Negative ion collector, negative ion concentration detection device, detection method and detector

Abstract

The present invention proposes a negative ion collector, a negative ion concentration detection device, a detection method and a detector. The detection device includes a negative ion collector, a collection plate of the negative ion collector is electrically connected to a polarization voltage circuit module capable of generating a gradient-changing polarization voltage through an external interface, and the negative ion collector is electrically connected to the polarization voltage circuit module capable of generating a gradient-changing polarization voltage. By changing the polarization voltage in steps, the conversion relationship between the polarization voltage and the corresponding collection current is found, and a multivariate linear equation group between the polarization voltage and the corresponding current is established. The solution of the equation group is the negative ion concentration value of the corresponding mobility. The present invention also provides a negative ion collector, wherein the collection plate and the polarization plate are respectively fixed on the upper insulating seat surface and the lower insulating seat surface, and the collection plate and the polarization plate are arranged parallel and symmetrically from top to bottom; the external interface is respectively integrated on the collection plate and the polarization plate, and extends out of the closed upper and lower insulating seats through the through hole; the fan is fixed at the cross section of the upper and lower insulating seats.

Description

Technical Field

[0001] The invention relates to the field of meteorology and environmental monitoring, and in particular to an accurate negative ion detection device, a detection method and a detector for specifying multiple mobility. Background Art

[0002] Negative oxygen ions in the air are called "air vitamins". They have the functions of killing bacteria, reducing dust, cleaning the air, improving immunity, and regulating the balance of human body functions. They play an important role in improving the atmospheric environment.

[0003] The concentration of negative ions in the air is an important criterion for judging air quality, and is also an important indicator for identifying the quality of negative ion generators on the market. Traditional negative ion concentration detectors measure the current formed by negative ions at both ends of the collecting plate based on a capacitive ion collector, and convert it based on the relationship between the current value and the negative ion concentration.

[0004] The above-mentioned traditional negative ion concentration detector has an edge effect, that is, near the collecting plate (low migration distance), negative ions below the measured mobility will also be counted. The mobility of negative oxygen ions in the atmosphere is 0.4 (cm 2 / V*s), mobility is less than 0.4(cm 2 / V*s) of negative ions in the air will not be easily absorbed by the human body. Therefore, the detection accuracy of traditional negative ion detectors that ignore the edge effect is defective. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a negative ion concentration detection device, a detection method and a detector capable of accurately detecting the concentrations of negative ions with different mobilities.

[0006] A first aspect of the present invention provides a negative ion concentration detection device, comprising a negative ion collector, wherein a collecting plate of the negative ion collector is electrically connected to a polarization voltage circuit module capable of generating a gradient-varying polarization voltage through an external interface.

[0007] In one embodiment, the gradient-varying polarization voltage is generated by electrically controlled adjustable resistance voltage division.

[0008] In one embodiment, the collection plate is connected to an I / V circuit module via an external interface, and the I / V circuit module converts the charge signal into a voltage signal;

[0009] The I / V circuit module is an integral operation circuit or a cross-group operational amplifier circuit;

[0010] The I / V circuit module is connected to the signal amplification circuit and then connected to the A / D sampling circuit, and the result is transmitted to the MCU single chip computer module through I / O communication.

[0011] In one embodiment, the negative ion concentration detection device also includes a current signal acquisition module, which samples the current signals generated by negative ions by setting multiple groups of different polarization voltages, and stores the results in a matrix array; after changing the polarization voltage n times and sampling the current n times, the processed data is obtained as an n-row and n-column matrix array a[n][n], and an n-row and 1-column current value array b[n]; using the matrix change, the inverse matrix a'[n][n] of the matrix corresponding to the array a[n][n] is obtained; the matrix corresponding to a'[n][n] and the matrix corresponding to b[n] are factorially operated, and the result is stored in ρ[n], and the values ​​ρ1, ρ2, ρ3, ..., ρ in the array ρ[n] are n The value of is the negative ion concentration value with different mobility.

[0012] In one embodiment, the negative ion concentration detection device can sample the current signal corresponding to each polarization voltage 10 to 20 times, and use a recursive average filtering algorithm to achieve a low-jump stable negative ion concentration value. Preferably, each polarization voltage is sampled 20 times, and a recursive average filtering algorithm (N=20) is used to average the corresponding 20 negative ion concentration values, and the obtained negative ion concentration average value is the final negative ion concentration value of the corresponding mobility, thereby achieving a low-jump stable negative ion concentration value.

[0013] In one embodiment, the negative ion concentration detection device further includes a temperature and humidity sampling module for sampling temperature and humidity values ​​to compensate for the negative ion concentration.

