WO1996002084A1 - A universal converter device with an impulse sequence in the shape of a cosine wave - Google Patents
A universal converter device with an impulse sequence in the shape of a cosine wave Download PDFInfo
- Publication number
- WO1996002084A1 WO1996002084A1 PCT/IT1994/000106 IT9400106W WO9602084A1 WO 1996002084 A1 WO1996002084 A1 WO 1996002084A1 IT 9400106 W IT9400106 W IT 9400106W WO 9602084 A1 WO9602084 A1 WO 9602084A1
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- WIPO (PCT)
- Prior art keywords
- phase
- converter device
- universal converter
- cosine
- wave
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/02—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc
- H02M5/04—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters
- H02M5/22—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M5/25—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
- H02M5/27—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means for conversion of frequency
Definitions
- the present invention concerns a universal converter device with an impulse sequence in the shape of a cosine wave.
- the prior art shows converter devices that generate differentiated wave shapes like sinusoidal waves, square waves, impulse period waves, alternate current waves, fix or variable waves, and waves with reversible and non reversible polarity.
- the converter according to the present invention transforms the elecric energy of the single-phase or three-phase network into a bipolar or alternate tension, from zero to the network frequency, on differentiated kinds of loads, as motors of any kind and with any number of phases, while halving the SCR number it may become single-phase.
- the device according to the present invention allows to change the speed of any kind of motor; it may be applied to earth and sea traction, to trains, funiculars, tramways and trolley bus lines, undergrounds, electric vehicles and ships.
- a further application of the device according to the present invention is the one of frequency changer for induction ovens, welding machines, electric lines, resonant circuits, transformers, condensers, coils and similar.
- Figure 1 shows a scheme of a converter device from a three-phase to a bipolar with a counter CO with three outlets.
- Figure lb shows a device according to the present invention with a counter CO with six outlets.
- Figure lc shows a double device according to the present invention with a counter CO with twelve outlets.
- Figure 2 shows in a scheme the functioning of the device according to the present invention, where F2 changes and the cosine wave is produced.
- Figure 3 shows a variant of a scheme that determines a reduction of the average outlet tension, changing the phase of the system to 60°.
- Figure 4a shows a circuit with an impulse sequence where, when the phase-displacement of the positive and negative impulses ⁇ ⁇ changes, also the phase of the system changes.
- Figure 4 shows how even if varying ( Oi. , ⁇ S does not change.
- Figure 5 shows a variant in which if the phase Fl varies, the average outlet tension EM does not change if the outlet period T is equal.
- Figures 6a and 6b show two variants of a device with three separate systems with independent variable phases.
- the universal converter device with impulse sequence in the shape of a cosine wave according to the present invention may make use of phase shifters P or, for obtaining a greater precision and for supplying the SCR a sequence of impulses having the same distance in time, it may make use of counters CO or similar, that have the same function of the phase shifters.
- a partial converter CP consisting of amplifyiers, polarity inverters, period circuits and circuits of the ignition impulse , modulators , decoders , logic circuits , load, transformers for the SCR and other;
- a shifter of the system f> S that shifts the ignition impulses in time so that the circuit varies the average outlet tension EM changing the phase of more or less 180° or 360°, thus determining also the polarity of the circuit.
- the generator may be a PL ( Phase Locked Loop) or similar.
- the generator G multiplies or devides Fl, always with the same PLL or similar, so that if F2 is smaller than Fl the outlets A, B and C of CO vary with respect to Fl, and thus an average tension wave is produced with a wrapper of truncated sinusoid portions, of the cosine kind of period T, while if F2 becomes even smaller, F3 diminishes and if F2 becomes equal to Fl, a wave equal to those obtained with the variants of the figures la, lb and lc is obtaine .
- non sinusoidal wave shapes may be obtained, useful with inductive loads, for a quicker increase of the current intensity, or for capacitive loads, for limiting the initial current with an overturned cosine wave.
- EM may be increased, changing the period of the ingition impulse.
- the device according to the present invention shown in figure 3, allows a reduction of EM changing S to 60°, but in such case, due to the range limitation, EM does not go to zero and the system phase can not be adjusted; on the other hand, for changing EM from zero to the maximum, using also 0 S , the ignition moment must be limited to the area of the positive or negative half-wave.
