JPH09182458A - Controller for current-type converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply constitute a controller, for a three-phase current-type converter, which performs a PWM control operation while a duality with a triangular-wave comparison system in a voltage-type converter is utilized. SOLUTION: In a current-type converter, a DC-AC conversion operation is performed by a three-phase bridge converter, and electric power is supplied to a load. In the current-type converter, phase current command values iuw*, ivu*, iwv* are obtained by a subtracter 1, a comparator 4 compares them with triangular waves to be output by a triangular-wave carrier signal generator 3, and three-phase PWM phases Suw, Suv, Swv are obtained. A logic circuit determines the logical product of the negation signal, on one side, and the signal, on the other side, of two-phase PWM pulses which are different from the three-phase PWM pulses, and signals Su1<+> , Su1<-> ,..., Sw1<-> are output. On the other hand, in order to guarantee the continuity of the current of a DC current source, short-circuit pulses are generated by a short-circuit pulse generation circuit 6, they are synthesized with the signals Su1<+> , Su1<-> ,..., Sw1<-> , and signals Su<+> , Su<-> ,..., Sw<-> which drive switching elements at the converter are obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a V for an induction motor.
The present invention relates to a control device for an inverter or converter device used in a VVF (variable voltage variable frequency) device or various power supply devices, and particularly to a control device for a current source converter that controls current by performing PWM modulation. is there.

[0002]

2. Description of the Related Art One example of a three-phase current source converter that controls by performing PWM modulation is, for example, edited by The Institute of Electrical Engineers of Japan, published by The Institute of Electrical Engineers of Japan, "Semiconductor Power Converter Circuit" (March 31, 1987).
212-214 of the first edition published). Although a converter is shown in the same document, the same type of control device can be used also in the inverter, only by switching the power supply and the load and changing the power transmission direction. Alternatively, the converter can be regarded as a state in which the inverter is performing a regenerative operation, and the inverter and the converter can be controlled by basically the same kind of control device. . Details of the control device can also be found in, for example, the Institute of Electrical Engineers of Japan, Volume D107, No. 11 (1987).

In addition, 21 of the above "semiconductor power conversion circuit"
In the control device seen in Figure 9.2.24 on page 3,
The sine wave pattern pulse P and the triangular wave signal stored in advance in the ROM are read by the output pulse of the PLL circuit synchronized with the power supply, and the triangular wave signal is compared with the function generator I for controlling the DC voltage to generate a short circuit pulse. The generated sine wave pattern pulse and the short circuit pulse are combined in a combining circuit to generate a gate signal for driving the switching element. It should be noted that, in FIG. 9.2.24, the phase control circuit except the phase shift circuit is necessary because of the restriction of the minimum ON width and OFF width of the switching element and is not directly related to the present invention.

[0004]

As is apparent from the matters described in the above-mentioned two documents, the control device of the conventional current source converter which performs the PWM modulation does not include the sine wave pattern pulse and the short circuit pulse. Each of them is created in a separate way, and these are combined by a combining circuit. Also, when combining, within one cycle of 360 degrees of the AC power supply voltage or the AC output voltage created by the phase shift circuit. The synthesizing circuit needs the information of which 60 degree period of time, and it becomes a very complicated control device.

On the other hand, in the conventional three-phase voltage type converter for performing PWM modulation, as shown in FIG. 6.3.5 on page 114 of "Semiconductor Power Conversion Circuit" published by the Institute of Electrical Engineers,
Basically, the triangular wave carrier signal es and the voltage command value e _O u
, E _o v, e _o drive signal of the switching element only magnitude relation between w by configuring the transducer vu, vv, vw
Therefore, it is possible to obtain a very simple control device as compared with the current source converter.

In contrast to the voltage type converter described above, in the current type converter, the PWM pattern is created only by the magnitude relationship between the triangular wave carrier signal and the current command value of each phase to obtain the drive signal of the switching element. Then, since the current of each phase is strongly influenced by the switching of the other phase, it does not follow the PWM pattern, and the current command value and the actual current do not match.
Further, in the current type, it is necessary to add a short circuit to guarantee the current continuity of the DC current source and the DC current load. The present invention has been made in consideration of the above-mentioned problems of the prior art, and the present invention is a three-phase current capable of performing PWM control easily at approximately the same scale by means similar to the voltage source converter. The purpose is to obtain a control device for a shape converter.

