Background technology
Lead acid accumulator is to be composed in series by a plurality of single lattice batteries.The pitting that two topmost factors of analysing valve control type lead-acid accumulator battery life-span premature termination are positive grids and the excessive dehydration of electrolyte.Reduce 20% for non-maintaining type analysing valve control type lead-acid accumulator battery dehydration 10% capacity, 25% life-span of dehydration namely stops.Therefore, how such storage battery reduces fluid loss and becomes the key that prolongs the analysing valve control type lead-acid accumulator battery life-span in charging process.
The principal mode of analysing valve control type lead-acid accumulator battery dehydration is to rise to single grid voltage 2.35V in charging voltage, the anodal water decomposition side reaction precipitated oxygen that occurs, charging voltage rises to single lattice 2.42V negative pole and separates out hydrogen, namely reach and be full of 70% of piezoelectric voltage and begin precipitated oxygen from positive pole, reach and be full of 90% of voltage and begin to separate out hydrogen, charging is because the existence of oxygen passage between the both positive and negative polarity under normal circumstances, oxygen can or not formed dehydration by negative pole activator reactive absorption, even arrive the voltage value that is full of electricity, when lead acid accumulator grid internal temperature was not high, the formed pressure of oxygen and hydrogen also was not enough to bursting and goes out bonnet and form a large amount of dehydrations (only having slight dehydration).But, autumn and winter season in spring below room temperature (25 ℃), temperature is on the low side, sometimes even reach below-20 ℃ charging (freezing point of the electrolyte of lead acid accumulator is suitable for reaching below-25 ℃, what have reaches-40 ℃), this moment is because the relative thickness of both positive and negative polarity liquid, chemical reaction velocity and ionic transfer speed ratio are slower, external manifestation is that internal resistance value increases, the charging power descends greatly, positive pole is reduced to below 70% of normal room temperature, negative pole reaches below 40% especially, if do not add in the initial charge stage and thermally still to use in advance large current charge, what then can cause electrochemical polarization voltage rises and the quick increase of battery comprehensive impedance the heat (Q=I of simultaneously charging generation rapidly
2Rt) increase fast, the voltage at each grid two ends is improperly in initial charge stage fast rise.
Fig. 1 is the battery tension curve of analysing valve control type lead-acid accumulator battery when charging under room temperature (the namely 25 ℃) condition.Wherein, constant current charge stage (being the a-b section of above-mentioned curve), the speed that battery tension rises is slower, and storage battery is accepted charging also mainly in this stage, generally can accept the 70%-85% of whole charge volume.The above-mentioned constant current charge stage is adopted constant voltage charge (being the b-f section of above-mentioned curve) and floating charge (being the g-h section of above-mentioned curve) after finishing successively.
The electrolyte internal resistance increases with the reduction of temperature, reduces with the rising of temperature.Take 25 ℃ as benchmark, 10 ℃ of every reductions, then internal resistance increases 12%~15%; It is lower that temperature is tending towards, and the amplitude that internal resistance increases strengthens.This mainly is because the cause that the ratio resistance of sulfuric acid solution and viscosity increase.
If below cryogenic conditions, charge, owing to there is not preheating, to cause the cell voltage rate of climb very fast, thereby making a point of cell voltage from the described curve arrive the time that gassing voltage b orders is significantly shortened, and so that the ampere-hour number of whole charging process is less than the required ampere-hour number of battery nominal discharge capacity (110%-130% of battery capacity), namely under cryogenic conditions, adopt the first constant current of Fig. 1, rear constant voltage (is namely carried out constant voltage charge at constant voltage charge usually to gassing point, if constant current charge will cause a large amount of dehydrations all the time) charging method, will be so that battery fills insatiable hunger; Simultaneously, because the initial stage heating is large, the later stage grid internal pressure that causes charging is larger, and oxygen and hydrogen bursting and flush-out valve cap form a large amount of dehydrations, and fluid loss is larger when using constant current timing charging modes.
