CN1041069A - The basic circuit of regulating capacitor capacity - Google Patents

Abstract

The present invention is by a pair of capacitor, semiconductor diode and has the semiconductor device of turn-off capacity to constitute and the basic circuit of symmetry work up and down for electric power system or electrical engineering provide technology with non-mechanical approach step-less adjustment power capacitor capacity, its core.The capacity regulating scope is: heap(ed) capacity is 2 with the ratio of minimum capacity ⁿ, n=1,2,3,4 ...Both can use common constant volume value power capacitor, also can use electrolytic capacitor.The wave distortion of electric current is less.Available manually or the capacity of full electronic self-regulation capacitor, total losses are not more than 5% of capacitive reactive power.

Description

The basic circuit of regulating capacitor capacity

The invention belongs to the technology that changes the power capacitor capacity with non-mechanical approach.

As everyone knows, the power factor of raising electrical network has very important meaning to development and national economy.Power factor is not high, and basic reason is the existence owing to inductive load, and it needs certain reactive power.Improving the most frequently used method of power factor (PF) is exactly electrostatic condenser in parallel with inductive load (being arranged in user or the electric substation).For different inductive loads, must suitably select the capacitance of capacitor, capacitance is too small or excessive, all is unfavorable for the reasonable raising of power factor (PF).Thereby the technology of exploitation step-less adjustment power capacitor capacity is the work with very high economic benefit and practical value.

Though the mechanical variable capacitor in electronic technology field, the transmission of electromagnetic signal with handle in be widely used, its capacity is too little and can not set foot in electric power system.The on-mechanical formula capacity variable type capacitor that can be applicable to electric power system come into operation in Japan (seeing " electric news " magazine (day), on November 18th, 1987).This capacitor is special, and cube being directly proportional of its capacity and voltage is a kind of nonlinear capacitance device that is not easy to control.When it is applied in the fixing electric power system of voltage effective value, needs transformer isolation, and in the Circuit Fault on Secondary Transformer that is connected to special capacitor stepless voltage regulator must be set, as brush and servomechanism, transformer belongs to the ultra-large type contact type voltage regulator.The nonlinear capacitance device will produce the capacitance current wave distortion, and the capacity that when work sets up is big more, and the distortion degree is serious more.In fact, use common constant volume value power capacitor and utilize transformer, servomechanism pressure regulation, also can realize the step-less adjustment of primary side equivalent capacity, therefore do not have substantial breakthrough technically.

The objective of the invention is to overcome the shortcoming of prior art, a kind of technology that can be used for electric power system or electrical engineering, step-less adjustment power capacitor capacity is provided, requirement can be used common constant volume value power capacitor even some electrolytic capacitor, and need not the configuration isolation transformer, equipment such as big capacity alternating voltage stepless regulator.

The present invention seeks to basic circuit by step-less adjustment constant volume value condenser capacity is provided or this basic circuit should be used for realizing.The structure of basic circuit is as follows: the electrolytic capacitor C that two capacity is C ₁And C ₂By the two ends after the polarity anti-series respectively with the two-end-point X of sine ac power supply ₁And X ₃Join, two semiconductor diode D ₁And D ₂By the two ends after the polarity anti-series and two semiconductor device G with turn-off capacity ₁And G ₂By the two ends after the polarity anti-series, all respectively with X ₁And X ₃Join, and make C ₁And C ₂, D ₁And D ₂, G ₁And G ₂The series side all with a common intermediate point X ₂Join, at X ₂The C of some place ₁With D ₁Polarity mutually on the contrary with G ₁Identical, the C of polarity ₂With D ₂Polarity mutually on the contrary with G ₂Polarity identical, G ₁And G ₂Control electrode b ₁And b ₂Identical with sine ac power supply with two pulse frequencies respectively and 180 ° of phase phasic differences, pulse duration can be adjusted and the output of the trigger generator of symmetry work join above-mentioned said C from 0～(T)/2 ₁And C ₂Thereby also available common power capacitor replaces distinguishing its polarity.Test determination by reality shows, as long as the regulating impulse generator makes G ₁And G ₂The angle of flow from 0 °～90 ° variations, can allow X ₁With X ₃Capacitance between two-end-point changes from 1/2C～C and continuously, i.e. Cmax/Cmin=2, and Cmax and Cmin are respectively X here ₁With X ₃Maximum capacitor value and position of minimum capacitance between two-end-point.

