CN103296675B - Parallel-connection direct-current power source load distribution circuit and control method thereof - Google Patents
Parallel-connection direct-current power source load distribution circuit and control method thereof Download PDFInfo
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- CN103296675B CN103296675B CN201310205206.3A CN201310205206A CN103296675B CN 103296675 B CN103296675 B CN 103296675B CN 201310205206 A CN201310205206 A CN 201310205206A CN 103296675 B CN103296675 B CN 103296675B
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Abstract
The invention belongs to the technical field of power electronics and particularly relates to a parallel-connection direct-current power source load distribution circuit among power sources when multiple direct-current switch power sources are parallelly connected to power a load and a control method of the circuit. The parallel-connection direct-current power source load distribution circuit comprises a reference current signal generating circuit, a division circuit, a bus signal generating circuit, a first load distribution bus, a second load distribution bus, a current sensor, a voltage sensor, an A/D (analog to digital) conversion circuit, a central processing unit, a driving circuit and a direct-current power source main circuit. By the parallel-connection direct-current power source load distribution circuit and the control method thereof, a control objective of reasonable load distribution according to capacity sizes can be realized, and sizes of load currents borne by the power sources can be reasonably distributed according to differences in rated capacity of each direct-current power source, so that loaded conditions of the power sources are enabled to be basically identical, the circumstances that small-capacity power sources output overlarge currents and large-capacity power sources output over-small currents are avoided, and operating efficiency, safety and reliability of the direct-current power sources in parallelly-connected operation are improved effectively.
Description
Technical field
The invention belongs to electric and electronic technical field, particularly the multiple direct-current switch power supply control method for the parallel-connection direct-current power source load distribution circuit between power supply when load is powered and this circuit in parallel.
Background technology
DC power supply (DC power supply herein and hereinafter refers in particular to direct-current switch power supply) in actual use, in order to meet the demand of power output, often adopts the scheme of multiple DC power supply parallel running.For the DC power supply of the identical parallel running of multiple capacity, certain sharing control measure must be taked, realize the mean allocation of load current, and then improve the fail safe that each power supply runs.But for the DC power supply parallel running that multiple capacity is different, also there is no good control method at present to realize the reasonable distribution of load current between each power supply.
Summary of the invention
The object of invention is to provide a kind of parallel-connection direct-current power source load distribution circuit that can realize load current and distribute between each power supply according to power supply capacity size, is of the present inventionly also the control method providing parallel-connection direct-current power source load distribution circuit.
The object of the present invention is achieved like this:
Parallel-connection direct-current power source load distribution circuit, comprise reference current signal generative circuit, division circuit, bus signal generating circuit, the first sharing of load bus, the second sharing of load bus, current sensor, voltage sensor, A/D change-over circuit, central processing unit, drive circuit and DC power supply main circuit, the output signal I of reference current signal generative circuit
refwith the DC power supply output current signal I that current sensor detection DC power supply main circuit obtains
outas the two-way input signal of division circuit, the output signal of division circuit is load coefficient k
l, wherein
for the load current that DC power supply exports, I
nfor the output-current rating of DC power supply,
a is the multiplication factor of division circuit, and bus signal generating circuit is with load coefficient k
lfor input signal, by peak load coefficient k
lmaxdeliver to the first sharing of load bus, peak load coefficient difference Δ k
lmaxdeliver to the second sharing of load bus, Δ k
l=B (k
lmax-k
l), B is the multiplication factor of operational amplification circuit; A/D change-over circuit gathers the output current I of current sensor
out, peak load coefficient k on the first sharing of load bus
lmax, peak load coefficient difference Δ k on the second sharing of load bus
lmax, division circuit load coefficient k
l, the output voltage U that obtains of voltage sensor senses DC power supply main circuit
outcarry out changing and send into central processing unit and generate drive singal and send to drive circuit to control the distribution of DC power supply main circuit adjustment power supply capacity.
Bus signal generating circuit is by two diodes, an operational amplifier, four resistance are formed: the first resistance, the 3rd resistance are connected with the negative input end of operational amplifier respectively, second resistance, the 4th resistance are connected with the positive input terminal of operational amplifier respectively, the other end of the first resistance is connected with division circuit output, the other end of the second resistance is connected with the negative pole of the first diode, and the other end of the 3rd resistance is connected with the output of operational amplifier, the other end ground connection of the 4th resistance; The positive pole of the first diode connects the output of division circuit, and negative pole is connected to the first sharing of load bus; The positive pole of the second diode connects the output of operational amplifier, and negative pole is connected to the second sharing of load bus.
The shoulder load coefficient control method of parallel-connection direct-current power source load distribution circuit, the central processing unit of each DC power supply utilizes k
lmaxwith Δ k
lmaxsignal, calculates shoulder load coefficient k
lmed, k
lmed=k
lmax-Δ k
lmax/ 2, central processing unit is by k
lmedwith the load coefficient k of own power source
lmake comparisons, if k
lbe less than k
lmed, then according to the difference of the two, increase the output voltage Setting signal of DC power supply, output voltage is raised, output current becomes large, and then load coefficient k
lbecome large, until k
lwith k
lmedbetween difference meet error requirements; If k
lbe greater than k
lmed, then according to the difference of the two, reduce the output voltage Setting signal of DC power supply, output voltage is reduced, output current reduces, and then reduces load coefficient k
l, until k
lwith k
lmedbetween difference meet error requirements.
