Patent Application
20070220773
1. Field of the Invention
The present invention relates in general to portable energy storage devices such as, for example only, heat generating elements. In particular, the invention relates to a hair curler, a hair straightener, a flat clothes iron, or any other such device for storing energy comprising a rotating flywheel, a light source, or the like. The energy storage device uses an external power source to bring the device to a desired operating condition thereby conserving internal battery power and to simultaneously charge internal batteries during the time that the device is placed in a base unit. When the device is removed from the base unit, the internally located batteries automatically provide energy to the heating element to make the device portable. A Pulse Time Modulation circuit regulates the battery power output at a level sufficient only to replace power losses in the device, again extending the life of the internal batteries.
2. Description of the Prior Art
In commonly assigned, copending patent application Ser. No. 11/094,000, entitled Portable Energy Consuming Device, and incorporated herein by reference in its entirety, there is disclosed an energy storage device such as a hair curler, a flat iron, a light source, or a rotating mass.
The device sits in a base unit when not in use. The base unit is connected to an external power source for applying power to the device to pre-energize the device to a predetermined level. For example, if the device is a curling iron, the external power, when the device is placed in the base unit, preheats the heating element to a predetermined temperature. The heating element of the device may be an AC heating element (in which case the external power source is a conventional wall socket providing AC power for preheating the device) or a DC heating element (in which case the external AC power source is rectified to a DC voltage that is used for preheating the device).
If an AC heating element is provided for preheating the device, a second DC heating element is located adjacent the AC heating element (which also preheats the DC heating element) and when the device is removed from the base unit, an internal DC power source is automatically connected to the DC heating element to maintain the existing preheat value.
Obviously the use of an external power source to pre-energize the device to a predetermined level (e.g. a predetermined temperature) extends the life of the internal batteries since the battery power is not expended in pre-energizing the device to the predetermined level. Such a system is disclosed in U.S. Pat. No. 6,664,516 which uses a PTC (positive temperature coefficient) thermistor that enables a high current to be provided to the heating element initially. However, as the time of application of the voltage increases, the electric current will decrease sharply until it reaches a low level whereupon it will remain relatively constant. Thus, power applied to the load is regulated by the PTC element serving as the load.
A device is disclosed in U.S. Pat. No. 4,857,702 that utilizes an external power source to recharge the internal batteries. This device requires the use of an AC wall socket plug that is pivotally mounted in the side of the device handle. When the plug is pivoted outwardly, it forms connections internally of the device to recharge the batteries. If the device is unplugged from the wall socket and the AC wall socket plug is pivoted inwardly of the body or handle, it provides internal connections that allow the charged batteries to heat the heating element. It will be seen that the battery cannot be charged while the heating element is being heated and the heating element cannot be heated while the battery is being charged.
As stated above, these devices prolong the life of the internal batteries by preheating the element with an external power source and, thus, saving the battery energy for simply supplying power to the heating element to maintain its heat.
As recognized in copending, commonly assigned, U.S. patent application Ser. No. 11/094,729, incorporated herein in its entirety by reference, an energy consuming device operates according to the well known equation
PO=PIN−PL (1)
where PO=Power output, PIN=Power input, and PL=Power losses associated with the device.
However, if the device is an energy storage device, when the energy storage device reaches its operating condition (e.g. desired temperature, rotational speed, momentum, and the like), residual power, PR becomes a factor in equation (1) above which becomes
Po=Pin−PL+PR (2)
where PR=Residual Power and where “Residual Power” or “Residual Energy” is defined as “residual heat”, “rotational energy”, “mass momentum”, “linear motion”, “dynamic energy”, or any other term representing “potential energy” or “kinetic energy” in a device that is stored by the applied power. The residual power or a energy can be used to conserve energy used by such a device.
It can be seen in equation (2) that if PIN is reduced to equal PL, then the residual power, PR, is sufficient to maintain the desired output power, PO. If the residual power, PR, is small, such as with a small electrical motor, because of low inertia and mass, only a small amount of energy can be conserved.
