CN104617776A - Control method of ultra-wide input voltage range DC-DC power flyback converter - Google Patents
Control method of ultra-wide input voltage range DC-DC power flyback converter Download PDFInfo
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- CN104617776A CN104617776A CN201410506195.7A CN201410506195A CN104617776A CN 104617776 A CN104617776 A CN 104617776A CN 201410506195 A CN201410506195 A CN 201410506195A CN 104617776 A CN104617776 A CN 104617776A
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- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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Abstract
The invention discloses a control method of an ultra-wide input voltage range DC-DC power flyback converter. A voltage-controlled oscillation frequency control method is mainly utilized to satisfy the ultra-wide input voltage range of a photovoltaic power generation system; when the input voltage changes, the voltage of the feedback winding of a transformer also changes and the oscillation frequency of an IC is enabled to change, and therefore, the ultra-wide input voltage range of a photovoltaic power generation system is realized. The control method is simple in control, low in cost, small in volume, and capable of effectively solving the problem of implementation by use of a two-stage circuit in the market; the output voltage can be directly converted by use of a single-stage circuit.
Description
Technical field
The present invention relates to a kind of Technology application of industrial power field, particularly relate to a kind of ultra-wide input voltage range DC-DC power source anti exciting converter control method.
Background technology
The input voltage range of present photovoltaic generating system is generally 150V-1000V, and traditional DC-DC power source converter, fixed frequency modes is utilized to carry out control inputs voltage ratio for 1:3, i.e. 120V-385V, the input voltage ratio that cannot meet photovoltaic generating system is 1:6.6, i.e. 150V-1000V, because input voltage is different, the linear change rate of transformer imput current is different, therefore the ON time of master power switch pipe and the turn-off time also different, when high voltage inputs, the ON time of power tube is very short, the instantaneous peak current flow through of power tube is very large, when power tube is closed, saturation condition may be there is.Result possible cause the electric current of power tube not to be linearly open, and efficiency reduces, and reliability reduces.
Summary of the invention
For problems of the prior art, the invention provides a kind of ultra-wide input voltage range DC-DC power source anti exciting converter control method, utilize VCO control method for frequency, meet photovoltaic generating system ultra-wide input voltage range, when input voltage changes, the voltage of transformer feedback winding also changes, and the frequency of oscillation of IC is also changed, thus realizes photovoltaic generating system ultra-wide input voltage range.
Technical solution of the present invention is: a kind of ultra-wide input voltage range DC-DC power source anti exciting converter control method, utilize VCO control method for frequency, namely in oscillating circuit, adopt voltage-controlled components and parts to carry out control frequency, namely change ON time and the frequency of switching tube, realize photovoltaic generating system ultra-wide input voltage range.
The present invention removes the control of reference voltage to timing resistor, introduce a variable voltage to timing resistor and error amplifier, after electric pressure converter is arranged on error amplifier and between voltage controlled oscillator, the change that error amplifier accepted whole output voltage is afterwards placed on a simple 3.3V voltage-stabiliser tube, when input voltage is low, export full load, the duty ratio of switching tube will more than 50%, the input voltage of voltage controlled oscillator will reach 7V, timing capacitor and timing resistor during startup, they determine maximum operation frequency, when starting in the present invention, timing capacitor selects 220PF, timing resistor selects 27K, their frequency of oscillation is 140KHZ to the maximum, when the input voltage of transformer feedback winding is greater than 3.3V, voltage controlled oscillator starts vibration, this oscillator can produce sawtooth waveforms, its frequency of oscillation is determined by resistance and electric capacity, when the voltage feeding back winding becomes large, the frequency of voltage controlled oscillator reduces to 75KHZ by 140KHZ.
Voltage controlled oscillator is in oscillating circuit, adopt voltage-controlled components and parts to carry out control frequency, and if direct voltage is as voltage-controlled control voltage, voltage controlled oscillator can be made into frequency adjustment signal source easily; Voltage-controlled components and parts are all generally with variable capacitance diode, its capacitance is subject to the control of input voltage VIN, during VIN change, namely frequency of oscillation (f) is caused to change, therefore voltage controlled oscillator is in fact exactly the converter of a kind of voltage to frequency, linear relationship time between its characteristic instantaneous frequency fv and control voltage Vc, in the range of linearity, this linearity curve can represent in order to lower equation: fv (t)=fo+kvvc (t), in formula, kv is characteristic curve, it caused by representation unit control voltage angular frequency change size.
Described anti exciting converter is made up of transformer, power switch pipe, output rectifying tube, output filter circuit, voltage feedback circuit, oscillating circuit.
Anti exciting converter work has two kinds of patterns, i.e. discontinuous mode, continuous mode; When underloading, anti exciting converter is operated in discontinuous mode; When heavy duty, anti exciting converter is operated in continuous mode; Discontinuous mode is that transformer releases energy completely, and continuous mode is transformer incomplete release energy; Its satisfy condition for: L >=V*TON/2IT is discontinuous mode, and L < V*TON/2IT is continuous mode; Its primary side inductive current is all by VIN/LP linear change; In a continuous mode, the utilance of main power component and transformer all can improve, and electric current is all continuous print at first siding ring and second siding ring, and the ripple current of output filter capacitor is very large.