The minimum load coefficient control method of parallel-connection direct-current power source load distribution circuit, calculates current minimum load coefficient k
lmin, k
lmin=k
lmax-Δ k
lmax, central processing unit is by k
lminwith the load coefficient k of own power source
lmake comparisons, if k
lbe greater than k
lmin, then according to the difference of the two, reduce the output voltage Setting signal of DC power supply, output voltage is reduced, output current reduces, and load coefficient diminishes until load coefficient k
lwith minimum load coefficient k
lmindifference meet sharing of load required precision.
The peak load coefficient control method of parallel-connection direct-current power source load distribution circuit, by k
lmaxwith the load coefficient k of own power source
lmake comparisons, if k
lbe less than k
lmax, then according to the difference of the two, increase the output voltage Setting signal of DC power supply, output voltage is raised, output current becomes large, and load coefficient becomes large, until the load coefficient k of power supply self
lwith peak load coefficient k
lmaxdifference meet sharing of load required precision.
Beneficial effect of the present invention is:
Existing sharing of load circuit is all under the prerequisite that power supply capacity is identical, take sharing control as target, the information of output current amplitude that what therefore these sharing of load circuit provided is all, Control System of Load Distribution when these information are the DC power supply parallel runnings that cannot be used for realizing different capabilities.And sharing of load circuit of the present invention designs for the operating mode of the DC power supply parallel running of different capabilities, this sharing of load circuit can provide and the much informations such as the closely-related load coefficient of power supply capacity for power supply, the power supply of participation sharing of load for foundation with these information, finally can realize size by measure and carry out the control objectives of reasonable share loads.During the DC power supply parallel running of multiple different capabilities, the sharing of load circuit adopting the present invention to propose and control method, can according to the difference of each DC power supply rated capacity, reasonably distribute the size of the load current that each power supply is born, the band of each power supply is made to carry situation substantially identical, the situation that power supply with small capacity output current is excessive and Large Copacity electric power outputting current is too small is avoided to occur, and then the operational efficiency of the DC power supply of effectively raising parallel running, and safety and reliability.
The shoulder load coefficient control method that the present invention proposes, is utilizing k
lmedwith k
lbetween the output voltage Setting signal of difference to DC power supply when regulating, can adoption rate integral element realize, therefore the Control System of Load Distribution of stable state can be realized, namely after sharing of load Dynamic Regulating Process terminates, if power supply and load all no longer change, then each DC power supply can maintain the stable operation always of current load condition, does not need to regulate in real time again.So this control method to have sharing of load precision high, the advantage such as effective.
The minimum load coefficient control method that the present invention proposes and peak load coefficient control method, when regulating the output voltage Setting signal of DC power supply, can only adoption rate link realize, therefore these two kinds of methods processed can only realize dynamic Control System of Load Distribution, need each DC power supply to regulate sharing of load incessantly.But compared with shoulder load coefficient control method, these two kinds of control methods are relatively simple, are easy to realize.
Accompanying drawing explanation
Fig. 1 sharing of load circuit structure diagram;
Fig. 2 bus signal generating circuit structure chart.
Embodiment
Below in conjunction with accompanying drawing, the present invention is described further:
Adopt the DC power supply of parallel-connection direct-current power source load distribution circuit proposed by the invention and control method, when multiple power sources in parallel runs, except the output-parallel of these electric power main circuits is together for except load powers, the control circuit of all these DC power supply is also linked together by two total sharing of load buses (i.e. the first sharing of load bus hereinafter and the second sharing of load bus) simultaneously.Although the capacity of the DC power supply of these parallel runnings is different, the sharing of load circuit in their control circuit is completely the same with the control method realizing sharing of load, described in specific as follows.
The parallel-connection direct-current power source load distribution circuit that the present invention proposes as shown in Figure 1, mainly comprise reference current signal generative circuit 1, division circuit 2, bus signal generating circuit 3, first sharing of load bus 4, second sharing of load bus 5, except above distinctive circuit, also should have the common current sensor of customary DC power control circuit 6, voltage sensor 7, A/D change-over circuit 8, central processing unit 9, drive circuit 10 and DC power supply main circuit 11.The present invention propose sharing of load circuit operation principle and be analyzed as follows:
The output signal of reference current signal generative circuit 1 is I
ref, I
refsize determined by formula (1).
In formula:
I
outfor the DC power supply output current signal that current sensor 6 provides, the load current that the DC power supply namely after over-current sensor 6 is changed exports;
I
lfor the load current that DC power supply exports, i.e. the input current of current sensor 6;
I
nfor the output-current rating of DC power supply.
Reference current signal I
refwith the output current signal I that current sensor 6 provides
out, respectively as the two-way input signal of division circuit 2, the output signal of division circuit 2 is load coefficient k
lits size is
In formula, A is the multiplication factor of division circuit, its size is determined by the design parameter of division circuit, suitable multiplication factor A can improve antijamming capability and the sharing of load precision of sharing of load circuit, and the multiplication factor of the division circuit in the sharing of load circuit of all parallel running DC power supply should be identical.
