CN207368897U - A kind of single-stage isolated type Three-phase PFC - Google Patents

Abstract

The utility model discloses a kind of single-stage isolated type Three-phase PFC, its converter includes primary side input circuit, transformer and secondary output circuit, and the primary side input circuit includes first switch unit, the first rectification unit, second switch unit, series resonance unit；The first switch unit includes three switching groups, and three switching groups are separately positioned in three phase lines of the phase three-wire three power supply of access；Three switching groups are connected by three phase lines with first rectification unit respectively；First rectification unit connects the second switch unit and the series resonance unit concatenated with one another, the primary side of the transformer, the secondary side of the transformer and is connected with secondary output circuit.The utility model has the advantages of simple structure, realizes AC-DC conversion function, Active PFC function, isolated variable, Sofe Switch and voltage regulation function, saves many power rate devices, is suitable for high power density occasion.

Description

A kind of single-stage isolated type Three-phase PFC

Technical field

Power electronics field is the utility model is related to, more particularly to a kind of single-stage isolated type Three-phase PFC.

Background technology

It is to use three phase supply mostly since the capacity of single devices power load in recent years is increasing, for example, it is electronic Vehicle charging station etc., were it not for PFC correcting functions the power quality of power grid will be destroyed it is very big, or even it is serious when can cause The paralysis of power grid, at present, PFC (Active PFC) circuit, including two kinds of booster type (Boost) and voltage-dropping type (Buck), but Booster type or voltage-dropping type PFC translation circuits are either used, if the isolation of output needs or voltage exceed a certain range, Following stage is required to increase level-one DC converter, so for a long time, the ac-dc conversion circuit inputted for three-phase alternating current, Generally PFC+DC/DC two-stage circuits, thus cause whole circuit design complex, therefore are also having external colleague before The three-phase AC/DC conversion device of single-stage was proposed, such as the cycloconverter that everybody is familiar with, wherein in EATON groups Michael Harrison are that more typical high efficient three-phase is handed in the patent of invention WO2008/018802A2 of application in 2007 Single-stage converter is flowed, as shown in Figure 1, the circuit realizes circuit reduction on the basis of traditional three-phase alternating current converter, together When also achieve Sofe Switch, coordinate its control method almost ideal under preferable input condition；But due to the three of physical device Phase input voltage source is simultaneously non-ideal, has a variety of transient electric-energy quality problems, than if any the temporary drop of power grid, surging, frequency The various actual conditions such as saltus step.Since the circuit is overly simplified, conducting can only be a phase switching group every time, and three-phase is successively Samsara, directly circuit is formed after opening by resonant inductance, transformer with the resonant capacitance being respectively connected；Originally it is according to normal The circuit of logic working, in the case where there is saltus step or polarity mutation in input voltage, easily formed reverse spike voltage and Electric current pours in down a chimney, it must terminate work immediately and either be switched fast as corresponding protected mode (or operating mode), otherwise resonance electricity The pressure difference of pressure (or electric current) and input source be easy to cause the damage of switching group, thus its detect protection require it is high, it is corresponding not Same grid condition needs to set different protections and operating mode, and control algolithm certainly will be become extremely complex, converter DSP control unit arithmetic speed and memory space be all limited, therefore the topology apparatus can be too for the condition of power grid Cross sensitivity, grid adaptability is poor in other words, so as to cause reliability poor, can not large-scale quantify production, this be also to The present loses the reason for technology promotes the use of product on a large scale.Therefore, we are necessary summarizing the technology base of every older generation On plinth, redesign and invent a kind of circuit and go to realize high efficiency, high power density and high reliability.

The disclosure of background above technology contents is only used for inventive concept and the technical solution that auxiliary understands the utility model, its Not necessarily belong to the prior art of present patent application, show the above in the Shen of present patent application in no tangible proof Please day it is disclosed in the case of, above-mentioned background technology should not be taken to evaluation the application novelty and creativeness.

The content of the invention

The utility model aim is to propose a kind of single-stage isolated type Three-phase PFC, to solve the above-mentioned prior art The limited technical problem of existing complicated caused application.

For this reason, the utility model also proposed a kind of single-stage isolated type Three-phase PFC, including primary side input circuit, Transformer and secondary output circuit, the primary side input circuit include first switch unit, the first rectification unit, second switch list Member, series resonance unit；The first switch unit includes three switching groups, and three switching groups are separately positioned on access In three phase lines of phase three-wire three power supply；Three switching groups are connected by three phase lines and first rectification unit respectively Connect；First rectification unit connects the second switch unit and the series resonance unit concatenated with one another, the transformation The primary side of device, the secondary side of the transformer are connected with secondary output circuit；First rectification unit performs AC rectification Operation, the transformer perform isolation and become press operation, and the switching group is both used to perform AC power factor correction switch behaviour Make, and coordinate the series resonance unit, the transformer and the second switch for performing reverse resonance channel selector operation Unit completes the function of series resonance translation circuit together.