How solving the problem of the dehydration of charging at low temperatures, is the technical barrier of this area.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of charging device that is suitable for avoiding the analysing valve control type lead-acid accumulator battery of charging dehydration under the low temperature.
For solving the problems of the technologies described above, the invention provides a kind of charging device of analysing valve control type lead-acid accumulator battery, it comprises: the commutation supply voltage circuit; Pulse Power Magnification and transforming circuit link to each other with the power output end of this commutation supply voltage circuit, and being used for provides charge power supply to storage battery; The charging sampling loop is located between the output and storage battery of described Pulse Power Magnification and transforming circuit, for detection of charging current and voltage; Charging control circuit is used for controlling the output voltage of described Pulse Power Magnification and transforming circuit, and the charging current that records by described charging sampling loop and the potentiometer real-time internal resistance R that calculates storage battery
t
Further, if the internal resistance of the storage battery when temperature is 25 ℃ of the electrolyte in the storage battery is R
T, as the real-time internal resistance R that records storage battery
t≤ R
T, when namely the temperature of described electrolyte is not less than 25 ℃, this storage battery is carried out constant current charge, and the size of charging current is 0.1C (C is battery nominal capacity); Until the voltage of this storage battery when arriving the gassing magnitude of voltage of this storage battery, carries out constant voltage charge; When the voltage of this storage battery arrives specified saturation voltage, through floating charge complete charge after a period of time; If in the floating charge process, when recording the temperature rising of described electrolyte, stop immediately floating charge.
Further, when recording R
tR
T, when namely the temperature of described electrolyte is lower than 25 ℃, first with less than the charging current of 0.1C to one or more periods of this charge in batteries; Wherein, with less than the charging current of 0.1C to this charge in batteries during a plurality of period, the charging current of day part successively increases successively; Until R
t≤ R
T, when namely the temperature of described electrolyte is not less than 25 ℃, adopt the charging current of 0.1C to carry out constant current charge, until the voltage of this storage battery when arriving the gassing magnitude of voltage of this storage battery, carries out constant voltage charge; When the voltage of this storage battery arrives specified saturation voltage, through floating charge complete charge after a period of time.
Further, with less than the charging current of 0.1C to this charge in batteries during a plurality of period, the length of day part is consistent.
Further, the charging current within the same period big or small constant is with the convenient accumulator internal resistance size that detects.
Further, when recording described R
tDuring internal resistance when being lower than 10 ℃ greater than the temperature of described electrolyte, with less than the charging current of 0.1C to a plurality of periods of this charge in batteries, and the charging current of day part successively increases successively, to charge in batteries and preheating electrolyte, make the temperature of electrolyte arrive gradually the optimum temperature that is suitable for charging with the direct current that progressively adopts fixed size.The charging current of day part successively increases successively, can prevent the water loss problem that the too fast rising of temperature brings.
Further, described Pulse Power Magnification and transforming circuit comprise: switching tube VMOS and transformer T; The current input terminal of switching tube VMOS is connected with current output terminal and is connected primary coil with transformer T with the output of rectification circuit and is connected, and the control end of switching tube VMOS is connected with the control signal output of charging control circuit; Transformer T secondary with is connected as the input of output with the charging sampling loop, the power output end of the sampling loop that charges links to each other with storage battery; Charging control circuit is controlled charging voltage by the pulsewidth of the pwm pulse signal of the described control signal output of control.
