitude relationship.
The table of FIG. 9 is a table showing the correspondence between the phase regions Si partitioned in this way and the magnitude relationships of the respective phase current commands. Therefore, Imax, Imid, Imin, Ib
By determining ase, the corresponding phase region Si can be output. Next, the input voltage determiner 14 will be described.

FIG. 10 is a table showing the correspondence between each phase region Si and the input voltage maximum value Emax, intermediate value Emid, minimum value Emin, and phase having the absolute value Ebase of the input voltage of the phase having the maximum absolute value. It is. The input voltage and the current command have a fixed relationship (for example,
The amplitude of the current command is obtained by multiplying the input voltage by a positive constant, and the phase of the current command is obtained by adding the power factor phase command to the phase of the input voltage. Can be created in advance.
FIG. 10 is the table.

The input voltage judging unit 14 calculates the three-phase input voltages Er, E
Using s, Et and the area Si of the three-phase current command input from the current reference calculator 12, Emax, Emi
Find the phases of d, Emin and Ebase. Further, the maximum value between the lines and the intermediate value between the lines among the instantaneous voltage values are obtained from the following equations (30) and (31), and output to the PWM voltage controller.

[0069]

(Equation 18) If Emax (Si) is Ebase (Si), then Emin (Si) is Ebase (Si). (31) where Emax (S _j ) is determined by the three-phase command area Si.
Emid (S _j ) is the input voltage of the phase corresponding to Emid, and Emin (S _j ) is the input voltage of the phase corresponding to Emin.

In the PWM voltage controller 9, the output voltage commands Vuc, Vv
c, bidirectional semiconductor switch 3 using Vwc and current reference Iref
And outputs a drive signal. For example, output voltage commands Vuc, Vvc, Vwc obtained from V / F control are input to the PWM voltage controller 9. The drive circuit 9 operates the bidirectional semiconductor switch 3 to drive the load 5 by passing the currents Iu, Iv, Iw of each phase to the AC motor 4.

[0071]

As described above, according to the present invention, even when a phase imbalance of the input power source occurs, the influence can be suppressed, and control can be performed without distortion of the input current waveform. In addition, when controlling the output voltage, the energizing switch is conventionally determined only for the magnitude of the input voltage value.Therefore, when realizing various control methods such as phase imbalance correction of the input voltage and input power factor control, the input switch is not required. Although there was a problem that the current control became difficult, the present invention divides the voltage based on the input current command, so that the input current can be controlled without distorting the input current waveform.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a PWM cycloconverter according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing an embodiment of the positive phase component detector 14 shown in FIG. 1 according to the present invention.

FIG. 3 is a circuit diagram showing an embodiment of the present invention of the antiphase component detector 15 shown in FIG. 1;

FIG. 4 is a circuit diagram showing one embodiment of the present invention of the input current controller 16 shown in FIG. 1;

FIG. 5 is a current reference calculator 1 shown in FIG. 1 of the present invention.
FIG. 4 is a waveform chart showing an example of input / output waveforms of FIG.

FIG. 6 is a block diagram showing a configuration of a second embodiment of the PWM cycloconverter of the present invention.

7 is a circuit diagram showing a configuration of an embodiment of the present invention of the input current controller 15 shown in FIG. 6;

FIG. 8 is a circuit diagram showing a configuration of an input current controller 15 shown in FIG. 6 according to an embodiment of the present invention.

FIG. 9 shows the input current controller 1 shown in FIG. 6 of the present invention.
2 is a diagram showing one example of a specific selection method of a phase region Si in FIG.

FIG. 10 is a diagram showing a specific example of a system for performing voltage division in the current reference calculator 14 shown in FIG. 6 of the present invention.

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

FIG. 12 is a circuit diagram showing one embodiment of a conventional three-phase sine waveform generator 11 shown in FIG. 11;