[0014] In one embodiment, the negative ion collector includes a shield, a collecting plate, a polarization plate, an upper insulating seat, a lower insulating seat, an external interface and a fan, wherein:

[0015] The collecting plate and the polarizing plate are respectively fixed on the upper insulating seat surface and the lower insulating seat surface, and are arranged parallel and symmetrically up and down;

[0016] The external interfaces are respectively integrated on the collecting plate and the polarizing plate, and extend out of the closed upper and lower insulating seats through the through holes;

[0017] The fan is fixed at the cross sections of the upper and lower insulating seats.

[0018] In one embodiment, the collecting plate and the polarizing plate are provided with metal seats for external circuit connection, and connecting rods of the metal seats and the collecting plate and the polarizing plate extend through small holes to form two clamped insulating seats.

[0019] In one embodiment, the shielding cover is divided into two parts that can be snapped together, the front part is provided with an array of through holes, and the rear part is provided with square through holes.

[0020] The second aspect of the present invention provides a method for detecting negative ion concentration, in which a negative ion collector is electrically connected to a polarization voltage circuit module that can generate a gradient-changing polarization voltage. The polarization voltage is changed in steps, and the conversion relationship between the polarization voltage and the corresponding collection current is found to establish a multivariate linear equation group between the polarization voltage and the corresponding current. The solution of the equation group is the negative ion concentration value of the corresponding mobility.

[0021] In one embodiment, different mobilities μ1, μ2, μ3, ..., μ n , the negative ion concentrations are ρ1, ρ2, ρ3,…, ρ n , the current generated by the negative ion collector is I 1max ,I 2max ,I 3max ,…,I nmax , assuming the first polarization voltage U1, under this condition, the corresponding limit mobility of negative ions generated current I 1max ; The nth polarization voltage U n The generation current I of negative ions corresponding to the limiting mobility nmax ; At polarization voltage U i Under the action, the total current detected is I i , different mobilities (μ1,μ2,μ3,…,μ n ,) The current generated by the negative ions is I i1 ,I i2 ,I i3 ,…,I in ,but:

[0022] I i =I i1 +I i2 +I i3 +…+I in (3)

[0023] I nmax =e*ρ n *V f (4)

[0024] Where e is the electron charge (e≈1.602*10 -19 C), V f is the flow rate of the DC fan. ji with I imax relation:

[0025] I ji =k ji *I imax =k ji *e* f *ρ i (5)

[0026] Among them, k ji The mobility is μ i The negative ions are at the polarization voltage U bn The percentage of ions that can hit the collecting plate under the action of k ji The values ​​are:

[0027]

[0028] In summary,

[0029] I i =e*V f *(k 1i *ρ1+k 2i *ρ2+k 3i *ρ3+…+k ni *ρ n ) (7)

[0030] Among them, I i is obtained through detection and is a known value, e,V f ,K ji Calculated; unknowns are ρ1, ρ2, ρ3,…, ρ n ; By setting n different polarization voltages and obtaining n corresponding current values ​​through the detection circuit, a set of n-dimensional linear equations is established to solve ρ1, ρ2, ρ3,…, ρ n The value of .

[0031] In one embodiment, the algorithm of the negative ion concentration detection method uses a recursive average filtering method to continuously read and calculate 10 to 20 data results and store them in a result queue. When a new data result is placed at the end of the queue, the data at the head of the queue is discarded, and the 10 to 20 data in the queue are arithmetic averaged to obtain a new filtering result to achieve a stable negative ion concentration b[n]. Preferably, the data results are continuously read and calculated 20 times and placed in the result queue, and the 20 data in the queue are arithmetic averaged.

[0032] In one embodiment, the negative ion concentration detection method of the present invention comprises the following steps:

[0033] The digital control adjusts the output polarization voltage, samples the current signal generated by the negative ions, calculates the current value, and stores the current value result in the matrix array;

[0034] Determine whether the polarization voltage has changed n times. If so, use the matrix method to solve the n-variable linear equation group and sample the temperature and humidity. After changing the polarization voltage n times and sampling the current n times, the processed data is obtained as a matrix array a[n][n] with n rows and n columns, and a current value array b[n] with n rows and 1 column; use the matrix change to obtain the inverse matrix a'[n][n] of the matrix corresponding to the array a[n][n]; if not, return to the previous step and re-adjust the output polarization voltage by numerical control;

[0035] Perform factorial operation and temperature and humidity coefficient correction on the matrix corresponding to a'[n][n] and the matrix corresponding to b[n] to obtain the negative ion concentration value, and store the result in the ρ[n] array;

[0036] Sample each polarization voltage N times, and determine ρ[n] N Is N in the array greater than 20? If so, for ρ[n] N The array uses a recursive average filtering algorithm to obtain ρ[n] 1～ ρ[n] 20 The average value, ρ[n] N The array is the final negative ion concentration value; if not, return to continue numerically adjusting the output polarization voltage.

