CN101931333A - The power converter that adopts changeable switch frequency and have the magnetic device in non-homogeneous gap - Google Patents
The power converter that adopts changeable switch frequency and have the magnetic device in non-homogeneous gap Download PDFInfo
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Abstract
The present invention relates to a kind of power converter that adopts changeable switch frequency and have the magnetic device in non-homogeneous gap.A kind of power converter is provided, and it comprises power switch, be used to the magnetic device controlling the controller of its switching frequency and have non-homogeneous gap.In one embodiment, this power converter comprises power switch and is coupled to this power switch and has the magnetic device in non-homogeneous gap.This power converter comprises that also having configuration is used for the controller that sensing is represented the status detection device of this power converter power output.The configuration of the control circuit of this controller is used for controlling according to described state the switching frequency of this power switch, and the duty ratio of controlling this power switch is to adjust the output characteristic of this power converter.
Description
Technical field
Relate generally to power electronic device of the present invention, and the power converter that relates more specifically to comprise power switch, is used to control the controller of its switching frequency and has the magnetic device in non-homogeneous gap.
Background technology
The power converter of switching mode (being also referred to as " power converter " or " adjuster ") is power supply or the Power Processing circuit that input voltage waveform is converted to specific output voltage waveforms.The DC-DC power converter is converted to direct current (dc) output voltage with direct current (dc) input voltage.The controller that is associated with power converter is managed its operation by the turn-on cycle of controlling use therein power switch.Usually, controller is coupling between the input and output of this power converter with feedback loop configuration (being also referred to as " control loop " or " closed control loop ").
Usually, controller is measured the output characteristic (as the combination of output voltage, output current or output voltage and output current) of this power converter, revises the duty ratio of the power switch of power converter then based on this.Duty ratio " D " is the turn-on cycle of power switch and the ratio of its switching cycle.Therefore, if power switch half switching cycle conducting, then the duty ratio of this power switch just is 0.5 (or 50%).In addition, along with system dynamically changes (changing as the calculated load on the microprocessor) as voltage or electric current by the microprocessor of power converter energy supply, controller will be configured to dynamically improve or reduce the wherein duty ratio of power switch, output characteristic such as output voltage are remained on the value of hope.
Be designed for the power converter of under lower power levels, operating and adopt feedback power chain topological structure usually, to realize lower manufacturing cost.Be designed for the VD that AC supply voltage is transformed into after the adjusting and think that the power converter with low rated power of electronic load such as printer, modulator-demodulator or personal computer energy supply usually is called " power adapters " or " AC adapter ".Some power adapters can be required the peak power in short-term that provides more much higher than nominal operation power level.Power adapters with 25 watts of nominals output rated power can be required to produce in operation cycle in load is relatively than small fragment the maximum output up to 60 watts, for example for 40 milliseconds (ms) in 240 milliseconds of operation cycles of load.
In the certain power link topological structure that is adopted in power converter, the peak operation electric current in magnetic device such as the power transformer (being also referred to as transformer) in the part winding elementary with it of magnetic flux is proportional.Correspondingly, the magnetic device in the power adapters can designed to be used peak power, rather than nominal output rated power.Yet excessive magnetic device will increase its cost, and this market to market in enormous quantities such as printer, modulator-demodulator and personal computer is unusual important consideration.The power converter that is designed for peak power also can be increased in the power loss under the lower power levels, under the higher output power level, entered DCM (DCM) because power converter typically is designed to, rather than be designed to only under nominal power output level, operate.
The power conversion efficiency of power adapters has become important market standard, particularly because the issue of the star standard of american energy recently, its power conversion efficiency that requires the personal computer power adapters should be at least 50% being lower than under 1 watt the power output level." 1 watt of proposal " of International Energy Agency is another energy saving activity, is reduced to 1 watt or still less with the standby power with equipment.These require to be to be based upon in the efficient under the very low power output level on the angle of typical load of the printer representative that is under free time or the park mode, this be under family expenses or the working environment these equipment at the mode of operation of most of the time.Power adapters designer's challenge is that high-caliber power conversion efficiency is provided in wide output power range.
Develop a lot of strategies and reduced manufacturing cost, and the power conversion efficiency of increase power adapters in wide power output horizontal extent, these strategies are included in and adopt the pulse operation pattern under the very low power output level, add energy and recover buffer circuit or customization integrated manipulator, and adopt well-designed application specific architecture.Yet each in these methods all provides cost or efficiency limitations, among others, and it often can not treat the particular customer demand in the market with a certain discrimination.Correspondingly, prior art needs a kind of method for designing of power adapters, and it can make manufacturing cost further reduce and improve power conversion efficiency and can not sacrifice the final products performance, and is applicable to manufacturing technology in enormous quantities advantageously.In addition, prior art need can be used for the magnetic device of power adapters etc., and it can make the magnetization induction of this magnetic device under low current level improve.
Summary of the invention
These and other problem and technological merit are usually solved or are avoided by the preferred embodiments of the present invention, comprise power converter, and it comprises power switch, be used to the magnetic device controlling the controller of its switching frequency and have non-homogeneous gap.In one embodiment, this power converter comprises power switch and is coupled to this power switch and has the magnetic device in non-homogeneous gap.This power converter also comprises controller, and described controller has and is configured to the status detection device that sensing is represented the power converter power output.The control circuit of this controller is configured to control according to state the switching frequency of this power switch, and the duty ratio of controlling this power switch is to regulate the output characteristic of this power converter.