Further, in the situation that the charging device zero load is not charged, produce pulsewidth by zero pwm pulse signal that increases gradually by charging control circuit, to survey the height of the charging voltage of charging device output under this pulse, if this charging voltage arrives the normal voltage of setting, then stop the pwm pulse width change, then control charging device and connect storage battery, and under this pwm pulse width, charge; Draw the real-time internal resistance R of storage battery with the charging current according to this moment
t
The present invention has positive effect: the preheating charging method of analysing valve control type lead-acid accumulator battery of the present invention, when low temperature, adopt little electric current to charge in batteries, until the electrolyte temperature in the storage battery is when reaching optimum value (being generally 25 ℃), adopt the first constant current of normal charging current, rear constant voltage charge, carry out at last floating charge, until be full of; The method has been avoided " the rapidly rising of electrochemical polarization voltage and the quick increase of battery comprehensive impedance, the heat (Q=I that simultaneously charging produces
2Rt) increase fast, the voltage at each grid two ends is improperly in initial charge stage fast rise " situation; thereby solved the low temperature volatile water problem that charges; guaranteed the useful life of lead acid accumulator, and so that the ampere-hour number of whole charging process satisfies the required ampere-hour number of battery nominal discharge capacity (110%-130% of battery capacity).The present invention is in the method for initial charge phase employing multistage low current charge, and is not only complete in connecing within the power scope under the positive and negative electrode low temperature condition, and the heat Q(Q=i that has utilized little electric current to produce
2Rt); so that after the grid temperature progressively raises; progressively strengthen again electric current; battery tension rises very slowly; and generating heat at the valve control battery internal temperature transfers large current charge to again to charging normal required temperature (this moment internal resistance in normal range (NR)), therefore can not produce a large amount of heats and dehydration.
Embodiment
(embodiment 1)
The preheating charging method of the analysing valve control type lead-acid accumulator battery of present embodiment comprises:
A: if the internal resistance of the storage battery when temperature is 25 ℃ of the electrolyte in the storage battery is R
T, the charging initial stage is as the real-time internal resistance R that records storage battery
t≤ R
T, when namely the temperature of described electrolyte is not less than 25 ℃, this storage battery is carried out constant current charge, and the size of charging current is 0.1C; Until the voltage of this storage battery when arriving the gassing magnitude of voltage of this storage battery, carries out constant voltage charge; When the voltage of this storage battery arrives specified saturation voltage, through floating charge complete charge after a period of time; This a period of time is 1-24 hour, and the electric current of floating charge is 0.01-0.02C; Because the floating charge electric current is less, therefore, the voltage of floating charge is generally below storage battery gassing point voltage.
In the floating charge process, when recording the temperature rising of described electrolyte, stop immediately floating charge.Specifically can measure by the charging voltage and the electric current that detect in the floating charge process: the real-time internal resistance R of storage battery
tWhether obviously diminish.
B: the charging initial stage is when recording R
tR
T, and R
tThe temperature that is in electrolyte is for less than between 25 ℃ of internal resistances during greater than 15 ℃ the time, then with the charging current of 0.05C to this storage battery constant current charge; If R
tThe temperature that is in electrolyte is then held the constant-current battery charging with the charging current of 0.04C to this for less than between 15 ℃ of internal resistances during greater than 10 ℃ the time; If that is: the temperature of electrolyte is lower, initial charging current is just less; Until R
t≤ R
T, when namely the temperature of described electrolyte is not less than 25 ℃, adopt the charging current of 0.1C to carry out constant current charge, until the voltage of storage battery when arriving the gassing magnitude of voltage of this storage battery, carries out constant voltage charge; When the voltage of this storage battery arrives specified saturation voltage, through floating charge complete charge after a period of time.
Record the real-time internal resistance R of storage battery when the charging initial stage
tIn the time of between the internal resistance when temperature that is in electrolyte is 0-10 ℃, respectively with the charging current of 0.02C, 0.04C and 0.06C to this charge in batteries each 20 minutes, or charged successively 25 minutes, 15 minutes and 10 minutes, if in this process, record R
t≤ R
T, then adopt immediately the charging current of 0.1C to carry out constant current charge.If R when this process finishes
tStill greater than R
T, then adopt the charging current of 0.06-0.08C that this storage battery is continued constant current charge, until record R
t≤ R
TThe time, adopt the charging current of 0.1C to carry out constant current charge, until the voltage of storage battery when arriving described gassing magnitude of voltage, carries out constant voltage charge; When the voltage of this storage battery arrives specified saturation voltage, through floating charge complete charge after a period of time.