[0037] The third aspect of the present invention provides a negative ion collector, which includes a shield, a collecting plate, a polarization plate, an upper insulating seat, a lower insulating seat, an external interface and a fan, wherein:

[0038] The collecting plate and the polarizing plate are fixed on the upper insulating seat surface and the lower insulating seat surface respectively, and the collecting plate and the polarizing plate are arranged parallel and symmetrically up and down;

[0039] The external interfaces are respectively integrated on the collecting plate and the polarizing plate, and extend out of the closed upper and lower insulating seats through the through holes;

[0040] The fan is fixed at the cross sections of the upper and lower insulating seats.

[0041] In one embodiment, the collecting plate and the polarizing plate are provided with metal seats for external circuit connection, and connecting rods of the metal seats, the collecting plate and the polarizing plate extend through small holes to two clamped upper insulating seats and lower insulating seats.

[0042] In one embodiment, the shielding cover is a metal shielding cover, which includes a front half and a rear half that are movably connected, the front half is provided with an array of through holes, and the rear half is provided with square through holes.

[0043] The fourth aspect of the present invention provides a negative ion concentration detector, including a display screen, wherein the negative ion concentration detector also includes any one or more of the negative ion concentration detection devices described above, or uses any one or more of the negative ion concentration detection methods described above to perform negative ion concentration detection, or includes any one or more of the negative ion collectors described above.

[0044] Compared with the prior art, the negative ion concentration detection device, detection method and detector of the present invention have the following advantages:

[0045] 1. The negative ion concentration detection device of the present invention can eliminate the edge effect and realize accurate display of negative ion concentration;

[0046] 2. The negative ion concentration detection device of the present invention can calculate and display the negative ion concentration values ​​of different mobilities through an algorithm by taking multiple sets of samples with step-wise polarization voltage.

[0047] 3. The negative ion concentration detection device of the present invention realizes the negative ion concentration value of a specified mobility by setting a plurality of different polarization voltage values ​​and combining an algorithm;

[0048] 4. The negative ion concentration detection device of the present invention adopts a recursive average filtering algorithm, which can achieve low jump and stable display of negative ion concentration;

[0049] 5. The negative ion concentration detection device of the present invention can realize the negative ion concentration sampling and display of low temperature and humidity drift by combining temperature and humidity parameter correction;

[0050] 6. The negative ion collector of the present invention is small and compact, and can realize miniaturization of negative ion detection.

[0051] The above-mentioned technical features can be combined in various technically feasible ways to produce new embodiments, as long as the purpose of the present invention can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The invention will be described in more detail below based on non-limiting examples and with reference to the accompanying drawings, in which:

[0053] Figure 1 A schematic diagram showing the migration path of negative ions on the collecting plate in the present invention is shown;

[0054] Figure 2 The edge effect principle diagram of the present invention is shown;

[0055] Figure 3 The schematic diagram of the principle of the negative ion detection device in the present invention is shown;

[0056] Figure 4 A schematic diagram showing the algorithm principle of the negative ion detection device in the present invention is shown;

[0057] Figure 5 The schematic diagram of the structure of the negative ion detector in the present invention is shown;

[0058] Figure 6 A schematic diagram of a negative ion collector shield in the present invention is shown;

[0059] Figure 7 A schematic diagram showing the structure of the negative ion collector in the present invention is shown;

[0060] Figure 8 A schematic diagram showing an exhaust fan used in the negative ion collector of the present invention;

[0061] Fig. 9 A schematic flow chart of the negative ion detection method of the present invention is shown.

[0062] In the figures, the same components are indicated by the same reference numerals. The figures are not drawn to scale.

[0063] Wherein, the accompanying drawings are marked as follows:

[0064] 1. Negative ion collector; 101. Front cover of negative ion collector shielding cover; 102. Back cover of negative ion collector shielding cover; 1011. Array of vent holes on the front cover of shielding cover; 1021. Square vent holes on the back cover of shielding cover; 110. Polarization plate insulating seat; 111. Polarization plate; 112. Polarization plate external interface; 113. Polarization plate mounting screws; 114. Back part fastening screws of polarization plate and collecting plate insulating seat; 115. Front part fastening screws of polarization plate and collecting plate insulating seat; 116. Front part fastening plate of polarization plate and collecting plate insulating seat; 117. Collecting plate insulating seat; 118. Collecting plate; 119. Collecting plate external interface; 1110. Polarizing plate insulating seat mounting screw hole; 1111. Collecting plate insulating seat mounting screw hole; 1112. Collecting plate mounting screw; 1113. Rear fastening plate of polarizing plate and collecting plate insulating seat; 120. Fan; 121. Fan mounting hole; 122. Fan blades; 123. Fan power line and PWM control line; 2. I / V conversion circuit module; 3. Signal amplification module; 4. A / D sampling module; 5. MCU single-chip computer module; 6. Adjustable rheostat MAX5438 chip; 7. Display screen. DETAILED DESCRIPTION

[0065] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, as long as there is no conflict, the various embodiments of the present invention and the various features in the embodiments can be combined with each other, and the technical solutions formed are all within the protection scope of the present invention.