In particular, the invention relates to a method and apparatus for providing a portable energy storage and consuming device that has an external power source to cause the device to reach its desired operating condition (set forth above), an internal power supply for supplying power to the load of the portable device only when the external power source is disconnected, and a pulse time modulation device coupled between the internal battery or energy cell and the energy consuming and storing load to obtain a desired output power, PO, from the electrical load by simply supplying sufficient pulse time modulated energy, PIN, to the load to replace only load losses, PL, and to maintain only the residual power, PR, thus maintaining the desired power output, PO, and thereby conserving input energy, PIN, that would otherwise be wasted.
It is known to manually adjust input power to maintain a desired load. A circuit that is manually controlled to set a desired temperature is disclosed in commonly assigned U.S. Pat. No. 6,449,870 and U.S. Pat. No. 6,718,651.
Also, there are soldering devices that have a control circuit that shuts the power to the tip OFF when a certain temperature is reached and then turns the power ON again when the temperature falls below a desired temperature level. While it is done automatically, the power is not continuously regulated by a circuit that automatically varies the rate of pulsed (Pulse Time Modulation) power applied to the load to continuously maintain a desired operating condition such as temperature.
For a rotating energy storage device, such as a wheel, motor, and the like, when input power to the rotating device is removed, the motor or wheel continues to rotate by means of stored energy until frictional energy (power losses) completely expends the stored energy (residual power).
One circuit for manually providing input power, PIN, in an amount equal to the power losses, PL, is disclosed in commonly assigned U.S. patent application Ser. No. 11/055,235, incorporated herein by reference in its entirety.
It would be very desirable to have an improved device that provides continuous externally supplied electrical input power to an electrical energy storage device until the device reached its selected desired operating condition as long as the device is placed on a base unit during which time the internal batteries are charged and recharged. After the desired operating condition is reached (e.g. desired temperature), the device can be made portable by removing the device from its base by which action internally located batteries are automatically coupled to a heating element to continue to supply power to the device. An included novel circuit in the device then automatically reduces the input power from the batteries to the load (with the use of Pulse Time Modulation controlled by a feedback circuit) to an amount sufficient only to replace power losses to maintain just the residual power thus maintaining the desired power output with a minimum of power input thereby prolonging the battery life.
Thus, the present invention relates to an improved portable energy storage device (such as a hair curler and/or a hot air brush, flat iron, rotating mass, and the like) that utilizes an external power source to cause the device reach its desired operating condition (e.g. temperature, speed, momentum, and the like) and then utilizes internal batteries with a regulated pulse time modulated output as a power source providing sufficient power only to replace power losses, PL, and to make the device portable.
As used herein, the term “external power source” means any one of AC, DC, RF energy, magnetically coupled energy, and the like. Hereafter, for simplicity, the term will be identified as simply AC or DC. The energy consuming device, when a temperature controlled device, may have either a single heating element for accepting an external DC power source output for preheating as well as the internal power source (at least one battery) output to maintain the desired operating level or an AC heating element for connection to an external AC power source to obtain the desired operating level and a separate DC heating element for connection to the internal power source to maintain the desired operating level.
With the present invention, an electrical energy storage device is brought to its desired operation condition by applying full input power, PIN, from an external power source as explained earlier until the desired operating condition is reached. Thus, the device is caused to store the desired potential energy without using the internal batteries (i.e. extending the battery life). At that point, the input power, PIN, is automatically reduced with the novel Pulse Time Modulation circuit disclosed in commonly assigned copending patent application Ser. No. 11/094,729, incorporated herein by reference in its entirety, to the amount of power losses, PL, occurring in the device and thus enables the residual power or energy, PR, that is stored in the device to substantially equal the desired output power, PO.
