A capacitive wireless charging portable gas detector

Abstract

This invention proposes a capacitive wireless charging portable gas detector, comprising a charging base that matches the portable gas detector. The charging base contains a power supply circuit, a control circuit, and a first coupling electrode plate. Both the power supply circuit and the control circuit are connected to the first coupling electrode plate. The control circuit generates a high-frequency PWM signal as a drive signal for the first coupling electrode plate. The portable gas detector contains a second coupling electrode plate, a charging circuit, and a battery. The second coupling electrode plate matches the first coupling electrode plate, and the closer-proximity second coupling electrode plate forms a capacitor structure with the first coupling electrode plate. The second coupling electrode plate induces a charge and is connected to the battery through the charging circuit. This invention utilizes coupling electrode plates instead of inductors, eliminating the need for large internal inductance. The coupling electrode plates inside the portable gas detector are separate and cannot form a capacitor, reducing the difficulty of intrinsically safe explosion-proof design, improving device safety, and extending the service life of the portable instrument.

Description

Technical Field

[0001] This invention relates to the technical field of gas detectors, and more particularly to a capacitive wireless charging portable gas detector. Background Technology

[0002] In chemical industrial work sites, the presence of hazardous gases necessitates that workers wear portable gas detectors. These detectors are widely used for industrial environmental inspections. Portable gas detectors offer gas detection capabilities and are small and easy to carry, playing a crucial role in protecting personnel safety. Powered by lithium batteries, these detectors require regular and timely charging; otherwise, they will cease operation.

[0003] Current portable gas detectors use plug-in charging, contact electrode charging, or wireless coil charging. All of these charging methods have significant drawbacks.

[0004] Plug-in or contact-type electrode charging methods inevitably require an outlet in the device's casing, leading to incomplete sealing. Currently, portable gas detectors generally require an IP68 waterproof and dustproof rating. Once the casing has an opening, the sealing difficulty increases significantly. Achieving a proper seal necessitates a very high level of precision in the fit between the casing and the charging port, increasing manufacturing complexity and the probability of malfunctions. Traditional charging methods also expose the charging electrodes to static electricity, which can damage internal components through direct contact discharge. Exposed electrodes are also easily damaged or corroded, drastically shortening the device's lifespan.

[0005] Coil-coupled charging overcomes some of the shortcomings of plug-in and contact charging methods, but it also introduces some new problems. The first is that coil-coupled wireless charging has requirements on the inductance of the coil. If the inductance is too small, the charging efficiency is very low; if the inductance is too large, it will increase the difficulty of intrinsically safe explosion-proof design of portable gas detectors (intrinsically safe explosion-proof design requires the circuit inductance to be less than a certain value).

[0006] Utility model patent application number 201821017577.3 discloses a portable gas detection device, including an explosion-proof wireless charging device. The device includes a charging base body, which comprises a support base and a support back plate fixedly disposed on the back of the support base. A wireless transmitting coil and a control circuit board connected to the wireless transmitting coil are disposed within the support base. A groove for placing the portable gas detector is provided on the top surface of the support base. This patent allows the portable gas detector to be wirelessly charged by placing it inside the charging base via the wireless coil, eliminating the need for exposed metal charging ports on the portable gas detector and ensuring normal charging. However, inductive coil coupling has the following drawbacks: 1. Low efficiency: Coil coupling is magnetic field coupling. The charger must convert the battery into a magnetic field before transferring energy to the coil of the device being charged. Energy loss occurs during this conversion process. The alternating magnetic field creates eddy currents in the coil conductor, causing the coil to heat up and resulting in energy loss. 2. Severe external radiation during charging: Since the coil has no magnetic core, the magnetic field is unconstrained, leading to more severe external radiation. This may interfere with the normal operation of other devices and also cause energy loss. 3. Susceptibility to interference from metal objects: If a metal object approaches the coil during charging, it will affect the distribution of the magnetic field, thus affecting the coil's operational stability, leading to reduced charging efficiency or even charging failure. 4. High requirements for coil manufacturing processes: To achieve better coupling, the resonant frequencies of the two coils must be similar, ideally identical. This is difficult to achieve, and it is generally hard to achieve completely identical parameters, making it difficult to improve the charging efficiency of coil coupling. 5. An inductor is an inductor. Industrial portable instruments require intrinsically safe explosion-proof protection. If there is a large inductance inside the instrument, it will damage the explosion-proof structure, increasing the probability of a safety accident. Summary of the Invention

