CN107800309A - A kind of single-stage isolated type Three-phase PFC and its control method - Google Patents

A kind of single-stage isolated type Three-phase PFC and its control method Download PDF

Info

Publication number
CN107800309A
CN107800309A CN201710970362.7A CN201710970362A CN107800309A CN 107800309 A CN107800309 A CN 107800309A CN 201710970362 A CN201710970362 A CN 201710970362A CN 107800309 A CN107800309 A CN 107800309A
Authority
CN
China
Prior art keywords
phase
drive signal
unit
switch
pfc
Prior art date
Application number
CN201710970362.7A
Other languages
Chinese (zh)
Inventor
李伦全
周涛
郑车晓
Original Assignee
深圳市保益新能电气有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 深圳市保益新能电气有限公司 filed Critical 深圳市保益新能电气有限公司
Priority to CN201710970362.7A priority Critical patent/CN107800309A/en
Publication of CN107800309A publication Critical patent/CN107800309A/en

Links

Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00Details of apparatus for conversion
    • H02M1/32Means for protecting converters other than automatic disconnection
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00Details of apparatus for conversion
    • H02M1/42Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208Arrangements for improving power factor of AC input
    • H02M1/4216Arrangements for improving power factor of AC input operating from a three-phase input voltage
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/22Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion
    • Y02B70/12Power factor correction technologies for power supplies
    • Y02B70/126Active technologies
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion
    • Y02B70/14Reduction of losses in power supplies
    • Y02B70/1491Other technologies for reduction of losses, e.g. non-dissipative snubbers, diode reverse recovery losses minimisation, zero voltage switching [ZVS], zero current switching [ZCS] or soft switching converters

Abstract

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

Description

A kind of single-stage isolated type Three-phase PFC and its control method

Technical field

The present invention relates to electric and electronic technical field, more particularly to a kind of single-stage isolated type Three-phase PFC and its Control method.

Background technology

It is to use three phase supply mostly because 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 quality of power supply of power network will be destroyed it is very big, or even it is serious when can cause The paralysis of power network, 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 certain limit, Following stage is required to increase one-level 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 also have 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 network, surging, frequency The various actual conditions such as saltus step.Because the circuit is overly simplified, conducting can only be a phase switches set every time, and three-phase is successively Samsara, directly loop is formed with the resonant capacitance being respectively connected by resonant inductance, transformer after opening;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, and 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 easily causes the damage of switches set, therefore it is detected protection and requires high, corresponds to not Same grid condition needs to set different protections and mode of operation, and control algolithm certainly will be become into 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 network 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 scheme that auxiliary understands the present invention, and it is not The prior art of present patent application is necessarily belonged to, shows the applying date of the above in present patent application in no tangible proof In the case of disclosed, above-mentioned background technology should not be taken to evaluate the novelty and creativeness of the application.

The content of the invention

It is above-mentioned to solve present invention aims at a kind of single-stage isolated type Three-phase PFC of proposition and its control method The limited technical problem of application caused by structure existing for prior art and control method are complicated.

Therefore, the present invention proposes a kind of single-stage isolated type Three-phase PFC, including primary side input circuit, transformer With secondary output circuit, the primary side input circuit includes first switch unit, the first rectification unit, second switch unit, string Join resonant element;The first switch unit includes three switches sets, and three switches sets are separately positioned on the three-phase of access In three phase lines of three line power supplys;Three switches sets are connected by three phase lines with first rectification unit respectively;Institute State the first rectification unit and connect the second switch unit and the series resonance unit concatenated with one another, the one of the transformer Secondary side, the secondary side of the transformer are connected with secondary output circuit;First rectification unit performs AC rectification operation, institute State transformer to perform isolation and become press operation, the switches set had both been used to perform AC power factor correction switching manipulation, again matched somebody with somebody Close the series resonance unit, the transformer and perform the second switch unit of reverse resonance channel selector operation together Complete the function of series resonance translation circuit.

