Stable discharge circuit for electric flame

Abstract

The application discloses a stable discharging circuit of an electric flame cooker and the electric flame cooker, and belongs to the technical field of electric flame cookers. The stable discharging circuit of the electric flame cooker comprises a single boosting transformer and multiple groups of discharging circuits; the multiple groups of discharging circuits comprise a first discharging circuit, a second discharging circuit and an Nth discharging circuit which are connected in parallel with each other. The single discharging circuit of the application cannot pull down and clamp the voltage of other discharging circuits when first breakdown occurs, all discharging devices (positive and negative electrodes) can be reliably broken down in turn, and the phenomenon of no current and no discharging in some branches is eliminated; under the stable state, the electrode voltages of all branches are consistent, the currents are balanced, and the sizes of plasma flames are uniform.

Description

Technical Field

[0001] This invention specifically relates to the discharge circuit of an electric flame stove. Background Technology

[0002] Electric flame stoves employ multiple high-voltage discharge devices (connected in parallel with positive and negative electrodes in an air-tight discharge configuration). Each device generates an electric field by breaking down the gas flow under high voltage. The gas flow collides with electrons in the electric field, ionizing the gas molecules and exciting plasma. This plasma has a temperature of over 1000 degrees Celsius and is used to heat cookware. Currently, electric flame stoves on the market are also known as electric fire stoves, electric fire starter stoves, electric flame stoves, electric gas stoves, electric open flame stoves, plasma stoves, etc. All of these stoves utilize the working principle of high-voltage air breakdown to excite plasma for heating cookware.

[0003] In order to provide a continuous and stable high voltage, the transformer needs to step up the voltage and then rectify it through the high-voltage discharge branch to output high-voltage DC power to the positive terminal of the high-voltage discharge device.

[0004] In this field, the impedance of the load in an electric flame stove changes at high frequency, frequently switching between "airflow (high sampling resistance) - plasma (low sampling resistance) - airflow (high sampling resistance) - plasma (low sampling resistance)," causing high-frequency fluctuations in current. Existing electric flame stove technologies typically employ multiple, even hundreds, high-voltage discharge devices, using multiple sets of input terminals connected in parallel to the same transformer secondary winding in a voltage multiplier rectifier branch. Each branch supplies high-voltage DC power to its corresponding high-voltage discharge device. However, this circuit exhibits a phenomenon where some voltage multiplier rectifier branches (high-voltage discharge devices) have high current while others have no current. This is due to the combined effects of the breakdown voltage difference of the discharge load, the voltage clamping / voltage drop effect of the parallel circuit structure, and is further amplified by differences in capacitor parameters and design flaws.

[0005] like Figure 1 As shown, taking two sets of voltage multiplier rectifier branches as an example, the breakdown voltage of the discharge device (plasma discharge head) is affected by factors such as gap distance, gas medium, and temperature. The two sets cannot be completely identical, and the breakdown discharge times of the two discharge devices cannot be the same. For example... Figure 1 As shown, for example, the load breakdown voltage of the discharge branch A above is lower, reaching the breakdown threshold first, and instantaneously conducting to form a low-resistance arc path, allowing a large current to flow. After conduction, this group of loads will "clamp" the output voltage of the transformer secondary to its breakdown voltage value. On the other hand, the load of the discharge branch B below requires a higher breakdown voltage. At this time, the secondary voltage has been pulled down, and the common ground potential has been pulled up. The voltage difference between the positive and negative electrodes of the discharge branch B is further reduced, and it can never reach its breakdown threshold. Therefore, it is always in an open circuit state, and thus there is no current.

[0006] The aforementioned design flaws only allow some discharge devices to break down and discharge, while others fail to do so. Therefore, those skilled in the art have improved the circuitry of existing technologies. For example, patent number 2024207121082 discloses an electric flame stove that uses an independent transformer at the input end of each voltage multiplier branch. This avoids multiple voltage multiplier branches sharing the same secondary winding. While this solves the problem of existing technologies, for high-power electric flame stoves with hundreds of discharge devices operating, hundreds of corresponding small transformers or secondary windings are required. This not only increases costs and makes the stove bulky, but also results in significant energy loss due to the cumulative energy loss from hundreds of transformers simultaneously performing "electrical energy to magnetic energy and then back to electrical energy." Furthermore, severe electromagnetic interference between numerous transformers affects circuit stability.