See Fig. 2, the charging initial stage is as the real-time internal resistance R that records storage battery
tIn the time of between the internal resistance of the temperature that is in electrolyte during for-15 ℃ to 0 ℃, respectively with i
1=0.01C, i
2=0.02C, i
3=0.04C and i
4The charging current of=0.06C is to this charge in batteries each 30 minutes (being T=30 minute), if record R in this process (being " the charging initial stage " among Fig. 2)
t≤ R
T, then adopt immediately the charging current of 0.1C to carry out constant current charge (namely entering " charging normal the stage " among Fig. 2), until the voltage of storage battery when arriving described gassing magnitude of voltage, carries out constant voltage charge; When the voltage of this storage battery arrives specified saturation voltage, carry out floating charge complete charge after a period of time.If R when this process finishes
tStill greater than R
T, then adopt the charging current of 0.06-0.08C that this storage battery is continued constant current charge, until record R
t≤ R
T, then adopt immediately the charging current of 0.1C to carry out constant current charge, until the voltage of storage battery when arriving described gassing magnitude of voltage, carries out constant voltage charge; When the voltage of this storage battery arrives specified saturation voltage, carry out floating charge complete charge after a period of time.
The charging initial stage is as the real-time internal resistance R that records storage battery
tWhen being-15 ℃ internal resistance greater than the temperature of electrolyte, respectively with the charging current of 0.01C, 0.02C, 0.03C, 0.04C, 0.05C and 0.06C to this charge in batteries each 30 minutes, or charged successively 40 minutes, 35 minutes, 30 minutes, 28 minutes, 25 minutes and 20 minutes, that is: the temperature of electrolyte is lower, time hop count to this charge in batteries can suitably increase, and charging current slightly increases successively gradually in the day part; If in this process, record R
t≤ R
T, then adopt immediately the charging current of 0.1C to carry out constant current charge.If R when this process finishes
tStill greater than R
T, then adopt the charging current of 0.06-0.08C that this storage battery is continued constant current charge, until record R
t≤ R
T, then adopt immediately the charging current of 0.1C to carry out constant current charge, until the voltage of storage battery when arriving described gassing magnitude of voltage, carries out constant voltage charge; When the voltage of this storage battery arrives specified saturation voltage, floating charge complete charge after a period of time.
The present invention is in the method for initial charge phase employing multistage low current charge, and is not only complete in connecing within the power scope under the positive and negative electrode low temperature condition, and the heat Q(Q=i that has utilized little electric current to produce
2Rt); so that after the grid temperature progressively raises; progressively strengthen again electric current; battery tension rises very slowly; and generate heat at the valve control battery internal temperature and to transfer again large current charge to and (be generally 0.1C to charging normal required temperature (, this temperature is generally 25 ℃, internal resistance this moment is in normal range (NR)); also can adopt the arbitrary value between the 0.1C-0.25C), therefore can not produce a large amount of heats and dehydration.
When beginning to charge, adopt the direct current of fixed size to charge in batteries and preheating electrolyte, the size of the current charging current of detection just can obtain the current internal resistance (R=V/I) that is recharged storage battery in the situation of fixing PWM pulsewidth.
When beginning to charge, at first detected the size of current accumulator internal resistance by single-chip microcomputer, thereby determine the length in each little current phase time T of charging initial stage, take the 100AH valve-regulated lead-acid battery as example, if every accumulator internal resistance is lower than 8m Ω (R1), then T is zero; If every accumulator internal resistance is higher than 11 m Ω (R2), then T is 30 minutes; The 80AH valve-regulated lead-acid battery is example, and every accumulator internal resistance is lower than 10m Ω, and then T is zero; Be higher than 13 m Ω, then T is 30 minutes; The 20AH valve-regulated lead-acid battery is example, and every accumulator internal resistance is lower than 35m Ω, and then T is zero; Be higher than 48 m Ω, then T is 30 minutes etc.; Aforementioned each routine charging current i1, i2, i3, i4, I are 0.01C, 0.02C, 0.04C, 0.06C, the big or small charging current of 0.1C (C is battery nominal capacity) respectively.