Preferably, the switches set 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 same drive signal;Or, first power switch and second power are opened Pass is driven each via independent drive signal.

Preferably, the secondary output circuit includes the second rectification unit, second rectification unit can be voltage multiplying rectifier, Full-wave rectification or full-bridge rectification.

Preferably, the secondary output circuit also includes energy storage afterflow unit, and the energy storage afterflow unit is not provided with afterflow Inductance, sets filter capacitor, and the filter capacitor and second rectification unit simultaneously connect;Or the energy storage afterflow unit set to A few afterflow inductance and at least one filter capacitor, at least one afterflow inductance concatenated with one another with it is at least one described Filter capacitor is connected with second rectification unit.

Preferably, first power switch, second power switch and the second switch unit be metal-oxide-semiconductor or IGBT is managed.

Preferably, the series resonance unit includes at least one resonant inductance and at least one resonant capacitance, described humorous The inductance that shakes is connected in series with the resonant capacitance.

Preferably, the primary side input circuit also includes input filter, and the input filter is arranged on described first Switch element front end, phase three-wire three power supply access the first switch unit after input filter filters.

Meanwhile the invention also provides another single-stage isolated type Three-phase PFC, including at least two as above any Described pfc converter, connected with parallel or crisscross parallel between each pfc converter.

In addition, the invention also provides a kind of control method for above-mentioned single-stage isolated type Three-phase PFC, bag Include following steps:

Input/output condition is detected, judges whether input/output condition meets condition of work, the condition of being unsatisfactory for continues waiting for; If meeting condition, start working, 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;

To in the first switch unit under current interval section, corresponding on the minimum phase line of voltage magnitude absolute value Switches set, applying control, it is constantly in the first drive signal of conducting state in segment, and on other two phase line Switches set apply carry out PWM controls the second drive signal and the 3rd drive signal, and to second switch unit carry out PWM The fourth drive signal of control so that conducting loop can be formed between phase three-wire three power supply, and when not forming conducting loop, is led to Cross second switch unit and realize afterflow and reverse resonance.

Preferably, the first drive signal of application is:Existing high level signal always;Or PWM drive signal, it is described The driving voltage of PWM drive signal is more than the driving voltage of the second drive signal and the 3rd drive signal.

In the segment, in other two phase line, voltage direction that phase minimum with voltage magnitude absolute value Switches set on the phase line of circuit identical one applies second drive signal, described in the different switches set of voltage direction applies 3rd drive signal, the dutycycle of second drive signal are less than the dutycycle of the 3rd drive signal, and the described 4th The dutycycle of drive signal is identical with the dutycycle of the 3rd drive signal.

The dutycycle of 3rd drive signal is not more than 0.5, and the 3rd drive signal dutycycle is believed with the 4th driving Number dutycycle form complementation.

Finally, the present invention proposes a kind of control method for above-mentioned single-stage isolated type Three-phase PFC, passes through Any of the above-described described control method is controlled to the Three-phase PFC that at least two are connected in parallel respectively, wherein, at least The operating phase of two Three-phase PFCs being connected in parallel differs half of high frequency period.

The beneficial effect that the present invention is compared with the prior art includes:

From structure, the present invention changes the implementation method that traditional pfc circuit adds DC-isolation translation circuit, passes through this The topological structure of invention, the energy-storage units that can be saved after the AC rectification of conventional AC/DC convertor, while can also save straight The power device and drive circuit of isolated variable are flowed, whole ac-dc conversion circuit is simple, and control logic is simplified, efficiency high, It is suitable for high efficiency and high power density demand occasion;Functionally, relative to traditional with Active PFC function For isolated form three-phase AC/DC conversion device, AC-DC conversion function, power factor (PF) school are achieved that by primary conversion circuit Orthofunction, isolated variable, Sofe Switch and voltage regulation function, can save many power rate devices, while compared to being previously mentioned Cycloconverter, because the input of phase three-wire three power supply can form loop between the two phases, every time conducting be no longer One phase switches set, the situation that saltus step or polarity mutation occurs in input voltage can be successfully managed, its grid adaptability is stronger, work Stability is higher, and equipment quality is relatively reliable.