[0007] Therefore, those skilled in the art continued to improve the technology. For example, patent number 2025115774709 discloses a high-voltage circuit for an electric flame stove, in which a coupling capacitor is set in each voltage multiplier branch. This coupling capacitor blocks the DC component, allowing only the AC component to power the voltage multiplier module. The DC clamping and voltage drop of one group's discharge will not affect the AC input of the other group, and both groups can obtain sufficient AC boost energy. This coupling capacitor isolates the DC output terminals of the two voltage multiplier modules from each other, preventing the large DC current of one group's discharge from directly entering the other group, avoiding the phenomenon of low-resistance loads absorbing all the current. Multiple groups can independently complete boost and discharge. Even if the capacitor and boost diode parameters of the two voltage multiplier modules deviate, the coupling capacitor can make their AC input more independent, preventing the boost capability of the other group from being directly dragged down by the parameter problem of one group, thus achieving stable discharge of multiple voltage multiplier branches. However, this patented technical solution still has problems. The breakdown voltage of each group of discharge devices still has significant differences. Although some discharge devices will not have a completely "no current" phenomenon, the problem of uneven current distribution between the circuits still exists.

[0008] Furthermore, current electric flame cooktops on the market are only compatible with 220V-240V voltages. For the 110V AC mains power used in the United States and Japan, a separate circuit system needs to be developed. Using molds for two sets of electric flame cooktop circuits not only increases production and R&D costs but also complicates production management.

[0009] Therefore, this invention develops a wide circuit that can adapt to both voltage inputs of electric flame stoves, specifically targeting the 220V-240V high voltage and 110V low voltage in different countries, and can accommodate the simultaneous discharge of hundreds of discharge devices in the electric flame stove to generate plasma. Summary of the Invention

[0010] To overcome the shortcomings mentioned above, the present invention aims to provide a technical solution that can solve the above problems.

[0011] A stable discharge circuit for an electric flame stove includes: a single step-up transformer and multiple sets of discharge circuits; the multiple sets of discharge circuits include a first discharge circuit, a second discharge circuit, and an Nth discharge circuit connected in parallel with each other.

[0012] The first discharge circuit includes a first voltage doubler rectifier switching circuit, a first normally closed relay, a first buck switch, a first buck diode, a first inductor, a first boost switch, a first boost diode, a first capacitor, a first positive electrode, a first negative electrode, and a first sampling resistor; one end of the secondary winding of the boost transformer is connected to one input terminal of the first voltage doubler rectifier switching circuit, and the other end of the secondary winding of the boost transformer is connected to the other input terminal of the first voltage doubler rectifier switching circuit;

[0013] The positive output terminal of the first voltage doubler rectifier switching circuit is connected to the input terminal of the first normally closed relay and the source of the first buck switch. The drain of the first buck switch is connected to one end of the first inductor and the cathode of the first buck diode. The other end of the first inductor is connected to the anode of the first boost diode and the source of the first boost switch. The cathode of the first boost diode, the output terminal of the first normally closed relay, one end of the first capacitor, one end of the first sampling resistor, and the first positive electrode are all electrically connected. The negative output terminal of the first voltage doubler rectifier switching circuit, the anode of the first buck diode, the drain of the first boost switch, the other end of the first capacitor, and the first negative electrode are all electrically connected and grounded.

[0014] Preferably, the second discharge circuit includes a second voltage doubler rectifier switching circuit, a second normally closed relay, a second buck switch, a second buck diode, a second inductor, a second boost switch, a second boost diode, a second capacitor, a second positive electrode, a second negative electrode, and a second sampling resistor; one end of the secondary winding of the boost transformer is connected to one input terminal of the second voltage doubler rectifier switching circuit, and the other end of the secondary winding of the boost transformer is connected to the other input terminal of the second voltage doubler rectifier switching circuit;

[0015] Preferably, the positive output terminal of the second voltage doubler rectifier switching circuit is connected to the input terminal of the second normally closed relay and the source of the second buck switch, respectively; the drain of the second buck switch is connected to one end of the second inductor and the cathode of the second buck diode, respectively; the other end of the second inductor is connected to the anode of the second boost diode and the source of the second boost switch, respectively; the cathode of the second boost diode, the output terminal of the second normally closed relay, one end of the second capacitor, one end of the second sampling resistor, and the second positive electrode are all electrically connected; the negative output terminal of the second voltage doubler rectifier switching circuit, the anode of the second buck diode, the drain of the second boost switch, the other end of the second capacitor, and the second negative electrode are all electrically connected and grounded;

[0016] Preferably, the first voltage doubler rectifier switching circuit consists of a first normally open relay, four rectifier diodes, and two voltage doubler capacitors. The channel of the first normally open relay can control the output voltage of the first voltage doubler rectifier switching circuit to be one or two times.