[0066] Parts not described in the present invention can be implemented by adopting or drawing on existing technologies.

[0067] A first aspect of the present invention provides a miniaturized negative ion collector, comprising a polarization plate, a collection plate, an insulating seat, a fixing plate, a DC fan and a shielding cover;

[0068] The polarization plate and the collection plate are stainless steel plates, fixed to the insulating seat surface by screws, placed in parallel, and preferably have a size of 43mm*20mm*1.2mm (length*width*height). The collection plate and the polarization plate have metal seats for connecting external circuits, and the connecting rods of the metal seats and the collection plate and the polarization plate can extend through the small holes to extend out of the two clamped insulating seats.

[0069] The insulating seat is made of insulating material, preferably Teflon material. The insulating seat is processed with screw holes for easy installation and fastening. The insulating seat is divided into an upper collecting plate insulating seat and a lower polarizing plate insulating seat, and the collecting plate insulating seat and the polarizing plate insulating seat can be tightened and sealed by a fixing plate.

[0070] The fixing plate is a stainless steel plate, and the size is preferably 45mm*45mm*1mm (length*width*height). The fixing plate can not only fasten the two insulating seats, but also serve as a connector between the DC fan and the insulating seat, and the DC fan is installed at the cross section of the insulating seat.

[0071] The shielding cover is divided into two parts that can be snapped, the front part is provided with array through holes, and the back part is provided with square through holes. The material of the shielding cover is preferably stainless steel, and the size is preferably 45mm*60mm*45mm (length*width*height).

[0072] The second aspect of the present invention provides a negative ion concentration detection device that can simultaneously and accurately detect different mobilities based on a gradient-varied polarization voltage. The core of realizing this function is to change the polarization voltage in steps, find the conversion relationship between it and the corresponding collection current, and establish a multivariate linear equation system between them. The solution of the equation system is the negative ion concentration value of the corresponding mobility.

[0073] The negative ion concentration detection device of the present invention comprises the negative ion collector provided by the first aspect of the present invention, an I / V conversion circuit, a signal amplification circuit, an A / D sampling circuit, an MCU processor, a polarization voltage regulation circuit and a voltage source circuit.

[0074] In a more specific embodiment:

[0075] The device of the present invention detects negative ions by using an active electric fan to draw air and suck in negative ions for detection; its structure diagram and principle diagram are shown in FIG. Figure 1 shown.

[0076] When negative ions are sucked into the electric field between the collecting plate and the polarizing plate, they migrate toward the collecting plate under the action of the electric field force. The average velocity of the movement in this direction is set to V d In addition, negative ions will also be affected by the negative pressure of the air and move with the air toward the fan. The migration speed of this direction is set as V L , the distance between the collecting plate and the polarizing plate is d, and the length of the collecting plate along the wind speed direction is L. The mobility μ of negative ions refers to the speed value of the uniformly accelerated movement of air negative ions in the air under the action of the electrostatic force generated by the unit field strength.

[0077] μ=V d / E=V d / (U / d)=d*V d / U (1)

[0078] Among them, V d is the migration velocity, E is the electric field strength under the polarization voltage, and U is the polarization voltage.

[0079] If all the negative ions entering the collector can hit the collecting plate, then the negative ions close to the polarization plate will also move to the end of the collecting plate. The mobility of these negative ions is called the limiting mobility μ of the collector under the polarization voltage U. e (like Figure 2 a), then:

[0080] μ e =d*V d / U=d*(d / (L / V L )) / U=d 2 *V L / (L*U) (2)

[0081] At this time, the mobility is higher than μ e Negative ions (small particle size) entering the collector will definitely hit the collecting plate and be detected, and the mobility is lower than μ e The negative ions (large particle size) may be partially collected near the edge of the collecting plate. This phenomenon is called edge effect (e.g. Figure 2 b) Due to the existence of edge effect, even if a low polarization voltage is applied, it is difficult to filter out the negative ion signal with low mobility due to insufficient migration distance in the direction of the electric field.

[0082] Traditional negative ion detection generally gives a given polarization voltage, and the default current signals detected are all higher than the limit mobility μ e The negative ion signal is ignored, and the signal interference caused by the edge effect of low-mobility negative ions is ignored; the detection result is distorted. At the same time, it is also unable to distinguish the concentration of a specific mobility negative ion.