Brief description of the drawings

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

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

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

Fig. 4 be the embodiment of the present invention 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 embodiment of the present invention 1.

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

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

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

Fig. 9 is the equivalent transformation signal 1 of the embodiment of the present invention 1.

Figure 10 is the equivalent transformation signal 2 of the embodiment of the present invention 1.

Figure 11 is the equivalent transformation signal 3 of the embodiment of the present invention 1.

Figure 12 is the equivalent transformation signal 4 of the embodiment of the present invention 1.

Figure 13 is the timing diagram of each drive signal under 12 segments in the embodiment of the present invention 1.

The structural representation of the variant embodiment 2 of Figure 14 embodiment of the present invention 1.

Figure 15 is the structural representation of the variant embodiment 3 of the embodiment of the present invention 1.

Figure 16 is that the secondary output circuit of the embodiment of the present invention 1 does not have the structural representation of afterflow inductance.

Embodiment

With reference to embodiment and compare accompanying drawing the present invention is described in further detail.It is emphasized that What the description below was merely exemplary, the scope being not intended to be limiting of the invention and its application.

With reference to the following drawings, non-limiting and nonexcludability embodiment will be described, wherein identical reference represents Identical part, 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 switches sets, and three switches sets are separately positioned on access In three phase lines of phase three-wire three power supply;Three switches sets 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 switches set is both used to perform AC power factor correction switch behaviour Make, coordinate the series resonance unit, the transformer and the second switch for performing reverse resonance channel selector operation again 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 its three phase lines refers to figure 3,120 degree of phase is differed each other, because the power supply signal actually entered there may be saltus step or polarity mutation, so The voltage waveform for implementing to exemplify is used as reference for the ease of describing hereinafter, using the waveform of standard.Primary side input circuit also includes Input filter, the input filter are arranged on first switch unit front end, and phase three-wire three power supply filters through input filter First switch unit is accessed afterwards, and in order to be greatly attenuated the EMI signal being passed to through power supply, protection equipment does harm to from it, such as Fig. 2 institutes Show, the present embodiment is electromagnetic interface filter in the input filter of phase three-wire three input, sets electromagnetic interface filter also can effectively control Control equipment caused EMI signal in itself, prevent it from entering power network, pollute 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 switches sets 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 switches set Q5Q6 in switches set Q3Q4, C phase in switches set Q1Q2, B phase, the semiconductor power switch can be with Managed for metal-oxide-semiconductor, IGBT, it should be appreciated by those skilled in the art to the present invention is not limited to above two semiconductor power and opened Close, can also be the power component of other executable switching manipulations.A, do not shared between the respective switches set of B, C phase same Driving power and same drive signal;Two semiconductor power switch in same phase can share a driving power and same One drive signal, each can also independently it drive., can be with when the source electrode of two metal-oxide-semiconductors is oppositely arranged by taking metal-oxide-semiconductor as an example Share a driving power and same drive signal;When the source electrode of two metal-oxide-semiconductors is disposed opposite to each other, each can independently drive It is dynamic.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 More driver elements, for the of a relatively high place of finite volume or cost requirement, there is 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, diode D1 anode-side and D4 cathode side are connected with A phase lines, D2 anode-side and D5 negative electrode Side is connected with B phase lines, D3 anode-side and D6 cathode side 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, second switch unit Q7 source side and diode D4, D5 and D6 Anode-side connects, and second switch unit Q7 drain side is connected with diode D1, D2, D3 cathode side;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 invention is not limited in above two semiconductor power switch, can also be the power member of other executable switching manipulations Part.Meanwhile in the present embodiment, as shown in figure 4, the diode of the first rectification unit and first switch unit etc. is parasitic in parallel electric It is that Cp shows in circuit to hold parameter equivalent, it is preferred that when the Cp is less, can also optionally it increase, so as to 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 transformer Tra two level side, is a typical full bridge rectifier, just 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 Electric capacity 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 loop of B phases simultaneously, D5 is turned on by positive bias-voltage, and C phases D3 And D6 can not 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 form loop.When Q1Q2 driving or Q3Q4 driving are closed, 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 forms 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 forms loop by first switch unit and D1, Lr, Tra, Cr, D6.), the PWM first closed drives We are designated as " small " to dynamic model formula, and the PWM drive patterns turned off afterwards are designated as " big ".