[0017] Preferably, the second voltage doubler rectifier switching circuit consists of a second normally open relay, four rectifier diodes, and two voltage doubler capacitors. The channel of the second normally open relay can control the output voltage of the second voltage doubler rectifier switching circuit to be one or two times.

[0018] Preferably, the stable discharge circuit of the electric flame stove further includes a control circuit.

[0019] Compared with the prior art, the advantages of the present invention are: the breakdown of a single discharge circuit in the present invention will not pull down or clamp the voltage of other discharge circuits, all discharge devices (positive and negative electrodes) can be reliably broken down in sequence, eliminating the phenomenon of no current or no discharge in some branches; under steady state, the voltage of each electrode is consistent and the current is balanced, and the size of the plasma flame is uniform.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 It is a schematic diagram of existing technology.

[0023] Figure 2 This is a schematic diagram of the structure of the present invention.

[0024] Figure 3 This is a schematic diagram of Example 2. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] Furthermore, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Please see Figure 2 In this embodiment of the invention, a stable discharge circuit for an electric flame stove includes: a single step-up transformer ST1 and multiple sets of discharge circuits; the multiple sets of discharge circuits include a first discharge circuit 100, a second discharge circuit 200, and an Nth discharge circuit connected in parallel with each other.

[0030] The first discharge circuit 100 includes a first voltage doubler rectifier switching circuit CD1, a first normally closed relay NCR1, a first buck switch BuckQ1, a first buck diode BuckD1, a first inductor L1, a first boost switch BoostQ1, a first boost diode BoostD1, a first capacitor C1, a first positive electrode PE1, a first negative electrode NE1, and a first sampling resistor R1; one end of the secondary winding of the boost transformer ST1 is connected to one input terminal of the first voltage doubler rectifier switching circuit CD1, and the other end of the secondary winding of the boost transformer ST1 is connected to the other input terminal of the first voltage doubler rectifier switching circuit CD1.

[0031] The positive output terminal of the first voltage doubler rectifier switching circuit CD1 is connected to the input terminal of the first normally closed relay NCR1 and the source of the first buck switch BuckQ1. The drain of the first buck switch BuckQ1 is connected to one end of the first inductor L1 and the cathode of the first buck diode BuckD1. The other end of the first inductor L1 is connected to the anode of the first boost diode BoostD1 and the source of the first boost switch BoostQ1. The cathode of the first boost diode BoostD1, the output terminal of the first normally closed relay NCR1, one end of the first capacitor C1, one end of the first sampling resistor, and the first positive electrode PE1 are all connected in a conductive manner. The negative output terminal of the first voltage doubler rectifier switching circuit CD1, the anode of the first buck diode BuckD1, the drain of the first boost switch BoostQ1, the other end of the first capacitor C1, and the first negative electrode NE1 are all connected in a conductive manner and grounded.

[0032] The second discharge circuit 200 includes a second voltage doubler rectifier switching circuit CD2, a second normally closed relay NCR2, a second buck switch BuckQ2, a second buck diode BuckD2, a second inductor L2, a second boost switch BoostQ2, a second boost diode BoostD2, a second capacitor C2, a second positive electrode PE2, a second negative electrode NE2, and a second sampling resistor R2; one end of the secondary winding of the transformer is connected to one input terminal of the second voltage doubler rectifier switching circuit CD2, and the other end of the secondary winding of the boost transformer ST1 is connected to the other input terminal of the second voltage doubler rectifier switching circuit CD2;

[0033] The positive output terminal of the second voltage doubler rectifier switching circuit CD2 is connected to the input terminal of the second normally closed relay NCR2 and the source of the second buck switch BuckQ2. The drain of the second buck switch BuckQ2 is connected to one end of the second inductor L2 and the cathode of the second buck diode BuckD2. The other end of the second inductor L2 is connected to the anode of the second boost diode BoostD2 and the source of the second boost switch BoostQ2. The cathode of the second boost diode BoostD2, the output terminal of the second normally closed relay NCR2, one end of the second capacitor C2, one end of the second sampling resistor, and the second positive electrode PE2 are all connected in a conductive manner. The negative output terminal of the second voltage doubler rectifier switching circuit CD2, the anode of the second buck diode BuckD2, the drain of the second boost switch BoostQ2, the other end of the second capacitor C2, and the second negative electrode NE2 are all connected in a conductive manner and grounded.

