RU1823128C - Independent power system of stable frequency - Google Patents

Abstract

Usage: the power system can be used as a power source for consumers requiring a stable frequency at a variable frequency of the main network. SUMMARY OF THE INVENTION: by introducing a sinusoidal voltage converter into rectangular pulses into a power system, by special design of semiconductor switches, by connecting nonlinear targets to them with current sensors in each, by special design of the control unit and by connecting the windings of an electric machine frequency converter according to a certain law, improve output voltage quality. 5 ill., 4 tab.

Description

The invention relates to electrical engineering and can be used as a power source for consumers who need to stabilize the frequency of the output voltage at a variable speed of the generators.

An object of the invention is to improve the shape of voltage and load current curves.

Figure 1 shows a schematic diagram of an autonomous power system with a stable frequency; Fig. 2 is a timing diagram illustrating the operation of the device (diagrams are shown for the first phase); Fig. 3 is a functional diagram of a control unit; Fig. 4 is a circuit diagram of a sinusoidal voltage to square wave converter; Fig. 5 is a timing chart illustrating the operation of a sinusoidal voltage to square wave converter.

The self-contained stable frequency power system comprises a generator 1 made in the form of two electric machine converters 2, 3 of frequency, the rotors of which are rigidly connected to each other and with a drive motor not shown, three three-phase semiconductor switches 4, 5, 6. a three-phase source of 7 voltage of a fixed frequency and a three-phase load 8, and the root winding 9 of the first electric machine frequency converter 2 is made in the form of three sections 10,11,12, laid in the same grooves with a shift of each phase in sections 10-12 by 120 electrically degrees relative to each other, the beginning of the first ai, second bn and third si phases of the first 10 (second 11, third 12) sections of the first electric machine converter 2 is connected to the first (second, third) inputs of the first 4, second 5 and third 6 semiconductor switches, a winding 13 excitement

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00

N) cj

GO

oo

the first electric machine converter 2 is connected to a fixed frequency voltage source 7 with reverse phase rotation relative to the excitation winding 14 of the second electromyline converter 3, the root winding 15 of the second electric machine frequency converter 3 is also made in the form of three sections 16, 17, 18, laid in one and the same grooves with a shift of each phase in sections 16-18 by 120 electrical degrees relative to each other, the ends of the phases of sections 10-12 of the root winding 9 of the first electrical machine converter 2 are connected to the beginning the phases of sections 16-18 of the root winding 15 of the second electric machine converter 3, and in the first sections 10 and 16 the first an, an, the second on, bi2 and the third en, C12 phases are interconnected, the first sections 11 and 17 are the first 321 with the third C22, the second D21 with the first 322 and the third C21 with the second D22, in the third sections 12 and 18 - the first aai with the second bz2, the second bz1 with the third sz2 and the third sz1 with the first az2 phases, and the ends of the phases

312. bl2. C12, 322, U22, C22, 332, bz2, C32 COOTV6T-

Actually, in each section 16-18 of the second electric machine converter 3 are combined into a star, each semiconductor converter 4-6 is made in the form of a three-phase diode bridge with diodes 19-24, 25-30, 31-36, respectively, the outputs of which are shunted by two according to the included parallel to the chains, each of which consists of two series-connected thyristors and two current sensors 37, 38, 53 and 39, 40, 55, 56; 41, 42, 57, 58, and 43, 44. 59, 60; 45, 46, 61. 62 and 47, 48. 63, 64, respectively, the three-phase load 8 is made separate into two identical sections 49, 50. magnetically coupled to each other, with the beginning of each phase A1, B1, C1 of the first load section 49 8 are connected to a common junction point of thyristors 37, 38; 41.42; 45, 46, respectively, of each semiconductor switch 4-6, and the ends of phases A1, B1, C1 of the first section 49 of the load 8 are connected in a star, the ends of each A2, B2, C2 of the second section 50 of the load 8 are connected to a common connection point of the thyristors 39, 40; 43.44; 47, 48, respectively, of each semiconductor switch 4-6, and the beginning of phases A2, B2, C2 of the second section 50 of load 8 are combined into a star. The self-contained power system also contains a sinusoidal voltage converter 51 to rectangular pulses, the inputs of which are connected to the beginning of the phase, bii.cn, 321, b21, C21 of the root winding sections 10 11 of the first electric machine converter 2 frequencies, and the outputs are connected to the main the information input of the control unit 52, consisting of two identical parts 65, 66 (Fig. H), the additional information inputs of the control unit 52 are connected to the load current sensors 53-64, the outputs of the control unit 52 are connected to the control electrodes tiris tori 37-48.