[0007]

FIG. 1 is a diagram showing the overall configuration of a control device according to the present invention. In the figure, 1 is a current command generator that generates line current command values iu ^* , iv ^* , iw ^* of the load. The current command generator 1 uses, for example, an output of a motor speed control circuit (not shown) as a load. It is driven and generates a current command value such that the motor speed reaches a predetermined value. In addition to the speed control circuit, various types such as a position control circuit, a torque control circuit, and a current control circuit can be used according to the application.

Reference numeral 2 is a line current finger output from the current command generator 1.
Phase current command value iuw^*, Ivu ^*, Iwv^*Occurs
A subtractor, 3 is a triangular wave carrier signal generator, 4 is a phase signal
Flow command value and triangular wave carrier signal are compared and their magnitude relation
Generates ON / OFF signals Suw, Svu, Swv for each phase according to
It is a comparator. Also, 5 is from the on / off signal of each phase
Signal Su1⁺, Su1^-, Sv1⁺, Sv1^-, Sw1⁺, Sw1^-
A logic circuit 6 for generating a short circuit pulse Su0, S
Short circuit pulse generation circuit for generating v0 and Sw0, 7 is the above logic
The outputs of circuit 5 and short-circuit pulse generation circuit 6 are combined and
Drive signal Su of the switching element that constitutes the system⁺, S
u ^-, Sv⁺, Sv^-, Sw⁺, Sw^-Synthesis circuit to obtain
It is.

Each of the above-mentioned elements 1 to 7 only performs a simple operation, and is a general-purpose IC chip, which can be constituted by an extremely small number of parts. As described above, the control device for the current source converter usually has a more complicated structure than the control device for the voltage source converter.
The control device of the current source conversion device can be configured with the simple configuration as described above. Hereinafter, the reason will be described.

FIG. 2 is a diagram showing the main circuit configuration of the voltage source converter and the main circuit configuration of the current source converter according to the present invention.
FIG. 2A shows the main circuit configuration of a voltage source converter which is a reference of the present invention, and FIG. 2B shows the main circuit configuration of a current source converter according to the present invention. In the figure, 21 is a DC voltage source, 41 is a DC current source, 22-27, 42-47.
Are switching elements, 28-33 are anti-parallel diodes for reactive power processing, 48-53 are series diodes for obtaining reverse breakdown voltage of the switching elements, 34-36, 54-5.
6 is a load. In FIG. 2, the voltage source converter shown in FIG. 2 (a) and the current source converter shown in FIG. 2 (b) are relative circuits with respect to voltage and current. Each corresponds.

[0011]

[Table 1]

FIG. 3 is a diagram showing waveforms of respective parts of the voltage type and current type converters, and FIG. 4 is a diagram showing a principle of generating a short circuit pulse. In FIG. 3, the symbols on the left side are for the voltage type converter, and the symbols on the right side are for the current type converter. Further, FIG. 4 is an enlarged view of a portion of FIG. It should be noted that FIG. 4 shows a short-circuit pulse (shaded portion in the figure) described later, and the current value is shown as a substantially constant value during this period.

Next, based on the above table, the operation of the conventional voltage source converter will be described with reference to the waveform diagram of FIG. If the command line voltage effective value of the voltage source converter is V ^* , the voltage phase is θ, the phase voltage command values are vu ^* , vv ^* , vw ^* , and the line voltage command values are vuv ^* , vvw ^* , vwu ^*. , These are expressed by the following equations (1), (2) and (3) (in the following equation, √ (2
/ 3) indicates the square root of 2/3. same as below). vu ^* = 1/3 (vuv ^* −vwu ^* ) = √ (2/3) V ^* sin (θ−π / 6) (1) vv ^* = 1/3 (vvw ^* −vuv ^* ) = √ ( 2/3) ・ V ^* sin (θ-5π / 6) (2) vw ^* = 1/3 (vwu ^* −vvw ^* ) = √ (2/3) ・ V ^* sin (θ-3π / 2) ( 3)

In the voltage type converter, as shown in FIG. 3 (a), the phase voltage command values vu ^* , vv ^* , vw ^* and the amplitude ± VDC / shown in the above equations (1) to (3). The two triangular wave carrier signals are compared, and the magnitude relationship is shown in FIG.
(B) Pulse signals Su, Sv, Sw shown in (c) (Sw is not shown in the figure) are generated. For example,
In the figure, the pulse signal Su is generated when the phase voltage command value vu ^* of the U phase is larger than the triangular wave carrier signal, and the pulse signal Sv is generated when the phase voltage command value vv ^{* of} the V phase is larger than the triangular wave carrier signal. By these pulse signals, the switching elements 22 and 2 shown in FIG.
4, 26, and the pulse signals Su, Sv,
Switching elements 23, 25, 2 by the negative signal of Sw
By driving 7 as the load phase voltage, a PWM similar to the sine wave phase voltage command values vu ^* , vv ^* , vw ^*
A modulated approximate sine wave (not shown) can be obtained.

