Methods, apparatus, equipment and media for corona discharge stability control in aerosol concentration detection

Abstract

This application discloses a method, apparatus, device, and medium for controlling the stability of corona discharge in aerosol concentration detection. The method involves setting up a ring electrode comprising a first cavity and a second cavity arranged coaxially. A corona needle is coaxially located in the first cavity with its tip adjacent to the second cavity. A control chip uses a PWM signal to convert a low-voltage DC power supply signal into a 2kV±5% high voltage, which is then applied between the corona needle and the ring electrode. A total compensation control quantity is obtained by combining a first compensation control quantity obtained from compensating the discharge current of the corona needle with a second compensation control quantity obtained from compensating environmental parameters. This total control quantity is then used to adjust the duty cycle of the PWM signal of the control chip. Embodiments of this invention exhibit strong current stability, good environmental adaptability, low discharge voltage, and a long service life for the corona needle.

Description

Technical Field

[0001] This application belongs to the field of aerosol detection, and in particular to a method, apparatus, equipment and medium for controlling the stability of corona discharge for aerosol concentration detection. Background Technology

[0002] The measurement of aerosol particulate matter concentration and particle size can be based on the principle of charged diffusion detection, which involves technologies such as corona discharge, diffusion charging, electromigration sieving, and Faraday cup electrostatic induction.

[0003] The basic principle of charged diffusion detection is as follows: After clean air enters the charging module, it is ionized by the positive high voltage discharge generated by the corona needle. In the charging region (mixing region), positive ions attach to the particulate matter to be tested in the sample gas. After entering the ion separation module, the charged particles are subjected to the combined action of the electric field and the flow field, causing different charged particles to have different flight paths, thereby achieving the effect of screening particles of different sizes. Large particles exceeding the threshold can enter the Faraday cup in the subsequent sensor module to collect the charge of the charged particles. Then, the generated micro-current value is detected by the operational amplifier circuit, and finally the number concentration of particles is obtained by inversion.

[0004] In summary, corona discharge is a crucial step, and whether a stable discharge current can be generated has a significant impact on the final measurement results.

[0005] The principle of corona discharge is that near a pointed electrode with a relatively small radius of curvature, the strong electric field generated between the electrode plate and the tip of the discharge needle exceeds the ionization field of the gas, thus causing ionization of the dielectric gas flowing between them. The intensity of the corona current mainly depends on the shape of the electrodes, the magnitude of the voltage applied between the two electrodes, the properties and density of the electrolyte gas, and other conditions.

[0006] Under positive polarity corona discharge, once the applied voltage reaches the corona initiation voltage, free electrons in the discharge region begin to move towards the discharge needle under the influence of the electric field, colliding with neutral gas molecules near the tip of the needle. New electrons and ions are ionized in the corona region. These newly ionized particles undergo further ionization under the influence of the electric field, forming an electron avalanche. When the electron avalanche is particularly intense, a large amount of plasma is generated in the anode discharge needle. The ionized electrons collide with gas molecules to form negative ions. Under the influence of the electric field and the gas flow entering the corona region, the negative ions move towards the discharge needle, while the positive ions flow out from the ground electrode plate into the mixing region, achieving particulate charging—that is, the combination of particulate matter and ions.

[0007] The electric field condition for ionizing air molecules is an extremely high electric field strength near the needle tip. This is achieved through the curvature effect of the needle tip, which leads to a concentration of local field strength. When the electric field strength exceeds the air breakdown threshold (approximately 30 kV / cm), impact ionization is triggered. Therefore, generally speaking, the discharge voltage needs to be tens to hundreds of kV (e.g., above 20 kV to 100 kV), and the discharge current needs to be tens of μA to several mA.

[0008] However, the larger the discharge current, the more obvious the etching of the corona needle becomes. A large number of ions bombard the surface of the corona needle under the action of the electric field. Under long-term action, the surface will become rough, with pits and spots appearing, resulting in a dispersed electric field distribution, which affects the discharge stability and the life of the corona needle.

[0009] Excessive voltage will cause the electric field strength to extend beyond the needle tip to the entire gap, eventually meeting the breakdown conditions of the entire air gap and forming a low-resistance spark channel. This will leave severe ablation pits on the needle tip and the other electrode, or even melt the needle tip directly.

[0010] The discharge current determines the rate of ion concentration generated by corona discharge, and the ionization process of air is easily affected by environmental factors and changes in needle characteristics. Therefore, current technologies that rely solely on circuit characteristics for PID control do not meet design requirements, resulting in high current noise and even abnormal discharge. Summary of the Invention

[0011] The purpose of this application is to provide a method, apparatus, device, and medium for controlling the stability of corona discharge in aerosol concentration detection, in order to solve the technical problem that the quantity and concentration of particulate matter obtained are unstable due to the unstable discharge current in existing aerosol concentration detection equipment.

[0012] A first aspect of this application provides a corona discharge stability control device for aerosol concentration detection, the device comprising:

[0013] The ring electrode includes a long and narrow first cavity arranged coaxially and a second cavity that is shorter and wider than the first cavity. The corona needle is coaxially located in the first cavity and the tip of the corona needle is located in the first cavity near the second cavity. A first entrance is provided in the first cavity away from the second cavity, and the distance between the first entrance and the needle tip is greater than 5 times the inner diameter of the first cavity.

[0014] A clean air duct, connected to the first inlet, is used to introduce clean air into the first cavity;

[0015] A charged region is arranged on the other side of the second cavity, relative to the first cavity, and the volume of the charged region is larger than that of the second cavity; the charged region is connected to a smoke outlet pipe;

[0016] The flue gas pipeline to be tested is arranged on the other side of the charged region, relative to the second cavity;

[0017] The circuit module uses a control chip to control the low-voltage DC power signal through a half-bridge drive, LC resonance, transformer, and voltage doubler rectifier to convert it into high voltage and apply it between the corona needle and the ring electrode. It also collects the discharge current of the corona needle, the temperature, humidity and air pressure of the device.

