CN104993470B - A kind of control mode of the active filter of DC link - Google Patents
A kind of control mode of the active filter of DC link Download PDFInfo
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- CN104993470B CN104993470B CN201510364986.5A CN201510364986A CN104993470B CN 104993470 B CN104993470 B CN 104993470B CN 201510364986 A CN201510364986 A CN 201510364986A CN 104993470 B CN104993470 B CN 104993470B
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- 238000001514 detection method Methods 0.000 claims abstract description 19
- 239000003990 capacitor Substances 0.000 claims description 25
- 238000005070 sampling Methods 0.000 claims description 21
- 230000002441 reversible effect Effects 0.000 claims description 12
- 230000005611 electricity Effects 0.000 claims description 11
- 238000004146 energy storage Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 22
- 238000010586 diagram Methods 0.000 description 7
- 230000035939 shock Effects 0.000 description 5
- 230000010349 pulsation Effects 0.000 description 4
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Abstract
The invention discloses a kind of control mode of the active filter of DC link, which propose using control active filter output voltage minimum or peak method, respectively reach improve main converter underloading in the case of efficiency and improve main converter dynamic property purpose;After peak detection circuit output valve is compared with active filter output voltage minimum or peak benchmark, error signal feeding voltage regulator is produced;The low-frequency ac electric current in active filter DC link is detected, is added with the output signal of voltage regulator, current reference signal is produced;The input current of active filter is detected, is compared with current reference signal, error signal feeding current regulator is produced, obtains modulated signal;PWM circuit is sent into, the drive signal of switching tube is obtained.
Description
Technical field
The present invention relates to a kind of control mode of the active filter of DC link, belong to the model of power electronic converter
Farmland.
Background technology
It is required for suppressing the mains ripple and electric current arteries and veins in DC link in power electronic converter field, many occasions
It is dynamic.For example, the power supply of Power Solid-state Radar Transmitter needs to provide the pulsating current of low frequency, the requirement of its input power is as far as possible flat
Straight formula, and low frequency pulsating power is output as, if requiring that the pulsating power is all undertaken by output storage capacitor, in order to ensure
The pulsation of output voltage is sufficiently small, it is necessary to the output storage capacitor of Large Copacity, so can significantly increase the volume and again of power supply
Amount.And for example, in single stage type PWM rectifier and the LED drive power of Alternating Current Power Supply, input power contains twice larger of input frequency
The flutter component of rate, and instantaneous output approximately constant, in order to match Instantaneous input power and power output, it is necessary to using appearance
The larger storage capacitor of amount, this electric capacity typically selects electrochemical capacitor.And electrochemical capacitor life is relatively low, with system bulk life time not
Matching.According to more than analysis, in DC link be used for undertake low frequency pulsating power big capacity electrolyte capacitor, it is necessary to
Reduce its capacitance using certain method, or even remove electrochemical capacitor.
, can be with by the way that in DC link parallel active filter, the pulsating power of low frequency is absorbed using active filter
Significantly reduce the capacitor's capacity needed on dc bus.DC port is seen as to the input port of active filter here,
Its general principle is the low-frequency harmonics electric current for detecting to need to filter out from converter, then controls the input electricity of active filter
Stream is equal thereto, so that the low frequency pulsating power in its offer system, plays the purpose for reducing dc-link capacitance.
For the active filter using Buck/Boost reversible transducers, when the Instantaneous input power of main converter is higher than
During power output, active filter works in Boost patterns, by unnecessary energy storage into its output capacitance;When instantaneous defeated
When entering power less than power output, active filter works in Buck patterns, and output capacitor releases energy.The active filter
Using double-closed-loop control, current inner loop control its input current tracking needs to filter out or need the low frequency pulsating electric current provided;For
Ensure the normal work of active filter, it is necessary to ensure that its output voltage is consistently higher than the voltage of input, it is therefore desirable to plus
Enter an outer voltage to control it.Existing scheme is the average value of control output voltage, i.e. sampling and outputting voltage, with
Average value benchmark is compared, obtained voltage error be added to after voltage regulator sampling obtain low frequency pulsating electricity
Flow on signal, be used as the given of current inner loop.When converter load reduction, due to the average value of active filter output voltage
Still it is higher compared with input voltage so that active filter has larger switching loss, effect during influence converter underloading
Rate.It is low frequency pulsating form in load further, since outer voltage bandwidth is relatively low so that the dynamic response of converter is slower
Application scenario, output voltage, which still has, certain to be fallen and overshoots, it is therefore necessary to improve the control mode of active filter.
