JP2917838B2 - Current command value limiting device and limiting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for limiting a current command value of a converter having a current control system.

[0002]

2. Description of the Related Art FIG. 31 is a collection of lectures, for example, of the National Conference of the Industrial Applications Division of the Institute of Electrical Engineers of Japan (August 23-25, Fukuoka)
P. FIGS. 517 to 522 are block connection diagrams in which the control circuit of the converter having the conventional current control loop shown in “Voltage distortion control method of CVCF” is rewritten in the same form as that of the present invention. The phase alternating signal lines are indicated by a single line with three oblique lines added. The three-phase AC values are V _A , V _C ,
Two-phase values in a dq coordinate system, which is a rotating coordinate system, are represented as V _2A and V _2C .

In FIG. 31, 1 is a converter main circuit, 2 and 3 are reactors and capacitors constituting an AC filter,
Is a DC power supply, 5 is a load, 202, 203, and 204 are converters for converting three-phase AC values to values in a dq coordinate system, and 201 is a converter for converting values in a dq coordinate system to three-phase AC values. Vessel, 314 is dq
A phase generator for converting to a coordinate system, 501 is a drive circuit for a converter main circuit, and 306 and 307 are q- and d-axis coordinate systems obtained by converting an AC three-phase sine wave reference voltage to a dq coordinate system, respectively. Voltage command value generation circuit that outputs voltage command value, 304, 30
5 is a voltage controlled amplifier for the q and d axes of the dq coordinate system, respectively.
(Voltage Controler).

[0004] 312 and 313 are adders / subtracters 703 and 704, respectively.
Current limiters for limiting the output of the converter as a current command to within the allowable current value of the converter, 302 and 303 are current control amplifiers (Current Controllers) of the q and d axes, 322, 323 and 324, respectively.
Is a control system for decoupling, and 320 and 321 are primary steps configured to remove the influence of the output current in the decoupling system. Numeral 301 denotes a PWM modulation circuit which comprises, for example, comparison circuits 301a to 301c and carrier wave generation circuits 301d to 301f as shown in FIG. 701 to 712 are adder / subtracters, 801 and 802 are current detectors, and 803 is a voltage detector.

Next, the operation of FIG. 31 will be described. A sinusoidal output voltage corresponding to the output of the PWM modulation circuit 301 is obtained between the terminals of the capacitor 3. On the other hand, the outputs _V2Cq ^* , _V2 of the voltage command value generation circuits 306, 307 in the dq coordinate system
_2Cd ^* and the output voltage V _c detected by the voltage detector 803
_Is the difference between the values V _2Cq and V _{2Cd in} the dq coordinate system.
The outputs are obtained by 705 and 706 and controlled by voltage control amplifiers 304 and 305 so that the voltage deviations become zero, respectively, and this output and the outputs of adder / subtracters 711 and 712 are input to adder / subtractors 703 and 704.

The adders / subtracters 711 and 712 receive the load current I _{2L as} a feedforward signal and the output of a control system 324 for decoupling as inputs. Current limiter 312,
313, q current command value, which is the output of the adder-subtracter 703, 704, independently of each d-axis component is limited to less than the allowable current value, and outputs the value current command I _2aq ^*, as I _2Ad ^* I have. Here, a specific description will be given using equations. u-v
-The current on the w coordinate is displayed as I, and the current on the dq coordinate is displayed as I ₂ . Here, ωt is usually a phase synchronized with I. The matrix C in the expression (3) is a matrix for converting a vector on the UVW coordinate into the dq coordinate, and the relationship in the expression (4) holds. In the case where the current I is given in the equation (4) as in the equation (5), the value obtained on the dq coordinates is shown in the equation (6). (However, the effective value of the current I is k.)

[0007]

(Equation 1)

As described above, the “three-phase alternating current value not including harmonics” (I _d , I _q ) converted on the dq coordinates is accompanied by a change in γ with a radius of √3K (K is an effective value). You can see that it moves on the circle. Then, assuming that the current I is an allowable current value determined from the overcurrent protection level of the electric valve of the converter, the current I ₂ indicates an allowable current value on dq coordinates,
That is, when the current command value on the dq coordinates exists outside the circle, the current command value is limited to the allowable current value or less by converting the current command value to the inside including the circle. However, in the case of the control block diagram in FIG. 31, the q and d-axis components of the current command value are independently limited so as to be within ± √3 / 2K. That is, the current command value is converted into a square inscribed in the circle.

[0009] and the current command value thus converted, the converter output current I _A which is detected by the current detector 801 d-q
The value I _2aq, adder-subtractor 701 the deviation I _2Ad in the coordinate system, 70
The current control amplifiers 302 and 303 control the current deviation to be zero, and the PWM modulation circuit 301 controls the switching of the converter 1. Here, description of the non-interference control elements 322, 323, 324 and the accompanying temporary delay elements 320, 321 will be omitted.

FIG. 33 shows, for example, IPEC Industry Applications
Society Annual Meeting 1990 (April 2-6, Shinjuku,
Tokyo, Japan), pp. 107-114, `` PARALLEL PRO
CESSING INVERTER SYSTEM '' is a block connection diagram in which the current limiter having the conventional current control loop shown in `` CESSING INVERTER SYSTEM '' has been rewritten in the same form as the present invention, in which a three-phase AC signal line and a triangular line are added. This is indicated by a solid line. Also, three-phase alternating current value, V _A, V _C, which is a rotating coordinate system d-
The values of the q coordinate system are shown as V _2A and V _2C .

In FIG. 33, 1 is a converter main circuit, 2 and 3 are reactors and capacitors constituting an AC filter,
Is a DC power supply, 5 is a load, 202, 203, and 204 are converters for converting three-phase AC values to values in a dq coordinate system, and 201 is a converter for converting values in a dq coordinate system to three-phase AC values. Vessel, 314 is dq
A phase generator for converting to a coordinate system, 501 is a drive circuit for a converter main circuit, and 306 and 307 are q- and d-axis voltages obtained by converting an AC three-phase sine wave reference voltage to a dq coordinate system, respectively. It is a voltage command value generation circuit that outputs a command value. 304
, 305 are q- and d-axis voltage controlled amplifiers (Voltag
e Controler), 310 and 311 are adders / subtracters 703 and 7 respectively.
04 is a current limiter that limits the output to a current command within the allowable current value of the converter, 302 and 303 are q and d axis current control amplifiers, respectively, and 301 is PWM.
In the modulation circuit, for example, as shown in FIG.
1c and carrier generation circuits 301d to 301f. 701 to 706 are adder / subtracters, 801 and 802 are current detectors, 8
03 is a voltage detector.

Next, the operation of FIG. 33 will be described. A sinusoidal output voltage corresponding to the output of the PWM modulation circuit 301 is obtained between the terminals of the capacitor 3. On the other hand, the outputs _V2Cq ^* , _V2 of the voltage command value generation circuits 306, 307 in the dq coordinate system
_2Cd ^* and the output voltage V _C detected by the voltage detector 803
_Is the difference between the values V _2Cq and V _{2Cd in} the dq coordinate system.
705 and 706, and controlled by voltage control amplifiers 304 and 305 so that the voltage deviation becomes zero. The output and the load current I _2L as a feedforward signal are _added and subtracted by an adder / subtractor 703.
, 704. The current limiters 310 and 311 are:
Subtracter 703, 704 the output of, d-q was converted onto the coordinate limits below the allowable current value of the "three-phase alternating current value free of harmonics", the current command value and the value I _2Aq ^*, I _2Ad ^* Is output as In this case, since the circle shown by the equation (6) is the allowable current value on the dq coordinate, the current command value is converted into the inside including the circle so that the current command becomes equal to or less than the allowable current value. Limited.

[0013] In addition, as shown in FIG. 34, the current command value (d1, q1) is considered as a vector, the angle α is not changed, and the current command value (d1, q1) is moved in the direction of the origin. , the current command value is limited to the value (I _2Ad ^*, I _2Aq
^* ). Then, a current command value through the above operation, the value I _2Ad in d-q coordinate system of the converter output current I _A which is detected by the current detector 801, a subtracter 701, 702 a deviation between I _2aq The control is performed by current control amplifiers 302 and 303 so that the current deviation becomes zero, and the switching of the converter 1 is controlled by a PWM modulation circuit 301 which receives the control signal as an input.