[0018] The control module is used to obtain a first compensation control quantity by performing compensation control on the discharge current of the corona needle using a compensation algorithm, and to obtain a second compensation control quantity by performing compensation control on temperature, humidity and air pressure. The first compensation control quantity and the second supplementary control quantity are combined to obtain a total compensation control quantity, and the duty cycle of the PWM signal of the control chip is adjusted through the total control quantity.

[0019] Preferably, the diameter of the corona needle is 0.4mm to 0.6mm.

[0020] Preferably, the corona needle is made of a tungsten-lanthanum alloy consisting of a tungsten matrix doped with 1.2% to 1.8% lanthanum oxide.

[0021] Preferably, the lanthanum oxide content in the tungsten-lanthanum alloy is 1.5%.

[0022] Preferably, the ring electrode is made of stainless steel.

[0023] Preferably, the diameter of the clean air duct is the same as the diameter of the first cavity.

[0024] Preferably, the charged region is cylindrical, and the second cavity and the flue gas pipeline to be tested are both perpendicular to the axis of the charged region.

[0025] Preferably, the space of the charged region is 2-5 times that of the second cavity.

[0026] Preferably, the diameter of the charged region is larger than the diameter of the second cavity and the flue gas pipeline to be tested;

[0027] Preferably, the second cavity and the flue gas pipeline to be tested are both aligned and connected to the center of the charged region;

[0028] Preferably, the charged region is connected to a smoke outlet pipe, and the smoke outlet pipe has the same diameter as the flue gas pipe to be tested.

[0029] Preferably, the first compensation control amount is obtained by the following formula:

[0030] OUT1=Kp*Ek+Ki*SEk+Kd*(Ek-Ek_1);

[0031] The second compensation control quantity is obtained by the following formula:

[0032] OUT2=K_p*(P-P0)+K_t*(T-T0)SEk+K_h*(H-H0);

[0033] Where Ek is the error between the current value and the target value; Ek_1 is the error between the previous current value and the target value; SEk is the accumulated error; Kp is the proportional coefficient, Ki is the integral coefficient, and Kd is the differential coefficient;

[0034] T0=25℃, P0=101.325kPa,, H0=50%RH;

[0035] K_p, K_t, K_h are the compensation coefficients obtained from the fitting.

[0036] Preferably, the total compensation control quantity OUT = OUT1 + OUT2.

[0037] A second aspect of this application provides a corona discharge stability control method for aerosol concentration detection, applied to the apparatus described in the first aspect of this application, comprising the following steps:

[0038] Collect the discharge current of the corona needle, the temperature, humidity and air pressure of the device;

[0039] A compensation algorithm is used to compensate and control the discharge current of the corona needle to obtain a first compensation control quantity, and to compensate and control the temperature, humidity and air pressure to obtain a second compensation control quantity. The first compensation control quantity and the second supplementary control quantity are combined to obtain a total compensation control quantity, and the duty cycle of the PWM signal of the control chip is adjusted through the total compensation control quantity.

[0040] A third aspect of the present application provides an electronic device for measuring the concentration and / or average particle size of a test flue gas based on the charged diffusion method, comprising a charged module including the device described in the first aspect of the present application, as well as a separation module and a sensor module;

[0041] The charging module receives clean air and flue gas to be tested respectively. The clean air is ionized by the corona needle connected to the DC positive high voltage pulse, generating a large number of positive ions. In the charged region, the positive ions attach to the particulate matter to be tested in the flue gas to form charged particulate matter.

[0042] The charged particles enter the separation module, where they are subjected to the combined effects of the separation electric field and the flow field, causing charged particles of different sizes to have different flight paths, thereby achieving sieving.

[0043] Charged particles exceeding the threshold particle size enter the particle collection device in the sensor module. The particle collection device measures the charge carried by the charged particles, then detects the generated micro-current value through the operational amplifier circuit, and finally inverts to obtain the concentration and particle size of the particles.

[0044] A third aspect of this application provides a computer-readable storage medium for storing a computer program that, when run on a computer, causes the computer to perform the method described in the second aspect of this application.

[0045] Beneficial effects

[0046] The technical solution provided in this application provides a ring electrode in terms of structural design, which makes the discharge area extend linearly, ensures that the airflow passes through the entire discharge area uniformly, avoids turbulence, eddies or low-speed dead zones, and finds a fine balance between high electric field strength and avoiding breakdown, which helps to reduce discharge voltage and current.

[0047] This embodiment also controls the discharge current to the nA level and the discharge voltage to around 2kV through electrical design, reducing the risk of high voltage and high current generation.

[0048] This embodiment optimizes the control strategy, taking into account the impact of environmental changes and dynamically adjusting the control based on changes in discharge characteristics, in order to achieve stable discharge. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the structure of an aerosol concentration detection device according to an embodiment of this application;

[0050] Figure 2 This application Figure 1 A schematic diagram of the core structure of the charged module in the embodiment;

[0051] Figure 3 This is a schematic diagram of the structure of the corona needle in an embodiment of this application;

[0052] Figure 4 This is a schematic diagram of the composition of the electronic control module in an embodiment of this application;

[0053] Figure 5 This is a circuit diagram of the power supply component, half-bridge drive module, LC resonant module and transformer module in the circuit module of this application embodiment;

[0054] Figure 6 This is a circuit diagram of the voltage doubler rectifier module in the circuit module of this application embodiment;

[0055] Figure 7 This is a circuit diagram of the feedback module in the circuit module of an embodiment of this application;

[0056] Figure 8 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application.

[0057] 1. First cavity; 2. Second cavity; 3. Charged area; 4. Clean air pipeline; 5. Test gas pipeline; 6. Exhaust gas pipeline; 7. Corona needle; 7-1. Needle holder; 7-2. Needle body; 7-3. Ball screw; 8. Circuit board; 9. First connection structure; 10. Second connection structure. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application will be described in further detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely for explaining this application and not for limiting it. It should also be noted that, for ease of description, only the parts relevant to this application are shown in the drawings, not all of them. Before discussing exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but may also have additional steps not included in the drawings. The process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0059] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0060] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0061] The following description, in conjunction with the accompanying drawings, details the electronic device for aerosol detection, the corona discharge stability control device within the electronic device, the control method, and the related media provided in this application, through specific embodiments and application scenarios.

