Abstract:
A two-phase solid-state battery charger can receive input energy from a variety of sources including AC current, a battery, a DC generator, a DC-to-DC inverter, solar cells or any other compatible source of input energy. Phase I is the charge phase and phase II the discharge phase wherein a signal or current passes through a dual timing switch that controls independently two channels dividing the two phases. The dual timing switch is controlled by a logic chip or pulse width modulator. A potential charge is allowed to build up in a capacitor bank, the capacitor bank is then disconnected from the energy input source and then pulse charged at high voltage into the battery to receive the charge. The momentary disconnection of the capacitor from the input energy source allows for a free-floating potential charge in the capacitor. Once the capacitor has completed discharging the potential charge into the battery, the capacitor disconnects from the battery and re-connects to the energy source thus completing the two-phase cycle.

Description:
TECHNICAL FIELD 
     The invention relates generally to a battery pulse charger using a solid-state device and method wherein the current going to the battery is not constant. The signal or current is momentarily switch-interrupted as it flows through either the first channel, the charge phase, or the second channel, the discharge phase. This two-phase cycle alternates the signal in the two channels thereby allowing a potential charge in a capacitor to disconnect from its power source an instant before the capacitor discharges its stored potential energy into a battery for receiving the capacitor&#39;s stored energy. The capacitor then disconnects from the battery and re-connects to the power source upon completion of the discharge phase, thereby completing charge-discharge cycle. The battery pulse charger can also drive devices, such as a motor and a heating element, with pulses. 
     BACKGROUND AND PRIOR ART 
     Present day battery chargers use a constant charge current in their operation with no momentary disconnection of the signal or current as it flows either: 1) from a primary energy source to the charger; or 2) from the charger itself into a battery for receiving the charge. Some chargers are regulated to a constant current by any of several methods, while others are constant and are not regulated. There are no battery chargers currently in the art or available wherein there is a momentary signal or current disconnection between the primary energy source and the charger capacitors an instant before the capacitors discharge the stored potential energy into a battery receiving the pulse charge. Nor are there any chargers in the art that disconnect the charger from the battery receiving the charge when the charger capacitors receive energy from the primary source. The momentary current interruption allows the battery a short “rest period” and requires less energy from the primary energy source while putting more energy into the battery receiving the charge while requiring a shorter period of time. 
     SUMMARY OF THE INVENTION 
     One aspect of the invention relates to a solid-state device and method for creating a pulse current to pulse charge a battery or a bank of batteries in which a new and unique method is used to increase and preserve for a longer period of time the energy stored in the battery as compared to constant-current battery chargers. The device uses a timed pulse to create a waveform in a DC pulse to be discharged into the battery receiving the charge. 
     One embodiment of the Invention uses a means for dual switching such as a pulse width modulator (PWM), for example, a logic chip SG3524N PWM, and a means for optical coupling to a bank of high-energy capacitors to store a timed initial pulse charge. This is the charge phase, or phase I. The charged capacitor bank then discharges the stored high energy into the battery receiving the charge in timed pulses. Just prior to discharging the stored energy into the battery, the capacitor bank is momentarily disconnected from the power source, thus completing the charge phase, and thereby leaving the capacitor bank as a free-floating potential charge disconnected from the primary energy source to then be discharged into the battery. The transfer of energy from the capacitor bank to the battery completes the discharge phase, or phase II. The two-phase cycle now repeats itself. 
     This embodiment of the battery pulse charger works by transferring energy from a source, such as an AC source, to an unfiltered DC source of high voltage to be stored in a capacitor or a capacitor bank. A switching regulator is set to a timed pulse, for example, a one second pulse that is 180 degrees out of phase for each set of switching functions. The first function is to build the charge in the capacitor bank from the primary energy source; the second function is to disconnect the power source from the capacitor bank; the third function is to discharge the stored high voltage to the battery with a high voltage spike in a timed pulse, for example, a one second pulse; and the fourth function is to re-connect the capacitor bank to the primary energy source. The device operates through a two-channel on/off switching mechanism or a gauging/re-gauging function wherein the charger is disconnected from its primary energy source an instant before the pulse charger discharges the high-energy pulse into the battery to be charged. As the primary charging switch closes, the secondary discharging switch opens, and visa-versa in timed pulses to complete the two phase cycle. 
     The means for a power supply is varied with several options available as the primary energy source. For example, primary input energy may come from an AC source connected into the proper voltage (transformer); from an AC generator; from a primary input battery; from solar cells; from a DC-to-DC inverter; or from any other adaptable source of energy. If a transformer means is the source of primary input energy, it can be a standard rectifying transformer used in power supply applications or any other transformer means applicable to the desired function. For example, it can be a 120-volt to 45-volt AC step-down transformer, and the rectifier can be a full-wave bridge of 200 volts at 20 amps, which is unfiltered when connected to the output of the transformer. The positive output terminal of the bridge rectifier is connected to the drains of the parallel field-effect transistors, and the negative terminal is connected to the capacitor bank negative. 