Storage battery is in charging process, and it is relevant with the temperature of battery liquid with liberation of hydrogen voltage to analyse oxygen, that is:
V
Analyse oxygen35-0.004 * n * (Ta-25) (1) of=n * 2.
V
Liberation of hydrogen42-0.004 * n * (Ta-25) (2) of=n * 2.
In the formula: n is the quantity of battery grid connected in series, and Ta is the temperature of battery liquid;
Namely under 25 ℃ of environment, when n=18, analyse oxygen voltage V
Analyse oxygen=42. 3 V, liberation of hydrogen voltage V
Liberation of hydrogen=43. 56 V, and along with temperature raises and reduces, temperature reduces and increases.
The initial charge stage is fixed the fixed voltage charging that forms after the pulse duration to battery, charging voltage and electric current according to storage battery draw the real-time internal resistance of storage battery, then draw the temperature of the electrolyte in this storage battery according to the relation curve (this curve can draw by experiment) of this accumulator internal resistance value and temperature, (the gassing magnitude of voltage is the constant of storage battery when the magnitude of voltage that records storage battery reaches the gassing magnitude of voltage, can measure by experiment) time, constant current charge finishes.Then carry out constant voltage charge; When the voltage of this storage battery arrives specified saturation voltage, carry out floating charge complete charge after a period of time.
Because constant current charge determines according to actual measurement voltage to the transition of constant voltage charge, can determine the time in constant current charge stage according to the depth of discharge of different batteries like this, prevents the battery overcharge that depth of discharge is more shallow.In addition, can't reach the magnitude of voltage of regulation in order to prevent the affected battery of some quality (storage battery that had namely lost efficacy or be about to lose efficacy), the constant current charge stage arranges the longest charging interval (as: 16 hours).If arrived the longest charging interval, also do not reach the electric weight of appointment, then stop charging.
(embodiment 2)
See Fig. 3-6, use the charging device of the preheating charging method of above-mentioned analysing valve control type lead-acid accumulator battery, comprising: commutation supply voltage circuit 1, link to each other with the power output end of this commutation supply voltage circuit 1 be used for to storage battery the Pulse Power Magnification of charge power supply and transforming circuit 4 are provided, for detection of the charging sampling loop 3 of charging current and voltage be used for controlling the charging control circuit 2 of the output voltage of described Pulse Power Magnification and transforming circuit 4; Charging control circuit 2 is suitable for the real-time internal resistance R that the charging current that records by described charging sampling loop 3 and the charging voltage of fixing calculate storage battery
t, with according to R
tWith R
TMagnitude relationship, adopt corresponding charge step among the embodiment 1.
The input of rectification circuit 1 is connected with AC network, the first dc output end of rectification circuit 1 links to each other with the power input of Pulse Power Magnification and transforming circuit 4, the power output end of Pulse Power Magnification and transforming circuit 4 is connected with the power input of charging sampling loop 3, the power output end of charging sampling loop 3 is used for linking to each other with storage battery, and the voltage sampling signal output of charging sampling loop 3 links to each other with the current sampling signal input with the voltage sampling signal input of charging control circuit 2 respectively with the current sampling signal output; The pulse signal output end of charging control circuit 2 links to each other 4 with the control signal input of Pulse Power Magnification and transforming circuit 4.