Formula (1) is substituted into formula (2), can obtain
Formula (3) shows, when the multiplication factor A of division circuit is constant, the size of load coefficient indicates the load current of power supply output and the ratio of rated current, i.e. the run with load situation of power supply.
Bus signal generating circuit is with load coefficient k
lfor input signal, its two-way exports and is connected with the first sharing of load bus 4 and the second sharing of load bus 5 respectively.Bus signal generating circuit concrete structure as shown in Figure 2, by diode D1, D2, operational amplifier A 1, resistance R1, R2, R3, R4 form: operational amplifier A 1 and resistance R1, R2, R3, R4 are connected into amplifying circuit; The positive pole of diode D1 connects the output of division circuit 2, is connected to the negative input end of operational amplifier A 1 by resistance R1 simultaneously, and the negative pole of diode D1 is connected to the first sharing of load bus 4, is connected to the positive input terminal of operational amplifier A 1 by resistance R2 simultaneously; The positive pole of diode D2 connects the output of operational amplifier A 1, and the negative pole of diode D2 is connected to the second sharing of load bus 5.Load coefficient signal k
lthe first sharing of load bus 4 is sent to by diode D1, because the load coefficient signal of oneself is all delivered to the first sharing of load bus 4 by diode by the DC power supply of all parallel runnings, utilize the characteristic of diode unilateral conduction known, load coefficient is only had to be that maximum power supply, the load coefficient of oneself could be sent on the first sharing of load bus 4, therefore the signal on the first sharing of load bus 4 is the maximum of the load coefficient of all DC power supply of parallel running, i.e. peak load coefficient k
lmax.Operational amplifier A 1 and resistance R1, R2, R3, R4 form operational amplification circuit, and its input signal is the voltage difference at diode D1 two ends, output signal as load coefficient difference Δ k
l, Δ k
lsize be
Δk
L=B(k
Lmax-k
L) （4）
In formula, B is the multiplication factor of operational amplification circuit, its size is determined by the design parameter of resistance, suitable multiplication factor B can improve antijamming capability and the sharing of load precision of sharing of load circuit, and the multiplication factor of the corresponding operational amplification circuit of all parallel running DC power supply should be identical.Load coefficient difference signal Δ k
lthe second sharing of load bus 5 is sent to by diode D2, because the load coefficient difference signal of oneself is all delivered to the second sharing of load bus 5 by diode by the DC power supply of all parallel runnings, utilize the characteristic of diode unilateral conduction known, load coefficient difference is only had to be that maximum power supply, could the load coefficient difference of oneself be sent on the second sharing of load bus 5, therefore and signal on two sharing of load buses 5 is the maximum of the load coefficient difference of all DC power supply of parallel running, i.e. peak load coefficient difference Δ k
lmax.
The output current signal I that current sensor 6 provides
out, the peak load coefficient k on the first sharing of load bus 4
lmaxsignal, the peak load coefficient difference Δ k on the second sharing of load bus 5
lmaxsignal, load coefficient k
lthe output voltage signal U that signal and voltage sensor 7 provide
outafter the conversion of A/D change-over circuit 8, be admitted to central processing unit 9, central processing unit 9 utilizes these information, according to concrete control method, generates drive singal, drive singal is by drive circuit 10, control the on off state of the power electronic device in DC power supply main circuit 11, and then the size of regulation output electric current, finally realize the adjustment target of load by power supply capacity reasonable distribution.
The sharing of load circuit that the present invention proposes, has unique reference current signal generative circuit, the output signal I of this circuit
refsize and the output-current rating I of power supply self
nbe directly proportional, namely utilize I
refsize embodied the difference of power supply capacity, and then provide reference frame for the reasonable distribution of load between the power supply of multiple different capabilities.
The sharing of load circuit that the present invention proposes, utilizes division circuit to generate load coefficient k
l, k
lsize directly reflected and proportionate relationship between the actual output capacity of power supply and its rated capacity if the load coefficient of all power supplys of parallel running can be made equal, also just achieved desirable Control System of Load Distribution.Therefore the load coefficient k proposed in the present invention
land generative circuit, the realization for sharing of load provides believable criterion.
Bus signal generating circuit in the sharing of load circuit that the present invention proposes, utilizes the load coefficient k of power supply self
las input signal, finally on two different sharing of load buses, define different sharing of load signals, the formation of these two sharing of load signals, the realization for Control System of Load Distribution method provides necessary basis.
The sharing of load circuit that the present invention proposes includes two sharing of load buses, and these two sharing of load buses can provide peak load coefficient k for the power supply participating in sharing of load
lmaxwith peak load coefficient difference Δ k
lmaxsignal, with these two signals for foundation, the power supply participating in sharing of load can adopt multiple control modes to realize final sharing of load.
Based on the sharing of load circuit that the present invention proposes, different Control System of Load Distribution methods can be formed, specifically comprise following three kinds of control methods.
(1) shoulder load coefficient control method.