     The Field Effect Transistor (FET) switches can be IRF260 FETs, or any other FET means to accomplish this function. All are in parallel to achieve the proper current of the pulses. Each FET may be connected through a 7-watt, 0.05-ohm resistor with a common bus connection at the source. All the FET gates may be connected through a 240-ohm resistor to a common bus. There also may be a 2 K-ohm resistor between the gates and the drain bus. 
     A transistor means, for example an MJE15024 transistor, as a driver for the gates, drives the bus and in turn, an optical coupler drives the driver transistor through the first channel. A first charging switch is used to charge the capacitor bank, which acts as a DC potential source to the battery. The capacitor bank is then disconnected from the power rectifier circuit. The pulse battery charger is then transferred to a second field effect switch through the second channel for the discharge phase. The discharge phase is driven by a transistor, the transistor driven by an optical coupler. With a second or discharge switch on, the capacitor bank potential charge is discharged into the battery to receive the charge. The battery receiving the charge is then disconnected from the pulse charger capacitor bank to repeat the cycle. The pulse charger may have any suitable source of input power including: 1) solar panels to raise the voltage to the capacitor bank; 2) a wind generator; 3) a DC-to-DC inverter; 4) an alternator; 5) an AC motor generator; 6) a static source such as a high voltage spark; and 7) other devices that can raise the potential of the capacitor bank. 
     In another embodiment of the invention, one can use the pulse charger to drive a device such as a motor or heating element with pulses of energy. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic drawing of a solid-state pulse charger according to an embodiment of the invention. 
     FIG. 2 is a schematic drawing of a conventional DC-to-DC converter that can be used to provide power to the pulse charger of FIG. 1 according to an embodiment of the invention. 
     FIG. 3 is a schematic drawing of a conventional AC power supply that can be used to provide power to the pulse charger of FIG. 1 according to an embodiment of the invention. 
     FIGS. 4A-D are schematic drawings of other conventional power supplies that can be used to provide power to the pulse charger of FIG. 1 according to an embodiment of the invention. 
     FIG. 5 is a block diagram of the solid-state pulse charger of FIG. 1 according to an embodiment of the invention. 
     FIG. 6 is a diagram of a DC motor that the pulse charger of FIG. 1 can drive according to an embodiment of the invention. 
     FIG. 7 is a diagram of a heating element that the pulse charger of FIG. 1 can drive according to an embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of the present invention is a device and method for a solid-state pulse charger that uses a stored potential charge in a capacitor bank. The solid-state pulse charger comprises a combination of elements and circuitry to capture and store available energy into a capacitor bank. The stored energy in the capacitors is then pulse charged into the battery to be charged. In one version of this embodiment, there is a first momentary disconnection between the charger and the battery receiving the charge during the charge phase of the cycle, and a second momentary disconnection between the charger and the input energy source during the discharge phase of the cycle. 
     As a starting point and an arbitrary method in describing this device and method, the flow of an electrical signal or current will be tracked from the primary input energy to final storage in the battery receiving the pulse charge. 
     FIG. 1 is a schematic drawing of the solid-state pulse charger according to an embodiment of the invention. As shown in FIG. 1, the primary input energy source to the pulse charger is a power supply  11 , examples of which are shown in FIGS. 2,  3 ,  4 A- 4 D. A 12-volt battery, as a low voltage energy source  12 , drives a dual switching means of control such as a logic chip or a pulse width modulator (PWM)  13 . Alternatively, the voltage from the power supply  11  may be converted to a voltage suitable to power the PWM  13 . The PWM  13  may be an SG3524N logic chip, and functions as an oscillator or timer to drive a 2-channel output with “on/off” switches that are connected when on to either a first optical isolator  14 , or in the alternative, to a second optical isolator  15 . The first and second optical isolators  14  and  15  may be H11D3 optical isolators. When the logic chip  13  is connected to a first channel, it is disconnected from a second channel, thus resulting in two phases of signal direction; phase I, a charge phase, and phase II, a discharge phase. When the logic chip  13  is switched to the charge phase, the signal flows to the first optical isolator  14 . From the optical isolator  14 , the signal continues its flow through a first NPN power transistor  16  that activates an N-channel MOSFET  18   a  and an N-channel MOSFET  18   b . Current flowing through the MOSFETs  18   a  and  18   b  builds up a voltage across a capacitor bank  20 , thereby completing the charge phase of the switching activity. The discharge phase begins when the logic chip  13  is switched to the second channel, with current flowing to the second optical isolator  15  and then through a second NPN power transistor  17 , which activates an N-channel MOSFET  19   a  and an N-channel MOSFET  19   b . After the logic chip  13  closes the first channel and opens the second channel, the potential charge in the capacitor bank  20  is free floating between the power supply  11 , from which the capacitor bank  20  is now disconnected, and then connected to a battery  22  to receive the charge. It is at this point in time that the potential charge in the capacitor bank  20  is discharged through a high-energy pulse into the battery  22  or, a bank (not shown) of batteries. The discharge phase is completed once the battery  22  receives the charge. The logic chip  13  then switches the second channel closed and opens the first channel thus completing the charge-discharge cycle. The cycle is repetitive with the logic chip  13  controlling the signal direction into either channel one to the capacitor bank, or to channel two to the battery  22  from the capacitor bank. The battery  22  is given a momentary rest period without a continuous current during the charge phase. 