Preferably, the utility model can also have following technical characteristic：

The first switch unit includes the first power switch and the second power switch；First power switch and described Second power switch is driven by the same driving unit, same drive signal；First power switch and The source electrode of second power switch is oppositely arranged

The first switch unit includes the first power switch and the second power switch, first power switch and described Second power switch is driven each via the independent driving unit, drive signal；First power switch and institute The source electrode for stating the second power switch is disposed opposite to each other.

The secondary output circuit includes the second rectification unit, and second rectification unit can be whole for voltage multiplying rectifier, all-wave Stream or full-bridge rectification.

The secondary output circuit further includes energy storage afterflow unit, and the energy storage afterflow unit is not provided with afterflow inductance, if Put filter capacitor, the filter capacitor and second rectification unit simultaneously connect；Or the energy storage afterflow unit set it is at least one Afterflow inductance and at least one filter capacitor, at least one afterflow inductance concatenated with one another and at least one filtered electrical Appearance is connected with second rectification unit.

The primary side input circuit further includes input filter, and the input filter is arranged on the first switch unit Front end, phase three-wire three power supply access the first switch unit after input filter filters.

First power switch, second power switch and the second switch unit are managed for metal-oxide-semiconductor or IGBT.

The series resonance unit includes at least one resonant inductance and at least one resonant capacitance, the resonant inductance with The resonant capacitance is connected in series.

Meanwhile the utility model also proposed a kind of single-stage isolated type Three-phase PFC, including at least two such as take up an official post Pfc converter described in one, is connected with parallel or crisscross parallel between each pfc converter.

The beneficial effect that the utility model is compared with the prior art includes：

From structure, the utility model changes the implementation method that traditional pfc circuit adds DC isolation translation circuit, leads to The topological structure of the utility model is crossed, the energy-storage units after the AC rectification of conventional AC/DC convertor can be saved, while The power device and drive circuit of DC isolation conversion can be saved, whole ac-dc conversion circuit is simple, and control logic is simplified, It is efficient, it is suitable for high efficiency and high power density demand occasion；Functionally, Active PFC is carried relative to traditional For the isolated form three-phase AC/DC conversion device of function, AC-DC conversion function, power are achieved that by primary conversion circuit Factor correction function, isolated variable, Sofe Switch and voltage regulation function, can save many power rate devices, while compared to preceding The Cycloconverter mentioned is stated, since the input of phase three-wire three power supply can be formed into a loop between the two phases, conducting every time No longer it is a phase switching group, the situation that saltus step or polarity mutation occurs in input voltage can be successfully managed, its grid adaptability is more By force, job stability higher, equipment quality are relatively reliable.

Brief description of the drawings

Fig. 1 is existing high efficient three-phase exchange single-stage converter (cycloconverter) structure diagram.

Fig. 2 is the schematic diagram of the isolated form Three-phase PFC of the utility model embodiment 1.

Fig. 3 is that the three-phase voltage waveform signal of the utility model embodiment 1 and joint define schematic diagram.

Fig. 4 be the utility model embodiment 1 AC-BC sections AB to conducting circuit diagram.

Fig. 5 is the AC-BC interval B C phase continuous current circuit schematic diagrames of the utility model embodiment 1.

Fig. 6 is the AC-BC sections AC phase continuous current circuit schematic diagrames of the utility model embodiment 1.

Fig. 7 is the AC-BC sections inductive current continuous current circuit schematic diagram of the utility model embodiment 1.

Fig. 8 is that the AC-BC sections Q7 of the utility model embodiment 1 leads the reverse freewheeling current path schematic diagram of figure.

Fig. 9 is the equivalent transformation signal 1 of the utility model embodiment 1.

Figure 10 is the equivalent transformation signal 2 of the utility model embodiment 1.

Figure 11 is the equivalent transformation signal 3 of the utility model embodiment 1.

Figure 12 is the equivalent transformation signal 4 of the utility model embodiment 1.

Figure 13 is the sequence diagram of each drive signal under 12 segments in the utility model embodiment 1.

The structure diagram of the variant embodiment 2 of Figure 14 the utility model embodiments 1.