The content of the invention
The purpose of the present invention is that the active filter of larger capacity electrochemical capacitor is substituted for being connected in parallel on being used on DC link
Ripple device, proposes the method using control active filter output voltage minimum and peak, improves converter underloading situation
Under efficiency and reduce converter dynamic of output voltage in shock load and fall.
The present invention uses following technical scheme to solve above-mentioned technical problem:
A kind of control mode of the active filter of DC link,
Active filter uses double-closed-loop control, the low frequency pulsating electric current filtered out needed for current inner loop tracking, outer voltage
The minimum or peak of active filter output voltage are controlled, specific control mode is:
The output voltage of active filter is detected using voltage sampling circuit, what is obtained with a fixed value and sampling is defeated
Go out voltage to subtract each other, its result is sent into peak detection circuit;Or directly by obtained output voltage feeding peakvalue's checking of sampling
Circuit;The former is the control mode of control active filter output voltage minimum, and the latter is control active filter output electricity
Press the control mode of peak;
The output valve of peak detection circuit is compared with active filter output voltage minimum or peak benchmark
After relatively, error signal feeding voltage regulator is produced;
The electric current in active filter DC link is detected using current sampling circuit, is filtered out after its DC component, with electricity
Press the output signal of adjuster to be added by add circuit, produce the reference signal of current inner loop;
The input current of active filter is detected, is compared with current reference signal, error signal feeding electric current is produced
Adjuster, so as to obtain modulated signal;Modulated signal is sent into PWM circuit, and switching tube is obtained by drive circuit
Drive signal.
This method provides a kind of active filter, and the active filter is Buck/Boost reversible transducers.
The Buck/Boost reversible transducers specifically include inductance, two switching tubes, storage capacitors, specifically, inductance
One end be reversible transducer an input, the other end of inductance connects one end of two switching tubes respectively;Wherein first
Another input of the other end connection reversible transducer of switching tube and one end of storage capacitor, the second switch pipe
The other end connects the other end of storage capacitor.
The active filter is connected in parallel on the main converter DC link of conventional electron circuit, for needed for reducing DC link
Filter capacitor capacitance.
When the Instantaneous input power of the main converter is higher than fluctuating output power, active filter works in Boost
Pattern;When the Instantaneous input power of the main converter is less than power output, active filter works in Buck patterns.
When the method using control active filter output voltage minimum, active filter is detected using voltage sampling circuit
The output voltage of ripple device, the output voltage obtained with a fixed value with sampling subtracts each other, and its result is sent into peakvalue's checking electricity
Road;
After the output valve of peak detection circuit and active filter output voltage minimum benchmark are compared, mistake is produced
Difference signal sends into voltage regulator;
The electric current in active filter DC link is detected using current sampling circuit, is filtered out after its DC component, with electricity
Press the output signal of adjuster to be added by add circuit, produce the reference signal of current inner loop;
The input current of active filter is detected, is compared with current reference signal, error signal feeding electric current is produced
Adjuster, so as to obtain modulated signal;Modulated signal is sent into PWM circuit, and switching tube is obtained by drive circuit
Drive signal.
When the method using control active filter output voltage peak, active filter is detected using voltage sampling circuit
The output voltage of ripple device, the output voltage that sampling is obtained sends into peak detection circuit;
After the output valve of peak detection circuit and active filter output voltage peak benchmark are compared, mistake is produced
Difference signal sends into voltage regulator;
The electric current in active filter DC link is detected using current sampling circuit, is filtered out after its DC component, with electricity
Press the output signal of adjuster to be added by add circuit, produce the reference signal of current inner loop;
The input current of active filter is detected, is compared with current reference signal, error signal feeding electric current is produced
Adjuster, so as to obtain modulated signal;Modulated signal is sent into PWM circuit, and switching tube is obtained by drive circuit
Drive signal.
