RU166814U1 - HIGH VOLTAGE FREQUENCY CONVERTER - Google Patents

Abstract

1. A high-voltage frequency converter containing a three-phase multi-winding transformer and a multi-level voltage inverter located in cabinets with an air cooling system, the multi-level inverter contains a control module, power units connected in series with three-phase semi-controlled rectifiers, single-phase voltage inverters and generates a three-phase voltage with an effective value of up to 10 kV with high harmonic quality on the stator windings of synchronous and asynchronous nomi motors 10 kV voltage regulating voltage according to the vector control law, characterized in that the three-phase multi-winding transformer is made at 6 / 0.71 kV or 10 / 0.71 kV and generates a three-phase voltage of variable frequency in the range from 0 to 120 Hz. 2 . The high-voltage frequency converter according to claim 1, characterized in that the number of 15 or 27 power units with rectifiers and single-phase voltage inverters is selected depending on the voltage of 6 or 10 kV with a common pulse rectification of the converter 30 or 54, respectively. 3. The high-voltage frequency converter according to claim 1, characterized in that the three-phase multi-winding transformer comprises an assembled core with three primary windings connected in parallel, and its secondary windings are made at an output voltage of 0.71 kV with spatial phase shifts of 12 electrical degrees or 6.67 relative to each other electrical degrees depending on the voltage of 6 or 10 kV, respectively. 4. The high-voltage frequency converter according to claim 1, characterized in that the control module is made with an algorithm for working with

Description

HIGH VOLTAGE FREQUENCY CONVERTER

FIELD OF TECHNOLOGY.

The utility model relates to the field of electrical engineering, in particular, to automated electric drives and converting equipment, and is intended to convert an input AC voltage of 6 kV and 10 kV of industrial frequency 50 Hz to alternating voltage with a frequency of 0 to 120 Hz and a value of 0 to 6 kV and from 0 to 10 kV, necessary for regulating the speed of asynchronous and synchronous electric motors (ED) of alternating current according to the vector and scalar control laws.

BACKGROUND OF THE INVENTION

The prior art high-voltage frequency converter (VFD) (RU 144730 U1, publication date 07/29/2014, patent holders of AK Transneft, Baltnefteprovod LLC, NII TNN LLC), adopted as the closest analogue, containing an actuator, electric motor, transformer and high voltage frequency converter. A high-voltage frequency converter with a voltage of 10 kV and a power of 2500 kW includes a multi-winding transformer and a multi-level voltage inverter, and the high-voltage frequency converter is installed in a block container and contains four cabinets: a multi-winding transformer cabinet, two multi-level voltage inverter cabinets and a braking resistor cabinet.

The disadvantage of the closest analogue is the inability to work with AC electric motors with a voltage of 6 kV and with a frequency of regulation of the output voltage up to 120 Hz, the lack of a uniform distribution of the phases of the consumed current from the network. The disadvantages are due to the lack of a three-phase multi-winding transformer containing an assembled core with three primary windings connected in parallel and with secondary windings made at an output voltage of 0.71 kV with spatial phase shifts of 12 electrical degrees relative to each other, and the absence of a control module with a scalar pulse-width pulse generator modulated signal to 15 and 27 power blocks with voltage inverters.

TECHNICAL RESULT.