[0007] To address the technical problems of existing gas detectors requiring a pre-existing charging interface on the housing and poor sealing, this invention proposes a capacitive wireless charging portable gas detector. It uses capacitive coupling for charging, eliminating the need for exposed charging electrodes and openings in the housing, thus ensuring the integrity of the housing, reducing the difficulty of housing sealing design, and easily achieving an IP68 protection rating. Furthermore, the absence of charging electrode contacts eliminates issues such as poor contact due to corrosion.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: A capacitive wireless charging portable gas detector includes a charging base that is matched with the portable gas detector. The charging base contains a power supply circuit, a control circuit, and a first coupling electrode plate. Both the power supply circuit and the control circuit are connected to the first coupling electrode plate. The control circuit generates a high-frequency PWM signal as a driving signal for the first coupling electrode plate. The portable gas detector contains a second coupling electrode plate, a charging circuit, and a battery. The second coupling electrode plate is matched with the first coupling electrode plate. The second coupling electrode plate that is closer to the first coupling electrode plate forms a capacitor structure with the first coupling electrode plate. The second coupling electrode plate induces a charge and is connected to the battery through the charging circuit.

[0009] Preferably, both the control circuit and the power supply circuit are connected to the full-bridge drive circuit, which is connected to the first coupling electrode plate. The high-frequency PWM signal output by the control circuit passes through the full-bridge drive circuit to give the first coupling electrode plate an electric field with alternating polarity. The first coupling electrode plate couples the electric field to the second coupling electrode plate to generate an induced voltage, which is provided to the charging circuit to charge the battery.

[0010] Preferably, there are two of each of the first and second coupling electrode plates. The two first coupling electrode plates are respectively connected to the positive and negative terminals of the power supply circuit, and the two second coupling electrode plates are respectively connected to the positive and negative terminals of the charging circuit.

[0011] Preferably, the two second coupling electrode plates are connected to the charging circuit through a sorting and filtering circuit.

[0012] Preferably, the power supply circuit includes a high-voltage DC power supply circuit and a low-voltage DC power supply circuit. The high-voltage DC power supply circuit is connected to a 220V mains power supply. The positive and negative terminals of the high-voltage DC power supply circuit are respectively connected to a full-bridge drive circuit. The high-voltage DC power supply circuit and the low-voltage DC power supply circuit are connected together. The low-voltage DC power supply circuit is connected to a control circuit.

[0013] Preferably, the full-bridge drive circuit includes a first MOSFET, a second MOSFET, a fourth MOSFET, and a third MOSFET connected in a bridge configuration. All three MOSFETs are connected to the control circuit. The midpoint between the first and second MOSFETs is connected to plate A of the first coupling electrode plate, and the midpoint between the fourth and third MOSFETs is connected to plate B of the first coupling electrode plate. The midpoint between the first and third MOSFETs is connected to the positive terminal of the high-voltage DC power supply circuit of the power supply circuit, and the midpoint between the second and fourth MOSFETs is connected to the negative terminal of the high-voltage DC power supply circuit of the power supply circuit.