[0014]

The conventional method for limiting the command value is configured as described above. In both of the conventional examples, "including harmonics converted on dq coordinates is included." The command value was limited to "no allowable value" or less. But,
In practice, the tolerances include harmonics, so this will not limit at the expected level, and dq
It is necessary to limit the command value to not more than the "allowable value including harmonics" converted on the coordinates.

Here, the "allowable value determined from the overcurrent protection level of the electric valve of the converter" will be described with reference to FIG. As shown in FIG. 35, the inductance L of the wiring
And the output capacity C of the electric valve, the current flowing through L immediately before the switch is turned off is defined as I. At the time of turn-off, the energy stored in L (1/2 LI)
² ) moves to C, and a voltage of √ (L / C) · I is applied to the switch. It is necessary to set L, C, and I to appropriate values so that this voltage does not exceed the rated voltage of the switch. The current value set in this manner is referred to as an "overcurrent protection level of the electric valve". The “permissible value” described here is a value set to a value lower than the above-mentioned overcurrent protection level.

Next, the allowable value of the converter including the harmonic is d.
-Find the range indicated on the q coordinate. Assuming that the three-phase AC value including harmonics is (U, V, W) and the value on the dq coordinates is (Q, D), using the transformation matrix C, the relational expressions are (7) to (7). Equation (9) is obtained. That is, (Q, D) can express ωt, U, V, W, as variables.
Then, assuming that ωt is constant, the trajectory of (D, Q) under the condition shown in equation (10) is obtained as shown in equations (11) and (12). (However, MAX indicates the permissible value of the converter.) Further, any V satisfying the expression (10) is defined as V1 and V2,
Substituting into equations (11) and (12) respectively gives (1)
Equations 3) and (14) are obtained. (However, the subscript x is 1
Or Wx = − (MAX + Vx). )

[0017]

(Equation 2)

Here, if a straight line connecting (D1, Q1) and (D2, Q2) is expressed by an equation using variables (X, Y), the equation becomes as follows, and arbitrary V1 and V2 terms are deleted. Is obtained. This means that when U and ωt are fixed, V and W are (1
(D, Q) when it is changed in the range of the expression (0) indicates that it moves on the straight line indicated by the expression. Similarly, ωt
Is constant and U is fixed to -MAX, and V and W are changed within the range of the condition (15), an equation is obtained. Similarly, when ωt is fixed, V is fixed to MAX, and U and W are changed within the range of the condition (16), an equation is obtained. Similarly, ωt is fixed and V is fixed at −MAX (1
When U and W are changed within the range of the condition of 7), an equation is obtained.

[0019]

(Equation 3)

When ωt is constant and W is fixed to MAX,
When U and V are changed within the range of Expression (18), Expression () is
When W is fixed to -MAX and U and V are changed within the range of Expression (19), Expression () is obtained.

[0021]

(Equation 4)

As described above, when one of U, V, and W is fixed and the other two are changed within a certain range, it can be obtained by using a transformation matrix C on the dq axes ( D,
It can be seen that Q) moves on a certain straight line.

Next, it is shown that the twelve end points of the above-mentioned six straight lines (Eq. ~; Hereinafter, the straight lines... Indicate the formulas...) Are in one-to-one correspondence. . First, it is known that the point (D, Q) on the equation representing the straight line can be represented by the equations (8) and (9) under the condition of the equation (7). Think about differentiating. In the formula,

[0024]

(Equation 5)

When ωt is constant, the sign of the value obtained by differentiating D with V (dD / dV) is constant irrespective of the value of V. That is, when the value of V is increasing, D is also That is, when V is the minimum value and the maximum value, (D, Q) exists at the end point of the straight line. The values of (D, Q) when V = −MAX are substituted into the equations (8) and (9) are (D ₁₁ , Q ₁₁ ), and the values when V = 0 are substituted are (D ₁₂ , Q ₁₂ ), Equation (21) is obtained.

[0026]

(Equation 6)

Considering the same, when the end point of the equation is V = 0 (D
₂₁ , Q ₂₁ ) and V = MAX (D ₂₂ , Q ₂₂ )

[0028]

(Equation 7)

,,, Are similarly given by (23),
Equations (24), (25) and (26) can be used.

[0030]

(Equation 8)

[0031]

(Equation 9)

It can be seen that the end points of the six straight lines are in one-to-one correspondence. Next, the straight line
Indicate that they rotate one-to-one clockwise around the center of the origin, indicating that they match one-to-one. Now, the straight line of Y = A.X + B is
When rotated δ around the origin, It is known that this can be expressed as

[0033]

(Equation 10)

## EQU1 ## This equation is consistent with a straight line. Similarly, if you rotate each straight line 60 degrees clockwise around the origin, you can see that the straight line is a straight line, the straight line is a straight line, the straight line is a straight line, the straight line is a straight line, the straight line is a straight line, and the straight line is a straight line .

Next, consider the case where ωt of the straight line is replaced by ωt + π / 3. Adapting to a straight line,

[0036]

[Equation 11]

Thus, it can be seen that a straight line is shown. Similarly, when ωt of each straight line is replaced with ωt + π / 3,
It can be seen that a straight line is a straight line, a straight line is a straight line, a straight line is a straight line, a straight line is a straight line, a straight line is a straight line, and a straight line is a straight line.

From the above, when the phase ωt is constant and U,
The three-phase AC value including harmonics V and W is U + V + W = 0
Is satisfied, and when the value changes between the allowable values (± MAX), it is found that the range of the allowable values of the converter converted into the dq coordinate system using the conversion matrix C shows a regular hexagon. In particular, if any one of U, V and W has an allowable value, d-
It can be seen that the q-coordinate is on the side of a regular hexagon. That is, when a value exceeding the allowable value of the converter is input to the current limiter, the value exists on the dq coordinates at a position outside the inside of the regular hexagon and the range on the side thereof.
In addition, it has been found that the permissible value (regular hexagon) on the dq coordinates rotates clockwise with the passage of time (increase in ωt). Then, as shown in FIG. 36, this regular hexagon is ωt
When = 0, the intersection with the q-axis is ± √3 / 2 MAX, which is a circle showing the range of allowable values without harmonics in the dq coordinate system (radius = √3K: K is an allowable value). Value effective value)
If it is outside (MAX = √2K) and the d and q axis components of the command value are independently limited, the allowable value is d−q
It can be seen that the coordinates indicate the inner square in contact with the circle.

FIG. 37 (a) shows a command value (including a fifth harmonic and a seventh harmonic) for the current limiters of the conventional example (the allowable value is a square or a circle) and the embodiment (the allowable value is a regular hexagon). A half cycle of the output waveform (u-phase) of the current limiter when equation 29 is given is plotted in real time, and FIG. 37 (b) shows the inverter output voltage. FIG. 38 is a graph in which the command value (29) is plotted on dq coordinates. I _U = SIN (ωT) -0.6 ・ SIN (5ωt) -0.2 ・ SIN (7ωT) I _V = SIN (ωT- 2π / 3) -0.6 ・ SIN (5ωt-2π / 3) -0.2 2π / 3) I _W = SIN (ωT + 2π / 3) -0.6 ・ SIN (5ωt + 2π / 3) -0.2 ・ SIN (7ωT + 2π / 3) (29)

According to FIG. 37, when the allowable value is a regular hexagon, the input waveform is the same (not limited), and when the allowable value is a circle and a square, the input waveform is limited. This is because, as shown in FIG. 38, the command value (moving from point S to point S over time) may exist inside a regular hexagon and outside a circle and a square. As described above, in the conventional example (the allowable value is a square or a circle), even if the command value is equal to or less than the allowable value that can be commanded to the converter (that is, it is not necessary to limit), it is extremely limited. There is a problem that was done.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a first object is to derive that an allowable value of an electric valve of a converter becomes a regular hexagon on dq coordinates. It is an object of the present invention to provide a control method for limiting a command value of a converter output current to a value equal to or less than the above allowable value. Further, the second object is the first object.
Among the objects of (1), an algorithm (flow chart) that minimizes the program execution time is obtained.

