Background technology
The rated operational voltage of single ultracapacitor is very low, uses for it is had in the store energy field widely, and typical way is exactly with a plurality of ultracapacitor series connection in groups, thereby obtains bigger capacity.Because the difference of characterisitic parameter between each ultracapacitor, bank of super capacitors normally discharge and recharge or holding state under, voltage between the monomer can occur unbalanced, overcharges and crosses to put phenomenon and all can cause the permanent damages of ultracapacitor, and then cause the inefficacy of whole energy-storage system.Traditional voltage that discharges and recharges testing circuit monitoring monomer ultracapacitor allows maximum or minimum value if reach, and then stops so just can't making full use of resource to the discharging and recharging of whole bank of super capacitors, and has reduced power system capacity.
Monomer voltage for balanced series super capacitor bank, what the past generally used is energy consumption type voltage balance circuit, as the resistance energy-dissipating type, by detecting the voltage of each ultracapacitor, the disconnection and the closure of control and this ultracapacitor parallel resistor branch road.This voltage checking chip that only comprises, switching device is though the voltage balance circuit cost of power resistor is low, install simple and easyly, overvoltage protection can be provided, but have a lot of shortcomings, can not fully bypass charging current such as, resistance branch, the danger that makes ultracapacitor still have to overcharge; Consumption shows with heat energy at ohmically energy, because ultracapacitor quantity is many, the total amount of resistance heating can cause the instability of energy-storage system, increases the heat radiation cost simultaneously.
At present, a kind of corrective measure at resistance energy-dissipating type voltage balance circuit is arranged, as U.S. Pat 0214267A1, U.S. Pat 0077875A1 and U.S. Pat 6806686B1, the voltage balance circuit of the type is by voltage comparator, and the bleeder circuit that the resistance of two equivalences constitutes, switching tube, power resistor constitute.The bleeder circuit cross-over connection is in adjacent two ultracapacitor two ends, draw the average voltage of adjacent two ultracapacitors, as the in-phase input end of reference voltage input comparator, the connection mid point of adjacent two ultracapacitors is connected to the inverting input of comparator.By comparing the size of two input voltages, comparator generates the actuating signal of switching tube.That high resistance branch discharge along closure of voltage equates up to two ultracapacitor voltages in two ultracapacitors.The major defect of this comparator voltage equalizing circuit is: constantly remain on operating state, cause energy consumption serious, the electric voltage equalization required time is long, does not have voltage to overcharge and crosses the protection mechanism of putting.
So, be used for the deficiency that voltage balance circuit for serial connected super capacitor still exists at disclosed, need a kind of improved voltage balance circuit structure and control method, thereby reach low-power consumption, realize technical indicator such as with low cost easily.
Summary of the invention
The objective of the invention is to overcome in the prior art, in the bank of super capacitors of multiple unit series connection, voltage between the monomer ultracapacitor can't be balanced shortcoming, a kind of voltage balance circuit is provided, keeping low-cost, under the easy-to-install prerequisite, the stand-by power consumption of the energy-storage system that feasible bank of super capacitors of being connected by multiple unit constitutes is low, and the electric voltage equalization speed between the single ultracapacitor is fast.
The designed circuit of the present invention has also comprised ena-bung function, the idling consumption after finishing with minimizing ultracapacitor voltage balancing procedure.Circuit of the present invention mainly is made up of resistance, operational amplifier and switch arrays, and is simple in structure, easy for installation, is suitable for large-scale application.
The technical solution adopted in the present invention is: the principle of utilizing charge pump, realize that the electric charge between adjacent two ultracapacitors shifts, when adjacent voltage difference outside setting range, the electric charge of the ultracapacitor that voltage is high is transferred to the low ultracapacitor of voltage.Within setting range, the ena-bung function of voltage balance circuit inside is activated until the two voltage difference, and switching device stops action, and voltage balance circuit enters standby mode.
Voltage balance circuit of the present invention comprises control logic circuit and an electrochemical capacitor.Control logic circuit is made up of window comparator circuit, pulse generating circuit and switch arrays; Comprise: four switching devices, a pulse generating circuit, a low-voltage, jumbo electrochemical capacitor, two low-voltage operational amplifiers, four resistance, two diodes.Four switching devices constitute a cascade brachium pontis, be connected to adjacent two ultracapacitor two ends, four switching tubes of pulse generating circuit control alternately are connected in parallel electrochemical capacitor and two ultracapacitors with specific frequency action, finish the process that electric charge shifts.
