CN1092200A - Three/one, two covert, transformers - Google Patents

Abstract

The present invention has pointed out a kind of new method, new construction of making three-phase transformer.It can be the three-phase alternating current power transformation single-phase electricity, and makes three line current symmetrical balances; Also can adopt the three-phase and four-line power supply to the single-phase or electric three-phase electricity that becomes of two-phase.It can also make the three-way transmission of electricity of three-way alternating current change the transmission of electricity of two lines into.

Description

Three/one, two covert, transformers

The present invention relates to the new construction of three-phase transformer.

Existing transformer can not make three phase transformations single-phase and make the single-phase three-phase that becomes again.

Task of the present invention is that a kind of new construction of design is made three-phase transformer.During, electricity consumption defeated, make three line current symmetrical balances, when single-phase change three-phase electricity consumption, can adopt the three-phase and four-line power supply of Y connection at single-phase realization two lines of three phase transformations.

Fig. 1 is circuit of the present invention, magnetic circuit and structure chart.On former limit, winding CZ, AX press right hand precession respectively on the left side stem stem of iron core, middle stem stem; Winding BY presses the left hand precession on the stem stem of right side.Three windings establishing former limit temporarily adopt Y connection, promptly three tail X, Y of winding, Z are tied together, and three stature A, B, C are connect three-way alternating current.Secondary, is drawn two alignments and is supplied single-phase electricity outward on middle stem stem with a winding.

If three line voltages of power supply are three axial symmetry balances, then three phase voltage U on the winding _AX, U _BY, U _CZ(be called for short U _A, U _B, U _C) also be three axial symmetry balances, so three no-load current I in the winding _AO, I _BO, I _COReach the magnetic flux Φ in three stem stems _A, Φ _B, Φ _CAll be three axial symmetry balances.Phase voltage, open-circuit excitation electric current and magnetic flux vector be (impedance of former and deputy winding is all ignored) as shown in Figure 2.

For simplifying, making the number of turn of winding CZ, BY and ED is W, and the number of turn of winding AX is 1/ $\sqrt{3}$ W。As seen from the figure,

, Φ _B=Φ _C=1/ $\sqrt{3}$ Φ _A。Because of induced potential (being voltage after ignoring the winding impedance) is directly proportional with magnetic flux, thus U _B=U _C, U _ED= $\sqrt{3}$ U _B, U _A=U _B, as seen, the single-phase side output voltage of secondary is the phase voltage of former limit three-phase side input $\sqrt{3}$ (U doubly _f= $\sqrt{3}$ U _Y）。

After secondary connects load, on secondary winding ED, will produce load current I _fSo, on winding ED, will produce a demagnetization magnetic potential, its attempt weakens its work magnetic flux Φ _AMeanwhile, on the winding of former limit,, reflection must synchronously be made: the load current I that increases its winding for guaranteeing the constant of former work magnetic flux _C1, I _B1And I _A1Because of no-load current is compared with load current, little to ignoring, so can think: I _C1≈ I _C, I _B1≈ I _B, I _A1≈ I _A

Cause

, as can be known Angle be 30 ° of electric angles.Can push away W

_B1,-W _C1With-W

_fAngle be 30 ° of electric angles, and W _A1With-W

_fAngle be that 90 ° of electric angles are (so W _A1Right

_AUnit increases magnetic action).

Cause , from current phasor Fig. 3 as can be known: I _A=I _B=I _C, they are electric currents of three axial symmetry balances.