Above-mentioned basic circuit also can alternatively be described: basic circuit has an intermediate point between the two ends of input coefficient, between this point and the two ends each and be connected to two antiparallel power semiconductor devices (perhaps electric semiconductor assembling device) and a capacitor.Have one can turn-off in the semiconductor device, capacitor can be power capacitor or electrolytic capacitor.The polarity of electrolytic capacitor and semiconductor device is arranged with respect to the intermediate point symmetry, and promptly the polarity from an end to intermediate point is being for just, then the other end to the polarity of intermediate point also for just; Vice versa.No matter capacitor has nonpolarityly, and power semiconductor device always makes the capacitor folk prescription to ground charging and discharge.Control the angle of flow of turn-off semiconductor device from 0 °～90 ° variations with auxiliary control circuit.

Operation principle below in conjunction with the above-mentioned basic circuit of description of drawings.

Fig. 1 is the unipolarity electrolytic capacitor.Fig. 2 (a) and (b) line map when not connecting the semiconductor device of turn-off capacity for basic circuit of the present invention.Fig. 3 (a) and (b) be respectively Fig. 2 (a) and the steady-state response figure of circuit (b) in the simple alternating current electric system.Fig. 4 is the line map of a kind of polarity connection of basic circuit of the present invention.Fig. 5 is the distortion situation map of basic circuit of the present invention current waveform in the capacity transfer process.Fig. 6～Figure 10 is respectively the line map of basic circuit Application Example 1～8 of the present invention.

(1) application of unipolarity electrolytic capacitor in simple alternating current electric power system

Capacity is the unipolarity electrolytic capacitor of C among Fig. 1, as long as both end voltage V_c＝V _o+V _oSin ω t 〉=0 just meets its working condition requirement. V in the formula_oBe the flip-flop of voltage, V_oSin ω t is alternating component. This moment current i_c＝ωCV _ocosωt。

If basic circuit is not connected to Turn-off semiconductor device, then its circuit is Fig. 2 (a) or (b). Fig. 2 (a) is respectively two kinds of connections that polarity is different with Fig. 2 (b). D among the figure₁And D₂Be semiconductor diode, C₁And C₂The constant volume value unipolarity electrolytic capacitor of C for capacitance. Method for expressing routinely represents respectively the instantaneous value of electric current, voltage and electromotive force sinusoidal quantity, for example e among the figure with lowercase i, υ and e_sInstantaneous value for the sine ac power supply electromotive force. The moment that foregoing circuit and AC power are connected, the transient process of a capacitor charging/discharging is arranged. Charging voltage $U_{C_{}}$ ${{}_2}_{}\mathrm{=U}{}_{C_3}\mathrm{=<figure-callout\; id="4"\; label="U\; C"\; filenames="891076123\_DRIMG2.png"\; state="\{\{state\}\}">U</figure-callout>}{}_{C_{}}{{}_4}_{}$ , hereinafter all be called υ_c; Charging current ic₁＝ic ₂＝ic ₃＝ic ₄, hereinafter all be called i_c For example for circuit shown in Fig. 2 (a), establish constantly t=0 just of plugged, e_s=0, then in first 1/4 cycle, C₁Charging, i