[0014] Preferably, the PWM signal output by the control circuit generates a high-frequency PWM signal through the full-bridge drive circuit. When the PWM signal output is high, the first and fourth MOSFETs in the full-bridge drive circuit are turned on, while the second and third MOSFETs are turned off. Plate A of the first coupling electrode is connected to the positive terminal of the high-voltage DC power supply circuit and becomes positively charged. Plate B of the first coupling electrode is connected to the negative terminal of the high-voltage DC power supply circuit and becomes negatively charged. Plate C of the second coupling electrode, which is closer to the first coupling electrode, forms the two poles of a capacitor with Plate A of the first coupling electrode, and negative charge is induced on Plate C of the second coupling electrode. Plate B of the first coupling electrode, which is closer to the second coupling electrode, forms the two poles of a capacitor with Plate D of the second coupling electrode, and positive charge is induced on Plate D of the second coupling electrode. A positive voltage is generated between Plate D and Plate C of the second coupling electrode.

[0015] When the PWM signal output is low, the second and third MOSFETs in the full-bridge drive circuit are turned on, while the first and second MOSFETs are turned off. Plate A of the first coupling electrode is connected to the negative terminal of the high-voltage DC power supply circuit and becomes negatively charged. Plate B of the first coupling electrode is connected to the positive terminal of the high-voltage DC power supply circuit and becomes positively charged. Plate C of the second coupling electrode, which is closer to the first coupling electrode, forms the two poles of a capacitor with plate A of the first coupling electrode, and positive charge is induced on plate C of the second coupling electrode. Plate B of the first coupling electrode, which is closer to the second coupling electrode, forms the two poles of a capacitor with plate D of the second coupling electrode, and negative charge is induced on plate D of the second coupling electrode. A negative voltage will be generated between plates D and C of the second coupling electrode.

[0016] This process repeats continuously, with the D and C plates of the second coupling electrode plate constantly generating alternating voltages. After passing through a rectifier and filter circuit, these voltages are converted into DC voltages, which are then used to charge the battery through a charging circuit.

[0017] Preferably, the rectifier-filter circuit includes a rectifier circuit and a filter circuit. The input terminal of the rectifier circuit is connected to two second coupling electrode plates, and the output terminal of the rectifier circuit is connected to the charging circuit through the filter circuit. The rectifier circuit converts the AC voltage transmitted from the second coupling electrode plates into a DC voltage. The filter circuit is used to filter the rectified DC voltage.

[0018] Preferably, the rectifier circuit is a rectifier bridge, with its two input terminals connected to two second coupling electrode plates, and its two output terminals connected to the positive and negative terminals of the charging circuit after being processed by a filter circuit; the filter circuit uses a filter capacitor.

[0019] Preferably, the charging base is further provided with a sensing circuit, which is connected to the low-voltage DC power supply circuit of the power supply circuit and the control circuit; the sensing circuit includes a photosensitive sensor, which is fixed on the charging base.

[0020] Compared with existing technologies, the advantages of this invention are as follows: This invention creatively uses capacitive wireless charging to charge portable gas detectors, eliminating the need to expose charging electrodes. The shell is closed, ensuring its integrity and easily achieving an IP68 protection rating, reducing the difficulty of shell sealing design. Without charging electrode contacts, there are no issues such as poor contact due to corrosion. The charging circuit of this invention consists of two parts: one part is in the charging base, which includes a power supply circuit, a control circuit, and a full-bridge drive circuit to drive the coupling electrode plate, causing it to generate an electric field with continuously changing polarity; the other part is inside the portable gas detector, including the coupling electrode plate, a rectifier circuit, a filter circuit, a charging circuit, and a battery. During charging, the portable gas detector is placed on the charging base. The charging base senses the device and activates the high-frequency signal generation circuit. The alternating electric field couples through the electrode plate of the charging base to the coupling electrode plate inside the portable gas detector, energizing the coupling electrode plate and generating electrical energy. This energy is then rectified, regulated, and charged through the charging management circuit to charge the battery of the portable gas detector.