Here, the phase voltage command values vu ^* , vv
^* , Vw ^* and line voltage command values vuv ^* , vvw ^* , vwu ^*
Have the following relationships: ^{vuv * = vu * -vv * =} √ (2) · V * sin θ (4) vvw * = vv * -vw * = √ (2) · V * sin (θ-2π / 3) (5) vwu * = Vw ^* -vu ^* = √ (2) V ^* sin (θ-4π / 3) (6) The load line voltage vuv has a PWM waveform as shown in FIG. 3 (j). Is an approximate sine wave similar to the command value vuv ^* , as can be seen from the equation (4). The same applies to the line voltages vvw and vwu. In this way, the voltage-type converter obtains a sinusoidal line voltage that approximates the command value.

Next, the above voltage source converter and the duality of Table 1
Based on, the operation of the current source converter will be described. Figure
In the current command generator 1 shown in 1, the above (4) to (6)
Line current command value iu corresponding to the formula^*, Iv^*, Iw^*Depart
Live. This is the effective value of the command line current I^*, Current phase θ
Then, it is expressed by the following equation. iu^*= Iuw^*-Ivu^*= √ (2) ・ I^*sin θ (7) iv^*= Ivu^*-Iwv^*= √ (2) ・ I^*sin (θ-2π / 3) (8) iw^*= Iwv^*-Iuw^*= √ (2) ・ I^*sin (θ-4π / 3) (9) As a result, the phase current corresponding to the expressions (1) to (3) described above is obtained.
Flow command value iuw^*, Ivu ^*, Iwv^*Can be expressed as
it can. iuw^*= 1/3 (iu^*-Iw^*) ＝ √ (2/3) ・ I^*sin (θ-π / 6) (10) ivu^*= 1/3 (iv^*-Iu^*) ＝ √ (2/3) ・ I^*sin (θ-5π / 6) (11) iwv^*= 1/3 (iw^*-Iv^*) ＝ √ (2/3) ・ I^*sin (θ-3π / 2) (12)

The subtractor 2 shown in FIG. 1 has a command value iuw ^* ,
ivu ^* , ivv ^* are obtained from the line currents iu ^* , iv ^* , iw ^* and the command line current effective value I ^* by the above equations (10) to (12), and the obtained command values iuw ^* , ivu ^* , iwv ^* are Comparator 4
, The pulse signal Suw, which is compared with the triangular wave carrier signal output from the triangular wave carrier signal generator 3 shown in FIG.
Svu and Swv are generated.

3 (b) and 3 (c) show the pulse signal Suw,
It is a figure which shows Svu (Swv is not shown), These pulse signals are the logic circuits 5 of FIG.
Drive signals Su1 ⁺ , Su1 of the switching element shown in (g)
^{-, Sv1 +, Sv1 -,} Sw1 + ( not shown), Sw1 ^- is converted to (not shown), in FIG. 2 switching element 42-4
7 is driven. In the logic circuit 5, the drive signal Su1
^The logical expressions for generating ⁺ , Su1 ⁻ , Sv1 ⁺ , Sv1 ⁻ , Sw1 ⁺ , Sw1 ⁻ are as follows. In the formula below, NOT
(Sxy) indicates the negation of Sxy. ^{Su1 + = Suw · NOT (Svu} ) (13) Su1 - = NOT (Suw) · Svu (14) Sv1 + = Svu · NOT (Swv) (15) Sv1 - = NOT (Svu) · Swv (16) Sw1 + = Swv · NOT (Suw) ( 17) Sw1 - = NOT (Swv) · Suw (18)

As described above, the control circuit of the current source converter for performing the PWM modulation can be realized relatively easily with the configuration shown in FIG. Here, in the current source converter, since the DC power supply 41 shown in FIG. 2B is a current source, all of the positive side switching elements 42, 44 and 46 shown in FIG. If all the switching elements 43, 45, and 47 are turned off at the same time, an overvoltage is caused by abruptly cutting off the DC power supply. Therefore, such an operation cannot be performed.