After the PWM driving voltages of AB two-phases are all closed, therefore inputting three-phase alternating current does not have any loop to turn on, now before Electric current meeting nature afterflow in the loop of phase conducting, wherein Cp energy moment completes release, if C phase driving voltages are still deposited Now, as shown in fig. 7, electric current can then be entered by D2+D5+Q7 (anti-and diode) or D1+D4+Q7 (anti-and diode) Row afterflow;If C phases driving voltage is low level, inductive current can then 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 (high level) be present always, or more than or equal to other two Maximum PWM driving voltage in phase, such a driving condition can be abbreviated as " height ", i.e., now only need the drivings of AB two-phases according to Control needs to send out the step-down rectifier that corresponding high-frequency PWM drive signal can realizes 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 driver element 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, now apply high level drive signal to Q7, 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 entered 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 of input forms loop.

Each mode of operation 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.Because Cp is foregoing each switching tube and diode parasitic capacitance, therefore can be with 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 summary, the whole work for inputting 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 Q7 shut-off is Sofe Switch or close to Sofe Switch, then should try one's best makes the of input One switch element dutycycle is no more than 50%, and is approached with Q7 dutycycle.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 regulating frequency, when input voltage exceedes certain limit 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 dutycycle 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, 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 dutycycle 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 present invention is not only defeated in preferable three-phase alternating current Energy normal work under the conditions of entering, because three switches sets of first switch unit can meet under any three-phase alternating current input condition, When the three-phase alternating-current supply of input will can pass through resonant inductance Lr, transformer, Cr formation loops, two-phase switches set has at least been needed to open Open, so in the case where saltus step or polarity mutation occurs in input voltage, it is not easy to form reverse spike voltage and electric current falls Fill, small is required 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 present invention changes the implementation method that traditional pfc circuit adds DC-isolation translation circuit, By the topological structure of the present invention, the energy-storage units that can be saved after the AC rectification of conventional AC/DC convertor, while also may be used The power device and drive circuit of DC-isolation conversion are saved, whole ac-dc conversion circuit is simple, and control logic is simplified, effect Rate is high, 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 form loop between the two phases, and conducting is no longer a phase switches set every time, can successfully manage input There is the situation of saltus step or polarity mutation in voltage, and its grid adaptability is stronger, and job stability is higher, and 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 switches set, PWM is carried out to other two switches sets 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, change 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 dutycycle is recycled to be adjusted, to ensure that maximum Sofe Switch works.

For other segments, by that analogy, 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 then closes 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 then close prior to C, and O-CA sections, the driving of C phases then closes 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 then close prior to B, and O-CB sections, the driving of B phases then closes 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 then close prior to A, and O-AB sections, the driving of A phases then closes 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 then close prior to C, and O-AC sections, the driving of C phases then closes prior to B.

Because three-phase voltage might not be completely preferable in reality, the change of phase, amplitude, direction be present, can only basis 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, and other two PWM drive signals are the second drive signal and the 3rd driving letter Number, it is the drive signal waveform logical table of Q1Q2, Q3Q4, Q5Q6 in a cycle in summary.

