RU2699374C1 - Device for control of high-voltage frequency converter - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering and can be used to control three-phase three-level active rectifier of high-voltage frequency converter, control system of which during short-term asymmetric mains voltage failures switches operating mode of active rectifier switches from pulse-width control method to relay-vector control. Technical result is improvement of reliability and operation speed of three-phase three-level active rectifiers at short-term asymmetric power supply voltage failures. Device is equipped with control system of high-voltage frequency converter 11 at asymmetric voltage of power supply. Said system comprises: unit (12) for calculating active and reactive components of currents of power supply; phase locked loop (13) and generating sector number unit (13); relay regulators (14, 15) of active and reactive currents; unit (16) of preliminary selection of basic vector of voltage of active rectifiers; unit (17) for calculation of specified value of active current and state of balance of voltages on capacitors of DC link; unit (18, 19) for selection of basic voltage vectors for active voltage rectifiers of the first and second frequency converters and generation of control signals by switches of said rectifiers; Storage units (20, 21) of their previous values of basic stress vectors.

EFFECT: device provides higher reliability and operating speed of three-phase three-level active rectifiers of high-voltage frequency converter at short-time asymmetric voltage drops of power supply source; besides, the device provides high power factor, practically sinusoidal current form consumed from the network.

1 cl, 10 dwg

Description

The invention relates to the field of power converting equipment and can be used to control three-phase three-level active voltage rectifiers of a high-voltage frequency converter, the control system of which, for short-term asymmetrical voltage dips, switches the mode of operation of the keys of active rectifiers from a pulse-width control method to relay-vector control.

A control device for a three-phase active voltage rectifier is known, which contains current and voltage sensors of a power source, a rectified voltage sensor, a pulse-width modulator, a rectified voltage regulator and a reactive current generator of a power source, a control system including a unit for extracting symmetrical components of the voltage of the forward and reverse sequences in a curve voltage source, phase locked loop, power conversion unit coordinate systems abc into a rotating coordinate system dq, a block of proportional-integral controllers of the active and reactive components of the power supply current, a unit for converting direct sequence control voltages from a rotating coordinate system dq to a fixed coordinate system αβ, the first and second adders, a unit for converting control voltages from a fixed coordinate system αβ to the coordinate system abc and the unit of proportional-integral regulator of rectified voltage (see RF patent No. 161102, H02M 7/00).

A disadvantage of the known device is the low reliability of its operation with short-term asymmetrical voltage drops of the power source, which is due to a significant increase in the first harmonic of the individual phase currents of the active rectifiers and a significant voltage fluctuation of the DC link, which leads to the disconnection of the active rectifiers.

The closest analogue to the claimed invention is a control device for a high-voltage frequency converter, comprising a voltage sensor of the power source, the input of which is connected to the output of a three-phase power source, and the output to the voltage asymmetry calculation unit of the power source, the first output of which is connected to the first input of the frequency converter control system at a symmetrical voltage of the power source, and the second output is with the voltage regulator of the DC link, the output of which is connected with the second input of the specified control system of the frequency converter, the first and second outputs of the specified control system are connected respectively to the first and second control inputs of the high voltage frequency converter, the power input of which is connected to a power source, and the power output to a synchronous machine, to the first information output of the high voltage converter frequency through the current sensor 8 of the power source connected to the third input of the control system of the frequency converter, the fourth input of the specified system pack The power supply is connected to the output of the voltage sensor of the power source, and the fifth input is to the output of the voltage sensor of the DC link, three inputs of which are connected to the second, third and fourth information outputs of the high-voltage frequency converter, the sixth input of the frequency converter control system with a symmetrical voltage of the power source is connected to reactive current regulator (see RF patent No. 157682, H02M 5/458).

A disadvantage of the known device is its low reliability and low speed operation with short-term asymmetrical voltage drops of the power source. This is due to a significant increase in the first harmonic of the individual phase currents of the active rectifiers, a significant fluctuation in the voltage of the DC link and a significant unbalance of the voltages on the capacitors of the DC link, which leads to the disconnection of three-phase three-level active rectifiers and disruption of the high-voltage frequency converter.

In the known device seven cases of asymmetry of the voltage of the power source are considered. The new switch angles α1, α2, ..., α9 for a given range of modulation factor µ of the phase voltages of the active rectifier were previously calculated and stored in the phase voltage correction block of the active rectifiers. The new switching angles of the keys limit the increase in the first harmonic of the individual phase currents of the active rectifiers, and also limit the significant voltage fluctuations of the DC link, i.e. increase the reliability of the rectifier.

However, seven cases of asymmetry in the voltage of the power supply is a very small fraction of the possible options for single-phase, two-phase, or three-phase asymmetrical voltage dips. As indicated in the known device for calculating new switching angles of the keys α1, α2, ..., α9 of the active rectifier for each phase, a system of nonlinear equations is written. In this case, the first harmonic of the phase voltage A1 = µ (2U _dc ) / π is set by the modulation coefficient µ, and harmonics with “undesirable” numbers are deleted or their levels are reduced to a predetermined value. Determining the type and depth of an asymmetric voltage dip in real time, as well as solving a system of nonlinear equations, is carried out by iterative methods and takes time to calculate new key switching angles, which reduces the speed of operation of the control system and the entire device as a whole.

Thus, in the known device, it is necessary either to pre-calculate and save in the phase voltage correction block all possible cases of asymmetry, or to calculate the new switching angles of the keys α1, α2, ..., α9 of the active rectifier upon the failure of the supply voltage, which represents a certain implementation difficulty . Based on the foregoing, it follows that the reliability and performance of the known device is low.

The technical problem solved by the claimed device is to increase the reliability and speed of operation of three-phase three-level active rectifiers with short-term asymmetrical voltage drops of the power source.

The technical result consists in creating conditions for short-term asymmetrical voltage drops of the power supply, providing: limiting the increase in the first harmonic of the individual phase currents of the active rectifiers, limiting the range of voltage fluctuations of the DC link, as well as reducing the imbalance of voltage on the capacitors of the DC link to acceptable limits, so that eliminate emergency shutdown of three-phase three-level active rectifiers and increase the reliability of high-voltage operation of the frequency converter.

The problem is solved in that the control device of the high-voltage frequency converter, comprising a voltage sensor of the power source, the input of which is connected to the output of the three-phase power source, and the output to the voltage asymmetry calculation unit of the power source, the first output of which is connected to the first input of the frequency converter control system at symmetrical voltage of the power source, and the second output with a voltage regulator of the DC link, the output of which is connected to the second input of the decree of the control system of the frequency converter, the first and second outputs of the specified control system are connected respectively to the first and second control inputs of the high-voltage frequency converter, the power input of which is connected to a power source, and the power output to a synchronous machine, to the first information output of the high-voltage frequency converter via a sensor the power supply current is connected to the third input of the frequency converter control system, the fourth input of the specified control system is connected to an ode to the voltage sensor of the power source, and the fifth input to the output of the voltage sensor of the DC link, three inputs of which are connected to the second, third and fourth information outputs of the high-voltage frequency converter, the sixth input of the frequency converter control system with a symmetrical voltage of the power source is connected to the reactive current regulator , according to the invention, it is equipped with a control system for a high voltage frequency converter with an asymmetrical voltage of the power source, including a unit for calculating the active and reactive components of the currents of the power source, the first input of which is connected to the output of the current sensor of the power source, and the second input with the first output of the phase-locked loop and the formation of the sector number on the third plane of the base vectors, the input of this unit is connected to the output of the source voltage sensor power supply, the first and second outputs of the unit for calculating the active and reactive component currents are connected respectively to the first inputs of the relay controller of the active current and relay reactive current regulator, the outputs of which are connected respectively to the first and second inputs of the preliminary selection of the base voltage vector of the active rectifiers of the high-voltage frequency converter, the third input of the preliminary selection of the base voltage vector is connected to the second output of the phase-locked loop and the formation of the sector number on the third plane of the base vectors while the second input of the relay controller of the active current is connected to the first output of the unit for calculating the set value active current and the state of the voltage balance on the capacitors of the DC link of the high-voltage frequency converter, the first input of the specified calculation unit is connected to the output of the voltage regulator of the DC link, while the second input of the relay reactive current regulator is connected to the output of the reactive current regulator, the first output of the preliminary selection unit the base voltage vector of the active rectifiers of the high-voltage frequency converter is connected to the first input of the base vector selection unit voltage for the active voltage rectifier of the first frequency converter and the formation of control signals with the keys of the specified rectifier, the second output of the preliminary voltage selection block of the base voltage vector of the active rectifiers of the high voltage frequency converter is connected to the first input of the base voltage vector selection block for the active voltage rectifier of the second frequency converter and the formation of control signals with keys the specified rectifier, the second inputs of the specified blocks select base a voltage torus is connected to the second output of the unit for calculating the set value of the active current and the state of the voltage balance on the capacitors of the DC link of the high-voltage frequency converter, the second input of the specified unit of calculation is connected to the output of the voltage sensor of the DC link, the first output of the base voltage vector selection unit for the active voltage rectifier the first frequency converter and the formation of control signals with the keys of the specified rectifier through the storage unit of its previous The lower value of the base voltage vector is connected to its third input, while the second output of the base voltage vector selection block for the active voltage rectifier of the first frequency converter and the formation of control signals by the keys of this rectifier is connected to the first control input of the high voltage frequency converter, the first output of the base voltage vector selection block for an active voltage rectifier of the second frequency converter and the formation of control signals with the keys of the specified rectifier through a storage unit of its previous value of the base voltage vector is connected to its third input, the second output reference voltage vector selection unit for the second active rectifier voltage frequency converter and generating control signals of said switches of the rectifier is connected to a second control input of the high-frequency inverter.

The invention is illustrated by drawings, where:

- in FIG. 1 shows a functional diagram of a control device for a high voltage frequency converter;

- in FIG. 2 shows a functional diagram of a high voltage frequency converter;

- in FIG. 3 shows a diagram of a three-phase three-level active voltage rectifier;

- in FIG. 4 shows two planes, each of which contains twenty-four non-zero basic stress vectors, which are in a certain way combined into seven groups — a, b, c, a _p , a _n , b _p and b _n ;

- in FIG. 5 shows a plane containing 144 non-zero basic stress vectors, which are obtained by summing specially selected vectors depicted on the previously indicated two planes;

- in FIG. 6 shows a table with pre-selected basic voltage vectors for active voltage rectifiers, for various sectors and for two control ranges;

- in FIG. 7 shows a simplified equivalent circuit of the active voltage rectifier (a) and vector diagrams (b, c, d) explaining the dynamics of changes in the active and reactive currents of the active voltage rectifier;

- in FIG. 8 shows the characteristics of the relay regulators of active and reactive currents of an active voltage rectifier;

- in FIG. 9 and FIG. Figure 10 shows the oscillograms of the changes in the individual coordinates of the control device for a high-voltage frequency converter for five periods of supply voltage (a ... and), obtained on the basis of a mathematical model in the Matlab Simulink software environment.

The inventive control device of a high-voltage frequency converter (Fig. 1), contains a voltage sensor of the power source 1, the input of which is connected to the output of the three-phase power source 2, and the output to the voltage asymmetry calculation unit of the power source 3. The first output of the voltage asymmetry calculation unit is connected to the first the input of the control system of the frequency converter with a symmetrical voltage of the power source 4, and the second output with the voltage regulator of the DC link 5. The output of the voltage regulator is connected ene to a second input of said frequency converter control system. The first and second outputs of the specified control system 4 are connected respectively to the first and second control inputs of the high-voltage frequency converter 6, the power input of which is connected to a power source 2, and the power output to a synchronous machine 7. To the first information output of the high-voltage frequency converter via a current sensor 8 the power source is connected to the third input of the frequency converter control system. The fourth input of the specified control system is connected to the output of the voltage sensor of the power source 1, and the fifth input is connected to the output of the voltage sensor of the DC link 9. Three inputs of the specified voltage sensor 9 are connected to the second, third, and fourth information outputs of the high-voltage frequency converter. The sixth input of the control system of the frequency converter with a symmetrical voltage of the power source 4 is connected to the reactive current setter 10.

The control device (Fig. 1) is additionally equipped with a control system for a high-voltage frequency converter with asymmetric voltage of the power source 11. The control system includes a unit for calculating the active and reactive components of the currents 12 of the power source. The first input of the indicated unit is connected to the output of the current sensor of the power source 8, and the second input to the first output of the phase-locked loop of frequency 13 and the formation of the sector number on the third plane of the base vectors, the input of this unit is connected to the output of the voltage sensor of the power source 1. The first and second outputs the unit for calculating the active and reactive component currents are connected respectively to the first inputs of the relay controller of the active current 14 and the relay controller of the reactive current 15. The outputs of these relay controllers Hur connected respectively to first and second inputs of the block preselection base voltage vector 16 active high voltage rectifier inverter. The third input of the preliminary selection of the base voltage vector 16 is connected to the second output of the phase locked loop frequency 13 and the formation of the sector numbers on the third plane of the base vectors. In this case, the second input of the active current relay controller 14 is connected to the first output of the unit for calculating the set value of the active current and the state of the voltage balance on the capacitors 17 of the DC link of the high-voltage frequency converter. The first input of the specified calculation unit 17 is connected to the output of the voltage regulator of the DC link 5. In this case, the second input of the relay reactive current regulator 15 is connected to the output of the reactive current regulator 10. The first output of the preliminary selection of the base voltage vector 16 of the active rectifiers of the high-voltage frequency converter is connected to the first the input of the base voltage vector selection block 18 for the active voltage rectifier of the first frequency converter and the formation of control signals with the keys rectifier indicated. The second output of the preliminary selection of the base voltage vector 16 of the active rectifiers of the high-voltage frequency converter is connected to the first input of the selection of the base voltage vector 19 for the active voltage rectifier of the second frequency converter and generating control signals with the keys of the rectifier. The second inputs of these blocks 18, 19 select the basic voltage vector are connected to the second output of the unit for calculating the set value of the active current and the state of the voltage balance on the capacitors 17 of the DC link of the high-voltage frequency converter. The second input of the specified calculation unit 17 is connected to the output of the DC-link voltage sensor 9. The first output of the base voltage vector selection block 18 for the active voltage rectifier of the first frequency converter and generating control signals by the keys of the rectifier through the storage unit of its previous value of the base voltage vector 20 is connected to its third entrance. In this case, the second output of the base voltage vector selection block 18 for the active voltage rectifier of the first frequency converter and the formation of control signals by the keys of the specified rectifier is connected to the first control input of the high-voltage frequency converter 6. The first output of the base voltage vector selection block 19 for the active voltage rectifier of the second frequency converter and the formation of control signals with the keys of the specified rectifier through the storage unit of its previous value of the base voltage ctor 21 is connected to its third input. In this case, the second output of the base voltage vector selection block 19 for the active voltage rectifier of the second frequency converter and generating control signals with the keys of the specified rectifier is connected to the second control input of the high-voltage frequency converter 6.