Figure 15 is the structure diagram of the variant embodiment 3 of the utility model embodiment 1.

Figure 16 is that the secondary output circuit of the utility model embodiment 1 does not have the structure diagram of afterflow inductance.

Embodiment

With reference to embodiment and compare attached drawing the utility model is described in further detail.It should be emphasized that It is, what the description below was merely exemplary, rather than in order to limit the scope of the utility model and its application.

With reference to the following drawings, non-limiting and nonexcludability embodiment will be described, wherein identical reference numeral represents Identical component, unless stated otherwise.

Embodiment 1：

As shown in figure 4, the present embodiment proposes a kind of single-stage isolated type Three-phase PFC, including primary side input circuit, Transformer and secondary output circuit, the primary side input circuit include first switch unit, the first rectification unit, second switch list Member, series resonance unit；The first switch unit includes three switching groups, and three switching groups are separately positioned on access In three phase lines of phase three-wire three power supply；Three switching groups are connected by three phase lines and first rectification unit respectively Connect；First rectification unit connects the second switch unit and the series resonance unit concatenated with one another, the transformation The primary side of device, the secondary side of the transformer are connected with secondary output circuit；First rectification unit performs AC rectification Operation, the transformer perform isolation and become press operation, and the switching group is both used to perform AC power factor correction switch behaviour Make, and coordinate the series resonance unit, the transformer and the second switch for performing reverse resonance channel selector operation Unit completes the function of series resonance translation circuit together.

As shown in Fig. 2, phase three-wire three power supply includes A phases, B phases and C phases, the voltage signal of three of them phase line refers to figure 3,120 degree of phase is differed each other, since the power supply signal that actually enters is there may be saltus step or polarity mutation, so The voltage waveform for implementing to exemplify for the ease of describing hereinafter, with the waveform of standard as reference.Primary side input circuit further includes Input filter, the input filter are arranged on first switch unit front end, and phase three-wire three power supply is filtered through input filter First switch unit is accessed afterwards, in order to be greatly attenuated the EMI signal being passed to through power supply, protects equipment from its evil, such as Fig. 2 institutes Show, the present embodiment is electromagnetic interface filter in the input filter of phase three-wire three input terminal, sets electromagnetic interface filter also can effectively control The EMI signal that control equipment produces in itself, prevents that it from entering power grid, pollutes electromagnetic environment, endanger other equipment, the present embodiment its In his alternative embodiments, other kinds of wave filter can also be.

The outlet side of electromagnetic interface filter is connected to first switch unit, and three switching groups of first switch unit are two-way opened Close, including the semiconductor power switch (the first power switch and the second power switch) that two high frequencies are opened, as shown in Fig. 2, A phases Upper to include including including switching group Q5Q6 in switching group Q3Q4, C phase in switching group Q1Q2, B phase, which can be with Managed for metal-oxide-semiconductor, IGBT, it should be appreciated by those skilled in the art to the utility model is not limited to above two semiconductor work( Rate switchs, and can also be the power component of other executable switching manipulations.A, do not shared between the respective switching group of B, C phase same One driving power and same drive signal；Two semiconductor power switch in same phase can share a driving power With same drive signal, each can also independently drive.By taking metal-oxide-semiconductor as an example, when the source electrode of two metal-oxide-semiconductors is oppositely arranged, A driving power and same drive signal can be shared；, can be each independent when the source electrode of two metal-oxide-semiconductors is disposed opposite to each other Driving.Sharing a driving power and same drive signal can make it that the structure of the present embodiment is simpler, it is not necessary to set Too many driving unit, for the of a relatively high place of finite volume or cost requirement, has direct advantage.

As shown in Fig. 2, the first rectification unit be full-bridge type rectifier, including set bridge arm on 6 diode D1, D2, D3, D4, D5, D6, the anode-side of diode D1 and the cathode side of D4 are connected with A phase lines, the anode-side of D2 and the cathode of D5 Side is connected with B phase lines, the cathode side of the anode-side of D3 and D6 are connected with C phase lines.

First rectification unit is connected with second switch unit Q7, can perform the switching manipulation of reverse resonance；Transformer Tra's Primary side is connected with series resonance unit, and series resonance unit includes resonant inductance Lr and resonant capacitance Cr, second switch unit Q7 is in parallel with series resonance unit and transformer primary side, source side and diode D4, D5 and D6 of second switch unit Q7 Anode-side connects, and the drain side of second switch unit Q7 is connected with the cathode side of diode D1, D2, D3；Second switch unit is same Sample is the semiconductor power switch that high frequency is opened, and can equally be managed for metal-oxide-semiconductor, IGBT, it should be appreciated by those skilled in the art Arrive, the utility model is not limited to above two semiconductor power switch, can also be the work(of other executable switching manipulations Rate element.Meanwhile in the present embodiment, as shown in figure 4, the diode of the first rectification unit and first switch unit etc. is parasitic simultaneously Connection capacitance parameter is equivalent to Cp and shows in circuit, it is preferred that when the Cp is less, can also optionally increase, So as to the vibration spike in suppression circuit.