The technical result consists in expanding the technical characteristics of the high-voltage frequency converter for voltage of 6 kV and 10 kV and for the adjustable output frequency range from 0 to 120 Hz, necessary to control the speed of asynchronous and synchronous motors to a rated voltage of 6 kV and 10 kV with the possibility of regulating how according to vector and scalar control laws with a uniform distribution of the phases of the current consumed from the network. The technical result of the claimed utility model is achieved by the fact that in a high-voltage frequency converter containing a three-phase multi-winding transformer and a multi-level voltage inverter located in cabinets with an air cooling system, the multi-level inverter contains a control module, power units connected in series with three-phase semi-controlled rectifiers, single-phase voltage inverters and generates a three-phase voltage with an effective value of up to 10 kV with high harmonic quality on the stator windings of synchronous and asynchronous motors with a rated voltage of 10 kV for speed control according to the vector control law, a three-phase multi-winding transformer is made for voltage 6 / 0.71 kV or 10 / 0.71 kV, and generates a three-phase voltage of variable frequency in the range from 0 up to 120 Hz with an effective value from 0 to 6 kV or from 0 to 10 kV. The number of power units with rectifiers and single-phase voltage inverters 15 or 27 is selected depending on the voltage of 6 or 10 kV with a total pulse frequency rectification of the converter 30 or 54, respectively. A three-phase multi-winding transformer contains an assembled core with three parallel connected primary windings, and its secondary windings are made at an output voltage of 0.71 kV with spatial phase shifts of 12 electrical degrees or 6.67 electrical degrees relative to each other depending on a voltage of 6 or 10 kV, respectively. The control module is made with an algorithm for working with scalar and vector control laws, provides uniform distribution in phases of the current s consumed from the network, and can control the operation of up to 27 power units with voltage inverters.

ESSENCE OF A USEFUL MODEL

Due to the fact that a three-phase multi-winding transformer in a high-voltage frequency converter is made at 6 / 0.71 kV or 10 / 0.71 kV, and the multi-level inverter control module generates a three-phase voltage of variable frequency in the range from 0 to 120 Hz and with an effective value from 0 to 6 kV or from 0 to 10 kV to the stator windings of synchronous and asynchronous electric motors with a rated voltage of 6 kV or 10 kV, a technical result is achieved — the technical characteristics of the high-voltage frequency converter are expanded by voltage of 6 kV and 10 kV and a range of adjustable output frequencies from 0 to 120 Hz, necessary to control the speed of asynchronous and synchronous motors to a rated voltage of 6 kV and 10 kV.

The number of power units with rectifiers and single-phase voltage inverters 15 or 27 is selected depending on the voltage of 6 or 10 kV with a total pulse frequency rectification of the converter 30 or 54, respectively. A three-phase multi-winding transformer contains an assembled core with three parallel connected primary windings, and its secondary windings are made at an output voltage of 0.71 kV with spatial phase shifts of 12 electrical degrees or 6.67 electrical degrees relative to each other depending on a voltage of 6 or 10 kV, respectively. The control module is made with an algorithm for working with scalar and vector control laws, provides uniform distribution in phases of the current consumed from the network, and can control the operation of 15 and 27 power units with voltage inverters. In the claimed utility model are provided:

- the ability to use the required number of serially connected single-phase voltage inverters with the formation of a three-phase voltage of variable frequency in the range from 0 to 120 Hz and an effective value from 0 to 6 kV and from 0 to 10 kV supplied to the stator windings of synchronous and asynchronous electric motors of 6 and 10 kV ;

- implementation of scalar and vector control laws in a high-voltage frequency converter;

- uniform distribution in phases of the current consumed from the network due to the implemented control algorithm.

DRIVEN FIGURES.

In FIG. 1a is a functional diagram of a high voltage frequency converter for a voltage of 6 kV; in FIG. 16 is a functional diagram of a high voltage frequency converter for a voltage of 10 kV; in FIG. 2 - distribution into sections of the primary and secondary windings of the transformer at 6 kV; in FIG. 3 - distribution of sections of the primary and secondary windings of the transformer at 10 kV; in FIG. 4 - power cell of a multilevel voltage inverter; in FIG. 5 - waveforms of the output voltage and the distortion coefficient of the sinusoidality of the voltage curve of the high-voltage frequency converter; in FIG. 6 - waveforms of the input current and the distortion coefficient of the sinusoidality of the input current curve of the high-voltage frequency converter; in FIG. 7 is a vector diagram of an induction motor with vector control from a high voltage frequency converter; in FIG. 8 is a structural diagram of a high-voltage vector-controlled frequency converter; in FIG. 9 is a functional block diagram of a multiprocessor control unit; in FIG. 10 is a functional block diagram of a shaper of a multi-level vector pulse-width modulated signal (LHWM).