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 condition of work, the condition of being unsatisfactory for continues waiting for; If meeting condition, start working, 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 Switches set on the minimum phase line of amplitude absolute value, 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 switches set 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 Loop, and when not forming conducting loop, 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 Zero crossing " O ", 6 original segments are divided into 12 segments, duty ratio corresponding is performed according to this 12 segments 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 switches set of C phases Dynamic signal so that the phase line is constantly on;For the switches set on other two phase line, it is inconsistent that dutycycle 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 dutycycle is more than second The dutycycle of drive signal, it can realize that the switches set of A phases is first closed, be closed after the switches set 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 loops is switched to, avoids uniline from accessing, improves power network adaptive faculty, and forms afterflow, realizes PFC functions;Meanwhile It can realize and be turned off in A phases and B phases, after the switches set of A phases and B phases is turned off, although the switches set of C phases keeps open-minded, But the three-phase alternating-current supply of input can not be made to form loop, now, with " big " driving condition, i.e., second switch unit is applied The complementary fourth drive signal with the 3rd drive signal, when the three-phase alternating-current supply of input can not be made to form loop, 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 switches set and second switch unit the first drive signal, the second drive signal, the 3rd drive signal and Under the control of fourth drive signal, switching manipulation corresponding to realization.As shown in figure 13, the sequential under 12 different sections is summarized Figure, the dutycycle driven to different segment regulation regulations, i.e.,:

In the segment, in other two phase line, voltage direction that phase minimum with voltage magnitude absolute value Switches set on the phase line of circuit identical one applies second drive signal, described in the different switches set of voltage direction applies 3rd drive signal, the dutycycle of second drive signal are less than the dutycycle of the 3rd drive signal, and the described 4th The dutycycle of drive signal is identical with the dutycycle of the 3rd drive signal.

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

If three switches sets that some time inscribes first switch unit are both turned on, then second switch unit can not turn on, this Pass through rectification unit, series resonance unit, transformation between two phase lines where two switches sets that PWM described in Shi Jinhang is controlled The primary side of device forms loop;

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 switches set on the phase line of phase line identical one minimum with voltage magnitude absolute value, the different switch of voltage direction Group maintains conducting so that maintains between a phase line of conducting and the phase line that voltage magnitude absolute value is minimum by rectification list Member, the primary side of series resonance unit, transformer form loop;

Go successively to next moment, second switch unit, series resonance unit, transformer primary side afterflow after control The second switch unit conducting, the switches set that last moment maintains conducting is closed, the switches set for now carrying out PWM controls is equal Close, loop is formed by the primary side of second switch unit, series resonance unit, transformer.

Subsequent time, second switch unit is closed, by a phase voltage direction identical minimum with voltage magnitude absolute value The switches set of one phase line remains turned-off, and voltage direction difference switches set turns on again, the phase line and voltage turned on again Loop is formed between the minimum phase line of amplitude absolute value.

Subsequent time is entered back into, closes second switch unit, by a phase voltage direction minimum with voltage magnitude absolute value The switches set of the phase line of identical one is opened, and voltage direction difference switches set is kept it turned on, and now, the switches set on three-phase is opened Open, form loop between two phase lines where two switches sets of progress PWM controls, thus circulate.

Corresponding A CO segments, when just starting, Q7 is closed, and A phases and B are conducted, and forms loop;Immediately, because A phases drive Signal dutyfactor is small, and A phases are first closed, and B phases are conducted with C, and now Q7 continues to close;Then, both are turned off, into afterflow shape State, Q7 is opened after afterflow;Because B phase drive signal dutycycles are big, subsequent B phases are first opened, and B phases are conducted with C, form loop, Now Q7 is closed;Subsequent A phases and B phases are opened, and A phases and B are conducted, and now Q7 continues to close;So circulation, until ACO areas Between section terminate, into after next segment, according to the characteristics of OBC segments, change dutycycle.

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 on output loading with the dutycycle of " big " state consistency, and 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 the PWM drive signal with " 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 controlled to the Three-phase PFC that at least two are connected in parallel respectively, and the present embodiment can be equivalent to series resonant full bridge, Converter A and converter B half of high frequency period of operating phase misphase, while Q7A and Q7B is respectively 50% dutycycle, so A roads First switch unit (Q1AQ2A, Q3AQ4A, Q5AQ6A) conducting when pass through Q7B formed loop, B roads first switch unit Loop is formed by Q7A when (Q1BQ2B, Q3BQ4B, Q5BQ6B) is turned on.