[0021] This invention utilizes coupling electrode plates to replace inductors, eliminating the need for large inductors within the device. The coupling electrode plates inside the portable gas detector are separate and cannot form a capacitor, thus eliminating both large inductors and large capacitors within the portable gas detector. This reduces the difficulty of intrinsically safe explosion-proof design and further improves device safety. The absence of wear and tear on connectors extends the lifespan of the portable instrument, making use and maintenance more convenient.

[0022] This invention, capacitive coupling charging, overcomes the shortcomings of coil coupling charging: 1. Capacitive coupling is more efficient. Energy is transferred through an electric field, eliminating one stage of energy conversion compared to magnetic field coupling, thus reducing efficiency loss. 2. Eddy currents are not formed in the electric field during capacitive coupling, further reducing energy loss. 3. Capacitive coupling occurs only between two coupling electrode plates, with no external radiation, resulting in minimal energy loss and interference. 4. Capacitive coupling is a closed coupling method, minimizing external radiation and the proximity of external metals does not affect charging. 5. Capacitive electrode plates are simple to manufacture, requiring only approximately equal areas, leading to low production costs and a simple process. 6. Capacitive coupling only forms a capacitor when the two pairs of coupling electrode plates are close together. When the portable instrument leaves the charging base, the capacitance between the coupling electrode plates inside the charging base and the electrode plates inside the instrument disappears. Since the two electrode plates inside the portable instrument are separate, no capacitance is formed, thus preserving the inherent safety characteristics of the portable instrument and ensuring its safe use. Attached Figure Description

[0023] 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.

[0024] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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] like Figure 1As shown, a capacitive wireless charging portable gas detector includes a charging base that matches the portable gas detector, which can be inserted into the charging base. The charging base contains a power supply circuit, a control circuit, and a first coupling electrode plate. Both the power supply circuit and the control circuit are connected to the first coupling electrode plate. The power supply circuit provides energy to the first coupling electrode plate, and the MCU in the control circuit generates a high-frequency PWM signal as a drive signal for the first coupling electrode plate. The portable gas detector contains a second coupling electrode plate, a charging circuit, and a battery. The second coupling electrode plate matches the first coupling electrode plate, and both first and second coupling electrode plates are provided. The two first coupling electrode plates are connected to the positive and negative terminals of the power supply circuit, respectively, and the two second coupling electrode plates are connected to the positive and negative terminals of the charging circuit, respectively. The first coupling electrode plate provides the electric field required for charging the second coupling electrode plate. The second coupling electrode plate receives energy from the first coupling electrode plate in the charging base and transfers the energy to the rectifier circuit. The second coupling electrode plate is connected to the battery through the charging circuit, which charges the battery, thereby transferring electrical energy to the battery of the portable gas detector, achieving wireless charging. Batteries are used to store electrical energy.

[0027] The high-frequency PWM signal output by the MCU in the control circuit is driven by the full-bridge drive circuit to make the first coupling electrode plate of the charging base have an alternating polarity electric field. The first coupling electrode plate couples the electric field to the second coupling electrode plate built into the portable gas detector, causing the built-in capacitive coupling electrode plate of the portable gas detector to generate an induced voltage. After passing through the rectification and filtering circuit, the voltage is supplied to the charging circuit to charge the battery of the portable gas detector.

[0028] The first coupling electrode plate is located above the charging base. When the portable instrument is placed on the charging base, the second coupling electrode plate inside the portable instrument will be in close contact with the first coupling electrode plate. Due to the close distance between the first and second coupling electrode plates, a capacitor structure is formed between them. The present invention uses the capacitor formed by the first and second coupling electrode plates when they are close to each other to transfer energy and charge the portable instrument.

