A control system and method for oxygen balance of oxygen concentrator

Abstract

A method and system for controlling oxygen balance of an oxygen concentrator, comprising the following steps: respectively obtaining flow rates of an oxygen inhalation port and a diffusion purification outlet, and marking them as a first flow rate and a second flow rate respectively; detecting whether there is a change in the first flow rate, and if so, obtaining a change value; judging whether the change value is greater than a preset value, and if so, updating the first flow rate according to the change value, and if so, maintaining the value of the first flow rate; when the value of the first flow rate is updated, obtaining the temperature and compressor parameters of the oxygen concentrator, and calculating the oxygen output flow rate through the temperature and the compressor parameters, and obtaining the sum of the first flow rate and the second flow rate as the oxygen consumption flow rate; judging whether the oxygen consumption flow rate is greater than the oxygen output flow rate, and if so, obtaining the flow difference between the two, and controlling the motor corresponding to the air duct valve of the diffusion purification outlet to operate according to the flow difference, and if less than the oxygen output flow rate, maintaining the opening and closing degree of the air duct of the diffusion purification outlet.

Description

Technical Field

[0001] The invention relates to the technical field of regulating systems, and in particular to a control system and method for oxygen balance of an oxygen concentrator. Background Art

[0002] Molecular sieve oxygen concentrators are generally used in the medical field to provide patients with high-concentration oxygen. With the continuous development of science and technology, oxygen concentrators are also used in the home field. The home oxygen concentrator differentiates the traditional oxygen inlet and the diffusion purification outlet at the oxygen output end, and sets a negative ion generator at the diffusion purification outlet. The negative ion generator combines with high-concentration oxygen to produce negative air ions that are beneficial to the human body.

[0003] However, since the oxygen is decomposed, and the volume of the adsorption tower of the household oxygen concentrator is relatively small due to the limitation of volume, the oxygen content is also relatively small, and during the exchange of the adsorption tower, part of the oxygen in the adsorption tower needs to be decomposed and blown to another adsorption tower for desorption of nitrogen. Therefore, when generating negative air ions and purifying the air, it may affect the oxygen output of the traditional oxygen inlet, and it is impossible to meet the user's oxygen inhalation needs and air purification needs at the same time. Therefore, how to automatically adjust the air outlet balance of the oxygen concentrator has become an urgent problem to be solved by existing household oxygen concentrators. Summary of the invention

[0004] In view of the above-mentioned defects, the purpose of the present invention is to propose a control system and method for oxygen balance of an oxygen concentrator, so as to solve the problem of difficulty in balancing the demand for air purification and oxygen inlet and improve the degree of automation of equipment adjustment.

[0005] To achieve this purpose, the present invention adopts the following technical solution: a method for controlling oxygen balance of an oxygen concentrator, comprising the following steps:

[0006] Step S1: respectively obtaining the flow rates of the oxygen inlet and the diffusion purification outlet, and marking them as the first flow rate and the second flow rate respectively;

[0007] Step S2: Detect whether there is a change in the first flow rate, and if there is a change, obtain a change value;

[0008] Determine whether the change value is greater than a preset value, if so, update the first flow rate according to the change value, if less than, maintain the value of the first flow rate;

[0009] Step S3: when the value of the first flow rate is updated, the temperature and compressor parameters in the oxygen concentrator are obtained, and the oxygen output flow rate is calculated according to the temperature and the compressor parameters, and step S4 is executed;

[0010] Step S4: Obtain the sum of the first flow rate and the second flow rate as the oxygen consumption flow rate; determine whether the oxygen consumption flow rate is greater than the oxygen output flow rate, if greater, obtain the flow difference between the two, and control the motor corresponding to the air duct valve of the diffusion purification outlet to operate according to the flow difference; if less than the oxygen output flow rate, maintain the opening and closing degree of the air duct of the diffusion purification outlet.

