CN101783601B - Multiphase current type PWM rectifier based on dual controllable rectifier bridge of hybrid switch - Google Patents

Abstract

The invention discloses a multiphase current type PWM rectifier based on the dual controllable rectifier bridge of a hybrid switch, which is composed of five modules, wherein the module 1 is composed of an LC filter, the modules 2 and 4 are respectively a thyristor rectifier bridge, the module 3 can be two reverse-conducting full-control electronic switches which are independently controlled, and the module 5 is an LC filter with a freewheel diode. The rectifier with the structure is mainly characterized in that two groups of thyristor rectifier bridges are adopted so as to provide enough time for the thyristor to conduct and restore to the forward blocking state; and requirements on thyristor cut-off speed by the rectifier bridge can be lowered. Thus, the invention can lower limitation on the working frequency of the rectifier circuit by the cut-off time of the thyristor of a bridge arm in the rectifier bridge, inhibits network side harmonic wave, and reduces the cost of the switching element of the rectifier without increasing the cost of filtering elements.

Description

A kind of multiphase current type PWM rectifier of the two controlled rectification bridges based on hybrid switch

Technical field

The present invention relates to the multiphase current type PWM rectifier, especially, belong to electric and electronic power converter technique field based on the multiphase current type PWM rectifier of two controlled rectification bridges of hybrid switch.

Background technology

At present to the harmonic content of grid side conditional in high-power Three-Phase PWM Rectifier adopt three-phase PWM voltage-type rectifier or three-phase PWM current mode rectifier mostly.

Three-phase PWM voltage-type rectifier is the booster type circuit; Requiring supply power voltage to be lower than under the load request of grid line voltage peak; Need series connection second level DC transfer circuit to come step-down, this has not only increased the volume and the cost of total system, and has reduced the efficient of circuit.Three-phase PWM current mode rectifier is the voltage-dropping type rectifier, and the DC side output voltage is lower than the grid line voltage peak; But need the series connection of IGBT and fast recovery diode to use in the rectifier bridge,, need diode to bear back-pressure,, reduce the efficient of circuit so the conducting loop has increased the conduction loss of two diodes because the reverse blocking capability of IGBT is poor; The IGBT of brachium pontis needs No. one accessory power supply to drive under each in addition, adds the driving power of the IGBT of brachium pontis, needs 4 road driving powers altogether; Powerful in addition IGBT price is higher than the thyristor of same current voltage tolerance.

Development is afterwards sent as an envoy to and is replaced the PWM current mode rectifier (application (patent) number: 200720109908.1) of the three-phase hybrid switch of IGBT rectifier bridge with thyristor rectifier bridge; Re-using an IGBT connects with thyristor rectifier bridge; Directly break off the conducting electric current of IGCT in the rectifier bridge, offer the ability of thyristor rectifier bridge pulsewidth modulation like this; Use IGCT can save fast recovery diode in addition, improved the efficient of circuit; IGCT can drive with pulse transformer in addition, so only need No. one accessory power supply to drive, adds the IGBT driving power, only needs 2 road driving powers altogether, thereby has simplified the drive circuit of circuit.

Yet though use hybrid switch can reduce the cost of the switching device of circuit, the long turn-off time of thyristor has been limited the operating frequency of circuit.Therefore, for the ripple that suppresses the current on line side harmonic wave and reduce the DC side electric current, so the volume and the cost of inductance and electric capacity in the needs increasing filter are the global advantage of sort circuit and not obvious.

Summary of the invention

In view of above-mentioned; The multiphase current type PWM rectifier that the purpose of this invention is to provide a kind of two controlled rectification bridges based on hybrid switch; To reach turn-off time of reducing the thyristor of brachium pontis in the rectifier bridge operating frequency restriction to rectifier circuit; Reduce the cost of the switching device of rectifying installation when suppressing side harmonics, and do not increase the cost of filtering device.And can realize net side power factor near 1, Adjustable Output Voltage.

Basic ideas of the present invention are, utilize the wheel of twin crystal brake tube bridge to change jobs, and make the thyristor that needs commutation have the above turn-off time of switch periods at least half, thereby greatly promote the switch operating frequency of thyristor circuit.