On the other hand, the invention provides the magnetic device with non-homogeneous gap, it comprises the magnetic core with first core segment and second core segment, and wherein second core segment of this magnetic core has leg, and first core segment of itself and this magnetic core forms the gap.Leg one end of second core segment of this magnetic core can have the cross-sectional area that reduces or the through hole that sets within it to form non-homogeneous gap.Alternatively, the leg of second core segment of this magnetic core conical region that can have the shaped like chips part that is arranged on its end or be positioned at its end is to form non-homogeneous gap.In optional embodiment, this magnetic device can comprise another magnetic core with first core segment and second core segment, and wherein second core segment of this another magnetic core has leg, and first core segment of itself and this magnetic core forms the gap.The gap of these two magnetic cores forms the non-homogeneous gap of this magnetic device.
The content of front has quite broadly been summarized structure of the present invention and technological merit, thereby detailed description of the present invention is more readily understood below making.Other structure of the present invention and advantage will be described below, and it has formed the theme of claim of the present invention.One skilled in the art will appreciate that notion disclosed herein and specific embodiment can be used as the basis at an easy rate, change or design other structure or be used to implement the step of the identical purpose of the present invention.Those skilled in the art will also be appreciated that these equivalent structures do not break away from the spirit and scope of the present invention that set by appending claims.
Description of drawings
In order more intactly to understand the present invention, come the present invention is carried out following description below in conjunction with accompanying drawing, wherein:
Fig. 1 shows the schematic diagram of embodiment of the power adapters of the power converter that adopts constructed in accordance with the principles;
Fig. 2 shows the voltage and current of the exemplary power transducer of operating according to the principle of the invention and the waveform between the time under continuous conduction mode;
Fig. 3 shows the schematic diagram of embodiment of controller of switching frequency that configuration is used to control the power converter of constructed in accordance with the principles;
Fig. 4 shows the perspective view of embodiment of the magnetic device of constructed in accordance with the principles to Figure 13.
Unless otherwise indicated, generally speaking, corresponding numeral and mark in the different accompanying drawings are represented corresponding part, and for for purpose of brevity, can be described no longer again after occurring for the first time.These accompanying drawings are used to illustrate the relevant portion of exemplary embodiment.
Embodiment
Describe the formation and the use of exemplary embodiment of the present below in detail.Yet, should be understood that the invention provides multiple creative notion applicatory, it can be used in the multiple version of specific context.Specific embodiment described herein only is an example of making and use ad hoc fashion of the present invention, is not limitation of the scope of the invention.
In context, will the present invention be described at exemplary embodiment, be called power converter, it comprises power switch, be used to the magnetic device controlling the controller of its switching frequency and have non-homogeneous gap.Although will in the environment of power converter, describe principle of the present invention,, adopt any application of the power conversion apparatus comprise power switch, controller and magnetic device, as power amplifier or electric machine controller all in wide region of the present invention.
Because it is simple and low-cost, the reaction type power converter is often used in the low power applications, as is used for the power adapters of printer.Adopt the power adapters of reaction type power converter typically to be designed for operation continuously under the high-output power level.Yet the load of presenting to power adapters often is the time period that changes and can not operate prolongation usually on maximum power level as the load that is provided by printer and personal computer.The design consideration that is used for the power adapters of these occasions is the power conversion efficiency under underloading and intermediate load condition.
The reaction type power converter is typically designed under substantially invariable switching frequency and operates.The switching frequency that other power converter topological structure is designed to reduce to increase along with load is operated.In order to reduce electromagnetic interference (EMI), this switching frequency can be modulated, and usually with random fashion, produces little frequency departure round the nominal switching frequency.The change at random of switching frequency has been expanded the frequency spectrum of electromagnetic interference frequency component, and has reduced its peak value spectrum value.The peak value spectrum value that this reduces can provide significant reduction in the component that increases, with the electromagnetic interference that change action produced of management by the power converter power train.Yet these small frequency deviation effects and power conversion efficiency in the design of the primary element of power train such as magnetic device (as transformer) and power switch are very illusive basically.
As introducing here like that, along with power converter offers the increase of the power output of load, the switching frequency increase of one or more switches of this power converter.The switching frequency that increases has reduced the peak current that flows through the magnetic device that adopts in the power link topological structure, particularly in reaction type power link topological structure.Correspondingly, the peak flux in the magnetic device reduces.Ripple current in power converter filtering unit such as the outputting inductance also reduces.The size of magnetic device such as transformer can advantageously reduce.Therefore, power converter not only can use smaller transformer, and power converter also can remain on the operation of continuous conduction mode (CCM) under lower power levels, makes and improve power conversion efficiency under lower power levels.Along with reducing power output with the power conversion efficiency of further raising under lower power levels, technology of controlling (as changing) switching frequency according to the state of expression power converter power output (as the power output level of the electric current or the sensing of sensing) can be used to most or all reduce the switching frequency of one or more switches of power converter on the loading ranges.During low-power operation, the reduction of switching frequency can reduce switching loss, and it will become the very little part of whole power converter loss.Therefore the reduction of switching frequency has improved the power conversion efficiency during low-power operation.
Switching frequency can be controlled as with the power output of power converter proportional, and corresponding with its input voltage of choosing.Preferably, can adopt restriction of lower switching frequency as 20 KHz (kHz), in human earshot, operate preventing.In very low power output level, as maximum rated power output 1% or still less, also can adopt pulse (burst) pattern mode of operation to come the power controlling transducer.Under the pulse operation pattern, the change action of one or more switches of the power link of power converter temporarily stops, and output filter capacitor provides power to load simultaneously.Partly after (or slightly) discharge, the change action of power link recovers at output filter capacitor.Therefore, in non-pulse operator scheme process, switching frequency can be controlled as with the power output of power converter proportional.