[0029] Both the control circuit and the power supply circuit are connected to the full-bridge drive circuit. The power supply circuit provides high-voltage DC power to the full-bridge drive circuit. The PWM signal output by the control circuit generates a high-frequency PWM signal through the full-bridge drive circuit. The full-bridge drive circuit consists of four MOSFETs. Under the control of the PWM signal output by the MCU in the control circuit, when the PWM signal outputs a high level, MOSFETs 1 and 4 in the full-bridge drive circuit are turned on, while MOSFETs 2 and 3 are turned off. At this time, plate A of the first coupling electrode is connected to the positive terminal of the high-voltage power supply and becomes positively charged. Plate B of the first coupling electrode is connected to the negative terminal of the high-voltage power supply and becomes negatively charged. Since plate C of the second coupling electrode is very close to plate A of the first coupling electrode, the two plates form the two poles of a capacitor. When plate A of the first coupling electrode is positively charged, plate C of the second coupling electrode will be induced with a negative charge. The B plate of the first coupling electrode plate and the D plate of the second coupling electrode plate are very close to each other, forming the two poles of a capacitor. When the B plate of the first coupling electrode plate is negatively charged, a positive charge will be induced on the D plate of the second coupling electrode plate. In this way, the D plate and C plate of the second coupling electrode plate are positively charged and negatively charged respectively, and a positive voltage will be generated between the D plate and the C plate.

[0030] When the PWM signal output is low, MOSFETs 2 and 3 in the full-bridge drive circuit are turned on, while MOSFETs 1 and 4 are turned off. At this time, plate A of the first coupling electrode is connected to the negative terminal of the high-voltage power supply and becomes negatively charged. Plate B of the first coupling electrode is connected to the positive terminal of the high-voltage power supply and becomes positively charged. Since plate C of the second coupling electrode is very close to plate A of the first coupling electrode, the two plates form the two poles of a capacitor. When plate A of the first coupling electrode is negatively charged, plate C of the second coupling electrode will be positively charged. Plate B of the first coupling electrode is very close to plate D of the second coupling electrode, and the two plates form the two poles of a capacitor. When plate B of the first coupling electrode is positively charged, it will be negatively charged on plate D of the second coupling electrode. Thus, plates D and C of the second coupling electrode are negatively charged and positively charged respectively, resulting in a negative voltage between plates D and C.

[0031] This process repeats continuously, so that the D and C plates of the second coupling electrode plate continuously generate alternating voltages, which are then converted into DC voltages by the rectifier bridge and supplied to the charging control circuit to charge the battery.

[0032] The charging dock also includes a sensing circuit connected to the control circuit. The sensing circuit includes a photosensor fixed to the charging dock. When the portable device is placed on the charging dock, the light is blocked. The MCU in the control circuit detects the signal change from the photosensor, confirming that the portable device is on the charging dock, and then starts charging. When the portable device is lifted, the photosensor detects light, and the MCU in the control circuit detects the signal, stopping charging. This automatically determines whether a device is being charged on the charging dock, thus controlling the start and stop of charging and avoiding unnecessary energy loss.

[0033] The power supply circuit includes a high-voltage DC power supply circuit and a low-voltage DC power supply circuit. The high-voltage DC power supply circuit is connected to 220V AC mains power. Its positive and negative terminals are connected to the positive and negative terminals of the full-bridge drive circuit, respectively. The high-voltage and low-voltage DC power supply circuits are connected, and the low-voltage DC power supply circuit is connected to both the control circuit and the sensing circuit, providing power to both. The high-voltage DC power supply provides power to the full-bridge drive circuit, allowing for a higher voltage to the first coupling electrode plate, generating a stronger electric field and better transferring energy to the second coupling electrode plate. The controller circuit operates at a relatively low voltage and cannot be directly powered by the high-voltage DC power supply. The low-voltage DC power supply circuit acts as a power conversion circuit, converting the high-voltage power supply into a voltage suitable for the control circuit.

