RU109935U1 - MATRIX CASCADE FREQUENCY CONVERTER WITH WIDTH-PULSE MODULATION OF OUTPUT VOLTAGE - Google Patents

Abstract

 1. Matrix cascade frequency converter with pulse-width modulation (PWM) of the output voltage, consisting of power transformer equipment, a converter part containing in each m-phase n cascades (matrices) of bridge 3-phase circuits on fully controlled keys of IGBT modules with double-sided conductivity, and microprocessor control system, characterized in that the cascades of bridge 3-phase circuits are connected in pairs to potentially isolated secondary windings of [(m · n) / 2k] transformers, one of which is connected star ", and another -" triangle ", where the k - the number of pairs of secondary windings on each transformer. ! 2. The utility model according to claim 1, characterized in that in the design of the converter part, volumetric installation of its elements is used in combination with a distributed forced air cooling system of IGBT modules.

Description

1. The technical field to which the utility model belongs.

This utility model relates to the field of semiconductor converting technology, in particular, to direct frequency converters (NFC) for regulating high-voltage AC electric motors of high power.

2. The prior art. A control device for a 3-phase two-link LPC based on fully controllable keys of IGBT modules with two-side conductivity using the software method of high-frequency adaptive pulse-width modulation (PWM), described, for example, in [1; 2].

The two-link low-frequency converter on IGBT modules with high-frequency PWM has a drawback due to the presence of two links in the conversion circuit, which leads to additional power losses and to a decrease in efficiency.

The closest in technical essence to the claimed utility model is a device according to the matrix cascade NPC scheme described in [3] (prototype). In this converter, each cascade is built on fully controlled keys of IGBT modules with two-sided conductivity, connected in the form of a matrix in a 3-phase bridge circuit. The output voltage is generated by summing the voltages of individual stages using the software method of high-frequency sinusoidal PWM when powered from potentially isolated secondary windings of a multi-winding transformer.

In the specified 900 kW low-frequency drive, the power converter section in a modular design combined with a centralized forced air cooling system, one multi-winding transformer and control system are located in cabinets with a total overall size of 2900 × 3400 × 1200 and weighing 4800 kg.

3. Disclosure of a utility model.

The proposed utility model of a matrix cascade frequency converter (MFC) with a high-frequency sinusoidal PWM output voltage, made according to a scheme similar to the prototype [3], provides a reduction in overall performance compared to it due to a more rational structural design of the components of the power unit while maintaining high parameters of power quality both from the supply network and the motor side [4].

The indicated technical result is achieved by using the elements of the volumetric mounting of the elements in the cabinets of the volumetric installation in combination with a distributed forced air cooling system, as well as by reducing the unit power of the transformers with a corresponding increase in their number when placed separately relative to the cabinets of the power converting part.

4. A brief description of the drawings.

The inventive utility model is illustrated in the drawing (Fig. 1), which shows a block diagram of the proposed 4-stage matrix frequency converter with pulse-width modulated (PWM) output voltage, each stage (matrix) of which is built on fully controlled keys of IGBT modules with two-sided conductivity according to the bridge 3-phase circuit.

Figure 2; 3 presents drawings of general views of the power cabinet of the converter part of the said MCPC with a power of 1000 kW, showing the layout of its structural elements.

Figure 4 shows the appearance of the power cabinets and the cabinet of the control system of the prototype of the proposed utility model.

5. Implementation of a utility model.

Matrix n-cascade frequency converter with PWM output voltage (Fig. 1) consists of m (A, B, C) phases of the power unit 1 and microprocessor control system (SU) 2 with fiber optic communication lines (FOCL) 3.

Each phase of the power part 1 consists of n cascades of bridge 3-phase circuits (matrices) 4, the inputs of which through vacuum contactors 5 are connected in pairs to potentially isolated secondary windings of [(m × n) / 2k] transformers 6, one of which is connected star ”, and the other -“ triangle ”, where k is the number of pairs of secondary windings on the transformer. In addition, one of the pairs of bridge circuits 4 at the input is electrically connected to two voltage sensors 7.

Both outputs of the bridge circuits 4 of each phase are connected in series - according to one of which is brought out through the phase current sensor 8, and the other is connected to a common point with neighboring phases.

The outputs of the sensors 7; 8 are connected to the boards of the optical converters 9, which in turn are connected via the FOCL 3 channels to the microprocessor control system 2. The latter via the FOCL channels 3 is connected to the boards of the optical signal converters 10, which in turn are connected via the FOCL channels 3 to the boards of the driver devices 11 IGBT modules 12.

Structurally, the power part 1 of the MKPCH, except for [(m × n) / 2k] transformers 6, which are located separately, is located in 3 - according to the number of output m phases (A, B, C) - standard cabinets with dimensions of 2000 × 800 × 800 and weighing 383 kg (Fig.2, 3).