Described window comparator circuit is by first, second bleeder circuit, first, second operational amplifier, and first, second diode is formed.First resistance and the 4th resistance constitute first bleeder circuit, and first bleeder circuit is connected in parallel between the negative pole of anodal and second ultracapacitor of first ultracapacitor, and the voltage sum of first ultracapacitor and second ultracapacitor is carried out dividing potential drop.The dividing potential drop output of first bleeder circuit is connected to the inverting input of first operational amplifier, as the Upper threshold magnitude of voltage of window comparator circuit.Second resistance and the 3rd resistance constitute second bleeder circuit, and second bleeder circuit is connected in parallel between the negative pole of anodal and second ultracapacitor of first ultracapacitor, and the voltage sum of first ultracapacitor and second ultracapacitor is carried out dividing potential drop.The dividing potential drop output of second bleeder circuit is connected to the in-phase input end of second operational amplifier, as the lower threshold voltage value of window comparator circuit.The electric current that flows through first bleeder circuit and second bleeder circuit be lower than first ultracapacitor and second ultracapacitor be full of after self leakage current.The cascade up and down of first operational amplifier and second operational amplifier.The in-phase input end of first operational amplifier is connected with the inverting input of second operational amplifier, and the negative pole with first ultracapacitor links to each other again.The positive pole of output termination first diode of first operational amplifier, the positive pole of output termination second diode of second operational amplifier.The negative pole of first diode and second diode is connected together, and as the output of window comparator circuit, is connected with the input that enables of pulse generating circuit.Switch arrays are made up of the first, second, third and the 4th controlled power switching tube of cascade up and down.First output of pulse generating circuit and second output be the first and third controlled power switching tube and second, the four controlled power switching tubes of driving switch array respectively.After described first to fourth controlled power switching tube is connected in series successively, be connected in parallel again between the negative pole of anodal and second ultracapacitor of first ultracapacitor.The connection mid point of first and second controlled power switching tube of switch arrays and the positive pole of electrochemical capacitor join, and the connection mid point of third and fourth controlled power switching tube and the negative pole of electrochemical capacitor join.The connection mid point of second and third controlled power switching tube is received the negative pole of first ultracapacitor.The difference of the voltage between first ultracapacitor and second ultracapacitor is within setting range, and voltage balance circuit quits work.Voltage difference between first ultracapacitor and second ultracapacitor exceeds setting range, voltage balance circuit makes electrochemical capacitor alternately be connected on first exit, second exit and second exit, the three terminal of voltage balance circuit by specific frequency by control logic circuit, and the electrochemical capacitor and first ultracapacitor and second ultracapacitor alternately are connected in parallel.Electrochemical capacitor adopts the electrochemical capacitor of 10v, 100uF.
The present invention only has the small part energy consumption on the conducting resistance of switching tube.And the output of the window comparator circuit of two operational amplifier compositions is connected to the Enable Pin of pulse generator, when the voltage difference of adjacent two ultracapacitors enters within the setting range, the signal pulse conductively-closed of pulse generator, switching device stop action, and electric charge shifts and stops.With respect to the energy-dissipating type voltage balance circuit, voltage balance circuit of the present invention has not had the loss on the power resistor, has saved corresponding cooling provision yet, not only saves cost, reduces loss yet, has improved the efficient of energy-storage system.In addition, voltage balance circuit balancing speed of the present invention is more a lot of soon than traditional energy-dissipating type voltage balance circuit, and all presses effect obvious.
Embodiment
Further specify the present invention below in conjunction with the drawings and specific embodiments.
As shown in Figure 1, four monomer ultracapacitors in the ultracapacitor of one group of series connection are respectively ultracapacitors 400,401,402 and 403.Voltage balance circuit 711,712 is identical with 713 internal structure, forms by a control logic circuit and an electrochemical capacitor.Wherein, voltage balance circuit 712 is made up of control logic circuit 521 and an electrochemical capacitor 511.The 4th exit 204 that just terminates to control logic circuit 521 of electrochemical capacitor 511, the negative terminal of electrochemical capacitor 511 is received the 5th exit 205 of control logic circuit 521.
The function of control logic circuit 521 is that electrochemical capacitor 511 is in parallel with adjacent two ultracapacitors of needs equilibrium respectively, thereby the electric charge of the high ultracapacitor of voltage is transferred to the low ultracapacitor of voltage.The internal structure of control logic circuit 521 can have two kinds of implementations, is respectively: the structure that comprises window comparator circuit 701, pulse generating circuit 905 and switch arrays 801 shown in Figure 2; And the structure that comprises window comparator circuit 701 and charge pump 601 shown in Figure 3.