Central processing unit 9 utilizes k
lmaxwith Δ k
lmaxsignal, calculates a shoulder load coefficient k
lmed, k
lmedcomputing formula be
k
Lmed=k
Lmax-Δk
Lmax/2 （5）
Central processing unit 9 is by k
lmedwith the load coefficient k of own power source
lmake comparisons, if k
lbe less than k
lmed, then according to the difference of the two, increase the output voltage Setting signal of DC power supply, output voltage is raised, output current becomes large, and then load coefficient k
lbecome large, until k
lwith k
lmedbetween difference meet error requirements.If k
lbe greater than k
lmed, then according to the difference of the two, reduce the output voltage Setting signal of DC power supply, output voltage is reduced, output current reduces, and then load coefficient k
lreduce, until k
lwith k
lmedbetween difference meet error requirements.Because all DC power supply all can regulate the size of self output current according to the method described above, the power supply that load coefficient is large reduces output current, the power supply that load coefficient is little increases output current, so continuing along with adjustment process, and the peak load coefficient difference Δ k on the second sharing of load bus 5
lmaxmore and more less, the peak load coefficient k that the load coefficient of each power supply can more and more level off on the first sharing of load bus 4
lmaxafter the DC power supply of all parallel runnings all completes the Dynamic Regulating Process of sharing of load, the load coefficient approximately equal of each DC power supply, according to the implication of formula (3), now achieve the adjustment object of by source nominal capacity distributing of load current between all parallel running DC power supply.
Because all DC power supply all can regulate the size of self output current according to the method described above, the power supply that load coefficient is large reduces output current, the power supply that load coefficient is little increases output current, so continuing along with adjustment process, and the peak load coefficient difference Δ k on the second sharing of load bus
lmaxmore and more less, the peak load coefficient k that the load coefficient of each power supply can more and more level off on the first sharing of load bus
lmax, after the DC power supply of all parallel runnings all completes the Dynamic Regulating Process of sharing of load, the load coefficient approximately equal of each DC power supply, namely achieves the adjustment object of by source nominal capacity distributing of load current between all parallel running DC power supply
In this control method, k
lmedwith k
lbetween difference can positive and negatively change, therefore can adoption rate integral element according to k
lmedwith k
ldifference calculate the size of the regulated quantity of output voltage Setting signal.Because Control System of Load Distribution is that adoption rate integral element realizes, therefore this control method can realize the sharing of load of stable state, namely after the DC power supply of all parallel runnings all completes the Dynamic Regulating Process of sharing of load, if load and power supply all no longer change, the sharing of load state of each then current DC power supply can be kept always, without the need to regulating in real time again.
(2) minimum load coefficient control method.
Central processing unit 9 utilizes k
lmaxwith Δ k
lmaxsignal, calculates current minimum load coefficient k
lmin, k
lmincomputing formula be
k
Lmin=k
Lmax-Δk
Lmax （6）
Central processing unit 9 is by k
lminwith the load coefficient k of own power source
lmake comparisons, if k
lbe greater than k
lmin, then according to the difference of the two, reduce the output voltage Setting signal of DC power supply, output voltage is reduced, output current reduces, and load coefficient diminishes.Due to all DC power supply, except load coefficient equals k
lmindC power supply outer (regulated quantity of the output voltage Setting signal of this power supply is zero), capital regulates the size of self output current according to the method described above, so continuing along with adjustment process, the load coefficient of each power supply more and more can level off to minimum load coefficient k
lmin, as the load coefficient k of power supply self
lwith minimum load coefficient k
lmindifference when meeting sharing of load required precision, then this power supply completes sharing of load and regulates.
Due to all DC power supply, except load coefficient equals k
lmindC power supply outer (regulated quantity of the output voltage Setting signal of this power supply is zero), capital regulates the size of self output current according to the method described above, so continuing along with adjustment process, the load coefficient of each power supply more and more can level off to minimum load coefficient k
lmin, as the load coefficient k of power supply self
lwith minimum load coefficient k
lmindifference when meeting sharing of load required precision, then this power supply completes sharing of load and regulates.
In this control method, k
lminall the time k is less than or equal to
l, therefore can only adoption rate link according to k
lminwith k
ldifference calculate the size of the regulated quantity of output voltage Setting signal.Because Control System of Load Distribution is that adoption rate link realizes, therefore this control method can only realize dynamic sharing of load, namely each DC power supply is in running, is in all the time in the dynamic process that sharing of load constantly regulates, cannot realizes the sharing of load of stable state.
(3) peak load coefficient control method.
In this control method, central processing unit 9 need utilize the peak load coefficient k on the first sharing of load bus 4
lmaxsignal.Central processing unit 9 is by k
lmaxwith the load coefficient k of own power source
lmake comparisons, if k
lbe less than k
lmax, then according to the difference of the two, increase the output voltage Setting signal of DC power supply, output voltage is raised, output current becomes large, and load coefficient becomes large.Due to all DC power supply, except load coefficient equals k
lmaxdC power supply outer (regulated quantity of the output voltage Setting signal of this power supply is zero), capital regulates the size of self output current according to the method described above, so continuing along with adjustment process, the peak load coefficient k that the load coefficient of each power supply can more and more level off on the first sharing of load bus 4
lmax, as the load coefficient k of power supply self
lwith peak load coefficient k
lmaxdifference when meeting sharing of load required precision, then this power supply completes sharing of load and regulates.