[0011] Preferably, the step of calculating the oxygen output flow rate in step S3 is as follows:

[0012] Obtain the standard oxygen output flow rate marked on the oxygen concentrator when it leaves the factory, marked as the third flow rate;

[0013] Determine whether the temperature is greater than a temperature threshold, if so, obtain a first parameter as a temperature adjustment parameter according to the temperature interval, and if less than a second parameter as a temperature adjustment parameter;

[0014] Obtaining the exhaust mass flow rate of the first compression cylinder in the compressor, the intake mass flow rate of the adjacent compression cylinder, the exhaust mass flow rate, and the intake mass flow rate of the last compression cylinder;

[0015] Obtaining a first difference between the exhaust mass flow of adjacent compression cylinders and the intake mass flow of adjacent compression cylinders, if the first difference falls within the range threshold, obtaining a third parameter as the airflow adjustment parameter, if it does not fall within the range threshold, obtaining a second difference between the first difference and the edge value of the range threshold, obtaining the sum of the absolute values ​​of all the second differences as the second difference sum, and obtaining a fourth parameter as the airflow adjustment parameter according to the interval where the second difference sum is located;

[0016] The oxygen output flow rate is obtained by multiplying the airflow adjustment parameter and the temperature adjustment parameter by the third flow rate.

[0017] Preferably, the exhaust mass flow rate and the intake mass flow rate are obtained as follows:

[0018] The inner diameter of the compression cylinder and the stroke of the piston are obtained, and the theoretical working volume of the compression cylinder is obtained through the inner diameter and the piston, wherein the acquisition of the theoretical working volume is shown as follows:

[0019] ;

[0020] Where D is the cylinder diameter, S is the piston stroke, and V is the theoretical working volume;

[0021] Based on the working cycle signal of the compression cylinder, the average intake pressure in the compression cylinder within one cycle is obtained;

[0022] The volume V1 of the compression cylinder during air intake is obtained, the final intake pressure P1 is obtained through the volume V1 and the temperature during air intake, and the compression ratio is obtained based on the final intake pressure P1 and the average intake pressure;

[0023] The formula for obtaining the intake end pressure P1 is as follows:

[0024] ;

[0025] Where n is the number of moles, R is the gas constant of air, T1 is the temperature at intake, and V1 is the volume of the compression cylinder at intake;

[0026] The compression ratio r is obtained by the following formula:

[0027] ;

[0028] in is the average intake pressure, is the temperature variability index;

[0029] The exhaust mass flow rate is obtained by the theoretical working volume and the compression ratio, and the intake mass flow rate is obtained by the theoretical working volume and the exhaust mass flow rate;

[0030] The formulas for obtaining the exhaust mass flow rate and the intake mass flow rate are as follows:

[0031] ;

[0032] ;

[0033] Where V is the theoretical working volume, is the exhaust mass flow rate, is the intake air mass flow rate.

[0034] Preferably, the steps of controlling the motor corresponding to the air duct valve of the diffusion purification outlet by the flow difference in step S4 are as follows:

[0035] The flow difference is input into the first neural network to obtain the opening and closing degree required for the air duct valve to reduce the flow difference;

[0036] The opening and closing degree and adjustment time are input into the PID controller to control the motor.

[0037] Preferably, the structure of the first neural network is as follows:

[0038] The input layer of the first neural network takes the flow difference as input;

[0039] The hidden layer is linearly transformed with the weight matrix W1 and the bias b1, and then the hidden layer output is obtained through the activation function f1;

[0040] Finally, the output layer performs a linear transformation with the hidden layer output, weight matrix W2 and bias b2 to obtain the opening and closing degree;

[0041] The specific hidden layer output H is as follows:

[0042] ;

[0043] The formula for obtaining the opening and closing degree is as follows:

[0044] ;

[0045] in , , are the proportional coefficients respectively, and H is the hidden layer output;

[0046] In the PID controller, the formula for obtaining the motor speed is as follows:

[0047] ;

[0048] in For the required opening and closing degree, , , are the gains of the PID controller, To adjust the time, It is the accumulation of the opening and closing error values ​​of the air duct valve that did not reach the specified opening and closing degree after the motor speed was adjusted in the past.