Voltage balance circuit 711,712 and 713 correspondences are received two adjacent monomer ultracapacitors.Wherein, voltage balance circuit 712 is used for the voltage between balanced first ultracapacitor 401 and second ultracapacitor 402, and first exit 201 meets the anode a1 of first ultracapacitor 401, and used herein is the ultracapacitor that polarity is arranged.Second exit 202 be connected to adjacent two ultracapacitors 401 with 402 be connected mid point a2, the 3rd exit 203 received the negative terminal a3 of second ultracapacitor 402.Equalizing circuit 711 and 713 connection are similarly.
Voltage balance circuit 711 is used for the voltage between balanced the 4th ultracapacitor 400 and first ultracapacitor 401, and first exit 101 of voltage balance circuit 711 connects the anode of the 4th ultracapacitor 400.Second exit 102 be connected to adjacent two ultracapacitors 400 with 401 be connected mid point a1, three terminal 103 is received the negative terminal a2 of first ultracapacitor 401.
Voltage balance circuit 713 is used for the voltage between balanced second ultracapacitor 402 and the 3rd ultracapacitor 403, and first exit 301 of voltage balance circuit 713 meets the anode a2 of second ultracapacitor 402.Second exit 302 be connected to adjacent two ultracapacitors 402 with 403 be connected mid point a3, three terminal 303 is received the negative terminal of the 3rd ultracapacitor 403.
Simple installation of the present invention is easy to safeguard, only needs to connect three leads, and a voltage balance circuit just can work independently, and does not need external power source and control circuit.
Fig. 2 has specifically described a kind of embodiment of voltage balance circuit 712, and voltage balance circuit 712 internal structures mainly contain three parts: window comparator circuit 701, pulse generating circuit 905 and switch arrays 801.Switch arrays 801 are made up of controlled power switching tube a, b, c and the d of cascade about in the of four, the mid point that just terminates at switching tube a, b of an electrochemical capacitor 511, and negative terminal is connected on the mid point of switching tube c, d.When adjacent two ultracapacitors 401 and 402 the two voltage difference are outside setting range, voltage balance circuit 712 enters mode of operation, under the control of pulse generating circuit 905, four switching tube a, b, c and d are with characteristic frequency conducting according to the order of sequence, it is in parallel to make that electrochemical capacitor 511 and two adjacent ultracapacitors 401 and 402 replace, thereby electric charge is transferred to the low ultracapacitor of voltage by the high ultracapacitor of voltage.
Wherein, the conducting rule of switching tube is: the shared pulse train of switching tube a and c, output m2 output by pulse generating circuit 905, the shared pulse train of switching tube b and d, output m3 output by pulse generating circuit 905, and the pulse train interlocking of the pulse train of switching tube a, c and switching tube b, d, promptly two group pulse sequences are that logic is reciprocal.Pulse generating circuit 905 must have the measure of avoiding switching tube a, b, c and d straight-through, the situation of switching tube a, b, c and d conducting simultaneously promptly can not occur.When the voltage of first ultracapacitor 401 voltage greater than second ultracapacitor 402, when promptly the two voltage difference surpasses setting range, voltage balance circuit 712 work.Switching tube a, c conducting, switching tube b, d turn-off, the electrochemical capacitor 511 and first ultracapacitor 401 are connected in parallel, because electrochemical capacitor 511 does not have electric charge when initial, so first ultracapacitor 401 is transferred to electrochemical capacitor 511 to a part of electric charge, show as reducing of first ultracapacitor, 401 voltages, equate with the voltage of first ultracapacitor 401 until the voltage of electrochemical capacitor 511.After half period, switching tube a, c turn-off, switching tube b, d conducting, and the electrochemical capacitor 511 and second ultracapacitor 402 are connected in parallel.Because the voltage of electrochemical capacitor 511 is higher than the voltage of second ultracapacitor 402, therefore electric charge is transferred to second ultracapacitor 402 by electrochemical capacitor 511, show as the increase of second ultracapacitor, 402 voltages, equate with the voltage of second ultracapacitor 402 until electrochemical capacitor 511 voltages.Electric charge through some cycles shifts, and the voltage difference of first ultracapacitor 401 and second ultracapacitor 402 enters within the setting range, and voltage balance circuit 712 quits work.
Since this voltage balance circuit with electrochemical capacitor as the energy delivery media, different being with in the past energy-dissipating type voltage balance circuit maximum, the energy that two adjacent ultracapacitors differ is not to be consumed on the resistance, but arrives the low ultracapacitor of voltage by an electrochemical capacitor indirect branch.Though the conducting resistance of each switching tube meeting consumed energy, it is very little comparing with the energy-dissipating type voltage balance circuit.This electric voltage equalization mode that this disappears and other rises can be finished the process of electric voltage equalization at short notice, and this compares with the energy-dissipating type voltage balance circuit also is an improvement.Under the prerequisite that satisfies maximum permission conducting electric current, switch arrays 801 should use the as far as possible little switching tube of conducting resistance, include but not limited to MOSFET.