[0083] The negative ion concentration detection device of the present invention adopts a gradient polarization voltage, and according to the corresponding current values, the solution of the multivariate linear equation is solved to obtain the negative ion concentration value corresponding to the mobility. The further process is as follows:

[0084] Set different mobilities (μ1,μ2,μ3,…,μ n ,) (i.e., different scales) of negative ion concentrations are ρ1, ρ2, ρ3,…, ρ n , the current generated by them hitting the collecting plate is I 1max ,I 2max ,I 3max ,…,I nmax , assuming the first polarization voltage U1, under this condition, the corresponding limit mobility of negative ions generated current I 1max (like Figure 3 a); nth polarization voltage U n The generation current I of negative ions corresponding to the limiting mobility nmax (like Figure 3 b) At polarization voltage U i Under the action, the total current detected is I i , different mobilities (μ1,μ2,μ3,…,μ n ,) (i.e., the current generated by negative ions of different scales is I i1 ,I i2 ,I i3 ,…,I in ,but:

[0085] I i =I i1 +I i2 +I i3 +…+I in (3)

[0086] I nmax =e*ρ n *V f (4)

[0087] Where e is the electron charge (e≈1.602*10 -19 C), V f is the flow rate of the DC fan. ji with I imax relation:

[0088] I ji =k ji *I imax =k ji *e* f *ρ i (5)

[0089] Among them, kji The mobility is μ i The negative ions are at the polarization voltage U bn The percentage of ions that can hit the collecting plate under the action of k ji The values ​​are:

[0090]

[0091] In summary,

[0092] l i =e*V f *(k 1i *ρ1+k 2i *ρ2+k 3i *ρ3+…+k ni *ρ n ) (7)

[0093] In equation (7), I i It can be obtained through detection and is a known value, e,V f ,K ji can all be calculated; the unknowns are ρ1, ρ2, ρ3,…, ρ n ; To solve a linear equation with n variables, n equations are needed, that is, n different polarization voltages need to be set, and n corresponding current values ​​need to be obtained through the detection circuit, and a linear equation group with n variables is established to solve ρ1, ρ2, ρ3,…, ρ n The value of .

[0094] In order to realize the above principle, the device of the present invention adopts a digitally controlled variable resistor to divide the voltage to obtain a polarization voltage value with gradient change. The digitally controlled variable resistor is preferably a MAX5438 chip, and the voltage division value is changed through serial communication to obtain a polarization voltage with n steps of change. After each polarization voltage is set, the total current signal is sampled and detected, and the result is stored in a matrix array. After n times of changing the polarization voltage and n times of current sampling, the processed data is obtained as a matrix array a[n][n] with n rows and n columns, and an array b[n] of current values ​​with n rows and 1 column. Using the matrix change, the inverse matrix a'[n][n] of the matrix corresponding to the array a[n][n] is obtained. The matrix corresponding to a'[n][n] is multiplied by the matrix corresponding to b[n], and the result is stored in ρ[n]. The values ​​ρ1, ρ2, ρ3,…, ρ in the array ρ[n] are n The value of is the negative ion concentration corresponding to different mobilities.

[0095] The third aspect of the present invention provides a low-jump, stable negative ion concentration detection device, wherein the preferred algorithm adopts a recursive average filtering method, and the data results are continuously read and calculated 10 to 20 times and stored in the result queue, preferably 20 times. When a new data result is placed at the end of the queue, the data at the head of the queue is discarded. The 20 data in the queue are arithmetic averaged to obtain a new filtering result, thereby achieving a stable display of negative ion concentration.

[0096] In addition, the device of the present invention can be combined with temperature and humidity data for correction, thereby enhancing the detector's ability to resist temperature and humidity interference.

[0097] like Fig. 9 As shown, the fourth aspect of the present invention provides a method for detecting negative ion concentration, and the negative ion concentration detection device of the present invention adopts the following method steps for detection:

[0098] The digital control adjusts the output polarization voltage, samples the current signal generated by the negative ions, calculates the current value, and stores the current value result in the matrix array b[n];

[0099] Determine whether the polarization voltage has changed n times. If so, use the matrix method to solve the n-variable linear equation group and sample the temperature and humidity. After changing the polarization voltage n times and sampling the current n times, the processed data is obtained as a matrix array a[n][n] with n rows and n columns, and an array b[n] of current values ​​with n rows and 1 column. Using the matrix change, obtain the inverse matrix a'[n][n] of the matrix corresponding to the array a[n][n]. If not, return to the previous step and re-adjust the output polarization voltage by numerical control.

[0100] Perform factorial operation and temperature and humidity coefficient correction on the matrix corresponding to a'[n][n] and the matrix corresponding to b[n] to obtain the negative ion concentration value, and store the result in the ρ[n] array. The values ​​in the array ρ[n] are ρ1, ρ2, ρ3, ..., ρ n That is, the negative ion concentration corresponding to different mobility.