[0049] A control system for oxygen balance of an oxygen concentrator, using the control method for oxygen balance of an oxygen concentrator, comprising a consumption flow acquisition module, a detection module, an output flow acquisition module and a regulation module;

[0050] The consumption flow acquisition module is used to respectively acquire the flow of the oxygen inhalation port and the diffusion purification outlet, which are marked as the first flow and the second flow respectively;

[0051] The detection module is used to detect whether there is a change in the first flow rate, and if there is a change, obtain the change value;

[0052] Determine whether the change value is greater than a preset value, if so, update the first flow rate according to the change value, if less than, maintain the value of the first flow rate;

[0053] The output flow acquisition module is used to obtain the temperature and compressor parameters in the oxygen concentrator when the value of the first flow changes, and calculate the oxygen output flow through the temperature and compressor parameters, and call the adjustment module;

[0054] The regulating module is used to obtain the sum of the first flow rate and the second flow rate as the oxygen consumption flow rate; determine whether the oxygen consumption flow rate is greater than the oxygen output flow rate, if greater, obtain the flow difference between the two, and control the motor corresponding to the air duct valve of the diffusion purification outlet to operate according to the flow difference; if less than the oxygen output flow rate, maintain the opening and closing degree of the air duct of the diffusion purification outlet.

[0055] Preferably, the output flow acquisition module includes a standardization submodule, a temperature parameter acquisition submodule, an airflow parameter acquisition submodule and a calculation submodule;

[0056] The standardization submodule is used to obtain the standard oxygen output flow rate marked when the oxygen concentrator leaves the factory, which is marked as the third flow rate;

[0057] The temperature parameter acquisition submodule is used to determine whether the temperature is greater than a temperature threshold, and if so, to obtain a first parameter as a temperature adjustment parameter according to the temperature interval; if less than, to obtain a second parameter as a temperature adjustment parameter;

[0058] The airflow parameter acquisition submodule is used to acquire the exhaust mass flow of the first compression cylinder in the compressor, the intake mass flow of the adjacent compression cylinders, the exhaust mass flow, and the intake mass flow of the last compression cylinder;

[0059] Obtaining a first difference between the exhaust mass flow of adjacent compression cylinders and the intake mass flow of adjacent compression cylinders, if the first difference falls within the range threshold, obtaining a third parameter as the airflow adjustment parameter, if it does not fall within the range threshold, obtaining a second difference between the first difference and the edge value of the range threshold, obtaining the sum of the absolute values ​​of all the second differences as the second difference sum, and obtaining a fourth parameter as the airflow adjustment parameter according to the interval where the second difference sum is located;

[0060] The calculation submodule is used for obtaining the oxygen output flow rate by multiplying the airflow adjustment parameter and the temperature adjustment parameter by the third flow rate.

[0061] Preferably, the airflow parameter acquisition submodule includes a first unit, a second unit, a third unit and a fourth unit;

[0062] The first unit is used to obtain the inner diameter of the compression cylinder and the stroke of the piston, and obtain the theoretical working volume of the compression cylinder through the inner diameter and the piston;

[0063] The second unit is used to obtain the average intake pressure in the compression cylinder within one cycle based on the working cycle signal of the compression cylinder;

[0064] The third unit is used to obtain the volume V1 of the compression cylinder during air intake, obtain the final intake pressure P1 through the volume V1 and the temperature during air intake, and obtain the compression ratio based on the final intake pressure P1 and the average intake pressure;

[0065] The fourth unit is used to obtain the exhaust mass flow rate through the theoretical working volume and the compression ratio, and obtain the intake mass flow rate through the theoretical working volume and the exhaust mass flow rate;

[0066] Preferably, the regulating module includes an opening and closing degree acquisition submodule and a speed control submodule;

[0067] The opening and closing degree acquisition submodule is used to input the flow difference into the first neural network to obtain the opening and closing degree required for the air duct valve to reduce the flow difference;

[0068] The speed control submodule is used to input the opening and closing degree and the adjustment time into the PID controller to realize the control of the motor.

[0069] One of the above technical solutions has the following advantages or beneficial effects: by obtaining the flow difference between the oxygen consumption flow and the oxygen output flow, and reducing the flow of the diffusion purification outlet by the flow difference, the oxygen consumption flow and the oxygen output flow can be balanced. That is, the oxygen inhalation needs of the user can be met, and the air purification function can be turned on to the maximum to a certain extent. Improve the degree of automation of the equipment adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 is a flow chart of an embodiment of the method of the present invention.