[0034] The first voltage doubler rectifier switching circuit CD1 consists of a first normally open relay NOR1, four rectifier diodes, and two voltage doubler capacitors. The channel of the first normally open relay NOR1 can control the output voltage of the first voltage doubler rectifier switching circuit CD1 to be one or two times.

[0035] The second voltage doubler rectifier switching circuit CD2 consists of a second normally open relay NOR2, four rectifier diodes, and two voltage doubler capacitors. The channel of the second normally open relay NOR2 can control the output voltage of the second voltage doubler rectifier switching circuit CD2 to be one or two times.

[0036] The stable discharge circuit of the electric flame stove also includes a control circuit. To reduce the breakdown voltage of the discharge circuit, this invention can also employ a high-temperature air dielectric thermal breakdown scheme or an initial plasma breakdown excitation scheme. Example 1

[0037] This embodiment uses two parallel sets of discharge circuits, 100 and 200, as an example. The principle is exactly the same when expanding to the Nth set. The entire machine uses only a single step-up transformer ST1 secondary winding to provide AC high voltage input to multiple discharge circuits. The DC circuits of each discharge circuit are mutually isolated and independently controlled, thereby solving the problems of voltage clamping, inability to break down simultaneously, and uneven current in parallel branches.

[0038] At startup, both the first normally open relay NOR1 and the second normally open relay NOR2 are turned on, and both sets of voltage doubler rectifier switching circuits operate in voltage doubler rectification mode (output voltage 2U). The control circuit outputs a turn-off signal, and the first buck switch BuckQ1, the first boost switch BoostQ1, the second buck switch BuckQ2, and the second boost switch BoostQ2 are all in the off state. The first normally closed relay NCR1 and the second normally closed relay NCR2 remain in the on state to pre-charge the arc. At this time, the voltage of all positive electrodes is 2U. Example 2

[0039] If one branch road is breached first while the other branch roads are not, such as Figure 3 As shown, taking the example of the first discharge circuit 100 breaking down first while the second discharge circuit 200 still does not break down:

[0040] The first normally open relay NOR1 quickly disconnects from the energized state, causing the first voltage doubler rectifier switching circuit CD1 to switch from a voltage doubler rectification mode to a voltage doubler rectification mode (the output voltage drops to voltage double U). The first normally closed relay NCR1 disconnects, and the first boost switch BoostQ1 remains off. At this time, the first buck switch BuckQ1 switches from the off state to the PWM conduction state, forming a Buck buck circuit with the first inductor L1 and the first buck diode BuckD1. This further limits and reduces the voltage of the voltage doubler bus (to about ½U), preventing the common ground potential from rising. Meanwhile, the first sampling resistor R1 collects the discharge current signal in real time, and the control circuit dynamically adjusts the duty cycle of the first buck switch BuckQ1 based on this signal.

[0041] During this process, the second discharge circuit 200 operates as follows: no current flows through the second sampling resistor R2, and the control circuit identifies it as not being broken down. The second normally open relay NOR2 remains energized and conducting. The second voltage doubler rectifier switching circuit CD2 maintains the voltage doubler rectification mode (output voltage remains at 2U). The second normally closed relay NCR2 is disconnected. The second buck switch BuckQ2 is normally open and has no PWM drive signal. The second boost switch BoostQ2 changes from the cutoff state to the PWM conduction state. Together with the second inductor L2 and the second boost diode BoostD2, they form a complete boost circuit. The second inductor L2 serves as the core energy storage component of the Boost circuit. When it is turned on, it stores sufficient electromagnetic energy and releases a high induced voltage when it is turned off. Through the high-frequency cycle of energy storage and release, the voltage is boosted from 2U to 4U, meeting the higher breakdown voltage requirements of the non-breakdown branch. The second capacitor C2 further boosts the voltage of the doubler bus (to about 4U). Its main function is to store the 4U high-voltage energy output by the Boost circuit and smooth the high-voltage pulsation, so that the voltage between the second positive electrode PE2 and the second negative electrode NE2 is stabilized above the breakdown threshold, providing energy guarantee for rapid breakdown.