Due to all DC power supply, except load coefficient equals k
lmaxdC power supply outer (regulated quantity of the output voltage Setting signal of this power supply is zero), capital regulates the size of self output current according to the method described above, so continuing along with adjustment process, the peak load coefficient k that the load coefficient of each power supply can more and more level off on the first sharing of load bus
lmax, as the load coefficient k of power supply self
lwith peak load coefficient k
lmaxdifference when meeting sharing of load required precision, then this power supply completes sharing of load and regulates.
In this control method, k
lmaxall the time k is more than or equal to
l, therefore can only adoption rate link according to k
lmaxwith k
ldifference calculate the size of the regulated quantity of output voltage Setting signal.Because Control System of Load Distribution is that adoption rate link realizes, therefore this control method can only realize dynamic sharing of load, namely each DC power supply is in running, is in all the time in the dynamic process that sharing of load constantly regulates, cannot realizes the sharing of load of stable state.
Above three kinds of control methods, are according to current sharing of load state, regulate the output voltage Setting signal in DC power control, the output voltage Setting signal after overregulating, the output voltage signal U that recycling voltage sensor 7 provides
outwith the output current signal I that current sensor 6 provides
out, coating-forming voltage closed loop or Double closed-loop of voltage and current, the final adjustment realized the load current that DC power supply exports.
More than utilization, three kinds of control algolithms are carried out in the dynamic process of sharing of load adjustment, the load coefficient k of each DC power supply
l, peak load coefficient k on the first sharing of load bus 4
lmax, the peak load coefficient difference Δ k on the second sharing of load bus 5
lmaxall in real-time change, therefore require that A/D change-over circuit 8 has higher inversion frequency and precision, and need central processing unit 9 to have in real time, data-handling capacity fast.
When the sharing of load circuit adopting the present invention to propose and minimum load coefficient control method, by concrete control operation, flexible off-the-line between parallel running DC power supply can also be realized and flexibility controls side by side, namely exit in DC power supply or add in the process of parallel running, there is not impulse current in all DC power supply main circuits, or impulse current is very little and can control within the scope of permissible value.Concrete methods of realizing is as follows:
(1) flexible Splitting Control.If there is certain power supply to exit parallel running, then first the line between this power supply load distributor circuit and the first sharing of load bus 4 is disconnected.Now deliver to the k of this power supply A/D change-over circuit
lmaxsignal is actually the load coefficient k of this power supply self
l, and the peak load coefficient difference Δ k on the second sharing of load bus 5
lmaxnon-vanishing, according to the principle of minimum load coefficient control method, this power supply will constantly reduce its output current, its load coefficient k
lalso constantly diminish, and the output current of other DC power supply normally worked will become large gradually, namely assume responsibility for original load of the DC power supply wanting out of service, when the output current of DC power supply that will be out of service is reduced to zero, or when reaching within the scope of permissible value, disconnect the electrical link between this DC power supply main circuit and other DC power supply main circuits again, because the output current of DC power supply that now will be out of service is very little, therefore in the process disconnecting main circuit, impulse current can not be brought to other DC power supply, or impulse current can be controlled in allowed band.Finally disconnect the line between the sharing of load circuit of this DC power supply and the second sharing of load bus 5, complete flexible islanding control.
(2) flexible control method side by side.If (this power supply is called and treats and power supply) when having certain DC power supply will add parallel running, first will to treat and the sharing of load circuit of power supply and the second sharing of load bus 5 link together.Peak load coefficient difference Δ k now on the second sharing of load bus 5
lmaxnon-vanishing, concrete size, by just determining in the DC power supply of parallel running at present, treats the k that the A/D change-over circuit of also power supply collects
lmaxsignal is actually himself load coefficient k
l, owing to treating that also power supply is in Light Condition, so its output current signal I
outwith load coefficient k
lvalue be zero, according to the principle of minimum load coefficient control method, treat and the minimum load coefficient k that calculates of power supply central processing unit
lminbe less than zero, with this understanding, central processing unit blocks drive singal, and the electronic power switch device in DC power supply main circuit 11 is in cut-off state.Now will treat that the DC power supply main circuit 11 of also power supply links together with the main circuit of other parallel running DC power supply, owing to treating that the power electronic device in the DC power supply main circuit 11 of also power supply is in by state, therefore impulse current can not be produced in the process of main circuit connection.When complete until and power supply main circuit connection after, again its sharing of load circuit and the first sharing of load bus 4 are linked together, treat that also power supply, according to the signal on the first sharing of load bus 4 and the second sharing of load bus 5, regulates the output current of self, finally completes access procedure in parallel.
Feature of the present invention is
(1) during the DC power supply parallel running of multiple different capabilities, the sharing of load circuit adopting the present invention to propose and control method, can according to the difference of each DC power supply rated capacity, reasonably distribute the size of the load current that each power supply is born, the band of each power supply is made to carry situation substantially identical, the situation that power supply with small capacity output current is excessive and Large Copacity electric power outputting current is too small is avoided to occur, and then the operational efficiency of the DC power supply of effectively raising parallel running, and safety and reliability.
(2) the shoulder load coefficient control method of the present invention's proposition, is utilizing k
lmedwith k
lbetween the output voltage Setting signal of difference to DC power supply when regulating, can adoption rate integral element realize, therefore the Control System of Load Distribution of stable state can be realized, namely after sharing of load Dynamic Regulating Process terminates, if power supply and load all no longer change, then each DC power supply can maintain the stable operation always of current load condition, does not need to regulate in real time again.So this control method to have sharing of load precision high, the advantage such as effective.