FIG. 13 is a waveform diagram showing an example of input / output waveforms of the current reference calculator 12 shown in FIG. 11 of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 3-phase AC power supply 2 3-phase input filter 3 Bidirectional semiconductor switch matrix 4 AC motor 5 Load 6 A / D converter 7 Phase detector 8 Drive circuit 9 PWM voltage controller 10 Input voltage judgment device 11 3-phase sine waveform generation Unit 11a ROM table 12 current reference calculator 13 current control block 14 input voltage determiner 15 input current control controller 41p, 41n three-phase sine wave generator 42p, 42n multiplier 43p, 43n adder 44p, 44n adder 44Rp, 44Sp, 44Tp multiplier 44Rn, 44Sn, 44Tn multiplier 45R, 45S, 45T Adder 46, 47 Multiplier (gain-1) 71 Adder 72 Subtractor 74R, 74S, 74T ROM table 81R, 81S, 81T multiplier 82R , 82S, 82T 90-degree phase conversion filter 83a, 83b, 85a, 85 b Subtractor 84a, 84b, 84c, 84d Multiplier 86a, 86b Multiplier 87a, 87b Subtractor 88 Multiplying adder

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hidenori Hara 2-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu City, Fukuoka Prefecture Inside Yaskawa Electric Co., Ltd. (72) Inventor Eiji Watanabe 2-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu City, Fukuoka Prefecture F-term in Yaskawa Electric Co., Ltd. (Reference) 5H576 BB05 BB10 CC05 DD02 DD04 EE01 EE11 HA01 HB04 JJ03 JJ16 JJ26 KK06 LL24 LL39 5H750 AA10 BA01 BA06 CC00 CC05 DD14 DD18 DD26 DD27 EE01 FF02 FF04

Claims (11)