The high-voltage frequency converter 6 (Fig. 2), as in the prototype, contains the first 22 and second 23 three-phase phase-shifting transformers, respectively, at 0 and +30 degrees. The primary winding of the first phase-shifting transformer 22 has six leads and is connected in series with the primary winding of the second phase-shifting transformer 23, which is connected to a star. In this case, the beginning of the primary winding of the first phase-shifting transformer 22 is connected to a power source 2. The secondary windings of these transformers are connected to a star and a triangle (Fig. 2) and connected to the first 24 and second 25 frequency converters, respectively. Each converter consists of a three-phase three-level active rectifier 26, a three-phase three-level voltage inverter 27 and a inductor 28. In this case, the same output terminals of the phases of the frequency converters are interconnected and connected to a synchronous machine 7. The inputs of the common for both frequency converters DC link 29 with zero point connected to the outputs of both active rectifiers 26, and the outputs of the specified DC link connected to the inputs of both voltage inverters 27.

Three-phase three-level active rectifier 26 (Fig. 3), as in the prototype, contains three phase racks 30, 31 and 32, the outputs of which are connected in parallel and connected to the DC link 29, which contains two series-connected capacitors 33 and 34. The first the capacitor 33 creates a positive potential in the phases of the inverter 27, and the second capacitor 34 creates a negative potential. The common point of the capacitors 35 is the neutral point of the three-phase three-level active rectifier 26 and creates a zero potential at the phases of the inverter 27. Each of the phase racks 30, 31 and 32 contains four fully connected keys 36, 37, 38 and 39 connected in series. To the connection point of the first 36 and a second 37 controlled keys in each phase rack connected to the cathode of the first diode 40, the anode of which is connected to the neutral point 35 of the active rectifier. The connection point of the second 37 and third 38 controlled keys is the power inputs of the active rectifier 26 in each phase rack. The anode of the second diode 41, the cathode of which is connected to the neutral point 35 of the active rectifier, is connected to the connection point of the third 38 and fourth 39 controlled keys in each phase rack. The power inputs of the first and second active rectifiers 26 are connected respectively to the secondary windings of the first 22 and second 23 phase-shifting transformers.

In the inventive device, a three-phase three-level active rectifier 26 is made on fully controllable keys 36 - 39 (Fig. 3) with a relay-vector control system for short-term asymmetrical voltage dips. The use of two three-phase phase-shifting transformers and a three-level active rectifier in powerful adjustable electric drives, for example, for rolling mills, improves the input current shape of the active rectifier at a relatively low switching frequency of its keys.

To variable-frequency electric drives of continuous technological facilities, for example, electric drives of rolling mills, high demands are placed on the reliability of their power supply. Since, uncontrolled shutdown of these drives reduces performance, and can also cause mechanical damage to expensive equipment. In the inventive device, thanks to the relay-vector key management system of the active rectifiers, a high-speed electric drive is provided and increased resistance to disturbances from the supply network.

At the same time, the structure of the switching table of the keys of active rectifiers is of great importance, providing a minimum number of switching and a satisfactory quality of transients. The adjustable values in the relay-vector control system of the claimed device are the active and reactive components of the currents of the power source, their regulation is carried out by rational selection of the base voltage vectors of the active rectifiers of the high-voltage frequency converter.

In FIG. 4, a plane is depicted, which is widely known and generally available in the sources devoted to this topic (see RF patent No. 168787). The specified plane contains twenty-four non-zero basic stress vectors, which are in a certain way combined into seven groups - a, b, c, a _p , a _n , b _p and b _n . The vectors are located on the borders of twelve thirty-degree sectors, which are numbered from 1.1 to 1.12. These vectors provide regulation of the input voltage of the active rectifier of the first frequency converter in the range from 0.5 to 1.0 of its nominal value. Near each of the twenty-four vectors (Fig. 4, a) there are three capital letters that indicate how, when choosing this vector, the corresponding inputs A, B and C of the active rectifier 26 (Fig. 3) of the first frequency converter 24 are connected to the link DC 29 frequency converter. For example, the designation P0N indicates that the input of phase A of the active rectifier 26 is connected to the positive potential (P) of the DC link 29 of the frequency converter, the input of phase B to its neutral point (0), and the input of phase C to its negative potential (N )

In FIG. 4b shows a second plane with similar base vectors a, b, c, a _p , a _n , b _p and b _n , which together with sectors 2.1 to 2.12 relative to their vectors of the same name in FIG. 4, and rotated 30 degrees counterclockwise. Vector on the second plane (Fig. 4, b) provide the input voltage of the active rectifier 26 of the second frequency converter 25 in the range from 0.5 to 1.0 of its nominal value. Three capital letters near each vector, as before, indicate how, when choosing this vector, the inputs of the active rectifier 26 of the second frequency converter 25 are connected to the DC link 29 of the frequency converter.

In FIG. 5 shows a third plane containing 144 non-zero basic stress vectors, which are obtained by summing specially selected vectors depicted on the first and second planes of the basic stress vectors (Fig. 4, a and 4, b). Note that the actual number of vectors that can be obtained from the summation results reaches 576 pieces, i.e. significantly more than shown in FIG. 5. Here we show specially selected vectors that provide the minimum number of key switches in each active rectifier, their uniform loading and high efficiency of each active rectifier and the entire converter as a whole. Next, the algorithm of the inventive device with these vectors will be described (Fig. 5), which can provide high-speed performance of the frequency converter, which is especially important for short-term asymmetric voltage dips in the supply network.

The inventive device also provides high reliability of the frequency converter and a satisfactory harmonic composition of its input currents.

The algorithm for generating basic stress vectors in FIG. 5 next.

The first step - each vector of the first plane (Fig. 4, a) is summed, with the vector of the second plane (Fig. 4, b), which has the same direction in the depicted coordinate system. For example, the vector “a” in FIG. 4a is added to the vector “c” in FIG. 4b, having the same direction.

градусов. Например, вектор «а» (фиг. 4,а) суммируется с векторами «a», «a_p» и «a_n» (фиг. 4,б), опережающие его на 30 градусов, и с векторами «b», «b_p» и «b_n», отстающие от него на 30 градусов. The second step - each vector of the first plane (Fig. 4, a) is summed, with the vector of the second plane, the direction of which differs from its direction by

degrees. For example, the vector "a" (Fig. 4, a) is summed with the vectors "a", "a _p " and "a _n " (Fig. 4, b), which are 30 degrees ahead of it, and with the vectors "b", “B _p ” and “b _n ” 30 degrees behind it.

As a result of summing the above vectors, we get seven vectors “ac”, “aa”, “aa _p ”, “aa _n ”, “ab”, “ab _p ” and “ab _n ”. However, in FIG. 5 shows five vectors “aa”, “ac”, “ab”, “aa _pn ”, and “ab _pn ”. Here, the notation “aa _pn ” means that actually at this place on the plane of the vectors are two vectors “aa _p ” and “aa _n ”, which have the same direction and equal moduli. The above “aa _pn ” record allows reducing the number of vectors displayed on the plane of FIG. 5, i.e., make the drawing less saturated with vectors. Similarly, the designation “ab _pn ” indicates that two vectors “ab _p ” and “ab _n ” are in this place. The same is true for the remaining entries in FIG. 5, including for records containing two vectors with two indices. For example, the designation “a _pn a _pn ” indicates that four vectors “a _p a _p ”, “a _p a _n ”, “a _n a _p ” and “a _n a _n ” are located on this plane.

Let us explain how the active rectifier 26 behaves (Fig. 3) when choosing the vector "a _p " or "a _n " (Fig. 4, a). Since both vectors occupy the same location on the plane of the vectors, therefore, they form the same linear voltage at the input of the active rectifier 26.

However, when choosing, for example, the “a _p ” vector, the upper capacitor 33 of the DC link 29 (Fig. 3) will be charged, and the lower 34 will be discharged, since, for example, three large letters P00 correspond to the “a _p ” vector (Fig. 4a), which means connecting the input A of the active rectifier 26 to the positive potential (P) of the DC link 29 and connecting the inputs B and C to its neutral point (0).

If you select the vector "a _n " (Fig. 4, a), then the capacitor 33 (Fig. 3) will be discharged, and the capacitor 34 will be charged, since the vector "a _n " corresponds to three large letters 0NN, which means connecting the input And the active rectifier 26 to the neutral point (0) of the DC link 29 and the connection of inputs B and C to its negative potential (N).

The described processes of charging and discharging capacitors 33 and 34 (Fig. 3) in the DC link 29 will hereinafter be used for their natural and forced balancing during operation of active rectifiers 26 of both frequency converters 24 and 25 (Fig. 2).

All of the above, i.e. the formation of the input voltage at the input of the active rectifier and the balancing of the capacitors 33 and 34 is also true for the vectors "b _p " and "b _n " (Fig. 4).

The third step - all vectors are distributed between three groups (Fig. 5), depending on the length of their modules: a group of short vectors, a group of medium vectors and a group of long vectors. Moreover, within each group, the modules of vectors should not differ significantly from each other. Modules of medium vectors are 1.41 and 1.5 more than modules of short vectors, and modules of long vectors are 1.93 and 2 times more than modules of short vectors. Explanations of why medium and long vectors are so many times different from short vectors will be given below.

The group of short vectors (Fig. 5) includes the vectors “a _pn a _pn ”, “b _pn a _pn ”, “b _pn b _pn ”, “a _pn b _pn ”. On the third plane of the base vectors 12 are depicted. However, as previously noted, the double index of the “a _pn ” vector indicates that in fact at the indicated location on the vector plane there are two vectors “a _p ” and “a _n ”. The designation of the vector “a _pn a _pn ” indicates that at the indicated location on the plane of the vectors there are four vectors “a _p a _p ”, “a _p a _n ”, “a _n a _p ” and “a _n a _n ”. Thus, in FIG. 5, the total number of short vectors is 48, and the modules of all vectors are equal. Note that the claimed control system of the frequency converter according to a certain algorithm determines which of the four short vectors occupying the same location is currently selected for the effective regulation of the input voltages of the active rectifiers 26 of the high-voltage frequency converter 6 (Fig. 2).

To the group of mean vectors in FIG. 5 refer to the vectors “a _pn a”, “ca _pn ”, “b _pn a”, etc. Each middle vector contains one of the following vectors “a”, “b” or “c” and one of two vectors “a _pn ” or “b _pn ” in different combinations. The number of such vectors (Fig. 5) is 36. However, given that each average vector contains one vector with a double index, the total number of average vectors will be 72. Note that among the average vectors there are 48 vectors whose modules have exactly 1 , 5 times larger than the moduli of short vectors. In addition, among the average vectors, there are 24 vectors whose modules differ 1.41 times from the modules of short vectors, i.e. they will be slightly shorter. The difference is 6%, accepts that this is a perfectly acceptable deviation. In FIG. Figure 5 shows that slightly shortened average vectors contain the vector "c", for example, "ca _pn ", "b _pn c", etc.

The group of long vectors (Fig. 5) includes the vectors “aa”, “ca”, “ba”, etc. The number of such vectors is 24. Moreover, the modules are 12 long vectors (“aa”, “ba”, “bb” and etc.) is 2 times larger than the modules of short vectors (“a _pn a _pn ”, “b _pn a _pn ”, etc.), and the modules of the other 12 vectors differ 1.93 times from the modules of short vectors i.e. a little shorter. The difference is 3, 5%, accepts that this is a perfectly acceptable deviation. In FIG. Figure 5 shows that the slightly shortened long vectors contain the vector “c”, for example, “ca”, “bc”, etc.

Note that among the selected vectors in FIG. 5, the “cc” vector is missing, although the angle between the “c” vectors in FIG. 4a and FIG. 4, b is equal to 30 degrees. The absence of the "cc" vector in FIG. 5 is due to the fact that its modulus exceeds the modulus of the average vector “a _pn a” by 15% and shorter than the modulus of the long vector “aa” by 13.4%. The indicated deviation of the modulus within the middle and long groups of vectors is considered unacceptable. Therefore, the vector "ss" is not involved in the regulation of the input voltages of the active rectifiers 26 of the high-voltage frequency converter 6 (Fig. 2).