The multiphase current type PWM rectifier of the two controlled rectification bridges based on hybrid switch of the present invention; Number of phases M >=2; Be made up of five modules, wherein module 1 is made up of M group LC filter, and module 2 is respectively thyristor M commutating phase bridge with module 4; Module 3 is that two independent controls contrary led type and controlled electronic switch entirely, and module 5 is the LC filter of band fly-wheel diode;

The M that the input of module 1 is connected respectively to electrical network is each phase inlet wire mutually, each brachium pontis mid point mutually that the output of module 1 is connected respectively to module 2 and module 4, and the M of module 1 filter capacitor end connects into mid point O;

First of the link block 3 contrary type of leading is controlled second of link block 3 between electronic switch, module 2 negative output terminals and module 4 negative output terminals entirely and is contraryly led type and control electronic switch entirely between module 2 positive output ends and module 4 positive output ends, and the first contrary type of leading of link block 2 positive output ends is controlled second of electronic switch and link block 2 negative output terminals entirely to control the polarity of electronic switch entirely against the type of leading opposite;

Module 5 positive input terminal connection modules 4 positive output ends, module 5 negative input end connection modules 4 negative output terminals, the output of the input of module 1 and module 5 is respectively the input and the output of rectifier of the present invention.

Among the present invention, the M group LC filter of forming module 1 can be a second order LC filter, or the 2n rank LC filter of n level series connection, n >=2.

Among the present invention, the LC filter of module 5 band fly-wheel diodes can be second order LC filter, or the 2k rank LC filter of k level series connection, k >=2.

Above-mentioned first contraryly leads that type is controlled electronic switch entirely and the second contrary type of leading is controlled electronic switch entirely and can be adopted IGBT or IGCT or the IECT that contains the reverse parallel connection diode.

The present invention compared with prior art has following advantage:

1, raising hybrid switch circuit is distributed to thyristor and is returned to the time of forward blocking state by conducting, thereby has reduced the requirement to the thyristor turn-off speed, and triode thyristor also may be used in this rectification circuit topology.In the multiphase current type PWM rectifier of the two controlled rectification bridges based on hybrid switch of the present invention as use high speed thyristor, its operating frequency can rise to about 8kHz from about the 2kHz of conventional hybrid switch circuit, even higher.And under the situation that improves operating frequency, still can realize netting the side power factor near 1, Adjustable Output Voltage.

2, compare with complete controlled PWM current mode rectifier based on the double rectifier bridge circuit of hybrid switch; Also can be operated under the sufficiently high frequency, under the promptly identical filtering components and parts condition, not only reduce the cost of switching tube; And reduced conduction loss, improve the efficient of circuit; Drive circuit also obtains simplifying in addition.

Description of drawings

Fig. 1 is based on the circuit theory diagrams of multiphase current type PWM rectifier of two controlled rectification bridges of hybrid switch.

Fig. 2 is a 2n rank LC filter schematic diagram of forming the M group n level series connection of module 1, n >=2.

Fig. 3 is a 2k rank LC filter schematic diagram of forming the k level series connection of module 5, k >=2.

Fig. 4 is the polarity definition of full-control type electronic switch.

Fig. 5 is based on the circuit theory diagrams of three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch.

Fig. 6 is the space current polar plot of three-phase electricity flow pattern PWM rectifier.

Fig. 7 is based on the sequence chart of vector long vector, short vector and zero vector in the cycle of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch;

The switching tube figure that Fig. 8 opens based on long vector in the electrical network power frequency period of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch and short vector correspondence.

Fig. 9 is based on the PWM mode oscillogram of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch.

Figure 10 is based on the oscillogram of the pattern one of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch.

Figure 11 is based on the oscillogram of the pattern two of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch.

Figure 12 is based on the oscillogram of the pattern three of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch.

Figure 13 is based on the equivalent circuit diagram of the pattern one of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch:

(a) sector I interval [0, π/6) short-and-medium vector of vector cycle makes the simple equivalent circuit figure of time spent;

(b) sector I interval [0, π/6) vector in the cycle long vector make the simple equivalent circuit figure of time spent;

(c) sector I interval [0, π/6) vector in the cycle zero vector make the simple equivalent circuit figure of time spent.