Referring to FIG. 4 which is an enlarged view of the portion of FIG. 3, in the period in which the triangular wave carrier signal becomes larger than all the phase current command values iuw ^* , ivu ^* , iwv ^* from time t3 to t4, the pulse is generated ^. All of the signals Suw, Svu, Swv are turned off. When all the pulse signals Suw, Svu, Swv are turned off, as is clear from the equations (13) to (18), Su1
^{All of +} , Su1 ⁻ , Sv1 ⁺ , Sv1 ⁻ , Sw1 ⁺ , and Sw1 ⁻ also become L, and all switching elements are turned off, which causes overvoltage. Therefore, as described above, during the period in which all the switching elements are off, a short-circuit pulse that simultaneously turns on the positive and negative switching elements of either phase is provided, and the short-circuit pulse secures the current path of the direct current source 41. There is a need to. Even if the triangular wave carrier signal is smaller than all phase current command values, Suw, Svu, Swv
Since the negative signal of is turned off, it is similar to the above. Also,
A short circuit pulse is also required when the converter is operating as a converter to drive a current load.

[0021] Therefore, as shown in FIG. 1, a short pulse generation circuit 6 is provided to generate a short pulse SU0, Sv0, Sw0, the signal ^{Su1 +, Su1 -, Sv1 +} , Sv1 -, Sw
1 ⁺ , Sw1 ⁻ and the synthesizing circuit 7 synthesize the switching element drive signals Su ⁺ , Su ⁻ , Sv ⁺ , Sv ⁻ , Sw.
^+, Sw ^- obtained. Although any phase may be short-circuited from the viewpoint of preventing overvoltage, it is desirable to select a phase in which the number of switching times of the element does not increase from the viewpoint of reducing switching loss of the switching element.

This will be described with reference to FIG. In addition, in FIG.
Signal Su⁺, Su^-, Sv⁺, Sv ^-, Sw⁺, Sw^-
Are drive signals Su1 shown in FIG.⁺, Su1^-, Sv1⁺, S
v1^-Is a signal with a short-circuit pulse added to the
Indicate the short circuit pulse), S is a triangular wave carrier
A signal that indicates whether the signal is rising or falling
You. At time t3 in FIG. 4, the pulse signal Suw operates.
Then Su⁺And Sw^-Switches from H to L
Then, the U phase or the W phase is selected as the short-circuited phase. This
Su⁺Or Sw^-Does not switch to the H state
Keep it, Su^-Or Sw⁺Switches from L to H
The switch without increasing the number of switching operations.
It is possible to perform a touching operation.

On the other hand, when the V phase is selected, Sv ⁺ ,
Since both Sv ⁻ must be switched from L to H, the number of times of switching increases. Which of the U phase and the W phase is selected is preferably the U phase from the viewpoint that the switching time interval is not shortened. That is, as shown in FIG. 4, Su ⁺ performs switching at t2 close to time t3, but Sw ⁻ performs switching at t1 far from time t3, and Su ⁺
Is maintained in the H state, the switching time interval can be lengthened. Therefore, it is desirable not to switch Su ⁺ at time t3.

Thus, from time t3 to t4,
A short circuit pulse is created in the U phase as shown by the braid in FIG. Short-circuit pulses can be created at other times according to the same idea. S shown in FIGS. 3 (h) and (i)
u0 and Sv0 represent the short-circuit pulse generated as described above, and the W-phase short-circuit pulse Sw0 is omitted in the figure. As described above, P shown in FIGS.
By the WM pulse and the short circuit pulse shown in (h) and (i),
An approximate sinusoidal line current iu similar to the line current command value iu ^* shown in FIG. 9 (j) can be obtained without generating an overvoltage. In the above description, the inverter was mainly described as the current source converter, but the converter can be similarly considered.

The present invention comprises a control device for a current source converter based on the above principle. In the present invention,
The above-mentioned problems are solved as follows. (1) A PWM pulse signal is generated by comparing a load phase current value or a current command value converted into a phase current with a triangular wave carrier signal, and one negative signal of two different PWM pulse signals of the PWM pulse signals is generated. And the other PWM pulse signal, the drive signal of each switching element forming the inverter or the converter is obtained. (2) In the above (1), the positive / negative of a predetermined phase of the converter is in a period in which any of the three-phase load, the power supply phase current command value, or the current command value converted into a phase current is larger or smaller than the triangular wave carrier signal. It drives both switching elements on both sides. (3) In (2) above, the phase that drives the switching elements on both the positive and negative polarities is selected so that the number of times of switching is small.