- phase shifters or other circuits may be used it is easier and safer to obtain the aim set forth by means of a circuit with impulse sequence, as shown in figure 4a.
- M is a PLL or similar that has the only task of multiplying Fl according to the kind and the number of outlets of counter CS (which may be a decoded counter, a shift register or similar) .
- phase shifters there is no need of phase shifters and of electronic or. thermic drifts, which define the ignition times of the scRs; the only phase shifter used works with a closed ring feeding as shown in the variants of figures la, lb, lc, 4a, 4b, etc.; the circuit may be very stable, comprising the one with an open ring;
- said device may work also in an asynchronous manner (G independent from Fl); the phase can not be adjusted, but the same waves are formed;
- said device may adjust the converted phase F3 in anticipation or in delay varying 0 S , as shown in figures 3, 4, ... etc; the variation is inversely proportional; the phase varies also with oC , but it is directly proportional (EM decreases);
- the power may be adjusted in three ways: with £> S, with D or with ⁇ * ;
- the cosine ( D of the system may be near to 1; the reactive consumption may also become variable, and this is valid for the relation converter-load as well as for the relation converter-net (in three-phase and in two-phase circuits).
- converters may be realized following to the described principles according to the present invention: one-phase, two-phase, three-phase, star-triangle, delta, with the load behind the converter or between the converter and the net, with (poligonal) interlock, with short-circuit reactors, with or without circulation current, etc.
- TRIACs may be used and also motors with double or triple star.
- the ignition of the electronic switches is different: a sequence of equidistant impulses, more or less delayed in time, for forming variable frequences of the cosine kind; in nearly all of them it is possible to adjust the phase, the frequence, the polarity, the power and also, where desired, the cosine ⁇ and the shape of the wave, and due to said features the device according to the present invention is a universal one.
- inductive motors and generators with electric lines may be considered.
- the motor may work in the four faces; - it has a couple stable at the low speeds for many impulses/revolution;
- the motor may perform reverse revolutions if only F2 is changed
- the motor works like a synchrone motor, without the known limitations in costs, weight, fields' excitation, loss of synchronism, etc;
- a generator for electric lines may change its speed also at a high speed, and a plurality of coupled generators may vary their frequency and phase, while the general phase, the line frequency and the general power are maintained, even between two different systems as in the international electric lines; furthermore, it may vary also the phase relation between the same phases of a two-phase or a three-phase, as shown in the schemes of figures 6.
- the cosine may be adjusted without intervening in the excitation of the generator
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Ac-Ac Conversion (AREA)
Abstract
The universal converter device with an impulse sequence in the shape of a cosine wave, transforms the electric energy of the one-phase or three-phase net into a bipolar or alternate tension in the shape of a cosine, with a variable one-phase, two-phase or three-phase frequency, from zero to the net frequency, on differentiated loads, making use of phase shifters (P) and/or counters (CO) for defining the ignition moment (α).
Description
"A UNIVERSAL CONVERTER DEVICE WITH AN IMPULSE SEQUENCE IN THE SHAPE OF A COSINE WAVE"
The present invention concerns a universal converter device with an impulse sequence in the shape of a cosine wave.
The prior art shows converter devices that generate differentiated wave shapes like sinusoidal waves, square waves, impulse period waves, alternate current waves, fix or variable waves, and waves with reversible and non reversible polarity.
Said already existing devices show considerable disadvantages as they are expensive, complex, limited in their functioning and/or in their power, and have components that are of difficult availability and maintenance.
It is the aim of the present invention to solve above mentioned inconveniences by means of a universal converter device with an impulse sequence in the shape of a cosine wave, realized with simple and widely- circulated electronic components, without any limitation in power and high efficiency, as the conversion is direct.
The converter according to the present invention transforms the elecric energy of the single-phase or three-phase network into a bipolar or alternate tension, from zero to the network frequency, on differentiated kinds of loads, as motors of any kind and with any number of phases, while halving the SCR number it may become single-phase.
The device according to the present invention allows to change the speed of any kind of motor; it may be applied to earth and sea traction, to trains, funiculars, tramways and trolley bus lines, undergrounds, electric vehicles and ships.
A further application of the device according to the present invention is the one of frequency changer for induction ovens, welding machines, electric lines, resonant circuits, transformers, condensers, coils and similar.
