CN101087102A - Three-phase front feedback serial and parallel compensation high-power factory rectifier - Google Patents

Abstract

A kind of feedforward parallel compensated three-phase high power factor rectifier includes three-phase main commutating circuit and assisted feedforward compensated circuit, three-phase main commutating circuit is common capacitance filter bridge-type rectifier, input of feedforward compensated circuit is parallel with input of main commutating circuit, it includes low phase rectifier, single BOOST boosting converter and separating converter, the output of the BOOST boosting converter is parallel with output of the main commutating circuit, the output of the separating converter is concatenated with output of the main commutating circuit. The separating converter which is concatenated with output of the main commutating circuit compensates voltage wave output by the main commutating circuit and provides definite direct voltage to realize adjustment of direct output voltage, current absorbed by the feedforward compensated circuit from three phase power fills defect of normal rectifier, improves current wave, decreases distortion of harmonization, increases power efficiency.

Description

Three-phase front feedback serial and parallel compensation high-power factory rectifier

Technical field

The present invention relates to three-phase rectifier, especially a kind of front feedback serial and parallel compensation three-phase high power factor rectifier.

Technical background

Chinese patent CN200420108964.X discloses a kind of large power variable frequency induction smelting device of 24 pulse wave rectifiers, this device uses two rectifier transformers, on its four groups of secondary each and connect two cover semiconductor power rectification circuits, the output of quadruplet semiconductor power rectification circuit is connected in series big reactor filtering respectively, use silicon-controlled voltage regulation, the circuit complexity, the cost height, and contain still that to account for fundamental current be 4.4%, 4.0% 23 times, 25 subharmonic currents, the total current aberration rate still is 5.9%, and electrical network is caused harmonic wave harm.

Chinese patent CN01140014.5 discloses a kind of three-phase power supply parallel feedforward compensation power factor correction circuit, and this circuit is auxiliary feed forward type compensating circuit in parallel on the main rectification circuit of normal three phase mains.This feed forward type compensating circuit divides 12 beat work in a complete cycle, the big phase of absolute value of voltage in the two-phase electricity that compensating circuit makes bidirectional switch turn-off respectively to be in same polarity by control circuit between the phase region of correspondence in order, the bridge rectifier output direct current that communicated with heteropolarity that absolute value is little, through booster converter Control current waveform, boosting is injected into the output of former three-phase bridge rectification circuit again.This circuit make two same polarities mutually in the absolute value of voltage low electric current that suitable waveform has been arranged mutually, reduced the electric current of the high phase of absolute value of voltage simultaneously, also improved the current waveform of heteropolarity phase, institute is so that harmonic distortion obviously reduces, circuit working efficient is very high.But this circuit does not change the output voltage wave mode of rectifier, and promptly output dc voltage still has ripple, and when output inserted big filter capacitor, it is big that the distortion factor becomes rapidly, for the especially resistive load of the linear load of industrial a large amount of existence, and can't voltage stabilizing.

Summary of the invention

The objective of the invention is provides a kind of three-phase front feedback serial and parallel compensation high-power factory rectifier on Chinese patent CN01140014.5 patent basis, make it can not only reduce the harmonic component of power supply, change the output voltage wave mode of rectifier simultaneously, promptly eliminate the output dc voltage ripple, when output inserts big filter capacitor, the distortion factor does not increase, and can provide the galvanic current pressure in certain scope, adapts to the demand of various loads.

The solution that the present invention adopts is: 1) increase an isolated converter in Chinese patent CN01140014.5 auxiliary compensating circuit in parallel, the secondary commutation output of this isolated converter is connected with main converter output, not only fill up the voltage ripple of main converter output, and certain limit voltage stabilizing adjustment is provided; 2), make the converter can be at each at the two ends of the BOOST of former booster converter diode paralleling switch pipe

Phase region between initial or end can provide very little and output to low alternate rectification output reverse current from main rectification.

City's electrical network is a three-phase constant voltage alternating current, and the transient power equilibrium principle is the important principles and the excellent specific property of three-phase electricity.The DC power supply of actual needs mostly is the constant voltage power supply greatly, the variation of load is the firm power load for three-phase electricity during much smaller than power frequency, and the motor load of three phase electric machine frequency conversion speed-adjusting system is symmetrical, the variation of load also is the firm power load for three-phase electricity during much smaller than power frequency.Design good transducer and should be able to realize electric energy galvanic stable circulation and do not need energy storage filtering from the three-phase alternating current to the constant voltage, also just can not be to the electrical network radiate harmonic.Traditional diode, silicon controlled rectifier and linear voltage stabilization rectifier are undesirable by jumbo inductance and the electric capacity direct current that ripple energy filtering obtains of handling up, and produce the harmonic wave to the electrical network radiation, increase cost and work the mischief.