(3) the present invention propose minimum load coefficient control method and peak load coefficient control method, when regulating the output voltage Setting signal of DC power supply, can only adoption rate link realize, therefore these two kinds of methods processed can only realize dynamic Control System of Load Distribution, need each DC power supply to regulate sharing of load incessantly.But compared with shoulder load coefficient control method, these two kinds of control methods are relatively simple, are easy to realize.
(4) the present invention propose sharing of load circuit and control method there is good failure tolerant ability.When some fault occurs sharing of load circuit, DC power supply still can realize sharing of load and regulate, such as:
Fault one, there is shorted to earth in the second sharing of load bus 5.Under this failure condition, the peak load coefficient difference Δ k on the second sharing of load bus 5
lmaxbe zero.If what adopt is shoulder load coefficient control method or minimum load coefficient control method, after fault occurs, according to these two kinds of controlling party ratio juris, as Δ k
lmaxwhen=0, these two kinds of control methods are transformed into peak load coefficient control method automatically, and the DC power supply of therefore all parallel runnings still can realize the adjustment of sharing of load.
Fault two, the line between certain DC power supply sharing of load circuit and the second sharing of load bus 5 disconnects.Under this failure condition, in the sharing of load circuit of the DC power supply broken down, deliver to the Δ k of A/D change-over circuit
lmaxsignal, what in fact reflect is peak load coefficient k
lmaxsignal and this power supply self load coefficient k
ldifference, according to be shoulder load coefficient control method or peak load coefficient control method, then after fault occurs, trouble power still proceeds sharing of load and regulates, and can not have a negative impact to other DC power supply of parallel connection.
(5) when the sharing of load circuit adopting the present invention to propose and minimum load coefficient control method, in the arranged side by side of DC power supply and off-the-line process, by concrete control operation, effectively can restrain the generation of the impulse current in electric power main circuit, and then improve the safety and reliability of DC power supply operation.
The first execution mode of parallel-connection direct-current power source load distribution circuit of the present invention is:
Multiple DC power supply parallel running, the control circuit part of all these power supplys is linked together by two different sharing of load buses.
Sharing of load circuit except comprising DC power supply main circuit, central processing unit, drive circuit, A/D change-over circuit, current sensor, voltage sensor, also has reference current signal generative circuit specific to it, division circuit, bus signal generating circuit, the first sharing of load bus, the second sharing of load bus etc. on hardware circuit.
DC power supply main circuit can adopt existing various direct-current switch power supply circuit, such as Buck circuit, Boost circuit, Buck-Boost circuit etc.
Current sensor can adopt existing various current sensor, such as Hall type current sensor.
Voltage sensor can adopt existing various voltage sensor, such as Hall type voltage sensor.
Existing A/D conversion chip can be adopted to be aided with input saturation circuit for A/D change-over circuit and filter circuit is formed, and also directly can adopt the A/D change-over circuit that some central processing unit inside is own.
Central processing unit can adopt digital signal processor (DSP), single-chip microcomputer, computer etc. to have Digital Signal Processing, the device of calculation function and device.
Drive circuit can adopt existing, the level signal that central processing unit exports can be converted into the various circuit of power electronic device drive singal.
First sharing of load bus and the second sharing of load bus adopt the cable with screen.
Division circuit can select the existing various circuit that can realize division function, but the division circuit multiplication factor of all parallel running DC power supply should be identical.
The mode that reference current signal generative circuit can utilize DC power supply and divider resistance to combine, by the Rational choice to direct current power source voltage value, divider resistance value, makes the output signal of circuit meet the requirement of formula (1).
Composition graphs 2, bus signal generating circuit by diode D1, D2, operational amplifier A 1, resistance R1, R2, R3, R4 form: operational amplifier A 1 and resistance R1, R2, R3, R4 are connected into amplifying circuit; The positive pole of diode D1 connects the output of division circuit, is connected to the negative input end of operational amplifier A 1 by resistance R1 simultaneously, and the negative pole of diode D1 connects the first sharing of load bus, is connected to the positive input terminal of operational amplifier A 1 by resistance R2 simultaneously; The positive pole of diode D2 connects the output of operational amplifier A 1, and the negative pole of diode D2 connects the second sharing of load bus.The diode that diode D1, D2 select forward conduction voltage drop little; Operational amplifier A 1 can select various integrated transporting discharging chip; Resistance R1, R2, R3, R4 select precision resister, and the size of resistance is chosen according to the design load of operation amplifier multiple, but this multiplication factor of all parallel running DC power supply should be identical.
Any one in Control System of Load Distribution method choice shoulder load coefficient control method, minimum load coefficient control method, peak load coefficient control method, but the control method that the DC power supply of all parallel runnings adopts should be same.
The second execution mode of parallel-connection direct-current power source load distribution circuit of the present invention is:
Adopt and existingly there is one-way conduction and do not have the circuit of electric conduction pressure drop to substitute diode in bus signal generating circuit.
Other are identical with above execution mode.
The third execution mode of parallel-connection direct-current power source load distribution circuit of the present invention is:
The form that reference current signal generative circuit adopts central processing unit and D/A conversion circuit to combine is formed, the reference current signal needed for central processing unit control D/A conversion circuit exports.
Other are identical with above execution mode.
The first execution mode based on the Control System of Load Distribution method of parallel-connection direct-current power source load distribution circuit of the present invention is shoulder load coefficient control method.
Central processing unit 9 utilizes k
lmaxwith Δ k
lmaxsignal, calculates a shoulder load coefficient k
lmed, k
lmed=k
lmax-Δ k
lmax/ 2.Central processing unit 9 is by k
lmedwith the load coefficient k of own power source
lmake comparisons, if k
lbe less than k
lmed, then according to the difference of the two, increase the output voltage Setting signal of DC power supply, output voltage is raised, output current becomes large, and then load coefficient k
lbecome large, until k
lwith k
lmedbetween difference meet error requirements.If k
lbe greater than k
lmed, then according to the difference of the two, reduce the output voltage Setting signal of DC power supply, output voltage is reduced, output current reduces, and then load coefficient k
lreduce, until k
lwith k
lmedbetween difference meet error requirements.Because all DC power supply all can regulate the size of self output current according to the method described above, the power supply that load coefficient is large reduces output current, the power supply that load coefficient is little increases output current, so continuing along with adjustment process, and the peak load coefficient difference Δ k on the second sharing of load bus 5
lmaxmore and more less, the peak load coefficient k that the load coefficient of each power supply can more and more level off on the first sharing of load bus 4
lmaxafter the DC power supply of all parallel runnings all completes the Dynamic Regulating Process of sharing of load, the load coefficient approximately equal of each DC power supply, according to the implication of formula (3), now achieve the adjustment object of by source nominal capacity distributing of load current between all parallel running DC power supply.
In this control method, k
lmedwith k
lbetween difference can positive and negatively change, therefore can adoption rate integral element according to k
lmedwith k
ldifference calculate the size of the regulated quantity of output voltage Setting signal.Because Control System of Load Distribution is that adoption rate integral element realizes, therefore this control method can realize the sharing of load of stable state, namely after the DC power supply of all parallel runnings all completes the Dynamic Regulating Process of sharing of load, if load and power supply all no longer change, the sharing of load state of each then current DC power supply can be kept always, without the need to regulating in real time again.
The second execution mode based on the Control System of Load Distribution method of parallel-connection direct-current power source load distribution circuit of the present invention is minimum load coefficient control method.
Central processing unit 9 utilizes k
lmaxwith Δ k
lmaxsignal, calculates current minimum load coefficient k
lmin, k
lmin=k
lmax-Δ k
lmax.Central processing unit 9 is by k
lminwith the load coefficient k of own power source
lmake comparisons, if k
lbe greater than k
lmin, then according to the difference of the two, reduce the output voltage Setting signal of DC power supply, output voltage is reduced, output current reduces, and load coefficient diminishes.Due to all DC power supply, except load coefficient equals k
lmindC power supply outer (regulated quantity of the output voltage Setting signal of this power supply is zero), capital regulates the size of self output current according to the method described above, so continuing along with adjustment process, the load coefficient of each power supply more and more can level off to minimum load coefficient k
lmin, as the load coefficient k of power supply self
lwith minimum load coefficient k
lmindifference when meeting sharing of load required precision, then this power supply completes sharing of load and regulates.
In this control method, k
lminall the time k is less than or equal to
l, therefore can only adoption rate link according to k
lminwith k
ldifference calculate the size of the regulated quantity of output voltage Setting signal.Because Control System of Load Distribution is that adoption rate link realizes, therefore this control method can only realize dynamic sharing of load, namely each DC power supply is in running, is in all the time in the dynamic process that sharing of load constantly regulates, cannot realizes the sharing of load of stable state.
The third execution mode based on the Control System of Load Distribution method of parallel-connection direct-current power source load distribution circuit of the present invention is peak load coefficient control method.
In this control method, central processing unit 9 need utilize the peak load coefficient k on the first sharing of load bus 4
lmaxsignal.Central processing unit 9 is by k
lmaxwith the load coefficient k of own power source
lmake comparisons, if k
lbe less than k
lmax, then according to the difference of the two, increase the output voltage Setting signal of DC power supply, output voltage is raised, output current becomes large, and load coefficient becomes large.Due to all DC power supply, except load coefficient equals k
lmaxdC power supply outer (regulated quantity of the output voltage Setting signal of this power supply is zero), capital regulates the size of self output current according to the method described above, so continuing along with adjustment process, the peak load coefficient k that the load coefficient of each power supply can more and more level off on the first sharing of load bus 4
lmax, as the load coefficient k of power supply self
lwith peak load coefficient k
lmaxdifference when meeting sharing of load required precision, then this power supply completes sharing of load and regulates.
In this control method, k
lmaxall the time k is more than or equal to
l, therefore can only adoption rate link according to k
lmaxwith k
ldifference calculate the size of the regulated quantity of output voltage Setting signal.Because Control System of Load Distribution is that adoption rate link realizes, therefore this control method can only realize dynamic sharing of load, namely each DC power supply is in running, is in all the time in the dynamic process that sharing of load constantly regulates, cannot realizes the sharing of load of stable state.
Claims (5)
1. a parallel-connection direct-current power source load distribution circuit, comprise reference current signal generative circuit (1), division circuit (2), bus signal generating circuit (3), the first sharing of load bus (4), the second sharing of load bus (5), current sensor (6), voltage sensor (7), A/D change-over circuit (8), central processing unit (9), drive circuit (10) and DC power supply main circuit (11), is characterized in that: the output signal I of reference current signal generative circuit
refwith the DC power supply output current signal I that current sensor detection DC power supply main circuit obtains
outas the two-way input signal of division circuit, the output signal of division circuit is load coefficient k
l, wherein
i
lfor the load current that DC power supply exports, I
nfor the output-current rating of DC power supply,
a is the multiplication factor of division circuit, and bus signal generating circuit is with load coefficient k
lfor input signal, by peak load coefficient k
lmaxdeliver to the first sharing of load bus, peak load coefficient difference Δ k
lmaxdeliver to the second sharing of load bus, Δ k
lmax=B (k
lmax-k
l), B is the multiplication factor of operational amplification circuit; A/D change-over circuit gathers the output current I of current sensor
out, peak load coefficient k on the first sharing of load bus
lmax, peak load coefficient difference Δ k on the second sharing of load bus
lmax, division circuit load coefficient k
l, the output voltage U that obtains of voltage sensor senses DC power supply main circuit
outcarry out changing and send into central processing unit and generate drive singal and send to drive circuit to control the distribution of DC power supply main circuit adjustment power supply capacity.
2. a kind of parallel-connection direct-current power source load distribution circuit according to claim 1, it is characterized in that: described bus signal generating circuit is by two diodes, an operational amplifier (A1), four resistance are formed: the first resistance (R1), 3rd resistance (R3) is connected with the negative input end of operational amplifier respectively, second resistance (R2), 4th resistance (R4) is connected with the positive input terminal of operational amplifier respectively, the other end of the first resistance is connected with division circuit output, the other end of the second resistance is connected with the negative pole of the first diode (D1), the other end of the 3rd resistance is connected with the output of operational amplifier, the other end ground connection of the 4th resistance, the positive pole of the first diode connects the output of division circuit, and negative pole is connected to the first sharing of load bus, the positive pole of the second diode (D2) connects the output of operational amplifier, and negative pole is connected to the second sharing of load bus.
3. the shoulder load coefficient control method of a kind of parallel-connection direct-current power source load distribution circuit according to claim 1, is characterized in that: the central processing unit of each DC power supply utilizes k
lmaxwith Δ k
lmaxsignal, calculates shoulder load coefficient k
lmed, k
lmed=k
lmax-Δ k
lmax/ 2, central processing unit is by k
lmedwith the load coefficient k of own power source
lmake comparisons, if k
lbe less than k
lmed, then according to the difference of the two, increase the output voltage Setting signal of DC power supply, output voltage is raised, output current becomes large, and then load coefficient k
lbecome large, until k
lwith k
lmedbetween difference meet error requirements; If k
lbe greater than k
lmed, then according to the difference of the two, reduce the output voltage Setting signal of DC power supply, output voltage is reduced, output current reduces, and then reduces load coefficient k
l, until k
lwith k
lmedbetween difference meet error requirements.
4. the minimum load coefficient control method of a kind of parallel-connection direct-current power source load distribution circuit according to claim 1, is characterized in that: calculate current minimum load coefficient k
lmin, k
lmin=k
lmax-Δ k
lmax, central processing unit is by k
lminwith the load coefficient k of own power source
lmake comparisons, if k
lbe greater than k
lmin, then according to the difference of the two, reduce the output voltage Setting signal of DC power supply, output voltage is reduced, output current reduces, and load coefficient diminishes until load coefficient k
lwith minimum load coefficient k
lmindifference meet sharing of load required precision.
5. the peak load coefficient control method of a kind of parallel-connection direct-current power source load distribution circuit according to claim 1, is characterized in that: by k
lmaxwith the load coefficient k of own power source
lmake comparisons, if k
lbe less than k
lmax, then according to the difference of the two, increase the output voltage Setting signal of DC power supply, output voltage is raised, output current becomes large, and load coefficient becomes large, until the load coefficient k of power supply self
lwith peak load coefficient k
lmaxdifference meet sharing of load required precision.
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| CN107040125B (en) * | 2017-04-10 | 2019-05-14 | 同济大学 | A kind of switch power supply system and its current control method |
| CN108923520B (en) * | 2018-07-13 | 2021-07-13 | 哈尔滨工程大学 | Light storage integrated power supply capable of realizing independent load distribution in series and parallel operation |
| CN112018883A (en) * | 2020-07-07 | 2020-12-01 | 普联技术有限公司 | Method, device, equipment and system for controlling multi-power-supply input of powered equipment |
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| CN102386668A (en) * | 2011-11-29 | 2012-03-21 | 合肥东耀电子有限公司 | Storage battery analog power supply device |
| CN102740540A (en) * | 2011-04-15 | 2012-10-17 | 国琏电子（上海）有限公司 | Light emitting diode driving system |
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| EP2149957B1 (en) * | 2008-07-30 | 2017-06-14 | Harman Becker Automotive Systems GmbH | Priority based power distribution arrangement |
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| CN102386668A (en) * | 2011-11-29 | 2012-03-21 | 合肥东耀电子有限公司 | Storage battery analog power supply device |
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