Thus, out of 576 vectors that could be obtained by summing the vectors of the first and second base planes (Fig. 4, a, 4, b), 144 nonzero basic stress vectors were selected, divided into three groups: short - 48, medium - 72 and long ones - 24. Moreover, the long vectors “aa”, “ca”, “ba”, etc., divide the third plane into twenty-four fifteen-degree sectors, numbered (Fig. 5) with numbers from 3.1 to 3.24.

The inventive control system in the process of its operation at certain points in time selects one of 144 vectors. During the period of the supply voltage, the selected vectors effectively regulate the instantaneous input voltages of the active rectifiers 26 (Fig. 2) of the first 24 and second 25 frequency converters in the range from 0.5 to 1.0 of their nominal values. In this case, the selected vectors provide the minimum number of switchings of keys in each active rectifier, their uniform loading, high efficiency of each active rectifier and the entire converter 6 as a whole. In addition, high speed converter is achieved by using the above vectors (Fig. 5), which is especially important for short-term asymmetrical voltage dips. The inventive control system also provides high reliability of the frequency converter and a satisfactory harmonic composition of its input currents, due to the formation of instantaneous voltage values at the inputs of active rectifiers of such magnitude, shape and phase that the currents consumed from the network are almost sinusoidal.

We introduce the concept of “the first range of regulation”, when short and medium vectors are selected to form the input voltages of the active rectifiers 26 of the first 24 and second 25 frequency converters (ranging from 0.5 to 0.75 of their nominal values) (Fig. 5) . For example, for sector 3.1, the following vectors participate in the 1st regulation range: “a _pn a _pn ”, “b _pn a _pn ”, “aa _pn ” and “ca _pn ”.

We introduce the concept of “2nd regulation range” when medium and long vectors are selected to generate instantaneous input voltages of active rectifiers 26 of the first 24 and second 25 frequency converters (ranging from 0.75 to 1.0 of their nominal values) (Fig. 5 ) For example, for sector 3.1, the following vectors participate in the 2nd regulation range: “aa _pn ”, “ca _pn ”, “aa”, and “ca”. The concepts of the 1st and 2nd regulation ranges will be further used to describe the operation of the claimed device.

при несимметричном провале напряжения источника питания 2. Изображенный овал (фиг. 5) обусловлен следующей несимметрией: в фазе А провал составляет 40 %, а в фазах В и С провал отсутствует.In addition to 144 basic stress vectors and 24 sectors in FIG. 5 depicts an oval that displays the trajectory of the end of the network voltage vector

with an asymmetrical voltage dip of the power source 2. The depicted oval (Fig. 5) is due to the following asymmetry: in phase A, the dip is 40%, and in phases B and C there is no dip.

Note that two sections of the oval are located in those areas of some sectors where long and medium voltage vectors are used to regulate the input voltages of active rectifiers 26, i.e., in the 2nd regulation range. Such sectors (Fig. 5) can be considered sectors with numbers 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, as well as sectors with numbers 3.16, 3.17, 3.18, 3.19, 3.20 and 3.21.

Two more sections of the oval are located in those areas of some sectors where medium and short voltage vectors are used to control the input voltages of active rectifiers 26, i.e., in the first control range. Such sectors (Fig. 5) can be considered sectors with numbers 3.11, 3.12, 3.13, 3.14, as well as sectors with numbers 3.23, 3.24, 3.1 and 3.2.

In addition, the oval has two sections in which its path changes from the 1st regulation range to the 2nd regulation range, these are sectors 3.3 and 3.15, and two sections in which its path changes from the 2nd regulation range to 1- The second regulation range is sectors 3.10 and 3.22.

при несимметричном провале напряжения источника питания 2, учитывается в дальнейшем в алгоритме работы заявляемой системы.The described feature of the trajectory of the end of the network voltage vector

with an asymmetrical voltage dip of the power source 2, it is taken into account in the future in the algorithm of the inventive system.

Note that in the notation of vectors (Fig. 5), the first letter indicates a vector (see Fig. 4, a) that controls the pulse input voltage of the active rectifier 26 of the first frequency converter 24 (Fig. 2), and the second letter indicates the vector (Fig. 4, b) that controls the pulse input voltage of the active rectifier 26 of the second frequency converter 25 (Fig. 2). For example, the vector "ac" located on the border of sectors 3.23 and 3.24 (Fig. 5) indicates that in the first frequency converter 24 (Fig. 2) the regulation of the pulse input voltage of the active rectifier is carried out by the vector "a", and in the second frequency converter 25 vector "c".

In the normal mode of operation of the high-voltage frequency converter 6 (Fig. 2), the voltage of the power supply 2 is divided approximately equally between the first 22 and second 23 three-phase phase-shifting transformers. The role of buffer reactors, which are known to be an integral element of active voltage rectifiers, in the above circuit of the frequency converter 6 is played by the scattering inductance of the indicated transformers 22 and 23. Moreover, their transformation coefficients are selected so that both transformers 22 and 23 and both active rectifiers 26 were downloaded the same way.

It was previously noted that the first plane of the base voltage vectors (Fig. 4, a) allows you to generate instantaneous input voltages on the alternating current side of the active rectifier 26 of the first frequency converter 24 (Fig. 2). According to the principle of operation of an active voltage rectifier, the difference between the instantaneous values of the sinusoidal voltage of the supply network and the instantaneous input voltages at the AC terminals of the active rectifier is perceived by the buffer reactors. Due to the use of pulse width modulation mode, the instantaneous voltage value generated by the active rectifier on the AC side has a satisfactory harmonic composition, in which the fundamental and higher harmonics differ significantly in frequency and amplitude. This creates favorable conditions for filtering the higher harmonics of the current by buffer reactors and the formation of a practically sinusoidal current of the network.

) с заданным фазовым углом. Иными словами, можно обеспечить работу преобразователя частоты с заданным значением коэффициента мощности, например равным единице, что осуществляется в заявляемой системе управления.In addition, the phase angle of the rectifier current depends on the ratio of the amplitudes and phase angles of the voltages applied to the buffer reactors from the network side and from the side of the active rectifier, as well as from the parameters (inductance and active resistance) of the reactor. Varying, using the active rectifier control system, the parameters of the main harmonic of its alternating voltage at terminals A, B and C (Fig. 3), it is possible to ensure the consumption of the required current from the network (

) with a given phase angle. In other words, it is possible to ensure the operation of the frequency converter with a given value of the power factor, for example equal to unity, which is carried out in the inventive control system.

Thus, the first plane of the base voltage vectors (Fig. 4, a) allows you to generate instantaneous input voltage on the alternating current side of the active rectifier 26 (Fig. 2) of the first frequency converter 24. The role of the buffer reactor for the specified rectifier is the scattering inductance of the first transformer 22, and as the instantaneous values of the sinusoidal voltage of the supply network, the voltage on the primary windings of the specified transformer is used.

Similarly, the second plane of the base voltage vectors (Fig. 4, b) allows you to generate an instantaneous input voltage on the AC side of the active rectifier 26 (Fig. 2) of the second frequency converter 25. In this case, the scattering inductance of the second transformer 23 plays the role of a buffer reactor for the specified rectifier and, as the instantaneous values of the sinusoidal voltage of the supply network, the voltage on the primary windings of the specified transformer is used.

The third plane of the base voltage vectors (Fig. 5) allows you to generate a fictitious instantaneous input voltage on the AC side with the simultaneous operation of both active rectifiers 26 of the first 24 and second 25 frequency converters. At the same time, as in the classic active voltage rectifiers, the voltage of the power supply 2 is used as the instantaneous values of the sinusoidal voltage.

In reality, a dummy instantaneous input voltage does not exist, i.e. it is impossible to measure it with any device or see on the oscilloscope screen. However, its formation in the inventive device can significantly simplify the algorithm for generating control signals by active rectifiers 26 (Fig. 2) of the high-voltage frequency converter 6 with short-term asymmetrical voltage dips.

и электромагнитный момент двигателя

. (см. Виноградов А.Б. Векторное управление электроприводами переменного тока / ГОУВПО «Ивановский государственный энергетический университет имени В.И. Ленина». Иваново, 2008. 298 с.).In FIG. 6 shows a table with pre-selected basic voltage vectors for active voltage rectifiers 26 of the first 24 and second 25 frequency converters. The vectors in this table are uniquely associated with the corresponding vectors on the third plane of the vectors (Fig. 5). Such tables have been widely used in systems for direct control of engine torque, in which the stator flux linkage is adjustable

and electromagnetic torque of the engine

. (see Vinogradov A.B. Vector control of AC electric drives / GOUVPO "Ivanovo State Power Engineering University named after V.I. Lenin". Ivanovo, 2008. 298 p.).

и реактивная

составляющие пространственного вектора тока источника питания 2.In the inventive device adjustable coordinates are active

and reactive

components of the spatial current vector of the power source 2.

и реактивного

токов источника питания 2. При этом, как ранее отмечалось, выбранный вектор (фиг. 5) представляет собой комбинацию из двух векторов, где первый из них воздействует на активный выпрямитель 26 первого преобразователя частоты 24, а второй – на активный выпрямитель 26 второго преобразователя частоты 25. Например, для сектора 3.1 (фиг. 5) выбран вектор напряжения «са», расположенный на границе секторов 3.1 и 3.2. В таблице (фиг. 6) этот вектор расположен на пересечении строки с номером сектора 3.1 и третьим столбцом. При этом первый базовый вектор напряжения «с» формирует мгновенное входное напряжение на стороне переменного тока активного выпрямителя 26 первого преобразователя частоты 24, а второй базовый вектор напряжения «а» – мгновенное входное напряжение на стороне переменного тока активного выпрямителя 26 второго преобразователя частоты 25. Таким образом, совместное действие векторов «с» и «а» на соответствующих плоскостях фиг. 4,а и фиг. 4,б, т.е. вектора «са» на плоскости фиг. 5 осуществляют требуемое регулирование активного

и реактивного

токов источника питания 2.The first column of the table (Fig. 6) indicates the sector number (from 3.1 to 3.24) on the third plane of the base voltage vectors (Fig. 5), for which a base voltage vector is selected that performs the required regulation of the active

and jet

the current of the power source 2. Moreover, as previously noted, the selected vector (Fig. 5) is a combination of two vectors, where the first one acts on the active rectifier 26 of the first frequency converter 24, and the second on the active rectifier 26 of the second frequency converter 25. For example, for sector 3.1 (Fig. 5), the voltage vector "ca" is selected located at the boundary of sectors 3.1 and 3.2. In the table (Fig. 6), this vector is located at the intersection of the row with sector number 3.1 and the third column. In this case, the first base voltage vector "c" forms the instantaneous input voltage on the alternating current side of the active rectifier 26 of the first frequency converter 24, and the second basic voltage vector "a" forms the instantaneous input voltage on the alternating current side of the active rectifier 26 of the second frequency converter 25. Thus thus, the combined action of the vectors “c” and “a” on the corresponding planes of FIG. 4a and FIG. 4b, i.e. of the vector “ca” on the plane of FIG. 5 carry out the required regulation of active

and jet

power supply currents 2.

Note that in the 1st regulation range for the formation of instantaneous input voltages of the active rectifier 26 of the first 24 and second 25 frequency converters (ranging from 0.5 to 0.75 of their nominal values), groups of short basic vectors (columns with numbers 8 and 9) and groups of average basic vectors (columns with numbers 6 and 7).

In the 2nd regulation range for the formation of instantaneous input voltages of active rectifiers 26 of the first 24 and second 25 frequency converters (ranging from 0.75 to 1.0 of their nominal values), groups of average basic vectors (columns with numbers 4 and 5) and groups of long base vectors (columns with numbers 2 and 3).

и реактивного

токов источника питания 2. Let us explain how the required regulation of active

and jet

power supply currents 2.

- пространственный вектор напряжения источника питания,

- пространственный вектор напряжения на стороне переменного тока активного выпрямителя,

индуктивность буферного реактора,

пространственный вектор тока источника питания, он же - ток активного выпрямителя. Указанные вектора напряжений и тока представлены в неподвижной системе координат. Воспользуемся известным и общедоступным методом преобразования мгновенных значений напряжений и токов из неподвижной системы координат во вращающуюся систему координат dq (см. Шрейнер Р.Т. Математическое моделирование электроприводов переменного тока с полупроводниковыми преобразователями частоты. Екатеринбург. УРО РАН, 2000. 654 с.). Представление переменных в системе dq координат существенно упрощает анализ работы активного выпрямителя. Оси системы координат dq вращаются относительно неподвижных осей системы координат с угловой скоростью ω, определяемой частотой напряжения питающей сети. Примем, что ось d вращающейся системы координат dq (фиг. 7,б) ориентирована по вектору напряжения источника питания

. Тогда вектор напряжения сети

в этой системе координат будет представлен векторами напряжений

и

. Вектор напряжения на стороне переменного тока активного выпрямителя

- это один из векторов, изображенных на третьей плоскости векторов (фиг. 5). Во вращающейся системе координат dq вектор

будет представлен векторами напряжений

и

. Вектор тока источника питания

во вращающейся системе координат dq будет представлен векторами тока

и

, отображающие соответственно активную и реактивную составляющие тока источника питания

. Ранее отмечалось, что система управления активным выпрямителем поддерживает его коэффициент мощности практически равный единице, т.е. реактивная составляющая тока должна быть равна нулю

.In FIG. 7, a simplified equivalent circuit diagram of an active voltage rectifier is shown, where

- spatial voltage vector of the power source,

- spatial voltage vector on the alternating current side of the active rectifier,

buffer reactor inductance

the spatial vector of the current of the power source, it is also the current of the active rectifier. The indicated voltage and current vectors are presented in a fixed coordinate system. We use the well-known and generally accessible method of converting instantaneous voltage and current values from a fixed coordinate system to a rotating coordinate system dq (see Shreiner R.T. Mathematical modeling of AC electric drives with semiconductor frequency converters. Yekaterinburg. URO RAS, 2000. 654 pp.). The representation of variables in the dq coordinate system greatly simplifies the analysis of the operation of the active rectifier. The axes of the coordinate system dq rotate relative to the fixed axes of the coordinate system with an angular velocity ω determined by the frequency of the supply voltage. We assume that the axis d of the rotating coordinate system dq (Fig. 7, b) is oriented along the voltage vector of the power source

. Then the network voltage vector

in this coordinate system will be represented by stress vectors

and

. Voltage vector on the AC side of the active rectifier

- this is one of the vectors depicted on the third plane of the vectors (Fig. 5). In a rotating coordinate system dq vector

will be represented by stress vectors

and

. Power Supply Current Vector

in a rotating coordinate system, dq will be represented by current vectors

and

representing respectively the active and reactive components of the current of the power source

. It was previously noted that the control system of the active rectifier maintains its power factor almost equal to unity, i.e. the reactive component of the current must be zero

.