The present invention uses above technical scheme compared with prior art, with following technique effect:
When converter load lightens, active filter output voltage is adaptively reduced with lightening for load, and
If using the method for traditional control output voltage average value, active filter output voltage remains in that higher in underloading
Value.Therefore the method for control active filter output voltage minimum proposed by the present invention can effectively reduce active during underloading
The switching loss of filter switch pipe, improves the light-load efficiency of converter.
When the method using control active filter output voltage peak, with traditional control output voltage average value
Method compare, when converter start after shock load when, because outer voltage voltage reference value is higher so that Voltage loop
Output is relatively higher, so as to obtain higher electric current loop benchmark so that active filter can provide more instantaneous pulsation work(
Rate, therefore main converter output voltage falls when can effectively reduce shock load, improves the dynamic response performance of converter.
Brief description of the drawings
Accompanying drawing 1 is the structural representation of changer system when active filter is applied in the case of pulse load;
Accompanying drawing 2 is the circuit theory diagrams of active filter;
Accompanying drawing 3 is the key operation waveforms of active filter;
Accompanying drawing 4 is the control block diagram of control active filter output voltage minimum method in the present invention;
Accompanying drawing 5 is the control block diagram of control active filter output voltage peak method in the present invention;
Accompanying drawing 6 is the circuit theory diagrams of the peak detection circuit used in the present invention;
Wherein,V in For the DC input voitage of whole converter,C o For output filter capacitor,i o For pulse load electric current,I o
For its average value,v o For output voltage;V o For the approximate input voltage of active filter,L a WithC a Respectively active filter
Input inductance and storage capacitor,Q 1WithQ 2For two switching tubes of active filter;i a Withv a The respectively input of active filter
Electric current and output voltage, ΔV a 、V a_min 、V a_max WithV a The respectively pulsating quantity of output voltage, minimum, peak and average
Value,Q 1_dr WithQ 2_dr Respectively switching tubeQ 1WithQ 2Drive signal,R 1WithR 2For active filter output voltage sampling resistor;G v
(s) andG c (s) be respectively voltage regulator and current regulator,V a_min_ref WithV a_max_ref Active filter respectively under two schemes
Ripple device output voltage minimum benchmark and peak benchmark,i a_ref The electric current obtained after DC component is filtered out for pulse load electric current
Benchmark,D 1、D 2For constitute peak detection circuit diode,R p 、R f For the resistance of peak detection circuit,C p For peak detection circuit
Electric capacity.
Embodiment
The present invention provides a kind of control mode of the active filter of DC link, to make the purpose of the present invention, technical side
Case and effect are clearer, clearly, and referring to the drawings and give an actual example that the present invention is described in more detail.It should be appreciated that this
The specific implementation of place description is not intended to limit the present invention only to explain the present invention.
The technical scheme to invention is described in detail below in conjunction with the accompanying drawings:
The concrete application occasion that accompanying drawing 1 gives using active filter to reduce DC link electric capacity, it is loaded
Electric current is low-frequency pulse form, and the pulsation in order to ensure output voltage is sufficiently small, it is necessary to which an energy-storage units load institute to provide
The pulsating power needed, and for the size of the storage capacitor that reduces output end, can use in an output end active filter in parallel
The mode of ripple device, pulsating power is provided using the active filter.It is pointed out that the applicable occasion of the present invention is not limited to
The situation of pulse load, every DC link parallel active filter in converter is used for reducing the occasion of filter capacitor,
Can be using the control method in the present invention.
Accompanying drawing 2 gives the circuit theory diagrams for the active filter that the present invention is used, and its topology is a Buck/Boost
Reversible transducer, above-mentioned Buck/Boost reversible transducers specifically include inductance, two switching tubes, storage capacitors, specifically, electric
One end of sense is an input of reversible transducer, and the other end of inductance connects one end of two switching tubes respectively;Wherein
Another input of the other end connection reversible transducer of one switching tube and one end of storage capacitor, the second switch pipe
The other end connect storage capacitor the other end.
When the input power of main converter is higher than instantaneous fluctuating output power, active filter works in Boost moulds
Formula, by unnecessary energy stores to storage capacitorC a In, when input power is less than instantaneous output, active filter work
In Buck patterns,C a Release energy there is provided insufficient section power, so as to handle the pulsation work(in load by the way of active
Rate.Working waveform figure in respective figure 3 can be seen that active filter and provide load pulse electric currenti o In AC compounenti a ,
Wheni a >When 0,C a Release energy, voltage reduction;Wheni a <When 0,C a Energy is absorbed, voltage rises.