See Fig. 4, charging control circuit 2 includes single-chip microcomputer IC1, integrated package of pressure-stabilizing IC2, direct current transport and placing device IC3, buffer amplifier IC4, resistance R 4~R6, R8~R10 and capacitor C 2, single-chip microcomputer IC1 is the P87LPC767 single-chip microcomputer that inside has FLASH program storage and 4 road A/D converters, the direct current transport and placing device is that model is the integrated circuit of LM358, and buffer amplifier is that model is 4050 integrated circuits; The input of integrated package of pressure-stabilizing IC2 is connected with an output of rectification circuit 1 by resistance R 4, the output of integrated package of pressure-stabilizing IC2 is connected with the power supply VCC end of single-chip microcomputer IC1, the output of integrated package of pressure-stabilizing IC2 also is connected with the positive pole of electrochemical capacitor C2, the plus earth of electrochemical capacitor C2; Resistance R 1 is connected by the positive input terminal of resistance R 5 with direct current transport and placing device IC3 as the voltage signal sampling end with the junction of transformer T, the negative input end of direct current transport and placing device IC3 is by resistance R 6 ground connection, the output of direct current transport and placing device IC3 is connected with the signal input part AD1 of single-chip microcomputer IC1 by resistance R 8, and the output of direct current transport and placing device IC3 also is connected with its negative input end by resistance R 7; The junction of resistance R 2, R3 is connected with the signal end AD0 of single-chip microcomputer IC1 as the signal sampling end; The control signal output of single-chip microcomputer IC1 is connected with the input of buffer amplifier IC4 by resistance R 9, and the output of buffer amplifier IC4 is connected with the control signal input of Pulse Power Magnification and transforming circuit 4 by resistance R 10.
Pulse Power Magnification and transforming circuit 4 comprise: switching tube VMOS and transformer T; The current input terminal of switching tube VMOS is connected with current output terminal and is connected primary coil with transformer T with the output of rectification circuit 1 and is connected, and the control end of switching tube VMOS is connected with the control signal output of charging control circuit 2; Transformer T secondary with as output with the charging sampling loop 3 input be connected.
Electricity sampling loop 3 includes rectifier diode D1, electrochemical capacitor C1, sampling resistor R1 and divider resistance R2, R3; The positive pole of described rectifier diode D1 is connected with an end of the secondary coil of transformer T, and the negative pole of rectifier diode D1 links to each other with an end of the normally opened contact of relay K A, and the other end of this normally opened contact links to each other with the positive pole of storage battery to be charged; The positive pole of electrochemical capacitor C1 is connected with the negative pole of rectifier diode D1, the minus earth of electrochemical capacitor C1; An end is connected other end ground connection with the negative pole of rectifier diode D1 after divider resistance R2, the R3 series connection; The end of sampling resistor R1 is connected with the other end of the secondary coil of transformer T, the other end of sampling resistor R1 and the minus earth of storage battery.Joint X3, X4 among Fig. 4 connects respectively the positive and negative electrode of storage battery.
Because detecting the prerequisite of accumulator internal resistance is to detect charging current under fixed voltage, and charging current, the voltage of the output of the charging device of switch power supply type are to be controlled by the pwm pulse that single-chip microcomputer produces, power supply on pulse opening and closing transformer T elementary, form elementary excitation and be coupled to again secondaryly, then form charging voltage and charging current through rectification.Because pwm pulse has passed through the links such as amplification, transformation, rectification, even the internal resistance of the storage battery that is recharged is identical, when unloaded, the pwm pulse of same duty ratio, differing produces same charging voltage and charging current surely.
Therefore, in order to detect more exactly the real-time internal resistance R of storage battery
t, the preferred version of employing is as follows:
At first in the situation that zero load is not charged, (that is: adopt relay K A to disconnect first storage battery and charging device), use single-chip microcomputer to produce pulsewidth by zero pwm pulse signal that increases gradually, to survey the height of the charging voltage of charging device output under this pulse, if this charging voltage arrives the normal voltage (the high 1-2V of voltage of this voltage ratio storage battery to be charged) of setting, then stop the pwm pulse width change, and then control relay KA connection storage battery, and under this pwm pulse width, charge; At this moment, according to charging current, can draw the real-time internal resistance R of storage battery
tThen according to R
tWith R
TMagnitude relationship, adopt corresponding charging procedure.