Series resonance unit can include being not limited to the resonant inductance Lr and resonant capacitance Cr of one, the one of the present embodiment In a little alternative embodiments, resonant inductance Lr and can be multiple with resonant capacitance Cr.

As shown in Fig. 2, the two level side of transformer Tra, as soon as it is a typical full bridge rectifier, few narration herein, Including diode D11, D12, D13, D14, and afterflow inductance L2, filter capacitor C2, in the present embodiment, the secondary side of transformer Can be with other rectification circuits, such as voltage multiplying rectifier, full-wave rectification and full-bridge rectification；Afterflow inductance L2, filter capacitor C2 are constituted The energy storage afterflow unit of secondary side, energy storage afterflow unit can be not provided with afterflow inductance L2, only set filter capacitor C2, the filtering Capacitance C2 and the second rectification unit simultaneously connect, or set at least one afterflow inductance L2 and at least one filter capacitor C2, go here and there each other At least one afterflow inductance L2 connect is connected with least one filter capacitor C2 with the second rectification unit.

As shown in figure 3, input A represents input A phases (Phase A), input B represents input B phases (Phase B), inputs C generations Table input C phases (Phase C)；If three-phase voltage differs 120 °, and it is sinusoidal voltage, every 360 ° one is followed in order to facilitate description Ring；In view of stating intuitive and convenient, with 30 ° to 390 ° (30 ° of points in next cycle) for a complete cycle, therefore such as Fig. 5 institutes Show, each joint is respectively defined as AC (30 °), BC (90 °), BA (150 °), CA (210 °), CB (270 °), AB (330 °), AC (30°/390°)；Zero crossing is designated as " O " point.If output voltage is less than the maximum voltage difference in certain two-phase of any time, because This voltage-dropping type operation principle is set up.

Therefore, if since AC points, to BC points, AC-BC sections, section A phases are higher than C with B phase voltage amplitudes absolute value Phase, if three roads apply PWM drive signal, A phases and D1 in the circuit of B phases at the same time, D5 is turned on by positive bias-voltage, and C phases D3 And D6 cannot be turned on by reversed bias voltage, as shown in figure 4, Q1Q2, Q3Q4 are turned on, electric current passes through first switch unit and D1, Lr, Tra, Cr, D5 are formed into a loop.When the driving either driving closing of Q3Q4 of Q1Q2, then D3 or D6 can be turned on by positive bias-voltage Form freewheeling path with resonant inductance Lr, in order to ensure PF values, C phases can only with the voltage turn-on of opposite direction amplitude, therefore together First close to that phase voltage of amplitude (such as then closed in 30 ° -60 ° or AC-O sections, the driving of A phases prior to B, such as Fig. 5, Electric current is formed into a loop by first switch unit and D3, Lr, Tra, Cr, D5.60 ° -90 ° or O-BC sections, the driving of B phases are then first Closed in A, such as Fig. 6, electric current is formed into a loop by first switch unit and D1, Lr, Tra, Cr, D6.), the PWM first closed drives We are denoted as " small " to dynamic model formula, and the PWM drive patterns turned off afterwards are denoted as " big ".

After the PWM driving voltages of AB two-phases are all closed, therefore inputting three-phase alternating current does not have any circuit to turn on, at this time before Electric current meeting nature afterflow in the circuit of phase conducting, the energy moment of wherein Cp completes release, if C phase driving voltages are still deposited , at this time, as shown in fig. 7, electric current then can by D2+D5+Q7 (anti-and diode) or D1+D4+Q7 (anti-and diode) into Row afterflow；If C phases driving voltage is low level, inductive current can pass through D1+D4+Q7 (anti-and diode) or D2+D5+ Q7 (anti-and diode) or D3+D6+Q7 (anti-and diode) carry out afterflow.