[0101] The negative ion concentration detection method of the present invention may also include:

[0102] Each polarization voltage is sampled N times, and the corresponding negative ion concentration value is stored in ρ[n] N Array, judge ρ[n] N Is N in the array greater than 20? If so, for ρ[n] N The array uses a recursive average filtering algorithm to obtain ρ[n] 1～ ρ[n] 20 The average value, ρ[n] N The average value of the array is the final negative ion concentration value corresponding to the mobility; if not, return to continue numerically adjusting the output polarization voltage.

[0103] The fifth aspect of the present invention provides a negative ion concentration detector, comprising a display screen and any one or more of the negative ion detection devices described above for detecting negative ion concentration or using any one or more of the negative ion concentration detection methods described above for detecting negative ion concentration.

[0104] In a more specific embodiment, the main chip of the I / V conversion circuit module and the signal amplification circuit module adopts an OPA111 operational amplifier chip, and the differential input resistance of the chip reaches 10 12 Ω, is a high gain, high input impedance, low zero drift operational amplifier.

[0105] The main chip of the A / D sampling circuit module adopts the CS1237 chip, which is a 24-bit 1-channel voltage sampling chip and integrates temperature sensing. After temperature correction, the influence of temperature drift can be reduced.

[0106] The MCU processor adopts STC8A8K64S4A12 chip, which is a 1T high-cost-effective 51 single-chip microcomputer chip.

[0107] By adopting the above technical solution, the device of the present invention can realize accurate sampling of negative ion concentrations with various mobilities, and can provide data support for atmospheric monitoring and negative ion product quality identification.

[0108] The working principle and working process of the negative ion concentration detection device of the present invention are described below with specific embodiments:

[0109] [Example 1]

[0110] like Figure 5 As shown, it is a structural schematic diagram of the negative ion concentration detector of the present invention, including the negative ion concentration detection device and the display screen of the present invention. The negative ion concentration detection device includes a negative ion collector 1, an I / V conversion circuit 2, a signal amplification circuit 3, an A / D sampling circuit 4, an MCU processor 5, a polarization voltage adjustment circuit 6 and a voltage source circuit 7.

[0111] The schematic diagram of the negative ion collector components is as follows Figure 6 , 7, 8. The shielding cover front cover 101 and the shielding cover rear cover 102 of the negative ion collector are closed by snaps. The shielding cover front cover 101 is provided with a ventilation circular hole array 1011 of the shielding cover front cover and the shielding cover rear cover 102 is provided with ventilation square holes 1021 for guiding the air sucked in by the fan. When the negative ions in the air are sucked into the negative ion collector 1 by the fan 120, the negative ions migrate toward the collecting plate 118 under the action of the electric field generated by the polarization voltage on the polarization plate 111. The collecting plate 118 and the polarization plate 111 are respectively fixed on the insulating seats 117 and 110 by installing screws 112 and 113. In order to facilitate the connection with the external circuit, the collecting plate 118 and the polarization plate 111 are provided with external interfaces 119 and 112 at the same time. The spatial positions of the collecting plate 118 and the polarization plate 111 are parallel and symmetrical up and down. In order to close the air flow path between the collecting plate 118 and the polarizing plate 111, the front fastening plate 116 and the rear fastening plate 1113 are respectively tightened with fastening screws 115 and 114. The rear fastening plate 1113 also serves as a mounting seat for the fan 120, and the fan 120 is mounted on the insulating seat by mounting screws 114. The assembled negative ion collector is placed in a shielding cover and assembled to complete the negative ion collector assembly.

[0112] The polarization plate 110 is connected to the polarization voltage regulating circuit 6 through the external interface 112. The collection plate 118 is connected to the I / V conversion circuit 2 through the external interface 119. The output port of the I / V conversion circuit 2 is connected to the signal amplification circuit 3 to realize voltage signal amplification. The amplified voltage signal is converted into a digital signal through the A / D sampling circuit 4, and the sampling result is communicated with the MCU single-chip computer 5 through the I / O serial port communication. After judging that the data is valid, the single-chip computer 5 stores it in the array. And through the I / O serial port communication, the resistance value of MAX5438 is changed to realize the polarization voltage regulating circuit 6 outputting a new polarization voltage, and a new negative ion detection is performed. The corresponding current value under the action of n different polarization voltages is detected and the result is stored in the matrix array. Through this, an n-dimensional linear equation group can be obtained. The corresponding mobility negative ion concentration value is calculated by solving the inverse matrix through the matrix method. According to the above steps, repeat 20 times, obtain 20 groups of results, and put them into the array queue. The recursive average filtering method is used to obtain the negative ion concentration value with low jump and stability. The MCU single chip 5 sends the concentration value in binary code to the liquid crystal display screen 7 of the negative ion concentration detector to display the final detection result.