The present invention will be described more in detail hereinbelow relating to the enclosed drawings in which some embodiments are shown.
Figure 1 shows a scheme of a converter device from a three-phase to a bipolar with a counter CO with three outlets.
Figure lb shows a device according to the present invention with a counter CO with six outlets.
Figure lc shows a double device according to the present invention with a counter CO with twelve outlets.
Figure 2 shows in a scheme the functioning of the device according to the present invention, where F2 changes and the cosine wave is produced.
Figure 3 shows a variant of a scheme that determines a reduction of the average outlet tension, changing the phase of the system to 60°.
Figure 4a shows a circuit with an impulse sequence where, when the phase-displacement of the positive and negative impulses ψ < changes, also the phase of the system changes.
Figure 4 shows how even if varying ( Oi. , ψS does not change.
Figure 5 shows a variant in which if the phase Fl varies, the average outlet tension EM does not change if the outlet period T is equal.
Figures 6a and 6b show two variants of a device with three separate systems with independent variable phases.
Figures 7a, 7b, 7c, 7d, 7e, 7f and 7g show schemes of variants of the device according to the present invention, with a converter number respectively P=3, P=6, P=12, P=l, two-phase with P=2 from two phases to two phases, two-phase with P=2 from two phases to three phases, P=l and P=2 from one phase to three phases, and P=l from one phase to three phases.
Relating now to the details of the enclosed figures, while the known converters make use of phase shifters, i.e. circuits consisting of linear ramps, comparators and other for defining the ignition moment O and have thermic and electronic drifts and need setting, the universal converter device with impulse sequence in the shape of a cosine wave according to the present invention may make use of phase shifters P or, for obtaining a greater precision and for supplying the SCR a sequence of impulses having the same distance in time, it may make use of counters CO or similar, that have the same function of the phase shifters.
Relating to figure la the device according to the present invention comprises a converter P=3 from three-phase to two-phase with:
- a partial converter CP consisting of amplifyiers, polarity inverters, period circuits and circuits of the ignition impulse , modulators , decoders , logic circuits , load, transformers for the SCR and other;
- a generator G synchronized with the net frequency Fl that multiplies said frequency by three generating F2 and sends impulses to a counter CO with three outlets A, B and C, that reach three SCR with impulses fix in time with respect to Fl and therefore EM does not vary, while it changes when F2 changes.
- A shifter of the system f> S that shifts the ignition impulses in time so that the circuit varies the average outlet tension EM changing the phase of more or less 180° or 360°, thus determining also the polarity of the circuit.
In a variant according to the present invention, the generator may be a PL ( Phase Locked Loop) or similar.
In the variant of figure lb the device according to the present invention shows P=6 , and in this case the counter CO has six- outlets, while in figure lc the
double-bridge device has P=12 and CO has therefore twelve outlets.
Relating to figure 2, the generator G multiplies or devides Fl, always with the same PLL or similar, so that if F2 is smaller than Fl the outlets A, B and C of CO vary with respect to Fl, and thus an average tension wave is produced with a wrapper of truncated sinusoid portions, of the cosine kind of period T, while if F2 becomes even smaller, F3 diminishes and if F2 becomes equal to Fl, a wave equal to those obtained with the variants of the figures la, lb and lc is obtaine .
If, however, F2 is greater than Fl, the same overturned cosine kind wave is obtained.
In such variants non sinusoidal wave shapes may be obtained, useful with inductive loads, for a quicker increase of the current intensity, or for capacitive loads, for limiting the initial current with an overturned cosine wave.
In the possible variants EM may be increased, changing the period of the ingition impulse.
The device according to the present invention, shown in figure 3, allows a reduction of EM changing S to 60°, but in such case, due to the range limitation, EM does not go to zero and the system phase can not be adjusted; on the other hand, for changing EM from zero to the maximum, using also 0 S , the ignition moment must be limited to the area of the positive or negative half-wave.
Even if phase shifters or other circuits may be used it is easier and safer to obtain the aim set forth by means of a circuit with impulse sequence, as shown in figure 4a.
«J,*t performs this shifting; M is a PLL or similar that has the only task of multiplying Fl according to the kind and the number of outlets of counter CS (which may be a decoded counter, a shift register or similar) .
If, for obtaining a complete CS-cycle, six impulses are requested, M must be multiplied by six; CS delimits the outlets A, B and C according to the shifting of by means of logic circuits.
