CN207368870U

CN207368870U - A kind of non-isolation type Three-phase PFC

Info

Publication number: CN207368870U
Application number: CN201721332595.6U
Authority: CN
Inventors: 李伦全; 郑车晓; 周涛
Original assignee: SHENZHEN BOYN ELECTRIC Co Ltd
Current assignee: SHENZHEN BOYN ELECTRIC Co Ltd
Priority date: 2017-10-16
Filing date: 2017-10-16
Publication date: 2018-05-15
Anticipated expiration: 2027-10-16

Abstract

The utility model discloses a kind of non-isolation type Three-phase PFC, wherein converter includes switch element, rectification unit and energy storage afterflow unit, switch element 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 rectification unit respectively；Energy storage afterflow unit includes the first to the second afterflow inductance and filter capacitor, the positive terminal of rectification unit is connected by positive electrode bus with first afterflow inductance one end, negative pole end is connected by negative electrode bus with second afterflow inductance one end, it is equipped with filter capacitor between positive electrode bus and negative electrode bus, the other end of the other end of the first afterflow inductance and the second afterflow inductance is connected with the both ends of filter capacitor respectively.The utility model is simple in structure, and control logic is also more simplified, therefore fairly obvious in high power density occasion, advantage.

Description

A kind of non-isolation type Three-phase PFC

Technical field

Field of power electronics is the utility model is related to, more particularly to a kind of non-isolation 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.

For a long time, for PFC (Active PFC) circuit of three-phase alternating current input, usually with (boost) type that boosts Based on (such as Fig. 1), be three-level structure, two capacitance midpoint potentials and the current potential at power grid midpoint are essentially identical, pass through two-way switch The electric current of corresponding phase is controlled respectively.The current amplitude increase for the correspondence phase closed is switched, is corresponded to when switching off on bridge arm Diode current flow circuit, reduces in the electric current under the action of output voltage on Boost inductance, so as to fulfill the control to electric current System.But Boost booster type output voltages are higher, it not can guarantee that PF (power factor (PF)) values and THDI (Current harmonic distortion sum) refer to Mark is preferable, and as inputted nominal phase three-wire three 380VAC, output is general all in 720V or so, or even in 800V, and conventional property Can preferable power tube in below 650V, occur the novel switched devices such as the SIC of the slightly higher 1200V of voltage or so in recent years, It is but with high costs；Therefore, the DC converter of rear end is confined to the finiteness of power device, to take into account efficiency and other factors, Deal with more troublesome.It is drop for this reason, there is an urgent need to seek to meet power quality and the low pfc circuit of voltage Pressure type PFC, thus everybody except in addition to more typical boost type pfc circuit is continuing with, also begin to explore decompression (BUCK) formula Pfc converter.

As shown in Fig. 2, in 2012 in 27 IEEE applied power electronics fair (Annual IEEE Applied Power Electronics Conference and Exposition (APEC 2012) 27th) on deliver the paper of issue 《Swiss rectifier—A novel three-phase buck-type PFC topology for Electric Vehicle battery charging》, more typical buck pfc circuit is described in recent years, wherein more typical SWiSS RECTIFER circuits, it is innovated and has been developed compared to 6-switch buck-type pfc circuits (Fig. 3), its sound Claim loss lower, it is more efficient.From the point of view of careful analysis, really by reducing the rotation of HF switch pipe, and return in electric current The quantity of switching device in road, which is reduced, can realize its improvement claimed, but of a relatively high in finite volume or cost requirement Place, which also has its some limitations, special as the quantity of power device is more (Fig. 2 is 16, and Fig. 3 is 12) It is not switching tube, since the current potential of each switching tube (or switch element) is different, it is required for an independent driving power, Therefore driver circuit is more and complicated, from doing for the angle of actual product, Swiss rectifier and 6-switch buck- Type PFC in control and cost compared to not having too big advantage, especially in the higher occasion of power density requirements, instead Because number of devices increases as inferior position.

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 non-isolation type Three-phase PFC, is deposited with solving the above-mentioned prior art It is complicated caused by be not suitable for asking in the technology that the of a relatively high place of finite volume or cost requirement is applied Topic.