Can be applied in the power link topological structure with the process that increases and reduce the parallel increase of carrying out of load on the power converter and reduce switching frequency, wherein the peak flux in the magnetic device depends on the load on the power converter.For example, the process of controlling switching frequency by the state of representing the power converter power output can be used in step-down (buck) or boost (boost) power link topological structure, comprise and isolating and non-isolated topology constructive variation, as the boost power link topological structure of power factor controlling.
With reference to figure 1, wherein show the schematic diagram of embodiment of the power adapters of the power converter that adopts constructed in accordance with the principles with controller 150.The power link (for example, feedback power link) of power converter (being also referred to as " feedback power transducer ") comprises the power switch Q that is coupled to AC power 110
Main, electromagnetic interference (EMI) filter 120, bridge rectifier 130 and input filter condenser C
In, with DC input voitage V
InOffer magnetic device (as isolating transformer or transformer T
1).Transformer T
1Having turn ratio is n: 1 elementary winding N
pWith secondary winding N
s, this turn ratio is selected as considering that the pressure on resulting duty ratio and the power link assembly provides output voltage V
OutTransformer T
1Also can comprise non-homogeneous gap as described below.
Power switch Q
Main(as the n slot field-effect transistor) controlled by pulse width modulator (" PWM ") 160, its power controlling switch Q
MainConducting in duty cycle range.Power switch Q
MainThe gate drive signal V that is produced in response to pulse width modulator 160 by control circuit 155
GAnd (be typically expressed as f with switching frequency
s) conducting.Duty ratio is by the output characteristic of pulse width modulator 160 controls (as regulating) with the adjustment power converter, as output voltage V
OUT, output current I
Out, or both combination.Feedback path 161 makes pulse width modulator 160 control these duty ratios, to adjust the output characteristic of power converter.Certainly, well-known to those skilled in the art is can adopt circuit isolated component such as optical isolator in feedback path 161, to keep the isolation of power converter input-output.
At transformer T
1Secondary winding N
sThe alternating voltage of last appearance is by diode D
1Rectification, the DC component that produces waveform is by comprising output filter capacitor C
OutThe low pass output filter and be coupled to output to produce output voltage V
OutDetector 170 sensings represent the state of power converter power output (as current sensing resistor R
CSIn electric current), and the frequency control circuit of control circuit 155 (FCC) 180 is configured to control in response to the electric current that senses that further describes below the power switch Q of (as modification, change, variation etc.) power converter
MainSwitching frequency.Control circuit 155 can be in the non-pulse operator scheme process of power converter and corresponding to selected input voltage V
InOr its voltage range is come power controlling switch Q
MainSwitching frequency.Provide voltage signal thereby can present feed-forward signal path 162 for frequency control circuit 180, so that can be based on input voltage V to it
InFeed-back frequency to power converter is controlled.For example, for given power output level, at high-voltage line input voltage V
InThe power switch Q that (as 230 volts of interchanges) are located
MainPeak current will be than at low-voltage line input voltage V
InThe peak current that (as 115 volts of interchanges) are located will hang down.Feed-forward signal path 162 can be used to compensation because input voltage V
InChange and change in 170 outputs of the detector that causes.At high-voltage line input voltage V
InThe place, power switch Q
MainSwitching frequency can reduce.Such as, at high-voltage line input voltage V
InThe place, power switch Q
MainSwitching frequency can be used as input voltage V
InFunction and reduce linearly.
During the first of duty ratio, flow through transformer T
1Elementary winding N
pElectric current I
Pri(as inductor current) is along with from inlet flow overpower switch Q
MainElectric current and increase.In the complementary portion of duty ratio (usually with power switch Q
MainComplementary duty cycle 1-D coexistence), power switch Q
MainBe converted to nonconducting state.As power switch Q
MainDuring shutoff, be stored in transformer T
1In the remanence energy make by diode D
1Current lead-through.Be coupled to output filter capacitor C
OutDiode D
1Provide and keep transformer T
1The successional path of magnetizing current.In the complementary portion of duty ratio, flow through transformer T
1Secondary winding N
sMagnetizing current reduce.Usually, power switch Q
MainBut duty ratio Be Controlled (as adjust), with holding power converter output voltage V
OutAdjustment or adjust the power converter output voltage V
Out
In order to adjust output voltage V
Out, in pulse width modulator 160, utilize the error amplifier (not shown) usually to output voltage V
OutValue or ratio value and reference voltage compare with the control duty ratio.This has formed the negative sense feedback arrangement, with output voltage V
OutAdjust to reference voltage level (ratio value).Bigger duty ratio means power switch Q
MainClosure in the long part of the switching cycle of power converter.
The energy store electricity sensor of feedback power link is incorporated into transformer T
1In as transformer T
1Magnetizing inductance.For high efficiency power transfer is provided, power converter operates in continuous conduction mode when the low-voltage line input voltage.Under this continuous conduction mode, as power switch Q
MainWhen opening (being closure or conducting) for the first time, flow through power switch Q
MainElectric current from the occasion of.As power switch Q
MainTurn-off (promptly open or non-conduction) and as diode D
1When opening, flow through diode D
1Electric current can not be reduced to zero.Active power switch such as field-effect transistor can be used for substituting diode D
1As synchronous rectifier, to improve power conversion efficiency.