[0034] The second coupling electrode plate inside the portable gas detector is connected to the charging circuit via a rectifier-filter circuit. The two ends of the rectifier-filter circuit are connected to the two second coupling electrode plates respectively. The rectifier-filter circuit includes a rectifier circuit and a filter circuit. The rectifier circuit converts the AC voltage transmitted from the second coupling electrode plates into a DC voltage. The filter circuit filters the rectified voltage to make it more stable. The rectifier circuit is a rectifier bridge. The two input terminals of the rectifier bridge are connected to the two second coupling electrode plates respectively, and the two output terminals of the rectifier bridge, after being processed by the filter circuit, are connected to the positive and negative terminals of the charging circuit respectively.

[0035] The filtering circuit uses a filter capacitor to further reduce fluctuations in the rectified DC voltage, making the voltage more stable and thus more conducive to the operation of the charging circuit. The filtered voltage is then supplied to the charging circuit, which employs different charging strategies based on the current battery voltage. The presence of the charging circuit prevents overcharging and excessive charging current, ensuring safe and reliable charging.

[0036] Inside the charging base, a high-voltage DC power supply circuit converts AC 220V power into a higher voltage (e.g., 24V) high-voltage DC power supply, which is then supplied to the full-bridge circuit and the low-voltage DC power supply circuit. The low-voltage DC power supply circuit converts the high-voltage DC power into low-voltage DC power for use by the control circuit and the sensing circuit. When the sensing circuit detects that the portable gas detector is placed on the charging base, the control circuit outputs a high-frequency PWM signal (tens of kilohertz) to the full-bridge drive circuit, driving the full-bridge drive circuit to generate an alternating electric field on the first coupling electrode plate connected to the full-bridge drive circuit. This alternating electric field induces an alternating voltage on the second coupling electrode plate inside the portable instrument. This alternating voltage is rectified by a rectifier bridge connected to the second coupling electrode plate, becoming a DC voltage. After being filtered by a filter circuit, it is supplied to the charging circuit, which controls the charging of the portable instrument's battery.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A capacitive wireless charging portable gas detector, characterized in that, The application relates to a charging base matched with a portable gas detector, wherein the charging base is internally provided with a power supply circuit, a control circuit and a first coupling electrode plate, the power supply circuit and the control circuit are connected with the first coupling electrode plate, the control circuit generates a high-frequency PWM signal as a driving signal of the first coupling electrode plate; the portable gas detector is internally provided with a second coupling electrode plate, a charging circuit and a battery, the second coupling electrode plate is matched with the first coupling electrode plate, the second coupling electrode plate and the first coupling electrode plate form a two-pole structure of a capacitor at a close distance, the second coupling electrode plate generates electric charges, and the second coupling electrode plate is connected with the battery through the charging circuit. The control circuit and the power supply circuit are connected with a full-bridge driving circuit, the full-bridge driving circuit is connected with the first coupling electrode plate, the high-frequency PWM signal output by the control circuit passes through the full-bridge driving circuit to make the first coupling electrode plate have a polarity-alternating electric field, the first coupling electrode plate couples the electric field to the second coupling electrode plate to generate an induced voltage, the induced voltage is provided to the charging circuit to charge the battery. The power supply circuit comprises a high-voltage direct-current power supply circuit and a low-voltage direct-current power supply circuit, the high-voltage direct-current power supply circuit is connected with 220V commercial power, the power positive pole and the power negative pole of the high-voltage direct-current power supply circuit are respectively connected with the full-bridge driving circuit, the high-voltage direct-current power supply circuit is connected with the low-voltage direct-current power supply circuit, and the low-voltage direct-current power supply circuit is connected with the control circuit. The full-bridge driving circuit comprises a first MOS tube, a second MOS tube, a third MOS tube and a fourth MOS tube connected in a bridge mode, the first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube are connected with the control circuit, the midpoint between the first MOS tube and the second MOS tube is connected with an A plate of the first coupling electrode plate, the midpoint between the fourth MOS tube and the third MOS tube is connected with a B plate of the first coupling electrode plate, the midpoint between the first MOS tube and the third MOS tube is connected with the power positive pole output by the high-voltage direct-current power supply circuit of the power supply circuit, and the midpoint between the second MOS tube and the fourth MOS tube is connected with the power negative pole output by the high-voltage direct-current power supply circuit of the power supply circuit.