[0071] Figure 2 It is a schematic diagram of the structure of an embodiment of the system of the present invention.

[0072] Figure 3 It is a working principle diagram of a molecular sieve oxygen generator according to an embodiment of the present invention. DETAILED DESCRIPTION

[0073] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0074] In the description of the embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0075] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0076] like Figure 1 As shown, a method for controlling oxygen balance of an oxygen concentrator comprises the following steps:

[0077] Step S1: respectively obtaining the flow rates of the oxygen inlet and the diffusion purification outlet, and marking them as the first flow rate and the second flow rate respectively;

[0078] Step S2: Detect whether there is a change in the first flow rate, and if there is a change, obtain a change value;

[0079] Determine whether the change value is greater than a preset value, if so, update the first flow rate according to the change value, if less than, maintain the value of the first flow rate;

[0080] Step S3: when the value of the first flow rate is updated, the temperature and compressor parameters in the oxygen concentrator are obtained, and the oxygen output flow rate is calculated according to the temperature and the compressor parameters, and step S4 is executed;

[0081] Step S4: Obtain the sum of the first flow rate and the second flow rate as the oxygen consumption flow rate; determine whether the oxygen consumption flow rate is greater than the oxygen output flow rate, if greater, obtain the flow difference between the two, and control the motor corresponding to the air duct valve of the diffusion purification outlet to operate according to the flow difference; if less than the oxygen output flow rate, maintain the opening and closing degree of the air duct of the diffusion purification outlet.

[0082] In order to balance the flow rates of the oxygen inlet and the diffusion purification outlet so that the oxygen inlet can meet the oxygen inhalation needs of the user, in the present invention, the flow rates of the oxygen inlet and the diffusion purification outlet are respectively obtained when the oxygen generator starts to output oxygen. Since the oxygen in the oxygen inlet is not consumed at the moment of outputting oxygen, the flow rate at the oxygen inlet at this time can be defaulted to the initialized flow rate. When the first flow rate changes, it may be due to external force collision or a user is really using the oxygen inlet. In the case of accidents such as external force collision, the oxygen inlet is not actually used for oxygen inhalation, so there is no oxygen flow demand at this time. In addition, the first flow rate change value caused by unexpected reasons such as external force collision will be relatively small. Therefore, a preset value can be set in advance. By judging whether the change value is greater than the preset value, it can be judged whether the cause of the change in the first flow rate is the accidental influence of external force or the user is using it.

[0083] When the user is using the oxygen inhalation port to inhale oxygen, the temperature in the oxygen concentrator and the compressor parameters are obtained at the same time to calculate the output flow rate of oxygen. By comparing the oxygen output flow rate with the oxygen consumption flow rate, it is immediately determined whether the current oxygen is over-consumed. If the oxygen consumption flow rate is greater than the oxygen output flow rate, it means that the oxygen consumption is excessive, which may cause the oxygen flow rate at the oxygen inhalation port to fail to meet the user's needs. To this end, it is necessary to obtain the flow difference between the oxygen consumption flow rate and the oxygen output flow rate. After reducing the flow rate difference of the diffusion purification outlet, the oxygen consumption flow rate can be balanced with the oxygen output flow rate. That is, it meets the user's oxygen inhalation needs, and it can also ensure that the air purification function can be turned on to the maximum to a certain extent. Improve the degree of automation of the equipment's adjustment.

[0084] It is worth mentioning that Figure 3 As shown, the oxygen concentrator used in the present invention has requirements for the location of the compressor housing. It must be set outdoors. If it is set in an indoor environment, the indoor environment is relatively tightly sealed, and the efficiency of external air replenishment to the indoor environment is low. If the oxygen concentrator is used for a long time, it will affect the concentration of indoor oxygen content. Although the first flow rate and the second flow rate can meet the demand in terms of flow rate, the output oxygen concentration cannot be ensured in terms of concentration. When the compressor housing is set outdoors, the nitrogen in the outdoor air can be fully filtered to ensure that the output oxygen concentration meets the demand.