The advantages and the functional features of the universal converter device with an impulse sequence in
the shape of a cosine wave, may be described as follows: one single synchronization with the net is sufficient, as shown in figure lc (whereas in a converter with a double bridge, P=12, twelve synchronizations of the star-triangle transformers are needed);
- there is no need of phase shifters and of electronic or. thermic drifts, which define the ignition times of the scRs; the only phase shifter used works with a closed ring feeding as shown in the variants of figures la, lb, lc, 4a, 4b, etc.; the circuit may be very stable, comprising the one with an open ring;
- said device may work also in an asynchronous manner (G independent from Fl); the phase can not be adjusted, but the same waves are formed;
- however, said device may adjust the converted phase F3 in anticipation or in delay varying 0 S , as shown in figures 3, 4, ... etc; the variation is inversely proportional; the phase varies also with oC , but it is directly proportional (EM decreases);
- the power may be adjusted in three ways: with £> S, with D or with ψ * ;
- it is possible to structure the circuits in different manners, as shown in figure 4a: varying^ø^ also ψ S changes; in figure 4b, if ψOL is changed,©s does not change;
- it may change the phases of a system, which are independent from each other;
- even if F3 consists of shifted portions of truncated sinusoids, the cosine (D of the system may be near to 1; the reactive consumption may also become variable, and this is valid for the relation converter-load as well as for the relation converter-net (in three-phase and in two-phase circuits). In one-phase converters P=l or P=2, it is valid only between the converter and the load; the load, from the point of view of EM, is always balanced, even if F3 is high, as a sharing out of the same intensity I is possible in time and in the three phases;
- it may generate, beyond the wave in the shape of a cosine, other kinds of waves, even if it is not its natural condition, as by modulating the different parameters, an incline may be realized that comes near to the integral of any curve;
- the functions F2- *F3 and (2$S-^ F3 are linear; the function
is of the cosine kind.
Of course, many kinds of converters may be realized following to the described principles according to the present invention: one-phase, two-phase, three-phase, star-triangle, delta, with the load behind the converter or between the converter and the net, with
(poligonal) interlock, with short-circuit reactors, with or without circulation current, etc.
TRIACs, SCRSs, as well as diodes and SCRs, may be used and also motors with double or triple star.
According to the present invention, the ignition of the electronic switches is different: a sequence of equidistant impulses, more or less delayed in time, for forming variable frequences of the cosine kind; in nearly all of them it is possible to adjust the phase, the frequence, the polarity, the power and also, where desired, the cosine < and the shape of the wave, and due to said features the device according to the present invention is a universal one.
For what concerns the functioning of possible applications of the device according to the present invention, for inductive loads, and similarly for capacitive loads in which only the sign changes, induction motors and generators with electric lines may be considered.
In the case of an induction motor, working with three net phases and three internal phases: - the motor may work in the four faces;
- it has a couple stable at the low speeds for many impulses/revolution;
- the harmonics are low, corresponding to 1/N, where N describes the number of impulses per second:
- the motor may perform reverse revolutions if only F2 is changed;
- the motor works like a synchrone motor, without the known limitations in costs, weight, fields' excitation, loss of synchronism, etc;
- the cosine Cx° is high at high converter-net intensities I, and the compensation of the low cosine ( value at low speeds occurs.
A generator for electric lines, provided with the device according to the present invention, may change its speed also at a high speed, and a plurality of coupled generators may vary their frequency and phase, while the general phase, the line frequency and the general power are maintained, even between two different systems as in the international electric lines; furthermore, it may vary also the phase relation between the same phases of a two-phase or a three-phase, as shown in the schemes of figures 6.
Among the advantages of the latter application, some shall be lister hereinbelow:
- short-circuit problems are eliminated;
- the correction is very quick, and corresponds to 1/2 cycle;
- the cosine may be adjusted without intervening in the excitation of the generator;
- the system shows a greater stability;
- it may adjust the transmitted power and may have a greater capacity of power transport.
Claims
1. A universal converter device with impulse sequence in the shape of a cosine wave, that transforms the electric energy of the one-phase or three-phase net into a bipolar or alternate tension in the shape of a cosine, with a variable one-phase, two-phase or three- phase frequency, from zero to the net frequency, on differentiated loads, characterized in that it makes use of phase shifters (P) and/or counters (CO) for defining the ignition moment oC .