According to Ke Shi second law: WI _f=W/ $\sqrt{3}$ I _A1Cos90 °+WI _B1Cos30 °, so I _f= $\sqrt{3}$ /2I _B1≈ $\sqrt{3}$ 2I _B。As seen, the single-phase side output current of secondary is the phase current of former limit three-phase side input $\sqrt{3}$ / 2 times of (I _f= $\sqrt{3}$ /2I _Y）。

Secondary power output: U _fI _f= $\sqrt{3}$ U _Y $\sqrt{3}$ /2I _Y=3/2U _YI _Y。On former limit, because

_B,- _CAnd _AWith-

_EDOut of phase is so voltage has only $\sqrt{3}$ / 3 can be exported (less than 1) by secondary; Because W

_B1,-W

_C1And W

_A1With-W _fOut of phase is so electric current has only $\sqrt{3}$ / 2 can be exported (less than 1) by secondary.Former limit input power is: 3 * $\sqrt{3}$ /3U _Y $\sqrt{3}$ /2I _Y=3/2U _YI _Y。The single-phase alternating current of as seen single-phase side output is to be transformed by the three-way alternating current of importing with the three-phase side of constant power.

It should be noted that: for above-mentioned reasons, the voltage, the electric current that have caused former limit to import reduce, and have made the ability drop of transformer transmitted power.The result has caused the decline to the transformer capacity utilance, and (utilance is to have caused the waste of copper cash and silicon steel sheet virtually $\sqrt{3}$ /3× $\sqrt{3}$ /2=1/2）。

The existing antikinesis of transformer.Get back to the Light Condition of this transformer earlier.If this moment, transformer was not to connect load, but connect a single phase poaer supply, the frequency of this power supply is identical with former power supply, and this power supply just in time can be to the reverse single-phase alternating current that infeeds of transformer.So secondary current I _fJust opposite with its direction when power output, so the magnetic potential that produces on winding ED is to attempt to strengthen work magnetic flux Φ _A.Meanwhile, what make synchronous reaction is: the exciting current on primary winding BY, CZ and the AX just reduces, just oppositely, tries hard to keep former work magnetic flux constant.Just illustrate that at three phase currents (being line current) single phase poaer supply is to three-way power supply input electric power oppositely the time.

Reason is the same because the out of phase of electric current, voltage, here also can push away I _f= $\sqrt{3}$ /2I _Y、U _f= $\sqrt{3}$ U _Y、。Utilance to transformer capacity also has only 1/2.The single-phase alternating current of at this moment single-phase side input has arrived the two-phase side and has become alternating current output with constant power, and transmitted power is: U _fI _f=3/2U _YI _Y

The application of this transformer in power transmission and transformation again.Three phase winding sides of this transformer are connected the three-way interchange large power supply of power supply place by Y connection, just become in single-phase winding side and single-phase alternating current,, arrive electricity consumption place, make it be Light Condition temporarily through the transmission of electricity of two lines.In electricity consumption place three phase winding sides of another this transformer are connected on by Y connection on the three-way AC power of electricity consumption place, this power supply can be an electrical network, it also can be very little three-way power supply (can adopt the single-phase electric capacity that adds to become two-phase, produce the three-way AC power of enough this no-load transformer excitations with rotating magnetic field).At this moment also become in single-phase side and single-phase alternating current, also make it be Light Condition temporarily.

The three-phase alternating current at power supply, electricity consumption two places should be consistent on frequency, voltage.When two single-phase alternating currents that are Light Condition are just in time complete close a floodgate when anti-phase and on.So above-mentioned single-phase alternating current just occurs to the situation of three-way alternating current (source) power supply.As seen this transformer is can existing phase three-wire three transformation be carried out three-way transmission of electricity and change the single-phase three-wire transformation into, carries out two lines transmissions of electricity.

Fig. 4 is three/monotropic phase, the transformer that the principle identical according to the present invention conceived another form that forms.On former limit, three windings are pressed identical rotation direction on three iron core column.Also establish it and adopt Y connection.At secondary, winding EF is identical with the rotation direction of FD, respectively the left and right side of yoke under the iron core.The tail (F) of winding EF is connect the head (F) of winding FD, outside E, D draw two alignments, supply single-phase electricity.