[0085] Preferably, the step of calculating the oxygen output flow rate in step S3 is as follows:

[0086] Obtain the standard oxygen output flow rate marked on the oxygen concentrator when it leaves the factory, marked as the third flow rate;

[0087] Determine whether the temperature is greater than a temperature threshold, if so, obtain a first parameter as a temperature adjustment parameter according to the temperature interval, and if less than a second parameter as a temperature adjustment parameter;

[0088] Obtaining the exhaust mass flow rate of the first compression cylinder in the compressor, the intake mass flow rate of the adjacent compression cylinder, the exhaust mass flow rate, and the intake mass flow rate of the last compression cylinder;

[0089] Obtaining a first difference between the exhaust mass flow of adjacent compression cylinders and the intake mass flow of adjacent compression cylinders, if the first difference falls within the range threshold, obtaining a third parameter as the airflow adjustment parameter, if it does not fall within the range threshold, obtaining a second difference between the first difference and the edge value of the range threshold, obtaining the sum of the absolute values ​​of all the second differences as the second difference sum, and obtaining a fourth parameter as the airflow adjustment parameter according to the interval where the second difference sum is located;

[0090] The oxygen output flow rate is obtained by multiplying the airflow adjustment parameter and the temperature adjustment parameter by the third flow rate.

[0091] There are two factors that affect the oxygen production of the oxygen generator, one is temperature and the other is the compressor. Temperature will affect the adsorption of nitrogen by the adsorption tower, thereby affecting the output concentration of oxygen and ultimately affecting the output flow rate of oxygen. The compressor will affect the output flow rate due to aging or pipeline leakage. For this reason, in the present invention, it is first necessary to collect the standard oxygen output flow rate marked on the oxygen generator when it leaves the factory. Then obtain the operating temperature of the oxygen generator. Under normal temperature, the adsorption tower can fully and effectively adsorb nitrogen. At this time, the second parameter is selected as the temperature adjustment parameter, and the second parameter is 1. When the temperature is higher than the temperature threshold, the first parameter is selected as the temperature adjustment parameter. There is a linear relationship between the change in temperature and the adsorption of nitrogen by the adsorption tower. Therefore, the first parameter can be determined by measuring the adsorption percentage of nitrogen by the adsorption tower at different temperatures. The value of the first parameter is finally determined. Due to the different materials of different adsorption towers, the values ​​of the first parameter corresponding to their temperatures are also different. No excessive restrictions are made here.

[0092] Regarding the aging and leakage problems of the compressor, the present invention mainly detects the amount of air transferred between the various compression cylinders of the compressor to determine whether the compressor is aged. In the absence of aging and leakage, the exhaust mass flow rate of the previous compression cylinder is equal to the intake mass flow rate of the next compression cylinder. Of course, this value has a certain deviation due to factors such as temperature and humidity. For this reason, the first difference between the exhaust mass flow rate of adjacent compression cylinders and the intake mass flow rate of adjacent compression cylinders is obtained in the present invention, and the first difference is used to determine whether it falls into the range threshold. If both fall into the range, it means that there is no aging and leakage problem in the compressor at present. At this time, the third parameter is used as the airflow adjustment parameter, and the value of the third parameter is 1. If it does not fall into the range, the second difference between the first difference and the edge value of the range threshold is obtained, and the sum of the absolute values ​​of all the second differences is obtained as the second difference sum. The fourth parameter is obtained according to the interval where the second difference sum is located as the airflow adjustment parameter. The following is an example for explanation:

[0093] For example, a four-cylinder compressor is used for illustration. Assuming that the range threshold is 0.2~-0.2, the exhaust mass flow of compression cylinder 1 and the intake mass flow of compression cylinder 2 are first calculated to obtain the first first difference. If the first difference is -0.19, the first difference falls within the threshold range. Then the exhaust mass flow of compression cylinder 2 and the intake mass flow of compression cylinder 3 are calculated to obtain the second first difference. If the second first difference is 0.5, the second difference between the second first difference 0.5 and the range threshold edge value 0.2 is obtained. At this time, the first second difference is 0.3 (if it is a negative number, -0.2 is obtained as the range threshold edge value). Similarly, the third first difference is obtained. If the third first difference is -0.3, the second difference between the third first difference -0.3 and the range threshold edge value -0.2 is obtained. At this time, the second second difference is -0.1. Since the final oxygen output flow rate will be reduced regardless of whether there is a problem with the intake or exhaust, the absolute values ​​of multiple second differences will be added to obtain the second difference sum. At this time, the absolute value of the first second difference 0.3 is added to the absolute value of the second second difference -0.1 to obtain the second difference sum of 0.4. At this time, the second difference sum represents the leaked gas data, and there is a linear relationship between the leaked gas data and the final oxygen output flow rate. Therefore, the fourth parameter corresponding to different second difference sums can be obtained through multiple sets of tests.