For a simplified equivalent circuit of an active voltage rectifier (Fig. 7, a), we write for the rotating coordinate system dq known and generally available equations (see Shreiner RT, Mathematical modeling of AC drives with semiconductor frequency converters. Yekaterinburg. URO RAS, 2000. 654 from.):

; (one) , (2)

оператор дифференцирования по времени;

и

слагаемые, учитывающие перекрестное влияние реактивного

и активного

токов на составляющие токов

и

. Предварительно примем, что эти влияния незначительные, тогда с учетов изложенного, что

, вышеприведенные уравнения (1) и (2) можно записать:Where

time differentiation operator;

and

cross-reactive terms

and active

currents for current components

and

. Preliminarily we assume that these influences are insignificant, then, taking into account the foregoing, that

, the above equations (1) and (2) can be written:

; (3)

. (four)

Let us analyze the obtained equations.

больше составляющей вектора напряжения на стороне переменного тока активного выпрямителя

, т.е. разность этих напряжений положительная

, то активная составляющая тока источника питания

будет увеличиваться. From equation (3) it follows if the network voltage vector

more component of the voltage vector on the alternating current side of the active rectifier

, i.e. the difference of these stresses is positive

, then the active component of the power supply current

will increase.

от его заданного значения не превысило допустимых пределов. The inventive device contains a relay controller of the active current 14 (Fig. 1), which controls that the current deviation

from its specified value did not exceed the permissible limits.

релейный регулятор 14 выдает команду на смену базового вектора напряжения

, составляющая

которого больше напряжения сети

, т.е.

, следовательно, ток

будет уменьшаться. Более подробно работа релейного регулятора активного тока 14 будет описана ниже.Upon reaching the current limit values

relay controller 14 issues a command to change the base voltage vector

component

which is greater than the mains voltage

, i.e.

therefore current

will decrease. In more detail, the operation of the relay controller of the active current 14 will be described below.

, т.е.

, то составляющая тока источника питания

будет уменьшаться. Если же

, т.е.

, то составляющая тока источника питания

будет увеличиваться.From equation (4) it follows if the component of the voltage vector on the alternating current side of the active rectifier

, i.e.

, then the current component of the power source

will decrease. If

, i.e.

, then the current component of the power source

will increase.

от его заданного значения не превысило допустимых пределов. Более подробно работа релейного регулятора реактивного тока 15 будет описана ниже.The inventive device contains a relay controller for reactive current 15 (Fig. 1), which controls that the deviation of the reactive current

from its specified value did not exceed the permissible limits. In more detail, the operation of the relay controller of the reactive current 15 will be described below.

, при этом активная составляющая тока уменьшается, т. е.

, (фиг. 7,б)

, при этом реактивная составляющая тока также уменьшается

. Общее количество возможных вариантов динамики изменения токов

и

равно четырем.In FIG. 7b shows one of the graphical interpretations of the above analysis when

, while the active component of the current decreases, i.e.

, (Fig. 7, b)

while the reactive component of the current also decreases

. The total number of possible options for the dynamics of current changes

and

equals four.

и

для сектора с номером 3.1 (фиг. 5) под воздействием четырех базовых векторов напряжений «аа», «са», «а_pnа_pn» и «b_pnа_pn». In FIG. 7c and FIG. 7d shows graphical interpretations of the reaction of the component currents

and

for sector number 3.1 (Fig. 5) under the influence of four basic stress vectors “aa”, “ca”, “a _pn a _pn ” and “b _pn a _pn ”.

Based on what we can draw the following conclusions.

. Описанная динамика тока

изображена в первой строке таблицы на фиг. 6 для столбцов с номерами 2, 3, 6 и 7.The first conclusion. The selection of long basic stress vectors (Fig. 5 and Fig. 7, c) in the 2nd regulation range ("aa", "ca", "ba", etc.) and medium vectors in the 1st regulation range ( “Aa _pn ”, “ca _pn ”, “b _pn a”, etc.) in all sectors causes a decrease in the active component of the current of the power source

. Described current dynamics

shown in the first row of the table in FIG. 6 for columns numbered 2, 3, 6, and 7.

. Описанная динамика тока

изображена в первой строке таблицы на фиг. 6 для столбцов с номерами 4, 5, 8 и 9.The second conclusion. The choice of the average basic voltage vectors (Fig. 5) in the 2nd regulation range ("aa _pn ", "ca _pn ", "b _pn a", etc.) and short vectors in the 1st regulation range ("a _pn a _pn ”,“ b _pn a _pn ”, etc.) in all sectors causes an increase in the active component of the power supply current

. Described current dynamics

shown in the first row of the table in FIG. 6 for columns 4, 5, 8, and 9.

We introduce the concept of a “lagging base voltage vector”. This is a vector located relative to the sector in question on the border with the previous sector, in the previous sector or on the border of the previous sector and the previous sector. For example, the lagging vectors (Fig. 5) for sector 3.1 are the vectors “aa”, “aa _pn ” and “a _pn a _pn ”.

We introduce the concept of “leading base voltage vector”. This is a vector located relative to the sector in question at the border with the subsequent sector or at the border of the subsequent and following sectors. For example, leading vectors for sector 3.1 (Fig. 5) are the vectors “ca”, “ca _pn ” and “b _pn a _pn ”.

. Описанная динамика тока

изображена во второй строке таблицы (фиг. 6) для столбцов с четными номерами 2, 4, 6 и 8.The third conclusion. The choice of lagging base voltage vectors (Fig. 5) in the 1st and 2nd control ranges ("aa", "aa _pn ", "a _pn a _pn ", etc.) for all sectors causes an increase in the reactive component of the current power source

. Described current dynamics

shown in the second row of the table (Fig. 6) for columns with even numbers 2, 4, 6 and 8.

. Описанная динамика тока

изображена во второй строке таблицы (фиг. 6) для столбцов с нечетными номерами 3, 5, 7 и 9.The fourth conclusion. The choice of leading basic voltage vectors (Fig. 5) in the 1st and 2nd control ranges (“ca”, “ca _pn ” and “b _pn a _pn ”, etc.) for all sectors causes a decrease in the reactive component of the source current power supply

. Described current dynamics

shown in the second row of the table (Fig. 6) for columns with odd numbers 3, 5, 7 and 9.

в уравнении (1), которым мы ранее пренебрегли при анализе динамики изменения активного тока

источника питания при перемещении вектора сети

в пределах сектора. В процентном отношении доля слагаемого

мала по сравнению со слагаемыми

и

, не более 5 % (фиг. 7,б). Обусловлено это тем, что реактивный ток

мал, так как заявляемая система управления стремится уменьшить его до нуля. Однако когда вектора

и

становятся соизмеримыми между собой, слагаемое

в уравнении (1) проявляет свое влияние. Это происходит при переходе из 1-го диапазона регулирования во 2-ой диапазон регулирования и наоборот, т.е. в районе границе диапазонов регулирования.Consider how the term affects

in equation (1), which we previously neglected when analyzing the dynamics of changes in the active current

power source when moving a network vector

within the sector. In percentage terms, the proportion of the term

small compared to the terms

and

, not more than 5% (Fig. 7, b). This is due to the fact that reactive current

small, since the claimed control system seeks to reduce it to zero. However when the vectors

and

become commensurate with each other, the term

in equation (1) exerts its influence. This occurs when moving from the 1st regulation range to the 2nd regulation range and vice versa, i.e. in the area of border regulation ranges.

изменяется незначительно (не более 5 %, см. овал на фиг. 5), а модуль вектора напряжения на стороне переменного тока активного выпрямителя

изменяется на 3,4 % (уменьшается или увеличивается) для выбранного базового вектора напряжения.It is known that, within a sector whose angle is 15 ^° , the module of the network voltage vector

varies slightly (not more than 5%, see the oval in Fig. 5), and the voltage vector module on the alternating current side of the active rectifier

changes by 3.4% (decreases or increases) for the selected base voltage vector.

в пределах сектора меняет свой знак, то это приводит к изменению динамики активного тока

. Например, до определенного углового положения вектора сети

в процессе его перемещения выполняется условие

, т.е.

, при этом активный ток

будет уменьшаться. После достижения определенного углового положения вектором сети

, когда

, т.е.

, активный ток

станет увеличиваться, и наоборот. С учетом изложенного следует, что изменение динамики активного тока

происходит при выполнении условия

, а не в результате команд, которые формирует релейный регулятор 15 (фиг. 1) при достижении активным током его граничных значений.If the algebraic sum of stresses

within the sector changes its sign, this leads to a change in the dynamics of the active current

. For example, up to a certain angular position of the network vector

in the process of moving it, the condition

, i.e.

while active current

will decrease. After reaching a certain angular position by the network vector

when

, i.e.

active current

will increase, and vice versa. Based on the foregoing, it follows that the change in the dynamics of the active current

occurs when the condition is met

, and not as a result of the commands that form the relay controller 15 (Fig. 1) when the active current reaches its boundary values.

в уравнении (1) не оказывает существенного влияния на динамику изменения активного тока

источника питания при перемещении вектора сети

в пределах сектора. Это влияние проявляется лишь при смене диапазонов регулирования 1-го на 2-ой и наоборот. При этом длительности положительной и отрицательной динамик изменения активного тока

существенно отличаются, особенно на границах переходов из 1-го во 2-ой диапазоны регулирования и наоборот. Thus, within the 1st and 2nd ranges of regulation, the term

in equation (1) does not significantly affect the dynamics of changes in the active current

power source when moving a network vector

within the sector. This effect manifests itself only when changing the ranges of regulation of the 1st to the 2nd and vice versa. In this case, the duration of the positive and negative speaker changes in the active current

significantly differ, especially at the borders of transitions from the 1st to the 2nd regulation ranges and vice versa.

In the future, the conclusion made will be confirmed by the results of mathematical modeling (oscillograms) of the claimed control system for a high-voltage frequency converter made in the Matlab / Simulink software environment.

в уравнении (2), которым мы ранее пренебрегли при анализе динамики изменения реактивного тока

источника питания при перемещении вектора напряжения сети

в пределах сектора. Ранее было отмечено, что в системе dq координат вектор напряжение сети

представлен векторами напряжений

и

, т.е. в уравнении (2) в его правой части присутствуют два слагаемых

и

. При этом слагаемое

может быть соизмеримым или превышать слагаемое

. Обусловлено это тем, что активный ток

значительно превышает реактивный ток

. При этом напряжение

(фиг 7,б) в пределах сектора изменяется в диапазоне от -25 % до +25 % напряжения сети

, при перемещении вектора

. Consider how the term affects

in equation (2), which we previously neglected when analyzing the dynamics of changes in reactive current

power source when moving the network voltage vector

within the sector. It was previously noted that in the dq coordinate system, the vector is the network voltage

represented by stress vectors

and

, i.e. in equation (2) on its right side there are two terms

and

. Moreover, the term

may be comparable or exceed the term

. This is due to the fact that the active current

significantly exceeds reactive current

. In this case, the voltage

(Fig. 7, b) within the sector varies in the range from -25% to +25% of the mains voltage

when moving a vector

.

в уравнении (2) всегда создает отрицательную динамику изменения реактивного тока

, при

, т.е. в двигательном режиме работы синхронной машины. Поэтому чтобы создать, например, такую же положительную динамику изменения реактивного тока

необходимо выполнить два следующих условия

и

. Выполнение первого условия

обеспечивают отстающие базовые вектора напряжений (см. ранее сделанный третий вывод). Выполнить второе условие

возможно, но не в зоне границ переходов из 1-го во 2-ой диапазон регулирования и наоборот. В указанных зонах, даже при выбранных отстающих базовых векторах напряжений, второе условие не выполняется, так как напряжение

. При этом отклонение реактивного тока

в течение некоторого времени может значительно превышать допустимые значения. Note that the term

in equation (2) always creates a negative dynamics of the reactive current

at

, i.e. in the motor mode of operation of a synchronous machine. Therefore, in order to create, for example, the same positive dynamics of the reactive current

the following two conditions must be met

and

. Fulfillment of the first condition

provide lagging base stress vectors (see the previous third conclusion). Fulfill the second condition

perhaps, but not in the zone of the boundaries of transitions from the 1st to the 2nd regulation range and vice versa. In these zones, even with selected lagging base stress vectors, the second condition is not satisfied, since the voltage

. In this case, the deviation of the reactive current

for some time can significantly exceed the permissible values.