When the voltage difference of adjacent two ultracapacitors enters within the setting range, the pulse train of window comparator circuit 701 suppressor pulse generation circuit 905 makes switch arrays 801 stop conductings, further cuts down the consumption of energy.First resistance 702 and second resistance 705 constitute a bleeder circuit, and its dividing potential drop exports the inverting input of first operational amplifier 902 to, as the Upper threshold magnitude of voltage.Identical therewith, the 3rd resistance 703 and the 4th resistance 704 also constitute a bleeder circuit, and its dividing potential drop exports the in-phase input end of second operational amplifier 903 to, as the lower threshold voltage value.The in-phase input end of first operational amplifier 902 is connected with the inverting input of second operational amplifier 903, link to each other with 402 mid point 202 with adjacent two ultracapacitors 401, the voltage of mid point 202 is exactly the voltage (is reference point with end points 203) of ultracapacitor 402 again.The output of positive termination first operational amplifier 902 of diode 706; The output of positive termination second operational amplifier 903 of diode 707.Two diodes 706 link to each other with 707 negative terminal, and that receives pulse generating circuit 905 then enables input m1.
The voltage of mid point 202 is compared with the threshold voltage of window comparator circuit 701, if outside the threshold voltage scope, then voltage balance circuit work, such as, when the voltage of mid point 202 greater than the Upper threshold magnitude of voltage, then operational amplifier 902 is exported high level, diode 706 conductings, simultaneously, operational amplifier 903 output low levels, diode 707 ends, window comparator circuit 701 output high level, and the pulse that does not influence the pulse generating circuit 905 of back level produces.When the voltage of mid point 202 within the threshold voltage scope, that is, be higher than the lower threshold voltage value, be lower than the Upper threshold magnitude of voltage.Think that the voltage of adjacent two ultracapacitors 401 and 402 reaches balanced, operational amplifier 902 and 903 output low levels, diode 706 and 707 ends, window comparator circuit 701 output low levels, what this low level acted on pulse generating circuit 905 enables input m1, with the pulse signal complete closed, voltage balance circuit enters standby mode.Only just finished the task of the output of control pulse generation circuit 905 by resistance and operational amplifier.
As far as possible little for the loss that makes the electric resistance partial pressure branch road, resistance 702,703,704 and 705 should be tried one's best greatly.The electric current that guarantees the electric resistance partial pressure branch road is lower than the leakage current that ultracapacitor is full of back self.The system of selection of concrete resistance is described below: set four resistance R
702, R
703, R
704, R
705, R wherein
703=R
705, R
702=R
704, and R
705>R
702The threshold voltage scope of window comparator circuit 701 can be expressed as
So, the user can select concrete resistance value, V according to the voltage difference of the ultracapacitor of designing requirement
401, V
402The voltage of representing adjacent ultracapacitor 401 and 402 respectively.Then
V
TsThe voltage difference that expression is set.
For example: if set adjacent two ultracapacitors 401 and 402 difference range in 0.05v, V then
Ts=0.05v, wherein, V
401+ V
402=2v just can get
Figure 3 shows that another kind of implementation of the present invention, the charge pump 601 that has Enable Pin SHDN can be alternative fully with the function of the pulse generating circuit 905 of embodiment described in Fig. 2 and switch arrays 801, therefore further simplified the structure of voltage balance circuit.Charge pump 601 can be but be not limited to the chip NCP1729 of ON company.The input IN of charge pump 601 receives the anode a1 of ultracapacitor 401, and output OUT receives the negative terminal a3 of ultracapacitor 402.Adjacent two ultracapacitors 401 and 402 mid point a2 receive the GND of charge pump 601.The C+ and the C-of charge pump 601 received at the positive and negative two ends of electrolytic capacitor 511 respectively, and the output of window comparator circuit 701 is received the Enable Pin SHDN of charge pump 601.When the voltage difference of adjacent ultracapacitor 401 and 402 outside setting range, window comparator circuit 701 output high level, charge pump 601 work, its switch inside circuit makes electrolytic capacitor 511 that electric charge is transferred to the low ultracapacitor of voltage by the high ultracapacitor of voltage in two adjacent ultracapacitors with the characteristic frequency turn-on and turn-off; Voltage difference when adjacent ultracapacitor 401 and 402 enters within the setting range, window comparator circuit 701 output low levels, and charge pump 601 quits work.
According to of the present invention a kind of implementation shown in Figure 3, having completed is used for the experimental circuit of series super capacitor bank electric voltage equalization, and the parameter of use is as shown in table 1.
Table 1 experimental circuit parameter