What the circuit that the present invention uses was identical with Chinese patent CN01140014.5 is that main rectification circuit I comprises main three-phase bridge 110 and main filter capacitor 120; Feed forward type compensating circuit II comprises low alternate rectifier 20, booster converter 21, but paralleling switch pipe 210, switching tube 211 are distinguished in the two ends of the BOOST diode 212 of booster converter 21, diode 213; Key is to increase the isolated converter 22 that output is connected with aforementioned patent output.Adjust isolated converter 22 and make its output voltage have the ripple of exporting opposite sign but equal magnitude with main converter, so that total output voltage is constant.For stable load, rectifier can provide stable electric current, because output can insert big electric capacity and not produce harmonic wave, this rectifier also has excellent adaptability to the unsteady load that needs burning voltage simultaneously.

The cycle of three-phase electricity is 2 π in following statement, and A, B, C represent three-phase respectively, differ into The starting point of A phase is zero, and the peak value of line voltage is 1, and the power output of rectifier is 1, then V _oI _o=1, disregard the loss of rectifier self in the calculating, three-phase input voltage is respectively:

$V_a=\mathrm{Sin}\left(\mathrm{\ωt}\right)/\sqrt{3}$ $V_b=\mathrm{Sin}(\mathrm{\ωt}+2\mathrm{\π}/3)/\sqrt{3}$ $V_c=\mathrm{Sin}(\mathrm{\ωt}+4\mathrm{\π}/3)/\sqrt{3}$

Power factor is that 1 o'clock three-phase current should be respectively:

I _a＝Sin(ωt)/Sin(π/3) I _b＝Sin(ωt+2π/3)/Sin(π/3) I _c＝Sin(ωt+4π/3)/Sin(π/3)

Control circuit detects three-phase input voltage and determines phase place and input voltage peak value, and the control mode of low alternate rectification is identical with Chinese patent CN01140014.5.Any time that three-phase electricity zero-crossing point is outer, it is same polarity that two-phase is always arranged, and remaining phase polarity is opposite, and the same polarity two crosspoint external voltage that is divided by is one high and one low, in normal rectification circuit, and the low phase of voltage in the same polarity two-phase, before and after promptly every phase zero crossing

The interval is blocked and produces electric current disappearance.The feed forward type compensating circuit II auxiliary in parallel of Chinese patent CN01140014.5 has turn-offed the high phase of voltage in the same polarity two-phase, has not only compensated Electric current disappearance between phase region, and improved should be in the period current waveform of same polarity phase with it, consequently do not change the output voltage and the electric current wave mode of rectifier, just make the middle mutually low electric current that suitable waveform has been arranged mutually of absolute value of voltage of two same polarities, reduced the electric current of the phase that the same polarity absolute value of voltage is high with it simultaneously, also improved the current waveform of heteropolarity phase, make harmonic distortion obviously reduce, circuit working efficient is very high, but the ripple of the voltage and current of its output still is retained, and still needs filtering for passive load.

The present invention increases the isolated converter 22 of connecting with output.Control principle of the present invention is:

1. corresponding to each

～0 or 0～

The interval, according to output voltage V _oAdjust isolated converter 22, make its output current $I_0=\frac{1}{V_0};$

2. corresponding to each

～0 or 0～

The interval, the output current that the electric current of control booster converter 21 makes low alternate rectifier is for sinusoidal wave ～0 or 0～

Part.

It all is corresponding sinusoidal wave part that the characteristic of three-phase electricity like this will make three-phase input current, has just accomplished constant voltage output, the unity power factor input.

Because above-mentioned solution has increased the isolated converter that can compensate output voltage ripple in feed forward type compensating circuit II, make rectifier can accomplish not have the radiation of humorous wave direction input, ripple-free output.Whole process does not have the energy storage component relevant with its harmonic wave with fundamental frequency, and cost is low, is particularly advantageous in the stable operation of common frequency power network.

The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments:

Description of drawings

Fig. 1 is a schematic block circuit diagram of the present invention;

Fig. 2 is the three-phase mains voltage waveform;

Fig. 3 is the voltage current waveform of common three-phase bridge rectification output voltage and this patent output;

Fig. 4 is one 0 current-voltage waveform to interval each branch road in π/6;

Fig. 5 is one 0 power circuit to interval each branch road in π/6.