Figure 14 is based on the equivalent circuit diagram of the pattern two of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch:

(a) sector I interval [π/6, π/3) first short-and-medium vector of vector cycle makes the simple equivalent circuit figure of time spent;

(b) sector I interval [π/6, π/3) first vector in the cycle long vector make the simple equivalent circuit figure of time spent;

(c) sector I interval [π/6, π/3) first vector in the cycle zero vector make the simple equivalent circuit figure of time spent.

Figure 15 is based on the equivalent circuit diagram of the pattern three of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch:

(a) II first short-and-medium vector of vector cycle in sector is made the simple equivalent circuit figure of time spent;

(b) first vector of sector II in the cycle long vector make the simple equivalent circuit figure of time spent;

(c) first vector of sector II in the cycle zero vector make the simple equivalent circuit figure of time spent.

Figure 16 is based on the theory diagram of control system of three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch.

Figure 17 is based on A phase voltage, electric capacity phase voltage and the phase current simulation waveform figure of three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch.

Embodiment

Referring to Fig. 1; The multiphase current type PWM rectifier of the two controlled rectification bridges based on hybrid switch of the present invention; Form by five modules; Wherein module 1 is made up of M group LC filter, and module 2 is respectively thyristor M commutating phase bridge with module 4, module 3 be two independent controls control electronic switch T entirely against leading type ₁, T ₂, module 5 is the LC filter of band fly-wheel diode;

The input md1_in1 of module 1, md1_in2 ..., md1_inM M each phase inlet wire mutually of being connected respectively to electrical network; The output md1_out1 of module 1, md1_out2 ..., md1_out_M be connected respectively to module 2 and module 4 each mutually brachium pontis mid point md2_in1, md2_in2 ..., md2_inM and md4_in1, md4_in2 ..., md4_inM, the M of module 1 filter capacitor end connects into mid point O;

Module 2 positive output end P ₁With module 4 positive output end P ₂Between first contrary lead type and control electronic switch T entirely of link block 3 ₁, module 2 negative output terminal N ₁With module 4 negative output terminal N ₂Between second contrary lead type and control electronic switch T entirely of link block 3 ₂, link block 2 positive output end P ₁First contrary lead type and control electronic switch T entirely ₁With link block 2 negative output terminal N ₁Second contrary lead type and control electronic switch T entirely ₂Polarity opposite.First, second controls electronic switch entirely against the type of leading can adopt IGBT or IGCT or the IECT that contains the reverse parallel connection diode, and the reverse parallel connection diode plays the contrary effect of leading;

Module 5 positive input terminal P ' connection modules 4 positive output end P ₂, module 5 negative input end N ' connection modules 4 negative output terminal N ₂, the output of the input of module 1 and module 5 is respectively the input and the output of rectifier of the present invention.P among the figure ^*And N ^*Be respectively the positive and negative output of module 5.

Among the present invention, the M group LC filter of forming module 1 can be a second order LC filter, also can be the 2n rank LC filter that n level as shown in Figure 2 is connected, n>=2, inductance L _S1And capacitor C _S1The filter of forming connects inductance L at the back _S2And capacitor C _S2The filter of forming is at last by inductance L _SnAnd capacitor C _SnThe filter of forming is as the output of module 1.

Among the present invention, the LC filter of module 5 band fly-wheel diodes can be second order LC filter, also can be the 2k rank LC filter that k level as shown in Figure 3 is connected, k>=2, inductance L _D1, L _D1' and capacitor C _D1The filter of forming connects inductance L at the back _D2, L _D2' and capacitor C _D2The filter of forming is at last by inductance L _Dk, L _Dk' and capacitor C _DkThe filter of forming is as the output of module 5, as long as wherein satisfy inductance L _Dk, L _Dk' the series connection equivalent inductance can filtering the effect of high-frequency harmonic get final product inductance L _Dk, L _Dk' in any one can be short circuit or inductance L _Dk, L _Dk' be to use two inductance of same core.When the load request rectification circuit was output as current source, the filter in the module 5 can be a big dc inductance L _dGet final product, do not need dc capacitor C _d, perhaps dc capacitor C _dIt is the filter capacitor of low capacity; If the load request rectification circuit is output as voltage source, the filter capacitor C in the module 5 then _dIt should be jumbo storage capacitor; When using multistage DC filter to filter capacitor C _DkSame requirement is also arranged.