Further, a third object is to obtain an algorithm (flowchart) for limiting only the q-axis component while keeping the d-axis component of the command value on the dq coordinates among the first objects. Things. A fourth object is to obtain an algorithm (flowchart) for limiting only the d-axis component while keeping the q-axis component of the command value on the dq coordinate among the first objects. .

[0043]

According to a method of limiting a current command value according to the present invention, a command value given to a current control system is set to d
A command value of the -q coordinate, is obtained by a value obtained by limiting within a range indicated by the tolerance on the d-q coordinates, calculated in advance.

As the allowable values on the dq coordinate, at least one phase is an allowable value on the uvw coordinate, and the other phase is a three-phase AC value within the allowable value, d- The value converted on the q coordinate is obtained.

As a command value given to the current control system, d
-The command value on the q-coordinate is changed to the allowable value on the uvw-coordinate and d.
-Indication of allowable value on dq coordinate obtained from phase of q coordinate
The value is limited within the range.

Also, the command value and the allowable value on the uvw coordinate
And a value that limits the command value on the dq coordinates is obtained by comparison with.

[0047] Further, the command value on the d-q coordinates and the allowable value
Is obtained by limiting the d-axis component and the q-axis component of the command value on the dq coordinates at the same ratio.

[0048] Further, the allowable value and the command value on the d-q coordinates
By comparison , the d-axis component and the q-axis component of the command value on the dq coordinates are limited at different rates.

Further, the known permissible value on the dq coordinate is rotated about the origin of the dq coordinate, and the command value on the dq coordinate is determined by the command value on the dq coordinate and the permissible value. The d-axis component and the q-axis component are restricted at the same ratio.

The allowable value on the dq coordinate is rotated about the origin on the dq coordinate, and the d-axis of the command value on the dq coordinate is obtained by the command value on the dq coordinate and the allowable value. The component and the q-axis component are restricted at the same ratio.

Further, a value which limits the d-axis component and the q-axis component of the command value on the dq coordinate by the same ratio by comparing the command value on the uvw coordinate with the allowable value is obtained. It is.

[0052] Further, the allowable value and the command value on the d-q coordinates
By comparison , the d-axis component of the command value on the dq coordinates is constant and only the q-axis component is limited.

[0053] In addition, a command value of the d-q coordinates and tolerance
By comparison , the q-axis component of the command value on the dq coordinates is constant and only the d-axis component is limited. Further, an apparatus for obtaining the above means is configured.

[0054]

In the method for limiting the current command value obtained as described above, the command value given to the current control system is uv
-D obtained from the allowable value on the w coordinate and the phase of the dq coordinate
Since the value in which the command value on the dq coordinate is limited within the range indicated by the allowable value on the -q coordinate, the allowable value (regular hexagon) is wider than in the conventional example, and the current that can be passed to the converter Without unnecessarily restricting the command value to an appropriate allowable value or less.

As the allowable values on the dq coordinates, at least one phase is an allowable value on the uvw coordinate, and the other phase is a three-phase AC value within the allowable value described above. Since the value converted on the q coordinate is obtained, the allowable value (regular hexagon) is wider than in the conventional example, and the command value is equal to or less than the appropriate allowable value without unnecessarily restricting the current that can flow through the converter. Work to limit to.

Further, since the value for limiting the command value on the dq coordinate is obtained from the command value on the dq coordinate and the allowable value, the ratio of limiting the effective component and the invalid component of the command value is d. Movement of the command value on the -q coordinate makes it easy to visually understand the limiting ratio.

Further, since the value for limiting the command value on the dq coordinate is obtained from the command value on the uvw coordinate and the allowable value, the calculation for obtaining the limiting value is simplified, and the current command value is reduced. The processing speed is increased because it works to shorten the program of the restriction method.

Further, a value for limiting the d-axis component and the q-axis component of the command value on the dq coordinate at the same ratio is obtained from the command value on the dq coordinate and the allowable value. Since the ratio of limiting the effective component and the invalid component can be determined by moving the command value on the dq coordinates toward the origin, the visual understanding of the limiting ratio is facilitated.

Also, since a value for limiting the d-axis component and the q-axis component of the command value on the dq coordinate at different rates is obtained from the command value on the dq coordinate and the allowable value, Since the ratio of limiting the effective component and the invalid component can be determined by the movement of the command value on the dq coordinates, the visual understanding of the limiting ratio is facilitated.

Further, the known permissible value on the dq coordinate is rotated about the origin of the dq coordinate, and the command value on the dq coordinate is determined by the command value on the dq coordinate and the permissible value. To determine the value that limits the d-axis component and the q-axis component at the same rate, the ratio is limited because the ratio of limiting the effective component and the invalid component of the command value can be found by moving the command value on the dq coordinates toward the origin. The visual understanding of the ratio to be performed becomes easy.

The command value on the dq coordinate is rotated about the origin on the dq coordinate, and the command value on the dq coordinate and the allowable value are used to rotate the command value on the dq coordinate. To find the value that limits the component and the q-axis component at the same rate, the rate at which the rate at which the effective and invalid components of the command value are limited can be determined by moving the command value on the dq coordinates toward the origin. And the processing speed is increased because it works to shorten the program of the current command value limiting method. .

Further, a value for limiting the d-axis component and the q-axis component of the command value on the dq coordinate at the same ratio is obtained from the command value on the uvw coordinate and the allowable value. Is simplified, and the program for the current command value limiting method is shortened, so that the processing speed is increased.

Further, since the d-axis component of the command value on the dq coordinate is determined to be constant and only the q-axis component is limited by the command value on the dq coordinate and the allowable value, the effective current of the command value is obtained. It works to limit the reactive current while keeping the constant.

Further, the q-axis component of the command value on the dq coordinate is determined by the command value on the dq coordinate and the allowable value to limit the d-axis component only. It works to limit the effective current while keeping the constant.

[0065]

【Example】

Embodiment 1 FIG. FIG. 1 shows an embodiment of the present invention. In the figure, the signal line of the three-phase AC value is indicated by a single line to which three oblique lines are added. Further, the PWM modulation circuit 301D and the current limiter 30
All the components other than 8 correspond to the same reference numerals in the conventional example, and the description thereof will be omitted. If necessary in the description, the value on the dq coordinate is “command value [d], allowable value [d]”, and the value on the uvw coordinate is “command value [u], allowable value [u]. ]].

The current limiter 308 is a current command value limiting means that receives the command value [d] of the converter output current, which is the output of the adders 703 and 704, as an input. Control means for limiting the command value to an allowable value [u] or less. Also, the PWM modulation circuit 301D
Is a modulation circuit which receives a digital value of three-phase AC as an input. The above tolerance [d] is a regular hexagon that rotates clockwise around the origin on a dq coordinate basis, and the length of one side of the hexagon is √2MAX (MAX is uv−v−2). w
(Coordinate allowable value).

FIG. 2 is a circuit diagram showing the electrical connection of FIG. In the figure, the signal line of the three-phase AC value is indicated by a single line to which three oblique lines are added. 1,2,3,4,5,501
, 801, 802, and 802 respectively correspond to those having the same reference numerals in FIG. 1, and description thereof will be omitted. Reference numeral 1000 denotes a microprocessor, which includes a CPU 1000d, a memory 1000b, an input circuit 1000a, and an output circuit 1000c. Reference numeral 502 denotes an A / D converter for converting an analog value to a digital value. Reference numeral 301D denotes a PWM modulation circuit having an oscillator 301Da, an up / down counter 301Db, and a digital comparator 301Dc.

Next, the operation of the A / D converter 502, the microprocessor 1000, and the PWM modulation circuit 301D of FIG. 2 will be described. The digital value of the load voltage, load current, and converter output current converted by the A / D converter 502 is received by the input circuit 1000a of the microprocessor 1000, and is stored in the memory 1000.
b The CPU 1000d performs an operation in accordance with the processing of the above program, and the obtained value is output by the output circuit 1000c to the PWM modulation circuit 30.
Output to 1D digital comparator 301Dc.

The digital comparator 301Dc compares the value of the counter generated by the oscillator 301Da and the up / down counter 301Db with the magnitude of the command value of the converter output current output from the output circuit 1000c, and finds that the command value is larger. A high ("1") signal is output if the signal is low, and a low ("0") signal is output if the signal is small, as many as the number of electric valves in the converter main circuit.