Inside each cabinet there are three vertical panels 13; 14 of non-combustible fiberglass, two of which 13 are IGBT modules 12 of bridge circuits 4, and on the third front panel 14 there are boards of optical converters 9 (Fig. 3), optical signal converters 10, secondary power supplies and other elements.

On each of the vertical panels 13 with IGBT modules 12 (FIG. 2), two cascades of bridge circuits 4 and two contactors 5 are placed. Directly above the housings of the IGBT modules 12 are driver device boards 11. On the same side of the panels 13 are also located voltage sensors 7 and current 8.

On the reverse side of the panels 13, radiators 15 are installed for individual air cooling of IGBT modules 12. Radiators 15 are pairwise enclosed in ventilation ducts, each of which has one fan 16. Moreover, cold air is taken from the side channels, and the heated air is output middle channel of a distributed forced air cooling system.

On the front side of each cabinet on the door 17 installed devices of local control, parameter control and alarm.

SU 2 is structurally placed in one standard cabinet with dimensions 2000 × 600 × 800 and a weight of 92 kg.

The proposed utility model of the IHRC works as follows.

According to the signal from the microprocessor control system 2 (Fig. 1), the contactors 5 are turned on and the transformers 6 are supplied with power to the inputs of the bridge circuits 4 of each stage. At the same time, the control optical signals via FOCL 3 channels are received from the control system 2 to the boards of the opto-signal converters 10 for their replication and further transmission to the boards of the driver devices 11 of the IGBT modules 12 (Fig. 2) of the bridge circuits 4 of each cascade.

Driver devices 11 convert the optical signals and generate electrical control pulses for switching on and off according to a given algorithm of keys of IGBT modules 12 at the shoulders of bridge circuits 4 while ensuring their protection from maximum currents.

Electrical analog signals about the current state of the MCPC, coming from the voltage sensors 7 and currents 8 (Fig. 1) to the optical converter boards 9, are converted into digital optical signals and transmitted via FOCL 3 cables to the microprocessor control cabinet 2.

Further, on the basis of the received information, SU 2 generates the necessary algorithms for controlling opto-signals to provide rectification modes in bridge circuits 4 with a control angle α equal to zero and with a duration of allowed opening of keys equal to (120 ° + γ) e., Where γ - the angle of switching at the frequency of the mains, while high-frequency sinusoidal PWM output voltage [4].

The output voltages of the bridge circuits 4 of each n-th stage with a given algorithm for turning their respective arms on and off are summed up, providing the necessary level and quality parameters of the voltage at the MFC output in the sinusoidal PWM mode. Next, the total voltage of the n-stages of each m-phase is fed through current sensors 8 to the output terminals of the MFC.

The proposed utility model is implemented in the form of a prototype matrix 4-stage cascade frequency converter with a high-frequency sinusoidal PWM (Fig. 4), designed to control a high-voltage high-power rowing electric motor in electric propulsion systems of promising large-capacity vessels.

Literature.

1. Device and method for controlling a reversible converter of AC energy into AC energy. Shreiner R.T., Efimov A.A. and other RF Patent No.RU 2265947 C2 class. Н02М 5/27 from 07/09/2002.

2. The method of frequency conversion. Shreiner R.T., Krivovyaz V.K. and other RF Patent No.RU 2269860 C2 class. Н02М 5/16 from 09.16.2003.

3. Matrix cascade frequency converter type CIMR-MX1S on IGBT modules with high-frequency PWM and with energy recovery for a high-voltage AC drive with a capacity of up to 6.0 MVA. Prospectus of the company "Yaskawa Electric Corporation" (Japan), 2007

4. The device for forming and regulating the voltage of the matrix direct frequency converter with a high-frequency sinusoidal PWM. Skvortsov B.A., Vasin I.M. and other Application No. 201029681/07 of 07.15.2010. (Decision of the Federal Service of ROSPATENT on the grant of a patent for an invention No.2012929681 / 07 (042187) dated 02.02.2011).

Claims (2)

1. Matrix cascade frequency converter with pulse-width modulation (PWM) of the output voltage, consisting of power transformer equipment, a converter part containing in each m-phase n cascades (matrices) of bridge 3-phase circuits on fully controlled keys of IGBT modules with double-sided conductivity, and microprocessor control system, characterized in that the cascades of bridge 3-phase circuits are connected in pairs to potentially isolated secondary windings of [(m · n) / 2k] transformers, one of which is connected star ", and another -" triangle ", where the k - the number of pairs of secondary windings on each transformer. 2. The utility model according to claim 1, characterized in that in the design of the converter part, volumetric installation of its elements is used in combination with a distributed forced air cooling system of IGBT modules.