[0113] [Example 2]

[0114] As shown in the first embodiment, the I / V conversion circuit 2 uses an integration circuit, that is, a low-capacitance capacitor (100pF) is selected as the charge quantity to be converted into a voltage value. That is:

[0115]

[0116] The I / V conversion circuit of the embodiment adopts the integration circuit technology which is relatively mature and has high precision. However, in order to ensure the precision, it is necessary to select an operational amplifier with high input impedance.

[0117] In this implementation example, the I / V conversion circuit 2 can use direct transimpedance amplification, that is, replace the jumper capacitor with a large resistor to achieve I / V conversion.

[0118] U=-R*I (9)

[0119] This implementation example can avoid the integration error caused by the input offset voltage, input bias current and offset current of the op amp, and also avoid the error caused by the leakage current of the capacitor. However, it has high requirements on the precision of the resistor and the op amp.

[0120] [Example 3]

[0121] Assume that the mobility to be read is 1.0 (cm 2 / V*s),0.4(cm 2 / V*s), 0.2(cm 2 / V*s) are ρ1, ρ2, ρ3 respectively. Fan air volume V f =40cm 3 / s; the distance between the collecting plate and the polarizing plate d = 2 cm; the length of the collecting plate along the wind speed direction L = 4.5 cm; the width of the air inlet interface H = 4.5 cm; the migration speed of negative ions along the wind direction V L =V f / (d*H)=4.44cm / s; According to equation (2), the required polarization voltages (U1, U2, U3) can be calculated to be 3.951V, 9.875V, and 19.753V respectively.

[0122] Assuming that the polarization voltages are U1, U2, and U3, the total currents I1, I2, and I3 of negative ion generation are 1.384*10 -12 A, 1.538*10 -12 A, 1.602*10 -12 A.

[0123] Then, according to equation (7), we can get the following equations:

[0124]

[0125] Solving, we can get

[0126] ρ1=20*10 4 ;ρ2=3*10 4 ;ρ1=2*10 4 .

[0127] In summary, three different polarization voltages can be set, and the corresponding current values ​​obtained by combining sampling conversion are used to establish a set of equations, and the negative ion concentrations with three different mobilities are obtained by solving them.

[0128] At this point, it should be appreciated by those skilled in the art that, although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A negative ion concentration detection device, comprising a negative ion collector, characterized in that: The collecting plate of the negative ion collector is electrically connected to a polarization voltage circuit module capable of generating a gradient-varying polarization voltage through an external interface; The negative ion concentration detection device also includes a current signal acquisition module, which samples the current signals generated by negative ions by setting multiple groups of different polarization voltages, and stores the results in a matrix array; after changing the polarization voltage n times and sampling the current n times, the processed data is obtained as a matrix array a[n][n] with n rows and n columns, and a current value array b[n] with n rows and 1 column; using the matrix change, the inverse matrix a'[n][n] of the matrix corresponding to the array a[n][n] is obtained; the matrix corresponding to a'[n][n] and the matrix corresponding to b[n] are factorially operated, and the result is stored in ρ[n], and the values ​​ρ1, ρ2, ρ3, ..., ρ in the array ρ[n] are n That is, the negative ion concentration value corresponding to different mobility; The negative ion concentration detection device also includes a temperature and humidity sampling module for sampling temperature and humidity values ​​to compensate for the negative ion concentration.

2. The negative ion concentration detection device according to claim 1, characterized in that: The gradient-varying polarization voltage is generated by electrically controlled adjustable resistance voltage division.

3. The negative ion concentration detection device according to claim 1 or 2, characterized in that: The collecting plate is connected to an I / V circuit module via an external interface, and the I / V circuit module converts the charge signal into a voltage signal; The I / V circuit module is an integral operation circuit or a cross-group operational amplifier circuit; The I / V circuit module is connected to the signal amplification circuit and then connected to the A / D sampling circuit, and the result is transmitted to the MCU single chip computer module through I / O communication.

4. The negative ion concentration detection device according to claim 1, characterized in that: The negative ion concentration detection device can sample the current signal corresponding to each polarization voltage 10 to 20 times, and obtain the average value of the corresponding negative ion concentration by using a recursive average filtering algorithm for the corresponding negative ion concentration value, thereby achieving a low-jump stable negative ion concentration value.

5. The negative ion concentration detection device according to claim 1, characterized in that: The negative ion collector comprises a shielding cover, a collecting plate, a polarization plate, an upper insulating seat, a lower insulating seat, an external interface and a fan, wherein: The collecting plate and the polarizing plate are fixed on the upper insulating seat surface and the lower insulating seat surface respectively, and the collecting plate and the polarizing plate are arranged parallel and symmetrically up and down; The external interfaces are respectively integrated on the collecting plate and the polarizing plate, and extend out of the closed upper and lower insulating seats through the through holes; The fan is fixed at the cross sections of the upper and lower insulating seats.