. Это позволило увеличить слагаемого

до 36 % и значительно снизить отклонение реактивного тока

на границах переходов.In the mathematical model of the inventive device for a high-voltage frequency converter (in a Matlab / Simulink environment), in order to approach the fulfillment of the second condition (for a nominal reference current of 1250 A), an additional rotation of the axes dq of coordinates was made at an angle of 6 ^° in the direction of rotation of the network voltage vector

. This allowed to increase the term

up to 36% and significantly reduce reactive current deviation

at the borders of transitions.

In the future, the conclusion made will be confirmed by the results of mathematical modeling (oscillograms) of the claimed control system for a high-voltage frequency converter, made in the Matlab / Simulink software environment.

.Note the peculiarity of the effects of the average basic stress vectors on the dynamics of the active current

.

), активная составляющая тока

уменьшается от действий средних векторов. В таблице (фиг. 6) это отображено в первой строчке

для столбцов с номерами 6 и 7. When the middle vectors together with the short vectors (Fig. 5) participate in the formation of the instantaneous input voltages of the active rectifiers for the 1st regulation range (

), the active component of the current

decreases from the action of medium vectors. In the table (Fig. 6) this is displayed in the first line

for columns numbered 6 and 7.

), активная составляющая тока

увеличивается от действий средних векторов. В таблице (фиг. 6) это отображено в первой строчке

для столбцов с номерами 4, 5.When the middle vectors together with the long vectors (Fig. 5) participate in the formation of instantaneous input voltages of the active rectifiers for the 2nd regulation range (

), the active component of the current

increases from the action of medium vectors. In the table (Fig. 6) this is displayed in the first line

for columns with numbers 4, 5.

We describe the purpose and operation of the blocks in the control system 11 (Fig. 1) by a high-voltage frequency converter with an asymmetric voltage of the power supply 2 in the inventive device.

и реактивной

составляющих токов источника питания 2 осуществляет преобразование мгновенных значений его токов из неподвижной системы координат во вращающуюся систему координат dq. Block calculation 12 (figure 1) active

and reactive

component currents of the power source 2 converts the instantaneous values of its currents from a fixed coordinate system to a rotating coordinate system dq.

Block 13 phase-locked loop frequency and the formation of the sector numbers on the third plane of the base vectors of the instantaneous voltage values of the power source 2 calculates two coordinates.

на третьей плоскости базовых векторов. Сигнал, указывающий угловое положение вектора напряжения формируется на первом выходе блока 13 и подается на второй вход блока вычисления 12 активной

и реактивной

составляющих токов источника питания 2. The first coordinate is the angular position of the spatial voltage vector of the power source

on the third plane of the base vectors. A signal indicating the angular position of the voltage vector is generated at the first output of block 13 and is fed to the second input of the calculation unit 12 active

and reactive

component currents of the power supply 2.

The second coordinate is the sector number on the third plane of the base vectors. A signal indicating the sector number is generated at the second output of block 13 and is supplied to the third input of block 16 for preliminary selection of the base voltage vector of the active rectifiers of the high-voltage frequency converter.

The control system 11 of the high-voltage frequency converter with an asymmetrical voltage of the power source 2 in the inventive device (Fig. 1) can be performed on the basis of a specialized microcontroller having peripheral devices, a processor, RAM and ROM.

сравнивает заданное значение активного тока (

) источника питания 2 и его текущее значение тока (

). По результатам сравнения формируется команда

(фиг. 8) для активных выпрямителей 26 (фиг. 2) на увеличение или уменьшение текущего активного тока

источника питания 2 в 1-ом или 2-ом диапазонах регулирования. Двухпозиционный релейный регулятор 15 реактивного тока

сравнивает заданное значение тока

и текущее значение тока

. По результатам сравнения формируется команда

(фиг. 8) для активных выпрямителей 26 на увеличение или уменьшение текущего реактивного тока

источника питания 2.Three-position relay controller 14 (Fig. 1) active current

compares the set value of the active current (

) power supply 2 and its current current value (

) Based on the results of the comparison, a team is formed

(Fig. 8) for active rectifiers 26 (Fig. 2) to increase or decrease the current active current

power supply 2 in the 1st or 2nd regulation ranges. On-off relay controller 15 reactive current

compares the set current value

and current value of current

. Based on the results of the comparison, a team is formed

(Fig. 8) for active rectifiers 26 to increase or decrease the current reactive current

power supply 2.

Note the features of the three-position relay controller 14.

источника питания 2 в 1-ом или 2-ом диапазонах регулирования.Its structural scheme contains (Fig. 8, a) a subtraction block 42, the first 43 and second 44 two-position relay controllers, a selection block 45 of one of the three groups of vectors, which increases or decreases the current value of the active current

power supply 2 in the 1st or 2nd regulation ranges.

, который подается на входы первого 43 и второго 44 релейных регуляторов (фиг. 8,а). Выходные команды регуляторов

и

подаются на входы блока выбора группы векторов 45, который выполняет функцию арифметического суммирования. На выходе последнего формируются одна из трех команд. Первая команда

- «выбрать группу коротких векторов», которая будет увеличить текущее значение активного тока

(см. фиг. 6). Вторая команда

- «выбрать группу средних векторов», которая будет уменьшать ток

в 1-ом диапазоне регулирования или увеличивать его во 2-ом диапазоне регулирования. Третья команда

- «выбрать группу длинных векторов», которая будет уменьшать текущее значение активного тока

.At the output of the subtraction unit 42, a mismatch signal is generated

, which is fed to the inputs of the first 43 and second 44 relay controllers (Fig. 8, a). Regulator Output Commands

and

fed to the inputs of the block selection group of vectors 45, which performs the function of arithmetic summation. At the output of the latter one of the three teams is formed. First team

- “select a group of short vectors”, which will increase the current value of the active current

(see Fig. 6). Second team

- “choose a group of medium vectors”, which will reduce the current

in the 1st regulation range or increase it in the 2nd regulation range. Third team

- “select a group of long vectors”, which will reduce the current value of the active current

.

- «работать в 1-ом диапазоне регулирования» или

- «работать во 2-ом диапазоне регулирования» (фиг. 8,а и 8,б; фиг. 6). При этом порог перехода из 1-го диапазона регулирования во 2-ой диапазон регулирования наступает при выполнении условия

, а порог перехода из 2-го диапазона регулирования в 1-ый диапазон регулирования наступает при выполнении условия

. Здесь

– зона гистерезиса второго релейного регулятора 44 (рис. 8,а).The first relay controller 43 generates at its output one of two commands

- "work in the 1st regulation range" or

- "work in the 2nd range of regulation" (Fig. 8, a and 8, b; Fig. 6). In this case, the transition threshold from the 1st regulation range to the 2nd regulation range occurs when the condition

, and the transition threshold from the 2nd regulation range to the 1st regulation range occurs when the condition

. Here

- hysteresis zone of the second relay controller 44 (Fig. 8, a).

- «увеличить текущее значение активного тока

источника питания 2» или

- «уменьшить текущее значение активного тока

источника питания 2». При этом порог перехода от команды

к команде

наступает при выполнении условия

, а порог перехода от команды

к команде

наступает при выполнении условия

.The second relay controller 44 generates at its output one of two commands

- “increase the current value of the active current

power supply 2 "or

- “reduce the current value of the active current

power supply 2 ". At the same time, the transition threshold from the team

to the team

occurs when the condition is met

, and the transition threshold from the team

to the team

occurs when the condition is met

.

меньше заданного значения

, а их разница

, то на выходе первого релейного регулятора 43 (фиг. 8,а) формируется команда

- «работать в 1-ом диапазоне регулирования». При этом на выходе второго релейного регулятора 44 формируется команда

- «увеличить текущее значение тока

источника питания 2». Под действием указанных команд

и

на выходе блока 45 формируется команда

- «выбрать вектор из группы коротких векторов

и увеличить текущее значение активного тока

» (фиг.8,б). Например, для сектора 3.1 (фиг. 5; фиг.6) команды

и

можно выполнить, выбирая вектор «a_pna_pn» или «b_pna_pn», т.е. один из коротких векторов. Ранее был сделан вывод, что выбор коротких векторов, которые расположены в столбцах 8 и 9 таблицы на фиг. 6, вызывает увеличение активной составляющей тока

источника питания 2. For example, if the current value of the active current

less than the set value

, and their difference

, then at the output of the first relay controller 43 (Fig. 8, a) a command is formed

- "work in the 1st regulation range." In this case, at the output of the second relay controller 44, a command is generated

- “increase the current current value

power supply 2 ". Under the action of these commands

and

at the output of block 45, a command is formed

- “select a vector from the group of short vectors

and increase the current value of the active current

"(Fig.8, b). For example, for sector 3.1 (FIG. 5; FIG. 6), the commands

and

can be performed by choosing the vector “a _pn a _pn ” or “b _pn a _pn ”, i.e. one of the short vectors. It was previously concluded that the selection of short vectors that are located in columns 8 and 9 of the table in FIG. 6, causes an increase in the active component of the current

power supply 2.

текущее значение активного тока

увеличивается. Однако когда достигается условие, что

, на выходе релейного регулятора 44 формируется команда

- «уменьшить текущее значение тока

», а на выходе блока 45

- «выбрать вектор из группы средних векторов» (фиг. 8), при этом

. Например, для сектора 3.1 (фиг. 5, фиг. 6) команды

,

и

можно выполнить, выбирая вектор «aa_pn» или «сa_pn», т.е. один из средних векторов. Ранее был сделан вывод, что в 1-ом диапазоне регулирования выбор средних векторов, которые расположены в столбцах 6 и 7 таблицы (фиг. 6) вызывает уменьшение активной составляющей тока

источника питания 2. Thus, under the command

current value of active current

increases. However, when the condition is reached that

, at the output of the relay controller 44 a command is generated

- “reduce the current current value

", And at the output of block 45

- "select a vector from the group of average vectors" (Fig. 8), while

. For example, for sector 3.1 (FIG. 5, FIG. 6), commands

,

and

can be performed by choosing the vector “aa _pn ” or “ca _pn ”, i.e. one of the middle vectors. It was previously concluded that in the 1st regulation range, the choice of average vectors that are located in columns 6 and 7 of the table (Fig. 6) causes a decrease in the active component of the current

power supply 2.

текущее значение активного тока

уменьшается. Когда достигается условие, что

, на выходе релейного регулятора 44 формируется команда

- «увеличить текущее значение тока

», а на выходе блока 45

формируется команда - «выбрать вектор из группы коротких векторов» (фиг. 8). При этом

. Таким образом, по командам

,

и

как и ранее выбираются короткие вектора. Under the command

current value of active current

decreases. When the condition is reached that

, at the output of the relay controller 44 a command is generated

- “increase the current current value

", And at the output of block 45

the team is formed - "select a vector from the group of short vectors" (Fig. 8). Wherein

. Thus, by commands

,

and

as previously selected short vectors.

находится в пределах 1-го диапазона регулирования. При этом выбранные базовые вектора напряжений (короткие и средние) фиг. 5 поддерживают значение текущего активного тока

в пределах допустимых отклонений

от заданного значения

в 1-ом диапазоне регулирования (фиг. 8,б). The described process will be repeated until the network voltage vector

is within the 1st regulation range. In this case, the selected basic stress vectors (short and medium) of FIG. 5 support the value of the current active current

within tolerance

from the set value

in the 1st range of regulation (Fig. 8, b).

, когда конец пространственного вектора

, перемещаясь по секторам (фиг. 5) описал овал, будут выбраны короткие и средние вектора, расположенные в секторах с номерами 3.23, 3.24, 3.1, 3.2, а также в секторах с номерами 3.11, 3.12, 3.13 и 3.14.For example, for unbalanced mains voltage

when the end of the spatial vector

moving along the sectors (Fig. 5) described the oval, short and medium vectors located in sectors with numbers 3.23, 3.24, 3.1, 3.2, and also in sectors with numbers 3.11, 3.12, 3.13 and 3.14 will be selected.

пересекает границу 1-го и 2-го диапазонов регулирования (фиг. 5), то динамика изменения текущего значения активного тока

автоматически станет положительной

, даже при выбранных средних векторах

, которые в 1-ом диапазоне регулирования делали динамику изменения тока

отрицательной

. На фиг. 5 это происходит в секторах с номерами 3.3 и 3.15.If the network voltage vector

crosses the border of the 1st and 2nd regulation ranges (Fig. 5), then the dynamics of changes in the current value of the active current

will automatically become positive

, even with selected average vectors

which in the 1st regulation range made the dynamics of current change

negative

. In FIG. 5 this happens in sectors with numbers 3.3 and 3.15.

больше длины проекции среднего вектора напряжения

на ось

(фиг. 7,б). Тогда из уравнения (3) следует, что отрицательная динамика изменения активного тока

в 1-ом диапазоне регулирования от действия средних векторов напряжений

(фиг. 8,б) меняется на положительную динамику изменения активного тока

во 2-ом диапазоне регулирования.This is due to the fact that in the second range of regulation the module of the network voltage vector

longer than the projection length of the average voltage vector

on the axis

(Fig. 7, b). Then from equation (3) it follows that the negative dynamics of changes in the active current

in the 1st range of regulation from the action of medium voltage vectors

(Fig. 8, b) changes to the positive dynamics of the active current

in the 2nd range of regulation.