First, second controls electronic switch T entirely against leading type ₁And T ₂Polarity be defined as: when device bore forward voltage, the terminal that electronic switch connects positive voltage was an anode, and the terminal that connects negative voltage is negative terminal, and is as shown in Figure 4.T ₁And T ₂Anode be anode, negative terminal is a negative electrode, its forward conduction (being that electric current flows to negative electrode from anode) controlled terminal control is oppositely conducted electricity uncontrolled.

Based on the multiphase current type PWM rectifier of two controlled rectification bridges of hybrid switch, normal conditions are three-phase circuits, i.e. M=3.

The circuit theory diagrams of the three-phase electricity flow pattern PWM rectifier of the two controlled rectification bridges that are based on hybrid switch shown in Figure 5.This rectifier is made up of five modules, and wherein module 1 is made up of 3 groups of LC filters, and module 2 is respectively the thyristor three-phase commutation bridge with module 4, and two thyristor rectifier bridges are by thyristor S ₁₁～S ₆₁And S ₁₂～S ₆₂Form, module 3 is that two independent controls contrary led type and controlled electronic switch T entirely ₁, T ₂, module 5 is the LC filter of band fly-wheel diode;

The input A of module 1, B, C connect the e with the grid alternating current source respectively _a, e _bAnd e _cConnect the output terminals A of module 1 _Md1, B _Md1, C _Md1Each that is connected respectively to module 2 and module 4 be brachium pontis mid point A mutually _Md2, B _Md2, C _Md2And A _Md4, B _Md4, C _Md4, 3 filter capacitor ends of module 1 connect into mid point O;

Module 2 positive output end P ₁First of link block 3 contrary led type and is controlled electronic switch T entirely ₁Anode, module 4 positive output end P ₂First of link block 3 contrary led type and is controlled electronic switch T entirely ₁Negative terminal, module 2 negative output terminal N ₁Second of link block 3 contrary led type and is controlled electronic switch T entirely ₂Negative terminal, module 4 negative output terminal N ₂Second of link block 3 contrary led type and is controlled electronic switch T entirely ₂Anode; First contrary lead type and controls electronic switch T entirely ₁Control electronic switch T with second entirely against leading type ₂Be IGBT or IGCT or the IECT that contains the reverse parallel connection diode;

Module 5 positive input terminal P ' connection modules 4 positive output end P ₂, module 5 negative input end N ' connection modules 4 negative output terminal N ₂, P among the figure ^*And N ^*Be respectively the positive and negative output of module 5, be connected to load.

Further specify the pulse width modulation controlled mode of this rectifier below.

Current mode PWM rectifier of the present invention uses the current mode space vector method of modulation double rectifier bridge to realize the unsteady flow function.

The basic principle of current mode space vector method is: in the vector cycle of initialization circuit, each vector will calculate interior two effective vectors of this vector cycle and action time thereof before the cycle.Effectively vector is meant through opening in the rectifier bridge out of phase one and goes up brachium pontis and a following brachium pontis and be communicated with certain two powering load mutually in the electrical network; Vector is meant the time that upper and lower bridge arm is opened action time; Zero vector is meant does not have the electrical network powering load.

The space vector method of in three-phase system, using one has seven basic current space vectors, and is as shown in Figure 6, and wherein six effective vectors are respectively I ₁(S ₁S ₆), I ₂(S ₁S ₂), I ₃(S ₃S ₂), I ₄(S ₃S ₄), I ₅(S ₅S ₄), I ₆(S ₅S ₆), and a zero vector I ₀I among the figure ^*Be reference vector; θ is the phase angle of current sector.In the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges based on hybrid switch as shown in Figure 6, S ₁Expression conducting thyristor S ₁₁Or S ₁₂S ₂Expression conducting thyristor S ₂₁Or S ₂₂S ₃Expression conducting thyristor S ₃₁Or S ₃₂S ₄Expression conducting thyristor S ₄₁Or S ₄₂S ₅Expression conducting thyristor S ₅₁Or S ₅₂S ₆Expression conducting thyristor S ₆₁Or S ₆₂