The flow direction: X₁→C ₁→D ₂→X ₃ This moment C₂The backward voltage that bears only is D₂Tube voltage drop (about 0.7 volt), harmless to electrolytic capacitor. At second 1/4 cycle, e_sDescend C from amplitude₁Discharge current can not pass through D₁, its flow direction is: C₁→X ₁→X ₃→C ₂→C ₁→X ₁→X ₃→ ..., this moment C₂Entered charged state. Work as e_sWhen being again zero, C₁And C₂On charging voltage equate and polarity is opposite that so far, two capacitors have been set up DC voltage component V_o(about 0.01 second). After this D₁、D ₂All no longer conductings, X₁And X₃Equivalent electric capacity between two-terminal is 1/2C, at this moment i_cWaveform and i the same. Fig. 2 (a) or (b) steady-state response in the simple alternating current system see Fig. 3 (a) and (b), this is confirmed by test. V among the figure_oBe e_sAmplitude, υ_cCurve be a₁，i _cCurve be b₁ This shows, press Fig. 2 (a) or connection (b), can guarantee by electrolytic capacitor C₁、C ₂Work polarity by self discharges and recharges work forever in sinusoidal ac, thereby electrolytic capacitor can be replaced the capacitor of stepless property to be used for the simple alternating current electrical network.

(2) basic principle of capacitance step-less adjustment

If at υ _cMax ≡ 2V _oCondition under (as long as e _sEffective value constant, then must satisfy this condition), manage to make Fig. 2 (a) or (b) in capacitor C ₁And C ₂The speed of discharging and recharging can accelerate υ gradually _c=0 the time interval becomes (T)/2 (T=(2 π)/(ω)), υ gradually by zero _cAnd i _cCurve respectively by Fig. 3 (a) with a (b) ₁And b ₁Be gradually varied to a ₂And b ₂, x then ₁And x ₃Equivalent electric capacity between two-terminal just can infinitely change to C by 1/2C.The circuit of realizing this point is exactly a basic circuit of the present invention, and its structure has been carried out text description in front.Now 4 its principles are described in conjunction with the accompanying drawings.Fig. 4 is the line map of a kind of polarity connection of basic circuit of the present invention, and promptly Fig. 2 (a) has connected the two semiconductor device T that have only turn-off capacity on request ₁And T ₂, T here ₁And T ₂For switch triode (this positive pole that makes two semiconductor diodes respectively with the two-end-point x of sine ac power supply ₁And x ₃The connection of joining can make control circuit in the application example that the advantage on common ground is arranged).As long as make T with trigger impulse ₁Conducting, then C ₂The charging current D that flows through ₁The T and discharging current is flowed through ₁, make T with trigger impulse ₂Conducting, then C ₁The charging current D that flows through ₂The T and discharging current is flowed through ₂, preceding half cycle D ₂And T ₂Conducting successively, second half D ₁And T ₁Conducting successively, circuit is worked up and down so symmetrically, and the waveform of i is exactly distortionless sine wave so, and the maximum of current i just in time is peaked 2 times of current i among Fig. 2 among Fig. 4, like this x among Fig. 4 ₁, x ₃The equivalent electric capacity at two ends just no longer is 1/2C but C.By adjusting b ₁, b ₂The width of the trigger impulse at two ends makes T ₁And T ₂ON time change from 0～T/2, just can realize making x ₁, x ₃The equivalent electric capacity at two ends infinitely changes to little from 1/2C.In this adjustment process, the wave distortion situation of current i is seen Fig. 5, and Cmin is x among the figure ₁, x ₃The minimum capacity at two ends (being 1/2C).From this figure as can be known, the total effective value of each harmonic is 32.5% with the maximum of the ratio of first-harmonic effective value; The triple-frequency harmonics amplitude is 30.5% with the maximum of the ratio of fundamental voltage amplitude.In three-phase system, triple harmonic current is not appeared in the line current, the total effective value of each harmonic this moment is 17.6% with the maximum of the ratio of first-harmonic effective value; The amplitude of quintuple harmonics is 15.5% with the maximum of the ratio of fundamental voltage amplitude, and the seventh harmonic amplitude is 11.5% with the maximum of the ratio of fundamental voltage amplitude, and visible wave distortion is less.