     The component values for the described embodiment are as follows. The resistors  24 ,  26 , . . .  44   b  have the following respective values: 4.7KΩ, 4.7KΩ, 47KΩ, 330Ω, 330Ω, 2KΩ, 47Ω, 47Ω, 0.05Ω(7 W), 0.05Ω(7W), 2KΩ, 47Ω, 47Ω, 0.05Ω(7 W), and 0.05Ω(7W). The potentiometer  46  is 10KΩ, the capacitor  48  is 22 μF, and the total capacitance of the capacitor bank  20  is 0.132F. The voltage of the battery  22  is between 12-24 V, and the voltage of the power supply  11  is 24-50 V such that the supply voltage is approximately 12-15 V higher than the battery voltage. 
     Other embodiments of the pulse charger are contemplated. For example, the bipolar transistors  16  and  17  may be replaced with field-effect transistors, and the transistors  18   a ,  18   b ,  19   a , and  19   b  may be replaced with bipolar or insulated-gate bipolar (IGBT) transistors. Furthermore, one can change the component values to change the cycle time, the peak pulse voltage, the amount of charge that the capacitor bank  20  delivers to the battery  22 , etc. In addition, the pulse charger can have one or more than two transistors  18   a  and  18   b , and one or more than two transistors  19   a  and  19   b.    
     Still referring to FIG. 1, the operation of the above-discussed embodiment of the pulse charger is discussed. 
     To begin the first phase of the cycle during which the capacitor bank  20  is charged, the logic circuit  13  deactivates the isolator  15  and activates the isolator  14 . Typically, the circuit  13  is configured to deactivate the isolator  15  before or at the same time that it activates the isolator  14 , although the circuit  13  may be configured to deactivate the isolator  15  after it activates the isolator  14 . 
     Next, the activated isolator  14  generates a base current that activates the transistor  16 , which in turn generates a current that activates the transistors  18   a  and  18   b.    
     The activated transistors  18   a  and  18   b  charge the capacitors in the bank  20  to a charge voltage equal or approximately equal to the voltage of the power supply  11  less the lowest threshold voltage of the transistors  18   a  and  18   b . To begin the second phase of the cycle during which the capacitor bank  20  pulse charges the battery  22 , the logic circuit  13  deactivates the isolator  14  and activates the isolator  15 . Typically, the circuit  13  is configured to deactivate the isolator  14  before or at the same time that it activates the isolator  15 , although the circuit  13  may be configured to deactivate the isolator  14  after it activates the isolator  15 . 
     Next, the activated isolator  15  generates a base current that activates the transistor  17 , which in turn generates a current that activates the transistors  19   a  and  19   b.    
     The activated transistors  19   a  and  19   b  discharge the capacitors in the bank  20  into the battery  22  until the voltage across the bank  20  is or is approximately equal to the voltage across the battery  22  plus the lowest threshold voltage of the transistors  19   a  and  19   b . Alternatively, the circuit  13  can deactivate the isolator  15  at a time before the bank  20  reaches this level of discharge. Because the resistances of the transistors  19   a  and  19   b , the resistors  44   a  and  44   b , and the battery  22  are relatively low, the capacitors in the bank  20  discharge rather rapidly, thus delivering a pulse of current to charge the battery  22 . For example, where the pulse charger includes components having the values listed above, the bank  20  delivers a pulse of current having a duration of or approximately of 100 ms and a peak of or approximately of 250 A. 