Convenient, as shown in Figure 7 for the statement of space vector control method that the present invention is used, done to give a definition: in the vector cycle T _sIn two effective vectors and a zero vector effect are arranged; Make the net side be called long vector I in cycle at same vector through the bigger vector of voltage of rectifier bridge output _Long, vector action time is T _LongMake the net side be called short vector I through the less vector of rectifier bridge output voltage _Short, vector action time is T _ShortThe vector of the obstructed over commutation output voltage of net side is zero vector I ₀, vector action time is T ₀Shown in Figure 8, be that a sector is divided into 6 sectors with a power frequency period [0,2 π] with π/3, specify two effective vectors in each sector; As specifying effective vector I in the I of sector ₁And I ₆Interval in a sector [0, π/6) with interval [π/6, π/3) the exchange of length vector; As interval in the I of sector [0, π/6) interior I ₆Be I _Long, I ₁Be I _ShortIn the interval [π/6, π/3) interior I ₁Be I _Long, I ₆Be I _ShortWhen switching in the sector, I _ShortWant conversion, I _LongConstant; Switch to sector II, I like sector I _ShortBy I ₆Become I ₂, I _LongStill be I ₁I in other each sectors _LongAnd I _ShortTo as shown in Figure 8 in requisition for the thyristor of opening.

Be the operation of realization unity power factor, phase current and phase voltage synchronous operation, this circuit produces the effective vector that needs through the space vector control mode of three-phase electricity flow pattern, and the action time of effective vector.

The voltage of three phase network side such as formula (1) expression:

$\left\{\begin{array}{c}{e}_a=U_s\sin \left(\mathrm{\ωt}\right)\\ e_b=U_s\sin (\mathrm{\ωt}-\frac{2\mathrm{\π}}{3})\\ e_c=U_s\sin (\mathrm{\ωt}+\frac{2\mathrm{\π}}{3})\end{array}\right.---\left(1\right)$

U in the formula _SPeak value for the electrical network phase voltage.

To the sampling of the three-phase voltage of electrical network, confirm the phase angle θ in current employing cycle through digital phase-locked loop, again with π/3 be one-period to phase angle θ delivery number, the remainder that obtains is the phase angle θ ' in the current sector.

${\mathrm{\θ}}^{\′}=\mathrm{\θ}\mathrm{mod}\frac{\mathrm{\π}}{3}---\left(2\right)$

Confirm the action time that current employing point calculates each vector by formula (3) and (4):

When 0≤θ '＜π/6,

$\left\{\begin{array}{c}{T}_{\mathrm{long}}={\mathrm{MT}}_S\sin (\frac{\mathrm{\&pi;}}{3}-{\mathrm{\&theta;}}^{\&prime;})\\ T_{\mathrm{short}}={\mathrm{MT}}_S\sin \left({\mathrm{\&theta;}}^{\&prime;}\right)\\ {\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="HSA00000030503400024.png"\; state="\{\{state\}\}">T</figure-callout>}}_0=T_S-T_{\mathrm{long}}-T_{\mathrm{short}}\end{array}\right.---\left(3\right)$

When π/6≤θ '＜π/3,

$\left\{\begin{array}{c}{T}_{\mathrm{long}}={\mathrm{MT}}_S\sin \left({\mathrm{\&theta;}}^{\&prime;}\right)\\ T_{\mathrm{short}}={\mathrm{MT}}_S\sin (\frac{\mathrm{\&pi;}}{3}-{\mathrm{\&theta;}}^{\&prime;})\\ {\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="HSA00000030503400024.png"\; state="\{\{state\}\}">T</figure-callout>}}_0=T_S-T_{\mathrm{long}}-T_{\mathrm{short}}\end{array}\right.---\left(4\right)$

In the formula, M is a modulation ratio, T _SBe the vector cycle.