The following symbols are used in the figures given:

PR - fuses;

B - rectifier block;

F - filtering capacitor;

U3 - node discharge energy;

And - a voltage inverter for IGBT transistors.

DISCLOSURE OF A USEFUL MODEL.

The high-voltage frequency converter contains a three-phase multi-winding transformer pos. 4 (Fig. 1, a, 1, b) and a multi-level voltage inverter pos. 5 (Fig. 1, a, 1, b). Three-phase multi-winding transformer pos. 4 (Fig. 1, a, 1, b) is designed for voltage 6 / 0.71 kV or 10 / 0.71 kV, and the multi-level inverter 5 (Fig. 1, a, 1, b) contains series-connected power blocks pos . 3 (Fig. 1, a, 1, b) with three-phase semi-controlled rectifiers B (Fig. 4), single-phase voltage inverters And (Fig. 4) and generates a three-phase voltage of variable frequency in the range from 0 to 120 Hz and with an effective value from 0 to 6 kV or from 0 to 10 kV to the stator windings of synchronous and asynchronous electric motors, pos. 6 (Fig. 1, a, 1, b) with a rated voltage of 6 kV or 10 kV. The number of power blocks pos. 3 (Fig. 1, a, 1, b) with rectifiers B (Fig. 4) and single-phase voltage inverters AND (Fig. 4), select 15 (Fig. 1, a) or 27 (Fig. 1, b) depending from a voltage of 6 or 10 kV with a total pulse rate of rectification of the converter 30 or 54, respectively.

A three-phase multi-winding transformer (Fig. 2, 3) contains an assembled core with three parallel connected primary windings WcAl, WcA2, WcA3 and WcB1, WcB2, WcB3 and WcC1, WcC2, WcC3, (Fig. 2, 3) (in the prototype one primary winding ), and its secondary windings are made for an output voltage of 0.71 kV and 15 (poses a1a, a1b, a1c, ... a5a, a5b, a5c, b1a, b1b, b1c, b5a, b5b, b5c, c1a, c1b, c1c, c5a, c5b, c5c, Fig. 2) or 27 (pos. a1a, a1b, a1c, ... a9a, a9b, a9c, b1a, b1b, b1c, b9a, b9b, b9c, c1a, c1b, c1c, c9a, c9b, c9c, Fig. 3) separate secondary windings made with spatial phase shifts of 12 (pos. -24 °, -12 °, 0 °, 132 °, 144 ° ph 2) and 6.67 (items 1, 2, 3, 4, 5, 6, 7, 8, 9 of Fig. 3) electrical degrees depending on the voltage of 6 or 10 kV, respectively. Control module pos. 2 (Fig. 1, a, 1, b) is made with an algorithm for working with scalar and vector control laws, provides uniform phase distribution of the current consumed from the network, and can control the operation of 15 and 27 power blocks with voltage inverters.

In contrast to the prototype, the inventive high-voltage frequency converter can be performed, for example, at the input and output voltages of 6 kV (Fig. 1, a) or 10 kV (Fig. 1, b) (in the prototype only 10 kV) with a rectification pulse rate of 30 or 54 multiple (in the prototype only 54 times the pulse rectification circuit) with a uniform distribution of current consumption and with the control module pos. 2 (Fig. 1, a, 1, b) capable of controlling the operation of 15 and 27 power units with voltage inverters.