[0042] This stage utilizes differentiated control based on whether the branch circuit has experienced voltage reduction (1U→½U) or non-voltage-prone branch circuit has experienced voltage increase (2U→4U).

[0043] The voltage of the broken-down branch is reduced to ½U by switching with a double voltage and buck switching, which avoids the rise of the common ground potential caused by large current, completely eliminates the potential interference to the unbroken branch, and solves the voltage clamping problem of traditional solutions.

[0044] The non-breakdown branch uses a double voltage retainer and a boost voltage to increase the voltage to 4U, breaking through its own breakdown voltage threshold. This ensures that even if some branches break down first, the remaining branches can still break down independently, achieving 100% arc initiation for all branches. Example 3

[0045] After startup, once all discharge branches have completed breakdown and entered a stable plasma discharge state, the common ground potential has been raised to a stable operating potential by the discharge currents of all branches. At this point, the entire unit enters a steady-state discharge phase. The control circuit detects that the discharge currents of all branches have been stably established and uniformly controls all discharge circuits to switch to a double-voltage rectifier direct output working mode. That is, all normally open and normally closed relays remain on, and all buck and boost switching transistors are turned off by the control circuit during the steady-state discharge phase, and are all in the off state. Under the double-voltage high-voltage drive, all positive and negative electrodes maintain a stable plasma flame. All electrodes share the raised common ground potential, and the potentials are balanced and consistent. There is no longer voltage clamping or current pulling between branches, achieving synchronous, equal voltage, equal current, and stable discharge of multiple branches. Example 4

[0046] This circuit can adaptively connect to 110V~120V or 220V~240V AC mains power. The control circuit detects the input AC mains amplitude and uniformly configures each group of voltage doubler rectifier switching circuits to achieve a stable 2U high voltage output under different AC mains power conditions, and ultimately enters the same steady-state discharge mode.

[0047] When connected to 220V~240V mains power, the control circuit detects that the mains voltage is in the high voltage range and controls each discharge circuit to work. Its working principle is the same as that of Examples 1, 2 and 3.

[0048] When connected to 110V~120V mains power, the input voltage is low, and the required 2U high voltage cannot be achieved by voltage doubler rectification alone. The control circuit controls all boost switching transistors to participate in PWM boost operation. The principle of all discharge circuits is the same as the working principle of the second discharge circuit 200 in Example 2, and finally achieves the same voltage equalization, current equalization, and stable plasma discharge effect as the 220V input condition.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A stable discharge circuit for an electric flame stove, characterized in that, include: A single step-up transformer and multiple sets of discharge circuits; the multiple sets of discharge circuits include a first discharge circuit, a second discharge circuit, and an Nth discharge circuit connected in parallel; wherein, the circuit structure of each set of discharge circuits is the same; The first discharge circuit includes a first voltage doubler rectifier switching circuit, a first normally closed relay, a first buck switch, a first buck diode, a first inductor, a first boost switch, a first boost diode, a first capacitor, a first positive electrode, a first negative electrode, and a first sampling resistor; one end of the secondary winding of the boost transformer is connected to one input terminal of the first voltage doubler rectifier switching circuit, and the other end of the secondary winding of the boost transformer is connected to the other input terminal of the first voltage doubler rectifier switching circuit; The positive output terminal of the first voltage doubler rectifier switching circuit is connected to the input terminal of the first normally closed relay and the source of the first buck switch. The drain of the first buck switch is connected to one end of the first inductor and the cathode of the first buck diode. The other end of the first inductor is connected to the anode of the first boost diode and the source of the first boost switch. The cathode of the first boost diode, the output terminal of the first normally closed relay, one end of the first capacitor, one end of the first sampling resistor, and the first positive electrode are all electrically connected. The negative output terminal of the first voltage doubler rectifier switching circuit, the anode of the first buck diode, the drain of the first boost switch, the other end of the first capacitor, and the first negative electrode are all electrically connected and grounded. The first voltage doubler rectifier switching circuit consists of a first normally open relay, four rectifier diodes, and two voltage doubler capacitors. The channel of the first normally open relay can control the output voltage of the first voltage doubler rectifier switching circuit to be one or two times.

2. The stable discharge circuit of the electric flame stove according to claim 1, characterized in that, It also includes control circuitry.

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