For this reason, the utility model proposes a kind of non-isolation type Three-phase PFC, including switch element, rectification unit and Energy storage afterflow unit, the switch element include three switching groups, and three switching groups are separately positioned on the three-phase three of access In three phase lines of line power supply；Three switching groups are connected by three phase lines with the rectification unit respectively；The energy storage Afterflow unit includes the first to the second afterflow inductance and filter capacitor, and the positive terminal of the rectification unit passes through positive electrode bus and the One afterflow inductance one end is connected, and negative pole end is connected by negative electrode bus with second afterflow inductance one end, and the positive electrode bus is with bearing The other end of the filter capacitor, the other end of the first afterflow inductance and the second afterflow inductance is equipped between the busbar of pole The both ends with the filter capacitor are connected respectively.

Preferably, the switching group includes the first power switch and the second power switch；First power switch and institute The second power switch is stated to be driven by the same driving unit, same drive signal, first power switch and The source electrode of second power switch is oppositely arranged；Or, first power switch and second power switch each via The independent driving unit, drive signal are driven, the source electrode of first power switch and second power switch It is disposed opposite to each other.

Preferably, first power switch and second power switch are managed for metal-oxide-semiconductor or IGBT.

Preferably, the amplitude range of the output voltage between the positive electrode bus and the negative electrode bus is up to that three-phase is mutually electric Press VIN √ 3* √ 2* (√ 3/2) times.

Preferably, input filter is further included, the input filter is arranged on the switch element front end, phase three-wire three Power supply accesses the switch element after input filter filters.

Meanwhile the utility model also proposed a kind of non-isolation type Three-phase PFC, including at least two as above any The pfc converter, 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 defects of the utility model overcomes traditional boost PFC circuit so that the DC converting of rear end Device does not have to be confined to the finiteness of power device, the utility model proposes voltage-dropping type pfc converter, also change conventional buck The way of realization of formula, has more simple topological structure, and driving electricity can be saved compared to 6-switch buck-type PFC Road (includes power supply), compared to Swiss rectifier in addition to it can save drive circuit (comprising power supply), can also save very much Power device, therefore whole ac-dc conversion circuit is simple, control logic is simplified, efficient, is suitable for high efficiency and high power Density requirement occasion, advantage are fairly obvious；

Functionally, the conducting for each circuitry phase which can be effectively ensured or inductive current work Make in continuous state, therefore there is preferable PF values and THDI, simultaneously as, symmetrical inductance (the first afterflow inductance of setting L1 and the second afterflow inductance L2), with reference to filter capacitor, be conducive to improve the EMI performances of the converter of non-isolation type or obtain compared with Good PF values and THDI.

From control, due to the simplification in structure, the reduction of power component, thereby reduces the difficulty of control, from PFC From the point of view of the switching manipulation of function, by one of switching group apply " height " driving condition PWM drive signal, to other two A switching group carries out the drive signal of PWM driving conditions, thus, can simplify control method.

So the utility model, in high power density occasion, advantage is fairly obvious, such as three-phase PFC of full stock mould block size, Meet high, refined, peak products needs.

Brief description of the drawings

Fig. 1 is existing boost type pfc circuit structure diagram.

Fig. 2 is existing SWiSS RECTIFER circuit diagrams.

Fig. 3 is existing 6-switch buck-type pfc circuit schematic diagrames.

Fig. 4 is the schematic diagram of the non-isolation type Three-phase PFC of the utility model embodiment 1.

Fig. 5 is that the three-phase voltage waveform signal of the utility model embodiment 1 and joint define schematic diagram.

Fig. 6 be the utility model embodiment 1 AC-BC sections AB to conducting circuit diagram.

Fig. 7 is the AC-BC interval B C phase continuous current circuit schematic diagrames of the utility model embodiment 1.

Fig. 8 is the AC-BC sections AC phase continuous current circuit schematic diagrames of the utility model embodiment 1.

Fig. 9 is the AC-BC sections inductive current continuous current circuit schematic diagram of the utility model embodiment 1.