According to above operation principle, if the drivings of C phases is kept to there is (high level) always, or more than or equal to other two Such a driving condition, can be abbreviated as " height " by the driving voltage of maximum PWM in phase, i.e., only need at this time the drivings of AB two-phases according to Control needs the corresponding high-frequency PWM drive signal of hair to realize the step-down rectifier of three-phase voltage, can simplify in the segment Driving logic control method to first switch unit, while turn-on consumption can also be reduced；Meanwhile in the segment, each phase Electric current can turn on, and be not in certain phenomenon that mutually stops in uncontrollable rectifier with arc in phase.Therefore driving unit PWM drive signal is modulated, it is possible to so that current waveform follows unanimously with voltage waveform, therefore can obtain higher PF values, that is, realize PFC correcting functions.

After Q7 completes afterflow, apply high level drive signal to Q7 at this time, due to resonant inductance Lr, Cr and transformer The presence of primary side, thus electric current quickly can reverse resonance, as shown in figure 8, electric current is into crossing Q7, Lr, Cr and transformer once Side forms reverse resonant tank.Turned off according to control needs, then by Q7, cut off the path, while open first switch unit, made The threephase AC electric energy forming circuit of input.

Each operating mode can carry out equivalent transformation to the circuit of the converter of this single-stage isolated type above：

As shown in figure 9, being simplified according to symmetry and switch functionality when the first switch unit conducting of certain two-phase Afterwards such as Figure 10, the alternating current source for having diode under transient condition can be equivalent to DC source at this moment, while first switch unit also may be used To be equivalent to a switch, therefore as shown in figure 11., can be with since Cp is foregoing each switching tube and diode parasitic capacitance It is equivalent to ignore, as shown in figure 12.

Carry out it is above-mentioned it is equivalent after, the actual series resonant circuit (LLC circuits) that can be regarded as an isolated form of the circuit, In conclusion whole work of input first switch unit can be in equivalent serial resonant circuit diagram a work bridge arm, Q7 is then Represent another pattern, if it is desired to which the shut-off of Q7 is Sofe Switch or close to Sofe Switch, then should try one's best makes the of input terminal One switch element duty cycle is no more than 50%, and is approached with the duty cycle of Q7.So in " PWM " pattern in ABC three-phases most Big space rate is 50% or so.So the maximum duty cycle most preferably 0.5 of the first switch unit of input, with second switch unit Q7 forms complementation, and realizes output voltage stabilization by adjusting frequency, when input voltage exceedes a certain range or underload When, then by the maximum duty cycle of the first switch unit of input most preferably reduce or deviate 0.5；As shown in figure 16, afterflow electricity Sense L2 may or may not be present, if the duty cycle of first switch unit is always below 0.5, have the afterflow inductance for most It is good.

It can be seen that the converter circuit of this isolated form realizes the similar principles of series resonant circuit, simultaneously because first switch The Active PFC function that unit plays, that is to say, that this converter, is just realized by single stage circuit structure and control method Multiple functions, eliminate many power components, while realize Sofe Switch again, and the loss of switch is smaller, are adapted to high power close The occasion of degree, the converter circuit of this isolated form can utilize the similar principles of series resonant circuit, change working frequency, so as to To realize that voltage stabilizing of the secondary output circuit under different loads and different input voltages exports, when input and loading condition deviate After certain frequency shift scope, the mode for changing duty cycle is recycled to be adjusted, to ensure maximum Sofe Switch Work.

Compared to existing Cycloconverter, single-stage converter conception is equally realized, it is more intersecting than traditional three Circuit reduction is realized on the basis of current converter, while also achieves Sofe Switch, the utility model is not only handed in preferable three-phase It can be worked normally under stream input condition, since three switching groups of first switch unit can meet any three-phase alternating current input condition Under, when the three-phase alternating-current supply of input will can pass through resonant inductance Lr, transformer, Cr forming circuits, at least need two-phase switch Group is opened, so in the case where saltus step or polarity mutation occurs in input voltage, it is not easy to form reverse spike voltage and electricity Stream pours in down a chimney, and requires small to detecting protection, the algorithm of control can be simpler, it is really promoted reference on a large scale.

To sum up, from structure, the utility model changes the realization side that traditional pfc circuit adds DC isolation translation circuit Method, by the topological structure of the utility model, can save the energy-storage units after the AC rectification of conventional AC/DC convertor, together When can also save DC isolation conversion power device and drive circuit, whole ac-dc conversion circuit is simple, control logic Simplify, it is efficient, it is suitable for high efficiency and high power density demand occasion；

Functionally, relative to traditional isolated form three-phase AC/DC conversion device with Active PFC function and Speech, by primary conversion circuit be achieved that AC-DC conversion function, Active PFC function, isolated variable, Sofe Switch with And voltage regulation function, many power rate devices can be saved, while compared to the Cycloconverter being previously mentioned, due to three-phase The input of three line power supplys can be formed into a loop between the two phases, and conducting is no longer a phase switching group every time, can successfully manage input There is the situation of saltus step or polarity mutation in voltage, its grid adaptability is stronger, and job stability higher, equipment quality more may be used Lean on.