Can know according to above analysis, choose the effective vector of each vector in the cycle, calculate action time of each vector, just can obtain the gate electrode drive signals of each power switch component among Fig. 9 by formula (3) and (4) by Fig. 8.E in Fig. 9 _a, e _bAnd e _cBe three-phase alternating-current supply, u _{A ' N '}, u _{B ' N '}And u _{C ' N '}Be the phase voltage on the filter capacitor, i _a, i _bAnd i _cBe the phase current of the three-phase of power supply, i _Sa, i _SbAnd i _ScFor modulate the input current of the rectifier bridge that generates, G through pulsewidth ₁₁～G ₆₁, G ₁₂～G ₆₂, G _T1And G _T2Be respectively thyristor S ₁₁～S ₆₁, S ₁₂～S ₆₂, first, second contrary lead type and controls electronic switch T entirely ₁And T ₂Gate electrode drive signals.The sense of current had been for just when rated current flowed into brachium pontis here, otherwise for bearing.

The switching process of this rectification circuit has three kinds of commutating modes.Figure 10 to Figure 12 is respectively the work wave in adjacent two the vector cycles under three kinds of commutating modes.In Figure 10 to Figure 12, comprise e _a, e _b, e _c, u _{A ' N '}, u _{B ' N '}, u _{C ' N '}, G _T1, G _T2Waveform, and the gate electrode drive signals of each thyristor that need move.

Pattern one is half switching tube commutation course in the sector, and the length vector in this moment in each vector cycle is all constant.Figure 10 with sector I interval [0, π/6) in two vector cycles be that example describes.

At t ₀Moment vector I ₁Effect, S ₁₂, S ₆₁And T ₂Conducting, the line voltage U _{A ' B '}To electric.The physical circuit conduction mode is shown in Figure 13 (a).

At t ₁Moment vector I ₆S is given in effect ₅₁And S ₆₁Driving pulse, the T of conducting simultaneously ₁Pipe is because U _{C ' N '}＞U _{A ' N '}, S ₁₂Bear back-pressure U _{C ' A '}Electric current is arrived S by the change of current ₅₁The line voltage U _{C ' B '}To electric.Phase current switches to the C phase mutually from A.The physical circuit conduction mode is shown in Figure 13 (b).

At t ₂Constantly turn-off T ₂Pipe, S ₅₁And S ₆₁Tube current breaks off; The DC side inductive current passes through the sustained diode afterflow, and powers to the load, to t ₃Moment vector end cycle.T ₁Pipe is at (t ₂～t ₃) in carry out zero-current switching.The physical circuit conduction mode is shown in Figure 13 (c).

Next vector cycle (t ₃～t ₄) the switching tube switching sequence repeat t ₀～t ₁

In pattern one, the turn-off time of thyristor is to not influence of circuit performance.Vector is gone up the length vector in a vector cycle when constant relatively in the cycle, its switching process is all shown in pattern one.

Pattern two be interval in the sector [π/6, π/3) first vector cycle switch pipe commutation course, this moment, the length vector will exchange.Figure 11 with the interval of sector I [0, π/6) last vector cycle and interval [π/6, π/3) first vector cycle be that example describes.

t ₀Moment vector I ₁Effect, S ₁₂, S ₆₁And T ₂Conducting; t ₁Moment vector I ₆Effect, S ₅₁And T ₁Conducting, electric current flows into load mutually from C; t ₂Moment T ₂Turn-off, the net side is not to electric, by the energy storage inductor powering load.t ₂～t ₃T in time ₁Carry out zero-current switching.t ₃Constantly begin to get into interval [π/6, π/3); This moment electrical network phase voltage e _a＞e _c

At t ₃Moment vector I ₆Effect, conducting S ₅₂, S ₆₁And T ₂This moment S ₁₂At t ₁～t ₃Returned to the forward blocking state in time; Otherwise S ₅₂Can't conducting.The physical circuit conduction mode is shown in Figure 14 (a).

At t ₄Moment vector I ₁S is given in effect ₁₁And S ₆₁Driving pulse, the T of conducting simultaneously ₁Pipe is because U _{A ' N '}＞U _{C ' N '}, S ₅₂Bear back-pressure U _{A ' C '}Electric current is arrived S by the change of current ₁₁The line voltage U _{A ' B '}To electric.The physical circuit conduction mode is shown in Figure 14 (b).