With reference to figure 2, wherein show the voltage and current of the exemplary power transducer that operates in accordance with the principles of the present invention under the continuous conduction mode and the waveform between the time.Continuation is with reference to the power converter among the figure 1, the characteristic of before mentioning be used for power switch Q
MainGate drive signal V
G, transformer T
1Elementary winding N
pIn electric current I
Pri, and transformer T
1Secondary winding N
sIn electric current I
SecRelevant.Parameter " D " is represented the first of duty ratio.In first's process of duty ratio, transformer T
1Elementary winding N
pIn average current in Fig. 2, represent by parameter " I ".In first's process of duty ratio, transformer T
1Elementary winding N
pThe variation of middle electric current is represented by parameter " Δ I ".
The output voltage V of feedback power transducer under continuous conduction mode
OutCan roughly represent by equation (1):
V
out＝V
in·[D/(1-D)]·(1/n)，
Wherein D is power switch Q
MainDuty ratio (be power switch Q
MainOpen, the time portion of closure or turn on process), and " n " is transformer T
1Elementary winding N
pThe number of turn and secondary winding N
sThe ratio of the number of turn.Therefore, when operating in continuous conduction mode following time, the duty ratio of power converter is by input voltage V
InWith output voltage V
OutRatio decision.Equally, when operating in continuous conduction mode, the power output of power converter decision output current I
Out, and therefore this power output by transformer T
1Turn ratio control.For given transformer T
1Turn ratio n: 1 (it is by power switch Q
MainRated voltage and limited with the needs that obtain high power conversion efficiency with the operation of quite high duty ratio), power switch Q
MainIn current average determined by load.Power switch Q
MainIn current average be independent of switching frequency.
The operational feedback power converter particularly conventional method of power adapters is to use substantially invariable switching frequency.When underload very, as previously mentioned, power converter can be operated under the pulse operation pattern, and wherein power converter is forbidden off and on to reduce underloading or no-load power consumption.As introducing here, controller 150 monitorings represent the state of power converter power output (for example, such as passing through current-sense resistor R
CsOr the electric current of the sensing of the peak current of the sensing of other current sensing element such as current sense transformer), with the switching frequency of power controlling transducer.Alternatively, controller 150 can be monitored other state of representing the power converter power output, as the electric current in other power link assembly (as secondary side components), with the switching frequency of power controlling transducer.Along with at the current-sense resistor R shown in Fig. 1 and Fig. 3
CsPeak current in (or other current sensing element) increases, and the switching frequency of power converter increases.For example, the switching frequency of power converter can be increased to the 130kHz under the peak power output level from the 20kHz under the low power output level.The low restriction of power converter switching frequency needs, and as noted, operates in the frequency range of human hearing preventing.
With reference to figure 3, wherein show the schematic diagram of embodiment of switching frequency controller 300 that configuration is used to control the power converter of constructed in accordance with the principles.Controller 300 can be applicable in the feedback power transducer shown in Figure 1, thereby when passing through power switch Q
MainThe switching frequency of peak current control (as increasing) power converter when changing (as increasing).Be coupled to the timing capacitor C of the RT/CT input (its control generator frequency) of pulse width modulator 330
TWith timing resistor device R
TBe set to the nominal switching frequency of power converter.Power converter comprises and power switch Q
MainThe current-sense resistor R of source terminal coupled in series
Cs
By diode D
2Be connected to current-sense resistor R
CsCapacitor C
2On behalf of the state of power converter power output, the detector 310 that forms detects (as flow through power switch Q
MainPeak current), this power output is at capacitor C
2Two ends produce basically and current-sense resistor R
CsIn the proportional voltage of peak current.Detector 310 according to controller 300 comprises amplifier A alternatively
1, with will be at current-sense resistor R
CsThe voltage that two ends sense is increased to higher level.At capacitor C
2The voltage that two ends produce and the resistor R of detector 310
2Produce amplifier Q together
1The base current of (as bipolar transistor), this electric current produce then and are used for bipolar transistor Q
1Collector current.Certainly, in optional embodiment, can change by suitable circuit and make field-effect transistors replace bipolar transistor Q
1Bipolar transistor Q
1Collector current flow through by transistor Q
2, Q
3The current mirror that forms.This mirror currents is coupled to timing capacitor C
T, to work as current-sense resistor R
CsIn the switching frequency of peak current control (as increasing) power converter when changing (as increasing).The frequency control circuit 320 of controller 300 comprises timing capacitor C
T, timing resistor device R
T, bipolar transistor Q
1And current mirror.Therefore, comprise that the control circuit of frequency control circuit 320 and pulse width modulator 330 is in response to switching frequency and the power controlling switch Q of detector 310 to control one or more power switchs
MainDuty ratio, thereby adjust the output characteristic of power converter.The control circuit configuration of controller 300 shown in Figure 3 is used for providing according to the variation of peak switch current the continuous variation of switching frequency.When current mirror did not produce electric current, the low restriction of switching frequency was by the timing resistor device R corresponding to this situation
TProvide.
The power that is transferred to output from the input of power converter depends in each switching cycle stored at transformer T
1In energy change and the product of switching frequency.The power that is transferred to the power converter output can be represented by equation (2):
P＝f
s·[0.5·L·|(I+ΔI)
2-(I-ΔI)
2|]＝f
s·L·I·ΔI，
Wherein P is the power output of power converter, f
sBe the switching frequency of power converter, L is transformer T
1Elementary winding N
pMagnetizing inductance, Δ I as top pointing out, is transformer T in duty ratio first process as shown in Figure 2
1Elementary winding N
pIn electric current change, and I is that each periodic flow is crossed transformer T in first's process of duty ratio
1Elementary winding N
pElectric current I
PriMean value.