From control, the arithmetic speed of DSP control unit with simplify control algorithm, can be improved, is grasped from the switch of PFC functions From the point of view of making, by applying the drive signal of " height " driving condition to one of switching group, PWM is carried out to other two switching groups The drive signal of driving condition, thus, can simplify control method, realize high PFC, low THDI.From coming for the angle of Sofe Switch See, it is only necessary to adjust first switch unit and second switch unit for 0.5.From the angle of load, because realizing series resonance The function of circuit, so using the similar principles of series resonant circuit, changes working frequency, so as to realize that secondary exports Voltage stabilizing output of the circuit under different loads and different input voltages, when input and loading condition deviate certain frequency shift After scope, the mode for changing duty cycle is recycled to be adjusted, to ensure that maximum Sofe Switch works.

For other segments, and so on, BC-BA sections, the drive signals of B phases is high driving condition, AC two The drive signal of phase is PWM drive signal, BC-O sections, and the driving of C phases is then closed prior to A, O-BA sections, the driving of A phases Then closed prior to C；

BA-CA sections, the drive signals of A phases are high driving condition, and the drive signals of BC two-phases is PWM drive signal, BA- O sections, the driving of B phases are then closed prior to C, and O-CA sections, the driving of C phases is then closed prior to B.

CA-CB sections, the drive signals of C phases are high driving condition, and the drive signals of AB two-phases is PWM drive signal, CA- O sections, the driving of A phases are then closed prior to B, and O-CB sections, the driving of B phases is then closed prior to A.

CB-AB sections, the drive signals of B phases are high driving condition, and the drive signals of AC two-phases is PWM drive signal, CB- O sections, the driving of C phases are then closed prior to A, and O-AB sections, the driving of A phases is then closed prior to C.

AB-AC sections, the drive signals of A phases are high driving condition, and the drive signals of BC two-phases is PWM drive signal, AB- O sections, the driving of B phases are then closed prior to C, and O-AC sections, the driving of C phases is then closed prior to B.

, can only basis there are the change of phase, amplitude, direction since three-phase voltage might not be completely preferable in reality Actual lock mutually judges to produce the drive waveforms of each segment, therefore should be judged with the feature of each drive waveforms of segment, Without being represented with desired angle, according to the characteristics of three phase mains signal, be segmented into six segments, six segments according to Above-mentioned principle, the waveform logic table such as following table of the first drive signal, the second drive signal and the 3rd drive signal, wherein, same Under one segment, " height " is the first drive signal, other two PWM drive signals are the second drive signal and the 3rd driving letter Number, in conclusion the drive signal waveform logical table for Q1Q2, Q3Q4, Q5Q6 in a cycle.

Table one, drive waveforms logical table

It can be obtained according to each segment of drive waveforms logical table, can perform following control method：

Input/output condition is detected, judges whether input/output condition meets operating condition, the condition of being unsatisfactory for continues waiting for； If meeting condition, start to work, it is necessary to carry out lock phase processor to the phase three-wire three power supply voltage signal of input, judge three-phase three Phase and segment residing for the current time of line power supply；To in the first switch unit under current interval section, corresponding to voltage Switching group on one phase line of amplitude absolute value minimum, applying control, it is constantly in the first of conducting state in segment Drive signal, and apply the second drive signal for carrying out PWM controls and the 3rd driving letter to the switching group on other two phase line Number, and the fourth drive signal of PWM controls is carried out to second switch unit so that conducting can be formed between phase three-wire three power supply Circuit, and when not forming conducting circuit, afterflow and reverse resonance are realized by second switch unit.