Accompanying drawing 4 gives the control block diagram of control active filter output voltage minimum method proposed by the invention.
It is made up of subtraction circuit, peak detection circuit, voltage regulator, PWM modulator and drive circuit.Active filter is exported
Voltage passes through resistor voltage divider networkR 1、R 2After obtain voltage sampling signalv a_f , then with a fixed valueV set Subtractv a_f , obtain
Value obtain the value of feedback of output voltage minimum by peak detection circuitV a_min_f , by itself and voltage minimum benchmarkV a_min_ref Error signal is produced after comparing work difference, then passes through voltage regulatorG v (s) produce output signalv o_Gv , the arteries and veins of converter
Rush load currenti o Filter out and obtained after DC componenti a_ref ,i a_ref Withv o_Gv It is added, as the benchmark of current inner loop, with sampling
The active filter input current arrivedi a_f Compare, its error signali e Pass through current regulator againG c (s) obtain modulated signalv o_Gc , finally willv o_Gc Switching tube is obtained by PWM circuitQ 1Control signalQ 1_dr , switching tubeQ 2 WithQ 1Complementation conducting.
Accompanying drawing 5 gives the control block diagram of control active filter output voltage peak method proposed by the invention.
It is made up of peak detection circuit, voltage regulator, PWM modulator and drive circuit.Active filter output voltage passes through
Resistor voltage divider networkR 1、R 2After obtain voltage sampling signalv a_f , then obtain output voltage peak by peak detection circuit
Value of feedbackV a_max_f , by itself and voltage peak benchmarkV a_max_ref Error signal is produced after comparing work difference, then passes through voltage-regulation
DeviceG v (s) produce output signalv o_Gv , the pulse load electric current of converteri o Filter out and obtained after DC componenti a_ref ,i a_ref Withv o_Gv It is added, as the benchmark of current inner loop, the active filter input current obtained with samplingi a_f Compare, its error letter
Numberi e Pass through current regulator againG c (s) obtain modulated signalv o_Gc , finally willv o_Gc Switching tube is obtained by PWM circuitQ 1
Control signalQ 1_dr , switching tubeQ 2 WithQ 1Complementation conducting.
The design of voltage regulator should make the bandwidth of outer voltage sufficiently low in accompanying drawing 4 and accompanying drawing 5, it is to avoid voltage regulator
The low frequency component contained in exporting brings influence to current reference, therefore the design of voltage regulator should cause cutting for outer voltage
Only frequency is much smaller than the frequency that electric current is filtered out for needed for.The design of current regulator should cause electric current loop has in low-frequency range enough
Big loop gain, to improve the ability of tracking of electric current, considers the ripple of the switching frequency time of suppression system in addition, electric current loop
Cut-off frequency should be less than 1/5 switching frequency.
Accompanying drawing 6 gives the connected mode of peak detection circuit, amplifierA 1In-phase input end and amplifierA 2Output end point
Not Wei peak detection circuit input and output end, diodeD 1Anode and negative electrode connect amplifier respectivelyA 1Anti-phase input
End and output end, diodeD 2Anode and negative electrode connect amplifier respectivelyA 1Output end and amplifierA 2In-phase input end,R p WithC p And be connected inA 2In-phase input end,R f It is connected acrossA 1Inverting input andA 2Output end.Using the control provided in accompanying drawing 4
When being formed with the control method of source filter output voltage minimum, when converter load lightens, active filter output voltage
Adaptively reduced with lightening for load, and if using the method for traditional control output voltage average value, active filter
Ripple device output voltage remains in that higher value in underloading.Therefore the method for control output voltage minimum proposed by the present invention
The switching loss of active filter switching tube when can effectively reduce underloading, improves the light-load efficiency of converter.
Using the control method of the control active filter output voltage peak provided in accompanying drawing 5, with traditional control
The method of output voltage average value is compared, when shock load after converter start, due to outer voltage voltage reference value more
It is high so that the output of Voltage loop is relatively higher, so as to obtain higher electric current loop benchmark so that active filter can be provided more
Many instantaneous pulsating power, therefore main converter output voltage falls when can effectively reduce shock load, improves converter
Dynamic response performance.