[Claims] 1. A semi-conductor comprising a plurality of bidirectional semiconductor switches.
Three-phase power supply by PWM switching control of conductor switches
-Phase PWM cyclo-converter for transmitting electric power to load
In the current control method, the current control method inputs the semiconductor switch group.
A current command generator that generates an input current command that specifies the current
The current command generation procedure includes a positive-phase current command generation.
The positive-phase current command generation procedure includes an input three-phase voltage and a phase θ of a first phase of the three-phase voltage._iDetect
And converts the input three-phase voltage into three-phase to two-phase to obtain a two-phase AC voltage.
Generating from the two-phase AC voltage the same phase as the first phase of the three-phase voltage
Two-phase positive-phase power based on two-dimensional positive-phase coordinate axes rotating in phase
Executes the axis coordinate positive conversion process for extracting the pressure, and calculates the two-phase positive phase voltage extracted by the axis coordinate
Phase θ with respect to the normal phase two-dimensional coordinate axis_pIs set to
Add the power factor phase ψ and add the phase φ of the two-phase positive-phase current_pCalculate
And the phase φ of the two-phase positive-sequence current_pThe phase θ of the first phase_iTo
Add and specify the current to be input to the semiconductor switch group
Phase θ of the positive phase component of the first phase of the input current command₁Raw
Multiplying the absolute value of the two-phase positive-sequence voltage by a predetermined constant
Amplitude E of positive phase component of first phase of input current command_pAnd E_psin θ₁With the positive-phase current command I * of the first phase_p1And E_psin
[θ₁-(2π / 3)] and E _psin [θ₁+ (2π / 3)]
Positive phase current command I * for phase 2_p2, The positive-phase current command I * for the third phase
_p3Characterized in that it includes a procedure for determining
Input current control method for micro converter. 2. The method according to claim 1, wherein the current command generating step includes a negative-phase current command.
Generating a negative-phase current command from the two-phase AC voltage to a first phase of the three-phase voltage.
Phase inversion with reference to two-dimensional coordinate axes that rotate in opposite phase
Executing the axis coordinate reverse transformation process for extracting the phase voltage,
Phase θ with respect to the above-mentioned two-dimensional coordinate axis_nIn the above,
Phase of the two-phase antiphase current_nTo
Is calculated, and the phase φ of the two-phase reverse-phase current is calculated._nThe phase θ of the first phase_iTo
Add and specify the current to be input to the semiconductor switch group
Phase θ of the negative phase component of the first phase of the input current command_TwoRaw
Multiplying the absolute value of the two-phase negative-sequence voltage by a predetermined constant
Amplitude E of negative phase component of input current command_nAnd E_nsin θ_TwoWith the negative phase current command I * of the first phase_n1And E_nsin
[θ_Two+ (2π / 3)] and E _nsin [θ_Two-(2π / 3)]
Negative phase current command I * for phase 2_n2, The positive-phase current command I * for the third phase
_n3The PWM according to claim 1, comprising a procedure for determining
Input current control method for cycloconverter. 3. The first-phase positive-phase current command I * _p1 ,
Positive phase current command I * _p2 for the third phase, positive phase current command I * _{p3 for} the third phase
, The negative phase current command I * _n1 of the first phase, the negative phase current command I * _{n2 of} the second phase, and the negative phase current command I * _n3 of the third phase are subtracted for each phase, and _3. The PW according to claim ₂ , wherein the current commands I * ₁ , I * ₂ , and I * ₃ of the first phase, the second phase, and the third phase are generated. 4.
An input current control method for an M cycloconverter. 4. A phase having a maximum current command value and an intermediate current command value among current commands I * ₁ , I * ₂ , and I * ₃ of a first phase, a second phase, and a third phase. The phase of one cycle of the input AC is divided for each combination of the phase, the phase having the smallest current command value, and the phase having the largest absolute value of the current command value, and corresponds to the phase region of the divided input AC. In the phase region of the input three-phase AC voltage, the phase having the largest AC voltage value,
When the AC voltage value is the intermediate value phase, the AC voltage value is the minimum phase, and the AC voltage value is the maximum value, the current command value for each phase is given. Among them, the ratio Iref of the minimum current command value Imin to the current command value Imid of the intermediate value is calculated, and among the given current command values of the respective phases, the phase in which the current command value is the largest, the current command value Determines the phase region of the current command corresponding to the combination of the phase with the intermediate value, the phase with the smallest current command value, and the phase with the largest absolute value of the current command value, and the input corresponding to the phase region of the determined current command The phase with the largest AC voltage value set in the phase region of the three-phase voltage,
For the phase where the AC voltage value is an intermediate value, the phase where the AC voltage value is the smallest, and the phase where the absolute value of the AC voltage value is the largest, the detected AC voltage value maximum value Emax, intermediate value Emid, minimum value Emin, Assign the maximum absolute value Ebase, and from the assigned voltage value, ΔEmax, ΔEmid
The current distribution ratio and ΔEmax, ΔEm are calculated using the ratio Iref as the current distribution ratio.