The sinusoidal voltage converter 51 to square pulses (Fig. 4) consists of four three-phase circuits 67, 68, 69 and 70, each phase dn,. dsi: dii, d2 i, da i and en, 621, eai; en, 621, 631 of which is a series-connected diode and resistor, respectively 71 and 77, 72 and 78, 73 and 79, 89 and 83, 90 and 84, 94 and 88, three-phase circuits 67, 69 and 68, 70 are combined into two three-phase bridges 104, 105, the loads of which are ballasts 95 and 96, respectively, with one of the phases dn and e1 of each bridge having an electronic key 97 and 98, respectively, potentially isolated from the converter 51, electronic key outputs 97 and 98 of each bridge connected to the inputs of the element 103 2I, the output of which is the output of the Converter 51, the output of the converter 51 is connected to the information inputs of blocks 65.66, namely, to the first input of the first element 99 2I (Fig. 3), and the inputs of the second, third, fourth elements 100-102 2I are designed to connect sensors 53, 54, 57, 58 , 61, 62 of the load current (Fig. 1) and the inputs of the elements 100-102 2I are connected to all inputs of the element 107 6IL AND NOT and with the first inputs of each of the six elements 108-113 ZILI NOT, the outputs of the elements 100-102 2I are connected with all three inputs of the ZILI-NOT element 106, the output of which is connected to the second inputs of the ZILI-NOT elements 108-113, the element output 107 6OR-NOT connected to the third inputs of all six elements 108-113 ZILI-NOT and to the second input of the first element 99 2I, the output of which is connected to the first inputs of all four elements 114-117 2OR, the outputs of the second, third, fourth and fifth elements 109-112 ZILI-NOT connected to the second inputs of all elements 114-117 2OR, respectively, the outputs of which, as well as the outputs of the first and sixth elements of ZILI-NOT 108, 113 are designed to be connected to the control electrodes of thyristors 37. 38, 41, 42, 45, 46.

Autonomous power system of stable frequency operates as follows.

Since the excitation windings 13, 14 of three-phase machine converters 2, 3 are connected to the source 7 on Em Sln (0) lsln a) Ht-cos (W6t Em Sin (UHt-Em Sln ((O voltage of a fixed frequency with reverse phase rotation in relation to to each other, the rotation of the fields created by them is carried out in the opposite direction.Then at the outputs of all phases of the root windings 9, 15 connected to each other, the total emf are induced:

baa ba12 + 6a11 Em Sln ftJHt.COS 0) 6t;

ed ™ eb22 + eb22 + bc21 em-sln (yHt- 120 °) .cos

ecA-ec32 + eb3i Em-sln (w Ht-240 °) .cos OJ6t;

 + e11 Em sln a Ht.cos (with 6t- 120 °):

eb eC22 + ea2i Em -sln (a) „t-120 °) .cos (6U6t-120 °);

CcB 6a32 + 6s31

240 °) -cos (W6t-120 °):

eac eC12 + ecii Em 240e);

etc ea22 + eb21 120 °). cos (u 6t-240 °);

ecc ez2 + eaz1 240 °) .- cos (W6t-240 °), where eadves is the total emf of the corresponding phases;

eai iess3 - EMF of the corresponding phases

first car 2;

еа12ес32 - EMF of the corresponding phases

second machine 3;

Em is the amplitude value of the EMF; Cn a carrier voltage frequency; o b - voltage beat frequency. Figure 2a shows the EMF curves for phase A1, the EMF curves of phases B1 and C1 are offset by 120 electrical degrees, respectively, from phase A1 and one relative to the other.

In the initial state, the currents in phases A1, B1 and C1 of the load 49, and, therefore, in the sensors 53 and 54, 57 and 58, 61 and 62 of the load current are zero. In this case, zero signals are present at all inputs of the second 100, third 101 and fourth 102 elements 2I, element 107 6 OR NOT and at the first inputs of all six elements 108-113 ZILI NOT, At the inputs of the second 100, third 101 and fourth 102 elements 2I and at all inputs of the ZILI element 106 there are also zero signals, which provides a zero signal at the input of the ZILI element 106 and, accordingly, at the second inputs of all six ZILI-NOT elements. At the output of element 107 6 OR is NOT present a single signal that is fed to the second input of element 99 2I and to the third inputs of all six elements 108-113 ZILI NOT, which provides zero signal signals at the outputs and, accordingly, at the second inputs of all four Items 114-117 2 OR.

Voltage beats come from two sections of the generator 9 to the inputs of the pre-cut 5 bodies 51 of the sinusoidal voltage into rectangular pulses. In the phases dn, d2i, dat and en, 621. ez1. respectively, the chains 67 and 68 are allocated to the carrier frequency shown in figa and 56, and on

0, Fig. Ba shows the voltages: lines without icons are phase 11, d 12; lines with a dash - in phases bi2. bit lines with a cross - in phases ci2, cii; on Fig, respectively, in phases 321, C22; in the phases b21. d22: in phases C21.

5 D22. In this case, the electronic key 97 in the dn phase of the chain 67 will open at the moments shown in Fig. Bb, and the keys 98 in the eai phase of the chain 68 will open at the times shown in Fig. 5g. Key Output Pulses

0, the elements 103 2I enter the inputs, the output of which is fed to the information input of the control unit 52 (Fig. 5e). In this case, at the output 107 of the 6YLE-NOT element and at the second input of the first element 99 2I, single signals are present, and at the output of the element 99 2I, single signals appear at the same time as the output of the sinusoidal voltage converter 51

0 rectangular pulses. This ensures the appearance of single signals at the first inputs and outputs of all four elements 114-117 2 OR and on the corresponding control electrodes of the thyristors

5 38, 41, 42, 45. Thus, at start-up, two thyristors 41.42 are switched on in no more than one load phase 8, in this case phase B, and one thyristor 38 and 45, respectively, in the other two

0 phases A and C of load 8. Block 66 works similarly, providing control signals on thyristors 40, 43, 44, 47. When current appears in load 8, the first harmonic of which is shown in Fig.2b for

5 phases A1 and A2, at least one of the load current sensors 53-64 is triggered, as a result of which a single signal appears at one of the inputs of element 6 6-NOR, and a zero signal appears at its output,

0 which goes to the second input of the first element 99 2I, locking it for pulses from the converter 51 and to the first inputs of all six elements 108-113 ZILI-NOT, removing the ban on control from the sensor

5 53-64 load current. During one period of the low-frequency modulating voltage, the control signals are supplied to the thyristors 37-48 in accordance with the diagrams shown in figv, 2g, in which the shaded sections show the time intervals in which

corresponding pairs of thyristors are included, and the signals in FIG. 2c are 180 ° shifted relative to the signals in FIG. 2d. The setpoint value of 1st sensors 37-48 of the load current may lie in the range (1.2-2) 1ud Set 0.5lm. where beats is the holding current for this type of thyristors, im is the amplitude of the load current. .

The thyristors are turned on as shown in tables 1-4. and At the moments when the load current passes through zero, the switching of thyristors and diodes occurs according to Tables 2 and 3.

At the moments when the load current passes through zero, the switching of the thyristors occurs automatically as shown in Table 4.

As a result of such natural switching of thyristors 37-48 and diodes 19-36 of semiconductor switches 4-6 on the first section 49 of load 8, the voltage appears: in phase A1 - UAI (fig.2d), in phase B1 - UBL similar to phase A1 but shifted by 120 electrical degrees in phase C1 to Uci, is similar to phase A1, but shifted by 240 electrical degrees and currents will flow through the phases of the first section, the first harmonic of which for phase A1 is shown in Fig. 26. In the second section 50 of load 8, the voltage appears: in phase A2 - UA2 (fig.2d), in phase B2 - UB, similar to phase A2, shifted by 120 electrical degrees, in phase C2 - Uc2, similar to phase A2, but shifted by 240 electrical degrees, and currents will flow through the phases of the second section 50, the first harmonic of which for phase A2 is shown in Fig. 26.

Claims (1)

SUMMARY OF THE INVENTION A self-contained stable frequency power system comprising a machine-valve generator made in the form of two three-phase electromachine frequency converters arranged on one shaft, three three-phase semiconductor switches, a three-phase voltage source of a fixed frequency and a three-phase load connected to the outputs of the switches, the root winding being the first frequency converter, made in the form of three sections located in the same grooves of the core with a shift of each phase in the section x at 120el. hail, phase start of each section of the first frequency converter connected to the power inputs of the corresponding switch, the control inputs of which are connected with the outputs of the control unit having information an input, while the three-phase inductor windings of the converters are connected to the terminals of a fixed frequency source with the phases of one winding reversed in relation to the other, characterized in that, in order to improve the quality of the output electricity, a sinusoidal voltage converter into rectangular pulses is additionally introduced, each semiconductor The switch is made in the form of a three-phase two-half-bridge, to the DC output of which two parallel-connected circuits are connected, each of which consists of two in series thyristors turned on and two current sensors connected to each thyristor so that the current sensors in each circuit have a common point, the switch control unit is equipped with additional information inputs connected to the outputs of the current sensors, the main information input of the switch control unit is connected to the output of the sinusoidal signal converter, whose inputs connected to the phase beginnings of the first and second sections of the root winding of the first frequency converter, the root winding of the second frequency converter is arranged to fit in the grooves of the core in the same way the main winding of the first frequency converter, the ends of the phases in each section of the second frequency converter are connected to a star, and the phases of the same sections are connected to the ends of the phases of the corresponding sections of the primary windings of the first converter, in the first section with the same phases, in the second section the first phase from the second phase, the second phase with the third phase, the third phase with the first phase, and in the third section the first phase with the third phase, the second phase with the first phase, the third phase with the second phase, and the load is made of two magnetically connected three-phase windings, one of which is combined the beginning, and at the other - the ends of the windings, and other outputs of the same phases of the windings are connected to a common point of the current sensors of the same semiconductor switch. table 2 Table 4 T7G7G  l- muptfcnropctf 37-4, // P. "If S v  - 4 $ V: / tr f4 vi s: 4 | hours 0 / P UCWuMUtV ffUPNl / A, HQnpS XPNUU r- 0m maw sensors S3.SV, S7.58, 6 /. 62 51 l || IIII1- P t g -1 t t s. Kulra & nachin elekmrobsh mchrispgorob . 37.38.4, 42.45.46 -TN SU r cg - 3 h 5: / g to the valve switch i / i in Ј If e fr Ј «c  ON.-H .. A -N lch - / h H ± S / -, L-ifa -J Z L / LJ w. . . S $ . 5 5 g egt YaRag.Zd