The invention has the beneficial effects as follows: the present invention controls simply, reduce cost, reduce volume, can effectively solve by the problem that two-stage circuit realizes on market, available single-level circuit is directly converted to output voltage.
Accompanying drawing explanation
Fig. 1 is inverse excitation type converter block diagram of the present invention;
Fig. 2 is present system flow chart;
Fig. 3 is operation principle schematic diagram of the present invention;
Fig. 4 is characteristic instantaneous frequency of the present invention and control voltage graph of relation.
Embodiment
Below in conjunction with the drawings and specific embodiments, technical solution of the present invention is described in further detail.
As shown in Figure 1, Figure 2, Figure 3, Figure 4, Fig. 1 is inverse excitation type converter block diagram of the present invention; Fig. 2 is present system flow chart; Fig. 3 is operation principle schematic diagram of the present invention; Fig. 4 is characteristic instantaneous frequency of the present invention and control voltage graph of relation.
Ultra-wide input voltage range DC-DC power source anti exciting converter control method, utilize VCO control method for frequency, namely in oscillating circuit, adopt voltage-controlled components and parts to carry out control frequency, namely change ON time and the frequency of switching tube, realize photovoltaic generating system ultra-wide input voltage range.
As Fig. 3, the present invention removes the control of reference voltage to timing resistor, introduce a variable voltage to timing resistor and error amplifier, after electric pressure converter is arranged on error amplifier and between voltage controlled oscillator, the change that error amplifier accepted whole output voltage is afterwards placed on a simple 3.3V voltage-stabiliser tube, when input voltage is low, export full load, the duty ratio of switching tube will more than 50%, the input voltage of voltage controlled oscillator will reach 7V, timing capacitor when C7 is startup, R10 is timing resistor, they determine maximum operation frequency, when starting in the present invention, timing capacitor selects 220PF, timing resistor selects 27K, their frequency of oscillation is 140KHZ to the maximum, when the input voltage of transformer feedback winding is greater than 3.3V, voltage controlled oscillator starts vibration, this oscillator can produce sawtooth waveforms, its frequency of oscillation due to IC2845 the 4th pin be connected resistance and electric capacity determine, when the voltage feeding back winding becomes large, the frequency of voltage controlled oscillator reduces to 75KHZ by 140KHZ.
Voltage controlled oscillator is in oscillating circuit, adopt voltage-controlled components and parts to carry out control frequency, and if direct voltage is as voltage-controlled control voltage, voltage controlled oscillator can be made into frequency adjustment signal source easily, voltage-controlled element is all generally with variable capacitance diode, its capacitance is subject to the control of input voltage VIN, during VIN change, namely frequency of oscillation (f) is caused to change, therefore voltage controlled oscillator is in fact exactly the converter of a kind of voltage to frequency, graph of relation between its characteristic instantaneous frequency fv and control voltage Vc as shown in Figure 4, in figure, natural frequency during centre frequency fo when not having additional control voltage within the specific limits, linear relationship time between fv and vc, in the range of linearity, this linearity curve can represent in order to lower equation: fv (t)=fo+kvvc (t), in formula, kv is characteristic curve, it caused by representation unit control voltage angular frequency change size.
Described anti exciting converter is made up of transformer, power switch pipe, output rectifying tube, output filter circuit, voltage feedback circuit, oscillating circuit.
Anti exciting converter work has two kinds of patterns, i.e. discontinuous mode, continuous mode; When underloading, anti exciting converter is operated in discontinuous mode; When heavy duty, anti exciting converter is operated in continuous mode; Discontinuous mode is that transformer releases energy completely, and continuous mode is transformer incomplete release energy; Its satisfy condition for: L >=V*TON/2IT is discontinuous mode, and L < V*TON/2IT is continuous mode; Its primary side inductive current is all by VIN/LP linear change; In a continuous mode, the utilance of main power component and transformer all can improve, and electric current is all continuous print at first siding ring and second siding ring, and the ripple current of output filter capacitor is very large.
Real case:
1: power output: 17W
2: output voltage :+5V@1A MAX
+12V@1A MAX
3: input voltage: 150VDC--1000VDC
4: maximum input voltage: 1000VDC
Correlation computations:
PO=5V*1A+12V*1A=17W
Iav(max)=PO/ηVin=17W/0.8*150V=0.14A
Ipk=5.5PO/VIN=5.5*17W/150VDC=0.62A
LP=D*VIN/Ipk*f=0.5*150VDC/0.62A*140KHZ=0.86mH
Bmax=3500GS/2*2
1/
2=1300GS
lg=0.4π*LP*Ipk
2*1000000000/Ae*Bmax
2=0.4*3.14*0.86mH*0.62A*0.62A*1000000000/0.6cm
2*1300GS
2=0.046cm
Np=1000 LP/100mH1/2=93TS
NS1=(VO1+VF)*(1-Dmax)*NP/Dmax*VIN=(12V+1V)*0.5*93TS/0.5*150V=8TS
NS2=(VO2+VF)*(1-Dmax)*NP/Dmax*VIN=(5V+0.5V)*0.5*93TS/0.5*150V=4TS。
The present invention controls simply, reduces cost, and reduce volume, can effectively solve by the problem that two-stage circuit realizes on market, available single-level circuit is directly converted to output voltage.