[0062] Example 1

[0063] Figure 1 This is a schematic diagram of the composition of an electronic device for aerosol detection provided in Embodiment 1 of this application, as shown below. Figure 1 As shown, the electronic device includes:

[0064] The device comprises a charging module, an ion separation module, and a sensor module. Based on the diffusion-charging (DC) method, it measures the number concentration and / or average particle size of aerosols (especially nano- and submicron-sized particles) in real time and online. The core idea of ​​this method is to impart a known, controllable charge to aerosol particles, then measure the current generated by these charged particles to calculate the particle concentration and / or size.

[0065] After clean air and the flue gas to be tested enter the charging module, the clean air is ionized by the corona needle 7 connected to a DC positive high voltage pulse, generating a large number of positive ions. In the charging region, the positive ions attach to the particulate matter to be tested in the gas. Then, the charged particles enter the ion separation module. A separation voltage is applied to the electrode at the center of the ion separation module. The charged particles are affected by the electric field and the flow field, so that charged particles of different sizes have different flight paths, thereby achieving the effect of screening particles of different sizes. Then, large particles exceeding the threshold can enter the particle collection device in the subsequent sensor module with charge. The particle collection device measures the charge of the charged particles, and then detects the generated micro-current value through the operational amplifier circuit. Finally, the concentration and / or particle size of the particles are obtained by inversion.

[0066] Figure 2 The diagram shows the core structure of the charged module, namely the corona discharge stability device used for aerosol concentration detection. This core structure is assembled with a housing to form the complete module. Figure 1 The charging module in the electronic device shown.

[0067] The corona discharge stability device for aerosol concentration detection includes the following main components:

[0068] The ring electrode and the corona needle 7 are provided. The ring electrode includes a narrow first cavity 1 and a second cavity 2 that is shorter and wider than the first cavity 1 arranged coaxially. The corona needle 7 is coaxially located in the first cavity 1 and the tip of the corona needle 7 is located in the first cavity 1 near the second cavity 2. The gap between the corona needle 7 and the first cavity 1 is 1.8mm to 2.5mm. A first entrance is provided in the first cavity 1 away from the second cavity 2. The distance between the first entrance and the needle tip is greater than 5 times the inner diameter of the first cavity 1.

[0069] The clean air duct 4 is connected to the first inlet and is used to introduce clean air into the first cavity 1.

[0070] A charged region 3 is disposed on the other side of the second cavity 2, connected to the first cavity 1, and the volume of the charged region 3 is larger than that of the second cavity 2. The charged region 3 is connected to the flue gas duct 5 to be tested. The charged region 3 is also connected to the flue gas outlet duct 6.

[0071] The flue gas pipeline 5 to be tested is arranged on the other side of the charged region 3, relative to the second cavity 2.

[0072] The circuit module uses a control chip to control the low-voltage DC power signal through a half-bridge drive, LC resonance, transformer, and voltage doubler rectification to convert it into a high voltage of 2kV±5% and apply it between the corona needle 7 and the ring electrode. It also collects the discharge current of the corona needle 7, the temperature, humidity and air pressure of the device.

[0073] The control module is used to obtain a first compensation control quantity by performing compensation control on the discharge current of the corona needle 7 using a compensation algorithm, and to obtain a second compensation control quantity by performing compensation control on temperature, humidity and air pressure. The first compensation control quantity and the second supplementary control quantity are combined to obtain a total compensation control quantity, and the duty cycle of the PWM signal of the control chip is adjusted through the total control quantity.

[0074] like Figure 2As shown, the corona discharge stability device for aerosol concentration detection is a base. The clean air pipeline 4, the flue gas pipeline 5, and the exhaust pipeline 6 are all located inside the base, and corresponding connectors are provided at the openings of each pipeline for connection with other related pipelines outside the base. A ring electrode mounting channel is also provided inside the base to accommodate the ring electrode, allowing for its disassembly and assembly. The ring electrode mounting channel is connected to the clean air pipeline 4. The ring electrode has a columnar structure, inside which a needle seat mounting channel, a first cavity 1, and a second cavity 2 are sequentially connected. A through-hole is provided on the side wall of the first cavity 1 near the needle seat mounting channel. When the ring electrode is assembled into the ring electrode mounting channel, the through-hole aligns with the clean air pipeline 4, allowing gas from the clean air pipeline 4 to enter the first cavity 1 through the through-hole.

[0075] like Figure 3 The diagram shows the structure of the corona needle 7, including a needle body 7-2, a needle seat 7-1, and a ball screw 7-3. The needle seat 7-1 is a threaded cylinder with an end portion having a diameter larger than the cylinder. The needle seat 7-1 is installed by engaging with the end portion of the first through hole of the annular electrode away from the second through hole through the threaded area, and the end portion of the needle seat 7-1 abuts against the base. The needle seat 7-1 has an internal through hole that axially penetrates the needle seat cylinder and the end portion. One side of the through hole has a smaller diameter for fixing the end portion of the needle body 7-2, while the other side has a larger diameter and is a threaded hole for fixing the ball screw 7-3, thus forming an electrical connection between the ball screw 7-3 and the end portion of the needle body 7-2. In this embodiment, the diameter D of the needle body 7-2 is 0.4mm~0.6mm, the radius of curvature of the needle tip is 5μm, the external thread of the needle seat 7-1 is an M5 thread, the distance L1 from the end of the needle seat 7-1 to the needle tip is 42.5mm, and the length L2 of the needle body 7-2 exposed outside the needle seat 7-1 is 26.5mm. Accordingly, after the corona needle 7 is assembled into the annular electrode, the distance from the end face of the needle seat 7-1 near the second cavity to the second cavity is 26.6mm, so that the end of the corona needle 7 is basically located at the junction of the first cavity and the second cavity.