(3) operating mode of each components and parts

If the maximum effective value of current i is I among Fig. 4 _c, then the effective value of every maximum charging and discharging currents of capacitor is I _c/ 2, the electric field strength between every capacitor both positive and negative polarity is only made size variation and nondirectional change; The maximum effective value of electric current of diode and triode of flowing through is (I _C)/2, maximum average current are 0.225I _c; The maximum reverse pressure drop of diode is e _sMaximum, the reverse pressure drop of triode is less than 1 volt.Therefore the general semiconductor device can be competent at a job, and can be used for the simple alternating current electrical network to unipolarity, low-loss, resistant to elevated temperatures electrolytic capacitor.

Compare with prior art, advantage of the present invention and good effect are:

1. the scope of application is extensive, and it both can be used as power device, also can be used as control device.Nonlinear reactance device (as autotransducer).In electric power system, be widely used, but because of it is a perceptual device after all, and the most of loads in the power frequency, intermediate frequency electric power system are inductive, so its range of application still is restricted.The present invention has developed the antithesis device-stepless adjustable condenser of nonlinear reactance device, so its range of application in simple alternating current electric power system will be wider than nonlinear reactance device.

2. opened up new application approach for such two class capacitors: a class is common constant volume value power capacitor, and another kind of is electrolysis-type unipolarity and the big capacitor (because of being Technology of stepless, can in time regulate with the capacity error) of appearance value error.Especially the aluminium electrolytic capacitor of producing for the Germany that can use in AC electric power systems (seeing " Siemons Compononts ", Vol.22,1987,1) provides application approach.

3. the stepless adjustable extent of condenser capacity can be bigger, also can be less, can adjust according to actual needs and easily.

4. up to the present, do not see report as yet, so the present invention has opened up new application market for power semiconductor device with power semiconductor device regulating capacitor capacity.

5. the present invention is used for simple alternating current electric power system, and the waveform distortion of its capacitance current comes the little of capacity transfer than the nonlinear characteristic that relies on capacitor.Its main cause is that the former the waveform maximum distortion degree and the capacitance of setting have nothing to do, the latter then is that the capacity of setting up is big more, and waveform maximum distortion degree is also big more, and is high more as the transformer original edge voltage, magnetic circuit is saturated more, and then the wave distortion of exciting curent is serious more the same.

Equipment such as 6 can not add as isolating transformer, big capacity alternating voltage stepless regulator and directly use.

7. it is simple to regulate circuit, and the capacitor of use, semiconductor components and devices etc. are common specification, so cost is low.

8. can realize that full electronic changes capacitance automatically, not need to realize the servomechanism of mechanical displacement, and make the reaction speed of device very fast therefrom, whole device.Can accomplish that contactless, noiseless, volume are little.

The principle of basic circuit of the present invention is unique, but it is more to practice the technological approaches of basic circuit of the present invention, and along with adjustable range, operating frequency, the application scenario difference of capacitance, the application implementation scheme of basic circuit can be slightly different.Provide 8 application examples of the present invention below in conjunction with accompanying drawing.

Example 1. is seen Fig. 6, and 1a and 1b are switch triodes, and 2a and 2b are common rectifier diodes, and 3a and 3b are the constant volume value unipolarity electrolytic capacitors (also available common power capacitor replaces) that capacitance is C.The 4th, capacity is the isolating transformer below 1 volt-ampere, and it works to isolate and provide synchronizing signal.In the frame of broken lines 5 this example and the line map of the major control module of example subsequently.The control signal of terminal B is from the control signal to electric capacitance change, and its form is and Fig. 6 variable voltage signal altogether.When manually controlling, the B point can be connected on the adjustable DC voltage source, as utilizes variable resistor dividing potential drop or silicon controlled rectifier voltage source etc.Because the B point only needs voltage signal, only need the electric current of microampere order, thereby this variable voltage signal obtains easily.The minimum voltage of voltage signal source is zero volt, and maximum voltage value is slightly larger than the maximum of the secondary voltage to earth of transformer 4.E among the figure _cBe the dc supply of operational amplifier, e _sBe sinusoidal ac potential source, T ₃And T ₄Be switch triode, A ₁And A ₂For being operated in the operational amplifier under the comparator state.If e _sPositive half cycle the time, υ _X5〉=0, during this period, work as υ _X5＞V _BThe time, A ₂The output positive pulse, T ₄Conducting, the base current of 1b occurs, and works as x ₃To x ₂The voltage of end is timing, 1b conducting and the discharge path of the sine ac power supply of flowing through is provided for 3a.υ _X5＞V _BThe time of being experienced is long more, and flow through time of 1b of the discharge stream of 3a is also just long more, and vice versa.And work as υ _X5＜V _BThe time, T ₄End, 1b turn-offs.A ₁, T ₃Same as described above with the operation principle of 1a, just on phase place, differ 180 °.Change the speed that discharges and recharges that current potential that B orders can change capacitor like this, make x ₁, x ₃The equivalent capacity at two ends is with V _BStepless variation and change continuously, excursion is that 1/2C is to C.Frame of broken lines 6a and 6b represent that components and parts can replace with corresponding semiconductor combinations device in the frame among the figure.