Flow through transformer T
1Elementary winding N
pElectric current I
PriMean value I also by as transformer T
1Turn ratio n: the power output of 1 function decides.Keep constant power output level can make the changing value among the electric current Δ I reduce when increasing switching frequency.Transformer T
1In peaking flux density B
PeakProportional with current peak, shown in equation (3):
B
peak∝I+ΔI/2。
Therefore, the changing value that reduces among the electric current Δ I has reduced peaking flux density B, and this can make it possible to use littler transformer core.In the peak power operating process, because higher switching frequency comprises transformer T
1Core loss can increase significantly in interior switching loss.Yet printer power adapters and the power adapters that is coupled to other load typically only require high-power short pulse.Increasing in short-term of switching frequency usually will be minimum for the group effect of power converter inside heating.
Peak current can be used as the deciding factor that the power converter switching frequency changes.Owing to flow through power switch Q
MainPeak current and transformer T
1In flux density proportional, this will advantageously prevent the saturated of transformer core, and the input voltage V of power converter no matter
In, output voltage V
Out, or other mode of operation how.
The switching frequency that reduces power converter when load or power output reduce can improve the power conversion efficiency under the underloading situation.Therefore, switching frequency can change in the total power range of power converter basically, except the restriction that is applied by the lower frequency limit value.In one embodiment, switching frequency can be proportional with the power output level in the opereating specification of power converter basically, have optionally for the restriction of switching frequency and with the selection input voltage V of power converter
InIt is corresponding.
When the design power adapter, the designer had typically both paid close attention to the efficient that increases power transfer, paid close attention to the substantially constant that keeps cost simultaneously again, perhaps reduced cost when keeping performance characteristics such as power conversion efficiency constant.That introduces here increases switching frequency and can make with the process of the flux density that reduces the magnetic device SMIS and reduce cost by allowing the core size to reduce at the peak power place, keep the substantially constant of normal power performance characteristic simultaneously.
Can utilize when the higher load level process that increases switching frequency to increase efficient than the underload level time, keep the substantially constant of cost simultaneously.In order to realize this target, can in magnetic device (as transformer), adopt the zone of the core cross-sectional area that reduces, change on the flux path of flux, to produce effectively.In the peak power pulses process, the core zone with the cross-sectional area that reduces is saturated, elongates this gap (as forming non-homogeneous gap as described below) effectively and reduces the magnetizing inductance of transformer.Owing to reducing of transformer magnetizing inductance under high electric current/flux level, the slope of electric current (with respect to the time) will increase.Yet, the increase of the switching frequency under the high capacity level has reduced the time durations that electric current rises, thereby be associated with the reduction of transformer magnetizing inductance by increase the power converter switching frequency, make circuit designers can holding current changing value Δ I more near constant.
Thereby the gap in the transformer core can cause tangible power loss owing to make fringing flux flow through the conduction winding nearby.Conductive material can not be arranged near the centre in gap as the Transformer Winding that forms around transformer central authorities leg.Thereby this has reduced fringing flux in closing on winding by the centre that flux is accumulated in the transformer leg, and this centre is winding zone farthest around the distance.
With reference to figure 4, wherein show the perspective view of embodiment of the magnetic device of constructed in accordance with the principles.This magnetic device (as transformer) comprises " E-I " magnetic core or has first core segment (as " I " core segment 401) and the core of second core segment (as " E " core segment 402).In Fig. 4 and figure afterwards, first core segment (as " I " core segment 401) is shown as from second core segment (as " E " core segment 402) and upwards is provided with, thereby the separation diagrammatic sketch of two core assemblies is provided.Equally, illustrate with the similar structures of the magnetic device embodiment that describes and will carry out mark according to following accompanying drawing with similar Reference numeral.
When the structure of transformer was finished, " I " core segment 401 was arranged in the top of the outer legs (one of them is designated 404) of " E " core segment 402.Central authorities' leg 403 forms shorter than outer legs 404, thereby is formed for the gap 406 of magnetic flux.Can form the air gap or comprise that the gap 406 in other nonmagnetic substance gap has reduced the flux in the core, thereby reduce core saturated trend under high levels of current.However, gap 406 included compared, reduced the magnetizing inductance of transformer with the transformer that does not have such gap.Gap 406 also can be formed by nonmagnetic substance such as plastics sept, and the combination that maybe can comprise magnetic material such as powder magnetic material and non magnetic adhesive is to form distributed gap.
With reference to figure 5, wherein show the perspective view of embodiment of the magnetic device (as transformer) of constructed in accordance with the principles.Except " E-I " magnetic core or core and air (or other nonmagnetic substance) gap 406, the end of central leg 403 (as upper end 407) has the diameter that reduces, to form the non-homogeneous cross section of core.The cross-sectional area of central leg 403 upper ends 407 reduce make that its upper end 407 is saturated under higher levels of current, simultaneously can be unsaturated under low current level more.The diameter that reduces of central authorities leg 403 upper ends 407 is more forming longer gap under the high magnetic flux level effectively, and this has reduced the magnetizing inductance of transformer under higher levels of current.In other words, the cross-sectional area that reduces of gap 406 and central leg 403 upper ends 407 has formed non-homogeneous gap, but it provides the change level that depends on the magnetizing inductance of levels of current in the magnetic device.Therefore, this magnetic device has advantageously provided for the variable core saturated level of part core under the variable current level.