[0076] In the above structure, the annular electrode is grounded, and the corona needle 7 is located in the first cavity 1, forming a coaxial needle-ring electrode structure. The needle tip is located at the center of the annular electrode, ensuring axial symmetry of the electric field distribution. The short distance between the corona needle 7 and the annular electrode can effectively reduce the discharge voltage to about 2KV, which is 43-60% lower than the voltage of the existing needle-plate structure (5-8mm spacing). The electric field strength on the tip surface of the corona needle 7 reaches 32kV / cm, which meets the air ionization threshold of 30kV / cm. The electric field is concentrated in the tip region, avoiding spark breakdown caused by electric field diffusion, improving the electrode's corrosion resistance, and helping to protect the corona needle 7 and maintain its service life. After clean air enters the annular electrode, the distance from the needle tip is more than 5 times the inner diameter of the tube. In this embodiment, the diameter of the first cavity 1 is 4.2mm. At this time, the Reynolds number of the airflow reaches the laminar flow critical value Re=1800 or more, and the airflow is in a stable laminar flow state without turbulence, which helps the airflow enter the discharge zone in a laminar manner and reduces disturbance.

[0077] The needle tip is located adjacent to the first cavity 1 and the second cavity 2 of the annular electrode, combined with Figure 2 As shown, the ring electrode forms a funnel-shaped discharge region at its left end, allowing ions generated by the needle tip discharge to rapidly flow into the larger second cavity 2 and further diffuse into the charged region 3, thus improving the utilization rate of discharged ions and reducing ion loss. In this embodiment, the second cavity 2 has a diameter of 9 mm, an axial length of 8.2 mm, and a volume of approximately 521 mm². 3 The compact structure of the second cavity 2 ensures concentrated ion concentration and increases the probability of collision with particulate matter.

[0078] In this embodiment, the charged region 3 is cylindrical, and the space of the charged region 3 is 2-5 times that of the second cavity 2. In some preferred embodiments, the diameter of the charged region 3 is larger than the diameter of the second cavity 2 and the flue gas pipeline 4 to be tested. For example, if the diameter of the charged region 3 is 14.5 mm, the length is 13.4 mm, and the volume is approximately 2212 mm². 3 The volume of the charging region is approximately 3-4 times that of the discharge region. The charging region 3 is larger than the discharge region and is seamlessly connected to the discharge region, which avoids the generation of eddies in the airflow at the junction of the two regions. This ensures that the residence time of ions and particles in the charging region 3 is extended. The longer charging time allows ions and particles to fully combine, improving the charging efficiency from about 75% in the existing technology to 92%, without overcharging.

[0079] In some preferred embodiments, the corona needle 7 is made of a tungsten-lanthanum alloy composed of a tungsten matrix doped with 1.2% to 1.8% lanthanum oxide, for example, the lanthanum oxide content in the tungsten-lanthanum alloy is 1.5%. This alloy has the characteristics of high temperature strength, high recrystallization temperature, and excellent creep performance. After 5000 hours of ion bombardment, the needle tip etching depth is <5μm, which can ensure electric field stability. Therefore, using it as the material for the corona needle 7 can effectively improve the service life of the corona needle 7.

[0080] In some preferred embodiments, the ring electrode is made of stainless steel. For example, 316 stainless steel is selected because it has strong corrosion resistance, avoiding electrode oxidation during long-term use that could lead to decreased conductivity and affect the electric field. Furthermore, 316 stainless steel has low resistivity and excellent conductivity, ensuring reliable grounding and reducing electric field interference.

[0081] The structure and material of the corona needle 7 and the ring electrode in the above embodiments enable the discharge voltage to be reduced to about 2kV while meeting the air ionization threshold of ≥30kV / cm at the needle tip field strength, thus avoiding spark breakdown caused by electric field diffusion.

[0082] In some preferred embodiments, to avoid turbulence before and after the clean air enters the first cavity 1, the diameter of the clean air pipe 4 is the same as the diameter of the first cavity 1. Preferably, the inner wall of the clean air pipe 4 is polished to achieve a roughness Ra < 0.8 μm, which can reduce airflow resistance and further ensure laminar flow.

[0083] In some preferred embodiments, both the second cavity 2 and the flue gas pipeline 5 are perpendicular to the axis of the charged region 3. In some preferred embodiments, both the second cavity 2 and the flue gas pipeline 5 are aligned and connected to the center of the charged region 3. Charged particles from the second cavity 2 collide head-on with the flue gas in the flue gas pipeline 5 in the charged region 3, causing the flue gas to become charged and leave the charged region 3 through the exhaust pipe 6.

[0084] In some preferred embodiments, the smoke outlet pipe 6 has the same diameter as the flue gas pipe 5 to be tested.

[0085] like Figure 2 As shown, the circuit module is mounted on a circuit board 8, and the circuit board 8 is fixed to the side of the base. Figure 2 In this configuration, the circuit board 8 is fixed to the base via a first connecting structure 9, which mainly includes a connecting seat and bolts. One end of the connecting seat is threaded to the side of the base, and the circuit board 8 is fixed to the threaded hole at the other end of the connecting seat by bolts. Simultaneously, the circuit board 8 is electrically connected to the corona needle 7 via a second connecting structure 10, which includes the ball screw 7-3 and a matching nut.

[0086] The above-mentioned circuit modules and control modules are collectively referred to as electronic control modules, such as... Figure 4 This is a schematic diagram of the electronic control module composition of this application, by Figure 4 It can be seen that it includes the following components:

[0087] Input power supply, the standard power supply provided by the device. This includes a +14.5V DC main power supply, providing energy for high-voltage conversion; a +5V DC logic power supply, powering the driver chip; a +3.3V DC MCU power supply, powering the control chip; and a -6V DC auxiliary power supply, providing negative power to the operational amplifier.

[0088] The core control chip, MCU, is an STM32F407 with a main frequency of 168MHz selected in this embodiment. It is responsible for outputting PWM control signals, collecting feedback data, and executing algorithm logic.