Example 2. is seen Fig. 7, interior slightly variant of frame of broken lines 6 among the control module circuit in the frame of broken lines 7 and example 1 Fig. 6, but operation principle is identical.8a and 8b are turn-off thyristor, and components and parts can replace with corresponding electric semiconductor assembling device in frame of broken lines 9 and the 10 expression frames.A ₃And A ₄For being operated in the operational amplifier under the comparator state, all the other components and parts are identical with the components and parts of same numeral among Fig. 6.

Slightly than the height of example 2, the other technologies feature is identical for the operating frequency of example 1 and efficient.The increment of capacitance and V _BValue be approximated to inverse ratio.If change signal into the isosceles triangle wave of same frequency, the then increment of capacitance and V by sine wave _BValue be inversely proportional to.

Example 3 and 4. is seen Fig. 8, E _sBe reference power supply (direct current) e among its value and Fig. 6 _sEffective value become a fixing ratio.11a, the capacitance of 11b is C.E in the frame of broken lines 12 is aforesaid stepless variable voltage signal circuit illustraton of model.Same label terminal B, the x among Fig. 6 and Fig. 8 ₁, x ₂, x ₃Link to each other, just constitute example 3 of the present invention; Same label terminal B, the x among Fig. 7 and Fig. 8 ₁, x ₂, x ₃Link to each other, then constitute example 4.The step-less adjustment scope of example 3 and 4 capacitances is 1/2C～2C, that is:

Cmax/Cmin＝4。

Among Fig. 8 (a), the maximum Emax of E is slightly larger than the peaked twice of secondary voltage to earth of transformer 4 among Fig. 6 or Fig. 7, E _sBe 1/2 of Emax.The effect of circuit shown in Fig. 8 (a) is: when E from 2E _sWhen changing to Es, V _BChange to zero from Es, this interval x ₁, x ₃The capacitance of end changes to C from 1/2C.Contactor J action when E is slightly less than Es, 11a is in parallel with 3a, and 11b is in parallel with 3b, V _BBe slightly less than Es, and from then on follow E and diminish.After the J action, though newly dropped into 11a and 11b, because triode 1a and 1b, so the neither conducting of diode 2a and 2b is x ₁, x ₃The capacitance at two ends remains C(and J is failure to actuate, x when the triode diode current flow time is T/4 ₁, x ₃Capacitance between two ends equates).When E continues to diminish until zero volt, x ₁, x ₃Between capacitance change to 2C from C.

Example 5 and 6. is seen Fig. 9, and the capacity of 13a and 13b equates that with the capacity of 3a, 3b among Fig. 6, Fig. 7 the capacity of 14a, 14b is 13a or 13b 2 times.Es is identical with Fig. 8's, and the E in the frame of broken lines 12 still is a stepless variable voltage signal circuit model.With same label terminal B, the x among Fig. 6 and Fig. 9 ₁～x ₅Link to each other, constitute the 5th example; With same label terminal B, the x among Fig. 7 and Fig. 9 ₁～x ₅Link to each other, constitute the 6th example.The step-less adjustment scope of example 5 and 6 capacitances is 1/2C～4C, i.e. Cmax/Cmin=8.