Figure 10 is the negative side potential change schematic diagram of single afterflow inductance (positive side) circuit.

Figure 11 is the equivalent transformation schematic diagram of the utility model embodiment 1.

Figure 12 is the current potential equivalent transformation waveform diagram of the utility model embodiment 1.

Figure 13 is each switching group drive waveforms relation signal in the 1 three-phase alternating current cycle of the utility model embodiment.

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

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 non-isolation type Three-phase PFC, including switch element, rectification list Member, energy storage afterflow unit, the switch element include three switching groups, and three switching groups are separately positioned on the three-phase of access In three phase lines of three line power supplys；Three switching groups are connected by three phase lines with the rectification unit respectively；The storage Can afterflow unit include the first to the second afterflow inductance and filter capacitor, the positive terminal of the rectification unit by positive electrode bus and First afterflow inductance one end is connected, and negative pole end connected by negative electrode bus with second afterflow inductance one end, the positive electrode bus and Be equipped with the filter capacitor between negative electrode bus, the other end of the first afterflow inductance and the second afterflow inductance it is another The both ends respectively with the filter capacitor are held to be connected.

As shown in figure 4, from the three phase mains of input terminal input, including A phases, B phases and C phases, the voltage of three of them phase line is believed Number Fig. 5 is referred to, differ 120 degree of phase each other, there may be saltus step or polarity to dash forward due to the power supply signal that actually enters Become, so the voltage waveform shown in the present embodiment is for the ease of describing hereinafter, with the waveform of standard as reference.The present embodiment The converter shown further includes input filter, and the input filter is arranged on the switch element front end, phase three-wire three electricity The switch element is accessed in source after input filter filters, and in order to be greatly attenuated the EMI signal being passed to through power supply, protects equipment From its evil, as shown in figure 4, the present embodiment is electromagnetic interface filter in the input filter of phase three-wire three input terminal, EMI is set to filter Ripple device can also efficiently control the EMI signal that equipment produces in itself, prevent it from entering power grid, pollute electromagnetic environment, endanger other Equipment, in the present embodiment other alternative embodiments, can also be other kinds of wave filter.

The outlet side of electromagnetic interface filter is connected to switch element, and switch element is responsible for performing the switch behaviour of Active PFC Make, three switching groups of switch element are two-way switch, and each switching group includes the semiconductor power switch that two high frequencies are opened (the first power switch and the second power switch), as shown in figure 4, including including switching group in switching group Q1Q2, B phase in A phases Include switching group Q5Q6 in Q3Q4, C phase, which can manage for metal-oxide-semiconductor, IGBT, those skilled in the art It should be appreciated that the utility model is not limited to above two semiconductor power switch, other executable switch behaviour are can also be Work rate element.A, same driving power and same drive signal are not shared between the respective switching group of B, C phase；Together Two semiconductor power switch in one phase can share a driving power and same drive signal, can also be each independent Driving.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 driving can be shared Signal；When the source electrode of two metal-oxide-semiconductors is disposed opposite to each other, each can independently drive.Share a driving power and same drive Dynamic signal can make it that the structure of the present embodiment is simpler, it is not necessary to too many driving unit is set, for finite volume or The of a relatively high place of cost requirement, has direct advantage.

As shown in figure 4, 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 side of D5 and B Phase line is connected, the cathode side of the anode-side of D3 and D6 are connected with C phase lines, the cathode side of D1, D2, D3 for rectification unit just Pole side, it is connected with positive electrode bus BUS+, and the anode-side of D4, D5, D6 is the negative side of rectification unit, itself and negative electrode bus BUS- Connection.The cathode side of D1, D2, D3 are connected by positive electrode bus BUS+ with first afterflow inductance L1 one end, the anode of D4, D5, D6 Side is connected by negative electrode bus BUS+ with the second afterflow inductance L2 and second afterflow inductance L2 one end.

As shown in figure 4, the other end of the first afterflow inductance L1 is the cathode output end of converter, the second afterflow inductance L2's The other end is the cathode output end of converter, and load can be connect between cathode output end and cathode output end (or can be equivalent to load Circuit), the amplitude range of the output voltage of load-side is up to the √ 3* √ 2* (√ 3/2) of three-phase phase voltage VIN, and VIN is Phase voltage virtual value.Filter capacitor C1 is equipped between cathode output end and cathode output end, filter capacitor C1 can make direct current output Steadily, influence of the alternation pulse ripple to electronic circuit, while the electricity produced in the also absorbable electronic circuit course of work are reduced Stream fluctuation and the interference sealed in via AC power so that the working performance of electronic circuit is more stablized.

The present embodiment is because be the pfc converter of non-isolation type, if there was only unilateral inductance after rectification unit rectification Carry out afterflow (afterflow inductance is set only in positive electrode bus or negative electrode bus), in negative electrode bus (BUS-) or positive electrode bus (BUS+) There is no inductance, therefore the current potential of output terminal can turn on and off generation potential change, such as Figure 10 with input side switch element Shown only positive side is when having afterflow inductance, when being formed into a loop any two-phase in three-phase due to turning on and off for switch element, When outlet side has input current, then its current potential is consistent with the current potential of most negative input phase, when the switching group of wherein two-phase drives electricity Press for " 0 " state when, i.e., when not forming circuit, then its current potential is with being " 1 " the current potential of (or the intermediate magnitude phase) of state always Unanimously, thus the current potential without afterflow inductance side can be formed the change of high frequency pulse potential it is poor, the amplitude maximum of moment changes 1.5 times of Vp up to as shown in Figure 10, Vp are the peak-peak voltage of phase voltage, therefore to rear termination non-isolation type load Electromagnetic interference is larger, has a great influence to output electrical equipment, this will be limited in actual use.

So as shown in figure 4, two symmetrical first afterflow inductance L1 and the second afterflow inductance L2 are set, for improving The circuit structure of two symmetrical afterflow inductance, is carried out equivalent, equivalent circuit diagram such as figure by the EMI performances of non-isolation type converter Shown in 11, it can be seen from fig. 11 that being provided with two capacitance C/2 equivalent in outlet side, load and the two capacitances C/2 are simultaneously Connection, the midpoint of two capacitance C/2 is defined as equivalent midpoint, and due to the symmetry of rectification side, input side, which is led, to alive back Lu Shi, equivalent midpoint are then string ripple medians；After the switch element (maximum duty cycle) of input completely closes, outlet side is still It is full symmetric, therefore is considered as its relative potentials not having any change, is not in that being forced property is clamped to middle width The possibility of threshold voltage phase (or voltage phase of one state), solves the problems, such as that the pulse potential of high frequency change is poor, therefore to rear The electromagnetic interference for terminating non-isolation type load is smaller.Thus, the current potential of cathode output end (BUS-) by not with most negative input phase Current potential is consistent；Current potential between equivalent midpoint and cathode output end (BUS-) for the V- as shown in Figure 12, equivalent midpoint with just Current potential between pole output terminal (BUS+) is V+ as shown in Figure 12, the virtual ginseng of the current potential at equivalent midpoint as shown in Figure 12 The voltage of examination point；Filter capacitor C1 coordinates in symmetrically arranged two inductance (the first afterflow inductance of positive electrode bus and negative electrode bus L1 and the second afterflow inductance L2), reduction crosstalk can be played.

As shown in figure 5, 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 fig. 6, Q1Q2, Q3Q4 are turned on, electric current passes through switch element and D1, L1, L2, C1, D5 are formed into a loop.When the driving either driving closing of Q3Q4 of Q1Q2, then D3 or D6 can be turned on and continued by positive bias-voltage Galvanic electricity sense L1, L2 form freewheeling path, in order to ensure PF values, C phases can only with the voltage turn-on of opposite direction amplitude, therefore in the same direction That phase voltage of amplitude is first closed (such as then to be closed, such as Fig. 7, electricity in 30 ° -60 ° or AC-O sections, the driving of A phases prior to B Stream is formed into a loop by switch element and D3, L1, L2, C1, D5.60 ° -90 ° or O-BC sections, the driving of B phases are then related prior to A Close, such as Fig. 8, electric current is formed into a loop by switch element and D1, L1, L2, C1, D6.), the PWM drive patterns first closed are denoted as " small ", the PWM drive patterns turned off afterwards are denoted as " big ".