[0089] The core function of the circuit module is low-voltage DC to high-voltage DC conversion and nA-level current closed-loop control. Specifically, it achieves low-voltage DC to high-voltage DC conversion by setting up a half-bridge drive module, an LC resonant module, a transformer module, and a voltage multiplier rectifier module connected in sequence. Simultaneously, it collects the discharge current in real time and adjusts the output through feedback to ensure the current is stable at a target value of approximately 200nA, for example, controlling current fluctuations to <0.5nA to meet micro-current detection requirements. Compared to traditional high-voltage discharge scenarios that use transformers to achieve high-voltage output, the circuit in this embodiment utilizes a combination of a high-frequency transformer and a diode capacitor voltage multiplier circuit. The circuit is relatively lightweight and well-suited for high-voltage, low-current scenarios.

[0090] The signal flow of the above-mentioned electronic control module is as follows: MCU outputs PWM signal → half-bridge drive circuit → LC resonant circuit and transformer generate high-frequency pulse voltage → 8-fold voltage multiplier rectifier circuit boosts to 2kV DC → corona needle 7 discharges → feedback loop collects discharge current → MCU adjusts PWM duty cycle according to current deviation to form closed-loop control.

[0091] The specific composition of each part in the above circuit module belongs to the prior art. The embodiments of the present invention provide, as follows: Figures 5 to 7 The specific structure, model, parameters, etc. shown are for reference. Below, we will introduce some of its important components.

[0092] Half-bridge driver module

[0093] Its function is to convert the low-power PWM signal output by the MCU into a high-power drive signal that can drive the MOSFET, ensuring that the MOSFET is turned on in a time-sharing manner according to the control logic and avoiding short circuits.

[0094] Core component selection:

[0095] Driver chip U2, model UCC27211DR, is a high-voltage half-bridge gate driver. It receives the PWM low-voltage logic signal from the MCU and converts it into drive signals that can quickly and forcefully turn on and off the two power switching transistors (MOSFETs) on the high-voltage and low-voltage sides. This driver has a switching speed of 100V / ns, an output current of ±4A, and can quickly drive MOSFETs while reducing switching losses.

[0096] MOSFETs U4 and U5, model FDD86540, are N-channel enhancement-type MOSFETs with a drain-source voltage of 600V and an on-resistance of 0.028Ω. As the core power transistors for the half-bridge driver, they provide sufficient drive capability to ensure stable oscillation of the subsequent LC resonant circuit.

[0097] Zener diodes D10, D11, and D12: Model SM6T33CA, are 33V transient voltage suppressor diodes used to absorb transient high voltages in the circuit and protect the driver chip and MOSFET.

[0098] The working principle of the half-bridge drive module: The MCU outputs two complementary PWM signals (PWM_HI: high-side control, PWM_LI: low-side control), which are amplified by U2 (UCC27211DR) and converted into PWM_HO (high-side drive) and PWM_LO (low-side drive) signals; PWM_HO drives U5 (high-side MOSFET), and PWM_LO drives U4 (low-side MOSFET), and the two signals have a "dead time" (1μs) to avoid U4 and U5 being turned on at the same time and causing a short circuit in the power supply; when U4 and U5 are turned on in a time-sharing manner, they charge and discharge the LC resonant circuit to generate a high-frequency pulse voltage.

[0099] LC resonant circuit

[0100] It enables the conversion of DC voltage to alternating current, providing the conditions for transformer voltage boosting.

[0101] Core component selection:

[0102] Inductance L: The primary coil of the transformer is used as the inductance, with an inductance value of 43μH.

[0103] Capacitor C: Metallized polypropylene film capacitor CL21X106K500V, capacitance 10μF±10%, withstand voltage 500V, loss tangent <0.01, excellent high-frequency characteristics. Through precise capacitance matching, it works in conjunction with the primary inductance of the transformer to generate a high-frequency pulse voltage at a set frequency.

[0104] According to the formula for the resonant frequency of an LC series circuit: =7.68 KHz.

[0105] Operating mode selection: The circuit switching frequency (determined by the MCU's PWM signal) is set to 16KHz to satisfy "switching frequency fs>resonant frequency fr". At this time, the circuit operates in continuous current mode (CCM). The inductor current is always greater than 0 throughout the entire switching cycle, and the current ripple is <5nA, ensuring the stable output voltage of the subsequent voltage doubler rectifier circuit.

[0106] Transformer module

[0107] Core component selection: FL2015-2L(U9), with a turns ratio of 1:67, realizes primary voltage boost function, and the maximum voltage can be boosted to about 970V.

[0108] Voltage multiplier module

[0109] The function of the voltage multiplier module is to boost the approximately 250V high-frequency pulse voltage generated by the LC resonant module and the transformer module to 2kV DC through capacitor charging and discharging, thus achieving 8 times the voltage and providing a stable high-voltage power supply for the corona needle 7.

[0110] Core component selection:

[0111] Rectifier diodes D2, D5, D7, D8, D9, D11, D12, and D13: Model BYG23M-E3 / IR, are ultra-fast recovery diodes with high-efficiency rectification characteristics, ensuring voltage conversion efficiency during the voltage multiplication process. Specific parameters are: withstand voltage of 1000V, forward current of 1A, and reverse recovery time of <50ns, reducing high-frequency rectification losses.

[0112] Voltage multiplier capacitors C10, C11, C12, C13, C14, C15, C16, and C17: These are 10nF / 1000V ceramic capacitors with a high voltage rating of 1000V, excellent high-frequency characteristics, and non-polarity, making them suitable for voltage multiplier circuits.

[0113] Working principle: Using the input high-frequency pulse voltage Vin, the circuit achieves an ideal output voltage Vout≈8×Vin through the charging and discharging superposition of 8-stage diode-capacitor units. In practical applications, due to component losses, the output voltage is approximately 2kV, and Vin≈250V, meeting the corona discharge requirements. Compared to traditional transformer boosting solutions, this circuit reduces volume by 40% and weight by 50%, making it more suitable for portable aerosol detection equipment.