Embodiment

In schematic block circuit diagram shown in Figure 1, circuit is made up of main rectification circuit I and feed forward type compensating circuit II, and feed forward type compensating circuit II is by low alternate rectifier 20, and booster converter 21 and isolated converter 22 are formed.The input of the input of main rectification circuit I and feed forward type compensating circuit II is in parallel, the output of the booster converter 21 of feed forward type compensating circuit II and the output-parallel of main rectification circuit I, the output of the isolated converter 22 of feed forward type compensating circuit II and the output of main rectification circuit I series connection.Main rectification circuit I comprises three-phase bridge 110 and filter capacitor 120, three-phase electricity input 100 links to each other with three-phase bridge 110 inputs among the main rectification circuit I, the output of three-phase bridge 110 links to each other with filter capacitor 120, the low alternate rectifier 20 of feed forward type compensating circuit II is by 6 GT0 (201,202,203,204,205,206) three-phase bridge of Gou Chenging and filter capacitor 207 are formed, and its operation principle is identical with Chinese patent CN01140014.5; Booster converter 21 is by boost inductance 215, boost inductance 216, boosted switch pipe 214, boost diode 212, diode 213 are formed, there are switching tube 210, switching tube 211 in the two ends that are boost diode 212, diode 213 with the difference of Chinese patent CN01140014.5 parallel connected in reverse phase respectively: isolated converter 22 is by switching tube 220, transformer 221, rectifier diode 222, fly-wheel diode 223, filter inductance 224 and electric capacity 225 are formed.

Fig. 2 is the three-phase rectifier mains voltage waveform, and by voltage waveform behind the main rectifier bridge 110 such as the Vm among Fig. 3, each cycle is contained 6 pulse waves, and amplitude is 0.134.The purpose that adds isolated converter 22 is exactly in order to eliminate this ripple.

Below get 0～

Be example between phase region, the control method of this patent and the current-voltage waveform of each branch road are done detailed statement.

As depicted in figs. 1 and 2, arrive between π/6 phase regions 0, the output voltage of main three-phase bridge 110 is Vm, and electric current is provided with B mutually mutually by C.In low alternate rectifier 20, B is turned off mutually, and low alternate rectifier 20 output voltages are Voa, and electric current is provided with C mutually by A, for being that the booster converter 21 of Vm parallel connection, the isolated converter 22 of connecting are powered with the output voltage of main three-phase bridge 110.That is to say at this interval A and have only electric current to pass through low alternate rectifier 20 mutually, B has only electric current to pass through main rectification circuit I mutually, and C has electric current to pass through low alternate rectifier 20 and main rectification circuit I mutually.

For guaranteeing output stable DC voltage Vo, the output of the isolated converter 22 of series connection:

V _oa＝v _o-v _m＝v _o-Sin(ωt+π/2)＝V _ad+(1-Sin(ωt+π/2))

Promptly on the basis of the main three-phase bridge 110 output voltage V m ripples of compensation, provide certain pure direct voltage Vad to satisfy the demand of voltage-regulation.As isolated converter 22 is single-end ortho-exciting pattern shown in Figure 1, and the selection principle that its transformer 223 primary and secondary no-load voltage ratios are n is:

As Vad=0, n=3.28 then should be smaller for keeping surplus n.

By aforementioned control principle 1, the forward conduction average current of isolated converter 22 and switching tube 220 should be Io/n, and the complete period, average current Ias should be:

$I_{\mathrm{as}}=\frac{1-I_o\mathrm{Cos\ωt}}{\mathrm{Sin}(\mathrm{\ωt}+\mathrm{\π}/6)}$

Ias among its change curve such as Fig. 4.

Because the output of main three-phase bridge 110 is connected with isolated converter 22, the output current of control isolated converter 22 is definite value Io, also making the winner's three-phase bridge 110 and the output current sum of booster converter 21 is Io, and the internal resistance of three-phase electricity is fully little, Vm and Voa can regard voltage source as, but the electric current that the output current of adjusting booster converter 21 like this not only can standard master three-phase bridge 110 but also the output current of the low alternate rectifier 20 of standard.

By the output current of control principle 2 adjustment booster converters 21, even the output current Iap of low alternate rectifier 20 is the positive string section between 0～π/6 phase regions.

$I_{\mathrm{ps}}=\frac{\mathrm{Sin\ωt}}{\mathrm{Sin}(\mathrm{\π}/3)}$

Be the electric current of A phase.