уменьшается. При выполнении условия

на выходе первого релейного регулятора 43 (фиг. 8,а) формируется команда

- «работать во 2-ом диапазоне регулирования». На выходе второго релейного регулятора 44 сохраняется команда

- «уменьшить текущее значение тока

источника питания 2», так как

. Под действием указанных команд

и

на выходе блока 45 формируется команда

- «выбрать вектор из группы длинных векторов

и уменьшить текущее значение активного тока

» (фиг. 8,б). Для сектора 3.1 (фиг. 5, фиг.6) команды

и

можно выполнить, выбирая вектор «aa» или «сa», т.е. один из длинных векторов. Ранее был сделан вывод, что выбор длинных векторов, которые расположены в столбцах 2 и 3 таблицы (фиг. 6), вызывает уменьшение активной составляющей тока

источника питания 2. In view of the foregoing, it follows that the difference in currents

decreases. When the condition is met

at the output of the first relay controller 43 (Fig. 8, a) a command is formed

- "work in the 2nd regulation range." The output of the second relay controller 44 stores the command

- “reduce the current current value

power supply 2 ", as

. Under the action of these commands

and

at the output of block 45, a command is formed

- “select a vector from a group of long vectors

and reduce the current value of the active current

"(Fig. 8, b). For sector 3.1 (Fig. 5, 6) teams

and

can be done by choosing the vector “aa” or “ca”, i.e. one of the long vectors. It was previously concluded that the selection of long vectors that are located in columns 2 and 3 of the table (Fig. 6) causes a decrease in the active component of the current

power supply 2.

текущее значение активного тока

уменьшается. Когда достигается условие, что

, на выходе релейного регулятора 44 формируется команда

- «увеличить текущее значение тока

», а на выходе блока 45

- «выбрать вектор из группы средних векторов» (фиг. 8), при этом

. Например, для сектора 3.1 (фиг. 5, фиг.6) команды

,

и

можно выполнить, выбирая вектор «aa_pn» или «сa_pn», т.е. один из средних векторов. Ранее был сделан вывод, что выбор средних векторов, которые расположены в столбцах 4 и 5 таблицы (фиг. 6), вызывает увеличение активной составляющей тока

источника питания 2.Thus, under the command

current value of active current

decreases. When the condition is reached that

, at the output of the relay controller 44 a command is generated

- “increase the current current value

", And at the output of block 45

- "select a vector from the group of average vectors" (Fig. 8), while

. For example, for sector 3.1 (FIG. 5, FIG. 6), commands

,

and

can be performed by choosing the vector “aa _pn ” or “ca _pn ”, i.e. one of the middle vectors. It was previously concluded that the choice of average vectors that are located in columns 4 and 5 of the table (Fig. 6) causes an increase in the active component of the current

power supply 2.

текущее значение активного тока

увеличивается. Когда достигается условие, что

, на выходе релейного регулятора 44 формируется команда

- «уменьшить текущее значение тока

», а на выходе блока 45

- «выбрать вектор из группы длинных векторов» (фиг. 8). При этом

. Таким образом, по командам

,

и

как и ранее выбираются длинные вектора.Under the command

current value of active current

increases. When the condition is reached that

, at the output of the relay controller 44 a command is generated

- “reduce the current current value

", And at the output of block 45

- "select a vector from the group of long vectors" (Fig. 8). Wherein

. Thus, by commands

,

and

as before, long vectors are selected.

находится в пределах 2-го диапазона регулирования. При этом выбранные базовые вектора напряжений (длинные и средние) (фиг. 5) поддерживают значение текущего активного тока

в пределах допустимых отклонений

от заданного значения

во 2-ом диапазоне регулирования (фиг. 8,б).The described process will be repeated until the network voltage vector

is within the 2nd regulation range. In this case, the selected base voltage vectors (long and medium) (Fig. 5) support the value of the current active current

within tolerance

from the set value

in the 2nd regulation range (Fig. 8, b).

, когда конец пространственного вектора, перемещаясь по секторам (фиг. 5) описал овал, будут выбраны средние и длинные вектора, расположенные в секторах с номерами 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, а также в секторах с номерами 3.16, 3.17, 3.18, 3.19, 3.20 и 3.21.For the previously indicated unbalanced mains voltage

when the end of the spatial vector, moving through the sectors (Fig. 5) described the oval, medium and long vectors located in sectors with numbers 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, and also in sectors with numbers 3.16, 3.17 will be selected , 3.18, 3.19, 3.20 and 3.21.

пересекает границу 2-го и 1-го диапазонов регулирования, то динамика изменения текущего значения активного тока

автоматически станет отрицательной

, даже при выбранных средних векторах

, которые во 2-ом диапазоне регулирования делают динамику изменения тока

положительной

. На фиг. 5 это происходит в секторах с номерами 3.10 и 3.22.If the network voltage vector

crosses the border of the 2nd and 1st regulation ranges, then the dynamics of changes in the current value of the active current

will automatically become negative

, even with selected average vectors

which in the 2nd regulation range make the dynamics of current change

positive

. In FIG. 5 this happens in sectors with numbers 3.10 and 3.22.

меньше длины проекции среднего вектора напряжения

на ось

(фиг. 7,б). Тогда из уравнения (3) следует, что положительная динамика изменения активного тока

во 2-ом диапазоне регулирования от действия средних векторов напряжений

(фиг. 8,б) меняется на отрицательную динамику изменения активного тока

в 1-ом диапазоне регулирования.This is due to the fact that in the first control range, the module of the network voltage vector

less than the projection length of the average voltage vector

on the axis

(Fig. 7, b). Then from equation (3) it follows that the positive dynamics of the active current

in the 2nd range of regulation from the action of medium voltage vectors

(Fig. 8, b) changes to the negative dynamics of the active current

in the 1st regulation range.

увеличивается. При выполнении условия

на выходе первого релейного регулятора 43 формируется команда

- «работать в 1-ом диапазоне регулирования». На выходе второго релейного регулятора 44 сохраняется команда

- «увеличить текущее значение тока

источника питания 2», так как

. Под действием указанных команд

и

на выходе блока 45 формируется команда

- «выбрать вектор из группы коротких векторов

и увеличить текущее значение активного тока

» (фиг.8,б). Для сектора 3.1 (фиг. 5, фиг.6) команды

и

можно выполнить, выбирая вектор «a_pna_pn» или «b_pna_pn», т.е. один из коротких векторов. In view of the foregoing, it follows that the difference in currents

increases. When the condition is met

at the output of the first relay controller 43, a command is generated

- "work in the 1st regulation range." The output of the second relay controller 44 stores the command

- “increase the current current value

power supply 2 ", as

. Under the action of these commands

and

at the output of block 45, a command is formed

- “select a vector from the group of short vectors

and increase the current value of the active current

"(Fig.8, b). For sector 3.1 (Fig. 5, 6) teams

and

can be performed by choosing the vector “a _pn a _pn ” or “b _pn a _pn ”, i.e. one of the short vectors.

из 1-го во 2-ой диапазоны регулирования и наоборот описана полностью.Thus, the operation of the three-position relay controller 14 in the 1st and 2nd regulation ranges, as well as its operation during transitions of the mains voltage vector

from 1st to 2nd regulation ranges and vice versa is fully described.

Consider the operation of the relay controller 15 within the 1st range of regulation of the input voltages of the active rectifiers 26 (Fig. 8, c).

. При этом текущее значение реактивного тока

должно удовлетворять условию

, т.е. ток

должен находиться в пределах зоны гистерезиса

релейного регулятора 15 (фиг 8,в).It was previously noted that to ensure a unit value of the power factor of the active rectifier, it is necessary that the set value of the reactive current be zero

. In this case, the current value of the reactive current

must satisfy the condition

, i.e. current

must be within the hysteresis zone

relay controller 15 (FIG. 8, c).

, то для возвращения значения реактивного тока в пределы зоны гистерезиса на выходе релейного регулятора 15 формируется команда

- «увеличить текущее значение тока

источника питания 2». Например, для сектора 3.1 (фиг. 5, фиг.6) команду

можно выполнить, выбирая вектор «a_pna_pn» или ««aa_pn»», т.е. один из отстающих векторов. Ранее был сделан вывод, что выбор отстающих векторов, которые расположены в столбцах 6 и 8 таблицы (фиг. 6), вызывает увеличение реактивной составляющей тока

источника питания 2.If the condition is satisfied that

, then to return the value of the reactive current within the hysteresis zone at the output of the relay controller 15, a command is generated

- “increase the current current value

power supply 2 ". For example, for sector 3.1 (FIG. 5, FIG. 6), the command

can be performed by choosing the vector “a _pn a _pn ” or ““ aa _pn ””, i.e. one of the lagging vectors. It was previously concluded that the choice of lagging vectors, which are located in columns 6 and 8 of the table (Fig. 6), causes an increase in the reactive component of the current

power supply 2.

, то для возвращения значения реактивного тока в пределы зоны гистерезиса на выходе релейного регулятора 15 формируется команда

- «уменьшить текущее значение тока

источника питания 2». Например, для сектора 3.1 (фиг. 5, фиг.6) команду

можно выполнить, выбирая вектор «b_pna_pn» или ««ca_pn»», т.е. один из опережающих векторов. Ранее был сделан вывод, что выбор опережающих векторов, которые расположены в столбцах 7 и 9 таблицы (фиг. 6), вызывает уменьшение реактивной составляющей тока

источника питания 2.If the condition is satisfied that

, then to return the value of the reactive current within the hysteresis zone at the output of the relay controller 15, a command is generated

- “reduce the current current value

power supply 2 ". For example, for sector 3.1 (FIG. 5, FIG. 6), the command

can be performed by selecting the vector “b _pn a _pn ” or “ca _pn ”, i.e. one of the leading vectors. It was previously concluded that the choice of leading vectors, which are located in columns 7 and 9 of the table (Fig. 6), causes a decrease in the reactive component of the current

power supply 2.

, т.е. текущий реактивный ток

находится в пределах допустимого отклонения от заданного тока

, на выходе релейного регулятора 15 сохраняет свое действие последняя принятая команда

.If a

, i.e. current reactive current

is within the permissible deviation from the set current

, at the output of the relay controller 15, the last received command

.

According to the described algorithm, the relay controller 15 operates and within the 2nd range of regulation of the input voltages of the active rectifiers 26.

- «уменьшить текущее значение тока

источника питания 2» в таблице (фиг. 6) можно выполнить, выбирая вектора в столбцах 3 и 5. Ранее отмечалось, что в этих столбцах расположены опережающие вектора. Команду

- «увеличить текущее значение тока

источника питания 2» можно выполнить, выбирая в таблице вектора в столбцах 2 и 4 (фиг. 6). Ранее отмечалось, что в этих столбцах расположены отстающие вектора.In this case, the team

- “reduce the current current value

power supply 2 "in the table (Fig. 6) can be performed by selecting the vectors in columns 3 and 5. It was previously noted that leading vectors are located in these columns. The team

- “increase the current current value

power supply 2 "can be performed by selecting in the table the vectors in columns 2 and 4 (Fig. 6). It was previously noted that lagging vectors are located in these columns.

The preliminary selection block of the base voltage vector 16 (Fig. 1) for active rectifiers 26 (Fig. 2) of the high-voltage frequency converter 6 operates in accordance with the table (Fig. 6). It was previously mentioned that such tables were widely used in the method of direct control of the torque of AC motors. These tables are also called switching tables of basic voltage vectors, since they indicate which vectors should be selected for effective control of both voltage inverters and active voltage rectifiers in high-voltage frequency converters. The term "effective management of these devices" implies a choice of basic voltage vectors that increase the speed of devices and their efficiency.

» и «

» с выходов релейных регуляторов 14 и 15. Ранее было описано, что указанные команды выбирают один из столбцов в таблице (фиг. 6) в одной из трех групп векторов: длинные вектора (столбцы с номерами 2, 3); средние вектора (столбцы с номерами 4…7); короткие вектора (столбцы с номерами 8, 9). The first and second inputs of block 16 (Fig. 1) are given the command "

"And"

"From the outputs of the relay controllers 14 and 15. It was previously described that these commands select one of the columns in the table (Fig. 6) in one of three groups of vectors: long vectors (columns with numbers 2, 3); medium vectors (columns with numbers 4 ... 7); short vectors (columns with numbers 8, 9).

A signal from the second output of block 13, which indicates the line number in the table in FIG. 6.

The selected column and row in the table (Fig. 6) indicate the preliminary base stress vector, which occupies a certain position on the third plane of the base vectors (Fig. 5). It was previously noted that the vectors (Fig. 5) were obtained by summing in a special way selected vectors (Fig. 4a, Fig. 4b).

Based on the foregoing, a command is generated at the first output of block 16, which preliminary indicates which basic voltage vector should be selected in FIG. 4 a. The specified command is fed to the first input of the base voltage vector selection block 18 for the active rectifier 26 of the first frequency converter 24 and generating control signals with the keys of the specified rectifier. At the same time, a command from the second output of the calculation unit 17 is sent to the second input of block 18. This command indicates whether or not forced balancing of the capacitors 33, 34 (Fig. 3) is needed in the DC link 29. If forced balancing of the capacitors is needed (previously, more on this in detail) was described), then from the short vectors a _pn (b _pn ) the vector a _p or a _n (b _p or b _n ) is selected, which performs this balancing. At the same time, a signal from the output of block 20 is supplied to the third input of block 18 (FIG. 1). This signal indicates which basic voltage vector was selected in the previous step of selecting vectors in the first vector plane in FIG. 4 a.

Block 18 on the received three commands makes the final selection of the base voltage vector for efficient control of the active voltage rectifier 26 of the first frequency converter 24. In this case, the selected base voltage vector is generated at the first output of block 18 and then stored in block 20.

It should be noted that during the final selection of the basic voltage vector in block 18, it is necessary to fulfill the following requirements: to ensure the minimum number of key switches in the active voltage rectifier 26 (high speed), and if it is necessary to perform forced voltage balancing on the capacitors 33 and 34 in the DC link 29.