[0114] Feedback module

[0115] The function of the feedback module is to collect the discharge current of the corona needle 7 in real time. This module is responsible for collecting the discharge current signal of the corona needle 7, converting it into a voltage signal that the MCU can collect, and transmitting it to the MCU for processing. It provides current feedback data for closed-loop control. The core component is a signal acquisition and conversion element. The core requirements are low noise and high precision. The high precision requires a current detection accuracy of ±0.5nA.

[0116] Core component selection:

[0117] Operational amplifiers U3A and U3C: Model LMC660AIMX / NOPB, are low-noise precision operational amplifiers used to amplify weak discharge current sampling signals and improve signal recognition. They have an input bias current of <1pA, an input offset voltage of <10μV, and a noise voltage of <5nV / √Hz at 1kHz. They have low noise characteristics and are suitable for micro-current detection.

[0118] The sampling resistor R18 has parameters of 100KΩ±1% and R19 has parameters of 30kΩ±1%. The discharge current and discharge voltage are collected by the voltage drop generated by the current flowing through the resistor. The temperature coefficient is ±50ppm / ℃ to ensure the accuracy of current-to-voltage conversion.

[0119] Filter capacitors C1, C2, C5, and C8: 1000pF ceramic capacitors are selected to filter out high-frequency noise and ensure stable feedback voltage.

[0120] Based on the operational amplifier's "virtual short" (voltages at the non-inverting and inverting inputs are equal) and "virtual open" (input current is 0) characteristics, the derivation process for current sensing is as follows:

[0121] The discharge current I flows through the sampling resistor R18, generating a voltage drop across R18: (Because the current flows from the ring electrode to the corona needle 7, the upper end of R18 in the figure is negative and the lower end is positive.)

[0122] Operational amplifier U3A forms an inverting proportional amplifier circuit. The non-inverting input is grounded (voltage 0V). According to the "virtual short", the voltage at the inverting input is ≈0V.

[0123] The voltage divider circuit (R10=10KΩ, R12=66KΩ) collects the voltage at the output terminal of the operational amplifier, and obtains: (AI2 is the voltage corresponding to the ADC sample value of the MCU);

[0124] The operational amplifier U3C forms a secondary voltage divider circuit to obtain the voltage at the FB0 terminal (MCU ADC input terminal): (R11=22KΩ);

[0125] After simplification, the final discharge current calculation formula is: I = 3000 × AI² - 4500nA, with a calculation accuracy of ±0.5nA, which meets the requirements for nA-level current detection.

[0126] By designing the high-precision circuit described above, precise control of the 200nA discharge current is achieved, with current fluctuation <0.5nA, meeting the requirements for micro-current detection.

[0127] In some preferred embodiments, the control module employs a strategy of PID closed-loop control plus environmental parameter compensation. The PID closed-loop control handles rapid dynamic disturbances such as current drift caused by needle tip etching, which cause changes in the characteristics of the corona needle 7. The environmental compensation handles slow static disturbances such as changes in temperature, air pressure, and humidity. The combination of the two achieves stable current control in all scenarios, resulting in a relative standard deviation (RSD) of the discharge current of less than 1%, thereby improving the environmental applicability range.

[0128] Specifically, the first compensation control quantity is dynamically compensated through PID control. Its function is to calculate the corresponding control quantity based on the deviation between the current current and the target current, adjust the PWM duty cycle, and make the current approach the target value. The control logic framework is as follows:

[0129] Step 1: Set the target current Is (e.g., 200nA);

[0130] Step 2: Collect the current discharge current Ig (through the feedback loop);

[0131] Step 3: Calculate the current deviation Ek = Is - Ig;

[0132] Step 4: Calculate the control quantity OUT_fb using the PID algorithm;

[0133] Step 5: Adjust the duty cycle of the PWM signal according to OUT_fb to change the output high voltage, and then adjust Ig;

[0134] Step 6: Repeat steps 2-5 to form a closed-loop control.

[0135] The above process ultimately yields the output using the following formula:

[0136] OUT1=Kp*Ek+Ki*SEk+Kd*(Ek-Ek_1);

[0137] Where Ek is the error between the current value and the target value;

[0138] Ek_1 is the error between the current value and the target value in the previous step, which is used to calculate the rate of change of the deviation;

[0139] SEk is the accumulated error, that is, the accumulated value of Ek over a period of time, which is used to eliminate steady-state error;

[0140] Kp is the proportionality coefficient, which reflects the degree of influence of the current deviation. The larger Kp is, the faster the response, but the more prone to overshoot.

[0141] Ki is the integral coefficient, which reflects the degree of influence of the cumulative deviation. The larger Ki is, the smaller the steady-state error, but the more prone it is to oscillation.

[0142] Kd is the differential coefficient, which reflects the degree of influence of the deviation rate of change. The larger Kd is, the stronger the anti-interference ability, but the easier it is to introduce noise.

[0143] Specifically, Kp, Ki, and Kd are determined using the Ziegler-Nichols tuning method. In this embodiment, the tuning process specifically includes:

[0144] Initialization: Set Ki=0 and Kd=0, gradually increase Kp until the current exhibits constant amplitude oscillation, and record the critical proportional coefficient Kcr=2.5 and the oscillation period Tcr=0.1s at this time;

[0145] Calculation parameters: According to the Ziegler-Nichols tuning formula, Kp=0.6×Kcr=1.5, Ki=2×Kp / Tcr=30, Kd=Kp×Tcr / 8=0.01875;

[0146] Verification results: Experimental results show that under these parameters, the current response time is <0.5s, the overshoot is <5%, and the steady-state error is <0.5nA, which meets the requirements of dynamic control.

[0147] On the other hand, environmental parameters (temperature T, air pressure P, humidity H) affect the equivalent impedance of corona discharge by changing air density and composition, leading to current drift under the same voltage. Therefore, the second compensation control variable quantifies the influence of environmental parameters on the current and adjusts the control variable in advance to achieve static environmental compensation, which counteracts environmental interference.