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 present invention, it will be apparent to those skilled in the art that It can be variously modified and replaced, without departing from the spirit of the present invention.Furthermore it is possible to many modifications are made with by spy Condition of pledging love is fitted to the religious doctrine of the present invention, without departing from invention described herein central concept.So the present invention is unrestricted In specific embodiment disclosed here, but the present invention all embodiments that may also include belonging to the scope of the invention and its equivalent Thing.

Claims (13)

  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 switches sets, and three switches sets are separately positioned on the phase three-wire three power supply of access Three phase lines on;Three switches sets 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 switches set include the first power switch and Second power switch;First power switch and second power switch are driven by same drive signal;Or, First power switch and second power switch are driven each via independent drive signal.
  3. 3. 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.
  4. 4. Three-phase PFC as claimed in claim 3, it is characterised in that:The secondary output circuit also continues including energy storage 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.
  5. 5. Three-phase PFC as claimed in claim 2, it is characterised in that:First power switch, second power Switch and the second switch unit are that metal-oxide-semiconductor or IGBT are managed.
  6. 6. 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.
  7. 7. Three-phase PFC as claimed in claim 1, it is characterised in that:The primary side input circuit also 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.
  8. A kind of 8. single-stage isolated type Three-phase PFC, it is characterised in that:Including at least two such as any institutes of claim 1-7 The pfc converter stated, connected with parallel or crisscross parallel between each pfc converter.
  9. 9. a kind of control method for any described single-stage isolated type Three-phase PFCs of claim 1-7, its feature exists In comprising the following steps:
    Input/output condition is detected, judges whether input/output condition meets condition of work, the condition of being unsatisfactory for continues waiting for;If Meet condition, start working, lock phase processor is carried out to the phase three-wire three power supply voltage signal of input, judges phase three-wire three power supply Phase and segment residing for current time;
    To in the first switch unit under current interval section, corresponding to the switch on the minimum phase line of voltage magnitude absolute value Group, applying control, it is constantly in the first drive signal of conducting state in segment, and to opening on other two phase line Pass group applies the second drive signal and the 3rd drive signal for carrying out PWM controls, and carries out PWM controls to second switch unit Fourth drive signal so that conducting loop can be formed between phase three-wire three power supply, and when not forming conducting loop, by the Two switch elements realize afterflow and reverse resonance.
  10. 10. Three-phase PFC control method as claimed in claim 9, it is characterised in that:The first drive signal applied For:Existing high level signal always;Or PWM drive signal, the driving voltage of the PWM drive signal are more than described second and driven The driving voltage of dynamic signal and the 3rd drive signal.
  11. 11. Three-phase PFC control method as claimed in claim 9, it is characterised in that:It is described in the segment In other two phase line, the switches set on voltage direction that phase line of phase line identical one minimum with voltage magnitude absolute value Apply second drive signal, the different switches set of voltage direction applies the 3rd drive signal, the second driving letter Number dutycycle be less than the 3rd drive signal dutycycle, and the dutycycle of the fourth drive signal with the described 3rd drive The dutycycle of dynamic signal is identical.
  12. 12. the Three-phase PFC control method as described in claim 9-11 is any, it is characterised in that:3rd driving The dutycycle of signal is not more than 0.5, and the dutycycle of the 3rd drive signal dutycycle and fourth drive signal forms complementation.
  13. 13. the control method of a kind of single-stage isolated type Three-phase PFC for described in claim 8, it is characterised in that logical Any described control methods of claim 9-12 are crossed respectively to control the Three-phase PFC that at least two are connected in parallel System, the operating phase of at least two Three-phase PFCs being connected in parallel differ half of high frequency period.
CN201710970362.7A 2017-10-16 2017-10-16 A kind of single-stage isolated type Three-phase PFC and its control method CN107800309A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201710970362.7A CN107800309A (en) 2017-10-16 2017-10-16 A kind of single-stage isolated type Three-phase PFC and its control method