2. The capacitive wireless charging portable gas detector of claim 1, wherein, The number of the first coupling electrode plates and the second coupling electrode plates is two, the two first coupling electrode plates are respectively connected with the power positive pole and the power negative pole of the power supply circuit, and the two second coupling electrode plates are respectively connected with the positive pole and the negative pole of the charging circuit.

3. The capacitive wireless charging portable gas detector of claim 2, wherein, The two second coupling electrode plates are connected with the charging circuit through a rectification filtering circuit.

4. The capacitive wireless charging portable gas detector according to any of claims 1-3, characterized in that, The PWM signal output by the control circuit generates a high-frequency PWM signal through the full-bridge driving circuit; when the PWM signal output is high, the first MOS tube and the fourth MOS tube in the full-bridge driving circuit are turned on, the second MOS tube and the third MOS tube are turned off, the A plate of the first coupling electrode plate is connected to the positive pole of the high-voltage DC power supply circuit and carries positive electricity, the B plate of the first coupling electrode plate is connected to the negative pole of the high-voltage DC power supply circuit and carries negative electricity; the C plate of the second coupling electrode plate close to the A plate of the first coupling electrode plate forms two poles of a capacitor, and the C plate of the second coupling electrode plate induces negative electricity; the D plate of the second coupling electrode plate close to the B plate of the first coupling electrode plate forms two poles of a capacitor, and the D plate of the second coupling electrode plate induces positive electricity, and a positive voltage is generated between the D plate and the C plate of the second coupling electrode plate; When the PWM signal output is low, the second MOS tube and the third MOS tube in the full-bridge driving circuit are turned on, the first MOS tube and the second MOS tube are turned off, the A plate of the first coupling electrode plate is connected to the negative pole of the high-voltage DC power supply circuit and carries negative electricity, the B plate of the first coupling electrode plate is connected to the positive pole of the high-voltage DC power supply circuit and carries positive electricity; the C plate of the second coupling electrode plate close to the A plate of the first coupling electrode plate forms two poles of a capacitor, and the C plate of the second coupling electrode plate induces positive electricity; the D plate of the second coupling electrode plate close to the B plate of the first coupling electrode plate forms two poles of a capacitor, and the D plate of the second coupling electrode plate induces negative electricity, and a negative voltage is generated between the D plate and the C plate of the second coupling electrode plate; The D plate and the C plate of the second coupling electrode plate continuously generate alternating voltages, which are converted into direct-current voltages through the rectification and filtering circuit, and the battery is charged through the charging circuit.

5. The capacitive wireless charging portable gas detector of claim 4, wherein, The rectification and filtering circuit comprises a rectification circuit and a filtering circuit, the input end of the rectification circuit is connected to the two second coupling electrode plates, and the output end of the rectification circuit is connected to the charging circuit through the filtering circuit; the rectification circuit converts the alternating voltage transmitted by the second coupling electrode plates into a direct-current voltage; and the filtering circuit is used for filtering the rectified direct-current voltage.

6. The capacitive wireless charging portable gas detector of claim 5, wherein, The rectification circuit is a rectification bridge, the two input ends of the rectification bridge are respectively connected to the two second coupling electrode plates, and the two output ends of the rectification bridge are respectively connected to the positive pole and the negative pole of the charging circuit after being processed by the filtering circuit; and the filtering circuit adopts a filtering capacitor.

7. The capacitive wireless charging portable gas detector according to any one of claims 1, 5, 6, wherein, The charging base is further provided with an induction circuit, the induction circuit is connected to the low-voltage DC power supply circuit of the power supply circuit and the control circuit; and the induction circuit comprises a photosensitive sensor fixed on the charging base.

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