This is accomplished by providing a feedback circuit representing the desired operating condition of the energy storage device (i.e. temperature, rotational speed, light brightness, and the like) and generating a signal representative of the instantaneous value of the desired operating condition. That generated feedback signal is coupled as one input to a comparator. The other input is a variable time based electrical reference signal such as, for example only, a sawtooth reference waveform. When the feedback signal is less in amplitude than any portion of the sawtooth reference waveform, the output of the comparator is a pulse time modulated signal (PTM) that is coupled to, and actuates an electronic switch such as a power FET. The electrical load receives power from the power input source only when the electronic switch is actuated. The pulse time modulated signal is coupled to the gate of the electronic switch to automatically switch it ON and OFF at a rate sufficient to supply just enough power to the load to replace power losses (e.g. cooling in a heat storage device) and thus maintains the desired operating condition as determined by the feedback signal.
Also, for the improved circuit disclosed herein, where the input feedback signal is generated by a temperature sensor that provides a small input signal that must be amplified such as by a transistor, a fixed-bias may be provided to the base of the transistor rather than using self-biasing to form sharp, clean, pulses that are free from parasitic oscillation, 60 cycle hum, and the like.
The novel circuit, when controlling a portable light source, may use a feedback signal proportional to the heat of the light bulb filament or the light brightness as determined by any well-known light sensor, such as a cadmium-sulfide cell or a photo-detector, and thus provide power sufficient only to compensate for load losses such as filament cooling, and the like.
When controlling a portable rotating device that has momentum (stored energy or kinetic energy, the rotational speed of the device, as detected by an rpm indicator, for example only, can be used to generate a signal representative of the rotational speed and that signal can be used as the feed back signal, as described above, to drive the rotating device at a desired speed by supplying pulse time modulated signals to an electronic switch to apply power to the load sufficient only to compensate for load losses such as friction, system losses, and the like.
Thus, it is an object of the present invention to extend the life of batteries in a portable energy storage device by using an external power source to provide the power necessary to obtain a desired output power from an electrical load (such as to preheat an electrical load to a desired temperature), disconnecting the external power source and automatically connecting the batteries to the load and then using a Pulse Time Modulation circuit to regulate the battery power output to replace only the system and load losses thereby enabling any Residual Power associated with the load to equal the desired output power and therefore conserve battery input power and extend the life of the batteries.
It is another object of the present invention generate a feedback signal representing the desired operating condition of the load, compare the feedback signal with a variable time based electrical reference signal and generate the Pulse Time Modulated signals based on the comparison.
It has been found, in actual tests, (depending upon the type of energy storage device tested) that applying as little as 10% of the continuous maximum battery voltage to the load may be sufficient to maintain the desired operating condition such as temperature. This novel control circuit can be advantageously used with existing alternating current devices to minimize power use.
To accomplish this novel battery saving operation, a heat sensor, such as a tempistor or thermistor, and preferably an LM 34 thermistor made by National Semiconductor, provides the proper control.
In addition, it is an object of the present invention to provide a portable energy storage device comprising an external power source to bring the device load to a desired operating condition, internal batteries to power the device only in its portable state, and an electrical circuit coupled between the internal power source and the load for using pulse time modulated signals for regulating the power applied to the load in an amount sufficient only to maintain the stored energy of the device at the desired operating condition so as to conserve and extend internal battery life.
Thus, the present invention relates to apparatus for extending the life of batteries in a portable energy storage device comprising an external power source for causing the device load to reach a designated operating condition, PO; an internal power source in the device for supplying input power, PIN, to the load only when the external power source is disconnected from the device and making the device portable; and a pulse time modulated circuit coupled between the internal power source and the load for using pulse time modulated signals to cause input power, PIN, to be supplied to the load in an amount substantially equal to the device power losses, PL, sufficient only to maintain the designated operating condition, PO.
The present invention also relates to a method of extending battery life in a portable energy storage device and obtaining a desired output power, PO, from an electrical load, where PO=PIN−PL+PR, comprising the steps of: supplying a continuous external power input, PIN, to the load to achieve the desired output power, PO, and create a residual, or stored power, PR; disconnecting the device from the external power source and automatically causing internal batteries to drive the load; and automatically reducing the input power, PIN, to an amount sufficient only to replace system and load losses, PL, using Pulse Time Modulation to thereby maintain the desired power output, PO, equal to the residual power, PR, with reduced input power, PIN.