Structure shown in Figure 5 provides more odds for effectiveness for power converter, because it more closely gathers its centre with the line of flux in the non-homogeneous gap, even still can be like this when the middle body of core is partly saturated.Therefore fringing flux and the loss that is associated with fringing flux reduce.Certainly, in wide region of the present invention, the stepped diameter of alternative central leg 403 upper ends 407 is that central leg 403 upper ends 407 can be taper, and are saturated thereby permission produces more uniform core when the magnetic flux in core increases with formation non-homogeneous gap as shown in Figure 5.As non-homogeneous gap in the central leg of core substitute or additional be that the non-homogeneous gap with the cross-sectional area that reduces can be formed on the outer legs 404 to obtain similar effect.Therefore, the variation of core (or core leg) cross-sectional area can be represented in term used herein " non-homogeneous gap ", and can comprise stepped gap and tapered gaps.
The disappearance that core is saturated under small throughput and levels of current or reduce in transformer to produce high magnetizing inductance, and be implemented in efficient operation under the low power output level.The transformer that is configured to have the core leg that reduces cross-sectional area also can be configured to do not have the gap in fact, produces in the mode that can control with the high magnetizing inductance that is implemented in transformer saturated under the high levels of current.
With reference to figure 6, wherein show the perspective view of embodiment of the magnetic device (as transformer) of constructed in accordance with the principles.Except " E-I " magnetic core or core and air (or other nonmagnetic substance) gap 406, central leg 403 comprises boring and in through hole 408 wherein, it makes this core saturated under higher levels of current.In other words, gap 406 and the through hole 408 in central leg 403 have formed the non-homogeneous gap that is arranged in this magnetic device.Alternative or by way of parenthesis, the through hole 408 in gap 406 and the central leg 403 can be with respect to a formation in the outer legs 404.
With reference to figure 7, wherein show the perspective view of embodiment of the magnetic device (as transformer) of constructed in accordance with the principles.Except " E-I " magnetic core or core and air (or other nonmagnetic substance) gap 406, transformer can comprise shaped like chips part (as the toroidal cores sheet part) 409 that is arranged in central leg 403 1 ends, and it makes this core saturated under higher levels of current.For the purpose of vision was clear, Fig. 7 showed the shaped like chips part 409 that is positioned on the central leg 403.In fact, shaped like chips part 409 can be arranged on the central leg 403 without limitation.Also can use the non-magnetic spacer thing that shaped like chips part 409 is arranged on the centre of " I " core segment 401 and central leg 403, with further reduction fringing flux and the loss that is associated.Shaped like chips part 409 provides practical structure, to form through hole in the central leg 403 of this core.This shaped like chips part 409 can change on height and length to some extent, adjusts inductance so that the bidimensional degree of freedom to be provided with respect to current curve.Gap 406 and shaped like chips part 409 have formed the non-homogeneous gap in the magnetic device.Alternative or additionally, the shaped like chips part 409 on the central leg 403 can be with respect to a formation in the outer legs 404.
With reference to figure 8, wherein show the perspective view of embodiment of the magnetic device (as transformer) of constructed in accordance with the principles.Except " E-I " magnetic core or core and air (or other nonmagnetic substance) gap 406, form the diameter that reduces of the upper end of central leg 403 by placing shaped like chips part (as cylindrical core sheet part) 410 thereon with the diameter that reduces.For the purpose of vision was clear, Fig. 8 showed the shaped like chips part 410 that is positioned on the central leg 403.In fact, shaped like chips part 410 can be arranged on the central leg 403 without limitation.Alternatively, shaped like chips part 410 can be formed with distributed gap, to eliminate the needs to gap 406.Shaped like chips part 410 can form has nonmagnetic substance such as plastics sept, and the combination that maybe can comprise magnetic material such as powder magnetic material and non magnetic binding agent to be forming distributed gap, thereby advantageously eliminates the needs to gap 406.In the shaped like chips part 409 that the structure of before mentioning also may be used on illustrating and describing with reference to figure 7.Gap 406 and shaped like chips part 409 have formed the non-homogeneous gap that is positioned at magnetic device, and shaped like chips part 409 can strengthen the accuracy in gap 406.Alternatively or additionally, the shaped like chips part 410 on the central leg 403 can be with respect to a formation in the outer legs 404.
With reference to figure 9, wherein show the perspective view of embodiment of the magnetic device (as transformer) of constructed in accordance with the principles.Except " E-I " magnetic core or core, central leg 403 can comprise the conical region 411 that is positioned at one end place, and to reduce the cross-sectional area of central leg 403, this makes that this core can be saturated under higher levels of current.In other words, conical region 411 has formed the non-homogeneous gap in the magnetic device.Alternatively or additionally, being arranged in the conical region 411 of central leg 403 1 ends can be with respect to a formation of outer legs 404.
Non-homogeneous gap in the magnetic device can form by a core leg part is ground away traditionally.Owing to need carry out grinding operation discretely, the cost that this process has increased core has reduced the accuracy of gap length simultaneously owing to the inexactness of Ginding process.In order to reduce manufacturing cost and to increase the accuracy of magnetic device intermediate gap, non-homogeneous gap length dimension, introduce a kind of method that forms non-homogeneous gap here.