The fulfillment of these requirements is described in detail by the authors in the patent for invention No. 2662151. In the indicated device, minimization of the number of switching switches and forced balancing of the voltage across the capacitors are carried out to control a three-phase three-level voltage inverter. Since the power circuit of an active voltage rectifier is similar to that of a voltage inverter, the claimed device does not describe how to fulfill these requirements.

At the second output of block 18, control signals are generated by the keys of the active rectifier 26 of the first frequency converter 24 (Fig. 2). The algorithm for generating control signals is also described in detail in the aforementioned patent for invention No. 2662151, therefore, it is not provided in the claimed device.

A command is generated at the second output of block 16, which previously indicates which basic voltage vector should be selected in FIG. 4, b. The specified command is fed to the first input of block 19 (Fig. 1) of selecting the base voltage vector for the active rectifier 26 of the second frequency converter 25 and generating control signals with the keys of the specified rectifier. At the same time, a command from the second output of the calculation unit 17 is sent to the second input of the block 17. This command indicates whether or not forced balancing of the capacitors 33, 34 (Fig. 3) is needed in the DC link 29. At the same time, a signal from the output of the block is sent to the third input of the block 19 21. This signal indicates which base voltage vector was selected in the previous step of selecting vectors in the second vector plane of FIG. 4, b.

Block 19 works like block 18, i.e. selects the optimal base voltage vector for efficient control of the active voltage rectifier 26 of the second frequency converter 25 (Fig. 2). The selected voltage vector provides: the minimum number of switchings of the keys in the active voltage rectifier 26 of the second frequency converter 25, increases the speed of the active voltage rectifier 26, supports voltage balancing on two capacitors of the DC link of the active voltage rectifier 26.

At the second output of block 19, control signals are generated by the keys of the active rectifier 26 of the second frequency converter 25.

и состояния баланса напряжений на конденсаторах звена постоянного тока высоковольтного преобразователя частоты работает следующим образом.Block calculation 17 (Fig. 1) of the set value of the active current

and the state of the voltage balance on the capacitors of the DC link of the high-voltage frequency converter operates as follows.

осуществляется с помощью пропорционально-интегрального (ПИ) регулятора, находящегося внутри блока 17, на входы которого подаются ранее указанные напряжения.A signal is received at the first input of the indicated block, indicating what voltage value should be on two series-connected capacitors 33 and 34 in the DC link 29 (Fig. 3). The second input of block 17 receives a signal indicating the current voltage value on both capacitors and on each of them separately. Formation of the set value of the active current

is carried out using the proportional-integral (PI) controller located inside the block 17, to the inputs of which the previously indicated voltages are supplied.

At the same time, a signal is generated at the second output of block 17 (Fig. 1), indicating the need for natural or forced balancing of the voltages on the capacitors 33 and 34 of the DC link 29 (Fig. 3). It was previously described how voltage balancing is carried out on these capacitors.

The control device for a high-voltage frequency converter for short-term asymmetrical voltage dips (Fig. 1) works as follows.

источника питания 2. Если эта величина не превышает 5 %, то управление высоковольтным преобразователем частоты 6 осуществляет система управления 4 как в прототипе. При этом используется метод ШИМ с удалением восьми выделенных гармоник напряжения и девятью переключениями ключей активного выпрямителя за четверть периода. Block calculation 3 determines the value of the coefficient of asymmetry stress

power source 2. If this value does not exceed 5%, then the high-voltage frequency converter 6 is controlled by a control system 4 as in the prototype. In this case, the PWM method is used with the removal of eight selected voltage harmonics and nine switching of the active rectifier keys in a quarter of a period.

источника питания 2 более 5 %, то блок вычисления 3 передает управление высоковольтным преобразователем частоты 6 системе управления 11, которая осуществляет релейно-векторное управление ключами двух активных выпрямителей 26 (фиг. 2). Ранее была подробно, описана работа каждого блока системы управления 11.If the magnitude of the voltage unbalance

of the power supply 2 is more than 5%, the calculation unit 3 transfers control of the high-voltage frequency converter 6 to the control system 11, which performs relay-vector control of the keys of two active rectifiers 26 (Fig. 2). Previously, the operation of each block of the control system 11 was described in detail.

In FIG. 9, FIG. 10 are oscillograms explaining the operation of the inventive control device of a three-phase three-level active voltage rectifier 26 of a high-voltage frequency converter 6.

и текущее

значения активной составляющей тока источника питания 2; г – заданное

и текущее

значения реактивной составляющей тока источника питания 2; д – команда

для активных выпрямителей 26 на увеличение или уменьшение текущего активного тока

источника питания 2 в 1-ом или 2-ом диапазонах регулирования; е – команда

для активных выпрямителей 26 на увеличение или уменьшение текущего реактивного тока

источника питания 2 в 1-ом или 2-ом диапазонах регулирования; ж – выбранный базовый вектор напряжения для эффективного управления активным выпрямителем напряжения 26 первого преобразователя частоты 24, который сформирован на первом выходе блока 18; и – выбранный базовый вектор напряжения для эффективного управления активным выпрямителем напряжения 26 второго преобразователя частоты 25, который сформирован на первом выходе блока 19.The oscillograms were obtained as a result of modeling in the Matlab / Simulink software environment and give a visual representation of the operation of the relay-vector control of these rectifiers with short-term asymmetrical voltage dips. A frequency-controlled synchronous electric drive of the stand of a continuous rolling mill is adopted as a control object. Here: a - instantaneous values of the phase voltage of the power source 2; b - instantaneous phase currents of the power source 2; in - given

and current

the values of the active component of the current of the power source 2; g - given

and current

the value of the reactive component of the current of the power source 2; d - team

for active rectifiers 26 to increase or decrease the current active current

power supply 2 in the 1st or 2nd regulation ranges; e - team

for active rectifiers 26 to increase or decrease the current reactive current

power supply 2 in the 1st or 2nd regulation ranges; g is the selected base voltage vector for efficiently controlling the active voltage rectifier 26 of the first frequency converter 24, which is formed at the first output of block 18; and - the selected base voltage vector for efficiently controlling the active voltage rectifier 26 of the second frequency converter 25, which is formed at the first output of block 19.

On the oscillograms (Fig. 9, Fig. 10), which display five periods of mains voltage from 0 to 0.1 s, three time intervals can be distinguished.

, когда напряжение сети симметричное, а заданное значение активной составляющей тока источника питания 2 равно нулю (

). First time interval

when the mains voltage is symmetrical, and the set value of the active component of the current of the power source 2 is zero (

)

, когда напряжение сети симметричное, а заданное значение активной составляющей тока источника питания 2 равно

. Second time interval

when the voltage of the network is symmetrical, and the set value of the active component of the current of the power source 2 is

.

, когда напряжение сети несимметричное, а заданное значение активной составляющей тока источника питания 2 равно

.Third time interval

when the voltage is unbalanced, and the set value of the active component of the current of the power source 2 is

.

Note that in all three time intervals the control system for the high-voltage frequency converter 11 worked (Fig. 1), which in fact was supposed to turn on only in the third time interval, with short-term asymmetrical voltage dips.

в фазе А произошел провал напряжения на 40 %, при этом в фазах В и С напряжения номинальные

.In FIG. 9, and at time

in phase A, a voltage dip of 40% occurred, while in phases B and C the nominal voltage

.

значения фазных токов источника питания 2 равны нулю, так как

. При этом отклонение мгновенных фазных значений токов источника питания 2 достигает 85 А, что обусловлено работой релейных регуляторов активного 14 и реактивного 15 токов.In FIG. 9, b on the first time interval

the values of the phase currents of the power source 2 are equal to zero, since

. In this case, the deviation of the instantaneous phase values of the currents of the power source 2 reaches 85 A, which is due to the operation of the relay controllers of the active 14 and reactive 15 currents.

и на третьем временном интервале

действующие значения фазных токов источника питания 2 равны номинальным значениям 600 А, при

. Наличие отклонений тока (высокочастотных колебаний тока) на фоне основных гармоник фазных токов источника питания 2 достигает 85 А, что обусловлено работой релейных регуляторов активного 14 и реактивного 15 токов. При этом коэффициент несинусоидальности токов на втором и третьем временных интервалах не превышает соответственно 5 % и 10 %, что является допустимым значением. In FIG. 9, b on the second time interval

and in the third time interval

the effective values of the phase currents of the power source 2 are equal to the nominal values of 600 A, at

. The presence of current deviations (high-frequency current fluctuations) against the background of the main harmonics of the phase currents of the power supply 2 reaches 85 A, which is due to the operation of the relay controllers of the active 14 and reactive 15 currents. Moreover, the coefficient of non-sinusoidality of the currents in the second and third time intervals does not exceed 5% and 10%, respectively, which is an acceptable value.

ток задания

изменился скачком от 0 А до 1250 А, при этом время переходного процесса изменения мгновенных значений фазных токов источника питания 2 составляет

(фиг. 9,б). Такое высокое быстродействие заявляемой системы управления высоковольтным преобразователем частоты свидетельствует о его достоинстве.Note that at time

reference current

changed abruptly from 0 A to 1250 A, while the transition process of changing the instantaneous values of the phase currents of the power source 2 is

(Fig. 9, b). Such a high speed of the inventive control system of a high voltage frequency converter indicates its dignity.

произошел провал напряжения в фазе А на 40 %, при этом осциллограммы фазных токов источника питания 2 (фиг. 9,б) на третьем и втором временных интервалах практически одинаковы. Заявляемая система управления высоковольтным преобразователем частоты отработала указанный провал напряжения практически мгновенно, о чем свидетельствуют осциллограммы токов, на которых отсутствуют заметные провалы или всплески токов после момента времени

. Указанное поведение токов подтверждает высокую надежность и высокое быстродействие заявляемой системы управления высоковольтным преобразователем частоты.It was previously indicated that at time

there was a voltage failure in phase A by 40%, while the waveforms of the phase currents of power source 2 (Fig. 9, b) in the third and second time intervals are almost the same. The inventive control system of a high-voltage frequency converter worked out the indicated voltage dip almost instantly, as evidenced by the oscillograms of currents, on which there are no noticeable dips or surges of currents after a moment of time

. The specified behavior of the currents confirms the high reliability and high speed of the inventive control system of a high-voltage frequency converter.

и текущего

значения активной составляющей тока и источника питания 2. Ранее было указано, что указанные токи подаются на второй и первый входы релейного регулятора активного тока 14 (фиг. 1). На первом временном интервале

ток

, а мгновенное значение текущего тока изменяется в диапазоне

, так как работает система управления 11. На втором и третьем временных интервалах

ток

, а мгновенное значение текущего тока изменяется в диапазоне 1165

. При этом на первом и втором временных интервалах, когда напряжение сети симметричное, динамика изменения активного тока

относительно тока

имеет практически линейный характер (фиг. 9,в) в рамках ширины зоны гистерезиса релейного регулятора 14, а период высокочастотных колебаний тока

относительно тока

остается практически постоянным. In FIG. 9, the waveform of a given

and current

the values of the active component of the current and the power source 2. It was previously indicated that these currents are supplied to the second and first inputs of the relay controller of the active current 14 (Fig. 1). In the first time interval

current

, and the instantaneous value of the current current varies in the range

, since the control system 11. Works. On the second and third time intervals

current

, and the instantaneous value of the current current changes in the range of 1165

. Moreover, in the first and second time intervals, when the mains voltage is symmetrical, the dynamics of the active current

relative to current

has an almost linear character (Fig. 9, c) within the width of the hysteresis zone of the relay controller 14, and the period of high-frequency current oscillations

relative to current

remains almost constant.

относительно тока

имеет интервалы времени с линейным характером, а также интервалы времени с нелинейным характером. Интервалы времени с линейным характером имеют место, когда напряжение сети

(см. точки овала на фиг. 5) находится за пределами зоны перехода из первого диапазона регулирования во второй диапазон регулирования и наоборот. Ранее об особенностях указанного интервала времени упоминалось, что при этом влияние слагаемого

в уравнение (1) не проявлялось. Период колебаний высокочастотной составляющей тока

относительно тока

для указанного интервала времени (фиг. 9,в) остается практически постоянным.In the third time interval, when the mains voltage is asymmetrical, the active current changes

relative to current

has time intervals with a linear character, as well as time intervals with a non-linear character. Linear time intervals occur when mains voltage

(see the oval points in Fig. 5) is located outside the transition zone from the first regulation range to the second regulation range and vice versa. Earlier, it was mentioned that the influence of the term

in equation (1) did not appear. The oscillation period of the high-frequency component of the current

relative to current

for the indicated time interval (Fig. 9, c) remains almost constant.

(см. точки овала на фиг. 5) находится в зоне перехода из первого диапазона регулирования во второй диапазон регулирования и наоборот. Ранее об особенностях указанного интервала времени тоже отмечалось, при этом ощутимое влияние в уравнении (1) оказывает слагаемое

. Период колебаний высокочастотной составляющей тока

относительно тока

для указанного интервала времени (фиг. 9,в) не остается постоянным.Non-linear time intervals occur when the mains voltage

(see the oval points in Fig. 5) is in the transition zone from the first regulation range to the second regulation range and vice versa. Earlier, the features of the indicated time interval were also noted, while the term in the equation (1) has a noticeable effect

. The oscillation period of the high-frequency component of the current

relative to current

for the specified time interval (Fig. 9, c) does not remain constant.