At t ₅Constantly turn-off T ₂Pipe, the electric current in the DC side inductance is through the sustained diode afterflow.T ₁Pipe is at t ₅Carry out zero-current switching constantly.The physical circuit conduction mode is shown in Figure 14 (c).

The commutation course of pattern two exist interval in each sector [π/6, π/3) first vector cycle; Concrete switching process is with above analysis.The length vector handoff procedure of pattern two guarantees that after the phase capacitance voltage changes the handoff procedure of space vector modulation still can normally carry out.

The commutation course of short transform vector when pattern three is switched for the sector.Figure 12 is that last vector cycle of sector I and first vector cycle of sector II are that example describes.

t ₀Moment vector I ₆Effect, S ₅₂, S ₆₁And T ₂Conducting; t ₁Moment vector I ₁Effect, S ₁₁And T ₁Conducting, electric current flows into load mutually from A; t ₂Moment T ₂Turn-off the energy storage inductor powering load.T ₁Keep open-minded.t ₃Constantly begin to get into sector II; This moment electrical network phase voltage e _c＜0; I _ShortBy I ₆Become I ₂

At t ₃Moment vector I ₂S is given in effect ₂₂And S ₁₁Driving pulse; Because T ₂Turn-off S ₂₂And S ₁₁Conducting; The line voltage U _{A ' C '}Powering load.The physical circuit conduction mode is shown in Figure 15 (a).

At t ₄Moment vector I ₁S is given in effect ₆₁And S ₁₁Driving pulse, the T of conducting simultaneously ₂, because U _{C ' N '}＞U _{B ' N '}, S ₂₂Bear back-pressure U _{C ' B '}Electric current is arrived S by the change of current ₆₁Load current flows into electrical network B phase.The physical circuit conduction mode is shown in Figure 15 (b).

At t ₅Constantly turn-off T ₁Pipe, dc inductance is through diode D afterflow.T ₂Pipe is at t ₅Carry out zero-current switching constantly.The physical circuit conduction mode is shown in Figure 15 (c).

There is first vector cycle in each sector in the commutation course of pattern three; Concrete switching process is with above analysis.Pattern three has been stipulated the pulse control sequence that the short vector in switching back, sector changes, and has guaranteed that the thyristor of conducting in the module 4 can turn-off under the effect of electric capacity phase voltage.

According to pattern one pulse control sequence, can effectively guarantee current mode space vector control meeting normally execution in based on the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch to pattern three.

During work, will link to each other with control system based on the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch, control system is shown in figure 16, comprises microprocessor, signal deteching circuit, gate drive circuit; The input of microprocessor is connected with the output of signal deteching circuit; The output of microprocessor is connected with the input of gate drive circuit; Input based on the module 1 of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch is connected with the input of signal deteching circuit, and gate drive circuit is controlled electronic switch T against leading type respectively with based on power scr in the module 2 of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch and the module 4 and in the module 3 first, second entirely ₁And T ₂Gate pole connect.

The operation principle of this control system is that on the one hand, signal deteching circuit is through detecting net side phase voltage e _a, e _b, e _cWith phase current i _a, i _b, i _cSignal is sent into computer processor and is carried out computing, after its digital phase-locking is calculated mutually, obtains power-factor angle

Convert into and set current phase angle θ ₀Offset θ ₀, send into phase angle control pi regulator, obtain setting current phase angle θ ₀Signal deteching circuit is through detecting direct voltage E _d, send into computer processor and carry out computing, convert the offset M of modulation ratio into, send into the voltage control pi regulator, obtain modulation ratio M.Can obtain effective vector action time in each vector cycle again according to above-mentioned formula (2)～(4); The driving pulse sequence of each switching tube in next vector cycle is set through computer processor; Automatically send drive signal at the time point that is provided with and give gate drive circuit; Again by gate drive circuit with gate electrode drive signals input each switch element based on the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch, realization is to the control of each power switch component in the rectification circuit.

In the electric control system owing to use three-phase electricity flow pattern PWM rectifier based on two controlled rectification bridges of hybrid switch; Under the current space vector control mode; Realizing to control based on the power switch component of the three-phase electricity flow pattern PWM rectifier of two controlled rectification bridges of hybrid switch, thus keep the power factor of system be 1 with constant DC pressure E _d

The simulation waveform figure of the three-phase electricity flow pattern PWM rectifier of the two controlled rectification bridges that are based on hybrid switch shown in Figure 17.