A high-voltage frequency converter for an input voltage of 6 kV (Fig. 1, a) (there is no design in the prototype), 10 kV (Fig. 1, b) contains a three-phase multi-winding transformer pos. 4 (Fig. 1, a, 1, b), the outputs of the power blocks A1-A6 (Fig. 1, a) and A1-A9 (Fig. 1, b) are connected in series with the energy dumping units of ultrasound (Fig. 4) ( absent in the prototype) in phase U, B1-B6 (Fig. 1, a) and pos. B1-B9 (Fig. 1, b) in phase V, pos. C1-C6 (Fig. 1, a) and pos. C1-C9 (Fig. 1, b) in phase W, control module 2 (Fig. 1, a, 1, b) with vector sensorless and scalar control, interface module pos. 9 (Fig. 1, a, 1, b) with the control panel pos. 9 (Fig 1, a, 1, b) based on an industrial computer.

Three-phase multi-winding transformer is a transformer of dry insulation class for voltage 6 / 0.71 kV (Fig. 2), 10 / 0.71 kV (Fig. 3) (in the prototype 10 / 0.69 kV). Unlike the prototype, it has an assembled core with three parallel connected primary windings pos.WcA1, WcA2, WcA3 and WcB1, WcB2, WcB3 and WcC1, WcC2, WcC3, (Fig. 2, 3) (in the prototype one primary winding) 15 ( pos. a1a, a1b, a1c, ... a5a, a5b, a5c, b1a, b1b, b1c, b5a, b5b, b5c, c1a, c1b, c1c, c5a, c5b, c5c, Fig. 2) or 27 (pos. a1a, a1b, a1c, a9a, a9b, a9c, b1a, b1b, b1c, ... b9a, b9b, b9c, c1a, c1b, c1c, c9a, c9b, c9c, Fig. 3) separate secondary windings made with spatial phase shifts relative to each other each other at 12 electrical degrees (-24 °, -12 °, 0 °, 132 °, 144 ° Fig. 2) and 6.67 electrical degrees (pos. 1, 2, 3, 4, 5, 6, 7, 8 , 9 of Fig. 3) depending the voltage of 10 kV or 6, respectively (in the prototype 27 axially separate secondary windings). The transformer converts the mains voltage into a three-phase voltage system to power the power units.

Voltage inverter pos. 5 (Fig. 1, a, 1, b) consists of:

- series-connected power blocks pos. 3 (Fig. 1, a, 1, b) in the amount of 15 for 6 kV (pos. A1-A5, B1-B5, C1-C5 Fig. 1, a) and 27 for 10 kV (pos. A1-A9, B1-B9, C1-C9 in Fig. 1, b) of a series-connected single-phase voltage inverters And (Fig. 4) with an ultrasonic energy reset unit (Fig. 4) in each power unit;

- control module pos. 2 (Fig. 1, a, 1, b);

- interface module pos. 9 (Fig. 1, a, 1, b) with the control panel pos. 10 (Fig. 1, a).

Power blocks pos. 3 (Fig. 1, a, 1, b) of a high-voltage frequency converter are powered from the secondary windings of a three-phase multi-winding transformer pos. 4 (Fig. 1, a, 1, b) with a three-phase alternating voltage of 710 V (in the prototype 690 V) and consist of a thyristor rectifier B (Fig. 4), filtering polypropylene capacitors F (Fig. 4) (in the prototype film capacitors) , as well as a node for power dumping on IGBT transistors UZ (Fig. 4), a single-phase voltage inverter And (Fig. 4) (in the prototype there is no node for power dumping on IGBT transistors).

To obtain a three-phase alternating voltage in the range from 0 to 10 kV (in the prototype only 10 kV) or from 0 to 6 kV and a variable frequency from 0 to 120 Hz (there is no variable frequency in the prototype), series-connected power units pos. 3 (Fig. 1, a. 1, b). A low ripple coefficient of the input current is provided by a 30-pulse rectification circuit for 6 kV version, thanks to the use of 5 power units (A1-A5, B1-B5, C1-C5 Fig. 1, a) in each phase U, V, W (Fig. 1a) of a voltage inverter, or a 54-pulse rectification circuit for 10 kV design, due to the use of 9 power units (A1-A9, B1-B9, C1-C9 in Fig. 1, b) in each phase of the voltage inverter U, V , W (Fig. 1, a). The power blocks of the voltage inverter are controlled by the principle of vector pulse-width modulation - LHWM (in the prototype pulse-width modulated PWM) with a uniform distribution of the current load in power blocks (this function is not in the prototype). Overvoltages in the DC link are eliminated due to the discharge of additional energy into the resistors due to the use of the ultrasonic energy reset unit (Fig. 4) on IGBT transistors (this function is not in the prototype). Groups of power blocks are connected according to the "star" scheme, with floating neutral. Power block pos. 3 (Fig. 1, a. 1, b) of a multi-level voltage inverter is a complete functional unit with the implementation of protection against:

- short circuits;

- malfunctions of the transistor control driver;

- overheating of the IGBT module;

- malfunctions of the transistor power circuits (in the prototype there is no protection);

- increase the voltage in the DC link;

- lowering the voltage in the DC link;

- phase failure at the input of the cell of a multilevel voltage inverter;

- thyristor control synchronization errors (there is no protection in the prototype).

IMPLEMENTATION OF WORK.

Interaction between the control module pos. 2 (Fig. 1, a, 1, b) and power blocks pos. 3 (Fig. 1, a, 1, b) occurs through the communication interface unit pos. 1 (Fig. 9) of the control module. The control signals include a switching function, the resolution of the thyristors and IGBT modules, as well as the reset of internal protections and the resolution of the energy reset of the DC link of the power unit to the braking resistors. Power blocks pos. 3 (Fig. 1, a, 1, b) receive an alternating three-phase supply voltage of 710 V from the isolated secondary windings of a multi-winding transformer pos. 4 (Fig. 1, a, 1, b). Thus, all the power blocks A1-A6 (Fig. 1, a) and A1-A9 (Fig. 1, b), B1-B6 (Fig. 1, a) and B1-B9 (Fig. 1, b), C1-C6 (Fig. 1, a) and C1-C9 (Fig. 1, b) of the high-voltage frequency converter are isolated from each other and can operate independently. Using independent 15 secondary windings (pos. A1a, a1b, a1c, a5a, a5b, a5c, b1a, b1b, b1c, b5a, b5b, b5c, c1a, c1b, c1c, c5a, c5b, c5c, Fig. 2) and 27 secondary windings (pos. a1a, a1b, a1c, a9a, a9b, a9c, b1a, b1b, b1c, b9a, b9b, b9c, c1a, c1b, c1c, c9a, c9b, c9c, Fig. 3) allows you to organize the phase shift between secondary windings, which is used to reduce harmonic distortion in the form of current drawn from the network.

To reduce the dynamic inrush current when charging capacitors Ф (Fig. 4) of all power blocks, a smooth charge of these capacitors is organized. The charge is produced by a smooth increase in the thyristor opening angle of one of the phases of the semi-controlled rectifier B (Fig. 4) of the power unit. At the end of the charge stage, the voltage level on the filter capacitor F is checked (Fig. 4). If the filter capacitor F (Fig. 4) is charged, then all thyristors of rectifier B are allowed to control (Fig. 4), otherwise, a charge error signal is generated and control is removed from the thyristor.

WORK OF THE OFFERED DEVICE.

The control module 2 (Fig. 1, a, 1, b) is organized as a multiprocessor control system for a high-voltage frequency converter with a voltage of 6 or 10 kV (Fig. 9) with intelligent microprocessor units and consists of:

- interface communication units pos. 1 (Fig. 9) with power units;

- interface communication units pos. 2 (Fig. 9) with input / output current sensors,

- a calculator unit based on a DSP processor, an ARM interface microprocessor, and a bus interface module based on a PLD matrix pos. 3 (Fig. 9), for organizing BLVDS bus pos. 5 (Fig. 9) and CAN channel pos. 4 (Fig. 9);

- interface module pos. 6 (Fig. 9) for organizing communication with the process control system and the operator panel;

- blocks of analog poses. 8 (Fig. 9) and discrete pos. 7 (Fig. 9) input / output. The control module provides parallel operation of the feedback information processing and control distribution, as well as the analysis and configuration of the control method based on distributed computing.

Processing feedback information in the control module pos. 2 (Fig. 1, a) is provided through the communication interface unit pos. 2 (Fig. 9) with independent sensors for input and output current, input and output voltage, temperature pos. 8 (Fig. 1, a).

Management of the power unit 3 (Fig. 1, a, 1, b) of the multilevel voltage inverter 6 kV and 10 kV is provided by the communication interface unit pos. 1 (Fig. 9) of the control module pos. 2 (Fig. 1, a, 1, b), includes the exchange of the switching function and the signals of commands and states. The commands provide control of thyristors B (Fig. 4), transistors And (Fig. 4), a reset node for ultrasound (Fig. 4) and the operating mode. The states include: driver control, voltage level control, input voltage control, IGBT temperature control, control module, integrity of the communication interface line.

The control module performs the functions of controlling the speed of rotation of the electric motor, as well as special control modes (such as switching to the mains, picking up the frequency of the electric motor running on the mains, and picking up the frequency converter of the coastal motor) and the functions of the emergency recorder, provides a set of input protection and exit:

- from short circuits and overload current;

- from overvoltage;

- increase and decrease in power voltage;

- from unacceptable decrease or disappearance of supply and operational voltage;

- control of phases of a power line;

- phase control at the output of the high-voltage frequency converter;

- from overheating of the converter modules and transformer;

- from breakdown of semiconductor power switches;

- from failure of the cooling system;

- from loss of excitation when working with a synchronous electric motor in the presence of an alarm system excitation;

- from communication failure in control circuits;

- from a malfunction in the power supply system of the control circuits;

- from locking the motor shaft;

- external fault (separate input) (for example, protection against deviation of the controlled pressure).

The high-voltage frequency converter uses vector and scalar control of asynchronous and synchronous motors. The use of vector control ensures the creation of a system with efficient use of the electric motor in terms of power and with minimal pulsations of the electromagnetic moment of the electric motor. The main components of vector control (Fig. 8) are the following blocks:

1. Observer N (Fig. 8) in sliding modes, which is used to determine the rotor flux linkage vector and the rotor speed of the electric motor rotor, adapt to changing the rotor time constant.

2. Current regulators RT (Fig. 8).

3. Magnetization flow regulator pos. PH (Fig. 8) of an induction motor.

4. The deviation regulator PO (Fig. 8) of the resulting rotor flux vector relative to the X axis of the rotating coordinate system.

5. The speed controller of the rotor of the electric motor PC (Fig. 8).

6. ZI intensity adjuster (Fig. 8) for forming the trajectory of the rotor speed of the electric motor.

(фиг. 7). Синхронная частота вращения определяется суммой электрической угловой скорости вращения ротора ω_s=ω+ω_r, полученной на выходе скользящего наблюдателя, и частоты скольжения ω_r. Частота скольжения получена из условия раздельного управления потока ротора и электромагнитного момента ω_r=i_syL_m/(T_rΨ_rm). Контур задания частоты скольжения является разомкнутым контуром при формировании угла поворота вектора потока ротора и зависит от постоянной времени ротора T_r. Адаптация к изменяющейся во времени постоянной времени ротора повышает чувствительность электропривода на изменяющуюся нагрузку. Контур управления электромагнитным моментом состоит из контуров регулирования составляющей потокосцепления ротора по оси Y

и контура тока i_sy.The vector control algorithm is based on the calculation of the angle of rotation ϑ _s of the rotor vector by integrating the synchronous speed ω _s . The parameters of the control system are calculated in the coordinate system (xy), which rotates with synchronous speed relative to the stationary coordinates (ab), and is oriented relative to the rotor flux vector

(Fig. 7). The synchronous rotation frequency is determined by the sum of the electric angular velocity of the rotor ω _s = ω + ω _r obtained at the output of the moving observer and the sliding frequency ω _r. The slip frequency is obtained from the condition of separate control of the rotor flux and the electromagnetic moment ω _r = i _sy L _m / (T _r Ψ _rm ). The slip frequency reference loop is an open loop when forming the angle of rotation of the rotor flow vector and depends on the rotor time constant T _r. Adaptation to the time-varying time constant of the rotor increases the sensitivity of the electric drive to the changing load. The control loop of the electromagnetic moment consists of control loops of the rotor flux linkage component along the Y axis

and current loop i _sy .

строится двухконтурным с внутренним контуром управления по току намагничивания

и с внешним по модулю потокосцепления ротора

(фиг. 8). Канал управления угловой скоростью ротора содержит два контура управления - внутренние по току статора

и контур потока ротора

и внешний по угловой скорости ротора ω. Контур по регулированию составляющей потока ротора

предназначен для компенсации динамической ошибки в функции углаRotor Flow Control Channel

built with a dual-circuit with an internal magnetization current control loop

and with the rotor flux linkage external

(Fig. 8). The rotor angular velocity control channel contains two control loops - internal stator current

and rotor flow path

and external in the angular velocity of the rotor ω. Rotor flow control circuit

designed to compensate for dynamic errors in the angle function

9 between the rotor flux linkage vector and the X axis of the rotating coordinate system with a synchronous rotation frequency (in the prototype there is no loop for dynamic error compensation in the angle).

The vector of the output voltage from 0 to 6 kV and from 0 to 10 kV of the high-voltage frequency converter in the output frequency range from 0 to 120 Hz is generated using the switching function obtained from the LUT signal. The principle of formation is shown in FIG. 10. At the first stage, the modulation reference signal is corrected in accordance with the voltage in the DC link. For this, the BC correction unit (Fig. 10) serves. The received signal is modulated using a reference sawtooth signal taking into account the number of power cells in the inverter phase. This occurs in the modulation unit BM (Fig. 8). In the distribution block BR (Fig. 8), the calculation of the switching function for the power unit. At this stage, the uniform current consumption in the power units of an individual phase is taken into account. As a result of this, an improvement in the harmonic quality of the current consumed from the network is achieved (Fig. 6), the static and dynamic losses in the power units are evenly distributed, and an output voltage with high harmonic quality is provided (Fig. 5).

Claims (4)

1. A high-voltage frequency converter containing a three-phase multi-winding transformer and a multi-level voltage inverter located in cabinets with an air cooling system, the multi-level inverter contains a control module, power units connected in series with three-phase semi-controlled rectifiers, single-phase voltage inverters and generates a three-phase voltage with an effective value of up to 10 kV with high harmonic quality on the stator windings of synchronous and asynchronous nomi motors cial voltage of 10 kV for controlling the vector control law speed, characterized in that the three-phase transformer formed on multiwinding voltage 6/10 or 0.71 kV / 0.71 kV and generates three-phase voltage of variable frequency in the range from 0 to 120 Hz. 2. The high-voltage frequency converter according to claim 1, characterized in that the number of 15 or 27 power units with rectifiers and single-phase voltage inverters is selected depending on the voltage of 6 or 10 kV with a common pulse rectification of the converter 30 or 54, respectively. 3. The high-voltage frequency converter according to claim 1, characterized in that the three-phase multi-winding transformer contains an assembled core with three primary windings connected in parallel, and its secondary windings are made at an output voltage of 0.71 kV with spatial phase shifts of 12 electrical degrees or 6 relative to each other , 67 electrical degrees depending on the voltage of 6 or 10 kV, respectively. 4. The high-voltage frequency converter according to claim 1, characterized in that the control module is made with an algorithm for working with scalar and vector control laws, provides uniform distribution in phases of the current consumed from the network, and can control up to 27 power units with voltage inverters.

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