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201710970362.7A CN107800309A (en) 2017-10-16 2017-10-16 A kind of single-stage isolated type Three-phase PFC and its control method
PCT/CN2017/112382 WO2019075837A1 (en) 2017-10-16 2017-11-22 Single-stage isolated three-phase pfc converter and control method therefor

Publications (1)

Publication Number Publication Date
CN107800309A true CN107800309A (en) 2018-03-13

Family

ID=61533300

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201710970362.7A CN107800309A (en) 2017-10-16 2017-10-16 A kind of single-stage isolated type Three-phase PFC and its control method

Country Status (2)

Country Link
CN (1) CN107800309A (en)
WO (1) WO2019075837A1 (en)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1140045C (en) * 2000-11-09 2004-02-25 台达电子工业股份有限公司 Quasi-single-stage power converter with power factor correction
CN100377481C (en) * 2003-03-24 2008-03-26 台达电子工业股份有限公司 Integration converton with three phase power factor correction
CN201194372Y (en) * 2008-04-18 2009-02-11 艾默生网络能源有限公司 Three-phase input non-isolation type converter
US8004119B2 (en) * 2008-07-07 2011-08-23 The Hong Kong Polytechnic University Multi-function three-phase active power filter
US8687388B2 (en) * 2012-01-31 2014-04-01 Delta Electronics, Inc. Three-phase soft-switched PFC rectifiers
CN103378600A (en) * 2012-04-24 2013-10-30 张佩佩 Three-phase power factor correcting circuit and power factor improving method thereof
CN105576813B (en) * 2014-10-17 2019-06-04 维谛技术有限公司 A kind of the battery group mounting circuit and uninterruptible power supply of uninterruptible power supply

Also Published As

Publication number Publication date
WO2019075837A1 (en) 2019-04-25

Similar Documents

Publication Publication Date Title
Zygmanowski et al. Capacitance and inductance selection of the modular multilevel converter
US7333349B2 (en) Single-stage buck-boost inverter
Enjeti et al. Optimal power control strategies for neutral point clamped (NPC) inverter topology
CN100521506C (en) Multi-level frequency conversion driving apparatus with energy conservation unit
Qiao et al. A general three-phase PFC controller for rectifiers with a series-connected dual-boost topology
WO2003063331A1 (en) An apparatus and a method for voltage conversion
US10411613B2 (en) Inductive power transfer control
Liserre et al. An overview of three-phase voltage source active rectifiers interfacing the utility
CN101197547B (en) Three-phase synchronization AC generating circuit and its control method
WO2003107522A1 (en) Impedance source power converter
CN101958657A (en) Power supply switching circuit, equipment and alternate control method of power factor correction circuit
WO1998016993A1 (en) Converter
Zhao et al. Switched Z-source isolated bidirectional DC–DC converter and its phase-shifting shoot-through bivariate coordinated control strategy
CN102624266A (en) Three-level inverter circuit
AU2012254901B2 (en) Inverter topology circuit, inversion method and inverter
CN103683356B (en) On-Line UPS topology
US5946208A (en) Power converter
CN1599233A (en) Variable frequency driving device of 3KV-10KV middle-high voltage multi-level three-phase AC motor
Lin et al. Single-phase three-level PWM rectifier
US9219423B2 (en) Converter bridge arm suitable for high-voltage applications and application system thereof
CN103248252A (en) Modulation strategy for modular multilevel transducer
US20070223258A1 (en) Multilevel converters for intelligent high-voltage transformers
CN103001573B (en) Medium voltage converter drive system
Divan et al. Thin AC converters—A new approach for making existing grid assets smart and controllable
CN102255542A (en) Single-stage boosting inverter with tap inductor

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination