Methods and system for induction heating

Abstract

To provide a method and system for induction heating.SOLUTION: A system may provide a first induction coil 125 wrapped around a metal cylinder and a second induction coil 130 wrapped around the metal cylinder. The first induction coil may carry a current in a first direction and the second induction coil may carry a current in an opposite, second direction. The currents may be generated in an alternating sequence.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] Many electronic devices use lithium-ion batteries to provide the primary power source for the electronic device. Uses batteries such as batteries. Electronic cigarettes (vaping devices, e-cigarettes, vapes) Also known as pens, nicotine vaporizers, hybrid e-cigarettes, and real tobacco e-smokes In some applications, such as in the vaping and vaping industry, batteries heat liquid or dried tobacco to produce vapor. Some conventional systems use a heater to power a heating element that is used to The final target (often a metal cylinder) is then indirectly heated. The heating method may take an undesirable amount of time to heat up to the desired temperature and may require more time to heat up at a faster rate. Increasing the temperature requires increased power consumption. It may be desirable to use a laser to directly heat the final target. Summary of the Invention

[0002] Various embodiments of the present technique provide methods and systems for induction heating. The first induction coil is wound around a metal cylinder, and the second induction coil is wound around the metal cylinder. and a second induction coil attached to the first induction coil. The first induction coil may be configured to pass a current in a first direction. and a second induction coil may pass a current in a second opposite direction. It can be generated in [Brief description of the drawings]

[0003] A more complete understanding of the present technology may be obtained in conjunction with the following illustrative figures, in which: In the following figures, like reference numbers refer to the entire It refers to similar elements and steps.

[0004] [Figure 1] 1 depicts a representative illustration of an induction heating system, in accordance with an exemplary embodiment of the present technique;

[0005] [Diagram 2] 1 is a flow chart for operating a system in accordance with an exemplary embodiment of the present technology.

[0006] [Diagram 3] 1 illustrates operational states of a first switch and a second switch and corresponding pulse signals in accordance with an exemplary embodiment of the present technology;

[0007] [Figure 4] 1 is a graph illustrating the relationship between a battery's voltage and the battery's relative state of charge, in accordance with an exemplary embodiment of the present technology;

[0008] [Diagram 5] 1 is a graph illustrating the relationship between the pulse period of an operating state and the relative state of charge of a battery, in accordance with an exemplary embodiment of the present technique.

[0009] [Figure 6] FIG. 2 is a block diagram of a control circuit, in accordance with an exemplary embodiment of the present technique. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present technology may be described in terms of functional block components and various process steps. A functional block is any component configured to perform a particular function or achieve a particular result. For example, the technology may be implemented with a variety of components that may perform a variety of functions. heating elements, signal and pulse generators, voltage sensors, current sensors, coulomb counters, logic Semiconductor devices such as gates, memory devices, transistors and capacitors are used. In addition, the technology can be implemented in conjunction with any number of systems. The described system is merely an exemplary application for this technique. Measuring voltage, measuring current, calculating battery capacity, various mathematical calculations Employing any number of conventional techniques for performing calculations, storing data, etc. This can be done.

[0011] Methods and apparatus for dielectric heating according to various aspects of the present technology are useful in home appliances, portable devices, Operates with any suitable electronic system and / or device, such as a battery-powered heating device, Referring to FIG. 1, the exemplary system 100 may be powered by a rechargeable battery 115. A control circuit for controlling the amount of power supplied to the heating element 103 and the heating element 103 and a control circuit 105. In one application, the system 100 may include a liquid (i.e., an electronic cigarette used to heat a cartridge that contains a gas cartridge; and hybrid electronic cigarettes used to heat dried tobacco leaves or traditional cigarettes. In various embodiments, the system may be incorporated into various electronic cigarettes, such as a cigarette dispenser. 100 detects when a user applies draw (i.e., a puff) to the e-cigarette. The control circuit 105 and / or the heating element 10 may further include a sensor 192 for detecting the temperature of the heating element 10. Start 3.

[0012] The battery 115 may be used to power the heating element 103 and / or the control circuitry 105 of the system 100. The battery 115 may be a rechargeable lithium ion battery or the like. Alternatively, the battery 115 may comprise a nickel metal hydride battery, a nickel Lithium cadmium batteries, or lithium cobalt, lithium iron phosphate, lithium titanate, or The battery may include a lithium-based battery such as a lithium polymer battery.

[0013] The heating element 103 is surrounded by a first induction coil 125 and a second induction coil 130. The heater may be configured as an induction heater with an enclosed hollow vessel 120. The vessel 120 may be filled with magnetic material. The material may be made of, for example, a carbon steel alloy, or any other steel alloy. The container 120 has a cylindrical shape having a first end 180 and an opposite second end 185. The container 120 may be a dry tobacco, a conventional cigarette, or a vapor cartridge, etc. The device may be further adapted to hold or contain a substance.

[0014] The first induction coil 125 may include a first end 160 and a second end 165. An induction coil 125 is wrapped around the outer wall of the vessel 120 and runs along the length of the vessel 120. Similarly, the second induction coil 130 may have a first end 170 and The second induction coil 130 may have a second end 175 and may be wound around the outer wall of the container 120. The tubular members 122 may be attached to each other to form a spiral shape along the length of the vessel 120. In various embodiments, each The induction coils 125, 130 operate independently of each other.

[0015] According to an exemplary embodiment, the first end 160 of the first induction coil 125 is connected to the battery 11. 5, and the second end 165 can be connected through the first switch 145. In addition, the second inductor coil 130 may be selectively connected to a reference voltage such as ground potential. The first end 175 may be connected to the positive terminal (+) of the battery 115, and the second end 170 may be connected to the positive terminal (+) of the battery 115. The input terminal 140 may be selectively connected to a reference voltage via a switch 140 .

[0016] Alternatively, the first end 160 of the first induction coil 125 may be connected to the negative terminal (-) of the battery 115. , and the second end 165 can be selectively connected to a positive voltage potential via the first switch 145. In addition, the second end 175 of the second induction coil 130 may be connected to the The first end 170 may be connected to the negative terminal (-) and the first end 170 may be connected to a positive voltage via the second switch 140. The electrodes can be selectively connected to an electrical potential.

[0017] In addition, the system 100 may be configured to provide a stable operation of the heating element 103 and / or the first induction coil. 1 for providing a stable generation of current through the first induction coil 125 and the second induction coil 130. For example, the first capacitor 155 may include a first induction coil 1 25 between a first end 160 and a second end 165 of the second connector 160. The capacitor 150 is disposed between the first end 170 and the second end 175 of the second induction coil 130. can be connected to

[0018] According to an exemplary embodiment, the control circuit 105 controls the first switch 145 and the second switch By applying a signal (or pulse) to switch 140, heating element 103 is selectively activated. For example, the control circuit 105 selectively operates the first switch 145 to A first current I1 may be generated or otherwise controlled through one induction coil 125. Similarly, the control circuit 105 selectively operates the second switch 140 to switch the second inductor A second current I2 may be generated or otherwise controlled through the coil 130. The switches 140, 145 are responsive to signals and provide a desired voltage and / or current between two or more devices. It may include any device suitable for providing selective connection to an electrical potential.

[0019] Each of the first switch 145 and the second switch 140 uses an electric field to Field effect transistors (FETs) that control electrical behavior There are many different implementations of field effect transistors. Effect transistors generally exhibit very high input impedance at low frequencies. Therefore, this may be a desirable implementation.

[0020] 1 and 6, the control circuit 105 receives various input signals, such as an input signal from a sensor 192. It controls and / or manages the functioning of the battery 115 and heating element 120 according to various input signals. Control circuitry 105 includes a variety of controls that work together to provide the desired output and / or control signals. The control circuit 105 may include an integrated circuit that includes the circuits and / or systems. The battery 115 is connected to the battery and configured to measure various battery characteristics such as voltage, current, and temperature. It is possible.

[0021] According to an exemplary embodiment, the control circuit 105 includes a voltage sensor 198, an on / off control circuit circuit 182, logic circuit 191, memory 194, pulse generator 190, pulse controller 1 97, a timer 193, a first driver 196, and a second driver 195, These operate together to perform various functions of the system 100, such as measuring the voltage of the battery 115. determining the desired pulse period; calculating the relative state of charge of the battery 115; 103, controlling or otherwise regulating the temperature of the heating element 102 (e.g., controlling the power to the heating element 103). The control circuit 105 may be formed as an integrated circuit on a single chip, or may be implemented as a multi-chip integrated circuit. The data can be accumulated across a group.

[0022] The on / off control circuit 182 determines whether a user has taken a "puff" from the electronic cigarette. In such a case, the on / off control circuit 1 may respond to a signal from a sensor 192 indicating whether the 82 may generate one or more activation signals to initiate various actions, e.g., on / off The control circuit 182 sends a wake-up signal to the logic circuit 191 to activate the logic circuit 191 and / or the timer. The operation of the timer 193 can be initiated by activating the timer 193. The circuit 182 acts as an interface between the sensor 192 and the control circuit 105. The control circuit 105 may include any circuitry and / or devices suitable for activating other components in the control circuit 105. It is possible.

[0023] The voltage sensor 198 detects and / or measures the voltage of the battery 115. The sensor 198 may be connected to the positive terminal of the battery 115 and may be a conventional sensor that measures voltage based on a voltage divider. A voltage sensor 198 may also be connected to the logic circuit 191 to detect the voltage of the battery 1 15 measurement voltages to logic circuit 191. Alternatively, or in addition, , the voltage sensor 198 may transmit the measured voltage to the memory 194 .

[0024] Logic circuitry 191 performs various calculations to determine the desired timing for operating heating element 103. For example, the logic circuit 191 may be configured to determine the relative timing of the battery 115. Determines the relative state of charge (RSOC) and optimizes performance based on RSOC. The pulse period may be selected.

[0025] According to an exemplary embodiment, the logic circuit 191 is coupled to the on / off control circuit 182. , may be responsive to a wake-up signal. For example, logic circuit 191 may It may then be configured to perform a series of steps.

[0026] In addition, the logic circuitry 191 may be in communication with a memory 194. For example, the logic circuitry Path 191 delivers data to and / or retrieves data from memory 194. In an exemplary embodiment, logic circuit 191 may It may be utilized to perform calculations and / or make decisions regarding the operation of the heating element 103 .

[0027] The memory 194 may be accessible to the logic circuit 191 and may store various data points and / or In an exemplary embodiment, the memory 194 may be configured to store a collection of data. Record the battery voltage values ​​and the corresponding RSOC values ​​for each voltage value (such as the data shown in Figure 4). For example, the memory 194 may store a lookup table suitable for storing relational data. Record the battery voltage and RSOC values ​​in a backup table or any other storage solution. In addition, the memory 194 may store RSOC values ​​and corresponding performance data for each RSOC value. For example, the memory 194 may store a relay period (such as the data shown in FIG. 5). A lookup table or other storage solution suitable for storing the global data. The RSOC value and pulse period can be stored in the

[0028] In an exemplary embodiment, the memory 194 indicates the relationship between the RSOC value and the pulse period. A plurality of data sets may be stored, each data set being associated with a heating element 103 (and corresponding target For example, if the heating element 103 is in an initial state and the temperature and A first set of data may be used when the power is at an initial value. In this case, the heating element 103 may be used after it is activated, and the temperature of the heating element 103 may be adjusted to the initial temperature. Higher than average.

[0029] The pulse generator 190 may be responsive to a logic circuit 191 and may generate a first pulse signal and a second pulse signal. The first and second pulse signals may be configured to generate an output that may be represented as a pulse signal. For example, the pulse generator 190 generates a first pulse signal and a second pulse signal. Alternatively, the pulse generator 190 may generate an AC pulse waveform that may be divided into a pulse signal. , two separate pulse signals can be generated. The pulse generator 190 generates an AC pulse signal. The pulse period and / or frequency of the pulse signal may be determined by any suitable circuit and / or system. Or the duty cycle is controllable.

[0030] In one embodiment, the pulse generator 190 operates according to a signal (voltage) from a logic circuit 191. H-blocks comprise a collection of transistors that can be turned "on" and "off" in an AC arrangement. The AC operating arrangement may include a first output terminal and a second output terminal of the pulse generator 190. This results in an inversion state at the output terminals. For example, the polarity at the output terminals is inverted, resulting in a positive So when one terminal is positive, the other terminal is negative. In this case, the first output terminal can generate a first pulse signal, and the second output terminal can generate , a second pulse signal may be generated.

[0031] In various embodiments, the pulse generator 190 may also be responsive to a timer 193. The counter 193 may be configured to generate a count value and controlled by the on / off control circuit 182. The timer 193 may send a count value to the pulse generator 190. The pulse generator 190 generates an output waveform (parallel and first and second pulse signals).

[0032] The first driver 196 is connected to the first output terminal of the pulse generator 190 and drives the first The second driver may be configured to apply a pulse signal to the first switch 145. The second switch 140 is connected to the pulse generator 190 and supplies a second pulse signal to the second switch 140. Therefore, the drivers 195, 196 can be configured to apply the In other words, when one switch is on, the other switches The drivers 195, 195 transmit signals to loads such as the switches 140, 145. It may comprise any suitable circuitry and / or devices for relaying and / or driving.

[0033] The pulse controller 197 may be connected to the pulse generator 190 and may control the first and second pulses. The pulse controller 197 may be configured to provide a delay to prevent overlapping of the pulse signals. The device may comprise any circuit and / or device suitable for performing the steps of:

[0034] In operation, and with reference to FIGS. 1-6, the control circuit 105 controls the first switch 1 45 and the second switch 140 are operated, thereby turning on the first induction coil 125 and The control circuit 130 may generate alternating and opposing currents through the first and second induction coils 130. 105 switches the first switch 145 and the second switch 146 according to a pulse period based on the battery voltage and RSOC. and the second switch 140 may be operated.

[0035] In an exemplary operation, the on / off control circuit 182 controls the on / off state based on information from the sensor 192. For example, the on / off control circuit 182 may activate the operation of the logic circuit 191. When the logic circuit 191 is activated, it reads the target power from the memory 194 (200). The target power may be obtained based on the desired operating specifications of the system 100 and / or the measured temperature, and / or may be preset values ​​based on the operating specifications of the device incorporating system 100. The logic circuit 191 may then measure the voltage of the battery 115 (205). The logic circuit 191 may measure the voltage using a voltage sensor 198. 1 may determine the RSOC of the battery 115 (210). For example, the logic circuit 191 may The RSOC value corresponding to the measured voltage may be obtained from the resistor 194 (from step 205). For example, referring to Figure 4, when the measured voltage is 3.8V, the corresponding RSOC is 70%. be.

[0036] Logic circuit 191 then determines based on the RSOC value (as determined from step 210). For example, referring to FIG. 5, the R When the SOC is 70%, the corresponding pulse period is, for example, about 73 seconds, and when the SOC is 50%, As RSOC increases, the pulse period also increases and vice versa. And similarly, RSOC and the pulse period are thus directly proportional.

[0037] The logic circuit 191 then generates a corresponding signal (e.g., a voltage or a current) and The pulse generator 190 may then transmit the first and second pulses. The first and second pulse signals may be non-overlapping and each may generate an output waveform including a pulse signal. A first pulse signal having a desired pulse period (as determined from step 215) is generated. A second pulse signal is applied to the first switch 145 and a second pulse signal is applied to the second switch 140 (2 20). A longer pulse period results in a lower frequency signal, while a shorter pulse The period results in a higher frequency signal. In an exemplary application, the higher frequency is This results in a higher temperature on the container 120 where the tobacco or dried tobacco is inserted, and a lower frequency The numbers result in lower temperatures.

[0038] When each switch 140, 145 is switched on and off, each switch Connect each induction coil to ground potential to generate a current flow through each induction coil. Since the switches 140, 145 are operated in sequence, the current flow is also generated in sequence. In addition, since the induction coils 125, 130 are arranged in a reversing manner, the first current I1 flows in the The first current I flows in a first direction and the second current I2 flows in an opposite second direction. The pair of currents generates opposing magnetic fluxes. AC operation of the induction coils 125, 130 provides a stable Magnetic flux may provide efficient energy usage and rapid heating of the vessel 120 .

[0039] In various embodiments, the logic circuit 191 may be configured to detect changes in the temperature of the heating element 103 as the temperature of the heating element 103 changes during operation. The logic circuit 191 then calculates the new target power (230). Based on the change in the target power and / or temperature, a new pulse period may be determined. The circuit 191 may obtain a new pulse period from the memory 194.

[0040] Periodically, while the system 100 is in operation, the control circuit 105 determines the new battery voltage (205 ) is periodically measured to determine a new RSOC (210) and a new pulse period (215) is determined, and the pulse signals are applied to the switches 140, 145 (220) as described above. It can maintain a stable temperature of the thermal element 103. For example, a battery with a higher voltage can be used with a cigarette lighter. By providing a higher temperature on the container 120 where the cigarette or paper is inserted, a lower voltage is applied. The battery that uses the battery provides a lower temperature, so the temperature of the heating element 103 can be kept stable. To keep the battery charge constant, the system 100 operates according to the battery voltage (which has an inverse relationship to RSOC). For example, when the battery voltage is high, the system 100 , a pulse signal having a lower frequency may be generated when the battery voltage is low, and the system 100 may generate a pulse signal having a higher frequency.

[0041] In the preceding description, the technology has been described with reference to specific exemplary embodiments. The specific implementations shown and described are illustrative of the technology and its best mode and are not to be construed as limiting the scope of the invention in any way. However, it is not intended to otherwise limit the scope of the present technology. Indeed, for the sake of brevity, For purposes of this description, conventional manufacturing, connection, preparation, and other functional aspects of the methods and systems have been described in detail. Additionally, the connecting lines shown in the various figures may represent exemplary functions between the various elements. In practical systems, many Alternative or additional functional relationships or physical connections may be present.

[0042] The present technology has been described with reference to certain exemplary embodiments. Various modifications and changes may be made without departing from the scope of the invention. , should be regarded as illustrative and not limiting, and all such modifications are within the scope of the present technology. It is intended that the scope of the technology be limited solely to the specific implementations described above. By way of example only, the following general embodiments and their legal equivalents are described: For example, the steps described in any method or process embodiment may be Unless expressly stated otherwise, the steps may be performed in any order and may be performed in any order as presented in a particular embodiment. Furthermore, the components and steps described in any apparatus embodiment are not limited to the explicit order shown. The elements and / or components may be assembled in various permutations to produce substantially the same results as the present technology. may be configured to operate in a different manner, and thus may vary depending on the particular embodiment. It is not limited to the particular configurations described.

[0043] Benefits, other advantages, and solutions to problems have been described above with respect to certain embodiments. However, any benefits, advantages, solutions to problems, or any particular benefits, advantages, or Any element that can give rise to or make more prominent a problem or solution is considered an important, necessary The appended claims should not be construed as an essential or required feature or component.

[0044] The terms "comprises", "comprising" or any variation thereof is intended to refer to a non-exclusive inclusion and therefore to a process that includes a list of elements The invention relates to a method, article, composition, or apparatus that includes but is not limited to the elements described. The present invention is not expressly recited or inherent in the process, method, article, composition or apparatus. In addition to those not specifically described, other elements may be included that may be used in the practice of the present technology. Any other combinations of the above-mentioned structures, arrangements, uses, proportions, elements, materials, or components and and / or modifications may be modified or otherwise altered without departing from their general principles. The method may be specifically adapted to a particular environment, manufacturing specifications, design parameters, or other operating requirements.

[0045] The present technology has been described above with reference to exemplary embodiments. However, the scope of the technology Changes and modifications may be made to the exemplary embodiments without departing from the scope of the invention. These and other changes or modifications are within the scope of the present technology as expressed in the following claims. This is what is intended.

[0046] According to a first aspect, a device for induction heating powered by a battery is provided, a first induction coil having a first end connected to a terminal of the battery through a node; a second induction coil having a second end connected to the battery terminal and a node a second induction coil having a second end connected to the first terminal; a first switch device configured to selectively connect the a second switch configured to selectively connect the first end of the induction coil to a voltage potential; and a touch device.

[0047] In one embodiment, the first induction coil and the second induction coil are arranged around a single magnetic cylinder. The magnetic cylinder has a first end and a second end.

[0048] In one embodiment, the first end of the first induction coil is directly connected to the first end of the magnetic cylinder. and a second end of the first induction coil is directly adjacent to the second end of the magnetic cylinder. The first end of the second induction coil is directly adjacent to the second end of the magnetic cylinder, and the second The second end of the induction coil is directly adjacent the first end of the magnetic cylinder.

[0049] In one embodiment, the device is connected between a first end and a second end of a first induction coil. a first capacitor connected between the first end and the second end of the second induction coil; and a second capacitor.

[0050] In one embodiment, the battery terminal is a negative battery terminal and the voltage potential is a positive voltage potential.

[0051] In one embodiment, the battery terminal is a positive battery terminal and the voltage potential is ground potential.

[0052] In one embodiment, the first induction coil is adapted to generate a first current flowing in a first direction. and a second induction coil configured to generate a second current flowing in an opposite second direction. It is composed of:

[0053] According to a second aspect, a method for operating a battery powered induction heater is provided. Thus, the induction heater has a first induction coil and a second induction coil, and the method includes: Determining a target power to be applied to a heater, determining battery characteristics, and generating a pulse signal; and inducing a first induction coil according to the target power and the pulse signal. generating a first current having a first direction through the target power and pulse signal; Thus, a second electric current having a second direction opposite to the first direction is generated through the second induction coil. and generating a flow.

[0054] In one embodiment, determining the battery characteristics includes measuring the voltage of the battery during a no-load condition. and determining the relative state of charge of the battery based on the measured voltage.

[0055] In one embodiment, generating a pulse signal in accordance with the battery characteristic comprises determining a relative determining a pulse period based on a charging state; and and generating a signal.

[0056] In one embodiment, the length of the pulse period is directly proportional to the value of the relative state of charge.

[0057] In one embodiment, generating the first current comprises: Thus, generating a second current includes operating the first switch. and operating a second switch in accordance with a second portion of the generated pulse signal.

[0058] In one embodiment, a first portion of the generated pulse signal and a second portion of the generated pulse signal are The part is a non-overlapping pulse.

[0059] In one embodiment, generating the first current comprises selectively connecting the first induction coil to a ground potential. and generating a second current includes connecting the second induction coil to a ground potential. This includes selectively connecting.

[0060] According to a third embodiment, the system includes a sensor connected to the positive terminal of a battery at a node and a control circuit responsive to the sensor signal; and an induction heating device connected to the control circuit and the battery via a node. a first end of the magnetic cylinder wrapped around the magnetic cylinder and connected to a node; A first induction coil is wound around the magnetic cylinder and connected to the node. a second induction coil having a second end connected to the induction heating device; and a control circuit. a first switch device responsive to and connected to a second end of the first induction coil; a second switch device responsive to the control circuit and connected to a first end of the second induction coil. It is equipped with a

[0061] In one embodiment, the first and second switch devices are also connected to a ground potential.

[0062] In one embodiment, the first end of the first induction coil is directly connected to the first end of the magnetic cylinder. and a second end of the first induction coil is directly adjacent to the second end of the magnetic cylinder. The first end of the second induction coil is directly adjacent to the second end of the magnetic cylinder, and the second The second end of the induction coil is directly adjacent the first end of the magnetic cylinder.

[0063] In one embodiment, the system includes a first inductive coil connected between a first end and a second end. a first capacitor connected between the first end and the second end of the second induction coil; and a second capacitor connected to the first capacitor.

[0064] In one embodiment, the control circuit is configured to generate the first pulse signal and the second pulse signal. and the first and second pulse signals are non-overlapping pulse signals.

[0065] In one embodiment, the first switch device is responsive to the first pulse signal and The touch device responds to a second pulse signal.

Claims

1. 1. An apparatus for induction heating powered by a battery, comprising: a first induction coil having a first end connected to a terminal of the battery at a node; a second inductive capacitor having a second end connected to the terminal of the battery through the node; Ile and a second end of the first induction coil configured to selectively connect to a voltage potential; a first switch device; a first end of the second induction coil configured to selectively connect to the voltage potential; and a second switch device.

2. The first induction coil and the second induction coil are wound around a single magnetic cylinder. the magnetic cylinder having a first end and a second end; The first end of the first induction coil is directly connected to the first end of the magnetic cylinder. a second end of the first induction coil directly adjacent to the second end of the magnetic cylinder; It is adjacent to The first end of the second induction coil is directly connected to the second end of the magnetic cylinder. the second end of the second induction coil is adjacent to the first end of the magnetic cylinder. The apparatus of claim 1 , wherein the first and second electrodes are disposed adjacent to each other.

3. the first induction coil is configured to generate a first current flowing in a first direction; The second induction coil is configured to generate a second current flowing in an opposite second direction. The apparatus of claim 1 .

4. 1. A method for operating a battery-powered induction heater, comprising: has a first induction coil and a second induction coil, and the method comprises: determining a target power to be applied to the induction heater; Determining a battery characteristic; generating a pulse signal in accordance with the battery characteristics; According to the target power and the pulse signal, a first direction is generated through the first induction coil. generating a first current having a first direction; According to the target power and the pulse signal, the first induction coil is and generating a second current having a second direction opposite to the direction of the first current.

5. generating the pulse signal in accordance with the battery characteristics; determining a pulse period based on the determined relative state of charge; and generating the pulse signal based on the determined pulse period; 5. The method of claim 4, wherein the length of the pulse period is directly proportional to the value of the relative state of charge. method.

6. Generating the first current includes selectively connecting the first induction coil to a ground potential. This includes: Generating the second current selectively connects the second induction coil to the ground potential.

5. The method of claim 4, further comprising:

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