In conjunction with Fig. 5, the system emulation parameter is: operating frequency is 8kHz, and the input phase voltage is 220V, and output dc voltage is 400V, and load is 100kW, the ac filter inductance L=225uH of net side, ac filter capacitor C=200uF, DC filtering inductance L _d=600uH, dc capacitor C _d=2000uF.

Among Figure 17, upper curve is that A phase voltage waveform, middle curve are that A phase current waveform, lower curve are A phase capacitance voltage waveform.As can be seen from Figure 17, system has kept the unity power factor operation, and simulation study is consistent with the mathematical analysis result.

The present invention can be used on three-phase and realizes the adjustable occasion of High Power Factor direct voltage.Such as: be used for the metal induction heating system, various AC-DC-AC alternating current machine drive systems.It meets the energy-conserving and environment-protective requirement of country, can eliminate reactive power loss cheaply, has realized " green power supply " simultaneously, has the certain social benefit.Along with the extensive use of China industrialized development, particularly frequency converter with to the exploitation of new forms of energy, this patent meets this growing trend, has wide prospect in industrial application and potential market, but considerable economic benefit.

Rectifier of the present invention has overcome the operating frequency of three-phase hybrid switch PWM current mode rectifier of single rectifier bridge to the undue shortcoming that relies on of thyristor characteristics; Make triode thyristor also can have the PWM modulation capability of upper frequency; And kept the few advantage of accessory power supply of the type system; Its circuit topology is succinct, and expensive power controlled switching tube is few, and cost is low; Space vector control makes the switch least number of times of power switch component in the circuit, the efficient of system is improved, and be convenient to control.

Claims (4)

1. based on the multiphase current type PWM rectifier of two controlled rectification bridges of hybrid switch, number of phases M >=2 is characterized in that:

This rectifier is made up of five modules, and wherein module 1 is made up of M group LC filter, and module 2 is respectively thyristor M commutating phase bridge with module 4, module 3 be two independent controls control electronic switch (T entirely against leading type ₁, T ₂), module 5 is the LC filter of band fly-wheel diode;

The input of module 1 (md1_in1, md1_in2 ..., md1_inM) M each phase inlet wire mutually of being connected respectively to electrical network; The output of module 1 (md1_out1, md1_out_2 ..., md1_out_ M) be connected respectively to module 2 and module 4 each mutually the brachium pontis mid point (md2_in1, md2_in2 ..., md2_inM and md4_in1, md4_in2 ..., md4_inM), the M of module 1 filter capacitor end connects into mid point O;

Module 2 positive output end (P ₁) and module 4 positive output end (P ₂) between first contrary lead type and control electronic switch (T entirely of link block 3 ₁), module 2 negative output terminal (N ₁) and module 4 negative output terminal (N ₂) between second contrary lead type and control electronic switch (T entirely of link block 3 ₂), link block 2 positive output end (P ₁) first contrary lead type and control electronic switch (T entirely ₁) and link block 2 negative output terminal (N ₁) second contrary lead type and control electronic switch (T entirely ₂) polarity opposite;

Module 5 positive input terminals (P ') connection module 4 positive output end (P ₂), module 5 negative input ends (N ') connection module 4 negative output terminal (N ₂), the output of the input of module 1 and module 5 is respectively the input and the output of this rectifier.

2. multiphase current type PWM rectifier according to claim 1 is characterized in that: the M group LC filter of forming module 1 is a second order LC filter, or the 2n rank LC filter of n level series connection, n >=2.

3. multiphase current type PWM rectifier according to claim 1 is characterized in that: the LC filter of module 5 band fly-wheel diodes is a second order LC filter, or the 2k rank LC filter of k level series connection, k >=2.

4. multiphase current type PWM rectifier according to claim 1 is characterized in that: first contrary lead type and controls electronic switch (T entirely ₁) and second contrary lead type and control electronic switch (T entirely ₂) be IGBT or IGCT or the IECT that contains the reverse parallel connection diode.

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