источника питания 2. Напомним, заданное значение реактивной составляющей тока источника питания 2 должно быть равно нулю

. Ранее было указано, что указанные токи подаются на первый и второй входы релейного регулятора реактивного тока 15 (фиг. 1). На первом и втором временных интервалах

мгновенное значение текущего тока

изменяется в диапазоне

, так как работает система управления 11 (фиг. 1). При этом на первом и втором временных интервалах, когда напряжение сети симметричное, динамика изменения реактивного тока

относительно тока

имеет практически линейный характер (фиг. 9,г), а период колебаний тока

остается практически постоянным.In FIG. 9, d shows the waveform of the current value of the reactive component of the current

power source 2. Recall, the set value of the reactive component of the current of the power source 2 should be equal to zero

. It was previously indicated that these currents are supplied to the first and second inputs of the relay controller of reactive current 15 (Fig. 1). In the first and second time intervals

instantaneous value of current

varies in the range

, since the control system 11 (Fig. 1). Moreover, in the first and second time intervals, when the network voltage is symmetrical, the dynamics of the reactive current

relative to current

has an almost linear nature (Fig. 9, d), and the period of current oscillations

remains almost constant.

мгновенное значение тока

, также должно изменяться в диапазоне:

(фиг. 9,г). Однако, вследствие существенного влияния слагаемого

в уравнение (2), текущее значение реактивной составляющей тока

источника питания 2 в отдельные моменты времени выход за граничные значения, достигая -200 А и +140 А, т.е. превышает в 2,4 и 1,6 раз граничные значения. Ранее о влиянии слагаемого

уже упоминалось. Указанные нарушения граничных значений токов в релейном регуляторе реактивного тока 15 происходят соответственно при переходе из второго диапазона регулирования в первый диапазон регулирования и наоборот. В процессе работы заявляемого устройства длительность во времени указанных нарушений граничных значений токов

составляет около 20 %. Учитывая, что доля составляющей тока

в сетевом токе

источника питания 2 незначительная, не более 16 %, то в мгновенных значениях фазных токов указанные нарушения существенно не проявляются. Полученный вывод подтверждается осциллограммами токов на фиг. 9,б, где явно отсутствуют существенные провалы или всплески токов. Однако коэффициент несинусоидальности токов на третьем временном интервале увеличивается до 10 %, что является допустимым значением, при этом на втором временном интервале указанный коэффициент составлял 5 %.In the third time interval

instantaneous current value

should also vary in the range:

(Fig. 9, g). However, due to the significant influence of the term

in equation (2), the current value of the reactive component of the current

power supply 2 at certain points in time, exceeding the boundary values, reaching -200 A and +140 A, i.e. exceeds 2.4 and 1.6 times the boundary values. Earlier on the influence of the term

already mentioned. These violations of the boundary values of the currents in the relay controller of the reactive current 15 occur respectively during the transition from the second regulation range to the first regulation range and vice versa. In the process of operation of the inventive device, the time duration of these violations of the boundary values of currents

is about 20%. Given that the fraction of the current component

in mains current

power supply 2 is insignificant, not more than 16%, then in the instantaneous values of phase currents these violations are not significantly manifested. The resulting conclusion is confirmed by the waveforms of the currents in FIG. 9b, where there are clearly no significant dips or surges of currents. However, the coefficient of non-sinusoidality of the currents in the third time interval increases to 10%, which is an acceptable value, while in the second time interval the specified coefficient was 5%.

- «выбрать вектор из группы длинных векторов»;

- «выбрать вектор из группы средних векторов»;

- «выбрать вектор из группы коротких векторов». Ранее было указано, что эти команды подаются на первый вход блока 16 (фиг. 1).In FIG. 10, e shows the waveform, which displays the command generated at the output of the three-position relay controller 14:

- “select a vector from a group of long vectors”;

- “select a vector from the group of average vectors”;

- "select a vector from the group of short vectors." It was previously indicated that these commands are sent to the first input of block 16 (Fig. 1).

, когда напряжение сети симметричное, выбираются длинные и средние вектора, т.е. регулирование мгновенных входных напряжений активных выпрямителей 26 первого 24 и второго 25 преобразователей частоты (в пределах от 0,75 до 1,0 их номинальных значений) осуществляется во 2-ом диапазоне регулирования. In the first and second time intervals

when the network voltage is symmetrical, long and medium vectors are selected, i.e. regulation of the instantaneous input voltages of the active rectifiers 26 of the first 24 and second 25 frequency converters (ranging from 0.75 to 1.0 of their nominal values) is carried out in the 2nd regulation range.

, когда выбирается короткий вектор, чтобы отработать скачкообразное изменение заданного значения активного тока от 0 А до 1250 А. При этом фазные токи источника питания 2 за время переходного процесса

(фиг. 9,б) достигают установившихся значений.The exception is the time interval

when a short vector is selected in order to work out an abrupt change in the set value of the active current from 0 A to 1250 A. In this case, the phase currents of the power source 2 during the transient

(Fig. 9, b) reach steady-state values.

, когда напряжение сети несимметричное, на осциллограмме (фиг. 10,д) имеют место временные интервалы, когда группа из длинных и средних векторов (2-ой диапазон регулирования) меняется на группу из средних и коротких векторов (1-ый диапазон регулирования) и наоборот. Ранее об этом было подробно описано, когда пояснялась работа трехпозиционного релейного регулятора активного тока 14 (фиг. 8). In the third time interval

when the voltage of the network is unbalanced, there are time intervals on the waveform (Fig. 10, e) when a group of long and medium vectors (2nd regulation range) changes to a group of medium and short vectors (1st regulation range) and vice versa. This was previously described in detail when the operation of the three-position relay controller of the active current 14 (Fig. 8) was explained.

The waveform analysis of FIG. 10, d shows that when the voltage drop in phase A by 40% in the inventive device, 8 long, 8 medium vectors and 5 short, 5 medium vectors for the half-period of the mains voltage were selected to provide a given value of the active component of the current of the power source 2. When In this case, the retention times of the selected vectors are not the same, especially when approaching the boundary of the change of control ranges, as previously mentioned.

- «увеличить текущее значение реактивного тока

источника питания 2», (фиг. 8,в)

- «уменьшить текущее значение реактивного тока

источника питания 2». Ранее было указано, что эти команды подаются на второй вход блока 16 (фиг. 1).In FIG. 10, f shows an oscillogram that displays which command is generated at the output of the on-off relay controller 15 (Fig. 1):

- “increase the current value of the reactive current

power supply 2 ", (Fig. 8, c)

- “reduce the current value of the reactive current

power supply 2 ". It was previously indicated that these commands are sent to the second input of block 16 (Fig. 1).

, когда напряжение сети симметричное, продолжительности удержания выбранной команды

или

существенно не меняются. Однако анализ осциллограммы на фиг. 10,е показывает, что при ранее указанном провале напряжения (40 %) продолжительность удержания выбранной команды

или

существенно зависит от углового положения вектора напряжения сети

на третьей плоскости (см. овал на фиг. 5). In the first and second time intervals

when the mains voltage is symmetrical, the holding time of the selected command

or

do not change significantly. However, the analysis of the waveform in FIG. 10e shows that, at the previously indicated voltage drop (40%), the duration of holding the selected command

or

significantly depends on the angular position of the network voltage vector

on the third plane (see oval in Fig. 5).

- «уменьшить текущее значение реактивного тока

источника питания 2» (фиг. 10,е). Ранее упоминалось, что команда

выбрана, чтобы удержать текущее значение реактивного тока

источника питания 2 в заданных границах регулирования, вследствие заметного влияния слагаемого

в уравнении (2). In the zone of change of the 1st regulation range to the 2nd regulation range, the command duration prevails

- “reduce the current value of the reactive current

power source 2 "(Fig. 10, e). Previously mentioned that the team

selected to hold current reactive current value

power supply 2 within the specified regulation limits, due to the noticeable influence of the term

in equation (2).

- «увеличить текущее значение реактивного тока

источника питания 2». Ранее упоминалось, что команда

выбрана, чтобы удержать текущее значение реактивного тока

источника питания 2 в заданных границах регулирования, вследствие заметного влияния слагаемого

в уравнении (2).In the zone of change of the 2nd regulation range to the 1st regulation range, the command duration substantially prevails

- “increase the current value of the reactive current

power supply 2 ". Previously mentioned that the team

selected to hold current reactive current value

power supply 2 within the specified regulation limits, due to the noticeable influence of the term

in equation (2).

In FIG. 10g shows a waveform that indicates the selected base voltage vector for efficiently controlling the active voltage rectifier 26 in the first frequency converter 24, which is formed at the first output of block 18.

It was previously indicated that at the second output of block 18 (Fig. 1), the selected base voltage vectors generate the control signals with the keys of the active rectifier 26 of the first frequency converter 24.

In FIG. 10, and a waveform is shown that indicates the selected base voltage vector for efficiently controlling the active voltage rectifier 26 in the second frequency converter 25, which is formed at the first output of block 19.

It was previously indicated that at the second output of block 19 (Fig. 1), the selected base voltage vectors generate the control signals with the keys of the active rectifier 26 of the second frequency converter 25.

Thus, the generated control signals at the second outputs of blocks 18 and 19 are the output signals of the control system 11 by a high-voltage frequency converter with an asymmetric voltage of the power source. These signals are fed to the first and second control inputs of the high-voltage frequency converter 6.

Based on the foregoing, it follows that in the inventive device, the relay-vector key management of three-phase three-level active voltage rectifiers of a high-voltage frequency converter ensures high speed of the electric drive and its resistance to disturbances from the supply network, especially for short-term asymmetrical voltage dips. Moreover, the deviations of the instantaneous values of the currents of the power source and the voltages on the capacitors of the DC link do not exceed the permissible values.

Of great importance in the inventive device is the proposed structure of the switch table of the switches of active voltage rectifiers, which is developed based on the conditions of the minimum number of switchings of the keys in these rectifiers; improving the performance of the claimed control system; maintaining a voltage balance on two capacitors of the DC link of active voltage rectifiers. By minimizing the number of key switching in active voltage rectifiers and increasing their speed, the efficiency of the high-voltage frequency converter increases.

In addition, the inventive device provides a high power factor, almost equal to unity, a satisfactory harmonic composition of the input currents, even with short-term asymmetrical voltage drops.

Claims (1)

A control device for a high-voltage frequency converter containing a voltage sensor of the power source, the input of which is connected to the output of the three-phase power source, and the output to the voltage asymmetry calculation unit of the power source, the first output of which is connected to the first input of the frequency converter control system at a symmetrical voltage of the power source, and the second output is with a voltage regulator of the DC link, the output of which is connected to the second input of the specified control system of the converter m frequency, the first and second outputs of the specified control system are connected respectively to the first and second control inputs of the high-voltage frequency converter, the power input of which is connected to the power source, and the power output to the synchronous machine, to the first information output of the high-voltage frequency converter through the current sensor of the power source the third input of the control system of the frequency converter is connected, the fourth input of the specified control system is connected to the output of the voltage source sensor I, and the fifth input to the output of the DC link voltage sensor, three inputs of which are connected to the second, third and fourth information outputs of the high-voltage frequency converter, the sixth input of the frequency converter control system with a symmetrical voltage of the power source is connected to the reactive current regulator, according to the invention it equipped with a control system for a high-voltage frequency converter with asymmetric voltage of the power source, including an active and reactive leaving currents of the power source, the first input of which is connected to the output of the current sensor of the power source, and the second input to the first output of the phase-locked loop and the formation of the sector number on the third plane of the base vectors, the input of this unit is connected to the output of the voltage sensor of the power source, the first and the second outputs of the unit for calculating the active and reactive components of the currents are connected respectively to the first inputs of the relay controller of the active current and the relay controller of the reactive current, the outputs of the cat connected to the first and second inputs of the preliminary selection of the base voltage vector of the active rectifiers of the high-voltage frequency converter, the third input of the preliminary selection of the base voltage vector is connected to the second output of the phase-locked loop and the formation of the sector number on the third plane of the base vectors, while the second input active current relay controller is connected to the first output of the unit for calculating the set value of the active current and balance state voltage at the capacitors of the DC link of the high-voltage frequency converter, the first input of the specified calculation unit is connected to the output of the voltage regulator of the DC link, while the second input of the relay reactive current regulator is connected to the output of the reactive current regulator, the first output of the preliminary selection of the base voltage vector of the active rectifiers of the high voltage the frequency converter is connected to the first input of the base voltage vector selection block for the active rectifier of the first frequency converter and the formation of control signals with the keys of the specified rectifier, the second output of the preliminary selection of the base voltage vector of the active rectifiers of the high-voltage frequency converter is connected to the first input of the base voltage vector selection block for the active voltage rectifier of the second frequency converter and the formation of control signals with the keys of the rectifier, the second the inputs of the indicated blocks of the selection of the base voltage vector are connected to the second one of the unit for calculating the set value of the active current and the state of the voltage balance on the capacitors of the DC link of the high-voltage frequency converter, the second input of this calculation unit is connected to the output of the voltage sensor of the DC link, the first output of the base voltage vector selection unit for the active voltage rectifier of the first frequency converter and generating the control signals with the keys of the rectifier through the storage unit of its previous value of the base voltage vector The unit is connected to its third input, while the second output of the base voltage vector selection block for the active voltage rectifier of the first frequency converter and the formation of control signals by the keys of the specified rectifier is connected to the first control input of the high voltage frequency converter, the first output of the base voltage vector selection block for the active voltage rectifier the second frequency converter and the formation of control signals with the keys of the specified rectifier through its storage unit previous value of the base voltage vector is connected to its third input, the second output reference voltage vector selection unit for the second active rectifier voltage frequency converter and generating control signals of said switches of the rectifier is connected to a second control input of the high-frequency inverter.

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