6. The negative ion concentration detection device according to claim 5, characterized in that: The collecting plate and the polarizing plate are provided with metal seats for connecting external circuits, and connecting rods of the metal seats, the collecting plate and the polarizing plate extend through small holes to form two clamped upper insulating seats and lower insulating seats.

7. The negative ion concentration detection device according to claim 5 or 6, characterized in that: The shielding cover is a metal shielding cover, which includes a front half and a rear half that are movably connected. The front half is provided with array through holes, and the rear half is provided with square through holes.

8. A method for detecting negative ion concentration, characterized in that: The negative ion collector is electrically connected to a polarization voltage circuit module capable of generating a gradient-changing polarization voltage. By changing the polarization voltage in steps, the conversion relationship between the polarization voltage and the corresponding collection current is found, and a multivariate linear equation system between the polarization voltage and the corresponding current is established. The solution of the equation system is the negative ion concentration value of the corresponding mobility. Wherein, the negative ion concentration detection method comprises the following steps: The digital control adjusts the output polarization voltage, samples the current signal generated by the negative ions, calculates the current value, and stores the current value in the matrix array b[n]; Determine whether the polarization voltage has changed n times. If so, use the matrix method to solve the n-dimensional linear equation group, and sample the temperature and humidity at the same time. After changing the polarization voltage n times and sampling the current n times, the processed data is obtained as a matrix array a[n][n] with n rows and n columns, and an array b[n] of current values ​​with n rows and 1 column. Use the matrix change to obtain the inverse matrix a'[n][n] of the matrix corresponding to the array a[n][n]. If not, return to the previous step and re-adjust the output polarization voltage by numerical control. Perform factorial operation and temperature and humidity coefficient correction on the matrix corresponding to a'[n][n] and the matrix corresponding to b[n] to obtain the negative ion concentration value, and store the result in the ρ[n] array. The value in the ρ[n] array is the negative ion concentration value corresponding to the mobility; The negative ion concentration detection method also includes sampling temperature and humidity values ​​to compensate for the negative ion concentration and improve the accuracy of the negative ion concentration.

9. The method for detecting negative ion concentration according to claim 8, characterized in that: Set different mobilities μ1,μ2,μ3,…,μ n The negative ion concentrations are ρ1, ρ2, ρ3,…, ρ n , the current generated by the negative ion collector is I 1max ,I 2max ,I 3max ,…,I nmax , assuming the first polarization voltage U1, under this condition, the corresponding limit mobility of negative ions generated current I 1max ; The nth polarization voltage U n The generation current I of negative ions corresponding to the limiting mobility nmax ; At polarization voltage U i Under the action, the total current detected is I i , the current generated by negative ions with different mobility is I i1 ,I i2 ,I i3 ,…,I in ,but: I i =I i1 +I i2 +I i3 +…+I in I nmax =e*ρ n *V f Where e is the electron charge, V f is the flow rate of the DC fan, I ji with I imax relation: I ji =k ji *I imax =k ji *e*V f *ρ i Among them, k ji The mobility is μ i The negative ions are at the polarization voltage U bn The percentage of ions that can hit the collecting plate under the action of k ji The values ​​are: In summary, I i =e*V f *(k 1i *p1+k 2i *p2+k 3i *p3+…+k ni *r n ) Among them, I i is obtained through detection and is a known value, e,V f ,K ji Calculated; unknowns are ρ1, ρ2, ρ3,…, ρ n ; By setting n different polarization voltages and obtaining n corresponding current values ​​through the detection circuit, a set of n-dimensional linear equations is established to solve ρ1, ρ2, ρ3,…, ρ n The value of .

10. The method for detecting negative ion concentration according to claim 8 or claim 9, characterized in that: The algorithm of the negative ion concentration detection method adopts a recursive average filtering method, samples the current signal corresponding to each polarization voltage 10 to 20 times, calculates the corresponding negative ion concentration value and puts it into a queue, performs arithmetic averaging on the 10 to 20 data in the queue, and the obtained average negative ion concentration value is the final negative ion concentration value of the corresponding mobility.

11. The method for detecting negative ion concentration according to claim 8, characterized in that: The negative ion concentration detection method also includes: Each polarization voltage is sampled N times, and the corresponding negative ion concentration value is stored in ρ[n] N Array, judge ρ[n] N Is N in the array greater than 20? If so, for ρ[n] N The array uses a recursive average filtering algorithm to obtain ρ[n] 1～ ρ[n] 20 The average value, ρ[n] N The average value of the array is the final negative ion concentration value corresponding to the mobility; if not, the process returns to continue numerically adjusting the output polarization voltage and performing current sampling.

12. A negative ion concentration detector, comprising a display screen, characterized in that: The negative ion concentration detector also includes the negative ion concentration detection device according to any one of claims 1-7 or uses the negative ion concentration detection method according to any one of claims 8-11 to perform negative ion concentration detection.

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