[0148] The mechanism by which air pressure P affects corona discharge is as follows: reduced air pressure → reduced air density → increased mean free path of gas molecules → electrons can easily gain energy → reduced difficulty of ionization → increased current.

[0149] The mechanism by which temperature T affects corona discharge is as follows: as temperature increases, air density decreases (at the same air pressure), making ionization easier and increasing current. At the same time, as temperature increases, molecular thermal motion intensifies, leading to changes in ion mobility. Overall, they are positively correlated.

[0150] The mechanism by which humidity (H) affects corona discharge is as follows: increased humidity → more water molecules (polar molecules) → electrons are adsorbed by water molecules → decreased ion mobility → increased difficulty of ionization → decreased current.

[0151] The process of achieving the above-mentioned environmental compensation is as follows:

[0152] Step 1: Data Acquisition Phase

[0153] In a controlled environment chamber (constant temperature, humidity, and pressure chamber, model THP-150), data was collected using the "single-variable control method," including:

[0154] With a fixed temperature T=25℃ and air pressure P=101.325kPa, the humidity H=20%RH~80%RH (in 10%RH increments) was adjusted, and the voltage V required to maintain Ig=200nA under each set of H was recorded.

[0155] With a fixed temperature T=25℃ and humidity H=50%RH, adjust the air pressure P=80kPa~120kPa (in 5kPa increments) and record the corresponding V values;

[0156] With fixed air pressure P=101.325kPa and humidity H=50%RH, the temperature was adjusted to -10℃~50℃ (in 5℃ increments), and the corresponding V values ​​were recorded. Finally, 50 sets of valid data were collected to form an "environmental parameters-compensation voltage" dataset.

[0157] Step 2: Model Fitting Stage

[0158] The collected data were fitted using "multiple linear regression analysis" (least squares method) to construct an environmental compensation model. The second compensation control variable was obtained using the following formula:

[0159] OUT2=K_p*(P-P0)+K_t*(T-T0)SEk+K_h*(H-H0);

[0160] Among them, T0=25℃, P0=101.325kPa, and H0=50%RH constitute the standard environmental parameters;

[0161] K_p, K_t, K_h are the compensation coefficients obtained from the fitting.

[0162] In this embodiment, the following values ​​were obtained through data fitting: Kp = -0.02V / kPa; Kt = 0.015V / ℃; Kh = 0.03V / %RH.

[0163] Step 3: Model goodness verification:

[0164] The coefficient of determination R² of the fitted model is 0.985, indicating that the model can explain 98.5% of the voltage change, and the current drift caused by environmental changes after compensation is <1nA.

[0165] Furthermore, in this embodiment, during real-time compensation, the MCU collects T, P, and H data in real time through environmental sensors (barometric pressure sensor BMP280, accuracy ±0.12hPa; temperature and humidity sensor SHT30, accuracy ±0.3℃ / ±2%RH), substitutes them into the compensation formula to calculate OUT2, and superimposes it with the PID control quantity OUT1 to obtain the total compensation control quantity OUT=OUT1+OUT2. Then, the PWM duty cycle is adjusted according to OUT to achieve real-time cancellation of environmental interference.

[0166] The aforementioned device addresses multiple aspects, including structure, circuitry, and control, to achieve precise control of the discharge current. Specifically, through electrode structure optimization, the discharge voltage is controlled at 2kV±5% to prevent spark breakdown. Etch-resistant electrode materials are selected to extend the lifespan of the corona needle 7 to over 5000 hours. By designing an nA-level current control circuit and combining dynamic and static compensation algorithms, the discharge current is stabilized at the target value (e.g., 200nA), with a relative standard deviation (RSD) of <1%. Furthermore, by optimizing the airflow path design, the airflow enters the discharge zone in a laminar flow manner, extending the particulate matter charging time and increasing the charging efficiency to ≥92%. The device in the above embodiment exhibits good environmental adaptability, operating stably within a range of -10~50℃ (temperature), 80~120kPa (pressure), and 20~80%RH (humidity) without requiring manual calibration.

[0167] This application also provides a corona discharge stability control method for aerosol concentration detection, applied to the device described in the above embodiments. In the process of detecting aerosol concentration using the charge method, the method is as follows:

[0168] Step S102: Collect the discharge current of the corona needle 7, the temperature, humidity and air pressure of the device.

[0169] Step S103: Use a PID control algorithm to compensate the discharge current of the corona needle 7 to obtain a first compensation control quantity and to compensate the temperature, humidity and air pressure to obtain a second compensation control quantity. Combine the first compensation control quantity and the second compensation control quantity to obtain a total compensation control quantity, and adjust the duty cycle of the PWM signal of the control chip through the total compensation control quantity.

[0170] The specific control parameters involved in this embodiment are consistent with those in the previous implementation. Based on this, the above method specifically includes the following process:

[0171] Step S1: Initialization Phase

[0172] Set the target current Is = 200nA;

[0173] The standard environmental parameters were set as follows: P0 = 101.325 kPa, T0 = 25℃, and H0 = 50% RH.

[0174] Load the PID parameters Kp=1.5, Ki=30, Kd=0.01875;

[0175] Environmental compensation coefficients: Kp = -0.02V / kPa, Kt = 0.015V / ℃, Kh = 0.03V / %RH;

[0176] Initialize the cache variables: Ek-1=0, SEk=0, and the initial value of the PWM duty cycle is 50%.

[0177] Step S2, Data Acquisition Phase

[0178] The discharge current Ig is sampled every 10ms (sampled by the ADC at the FB0 terminal of the feedback loop).

[0179] Environmental parameters are collected every 500ms: temperature T (SHT30), air pressure P (BMP280), and humidity H (SHT30).

[0180] Step S3: Environmental Compensation Calculation Stage

[0181] Substituting into the environmental compensation formula, we calculate OUT2 = Kp × (P - P0) + Kt × (T - T0) + Kh × (H - H0).

[0182] Step S4, PID Calculation Stage

[0183] Calculate the current error Ek = Is - Ig;

[0184] Calculate the cumulative error SEk = SEk + Ek (set to 10 if SEk > 10, and set to -10 if SEk < -10 to avoid integral saturation).