The output current Iam of booster converter 21 should be:

$I_{\mathrm{am}}=(\frac{\mathrm{Sin\ωt}}{\mathrm{Sin}(\mathrm{\π}/3)}-\frac{1-I_o\mathrm{Cos\ωt}}{\mathrm{Sin}(\mathrm{\ωt}+\mathrm{\π}/6)})\frac{\mathrm{Sin}(\mathrm{\ωt}+\mathrm{\π}/6)}{\mathrm{Cos\ωt}}$

And the electric current of B phase is the electric current by main rectification circuit I:

$I_b=I_m=I_o-I_{\mathrm{am}}=I_o-(\frac{\mathrm{Sin\ωt}}{\mathrm{Sin}(\mathrm{\π}/3)}-\frac{1-I_o\mathrm{Cos\ωt}}{\mathrm{Sin}(\mathrm{\ωt}+\mathrm{\π}/6)})\frac{\mathrm{Sin}(\mathrm{\ωt}+\mathrm{\π}/6)}{\mathrm{Cos\ωt}}=\frac{\mathrm{Sin}(\mathrm{\ωt}+2\mathrm{\π}/3)}{\mathrm{Sin}(\mathrm{\π}/3)}$

The electric current of C phase:

$I_c=I_a+I_b=\frac{\mathrm{Sin}(\mathrm{\ωt}+\mathrm{\π}/3)}{\mathrm{Sin}(\mathrm{\π}/3)}$

0 arrives

The electric current of each several part and each branch road is shown among Fig. 4 between phase region.The power P m of main rectification circuit I, booster converter 21 is to the power P p of main rectification circuit I transmission, and the variation of the power P s of isolated converter 22 is shown among Fig. 5.

It is alternate that above analysis is adapted in 2 π complete periods 6

Between phase region, all the other 6

Symmetrical with it between phase region.

So use circuit of the present invention, just obtained constant voltage and current output, the input of perfect sine wave electric current by aforesaid control principle, and do not related to any energy access relevant with power frequency and harmonic wave thereof.Rectifier for three-phase electricity power supply constant power load is supposed to be.

Certainly; the present invention's three-phase electricity connection in series-parallel feedforward compensation formula high-power factory rectifier is not limited to illustrated embodiment; as the low alternate rectification circuit 20 that constitutes of the power circuit that adopts other form, booster converter 21, isolated converter 22 etc., these variations all drop within protection scope of the present invention.

Claims (5)

1, a kind of three-phase connection in series-parallel feedforward compensation formula high-power factory rectifier, comprise three-phase master rectification circuit and auxiliary compensating circuit, it is characterized in that: three-phase master rectification circuit is common capacitor filtering bridge rectifier, the input parallel connection of the input of feed forward type compensating circuit and this main rectification circuit, it contains low alternate rectifier, single BOOST booster converter and isolated converter, the output of this BOOST booster converter and the output-parallel of this main rectification circuit, the output of this isolated converter is connected with the output of this main rectification circuit.

2, three-phase connection in series-parallel feedforward compensation formula high-power factory rectifier according to claim 1, it is characterized in that: three-phase electricity links to each other with three-phase bridge input in the main rectification circuit (I), the output of three-phase bridge links to each other with filter capacitor, the input of the low alternate rectifier in the feed forward type compensating circuit (II) links to each other with three-phase electricity, the output of low alternate rectifier, the input of booster converter and the input of isolated converter link to each other, the output of the output of booster converter and main rectification circuit (I) is connected in parallel, and the output of the output of isolated converter and main rectification circuit (I) is connected in series.

3, three-phase connection in series-parallel feedforward compensation formula high-power factory rectifier according to claim 1 and 2, it is characterized in that: the isolated converter (I) that the output in its auxiliary compensating circuit is connected with the output of main rectification circuit just can compensate the voltage ripple of the output of main rectification circuit, realizes direct current output.

4, three-phase connection in series-parallel feedforward compensation formula high-power factory rectifier according to claim 1 and 2, it is characterized in that: outside the voltage ripple of the output of the main rectification circuit of isolated converter (I) that the output in its auxiliary compensating circuit is connected with the output of main rectification circuit compensation, provide certain direct voltage to realize the adjusting of VD.

5, three-phase connection in series-parallel feedforward compensation formula high-power factory rectifier according to claim 1 and 2, it is characterized in that: the output in its auxiliary compensating circuit has compensated the electric current that is blocked the three-phase electricity mutually with the isolated converter that the BOOST booster converter of the output-parallel of this main rectification circuit and output are connected with the output of main rectification circuit from the electric current sum that this low alternate rectifier obtains, and has also proofreaied and correct the current waveform of all the other two-phases.

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