According to the first and second aspects of the present invention, since the configuration is as described in (1) above, the three-phase current source converter can be constructed with a simple configuration substantially equivalent to the voltage source converter. PWM control can be performed. According to the invention of claim 3 of the present invention, since it has the configuration of (2) above, it is possible to obtain a short-circuit pulse for preventing an overvoltage of the current source converter with a simple configuration. In the invention of claim 4 of the present invention,
With the configuration of (3) above, the number of times of switching can be reduced and the switching loss can be reduced.

[0027]

FIG. 5 is a diagram showing an embodiment of the present invention, in which the logic circuit 5, the short circuit pulse generating circuit 6 and the synthesizing circuit 7 shown in FIG. 1 are shown. FIG.
As the current command generator 1, the subtractor 2, the triangular wave carrier signal generator 3, and the comparator 4 shown in FIG. 1, well-known means used in the conventional PWM modulation three-phase converter can be used. It can be easily configured by a general-purpose chip that is integrated into an IC. In FIG. 5, 61 to 64 are NOT gates, 60 to 70, 71, 72, 79 to 84 are AND gates, 73 and 74 are NOT gates, and 75 to 7
8 is a D flip-flop circuit, 85-93 are OR gates, Suw, Svu, Swv are the outputs of the comparator 4 shown in FIG. 1, and S is the rising triangular wave carrier signal shown in FIG. Is a signal indicating whether or not.

In the figure, the NOT gates 61 to 63 and the AND gates 65 to 70 are used for the above (13) to (1).
The logic circuit 5 for calculating the equation 8) is configured and the PWM pulse S
u1 ⁺ , Su1 ⁻ , Sv1 ⁺ , Sv1 ⁻ , Sw1 ⁺ , Sw1 ⁻ are generated. Further, the NOT gate 64 and the AND gates 71 and 7
2, 79 to 84, NOT gates 73 and 74, D flip-flop circuits 75 to 78, and OR gate 8
The short-circuit pulse generation circuit is composed of 5 to 87, and the short-circuit pulse S
u0, Sv0, Sw0 are generated. Also, the OR gate 88-
The synthesizing circuit 7 is composed of 93, and PWM pulses Su1 ⁺ , Su1
^{-, Sv1 +, Sv1 -,} Sw1 +, Sw1 - a short-circuit pulse Su
0, Sv0, Sw0 are combined to generate drive signals Su ⁺ , Su ⁻ , Sv ⁺ , Sv ⁻ , Sw ⁺ , Sw ⁻ for the switching elements.

Next, the operation of the logic circuit of the embodiment shown in FIG.
This will be described with reference to FIG. PWM pulse signal Suw,
When Svu and Swv are input, the negation gates 61 to 64 are turned on.
Negative signal NOT (Svu), NOT (Suw), NOT (Svu)
I do. The AND gates 65 to 70 have the above NOT (Svu), NO.
By T (Suw), NOT (Svu) and Suw, Svu, Swv,
The logical product operation shown in equations (13) to (18) is performed, and Su
 ⁺, Su^-, Sv ⁺, Sv^-, Sw⁺, Sw^-Generate
You. On the other hand, when the triangular wave carrier signal is rising, the signal S is
It is H level, and in this state, the signal Swv is generated at time t1.
Operates and changes from H level to L level. Signal Swv changes from H to L
When it becomes a bell, the output of the AND gate 72 of FIG.
It changes from H to L regardless of H and L of Suw and Svu. this
At this time, the output of the negation gate 64 is H because the signal S is H.
The output of the NOR gate 74 changes from L to H, and D
Latch clock pulse to the flip-flop circuits 78 and 77
Is given.

At this time, the D input of the D flip-flop circuit 77, that is, the output of the NOT gate 63 is H because Swv is L, and the Q output of the D flip-flop circuit 77 is also H from L. At time t3 in this state, all of Suw, Svu, and Swv become L, and the negative gate 6
Since all the outputs of 1 to 63 are H, the output of the AND gate 71 is also H and the output of the AND gate 82 is H.
This signal is output as a short circuit pulse Su0 via the OR gate 85. This short circuit pulse Su0 is the OR gate 8
At 8 and 89, the logical sum of the signals Su1 ⁺ and Su1 ⁻ is obtained and output as drive signals Su ⁺ and Su ⁻ .