The present invention also relates to apparatus for extending battery life in a portable energy storage device and automatically obtaining a desired output power, PO, from an electrical load of a system with reduced input power, PIN, where PO=PIN−PL+PR where PL=Power losses expended in the load as well as any system losses, and PR=residual Power or energy stored in the load at the desired output power, comprising an external power source for supplying continuous input power, PIN, to the load to achieve the desired output power, PO, (e.g. preheat) with an accompanying residual power, PR, internal batteries that are automatically coupled to drive the load only when the external power source is disconnected; and a pulse time modulation circuit is coupled between the internal batteries and the load for automatically supplying Pulse Time Modulated power to the load to reduce the input power, PIN, applied to the load to an amount sufficient only to replace the power losses, PL, thereby just maintaining the residual power, PR, equal to the desired output power, PO, to conserve electrical power and prolong the life of the internal batteries.
The present invention also relates to a method of extending the life of batteries in a portable energy consuming device comprising the steps of: coupling an external power source to the device to cause the device load to reach a designated operating condition, PO, without using the internal batteries (thereby extending the battery life); supplying power, PIN, to the load with the batteries only when the external power source is disconnected from the device to make the device portable; and coupling a circuit between the internal batteries and the load that uses pulse time modulated pulses to automatically cause the input power, PIN, to be supplied to the load in an amount substantially equal to the device power losses, PL, sufficient only to maintain the designated operating condition, PO, thereby extending the life of the internal batteries.
These and other more detailed objects of the present invention will be disclosed more fully when taken in conjunction with the following DETAILED DESCRIPTION OF THE DRAWINGS in which like numerals represent like elements and in which:
When the device 10 is preheated to the proper temperature (which may also be regulated with devices such as thermocouples and the like), the switch arms 21 are moved to contacts 25 (either manually or by the removal of the portable energy storage device from a base) and power from the battery cells 29, 31 flows through conductor 27 to switch arms 28 and conductor 15 to the control circuit 70. The energy storage device is now portable and operates from its internal battery cells 20, 31. This energy storage device has a DC heating element (energy storage device) 22 that is preheated by DC power from the AC/DC rectifier circuit 30 and then operated as a portable device using DC power from its own internal batteries.
An alternate embodiment of the energy storage device is disclosed in
Of course, the internal power source 20 may consist of the internal batteries and a pulsing circuit as will be shown hereafter to pulse the power of the internal batteries to the load. In such case, the life of the internal batteries is extended as will be disclosed hereafter.
Consider, as an example only, a hair curling iron. The iron has a metal mass serving as the heated surface and it must be raised to a sufficiently high temperature to enable it to be used. This is accomplished in the prior art by the use of alternating current (AC) and it takes several minutes to bring the metal mass to a temperature sufficient for use in curling hair. Then when it is used, the AC power cord must remain attached to keep the iron hot.
It is highly desirable to make the curling iron portable and eliminate the physical interference of the AC cord. However, if the curling iron is made portable, no cord is attached and no AC is used. Thus, the internal power source, without AC, must be placed under a severe power drain to bring the device to the desired operating level (in this example, temperature).
Thus, it can be seen with the block diagram of
In the generalized embodiment shown in
Also, as shown in
Of course, the device 12 illustrated generally in
At the same time, if desired, the AC input can be connected to an AC/DC converter 30, either internal or external (shown here as internal) that can be used to charge the internal batteries 20 in a conventional manner as explained earlier.
When the AC heating element 18 causes the device 12, here a temperature device, to reach the desired operating level (store the desired temperature in this case), the energy storage device is withdrawn from the mating receptacle connector 26, on a base unit if desired, to make the device portable. When that happens, switch 28 returns to its normally closed position thereby connecting internal power source 20 to its own DC load 22 on line 36. As will be shown hereafter in relation to
The circuit shown schematically in
An electronic switch 40, such as a power FET, is opened and closed by the control circuit 38 with the use of Pulse Time Modulated signals to modulate the power signal to load 22 from the internal power source 20 to provide only sufficient power to maintain the desired temperature. A light emitting diode (LED) 42 may be utilized, if desired, to let the user know that the control circuit 38 is functioning.