With reference to Figure 10, wherein show the perspective view of embodiment of the magnetic device (as transformer) of constructed in accordance with the principles.This transformer comprises and being coupled first magnetic core and second magnetic core (as two " E-I " magnetic cores or core) of (as be arranged side by side, directly be coupled or adjacent).First magnetic core comprises first core segment (as " I " core segment 1001) and second core segment (as " E " core segment 1002).The central leg 1003 of " E " core segment 1002 is shortened slightly to form first gap 1006.Second magnetic core comprises first core segment (as " I " core segment 1011) and second core segment (as " E " core segment 1012).The central leg 1013 of " E " core segment 1012 also is shortened to form second gap 1016.In this way, can adopt economic make to form non-homogeneous gap in the magnetic core of transformer.In other words, first gap and second gap 1006,1016 can be of different sizes (smaller than another gap as a gap, or the length difference in these gaps) to form non-homogeneous gap.Certainly, first gap and second gap 1006,1016 can form the multiple structure that comprises the structure that illustrates above.
With reference to Figure 11, wherein show the perspective view of embodiment of the magnetic device (as transformer) of constructed in accordance with the principles.This transformer comprises comprising of being coupled and first magnetic core of and the similar element described shown with reference to Figure 10 and the further structure of second magnetic core.Yet in the present embodiment, " I " core segment 1001,1011 shown in Figure 10 is formed single " I " core segment 1101.In this way, can adopt more cost effective structure to arrange to form the non-homogeneous gap of transformer.
With reference to Figure 12, wherein show the perspective view of embodiment of the magnetic device (as transformer) of constructed in accordance with the principles.This transformer comprises and being coupled first magnetic core and second magnetic core (as two " E-E " magnetic cores) of (as placed side by side, directly be coupled or adjacent).First magnetic core comprises first core segment (as " E " core segment 1201) and second core segment (as " E " core segment 1202).The central leg 1203 of " E " core segment 1202 is shortened a little to form first gap 1206.Second magnetic core comprises first core segment (as " E " core segment 1211) and second core segment (as " E " core segment 1212).The central leg 1213 of " E " core segment 1212 also is shortened to form second gap 1216.In this way, can adopt economic structure to arrange the non-homogeneous gap that forms magnetic core of transformer.In other words, first gap and second gap 1206,1216 can be of different sizes (more smaller than another gap as a gap, or these gaps have different length) to form non-homogeneous gap.Certainly, first gap and second gap 1206,1216 can form the multiple structure that comprises the structure that illustrates above.
With reference to Figure 13, wherein show the perspective view of embodiment of the magnetic device (as transformer) of constructed in accordance with the principles.This transformer comprises comprising of being coupled and first magnetic core of shown in Figure 12 and the similar element described and the further structure of second magnetic core.Yet in the present invention, " E " core segment 1201,1211 shown in Figure 12 is formed single " E " core segment 1301.In this way, can adopt more cost effective structure to arrange to form the non-homogeneous gap of transformer.
Therefore, introduced magnetic device here with non-homogeneous gap.In one embodiment, this magnetic device comprises first magnetic core with first core segment and second core segment (as " I " or " E " core segment), and wherein second core segment of this first magnetic core has the leg (as central authorities or outer legs) that forms first gap (as air gap or distributed gap) with first core segment of this first magnetic core.This magnetic device comprises also and has second magnetic core of first core segment and second core segment (as " I " or " E " core segment) that wherein second core segment of this second magnetic core has the leg (as central authorities or outer legs) that forms second gap (as air gap or distributed gap) with first core segment of this second magnetic core adjacent with first magnetic core.First gap and second gap have formed the non-homogeneous gap of magnetic device.For example, first gap can be littler than second gap, to form non-homogeneous gap.In addition, first core segment of first magnetic core and second magnetic core can be formed single core segment.
Power converter of describing before one skilled in the art will appreciate that comprises controller and the embodiment that operates the correlation technique of this power converter are only used for illustrative purpose.In addition, many other power converter topological structures can be all in wide region of the present invention, for example boost power transducer and single ended primary induction device power converter topological structure.Although described the power converter of the controller that comprises the switching frequency that is used for the power controlling switch under the situation of power converter, this controller also can be applicable to other system, as being not limited to power amplifier or electric machine controller.
In order to understand power converter better, please refer to Rudolph P.Severns and GordonBloom, Van Nostrand Reinhold company, New York, " modern DC-to-DC power switch mode power converter circuit " and the J.G.Kassakian in New York (1985), M.F.Schlecht and G.C.Verghese, " the power electronics devices principle " of Addison-Wesley (1991).Above-mentioned reference content is whole the introducing here by reference.
And, although described the present invention and advantage thereof in detail, should be understood that, do not breaking away under the prerequisite of the spirit and scope of the invention that limits as appended claims, multiple variation pattern, alternative can also be arranged here and shift gears.For example, above-described various procedures can realize by diverse ways, and be substituted by these processes or their combination.
In addition, the specific implementations of the application's the scope process, machine, product, material composition, device, method and the step that are not limited to describe in the specification.Those skilled in the art from what disclosure of the present invention will be readily appreciated that are, process, machine, manufacturing, material composition, device, method and the step that can carry out the essence identical function or obtain with the corresponding same effect of the embodiments described herein that have existed at present or will produce later on can be applied among the present invention.Correspondingly, appending claims is intended to these processes, machine, product, material composition, device, method or step are included in its scope.
Claims (20)
1. power converter comprises:
Power switch;
Be coupled to described power switch and have the magnetic device in non-homogeneous gap; And
Controller comprises:
Configuration is used for the status detection device that sensing is represented the power output of described power converter; And
Configuration is used for the switching frequency according to the described power switch of described State Control, and controls the duty ratio of described power switch, to adjust the output characteristic control circuit of described power converter.