4. The input current control method for a PWM cycloconverter according to claim 3, wherein said semiconductor switch group is subjected to PWM switching control based on id. (Equation 1) ΔEmid = Emax-Emid when Emax is Ebase ΔEmid = Emid-Emin when Emin is Ebase 5. A current control method for a three-phase PWM cycloconverter for performing PWM switching control of a semiconductor switch group including a plurality of bidirectional semiconductor switches to transmit power of a three-phase power supply to a load. A current command generation procedure for generating an input current command for specifying a current to be input to the semiconductor switch group, wherein the current command generation procedure generates a three-phase AC current by multiplying an input three-phase voltage by a constant; Extracting a positive-phase three-phase input current command from the three-phase AC current; subtracting the three-phase AC current value from twice the positive-phase three-phase input current command to generate a three-phase input current command; An input current control method for a PWM cycloconverter, wherein a PWM switching control of the semiconductor switch group is performed using a three-phase input current command. 6. The phase having the largest current command value among the three-phase input current commands I * ₁ , I * ₂ , and I * ₃ of the first phase, the second phase, and the third phase, and the current command value. Is the phase with the intermediate value, the phase with the minimum current command value,
And the phase of one cycle of the input AC is divided for each combination of phases in which the absolute value of the current command value is the largest, and in the phase region of the input three-phase AC voltage corresponding to the divided input AC phase region, Phase with the highest voltage value,
When the AC voltage value is the intermediate value phase, the AC voltage value is the minimum phase, and the AC voltage value is the maximum value, the current command value for each phase is given. Among them, the ratio Iref of the minimum current command value Imin to the current command value Imid of the intermediate value is calculated, and among the given current command values of the respective phases, the phase in which the current command value is the largest, the current command value Determines the phase region of the current command corresponding to the combination of the phase with the intermediate value, the phase with the smallest current command value, and the phase with the largest absolute value of the current command value, and the input corresponding to the phase region of the determined current command For the phase where the AC voltage value set in the phase region of the three-phase voltage is the maximum, the AC voltage is the intermediate value, the AC voltage is the minimum, and the absolute value of the AC voltage is the maximum, Assign the maximum value Emax, intermediate value Emid, minimum value Emin, and maximum absolute value Ebase of the detected AC voltage value, Ri ΔEmax from rely obtained voltage value according to the following equation, ΔEmid
The current distribution ratio and ΔEmax, ΔEm are calculated using the ratio Iref as the current distribution ratio.
6. The input current control method for a PWM cycloconverter according to claim 5, wherein said semiconductor switch group is subjected to PWM switching control based on id. (Equation 2) ΔEmid = Emax-Emid when Emax is Ebase ΔEmid = Emid-Emin when Emin is Ebase 7. A current control method for a three-phase PWM cyclo-converter for transmitting a power of a three-phase power supply to a load by performing PWM switching control on a semiconductor switch group including a plurality of bidirectional semiconductor switches. A current command generation procedure for generating an input current command for designating a current to be input to the semiconductor switch group, wherein the current command generation procedure detects a phase of a first phase of an input three-phase AC voltage; The power factor phase command is added to the phase of the first phase of the AC voltage to generate the phase of the first phase of the input three-phase current command, and a sine having the phase of the first phase of the input three-phase current command Generating a three-phase current command by generating a wave, using the sine wave as a first phase current command, and delaying the phase by 120 ° with respect to the first phase current command to generate a three-phase current command. Converter input current control Your way. 8. A half comprising a plurality of bidirectional semiconductor switches.
Transfers the power of a three-phase power supply to a load through a group of conductor switches
Power circuit, a three-phase voltage detector for detecting the power supply voltage,
Phase θ of the first phase of the source voltage_iBefore the phase detector to detect
The three-phase AC voltage detected by the three-phase voltage detector and the potential
Based on the phase detected by the phase detector, input three phases
The minimum value of the current value of the current with respect to the phase current value of the intermediate value phase
Generate the ratio of the phase current values of the two phases, that is, the current distribution ratio
A current control unit, a three-phase voltage detected by the three-phase voltage detection unit;
Input the three-phase AC voltage, determine the magnitude of the three-phase AC voltage,
An input voltage determining unit that generates ΔEmax and ΔEmid; and
Input the current distribution ratio and ΔEmax and ΔEmid
Has a PWM voltage control unit that generates a switching control signal
Control unit that responds to the PWM switching control signal.
A drive unit for switching the semiconductor switch group.
In the three-phase PWM cycloconverter device having
The control unit converts the input three-phase AC voltage to three-phase to two-phase and converts the two-phase AC voltage
A three-phase-to-two-phase converter that generates the same phase as the first phase of the three-phase AC voltage from the two-phase AC voltage
Two-phase positive-phase power based on two-dimensional positive-phase coordinate axes rotating in phase
Execute the axis coordinate positive conversion process to extract the pressure, and
And the phase of the two-phase positive-sequence voltage with respect to the positive-phase two-dimensional coordinate axis
And a positive-phase component detecting unit that outputs a first phase of a three-phase AC voltage from the two-phase AC voltage.
Phase inversion with reference to two-dimensional coordinate axes that rotate in opposite phase
Executes the axis coordinate reverse transformation process to extract the phase voltage,
Width and the position of the two-phase negative-sequence voltage with respect to the negative-sequence two-dimensional coordinate axis
A negative phase component detection unit that outputs a phase, wherein the current control unit includes an input current control unit and a current reference calculation unit.
The input current control unit extracts by an axis coordinate positive conversion process.
Of the obtained two-phase positive-sequence voltage with respect to the positive-phase two-dimensional coordinate axis
Phase θ_pAnd the set power factor phase ψ
Phase current phase φ_pAnd calculate the phase φ of the two-phase positive-sequence current._p
The phase θ of the first phase_iTo the semiconductor switch.
Of the input current command for specifying the current to be input to the switch group
Phase θ of positive phase component of phase₁And generates the two-phase positive-sequence voltage
The absolute value is multiplied by a predetermined constant to calculate the first value of the input current command.
Of the positive phase component of the phase_pAnd E_psin θ₁Enter the above
Positive phase current command I * of the first phase of current command_p1And E_psin
[θ₁-(2π / 3)] and E_psin [θ₁+ (2π / 3)]
Positive phase current command I * for phase 2_p2, The positive-phase current command I * for the third phase
_p3And the input current control unit further performs an axis coordinate inverse transformation.
The negative-phase secondary of the two-phase negative-phase voltage extracted by the processing
Phase θ with respect to the original coordinate axis_nIn addition, the set power factor phase
ψ is added and the phase φ of the two-phase reverse-phase current_nIs calculated, and
Phase φ of two-phase reverse-phase current_nThe phase θ of the first phase_iAdd
And specify a current to be input to the semiconductor switch group.
Phase θ of the negative phase component of the first phase of the input current command_TwoGenerate a
Multiplying the absolute value of the two-phase negative-sequence voltage by a predetermined constant
The amplitude E of the negative phase component of the input current command_nAnd E_n sin θ
_TwoIs a negative phase current command I * of the first phase of the input current command._n1When
Then E_nsin [θ_Two+ (2π / 3)] and E_nsin [θ_Two-(2π / 3)]
The negative phase current command I * of the second phase respectively_n2, The positive phase of the third phase
Current command I *_n3And the input current control unit further comprises:
Positive-phase current command I * for the first phase, second phase, and third phase _p1, I
*_p2, I *_p3From the first phase, the second phase, and the third phase
Flow command I *_n1, I *_n2, I *_n3To the first phase,
Current command I * for the second and third phases₁, I *_Two, I * _ThreeGenerate a
The current reference calculation unit includes a first phase, a second phase, and a third phase.
Current command I *₁, I *_Two, I *_ThreeOf which the current command value is the largest
Phase, the current command value is the intermediate value phase, the current command value is the minimum phase,
And the phase combination with the largest absolute value of the current command value.
The phase of one cycle of force exchange is divided into 12 phase regions, and each phase
Given the current command values of
Of which is the minimum current command for the intermediate current command value Imid
Calculate the ratio Iref of the value Imin, and calculate the
Of the current command values, the phase with the largest current command value, the current command value
Is the intermediate value phase, the phase with the smallest current command value,
Phase range of current command corresponding to phase combination with maximum value
And outputs the same to the input voltage determination unit. The input voltage determination unit determines
Enter the phase domain division, and enter the
In the phase domain of the input three-phase AC voltage corresponding to the phase domain
The phase with the largest AC voltage value, the phase with the intermediate AC voltage value,
The phase with the smallest AC voltage value, and the phase with the largest AC voltage value
To correspond to the determined current command phase region.
AC voltage set in the phase region of the input three-phase voltage
The phase with the largest value, the phase with the AC voltage
The minimum phase and the phase with the largest absolute value of the AC voltage value are detected.
Maximum value Emax, intermediate value Emid, minimum value of the output AC voltage value
Emin, assigned the largest absolute value Ebase, assigned
Calculate ΔEmax and ΔEmid from voltage value
PWM cycloconverter device. 9. The positive-phase component detecting section converts a two-phase AC voltage into a positive-phase signal that rotates in the same phase as the first phase of the three-phase AC voltage.
An axis coordinate positive conversion unit that performs an axis coordinate positive conversion process for extracting a two-phase positive phase voltage with reference to the two-dimensional coordinate axis; and a high-frequency noise component from the two-phase positive phase voltage component output from the axis coordinate positive conversion unit. A first-order lag filter to be removed, an amplitude detector for detecting the absolute value of the two-phase positive-sequence voltage, and a phase detector for detecting the phase of the two-phase positive-sequence voltage with respect to the positive-phase two-dimensional coordinate axis; The phase coordinate detecting unit extracts a two-phase negative-phase voltage from the two-phase AC voltage with reference to an anti-phase two-dimensional coordinate axis rotating in an opposite phase with respect to the first phase of the three-phase AC voltage. An axis coordinate inverse transform unit for performing processing, a first-order lag filter for removing high-frequency noise components from the two-phase negative-phase voltage components output from the axis coordinate inverse transform unit, and a second-order lag filter output from the first-order lag filter An amplitude detector for detecting the absolute value of the phase-reverse-phase voltage,
The PWM cycloconverter device according to claim 8, further comprising a phase detector that detects a phase of the two-phase opposite-phase voltage with respect to the opposite-phase two-dimensional coordinate axis. 10. A power circuit for transmitting power of a three-phase power supply to a load through a semiconductor switch group including a plurality of bidirectional semiconductor switches, a three-phase voltage detection unit for detecting a power supply voltage,
A phase detection unit that detects the phase θ _i of the first phase of the power supply voltage;
Based on the three-phase AC voltage detected by the three-phase voltage detector and the phase detected by the phase detector, the input 3
The ratio of the phase current value of the phase having the smallest current value to the phase current value of the phase having the intermediate value of the phase current, that is, a current control unit that generates a current distribution ratio, is detected by the three-phase voltage detection unit. An input voltage determining unit that receives the input three-phase AC voltage, determines the magnitude of the three-phase AC voltage, and generates ΔEmax and ΔEmid.
A control unit having a PWM voltage control unit that receives the current distribution ratio and ΔEmax and ΔEmid to generate a PWM switching control signal; and a driving unit that switches the semiconductor switch group in response to a PWM switching control signal. In the three-phase PWM cycloconverter device, the current controller has an input current controller and a current reference calculator, and the input current controller multiplies an input three-phase voltage by a constant to obtain a three-phase AC current. From the three-phase alternating current,
A phase input current command is extracted, and the three-phase AC current is subtracted from twice the positive-phase three-phase input current command to generate a three-phase input current command. , The second phase, and the third phase current command I * ₁ , I * ₂ , I * ₃ , the phase with the largest current command value, the phase with the middle current command value, and the smallest current command value phase,
For each combination of phases in which the absolute value of the current command value is the largest, the phase of one cycle of the input AC is divided into 12 phase regions, and when the current command value of each phase is given, the Among them, the ratio Iref of the minimum current command value Imin to the current command value Imid of the intermediate value is calculated, and, among the given current command values of the respective phases, the phase in which the current command value is the largest, the current command value is The phase of the intermediate value, the phase with the smallest current command value, the phase region of the current command corresponding to the combination of the phase with the largest absolute value of the current command value are determined and output to the input voltage determination unit, and the input voltage determination is performed. The unit receives twelve phase region divisions from the current reference calculation unit, and in each phase region of the input three-phase AC voltage corresponding to the divided input AC phase region, the phase having the largest AC voltage value; A phase whose AC voltage value is an intermediate value,
The phase in which the AC voltage value is the minimum and the phase in which the absolute value of the AC voltage value is the maximum are set in advance, and the phase is set in the phase region of the input three-phase voltage corresponding to the phase region of the determined current command. For the phase with the highest voltage value, the phase with the intermediate AC voltage value, the phase with the minimum AC voltage value, and the phase with the maximum AC voltage value, the maximum value Emax of the detected AC voltage value, the intermediate value The value Emid,
A PWM cycloconverter, wherein a minimum value Emin and a maximum absolute value Ebase are assigned, and ΔEmax and ΔEmid are calculated from the assigned voltage values. 11. An input current control unit comprising a first, a second, and a third
, A first, second, and third 90-degree phase conversion filter, and first and second subtractors, fourth, fifth, sixth,
A seventh multiplier, a third and a fourth subtractor, an eighth and a ninth multiplier, a fifth and a sixth subtractor, and a multiply-adder; a first, a second and a third multiplication The multiplying unit generates an AC current by multiplying the instantaneous value of the AC voltage of the first phase, the second phase, and the third phase by a predetermined constant, respectively, and generates the first, second, and third 90 degrees. The phase conversion filter converts the phase of the AC current of the first phase, the second phase, and the third phase output from the first, second, and third multipliers by 90 °, respectively, and The subtractor subtracts the output of the second 90-degree phase conversion filter from the output of the first 90-degree phase conversion filter.
The output of the second 90-degree phase conversion filter is subtracted from the output of the 90-degree phase conversion filter, and the fifth and sixth multipliers add [2 · 3 ^1] to the outputs of the first and second subtractors, respectively. ^{/ 2} ] multiplied by ^-1 and output.
The fourth and seventh multipliers multiply the outputs of the first and third multipliers by １ ／, respectively, and output the result. The third subtractor calculates the sixth output from the output of the fourth multiplier. The fourth subtractor subtracts the output of the fifth multiplier from the output of the seventh multiplier, and the eighth and ninth multipliers respectively subtract the output of the fifth multiplier from the output of the seventh multiplier. The output of the subtracter of 4 is multiplied by 2 and the result of the multiplication is output.
The sixth subtractor subtracts the current value of the first phase and the current value of the third phase from the outputs of the eighth and ninth multipliers, respectively, and outputs the result as the current command of the first phase, respectively. , The current command of the third phase, and the multiplication / addition unit outputs the fifth and sixth current commands.
2. The output of the subtractor of claim 1 is multiplied by -1, the multiplication result is added, and the result is output as a second-phase current command I * _S.
0. The PWM cycloconverter device according to 0.