The method of surveying described normal voltage is: adopt relay K A to disconnect first storage battery and charging device, the unloaded output voltage of charging device is through divider resistance R2, the negative input of device IC5 as a comparison after the R3 dividing potential drop, fixed standard voltage is by 2.5V accurate reference voltage IC6 (model the is MC1403) positive input of device IC5 as a comparison, increase gradually the PWM width, the negative terminal voltage of comparator IC5 is raise gradually, until the negative input voltage of comparator IC5 is above behind the fixed standard voltage, comparator IC5 has output, so that the INT0(P1.3 of single-chip microcomputer IC1) has no progeny during fracture produces in and stop the PWM width change, IC7 and IC4 are the homophase buffer amplifiers, IC7 amplifies the high-low level of the P0.2 mouth output of single-chip microcomputer IC1 the coil of rear drive relay K A, with the break-make of control relay KA, this charging device connects or the disconnection storage battery thereby control.The method is the demarcation of initial charge voltage.After obtaining normal voltage, by described P0.2 mouth engage relay KA and detect the internal resistance that the size of electric current under this normal voltage can draw storage battery, again according to the internal resistance size, adopt corresponding charging procedure among the embodiment 1.
At first provide steady direct current to compress into capable circuit supply by electric main by rectification and filtering; Pwm pulse generation and timing control circuit are then controlled the size of initial charge current size, time length and normal charging current; Charging and temperature, electric current, voltage sampling loop are used for producing current voltage height between charging current, sampling initial charge phase ambient temperature, sampling charging current and charge period; Pulse Power Magnification and transforming circuit promote the work of high-power V metal-oxide-semiconductor after the pwm pulse of single-chip microcomputer parallel port output amplified, the switch high-frequency transformer with rectification after the high pressure transformation be charging required voltage and electric current.
The parallel port P0.1 of single-chip microcomputer IC1 sends pwm pulse, and pulse frequency is about 20KHz.Pwm pulse provides the required driving pulse frequency of Switching Power Supply pulse transformer T, make charger produce charging required pulse peak current, in the constant situation of each pwm pulse frequency, pulse duration is narrow, between arteries and veins width wide then to produce charging current little, otherwise charging current is large.Length scale between the pulsewidth arteries and veins, by the PWM generator software assignment change of P0.1 mouth, but pulse frequency is constant, namely changes the big or small size that just can control charging current between pwm pulse pulsewidth and arteries and veins.Regularly then finished by software cycles or single-chip microcomputer timer internal.Single-chip microcomputer produces the 20KHz pulse, behind the homophase Hyblid Buffer Amplifier through resistance R 9 isolation and IC4, directly driving switch pipe VMOS carries out switch on and off after resistance R 10 current limlitings, thereby will be transformed to through the high direct voltage that the alternating current 220V rectification obtains the required pulse voltage of Switching Power Supply, Switching Power Supply pulse transformer T secondary obtains the lower pulse voltage crossed through transformation, after rectifier diode D1 rectification and electrochemical capacitor C1 filtering, provide the charge in batteries required voltage.
Charging current is by the voltage of sampling resistor R1 one end (being the contact Q among Fig. 4), and the anode input as direct current transport and placing device IC3 is gathered by the A/D1 of single-chip microcomputer IC1 end after the amplification of direct current transport and placing device IC3.Voltage sample is that charging voltage is gathered by the A/D0 end of single-chip microcomputer IC1 after through divider resistance R2, R3 dividing potential drop between charge period, to obtain charging voltage value, and in time transfer constant voltage charge and floating charge to according to this charging voltage value, arrive setting voltage value after, stop whole charging process.
Single-chip microcomputer IC1 also can use inside to have the P87LPC768 chip of FLASH program storage and 4 road A/D converters and 4 road pwm pulse generators, transport and placing device IC3 can use the LM358 integrated circuit, buffer IC4, IC7 use 4050 integrated circuits, and pressurizer IC2 uses 7805 integrated circuits.
Above-described embodiment only is for example of the present invention clearly is described, and is not to be restriction to embodiments of the present invention.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here need not also can't give all execution modes exhaustive.And these belong to apparent variation or the change that spirit of the present invention extended out and still are among protection scope of the present invention.