     FIG. 2 is a schematic drawing of a conventional DC-to-DC converter  30  that can be used as the power supply  11  of FIG. 1 according to an embodiment of the invention. A DC-to-DC converter converts a low DC voltage to a higher DC voltage or vice-versa. Therefore, such a converter can convert a low voltage into a higher voltage that the pulse charger of FIG. 1 can use to charge the capacitor bank  20  (FIG.  1 ). More specifically, the converter  30  receives energy from a source  31  such as a 12-volt battery. An optical isolator sensor  33  controls an NPN power transistor  31 , which provides a current to a primary coil  36  of a power transformer  32 . A logic chip or pulse width modulator (PWM)  34  alternately switches on and off an IRF260 first N-channel MOSFET  35   a  and an IRF260 second N-channel MOFSET  35   b  such that when the MOSFET  35   a  is on the MOSFET  35   b  is off and vice-versa. Consequently, the switching MOSFETS  35   a  and  35   b  drive respective sections of the primary coil  36  to generate an output voltage across a secondary coil  38 . A full-wave bridge rectifier  39  rectifies the voltage across the secondary coil  38 , and this rectified voltage is provided to the pulse charger of FIG.  1 . Furthermore, the secondary coil  38  can be tapped to provide a lower voltage for the PWM  13  of FIG. 1 such that the DC-to-DC converter  30  can be used as both the power supply  11  and the low-voltage supply  12  of FIG.  1 . 
     FIG. 3 is a schematic drawing of an AC power supply  40  that can be used as both the power supply  11  and the power supply  12  of FIG. 1 according to an embodiment of the invention. The power input  42  to the supply  40  is 120 VAC. A first transformer  44  and full-wave rectifier  46  compose the supply  11 , and a second transformer  48 , full-wave rectifier  50 , and voltage regulator  52  compose the supply  12 . 
     FIGS. 4A-D are schematic drawings of various conventional primary energy input sources that can be used as the supply  11  and/or the supply  12  of FIG. 1 according to an embodiment of the invention. FIG. 4A is a schematic drawing of serially coupled batteries; FIG. 4B is a schematic drawing of serially coupled solar cells; FIG. 4C is a schematic drawing of an AC generator; and FIG. 4D is a schematic drawing of a DC generator. 
     FIG. 5 is a block diagram of the solid-state pulse charger of FIG. 1 according to an embodiment of the invention. Block A is the power supply  11 , which can be any suitable power supply such as those shown in FIGS. 2,  3 ,  4 A- 4 D. Block B is the power supply  12 , which can be any suitable power supply such as a 12 VDC supply or the supply shown in FIG.  3 . Block C is the PWM  13  and its peripheral components. Block D is the charge switch that includes the first optical isolator chip  14 , the first NPN power transistor  16 , the first set of two N-channel MOSFETs  18   a  and  18   b , and their peripheral resistors. Block E is the capacitor bank  20 . Block F is the discharge switch that includes the second optical isolator chip  15 , the second NPN power transistor  17 , the second set of two N-channel MOSFETs  19   a  and  19   b , and their peripheral resistors. Block G is the battery  22  that is being pulse charged. 
     A unique feature that distinguishes one embodiment of the above-described pulse charger from conventional chargers is the method charging the battery with pulses of current instead of with a continuous current. Consequently, the battery is given a reset period between pulses. 
     FIG. 6 is a diagram of a DC motor  60  that the pulse charger of FIG. 1 can drive according to an embodiment of the invention. Specifically, one can connect the motor  60  in place of the battery  22  (FIG. 1) such that the pulse charger drives the motor with pulses of current. Although one need not modify the pulse charger to drive the motor  60 , one can modify the pulse charger to make it more efficient for driving the motor. For example, one can modify the values of the resistors peripheral to the PWM  13  (FIG. 1) to vary the width and peak of the drive pulses from the capacitor bank  20  (FIG.  1 ). 
     FIG. 7 is a diagram of a heating element  70 , such as a dryer- or water-heating element, that the pulse charger of FIG. 1 can drive according to an embodiment of the invention. Specifically, one can connect the heating element  70  in place of the battery  22  (FIG. 1) such that the pulse charger drives the element with pulses of current. Although one need not modify the pulse charger to drive the element  70 , one can modify the pulse charger to make it more efficient for driving the element. For example, one can modify the values of the resistors peripheral to the PWM  13  (FIG. 1) to vary the width and peak of the drive pulses from the capacitor bank  20  (FIG.  1 ). 
     In the embodiments discussed above, specific electronic elements and components are used. However, it is known that a variety of available transistors, resistors, capacitors, transformers, timing components, optical isolators, pulse width modulators, MOSFETs, and other electronic components may be used in a variety of combinations to achieve an equivalent result. Finally, although the invention has been described with reference of particular means, materials and embodiments, it is to be understood that the invention is not limited to the particulars disclosed and extends to all equivalents within the scope of the claims.