After the PWM driving voltages of AB two-phases are all closed, if C phase driving voltages still have, at this time, inductive current is then Afterflow can be carried out by D2+D5 or D1+D4, as shown in Figure 9；If C phases driving voltage is low level, inductive current can lead to Crossing D1+D4, either D2+D5 or D3+D6 carries 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 switch element, while turn-on consumption can also be reduced；Meanwhile in the segment, the electricity of each phase Stream can turn on, and be not in certain phenomenon that mutually stops in uncontrollable rectifier with arc in phase.Therefore as long as driving unit will PWM drive signal modulates, it is possible to so that current waveform follows unanimously with voltage waveform, therefore can obtain higher PF Value, that is, realize PFC correcting functions.

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, lock phase processor is carried out to the phase three-wire three power supply voltage signal of input, judge phase three-wire three electricity Phase and segment residing for the current time in source；It is absolute corresponding to voltage magnitude in the switch element under current interval section The switching group being worth on a minimum phase line, applying control, it is constantly in the first driving letter of conducting state in segment Number, and apply the second drive signal and the 3rd drive signal for carrying out PWM controls to the switching group on other two phase line so that Conducting circuit can be formed between phase three-wire three power supply, when input does not form conducting circuit, then passes through the of energy storage afterflow unit One to the second afterflow inductance carries out afterflow and discharges the former energy being stored in inductance.

It need not meet that afterflow inductive current is continuous always by the above method, per phase current in the complete period in the case of different loads Path will be formed by the combination of switch, thus need to confirm in the present embodiment in " high " state it is corresponding mutually with it is next Circuit can be formed between that one-phase circuit first opened, applies the second drive signal, the 3rd driving of PWM controls to other two-phase Signal.

The second drive signal, the 3rd drive signal of PWM controls are carried out, need to be further according to the zero crossing of three-phase voltage signal 6 original segments are divided into 12 segments, corresponding drive signal are performed according to this 12 segments by " O ".With Exemplified by ACO segments, first drive signal of " height " driving condition can perform for the switching group of C phases so that the phase line one Straight conducting；For the switching group on other two phase line, the inconsistent PWM drive signal of duty cycle each other will be accommodated, in this area Between in section, the PWM drive signal of B phases is the 3rd drive signal of " big " driving condition, and the PWM drive signal of A phases is " small " drive Second drive signal of dynamic state, as shown in figure 13, the 3rd drive signal duty cycle is more than the duty cycle of the second drive signal.It is logical Above-mentioned control method is crossed, the conducting for each circuitry phase that can be effectively ensured or inductive current work in continuous state, are realized with this High PF and low THDI；

As shown in figure 13, the sequence diagram under 12 different sections is summarized, accounting for for driving is adjusted to different segments Empty ratio, i.e.,：

When the voltage magnitude absolute value of phase where switch element is minimum in three-phase, which is accommodated in the area Between the first always on drive signal is kept in section；Meanwhile progress is applied respectively to the switch element in other two-phase The second drive signal and the 3rd drive signal of PWM controls；In the segment, in other two phase line, voltage side Apply second drive signal to the switching group on a phase line identical with that phase line of voltage magnitude absolute value minimum, The different switching group of voltage direction applies the 3rd drive signal, and the duty cycle of second drive signal is less than the described 3rd The duty cycle of drive signal.

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

If three switching groups that some time inscribes switch element are both turned on, where two switching groups for carrying out PWM controls It is formed into a loop between two phase lines by rectification unit, the first to the second afterflow inductance；

During subsequent time, by opening on a voltage direction phase line identical with the phase line of voltage magnitude absolute value minimum Pass group is closed, and the different switching group of voltage direction maintains conducting so that maintains a phase of conducting and voltage magnitude absolute value minimum A phase between pass through rectification unit, the first to the second afterflow inductance be formed into a loop, complete afterflow；

Next moment is gone successively to, the two-phase for carrying out PWM controls is turned off, is not formed into a loop in three-phase, by whole Flow unit and symmetrically arranged first afterflow inductance and the second afterflow inductance carries out afterflow；

Subsequent time, the switching group of a phase line identical with a phase voltage direction of voltage magnitude absolute value minimum is protected Hold closing, the switching group in the different phase of voltage direction turns on again, and the phase line and voltage magnitude turned on again is absolute It is formed into a loop between one phase line of value minimum, completes afterflow.