The second drive signal, the 3rd drive signal and the fourth drive signal of PWM controls are carried out, further according to voltage signal 6 original segments are divided into 12 segments, duty ratio corresponding are performed according to this 12 segments by zero crossing " O " Drive signal, as shown in figure 13, by taking ACO segments as an example, first drive of " height " driving condition is can perform for the switching group of C phases Dynamic signal so that the phase line is constantly on；For the switching group on other two phase line, it is inconsistent that duty cycle each other will be accommodated PWM drive signal, in this segment, the PWM drive signals of B phases is the 3rd drive signal of " big " driving condition, A phases PWM drive signal is second drive signal of " small " driving condition, and as shown in figure 13, the 3rd drive signal duty cycle is more than second The duty cycle of drive signal, can realize that the switching group of A phases is first closed, be closed after the switching group of B phases, to keep working as A, B, C three-phase First switch unit accommodated PWM drive signal after, A, B, C of the three-phase alternating current of input can be orderly between different phase roads Different circuits is switched to, avoids uniline from accessing, improves power grid adaptive faculty, and forms afterflow, realizes PFC functions；Meanwhile It can realize and be turned off in A phases and B phases, after the switching group of A phases and B phases is turned off, although the switching group of C phases keeps open-minded, But it cannot be formed into a loop the three-phase alternating-current supply of input, at this time, with " big " driving condition, i.e., second switch unit be applied With the fourth drive signal of the 3rd drive signal complementation, when that cannot be formed into a loop the three-phase alternating-current supply of input, 4 wheel driven Dynamic signal turns on after causing Q7 afterflows, forms reverse resonance path, so as to form LLC circuits, forms Sofe Switch, reduces power member The switching loss of part；Each switching group and second switch unit the first drive signal, the second drive signal, the 3rd drive signal and Under the control of fourth drive signal, corresponding switching manipulation is realized.As shown in figure 13, the sequential under 12 different sections is summarized Figure, adjusts different segments the duty cycle of driving, i.e.,：

In the segment, in other two phase line, voltage direction and that phase of voltage magnitude absolute value minimum Switching group on the identical phase line of circuit applies second drive signal, described in the different switching group of voltage direction applies 3rd drive signal, the duty cycle of second drive signal are less than the duty cycle of the 3rd drive signal, and the described 4th The duty cycle of drive signal is identical with the duty cycle of the 3rd drive signal.

It can be carried out using the above method according to following alternating mode：

If three switching groups that some time inscribes first switch unit are both turned on, then second switch unit cannot turn on, this Pass through rectification unit, series resonance unit, transformation between two phase lines where two switching groups that PWM described in Shi Jinhang is controlled The primary side forming circuit of device；

During subsequent time, continue to control the second switch unit to be not turned on, by the first switch unit, voltage side Closed to the switching group on a phase line identical with the phase line of voltage magnitude absolute value minimum, the different switch of voltage direction Group maintains conducting so that maintains between a phase line of conducting and a phase line of voltage magnitude absolute value minimum by rectification list Member, the primary side forming circuit of series resonance unit, transformer；

Go successively to next moment, second switch unit, series resonance unit, transformer primary side afterflow after control The second switch unit conducting, the switching group that last moment maintains conducting is closed, the switching group for carrying out PWM controls at this time is equal Close, be formed into a loop by the primary side of second switch unit, series resonance unit, transformer.

Subsequent time, closes second switch unit, will be identical with a phase voltage direction of voltage magnitude absolute value minimum The switching group of one phase line remains turned-off, and voltage direction difference switching group turns on again, the phase line and voltage turned on again It is formed into a loop between one phase line of amplitude absolute value minimum.

Subsequent time is entered back into, second switch unit is closed, by the phase voltage direction with voltage magnitude absolute value minimum The switching group of an identical phase line is opened, and voltage direction difference switching group is kept it turned on, and at this time, the switching group on three-phase is opened Open, be formed into a loop between two phase lines where two switching groups of progress PWM controls, thus circulate.

Corresponding A CO segments, when just starting, Q7 is closed, and A phases and B are conducted, and is formed into a loop；Immediately, since A phases drive Signal dutyfactor is small, and A phases are first closed, and B phases are conducted with C, and Q7 continues to close at this time；Then, both are turned off, into afterflow shape State, Q7 is opened after afterflow；Since B phase drive signal duty cycles are big, subsequent B phases are first opened, and B phases are conducted with C, forming circuit, Q7 is closed at this time；Subsequent A phases and B phases are opened, and A phases and B are conducted, and Q7 continues to close at this time；So circulation, until ACO areas Between section terminate, into after next segment, according to the characteristics of OBC segments, change duty cycle.

The high driving condition of first drive signal is existing high level always, or first drive signal is PWM drive signal, its driving voltage are more than the driving voltage of second drive signal and the 3rd drive signal；Driven on " height " It is high level always that dynamic state, which is, or depends primarily upon output loading with the duty cycle of " big " state consistency, its otherness exists In influence of the relative fluctuation to load of output voltage, the present embodiment is isolated form load, then " high " state can always be High level or with the PWM drive signal of " big " state consistency.