Although the present invention is with preferred embodiment openly as above, they are not for limiting the present invention, anyly haveing the knack of this those skilled in the art, without departing from the spirit and scope of the invention, from when making various changes or retouch, but same within protection scope of the present invention.
Claims (5)
1. a ultra-wide input voltage range DC-DC power source anti exciting converter control method, it is characterized in that: utilize VCO control method for frequency, namely in oscillating circuit, adopt voltage-controlled components and parts to carry out control frequency, change ON time and the frequency of switching tube, realize photovoltaic generating system ultra-wide input voltage range.
2. ultra-wide input voltage range DC-DC power source anti exciting converter control method according to claim 1, it is characterized in that: remove reference voltage to the control of timing resistor, introduce a variable voltage to timing resistor and error amplifier, after electric pressure converter is arranged on error amplifier and between voltage controlled oscillator, the change that error amplifier accepted whole output voltage is afterwards placed on a simple 3.3V voltage-stabiliser tube, when input voltage is low, export full load, the duty ratio of switching tube will more than 50%, the input voltage of voltage controlled oscillator will reach 7V, during startup, timing capacitor and timing resistor determine maximum operation frequency, frequency of oscillation is 140KHZ to the maximum, when the input voltage of transformer feedback winding is greater than 3.3V, voltage controlled oscillator starts vibration, oscillator can produce sawtooth waveforms, its frequency of oscillation is determined by resistance and electric capacity, when the voltage feeding back winding becomes large, the frequency of voltage controlled oscillator reduces.
3. ultra-wide input voltage range DC-DC power source anti exciting converter control method according to claim 1, it is characterized in that: described voltage-controlled components and parts are variable capacitance diode, its capacitance is subject to the control of input voltage VIN, during VIN change, namely causes frequency of oscillation (f) to change.
4. ultra-wide input voltage range DC-DC power source anti exciting converter control method according to claim 1, it is characterized in that: linear relationship when characteristic instantaneous frequency fv becomes with control voltage Vc, can be expressed as: fv (t)=fo+kvvc (t), described kv is characteristic curve, the size of the angular frequency change caused by representation unit control voltage; During described startup, timing capacitor selects 220PF; Described timing resistor selects 27K.
5. ultra-wide input voltage range DC-DC power source anti exciting converter control method according to claim 1, is characterized in that: anti exciting converter is made up of transformer, power switch pipe, output rectifying tube, output filter circuit, voltage feedback circuit, oscillating circuit; Anti exciting converter work has two kinds of patterns, i.e. discontinuous mode, continuous mode; When underloading, anti exciting converter is operated in discontinuous mode; When heavy duty, anti exciting converter is operated in continuous mode; Discontinuous mode is that transformer releases energy completely, and continuous mode is transformer incomplete release energy; Its satisfy condition for: L >=V*TON/2IT is discontinuous mode, and L < V*TON/2IT is continuous mode; Its primary side inductive current is all by VIN/LP linear change; In a continuous mode, the utilance of main power component and transformer all can improve, and electric current is all continuous print at first siding ring and second siding ring, and the ripple current of output filter capacitor is very large.
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105375777A (en) * | 2015-11-30 | 2016-03-02 | 深圳创维-Rgb电子有限公司 | Constant voltage output circuit, flyback switching power supply and electronic device thereof |
CN111010042A (en) * | 2019-12-24 | 2020-04-14 | 漳州科华技术有限责任公司 | Frequency modulation circuit, voltage feedback device and power supply equipment |
CN112600396A (en) * | 2020-12-31 | 2021-04-02 | 广州金升阳科技有限公司 | Flyback converter and control method thereof |
-
2014
- 2014-09-26 CN CN201410506195.7A patent/CN104617776A/en active Pending
Non-Patent Citations (1)
Title |
---|
杨恒: "超宽输入电压反激式开关电源的设计", 《超宽输入电压反激式开关电源的设计》 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105375777A (en) * | 2015-11-30 | 2016-03-02 | 深圳创维-Rgb电子有限公司 | Constant voltage output circuit, flyback switching power supply and electronic device thereof |
CN105375777B (en) * | 2015-11-30 | 2018-12-07 | 深圳创维-Rgb电子有限公司 | Constant voltage outputting circuit, reverse exciting switching voltage regulator and its electronic equipment |
CN111010042A (en) * | 2019-12-24 | 2020-04-14 | 漳州科华技术有限责任公司 | Frequency modulation circuit, voltage feedback device and power supply equipment |
CN112600396A (en) * | 2020-12-31 | 2021-04-02 | 广州金升阳科技有限公司 | Flyback converter and control method thereof |
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Application publication date: 20150513 |