The novel invention works well with any load requiring heavy current to bring it to a desired operating level as explained earlier.
The novel invention works well with any load requiring heavy current to bring it to a desired operating level as explained earlier.
It will be noted in
The flat iron 46 could, if desired, have only one heating element and that is a DC heating element that would be used first during the preheating on the base unit 44 and then, when the flat iron 46 is disconnected from the base unit 44 to make the flat iron portable, the single DC heating element would be connected to the internal power source 20 to just maintain the desired temperature.
As shown in
The AC input from the external power source is connected directly to connector 62 on the base unit 44 while the DC power for simultaneously charging the internal power source comes from an AC/DC converter 58 whose DC output is coupled to connector 60. The power cord 16 terminates at the base unit 44 with a connector 56. Advantageously, connector 56 is identical to the connector 62 on base unit 44. If, for any reason, the portable operation of the device 64 is prohibited, the AC connector 56 can be plugged directly into the device 64 where power is normally supplied by connector 62. In such case, the hair curling iron 64 may advantageously continue to be used as a conventional cord attached, non-portable hair curling device.
In any use of batteries with a heating device, the batteries must not be subject to heating from the heating elements. In a hair curling iron, the batteries may be placed in a heat insulated handle as is well-known in the art and which is heat insulated from the heating element.
Briefly, however, unit 78 is a detector that senses the desired operating level (e.g. a temperature sensor 80 as shown in
However, as explained earlier, to save the internal batteries, the device has, in this instance, an AC heating element 18 that is heated to bring the device to the desired operating temperature. As can be seen in
As explained earlier, the male connector, represented by phantom line 26, physically opens switch 28 thus preventing the FET from receiving any signal from the control circuit of the device when the device is on the base unit. Thus no power is being supplied to the DC load 22 during the time that the external AC power source is heating the device to the desired operating temperature with the use of AC heating element 18. When the AC heating element or load 18 causes the device to reach the desired temperature (which can be indicated in a well known manner by illumination of an LED), the device is removed from its base unit and the male connector 26 is removed from the portable energy storage device closing switch 28 and allowing the signal from the comparator 92 of the control circuit to be connected to the power FET 102 which begins to apply power to the DC load 22. Because DC load 22 is in physical proximity to the metal mass that has been heated by the external power source 44, the DC load 22 is already heated to the approximate desired operating temperature and the power FET 102 now is Pulse Time Modulated by the control circuit to provide just enough energy to DC load 22 to maintain the desired operating temperature of the device.
An LED 103, if desired, may be coupled across FET 102 and pulses with the pulsing of the FET to indicate to the user that the control circuit is functioning.
Thus, there has been disclosed a novel improved portable energy storage device that uses an external power source to cause the device to reach a desired operating level and then when the device is removed from its base, the external power source is disconnected from the device and the internal power supply is then automatically connected to a DC load to maintain the desired operating level of the device. A control circuit is coupled between the internal power source and the DC load to Pulse Time Modulate the signal applied thereto to replace only load losses and to just maintain the desired operating level. As explained earlier, the desired operating level is intended to mean a desired operating temperature, a desired operating rpm, or any other type of load operating condition that has stored kinetic or potential energy that will maintain the desired operating condition if sufficient energy is provided to just replace the device losses.
While particular embodiments of the invention have been shown and described in detail, it will be obvious to those skilled in the art that changes and modifications of the present invention, in its various embodiments, may be made without departing from the spirit and scope of the invention. Other elements, steps, methods, and techniques that are insubstantially different from those described herein are also within the scope of the invention. Thus, the scope of the invention should not be limited by the particular embodiments described herein but should be defined by the appended claims and equivalents thereof.