2. power converter according to claim 1, wherein said control circuit configuration is used for reducing described switching frequency according to the reduction of described power output.
3. power converter according to claim 1, wherein said magnetic device comprises first core segment and second core segment, described second core segment has the leg that forms the gap with described first core segment, and an end of described leg has the cross-sectional area that reduces to form described non-homogeneous gap.
4. power converter according to claim 1, wherein said magnetic device comprises first core segment and second core segment, described second core segment has the leg that forms the gap with described first core segment, and an end of described leg has boring through hole within it to form described non-homogeneous gap.
5. power converter according to claim 1, wherein said magnetic device comprises first core segment and second core segment, and described second core segment has the shaped like chips part that forms the leg in gap and be arranged on described leg one end with described first core segment to form described non-homogeneous gap.
6. power converter according to claim 1, wherein said magnetic device comprises first core segment and second core segment, described second core segment has the leg that has conical region at the one end, to form the non-homogeneous gap of described magnetic device with described first core segment.
7. power converter according to claim 1, wherein said magnetic device comprises:
First magnetic core, it has first core segment and second core segment, and second core segment of described first magnetic core has the leg that forms first gap with first core segment of described first magnetic core, and
Second magnetic core, itself and the adjacent layout of described first magnetic core also have first core segment and second core segment, second core segment of described second magnetic core has the leg that forms second gap with first core segment of described second magnetic core, and described first gap and second gap form described non-homogeneous gap.
8. power converter according to claim 1, wherein said detector comprises resistor, capacitor and diode.
9. power converter according to claim 1, wherein said control circuit comprise that configuration is used to control the pulse width modulator that the frequency control circuit of switching frequency of described power switch and configuration are used to control the duty ratio of described power switch.
10. power converter according to claim 1, wherein said control circuit comprise timing capacitor, timing resistor device, amplifier, current mirror and pulse width modulator.
11. power converter according to claim 1, the state of the power output of wherein said representative power converter comprise in the output current of the electric current that is associated with described power switch and described power converter at least one.
12. power converter according to claim 1, wherein said control circuit configuration is used for providing continuously changing of described switching frequency according to the change of described condition.
13. power converter according to claim 1, wherein said control circuit are configured to the switching frequency of described power switch lower restriction are provided.
14. power converter according to claim 1, wherein said control circuit configuration is used for controlling the switching frequency of described power switch during the non-pulse operator scheme of described power converter.
15. power converter according to claim 1 wherein according to the selection input voltage of described power converter, provides the state of the power output of described representative power converter.
16. the method for an operand power transducer comprises:
Power switch is provided;
The magnetic device that will have non-homogeneous gap is coupled to described power switch;
Sensing is represented the state of the power output of described power converter;
Switching frequency according to the described power switch of described State Control; And
Control the duty ratio of described power switch, to adjust the output characteristic of described power converter.
17. method according to claim 16, the switching frequency of wherein said power controlling switch comprises: the reduction according to described power output reduces described switching frequency.
18. method according to claim 16, the switching frequency of wherein said power controlling switch comprises: the change according to described state provides continuously changing of described switching frequency.
19. method according to claim 16, the switching frequency of wherein said power controlling switch comprises: for the switching frequency of described power switch provides lower restriction.
20. method according to claim 16 wherein according to the selection input voltage of described power converter, provides the state of the power output of described representative power converter.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US12/486,493 US8643222B2 (en) | 2009-06-17 | 2009-06-17 | Power adapter employing a power reducer |
| US12/486,520 US8514593B2 (en) | 2009-06-17 | 2009-06-17 | Power converter employing a variable switching frequency and a magnetic device with a non-uniform gap |
| US12/486,520 | 2009-06-17 | ||
| US12/486,493 | 2009-06-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101931333A true CN101931333A (en) | 2010-12-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201010250715.4A Active CN101944857B (en) | 2009-06-17 | 2010-06-17 | Power adapter including power reducer |
| CN2010102420150A Pending CN101931333A (en) | 2009-06-17 | 2010-06-17 | The power converter that adopts changeable switch frequency and have the magnetic device in non-homogeneous gap |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
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| CN201010250715.4A Active CN101944857B (en) | 2009-06-17 | 2010-06-17 | Power adapter including power reducer |
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| CN (2) | CN101944857B (en) |
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| TWI493847B (en) * | 2011-07-26 | 2015-07-21 | System General Corp | Regulation circuit providing cable compensation for the power converter and method thereof. |
| CN109428493A (en) * | 2017-08-28 | 2019-03-05 | 欧姆龙株式会社 | LLC resonant converter |
| CN111711341A (en) * | 2020-06-29 | 2020-09-25 | 江南大学 | Power converter control method based on P-D feedback |
| CN112019019A (en) * | 2019-05-31 | 2020-12-01 | 广东美的制冷设备有限公司 | Drive control method, device, household appliance and computer readable storage medium |
| CN115004530A (en) * | 2022-01-28 | 2022-09-02 | 英诺赛科(苏州)半导体有限公司 | GaN-based switch mode power supply with planar transformer |
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| CN107026571A (en) * | 2016-12-26 | 2017-08-08 | 国网江西省电力公司电力科学研究院 | A kind of switching power unit |
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Also Published As
| Publication number | Publication date |
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| CN101944857A (en) | 2011-01-12 |
| CN101944857B (en) | 2014-09-17 |
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Application publication date: 20101229 |