As described above, FIG. 2 is a block diagram of FIG. 1 in which processing is performed by the microprocessor 1000 (a control block diagram between three-phase / two-phase conversion and two-phase / three-phase conversion). Is replaced by a microprocessor 1000 to show the internal configuration of the PWM modulation circuit 301D of FIG.

Next, the operation of the current limiter 308 will be described with reference to FIGS. FIG. 3 is a flowchart showing a current command value limiting program stored in the memory of the microprocessor in FIG. 2, FIG. 4 is an operation explanatory diagram relating to a method of comparing the command value [d] with the allowable value [d], and FIG. FIG. 9 is a diagram for explaining a comparison condition between a value and an allowable value.

First, when a command value of the converter output current is input to the current command value limiting means (ST1 in FIG. 3), the position of this command value (point A in FIG. 4) on the dq coordinates is determined. To find it, the equation of ST2 is calculated (α in ST2 is the same as α in FIG. 4). Next, in ST3, ωt (the angle at which the regular hexagon which is the allowable value is rotated clockwise) is loaded, and in ST4, α and ω
t is added, and the value (α ′) is divided by π / 3 to calculate an integer part of a quotient as N (INT in the figure gives an integer part).

A straight line L2 in FIG. 4 (one side of a regular hexagon indicating an allowable value) is rotated around the origin, and a straight line L _{F in} FIG.
When the equation representing the side is obtained, if the straight line L _F is parallel to the q-axis, the rotated straight line L 2 cannot be represented by the equation, and such a condition is determined in ST5. And
In ST8, in L _F is determined magnitude relation of command value and the allowable value when is parallel to the q-axis, ST9 if I exceeds the allowable value,
Command values are limited.

[0074] L when _F is not parallel to the q-axis, in ST6, obtains an expression representing a straight line L _F is rotated by N · π / 3-ωt counterclockwise to the origin around the straight line L2 in FIG. 4, the L _F
The d-axis component of the command value (point A in FIG. 4) (I in FIG. 4)
_2Ad ^* ) is substituted for the q-axis component of the point C and Y is calculated. Then, as a necessary condition for comparing the magnitude of Y with I _2Aq ^* , the remainder obtained by dividing the rotation angle of L2 by 2π is calculated in ST7. As shown in FIGS. 5 (a) and 5 (b), even when the command value (point A) is outside the regular hexagon, when the rotation angle of L2 is π / 2 and 3π / 2, for hierarchical relationship a and the straight line L _F is changed, the operation is necessary.

[0075] and then make a determination of whether or not the command value is equal to or less than the allowable value in ST10~ST15, when it is within the allowable value, which is an input command value _{^{(I 2Ad *, I 2Aq *}} ) is output as it is, If it exceeds the allowable value, the operation of ST16 is performed to limit the command value to the allowable value or less. (The operation in ST16 finds point B in FIG. 4.)

As described above, according to the processing of the above flow chart, a wider allowable value [d] (regular hexagon) than in the conventional example can be taken, so that the current that can be passed through the converter is unnecessarily limited. Thus, the command value can be limited to a required allowable value or less, so that the electric valve of the converter can be used efficiently.

Embodiment 2 FIG. FIG. 6 shows another embodiment of the present invention. In the figure, the signal line of the three-phase AC value is indicated by a single line to which three oblique lines are added. In the figure, all the components other than the current limiter 309 correspond to those of the above-described first embodiment, and the description thereof is omitted. Current limiter 30
Reference numeral 9 denotes a current command value limiter which receives a command value [d] of the converter output current, which is an output of the adders 703 and 704, as an input. u] Hereinafter, control means for limiting the command value will be described.

The permissible value [d] is a regular hexagon that rotates clockwise around the origin on the dq coordinates every moment, and the length of one side is √2MAX (MAX is u −
vw coordinate). In the first embodiment, the control unit configured to rotate the allowable value [d] determined in advance around the origin and to compare the rotation with the command value [d] is configured in the second embodiment. Output current command value [d]
Is rotated around the origin and is compared with a previously obtained allowable value [d]. FIG.
The electrical connection of the memory of the microprocessor 1000 of FIG.
The program on 1000b is different from that of the first embodiment, and can be configured in the same manner as FIG. 2 of the first embodiment.

Next, the operation of the current limiter 309 will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 4 is an operation explanatory diagram relating to a method of comparing a command value and an allowable value on dq coordinates, and FIG. 7 is a flowchart showing a current command value limiting program stored in the memory 1000b of the microprocessor 1000 in FIG.

Steps ST1 to ST4 in FIG. 7 are the same as those in FIG. 3, and a description thereof will be omitted. Since the allowable value [d] is a regular hexagon that rotates clockwise clockwise on the coordinates, the positional relationship between the regular hexagon and the command value [d] (whether the command value exists inside the regular hexagon). ST17
Then, the command value [d] is rotated clockwise around the origin by N · π / 3−ωt, and the d-axis component ( _Id2 in FIG. 4) of the obtained point (point C in FIG. 4) is shown in FIG. by substituting the straight line L1 calculates the q-axis component of the point E as Y in (ST18), and compares the magnitude of the Y and I _q2 (ST19).

If _Iq2 is larger, the command value [d] (point A in FIG. 4) exceeds the permissible value, so that only the magnitude of the vector OA (command value) is changed without changing the direction. In order to limit (the vector OA in FIG. 4 is converted to the vector OB), one side of the regular hexagon (allowable value [d] when ωt of the conversion matrix C is ωt = 0) previously determined in ST20 (see FIG. 4 and a point OC in FIG. 4 (point D in FIG. 4), and this point is rotated counterclockwise by N · π / 3−ωt in ST21 to obtain the limited command value [d] ( FIG.
Of point B). Next, the program execution time when it is assumed that the flow chart of the first embodiment (FIG. 3) and the flow chart of the second embodiment (FIG. 7) are represented by a program (assembler language) and ADSP21060 (product name) is used for the microprocessor. Are shown in Table 1.

[0082]

[Table 1]

As described above, according to the flowchart of the second embodiment, in addition to the effects of the first embodiment, the program can be shortened (the program execution time is shortened), and the program creation time can be shortened. Since the program memory area can be reduced, there is an effect that a physically limited memory can be effectively used.

Embodiment 3 FIG. FIG. 8 shows another embodiment of the present invention. In the figure, a signal line of a three-phase AC value is indicated by a single line with a triangular line, and in the following description, the fundamental wave components of the current are “fundamental wave I _q , fundamental wave I _d ”, and the harmonic wave components are “ The harmonic _Iq and the harmonic _Id "are shown. 1,2,5,301D,
Reference numeral 501 corresponds to the same reference numeral in the first or second embodiment, and the description thereof is omitted. In the figure, 6 is a power system, 7 is a DC capacitor, 804 is a voltage detector, 80
5, 806 are current detectors, 807 is a harmonic detection circuit, 330 is a voltage control circuit, 205 and 206 are converters for converting three-phase AC values into values of a dq coordinate system which is a synchronous rotating coordinate system, 207 Is a converter that converts the value of the dq coordinate system, which is a synchronous rotating coordinate system, into a three-phase AC value, 713 is an adder, and 332 is "allowable current value determined by the overcurrent protection level of the electric valve of the converter." 331 is a current limiter for limiting the command value.

Next, the operation of FIG. 8 will be described. The harmonic component of the current (I _L ) supplied to the load is detected at 807,
The three-phase / two-phase converter 205 converts the data into dq coordinates to obtain load current harmonics on the dq coordinates. The q-axis component of this value is input to a current limiter 332, For the axis component, a current command value necessary to hold the DC capacitor voltage obtained by the voltage control circuit 330 is added and input to the current limiter 332.

In the first and second embodiments, the d and q-axis components of the command value [d] are limited at the same ratio by the current limiter, but the current command necessary to hold the voltage of the DC capacitor 7 is limited. If the d-axis component of the value is limited, the voltage of the DC capacitor 7 cannot be compensated. Therefore, the command value [d] of the converter is changed by changing only the q-axis component without changing the d-axis component as much as possible. It is limited to the allowable value of the electric valve.