The same applies to the other short-circuit pulses Sv0 and Sw0. For example, for the short-circuit pulse Sv0, when the signal Suw operates at time t4 when the signal S is at the L level and changes from the L level to the H level, The output changes from H to L,
Since the output of the NOR gate 73 changes from L to H, D
A latching clock pulse is applied to the flip-flop circuits 75 and 76. At this time, since the D input of the D flip-flop circuit 76 is H, the D flip-flop circuit 76
Q output of is set to H, and in this state, Suw, Svu, S
When all of wv become H, the output of the AND gate 72 becomes H and the output of the AND gate 80 becomes H. This signal is output as a short circuit pulse Sv0 via the OR gate 86.

In the above embodiment, the case where the logic circuit 5 is composed of logic elements such as a logical sum gate and a logical product gate is shown, but the above logical operation can be realized by software using a microprocessor or the like. You can also Also,
The means for generating the short-circuit pulse is not limited to the above-mentioned embodiment, and the point is to provide means for preventing all the switching elements from being turned off at the same time.

[0033]

As described above, in the present invention, the PWM pulse signal is generated by comparing the load phase current value or the current command value converted into the phase current with the triangular wave carrier signal, and the PWM pulse signal is generated. Since the logical product of one negative signal of the two-phase PWM pulse signals different from each other and the other PWM pulse signal is obtained to obtain the drive signal of each switching element forming the converter, it is almost the same as the voltage type converter. A current source converter controlled by PWM modulation can be realized by a similar relatively simple control device. Also, drive both the positive and negative polarity side switching elements of the specified phase of the converter during the period when the three-phase load, the power supply phase current command value, or the current command value converted into a phase current is larger or smaller than the triangular wave carrier signal. By doing so, it is possible to obtain a short-circuit pulse that prevents an overvoltage of the current source converter with a simple configuration. Furthermore, by selecting a phase in which the number of times of switching increases little as the phase for driving the switching elements on both the positive and negative sides, the number of times of switching can be reduced and the switching loss can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a control device of the present invention.

FIG. 2 is a diagram showing a main circuit configuration of a voltage type and current type converter.

FIG. 3 is a diagram showing waveforms of various parts of a voltage type and current type converter.

FIG. 4 is a diagram illustrating a principle of generating a short circuit pulse.

FIG. 5 is a diagram showing a configuration of a logic circuit in a control device that is an embodiment of the present invention.

[Explanation of symbols]

 1 Current command generator 2 Subtractor 3 Triangular wave carrier generator 4 Comparator 5 Logic circuit 6 Short-circuit pulse generation circuit 7 Synthesis circuit 21 DC voltage source 22-27, 42-47 Switching element 28-33, 48-53 Diode 34- 36,54-56 Load 41 Direct current source 61-64 Negative gate 65-72,79-84 Logical product gate 73,74 Negative OR gate 85-93 Logical OR gate 75-78 D flip-flop circuit

Claims (4)

[Claims] 1. A PWM modulation three-phase current source converter for supplying AC power to a load from a DC current source via an inverter, wherein a load phase current command value or a current command value converted into a phase current and a triangular wave carrier signal A PWM pulse signal is generated by comparison, a logical product of one negative signal of the two different phase PWM pulse signals of the PWM pulse signals and the other PWM pulse signal is obtained, and the inverter is calculated by the logical product calculation result. A control device for a current source converter, characterized in that a drive signal for each of the constituent switching elements is obtained. 2. A PWM modulation three-phase current source converter for supplying DC power to a load from an AC voltage source through a converter, wherein a power supply phase current command value or a current command value converted into a phase current and a triangular wave carrier signal A PWM pulse signal is generated by comparison, and a predetermined two-phase PWM that is different among the PWM pulse signals is used.
Control of a current source converter characterized in that a logical product of one negative signal of the pulse signals and the other PWM pulse signal is obtained, and a drive signal for each switching element constituting the converter is obtained based on the logical product calculation result. apparatus. 3. A positive / negative bipolar side switching element of a predetermined phase of the converter during a period in which either the three-phase load, the power supply phase current command value, or the current command value converted into a phase current is larger or smaller than the triangular wave carrier signal. The control device for the current source converter according to claim 1 or 2, which drives both of them. 4. The control device for the current source converter according to claim 3, wherein a phase in which the number of times of switching is small is selected as a phase for driving the switching elements on both the positive and negative sides.