Reason is the same, here also can push away: I _f= $\sqrt{3}$ /2I _Y、U _f= $\sqrt{3}$ U _Y, also be to be 1/2 to the utilance of transformer capacity.With aforementioned different be that both are obtaining U _f= $\sqrt{3}$ U _YMethod on different.The former subtracts each other by vector flux to obtain $\sqrt{3}$ Doubly former magnetic flux, and obtain $\sqrt{3}$ Times primary voltage value; The latter subtracts each other by vector voltage to obtain $\sqrt{3}$ Times primary voltage value.As seen the former is many with iron, and the latter is many with copper, and is identical on electric current, voltage and power.

The transformer of this version of Fig. 4, in wiring, change slightly and just can form three/two covert, transformers.As shown in Figure 5, change is as follows: 1, winding AX reversal connection; 2, the tail (D) of winding ED is connect the tail (D) (compare with Fig. 4, be equivalent to FD and connect conversely) of winding FD.At this moment but three-phase side adopts also △ of Y() the shape connection, two-phase side V-connection all is connected to three-phase alternating current.

Now analyze the two-phase side and make the situation that secondary is made on former limit, three-phase side.Because U _ED, U _DF120 ° of electric angles of equal and opposite in direction mutual deviation, from voltage to the exciting current again to magnetic flux, _B,

_CAlso 120 ° of electric angles of equal and opposite in direction mutual deviation.Cause

,

_B,

_CWith _AThe equal and opposite in direction angle is 60 ° of electric angles, so

Also equal and opposite in direction presss from both sides 60 ° of electric angles.Cause

Just become the voltage of the symmetrical balance of equal and opposite in direction mutual deviation 120 ° of electric angles.The former and deputy limit of magnitude of voltage is equal, i.e. U _Y=U _V

Secondary connects that its three line currents also are symmetrical balances after the load of balance.Three load currents are degaussings.For making former work magnetic flux constant, just synchronously increase load current on the winding of former limit.

Cause _B,

_CWith

_APress from both sides 60 ° of electric angles, so W

_B, W

_CWith W

_AAlso press from both sides 60 ° of electric angles, so W

_AIt also is degaussing.According to Ke Shi second law:

, get I _E1=3/2I _BWhen disregarding the winding impedance: I _B=2/3I _EBe that secondary three-phase side output current is 2/3 times of former limit two-phase side input current, i.e. I _Y=2/3I _V

Secondary power output: 3U _YI _Y=3U _V2/3I _V=2U _VI _VAs seen secondary can the power (capacity) of former limit input all output go, that is to say, be 1 to the utilance of transformer capacity.

By analyzing as can be known, this three-phase/two phase transformer are compared with the three-phase/three-phase transformer of equal capacity, because dwindling and the shortening of winding average perimeter of core window, can have province's copper, economize iron and advantage such as energy-conservation.

Visible in sum the present invention has following advantage:

One, can become single-phase alternating current to three-way alternating current, and make three-way power supply load balance.

Two, can become three-phase alternating current to single-phase alternating current, and can adopt three-phase four-wire power supply.

Three, can change the three-way transmission of electricity of three-way alternating current the transmission of electricity of into two lines.

Four, two-phase/three-phase transformer is not only economized copper, is economized iron and energy-conservation but also can adopt three-phase four-wire power supply.Make it under the situation of existing three-way transmission of electricity, also can promote, use.

Claims (2)

1, use three phase windings on one side, otherwise another side, so this transformer can become three-phase electricity single-phase or two-phase is electric also can with single-phase or two phase windings.Feature is:

A. three phase windings adopt Y or Δ shape connection to connect three-way alternating current.

B. single-phase winding order cross streams electricity, two phase windings adopt V-connection to connect three-way alternating current.

C. when single-phase change three-phase electricity, add the three phase excitation source in three-phase side.

2, according to claim 1, not only can make three/monotropic phase, transformer, also can be used for the two lines transmission of electricity of three-way alternating current.

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