Embodiment 2：

As shown in figure 14, the present embodiment proposes a kind of variant embodiment of the pfc converter according to embodiment 1, two Isolated form Three-phase PFC parallel connection (or crisscross parallel) signal, it is right respectively by control method described described in embodiment 1 At least two Three-phase PFCs being connected in parallel are controlled, and the present embodiment can be equivalent to series resonant half bridge, work as converter A with and converter B drive signals half of high frequency period of work schedule misphase, then be crisscross parallel, can so make front end Continuous input current, and improve EMI.

Embodiment 3：

As shown in figure 15, the present embodiment proposes a kind of variant embodiment of the pfc converter according to embodiment 1, two Either the isolated form Three-phase PFC of the above is in parallel or crisscross parallel is illustrated, and passes through controlling party described described in embodiment 1 Method is respectively controlled the Three-phase PFC that at least two are connected in parallel, and the present embodiment can be equivalent to series resonant full bridge, Half of high frequency period of operating phase misphase of converter A and converter B, while Q7A and Q7B is respectively 50% duty cycle, so A roads First switch unit (Q1AQ2A, Q3AQ4A, Q5AQ6A) conducting when be formed into a loop by Q7B, B roads first switch unit (Q1BQ2B, Q3BQ4B, Q5BQ6B) is formed into a loop when conducting by Q7A.

It would be recognized by those skilled in the art that it is possible that numerous accommodations are made to above description, so embodiment is only For describing one or more particular implementations.

Although having been described above and describing the example embodiment for being counted as the utility model, those skilled in the art will be bright In vain, it can be variously modified and replaced, without departing from the spirit of the utility model.Repaiied furthermore it is possible to make many Change so that particular case to be fitted to the religious doctrine of the utility model, without departing from the utility model central concept described here. So the utility model is not only restricted to specific embodiment disclosed here, but the utility model may further include and belong to this practicality All embodiments and its equivalent of new scope.

Claims (9)

1. A kind of 1. single-stage isolated type Three-phase PFC, it is characterised in that：It is defeated including primary side input circuit, transformer and secondary Go out circuit, the primary side input circuit includes first switch unit, the first rectification unit, second switch unit, series resonance list Member；The first switch unit includes three switching groups, and three switching groups are separately positioned on the phase three-wire three power supply of access Three phase lines on；Three switching groups are connected by three phase lines with first rectification unit respectively；Described first is whole Flow unit and connect the second switch unit and the series resonance unit concatenated with one another, the primary side of the transformer, institute The secondary side for stating transformer is connected with secondary output circuit.
2. 2. Three-phase PFC as claimed in claim 1, it is characterised in that：The first switch unit includes the first power Switch and the second power switch；First power switch and second power switch by the same driving unit, Same drive signal is driven；The source electrode of first power switch and second power switch is oppositely arranged.
3. 3. Three-phase PFC as claimed in claim 1, it is characterised in that：The first switch unit includes the first power Switch and the second power switch, first power switch and second power switch are each via the independent driving list Member, drive signal are driven；The source electrode of first power switch and second power switch is disposed opposite to each other.
4. 4. Three-phase PFC as claimed in claim 1, it is characterised in that：The secondary output circuit includes the second rectification Unit, second rectification unit can be voltage multiplying rectifier, full-wave rectification or full-bridge rectification.
5. 5. Three-phase PFC as claimed in claim 4, it is characterised in that：The secondary output circuit further includes energy storage and continues Unit is flowed, the energy storage afterflow unit is not provided with afterflow inductance, sets filter capacitor, the filter capacitor and second rectification Unit simultaneously connects；It is concatenated with one another or the energy storage afterflow unit sets at least one afterflow inductance and at least one filter capacitor At least one afterflow inductance is connected with least one filter capacitor with second rectification unit.
6. 6. Three-phase PFC as claimed in claim 2, it is characterised in that：The primary side input circuit further includes input filter Ripple device, the input filter are arranged on the first switch unit front end, and phase three-wire three power supply is after input filter filters Access the first switch unit.
7. 7. Three-phase PFC as claimed in claim 2 or claim 3, it is characterised in that：First power switch, described second Power switch and the second switch unit are managed for metal-oxide-semiconductor or IGBT.
8. 8. Three-phase PFC as claimed in claim 1, it is characterised in that：The series resonance unit includes at least one Resonant inductance and at least one resonant capacitance, the resonant inductance are connected in series with the resonant capacitance.
9. A kind of 9. single-stage isolated type Three-phase PFC, it is characterised in that：Including at least two such as any institutes of claim 1-8 The pfc converter stated, is connected with parallel or crisscross parallel between each pfc converter.