Es=2V among Fig. 9 _F(V _FThe voltage to earth of ordering for F), the maximum of E is 3V _F, Vx ₄Maximum be slightly less than V _F, and output voltage V _BAlways lie prostrate V zero _FThis scope and changing.1J, 2J are contactor.Controlled thyristor 19a, 19b and 21a, 21b are e _sTrigger when being about zero, thereby the impact when dropping into 13a, 13b or dropping into 14a, 14b exists hardly.And after crystal diode 20a, 20b and 22a, 22b can guarantee to excise 13a, 13b or 14a, 14b, in the time of four/one-period, discharge into no-voltage, thereby do not need discharge line.When dropping into, this release mutual capacitance produces the technological means of impacting the road that do not need to discharge, be to connect with mutual capacitance after adopting a thyristor and uncontrollable diode inverse parallel, make flow through the respectively circuit of thyristor and diode of capacitor charge and discharge electric current.Example 5 and 6 characteristics are that reaction speed is fast.

Example 7 and 8. is seen Figure 10,15a and 15b, and 16a and 16b, 17a and 17b, the capacity of 18a and 18b is respectively C, 2C, 4C, 8C.Still stepless variable voltage signal circuit model in the frame of broken lines 12.1J～4J is D.C. contactor, and 1C～4C is A.C. contactor, E _sWith aforesaid identical.With the same label end B among Fig. 6 and Figure 10, x ₁～x ₃Link to each other, constitute example 7; With the same label end B among Fig. 7 and Figure 10, x ₁～x ₃Link to each other, constitute and implement 8.The step-less adjustment scope of example 7 and 8 capacitances is 1/2C～16C, i.e. Cmax/Cmin=32.

The maximum of E is 5 times of Vc among Figure 10 ₁(Vc ₁Be c ₁The voltage to earth of point), E _sValue be 4 times of Vc ₁

According to the design of Fig. 6 to Figure 10, this professional those of ordinary skill constitutes the different operating frequency easily, different electric pressures, different application occasion, the various embodiment of different electric capacitance change scopes.For example, can accomplish Cmax/Cmin=2 for the capacity transfer scope ⁿ, n=1,2,3 ...

Claims (4)

1, a kind of basic circuit of regulating capacitor capacity is used for electric power system or electrical engineering, it is characterized in that: the electrolytic capacitor C that two capacity is C ₁And C ₂By the two ends after the polarity anti-series respectively with the two-end-point x of sine ac power supply ₁And x ₃Join, two semiconductor diode D ₁And D ₂By the two ends after the polarity anti-series, and two semiconductor device G with turn-off capacity ₁And G ₂Press the two ends after the utmost point anti-series, all respectively with x ₁And x ₃Join, and make C ₁And C ₂, D ₁And D ₂, G ₁And G ₂The series side all with a common intermediate point x ₂Join, at x ₂The C of some place ₁With D ₁Polarity mutually on the contrary with G ₁Polarity identical, C ₂With D ₂Polarity mutually on the contrary with G ₂Polarity identical, G ₁And G ₂Control electrode b ₁And b ₂180 ° of identical with sine ac power supply with two pulse frequencies respectively and phase phasic differences, pulse duration can be adjusted and the output of the pulse generator of symmetry work join above-mentioned said C from 0～T/2 ₁And C ₂Thereby also available common power capacitor replaces distinguishing its polarity.

2, the basic circuit of regulating capacitor capacity as claimed in claim 1 is characterized in that: two semiconductor diode D ₁And D ₂Positive pole respectively with the two-end-point x of sine ac power supply ₁And x ₃Join.

3, the basic circuit of regulating capacitor capacity as claimed in claim 2 is connected with mutual capacitance after it is characterized in that adopting a thyristor and uncontrollable diode inverse parallel, makes the charging and discharging currents of capacitor flow through respectively thyristor and diode.

4, the basic circuit of regulating capacitor capacity as claimed in claim 2 is characterized in that wherein D ₁And G ₁, D ₂And G ₂Can adopt corresponding electric semiconductor assembling device to replace.

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