[0185] Calculate the error change rate ΔEk = Ek - Ek-1;

[0186] Calculate the PID control quantity OUT1 = Kp × Ek + Ki × SEk + Kd × ΔEk.

[0187] Step S5, Control Output Stage

[0188] Calculate the total control quantity OUT = OUT1 + OUT2;

[0189] Adjust the PWM duty cycle according to OUT: for every 0.1V increase in OUT, the PWM duty cycle increases by 0.1%; for every 0.1V decrease in OUT, the PWM duty cycle decreases by 0.1% (the PWM duty cycle is limited to between 5% and 95% to avoid extreme values ​​that could cause circuit failure).

[0190] The adjusted PWM signal is output to the half-bridge drive circuit.

[0191] Step S6, Iterative Update Phase

[0192] Update the error cache: Ek-1 = Ek;

[0193] Return to step S2 and enter the next control cycle, repeating the process.

[0194] like Figure 8 As shown, this application embodiment also provides an electronic device 700, including a processor 701, a memory 702, and a program or instructions stored in the memory 702 and executable on the processor 701. When the program or instructions are executed by the processor 701, they implement the various processes of the above-described embodiment of a corona discharge stability control method for aerosol concentration detection and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0195] It should be noted that the electronic devices in the embodiments of this application include mobile electronic devices and non-mobile electronic devices.

[0196] This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described embodiment of a corona discharge stability control method for aerosol concentration detection, and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0197] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0198] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above embodiment of the corona discharge stability control method for aerosol concentration detection, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0199] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0200] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0201] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0202] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0203] The above description is merely a preferred embodiment and the technical principles employed in this application. This application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions that can be made by those skilled in the art will not depart from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of this application. The scope of this application is determined by the scope of the claims.

Claims

1. A corona discharge stability device for aerosol concentration detection, characterized in that, include: The device comprises a ring electrode and a corona needle. The ring electrode includes a narrow, elongated first cavity arranged coaxially and a second cavity that is shorter and wider than the first cavity. The corona needle is coaxially located in the first cavity, with its tip positioned near the second cavity. A first inlet is provided in the first cavity away from the second cavity, and the distance between the first inlet and the needle tip is greater than five times the inner diameter of the first cavity. The diameter of the corona needle is 0.4 mm to 0.6 mm, and the radius of curvature of the needle tip is 5 μm. A clean air duct, connected to the first inlet, is used to introduce clean air into the first cavity; the diameter of the clean air duct is the same as the diameter of the first cavity. A charged region is arranged on the other side of the second cavity, relative to the first cavity, and the volume of the charged region is larger than that of the second cavity, the space of the charged region being 2-5 times that of the second cavity; the charged region is connected to a smoke outlet pipe; The flue gas pipeline to be tested is arranged on the other side of the charged region, relative to the second cavity; The circuit module uses a control chip to control the low-voltage DC power signal through a half-bridge drive, LC resonance, transformer, and voltage doubler rectifier to convert it into a high voltage of 2kV±5% and apply it between the corona needle and the ring electrode. It also collects the discharge current of the corona needle, the temperature, humidity and air pressure of the device. The control module is used to use a compensation algorithm to compensate the discharge current of the corona needle to obtain a first compensation control quantity and to compensate the temperature, humidity and air pressure to obtain a second compensation control quantity. The first compensation control quantity and the second supplementary control quantity are combined to obtain a total compensation control quantity. The duty cycle of the PWM signal of the control chip is adjusted through the total compensation control quantity so that the discharge current of the corona needle is stabilized at 200nA±5nA. The first compensation control value is obtained by the following formula: OUT1=Kp*Ek+Ki*SEk+Kd*(Ek-Ek_1); The second compensation control quantity is obtained by the following formula: OUT2=K_p*(P-P0)+K_t*(T-T0)SEk+K_h*(H-H0); Where Ek is the error between the current value and the target value; Ek_1 is the error between the previous current value and the target value; SEk is the accumulated error; Kp is the proportional coefficient, Ki is the integral coefficient, and Kd is the differential coefficient; T0=25℃, P0=101.325kPa, H0=50%RH; K_p, K_t, K_h are the compensation coefficients obtained from the fitting.

2. The apparatus according to claim 1, characterized in that, The charged region is cylindrical, and the second cavity and the flue gas pipeline under test are both perpendicular to the axis of the charged region.

3. The apparatus according to claim 1, characterized in that, The total compensation control quantity OUT = OUT1 + OUT2.

4. A method for controlling the stability of corona discharge for aerosol concentration detection, using the apparatus described in any one of claims 1-3, characterized in that, Collect the discharge current of the corona needle, the temperature, humidity and air pressure of the device; A compensation algorithm is used to compensate and control the discharge current of the corona needle to obtain a first compensation control quantity, and to compensate and control the temperature, humidity and air pressure to obtain a second compensation control quantity. The first compensation control quantity and the second supplementary control quantity are combined to obtain a total compensation control quantity, and the duty cycle of the PWM signal of the control chip is adjusted through the total compensation control quantity.

5. An electronic device for measuring the concentration and / or average particle size of a test flue gas based on the charged diffusion method, characterized in that, Includes a charging module comprising any one of the devices described in claims 1-3, as well as a separation module and a sensor module; The charging module receives clean air and flue gas to be tested respectively. The clean air is ionized by the corona needle connected to the DC positive high voltage pulse, generating a large number of positive ions. In the charged region, the positive ions attach to the particulate matter to be tested in the flue gas to form charged particulate matter. The charged particles enter the separation module, where they are subjected to the combined effects of the separation electric field and the flow field, causing charged particles of different sizes to have different flight paths, thereby achieving sieving. Charged particles exceeding the threshold particle size enter the particle collection device in the sensor module. The particle collection device measures the charge carried by the charged particles, then detects the generated micro-current value through the operational amplifier circuit, and finally inverts to obtain the concentration and particle size of the particles.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program that, when run on a computer, causes the computer to perform the method as described in claim 4.

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