2. A universal converter device according to claim 1 of . the three-phase P=3 kind, characterized in:
- a partial converter (CP) consisting of amplifyiers, polarity inverters, period circuits and circuits of the ignition impulse, modulators, decoders, logic circuits, load, transformers for the SCR and other;
- a generator (G) synchronized with the net frequency (Fl) that multiplies said frequency by three generating (F2) and sends impulses to a counter (CO) with three outlets (A, B and C), that reach three SCR with impulses fix in time with respect to (Fl) and therefore (EM) does not vary, while it changes when (F2) changes;
- a shifter of the system ψ S that shifts the ignition impulses in time so that the circuit varies the average outlet tension (EM) changing the phase of more or less 180° or 360°, thus determining also the polarity of the circuit.
3. A universal converter device according to claims 1 and 2, characterized in that the generator (G) is a PLL - Phase Locked Loop - or similar.
4. A universal converter device according to claim 1 characterized in that with one single net phase the generator (G) multiplies or devides (Fl), always with the same PLL or similar, so that if (F2) is smaller than (Fl), the outlets (A, B, C) of (CO) vary with respect to (Fl) and thus an average tension wave EM is produced with a wrapper of truncated sinusoid portions of the kind of a T-period cosine, while if (F2) becomes even smaller, (F3) diminishes and if (F2) becomes equal to (Fl), a wave equal to those obtained with the variants of claims 2 and 3 is obtained.
5. A universal converter device according to claims 1 and
4 characterized in that if (F2) is greater than (Fl), the same overturned cosine kind wave is obtained.
6. A universal converter device according to claims 1 and
5 characterized in that (EM) may be increased, changing the period (D) of the ingition impulse.
7. A universal converter device according to claim 1 characterized in that it allows a reduction of EM changing SS to 60°.
8. A universal converter device according to claim 1 characterized in that in an impulse sequence circuit, a shifting of the positive and negative impulses is obtained with C c , and the PLL or similar must only modify (F2) according to the kind and the number of the outlets of counter (CO).
9. A universal converter device according to claim 1 characterized in that it adjusts the power with s , D and ψcA •
10. A universal converter device according to claim 1, characterized in that it generates, beyond the cosine wave, other kinds of waves, modulating the different parameters so as to generate inclines that approach to the integral of any curve.
11. A universal converter device according to claim 1 characterized in the application, for inductive and capacitive loads, to induction motors or generators with electric lines.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/IT1994/000106 WO1996002084A1 (en) | 1994-07-08 | 1994-07-08 | A universal converter device with an impulse sequence in the shape of a cosine wave |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/IT1994/000106 WO1996002084A1 (en) | 1994-07-08 | 1994-07-08 | A universal converter device with an impulse sequence in the shape of a cosine wave |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1996002084A1 true WO1996002084A1 (en) | 1996-01-25 |
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ID=11332183
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IT1994/000106 WO1996002084A1 (en) | 1994-07-08 | 1994-07-08 | A universal converter device with an impulse sequence in the shape of a cosine wave |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO1996002084A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3585489A (en) * | 1969-06-20 | 1971-06-15 | Westinghouse Electric Corp | A low-frequency ac reference generator with inherently balanced controllable output voltage |
| US3891912A (en) * | 1972-12-25 | 1975-06-24 | Hitachi Ltd | Automatic pulse phase shifter for A.C.-D.C. or D.C.-A.C. converter |
| FR2449360A1 (en) * | 1979-02-13 | 1980-09-12 | Telemecanique Electrique | THYRISTOR THREE-PHASE MOUNTING CONTROL DEVICE |
-
1994
- 1994-07-08 WO PCT/IT1994/000106 patent/WO1996002084A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3585489A (en) * | 1969-06-20 | 1971-06-15 | Westinghouse Electric Corp | A low-frequency ac reference generator with inherently balanced controllable output voltage |
| US3891912A (en) * | 1972-12-25 | 1975-06-24 | Hitachi Ltd | Automatic pulse phase shifter for A.C.-D.C. or D.C.-A.C. converter |
| FR2449360A1 (en) * | 1979-02-13 | 1980-09-12 | Telemecanique Electrique | THYRISTOR THREE-PHASE MOUNTING CONTROL DEVICE |
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