Subsequent time is entered back into, by opening for a phase line identical with a phase voltage direction of voltage magnitude absolute value minimum Pass group 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, and carries out the two of PWM controls It is formed into a loop between two phase lines where a switching group, thus circulates.

Corresponding A CO segments, when this starts, A phases and B are conducted, forming circuit, immediately, due to A phase drive signal duties Than small, A phases are first closed, and B phases are turned on C, and then, both are turned off, into inductance freewheeling state, since B phase drive signals account for Sky is than big, and subsequent B phases are first opened, and B phases are turned on C, and forming circuit, subsequent A phases and B phases are opened, and A phases and B are conducted, so Circulation, until ACO segments terminate, into after next segment, according to the characteristics of OBC segments, changes duty cycle.

First drive signal is PWM drive signal, its driving voltage is more than second drive signal and the 3rd and drives The driving voltage of dynamic signal；It is high level always to be on " height " driving condition, or the duty cycle master with " big " state consistency To depend on output loading, its otherness is influence of the relative fluctuation to load of output voltage, the present embodiment right and wrong every Release circuit, if output connects non-isolation type load, preferred " high " state can only be the drive signal with " big " state consistency. If output loads for isolated form, " high " state both of which drive signal, but is preferably and " big " state consistency Drive signal.

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 input electricity Stream is continuous, and improves EMI.

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

A kind of 1. non-isolation type Three-phase PFC, it is characterised in that：Including switch element, rectification unit and energy storage afterflow list Member, the switch element include three switching groups, and three switching groups are separately positioned on the three of the phase three-wire three power supply of access In root phase line；Three switching groups are connected by three phase lines with the rectification unit respectively；The energy storage afterflow unit bag The the first to the second afterflow inductance and filter capacitor are included, the positive terminal of the rectification unit passes through positive electrode bus and the first afterflow inductance One end is connected, and negative pole end is connected by negative electrode bus with second afterflow inductance one end, between the positive electrode bus and negative electrode bus Equipped with the filter capacitor, the other end of the other end of the first afterflow inductance and the second afterflow inductance respectively with it is described The both ends connection of filter capacitor.
2. Three-phase PFC as claimed in claim 1, it is characterised in that：The switching group include the first power switch and Second power switch；First power switch and second power switch are believed by same driving unit, same driving Number it is driven.
3. Three-phase PFC as claimed in claim 2, it is characterised in that：First power switch and second work( The source electrode of rate switch is oppositely arranged.
4. Three-phase PFC as claimed in claim 1, it is characterised in that：The switching group include the first power switch and Second power switch；First power switch and second power switch are believed each via independent driving unit, driving Number it is driven.
5. Three-phase PFC as claimed in claim 4, it is characterised in that：First power switch and second work( The source electrode of rate switch is disposed opposite to each other.
6. the Three-phase PFC as described in claim 2 or 4, it is characterised in that first power switch and described second Power switch is managed for metal-oxide-semiconductor or IGBT.
7. Three-phase PFC as claimed in claim 1, it is characterised in that：Between the positive electrode bus and the negative electrode bus Output voltage amplitude range be up to three-phase phase voltage VIN √ 3* √ 2* (√ 3/2) times.
8. Three-phase PFC as claimed in claim 1, it is characterised in that：Further include input filter, the input filter Device is arranged on the switch element front end, and phase three-wire three power supply accesses the switch element after input filter filters.
A kind of 9. non-isolation type Three-phase PFC, it is characterised in that：Including at least two as described in claim 1-8 is any Pfc converter, connected with parallel or crisscross parallel between each pfc converter.