It is understood that for those of ordinary skills, can be with technique according to the invention scheme and its hair
Bright design is subject to equivalent substitution or change, and all these changes or replacement should all belong to the guarantor of appended claims of the invention
Protect scope.
Claims (5)
1. a kind of control mode of the active filter of DC link, it is characterised in that:
Active filter uses double-closed-loop control, the low frequency pulsating electric current filtered out needed for current inner loop tracking, outer voltage control
The minimum or peak of active filter output voltage, specific control mode is:
The output voltage of active filter is detected using voltage sampling circuit, the output electricity obtained with a fixed value and sampling
Pressure is subtracted each other, and its result is sent into peak detection circuit;Or directly by obtained output voltage feeding peak detection circuit of sampling;
The former is the control mode of control active filter output voltage minimum, and the latter is control active filter output voltage highest
The control mode of value;
After the output valve of peak detection circuit and active filter output voltage minimum or peak benchmark are compared,
Produce error signal feeding voltage regulator;
The electric current in active filter DC link is detected using current sampling circuit, is filtered out after its DC component, is adjusted with voltage
The output signal for saving device is added by add circuit, produces the reference signal of current inner loop;
The input current of active filter is detected, is compared with the reference signal of current inner loop, error signal feeding electricity is produced
Throttle regulator, so as to obtain modulated signal;Modulated signal is sent into PWM circuit, and switching tube is obtained by drive circuit
Drive signal.
2. a kind of control mode of the active filter of DC link according to claim 1, it is characterised in that:
Which provides a kind of active filter, and the active filter is Buck/Boost reversible transducers.
3. a kind of control mode of the active filter of DC link according to claim 2, it is characterised in that:
The Buck/Boost reversible transducers specifically include inductance, two switching tubes, storage capacitors, and one end of inductance is two-way
One input of converter, the other end of inductance connects one end of two switching tubes respectively;Wherein first switch pipe is another
Another input of end connection reversible transducer and one end of storage capacitor, the other end connection energy storage electricity of second switch pipe
The other end of appearance.
4. a kind of control mode of the active filter of DC link according to claim 3, it is characterised in that:This is active
Wave filter is connected in parallel on the main converter DC link of conventional electron circuit, for reducing the electricity of the filter capacitor needed for DC link
Capacitance.
5. a kind of control mode of the active filter of DC link according to claim 4, it is characterised in that:
When the Instantaneous input power of the main converter is higher than fluctuating output power, active filter works in Boost patterns;
When the Instantaneous input power of the main converter is less than power output, active filter works in Buck patterns.
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CN108322024A (en) * | 2017-01-18 | 2018-07-24 | 冯阳 | DC side active compensator |
CN110504621B (en) * | 2018-05-20 | 2020-11-27 | 同祥科技(北京)股份有限公司 | Ion generation unit of intelligent air purification system |
US11606849B2 (en) * | 2019-06-28 | 2023-03-14 | Texas Instruments Incorporated | Active shunt filtering |
CN110854938A (en) * | 2019-11-19 | 2020-02-28 | 深圳航天科技创新研究院 | Control device and system for reducing power pulse type load input current pulsation |
CN112993966B (en) * | 2021-04-02 | 2023-03-24 | 上海交通大学 | Active filtering method applied to direct current system |
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US6388900B1 (en) * | 2001-01-05 | 2002-05-14 | Phoenixtec Power Co., Ltd. | Constant-frequency active filter controlled by a peak current control mode |
CN1240177C (en) * | 2003-06-09 | 2006-02-01 | 清华大学 | Active power filter method with D.C. source and branch impedance decoupling control and its system |
JP5347688B2 (en) * | 2009-04-27 | 2013-11-20 | サンケン電気株式会社 | Active filter device and power conversion device |
CN101877549B (en) * | 2010-06-08 | 2012-07-25 | 南京航空航天大学 | Method for inhibiting two-stage type orthogonal inverter input current low-frequency impulse |
CN103001474B (en) * | 2012-11-29 | 2016-06-29 | 深圳Tcl新技术有限公司 | Power supply active filter and filtering method thereof |
CN103532127A (en) * | 2013-10-29 | 2014-01-22 | 哈尔滨工业大学 | Control method of DC active filter for micro DC-grid |
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