Then, the harmonic component of the load current limited by the current limiter 332 to not more than the allowable current value of the converter and 805
Is controlled by the current control circuit 331 so that the deviation of the value of the converter output current on the dq coordinate detected by the above becomes zero, and the value on the uvw coordinate of the control signal is inputted. The PWM modulation circuit 301D controls the converter 1 to output a harmonic component of the load current.

As described above, by limiting only the q-axis component of the harmonic of the load current to the allowable value or less, the harmonic component of the load current is canceled and the DC voltage of the DC capacitor 7 is maintained.

FIG. 9 is a circuit diagram showing the electrical connection of FIG. In the figure, the signal line of the three-phase AC value is indicated by a single line to which three oblique lines are added. 1,2,5,6,7,501,80
4, 805, 806, correspond to the same reference numerals in FIG. 8, and the description thereof is omitted. 1000 is a microprocessor, CPU 1000d, memory 1000b, input circuit
1000a and an output circuit 1000c. 502 is an A / D converter for converting an analog value to a digital value, and 301D is a PW
M modulation circuit, oscillator 301Da, up / down counter
301Db and a digital comparator 301Dc.

Next, the operation of the A / D converter 502, the microprocessor 1000, and the PWM modulation circuit 301D of FIG. 9 will be described. The command value converted by the A / D converter 502 (a current command value necessary for compensating the DC voltage of the DC capacitor 7 and a harmonic component (a harmonic _Iq , a harmonic _Id ) of the load current) is micro-converted. Input circuit 1000a of processor 1000
In accordance with the processing of the program on the memory 1000b (the program is different for each embodiment), the CPU 1000d performs an operation, and the obtained value is output by the output circuit 1000c to the PWM modulation circuit 301D.
To the digital comparator 301Dc.

The digital comparator 301Dc compares the value of the counter generated by the oscillator 301Da and the up / down counter 301Db with the value of the command value of the converter output current output from the output circuit 1000c, and the command value is larger. A high ("1") signal is output if the signal is low, and a low ("0") signal is output if the signal is small, as many as the number of electric valves in the converter main circuit. As described above, FIG. 9 shows a part of the block diagram of FIG. 8 where processing is performed by the microprocessor 1000 (a control block diagram between three-phase / two-phase conversion and two-phase / three-phase conversion). The PWM modulation circuit of FIG. 8 is replaced with a processor 1000.
It shows the internal configuration of 301D.

Next, the operation of the current limiter 332 will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 10 is an explanatory diagram of a method of restricting the command value [d] to the allowable value [d] or less, and FIGS. 11 to 14.
Is a flowchart showing a current command value limiting program stored in the memory 1000b of the microprocessor 1000 in FIG. 9, and FIGS. 15, 16, 17, and 18 are process explanatory diagrams of the flowchart.

First, with reference to FIG. 10, a method of limiting the d-axis component of the command value [d] to an allowable value (regular hexagon) or less while keeping it constant will be described. When the command value is given at the point a, the movement is limited to the allowable value or less by moving in parallel to the d axis and moving to the point a '. Also, when the command value is given at point b, the d-axis component cannot be limited to the allowable value or less without changing the d-axis component, so that the change in the d-axis component is minimized as much as possible.
The position is moved to the vertex of the regular hexagon with the smallest d-axis component (if the command value has a positive d-axis component, it is moved to the vertex of the regular hexagon with the largest d-axis component), and is limited to the allowable value or less.

At ST1 and ST3 in FIGS. 11 to 14, the command value (I
_2Ad ^*, I _2Aq ^*), respectively load the ωt, ST30
In this example, a value obtained by dividing ωt by π / 3 is calculated as an integer X. Next, in ST31, the allowable value is set to MAX and ωt =
The vertex (√3 / 2 MAX, √1 / 2 MAX) of a regular hexagon larger than 0 in both the q and d axis components at 0 o'clock is defined as ωt + (π / 6─π
/ 3) ・ Rotate clockwise by X, and at the vertex of a regular hexagon,
The points having the maximum d-axis component are obtained as I _dMAX and I _qdmAX . If the six vertices of the permissible value (regular hexagon) on the dq coordinates at this time are represented by the symbols shown in FIG. 15, the above-mentioned points (I _dMAX , I _qdmAX ) are points (I _dC , I _qC )
Will be shown.

Then, in ST32, the absolute value of I _2Ad ^* and I
_Compare the size of _dMAX. If _IdMAX is larger, ST40
If not, in ST33, it is determined whether the remainder obtained by dividing ωt by π / 6 is zero (when the vertex of the regular hexagon is on the q-axis). Command value limited to

When the conditions of ST33 and ST36 are satisfied, the command value exists in the area a1 in FIG.
At 35, the command value is moved to point A1 in FIG. 16 if the d-axis component of the command value is positive, and to point A3 in FIG. 16 if the d-axis component is negative.

If the condition of ST36 is not satisfied,
In ST37, it is determined whether or not the command value exists in the area a2 in FIG. 16, and if it is in a2, in ST38, only the d-axis component is changed without changing the q-axis component.

If the condition of ST37 is not satisfied, the command value exists in the area a3 in FIG.
In the example, if the d-axis component of the command value is positive, the command value is moved to point A6 in FIG. 16; if the d-axis component is negative, the command value is moved to point A4 in FIG.

Next, if the condition of ST32 is not satisfied, it is determined in ST40 whether or not the vertex of the regular hexagon exists on the q-axis (when the regular hexagon is at the position shown in FIG. 16).
If it exists on the axis, the sign of the q-axis component of the command value is determined in ST44, and if it is positive, it proceeds to ST45, and if it is negative, it proceeds to ST46.

When the condition of ST40 is not satisfied,
In ST41, it is determined whether or not the vertex of the regular hexagon is on the d-axis (when the regular hexagon is at the position in FIG. 17). If it is present on the d-axis, the q-axis component of the command value is determined in ST42. Is determined, if it is positive, the process proceeds to ST57, and if it is negative, the process proceeds to ST58.

If the condition of ST41 is not satisfied, S
At T43, it is determined whether the command value is in the cu area or the cd area in FIG.
If it is at d, the process continues to ST58.

Next, in ST45, the command value is moved in parallel to the q-axis, and the point is shifted on a straight line connecting points A6 and A5 in FIG. 16 and on a straight line connecting points A5 and A4 in FIG. The q-axis component is I
_q10, and I _q11, ST47 the smaller of the I _q10, I _q11
When the value is smaller than _I2Aq ^* (when it is outside the regular hexagon) in _{ST48 to ST51} , it is output as _I2Aq ^* .

In ST46, the q-axis components of the points on the straight line connecting points A3 and A2 in FIG. 16 and the straight line connecting points A2 and A1 in FIG. 16 are defined as I _q12 and I _q13 . I _q12 , I
The smaller of _q13 is determined, and the value of I is determined in ST53 to ST56.
_When greater than _2Aq ^* (when outside the regular hexagon) I _2Aq
Output as ^* .

Next, in ST57, the command value is moved in parallel to the q-axis, and a point B1 and a point B6, a point B6 and a point B5, and a point B5 and a point B4 in FIG. The q-axis components of the point shifted on the connecting straight line are _defined as I _q14 , I _q15 , and I _q16, and the smallest value among them is obtained in ST59, ST60, and ST63.
If the value is smaller than I _2Aq ^* (when the command value is outside the regular hexagon), ST62, ST65, ST67
_Output as _2Aq ^* .

In ST58, the command value is moved in parallel to the q-axis to connect the points B4 and B3 in FIG. 17, the line connecting points B3 and B2, and the points B2 and B1. The q-axis components of the point shifted on the straight line are _defined as I _q17 , I _q18 , and I _q19, and the smallest value among them is obtained in ST68, ST69, and ST72.
If the value is larger than I _2Aq ^* (when the command value is outside the regular hexagon), ST 71, ST 74 and ST 76 perform
_Output as _2Aq ^* .

According to the flowchart of the third embodiment, in addition to the effect of the first embodiment, the command value can be further limited to the allowable value or less without changing the d-axis component (effective component) of the command value. If the d-axis component (effective component) of the command value is limited as in a control circuit, a control problem occurs (FIG. 8).
In this case, the voltage of the DC capacitor 7 cannot be maintained. ) Effective control can be realized for the control system.

Embodiment 4 FIG. FIG. 19 shows another embodiment of the present invention. The components other than the current limiter 333 correspond to those having the same reference numerals in the third embodiment (however, the connection between the three-phase / two-phase converter 205 and the harmonic detection circuit 807 is different from that in the third embodiment). ), The description of which is omitted. In the figure, 333
Is a current limiter that limits the command value to “allowable current value determined by the overcurrent protection level of the electric valve of the converter”,
In the third embodiment, q is maintained while the d-axis component of the command value is kept constant.
The command value is limited to the allowable value or less by means for changing the d-axis component while keeping the q-axis component constant, whereas the axis component is limited to the allowable value or less.

The operation of FIG. 19 will be described. The current (I _L ) supplied to the load is converted by the three-phase / two-phase converter 205 into d.
The current is converted to the -q coordinate, the q-axis component of the load current is directly input to the current limiter 333, and the d-axis component is
At 7, the harmonic I 2 _Ld is obtained only for the harmonic component, and is input to the current limiter 333. Unlike the third embodiment, the DC voltage is compensated by the DC power supply 4. Therefore, there is no problem even if the effective component (d-axis component) of the command value is limited. The command value is limited to the allowable value or less without limiting the (q-axis component).

Then, the deviation between the command value limited by the current limiter 333 to be equal to or less than the allowable current value of the converter and the value of the converter output current detected at 805 on the dq coordinate becomes zero. The current is controlled by a current control circuit 331, and the control signal u-
In a PWM modulation circuit 301D that inputs a digital value on the vw coordinate, the converter 1 outputs a command value (harmonic _Iq + harmonic Id _).
(A value obtained by limiting the + fundamental wave _Iq to an allowable value or less), thereby canceling out harmonic components of the system power supply 6 and improving the power factor.

FIG. 20 is a circuit diagram showing the electrical connection of FIG. In the figure, the signal line of the three-phase AC value is indicated by a single line to which three oblique lines are added. 1,2,4,5,6,501,80
5, 806, correspond to the same reference numerals in FIG. 8, and the description thereof is omitted. Reference numeral 1000 denotes a microprocessor, a CPU 1000d, a memory 1000b, and an input circuit 1000.
a, and an output circuit 1000c. Reference numeral 502 denotes an A / D converter for converting an analog value to a digital value, and 301D a PWM modulation circuit, which includes an oscillator 301Da and an up / down counter 301D.
b, and a digital comparator 301Dc.

Next, the operation of the A / D converter 502, the microprocessor 1000, and the PWM modulation circuit 301D of FIG. 20 will be described. Receiving the converted command value by the A / D converter 502 (load current harmonics I _q, and I _d, the reactive current I _q of the fundamental wave component) at the input circuit 1000a of the microprocessor 1000, in the memory 1000b program In accordance with the processing of each embodiment, a program is performed by the CPU 1000d, and the obtained value is output by the output circuit 1000c to the PWM modulation circuit 301D.
To the digital comparator 301Dc.

The digital comparator 301Dc compares the value of the counter generated by the oscillator 301Da and the up / down counter 301Db with the magnitude of the command value of the converter output current output from the output circuit 1000c, and finds that the command value is larger. A high ("1") signal is output if the signal is low, and a low ("0") signal is output if the signal is small, as many as the number of electric valves in the converter main circuit. As described above, FIG. 20 is a block diagram of a part (a control block diagram between three-phase / two-phase conversion and two-phase / three-phase conversion) in which processing is performed by the microprocessor 1000 in the block diagram of FIG. The PWM modulation circuit shown in FIG.
It shows the internal configuration of 301D.

The operation of the current limiter 333 will now be described with reference to FIGS.
This will be described with reference to FIG. FIG. 21 is an explanatory diagram of a method of restricting the command value [d] to the allowable value [d] or less, and FIGS.
25 is a flowchart showing a current command value limiting program stored in the memory 1000b of the microprocessor 1000 in FIG. 20, and FIGS. 26, 27, and 28 are process explanatory diagrams of the flowchart.

First, with reference to D0, a method for limiting the command value [d] to an allowable value (regular hexagon) or less while keeping the q-axis component constant will be described. When the command value is given at the point c, the command value is limited to a value equal to or less than the allowable value by moving in parallel to the d axis and moving to the point d '. When the command value is given at the point e, it is not possible to limit the q-axis component to an allowable value or less without changing the q-axis component.
Move to the vertex of the regular hexagon with the largest axis component (command value q
If the axis component is negative, the q-axis component is moved to the vertex of the smallest regular hexagon. ), Shall be limited to the allowable value or less. Such a process will be described with reference to FIGS.

Steps ST1, 3, and 21 in FIG. 22 are the same as those in FIGS. 11 to 14, and will not be described here. In ST80, the allowable value is set to MAX, and the vertex of the regular hexagon where both q and d axis components at ωt = 0 are larger than 0 (０3/2 MAX, √1 / 2 MAX)
Is rotated clockwise by ωt−π · (X + 1) / 3,
The point having the maximum q-axis component at the vertex of the regular hexagon is _defined as (I _dqMAX , I
_qmAX ). Then, in ST81, I _2Ad ^*
The magnitude of _IqMAX is compared with the absolute value of _IqMAX. If _IqMAX is greater, the _{process proceeds} to ST89. Otherwise, in ST82, the remainder obtained by dividing ωt by π / 3 is zero (the vertex of the regular hexagon is on the d-axis). ), And if it is not zero, a command value limited to a permissible value or less is obtained in ST83.

When the conditions of ST82 and ST84 are satisfied, the command value exists in the area f1 in FIG.
At 85, the command value is moved to the point F2 or F4 in FIG. 26 (if the q-axis component of the command value is positive, go to F4, and if it is negative, go to F2).

When the condition of ST86 is satisfied, the command value exists in the area of f2 in FIG. 26. Therefore, in ST88, only the q-axis component is changed while the d-axis component is kept constant.

When the condition of ST86 is not satisfied, the current value is in the area of f3 in FIG. 26. Therefore, in ST87, if the q-axis component of the command value is positive, the process goes to F5 in FIG. 26; The command value is moved to F1 in FIG.

Next, in ST89, it is determined whether there is a vertex of a regular hexagon on the d-axis, and if it is on the d-axis, in ST92,
It is determined whether the d-axis component of the command value has a positive or negative value. If the value is positive, the flow proceeds to ST114; if the value is negative, the flow proceeds to ST115.

If the condition of ST89 is not satisfied, it is determined in ST90 whether or not a vertex of a regular hexagon exists on the q-axis. If the vertex exists on the q-axis, the d-axis component of the command value is determined in ST91. If ST is positive, go to ST94; if negative, S
The flow chart continues to T95.

If the condition of ST90 is not satisfied, it is determined in ST93 which of the region hr and the region h1 in FIG. 28 has the command value.
The flowchart is continued to 94 and to ST95 when it is in the area h1.

Next, in step ST94, the command value is moved in parallel to the d-axis, and a point h1 and a point h2, a point h2 and a point h3, and a point h3 and a point h4 in FIG. The d-axis components of the point shifted on the connecting straight line are defined as I _d20 , I _d21 , and I _d22, and the smallest value among them is obtained in ST96, ST97, ST102, and when the value is smaller than I _2Ad ^* (command value Is outside the regular hexagon), ST99, ST101, ST10
4 and is output as _I2Ad ^* .

Next, in step ST95, the command value is moved in parallel to the d-axis, and a point h1 and a point h6, a point h6 and a point h5, and a point h5 and a point h4 in FIG. I _d23 and d-axis components of points transferred on a straight line connecting, I _d24, and I _d25, the largest value among the ST105, ST 106, calculated in ST 109, if the value is I _2Ad ^* greater than (command value Is present outside the regular hexagon), ST108, ST111, S
At T113, it is output as _I2Ad ^* .

Next, in ST114, the command value is moved in parallel to the d-axis, and a point F5 and a point F6 shown in FIG.
The d-axis components of the point shifted on the straight line connecting the point and the point F1 are I ₇ and I ₇
And _8, determine the smallest value among the at ST116, when the value I _2Ad ^* smaller (when the command value is present in the regular hexagonal external), in ST 118, ST120, and outputs it as I _2Ad ^* I have.

In step ST115, the command value is moved in parallel to the d-axis, and the straight line connecting points F4 and F3 in FIG.
The d-axis components of the point shifted on the straight line connecting the point and the point F2 are I ₉ and I ₉
And _10, obtains the largest value among the at ST121, when the value I _2Ad ^* greater than (when the command value is present in the regular hexagonal external), in ST123, ST125, and outputs it as I _2Ad ^* I have.

According to the flowchart of the fourth embodiment, in addition to the effect of the first embodiment, the command value can be further limited to the allowable value or less without changing the q-axis component (effective component) of the command value. to improve the power factor of the system power source as, must be controlled so that the load current I _L of the q-axis component (harmonic I _q, the fundamental wave I _q) is the converter 1 the output, therefore, the command value Effective control for a control system that limits the d-axis component without limiting the q-axis component of (fundamental wave I _q , harmonic I _q , harmonic I _d ) and limits the command value to an allowable value or less. Can be realized.

Embodiment 5 FIG. FIG. 29 shows another embodiment of the present invention. In the figure, the signal lines of the three-phase AC value are indicated by a single line with a triangular line, and all the components other than the current limiter 334 correspond to the same reference numerals in the first and second embodiments. , The description of which is omitted. Current limiter 33
Reference numeral 4 denotes current command value limiting means which receives a command value [d] of the converter output current, which is an output of the adders 703 and 704, as an input. u] Hereinafter, control means for limiting the command value will be described.

In the fifth embodiment, the command value [d] is temporarily set to u
Since a means for comparing the command value [u] with the permissible value [u] on the uvw coordinate after conversion into the vw coordinate is used, a simpler flowchart (short program)
Can be obtained. Also, the electrical connection in FIG. 29 can be configured in the same manner as in FIG. 2 except that the program on the memory 1000b of the microprocessor 1000 in FIG. 2 is different. In addition,
The above-mentioned allowable value [d] is a regular hexagon that rotates clockwise on the dq coordinate at the time and the center of the origin, and the length of one side is √2MAX (MAX is uvw). (Coordinate allowable value).

Next, the operation of the current limiter 334 will be described with reference to FIG. FIG. 30 is a flowchart showing a current command value limiting program stored in the memory 1000b of the microprocessor 1000. ST1 and ST3 in FIG.
The description is omitted because it is the same as that of the fourth embodiment. ST
At 130, the command value [d] is converted to uvw coordinates,
T131, ST132, in ST134, I _u, I _v, the absolute value in the I _w is to select the smallest of things, ST133, ST135, S
In T136, it has its value and I _max. And ST13
7, the magnitude of I _max and MAX (tolerance) is compared, and
If direction of X is large, as the command value because the command value does not exceed the permissible value ^{_{(I 2Ad *, I 2Aq *}} ) outputs,
If MAX is smaller, in ST138, MAX /
Multiplied by I _max d-axis component command value [d], the q-axis component, and limits the command value to the allowable value or less.

Next, a flow chart of the fifth embodiment (FIG. 7)
Is expressed in a program (assembler language), and ADSP21060
Table 2 shows the program execution time in the case of assuming a microprocessor as in the first and second embodiments.

[0131]

[Table 2]

As described above, according to the flow chart of the fifth embodiment, in addition to the effect of the first embodiment, the first and second embodiments are added.
As the program becomes shorter (the program execution time becomes shorter), the program creation time can be further reduced, and the program memory area can be reduced, so that there is an effect that a physically limited memory can be effectively used.

[0133]

Since the present invention is configured as described above, it has the following effects.

According to the third and twelfth aspects of the present invention, as the command value to be given to the current control system, the "converter output current command value" on the rotating coordinates is determined from the "overcurrent protection level of the electric valve." By obtaining a value restricted within the range indicated by “allowable value on rotating coordinates” obtained from “allowable value on UVW coordinates” and “phase of rotating coordinate”, the allowable value [d] is obtained from the conventional example. (Regular hexagon) expands, and the command value can be limited to the required allowable value or less without unnecessarily restricting the current flowing to the converter, and as a result, the electric valve of the converter can be used efficiently. is there.

According to the second aspect of the present invention, at least one phase is a permissible value on the uvw coordinate and the other phase is within the permissible value. By calculating a value obtained by converting the phase exchange value onto dq coordinates,
The allowable value [d] (regular hexagon) is wider than in the conventional example, and the command value can be limited to a required allowable value or less without unnecessarily restricting the current flowing through the converter. There is an effect that it can be used.

Further, according to the first aspect of the invention, the command value on the rotational coordinates is compared with a previously obtained allowable value.
By calculating the value that limits the command value on the rotating coordinates, the ratio of limiting the effective component and the invalid component of the command value can be determined by the movement of the command value on the dq coordinates. It is easy to understand, and therefore, there is an effect that a current command value limiting method according to an infinite number of combinations of the ratios for limiting the valid and invalid components of the command value can be easily created.

Further, according to the fourth aspect of the present invention, a value that limits the command value on the rotating coordinates is determined by comparing the command value on the UVW coordinate with the allowable value , thereby obtaining the value to be limited. The calculation can be simplified and the program of the current command value limiting method can be shortened.
Further, since the program memory area can be reduced, there is an effect that a physically limited memory can be effectively used.

Further, according to the fifth aspect of the present invention, a value for limiting the d-axis component and the q-axis component of the command value on the rotating coordinate at the same ratio is obtained by comparing the command value on the rotating coordinate with the allowable value. Since the ratio of limiting the effective component and the invalid component of the command value is known by the movement of the command value on the dq coordinates toward the origin, the visual understanding of the limiting ratio becomes easy,
Therefore, there is an effect that a current command value limiting method for limiting the effective and invalid components of the command value at the same ratio can be easily created.

According to the sixth aspect of the present invention, the command value on the rotating coordinate is compared with the allowable value by comparing the command value on the rotating coordinate with d.
The ratio of limiting the effective component and the invalid component of the axis component and the command value can be easily understood by the movement of the command value on the dq coordinates. There is an effect that a current command value limiting method according to the combination can be easily created, and useful control can be realized for an application that preferentially controls an effective component or an invalid component of the command value.

Further, according to the seventh aspect, the known permissible value on the rotating coordinate is rotated about the center of the origin of the rotating coordinate, and the command value on the rotating coordinate is calculated by the command value on the rotating coordinate and the permissible value. Since the values for limiting the axis component and the q-axis component at the same ratio are obtained, the ratio of limiting the effective component and the invalid component of the command value can be obtained by moving the command value on the dq coordinates toward the origin. It is easy to visually understand the limiting ratio, and therefore, it is possible to easily create a current command value limiting method for limiting the effective and invalid components of the command value at the same ratio.

Further, according to the eighth aspect, the command value on the rotating coordinate is rotated about the center of the origin on the rotating coordinate, and the d-axis component of the command value on the rotating coordinate is determined by the command value on the rotating coordinate and the allowable value. And the value that limits the q-axis component at the same rate,
The program of the current command value limiting method can be shortened (Table 1).
Further, since the program memory area can be reduced, there is an effect that a physically limited memory can be effectively used.

Further, according to the ninth aspect, the d-axis component and the q-axis component of the command value on the rotating coordinates are limited at the same ratio by comparing the command value on the UVW coordinate with the allowable value. By obtaining the value, the program of the current command value limiting method can be further shortened (Table 2). Therefore, the program creation time can be reduced, and the program memory area can be reduced. There is an effect that a certain memory can be used effectively.

Further, according to the tenth aspect, by comparing the command value on the rotational coordinate with the allowable value , a value for limiting the q-axis component of the command value on the rotational coordinate while limiting the d-axis component is obtained. Accordingly, there is an effect that the reactive current is limited while the effective current of the command value is kept constant, and effective control can be realized in a system that gives priority to the effective current.

Further, according to the eleventh aspect, by comparing the command value on the rotating coordinate with the allowable value , the q-axis component of the command value on the rotating coordinate is fixed and only the d-axis component is limited, so that the command There is an effect that the effective current is limited while the value of the reactive current is kept constant, and effective control can be realized in a system in which the reactive current is prioritized.

[Brief description of the drawings]

FIG. 1 is a converter control circuit block diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing an electrical connection according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing a current command value limiting program stored in a memory of the microprocessor of FIG. 2;

4 is an operation explanatory diagram relating to a method of comparing a command value on a dq coordinate and an allowable value in FIG. 3;

FIG. 5 is a diagram illustrating a comparison condition between a command value and a permissible value on dq coordinates in FIG. 3;

FIG. 6 is a converter control circuit block diagram showing Embodiment 2 of the present invention.

FIG. 7 is a flowchart showing a current command value limiting program stored in a memory of a microprocessor according to the present invention.

FIG. 8 is a converter control circuit block diagram showing a third embodiment of the present invention.

FIG. 9 is a circuit diagram showing an electrical connection of the control circuit of FIG.

FIG. 10 is an explanatory diagram of a method for restricting a command value on dq coordinates to an allowable value or less in a third embodiment of the present invention.

FIG. 11 shows a memory 10 of the microprocessor 1000 in FIG. 9;
6 is a flowchart showing a current command value limiting program stored in 00b.

FIG. 12 shows a memory 10 of the microprocessor 1000 in FIG. 9;
6 is a flowchart showing a current command value limiting program stored in 00b.

FIG. 13 shows a memory 10 of the microprocessor 1000 in FIG. 9;
6 is a flowchart showing a current command value limiting program stored in 00b.

14 is a memory 10 of the microprocessor 1000 in FIG.
6 is a flowchart showing a current command value limiting program stored in 00b.

FIG. 15 is an explanatory diagram of the process of the flowchart in FIG. 11;

FIG. 16 is an explanatory diagram of the process of the flowchart in FIG. 11;

FIG. 17 is an explanatory diagram of the process of the flowchart in FIG. 11;

FIG. 18 is an explanatory diagram of the process of the flowchart in FIG. 11;

FIG. 19 is a converter control circuit block diagram showing a fourth embodiment.

20 is a circuit diagram showing the electrical connection of FIG.

FIG. 21 is an explanatory diagram of a method for restricting a command value on dq coordinates in the fourth embodiment.

FIG. 22 shows memory 10 of microprocessor 1000 in FIG.
6 is a flowchart showing a current command value limiting program stored in 00b.

FIG. 23 shows a memory 10 of the microprocessor 1000 in FIG. 17;
6 is a flowchart showing a current command value limiting program stored in 00b.

FIG. 24 shows a memory 10 of the microprocessor 1000 shown in FIG. 17;
6 is a flowchart showing a current command value limiting program stored in 00b.

FIG. 25 shows a memory 10 of the microprocessor 1000 in FIG.
6 is a flowchart showing a current command value limiting program stored in 00b.

26 is an explanatory diagram of the processing in the flowchart in FIG. 26;

FIG. 27 is an explanatory diagram of the process of the flowchart in FIG. 26;

FIG. 28 is an explanatory diagram of the process of the flowchart in FIG. 26;

FIG. 29 is a converter control circuit block diagram showing Embodiment 5 of the present invention.

30 is a flowchart showing a current command value limiting program stored in a memory 1000b of the microprocessor 1000 of the circuit of FIG. 29.

FIG. 31 is a block diagram of a conventional converter control circuit.

FIG. 32 is a PWM modulation circuit diagram of FIG. 31.

FIG. 33 is another example of a conventional converter control circuit block diagram.

FIG. 34 is an explanatory diagram of a conventional method for restricting a command value on dq coordinates to an allowable value or less.

FIG. 35 is an explanatory diagram of “allowable value” in the present invention.

FIG. 36 is a diagram illustrating a comparison between the present invention and a conventional “permissible value”.

FIG. 37 is an output operation waveform diagram of the current limiter of the present invention and a conventional current limiter.

FIG. 38 is an explanatory diagram in which Expression (29) is plotted on dq coordinates.

[Explanation of symbols]

1 converter main circuit, 2 reactor, 3
Capacitor, 4 DC power supply, 5 load,
6 power system, 7 DC capacitor,
201, 207 two-phase / three-phase converter, 202 to 206
Three-phase / two-phase converter, 301D, 301-334 control circuit, 304 current control amplifier, 306 voltage control amplifier 308,309 current limiter 501 drive circuit, 701-713 adder / subtractor, 801, 802, 805, 806 current detector, 803 , 80
4 Voltage detector, 807 harmonic detection circuit, 10
00 Microprocessor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02M 7/48 H02P 21/00

Claims (12)

(57) [Claims] 1. A current control system for controlling an instantaneous value of an output current of a converter among converters configured to generate an arbitrary three-phase AC output by controlling opening and closing of an electric valve; A method of limiting a current command value of a control system having a load connected via a filter inductance outside the control system, wherein a current command value to be given to the current control system is:
A procedure for limiting an output current command value of the converter on a rotating coordinate within a range indicated by a current allowable value on a rotating coordinate previously obtained from an overcurrent protection level of the electric valve. The current command value limiting method characterized by the following. 2. As a permissible value on a rotating coordinate, at least one phase is determined by a uv determined by an overcurrent protection level of the electric valve.
2. The current according to claim 1, wherein a current allowable value on the -w coordinate is used, and the other phase uses a value obtained by converting a three-phase alternating current value within the current allowable value into a rotational coordinate. How to limit the command value. 3. A current control system for controlling an instantaneous value of an output current of the converter among converters configured to generate an arbitrary three-phase AC output by opening and closing control of an electric valve; A method of limiting a current command value of a control system having a load connected via a filter inductance outside the control system, wherein a current command value to be given to the current control system is:
The d-axis component of the output current command value of the converter on the rotational coordinates and
A method for limiting the q-axis component to within a range indicated by an allowable value on the uvw coordinate determined from the overcurrent protection level of the electric valve and an allowable value on the rotating coordinate obtained from the phase of the rotating coordinate.
A method for limiting a current command value, the method comprising: 4. A current control system for controlling an instantaneous value of an output current of the converter among converters configured to generate an arbitrary three-phase AC output by opening and closing control of an electric valve; A method of limiting a current command value of a control system having a load connected via a filter inductance outside the control system, wherein a current command value to be given to the current control system is:
The output current command value of the above-mentioned converter on the rotational coordinates is expressed by U-V-W
It is converted into the command value on the coordinate and the allowable value on the UVW coordinate is
If the command value is larger than the allowable value,
To limit the command value on the rotating coordinates at a rate of (tolerance / command value)
A method for limiting a current command value, comprising: 5. A method for limiting a current command value according to claim 3.
, The d-axis component of the current command value on the rotational coordinates and q
A method for limiting a current command value, comprising a procedure of limiting an axis component at the same ratio. 6. The method for limiting a current command value according to claim 3.
In, limiting method of the current command value, characterized in that it comprises the steps of limiting in any proportions predetermined d-axis and q-axis components of the command value on the rotating coordinates. Characterized by having a 7. the current threshold value in the known rotating coordinate by rotating the origin center of the rotating coordinate comparing the current command value and the current threshold value procedure
The method for limiting a current command value according to claim 5 . 8. claims the current command value on the rotating coordinates by rotating the origin center of the rotating coordinate characterized by comprising the step of comparing the current command value and the current threshold value 5
Limiting process of current command value according to. 9. The method for limiting a current command value according to claim 4.
In, limiting method of the current command value, characterized by comprising the step of limiting the d-axis and q-axis components of the command value on the rotating coordinates at the same rate. 10. A method for limiting a current command value according to claim 3.
A method of limiting the q-axis component while keeping the d-axis component of the current command value on the rotating coordinates constant. 11. A method for limiting a current command value according to claim 3.
A method of limiting the d-axis component while keeping the q-axis component of the command value on the rotating coordinates constant. 12. A converter configured to generate an arbitrary three-phase AC output by controlling opening and closing of an electric valve,
In a current control system for controlling an instantaneous value of the output current of the converter and a load connected via a filter inductance outside the current control system, u is determined by an overcurrent protection level of the electric valve. Calculate, as the output current command value of the converter on the rotating coordinates, a value limited within the range indicated by the allowable current value on the rotating coordinates obtained from the allowable current value on the vw coordinates and the phase of the rotating coordinates. An apparatus for limiting a current command value of a converter, comprising an arithmetic unit.