[0094] Finally, the oxygen output flow rate is estimated by multiplying the airflow adjustment parameter and the temperature adjustment parameter by the third flow rate.

[0095] Preferably, the exhaust mass flow rate and the intake mass flow rate are obtained as follows:

[0096] The inner diameter of the compression cylinder and the stroke of the piston are obtained, and the theoretical working volume of the compression cylinder is obtained through the inner diameter and the piston, wherein the acquisition of the theoretical working volume is shown as follows:

[0097] ;

[0098] Where D is the cylinder diameter, S is the piston stroke, and V is the theoretical working volume;

[0099] Based on the working cycle signal of the compression cylinder, the average intake pressure in the compression cylinder within one cycle is obtained;

[0100] The volume V1 of the compression cylinder during air intake is obtained, the final intake pressure P1 is obtained through the volume V1 and the temperature during air intake, and the compression ratio is obtained based on the final intake pressure P1 and the average intake pressure;

[0101] The formula for obtaining the intake end pressure P1 is as follows:

[0102] ;

[0103] Where n is the number of moles, R is the gas constant of air, T1 is the temperature at intake, and V1 is the volume of the compression cylinder at intake;

[0104] The compression ratio r is obtained by the following formula:

[0105] ;

[0106] in is the average intake pressure, is the temperature variability index;

[0107] The exhaust mass flow rate is obtained by the theoretical working volume and the compression ratio, and the intake mass flow rate is obtained by the theoretical working volume and the exhaust mass flow rate;

[0108] The formulas for obtaining the exhaust mass flow rate and the intake mass flow rate are as follows:

[0109] ;

[0110] ;

[0111] Where V is the theoretical working volume, is the exhaust mass flow rate, is the intake air mass flow rate.

[0112] In the present invention, the exhaust mass flow rate and the intake mass flow rate are not obtained by a flow meter. Since the oxygen concentrator used at home is small, the compression cylinders are not directly connected by flanges (connecting by flanges will increase the volume), so adjacent compression cylinders are connected by pipes. If a flow meter is used for detection, different flow data will be collected due to the installation position of the flow, so that the corresponding exhaust mass flow rate and intake mass flow rate cannot be accurately obtained. For this reason, in the present invention, the average intake pressure in each compression cylinder within one cycle is obtained. Finally, the exhaust mass flow rate is obtained by the theoretical working volume and the compression ratio, and the intake mass flow rate is obtained by the theoretical working volume and the exhaust mass flow rate. This method can avoid the problem that the exhaust mass flow rate and the intake mass flow rate are affected by the setting position of the flow meter, and greatly improves the accuracy of the data.

[0113] Preferably, the steps of controlling the motor corresponding to the air duct valve of the diffusion purification outlet by the flow difference in step S4 are as follows:

[0114] The flow difference is input into the first neural network to obtain the opening and closing degree required for the air duct valve to reduce the flow difference;

[0115] The opening and closing degree and adjustment time are input into the PID controller to control the motor.

[0116] Since the relationship between the flow difference and the speed of the motor is not linear, it is difficult to control the motor to rotate through traditional calculation methods, so that the opening and closing degree of the air duct valve meets the requirements. For this reason, in the present invention, the flow difference is converted into the opening and closing degree required for the air duct valve to reduce the flow difference through the first neural network. There is a linear relationship between the opening and closing degree of the air duct valve and the number of turns of the motor. However, due to the aging of the motor and other temperatures, the present invention does not obtain the speed of the motor through a simple linear relationship, but inputs the opening and closing degree and the adjustment time into the trained PID controller again. The PID controller is provided with a corresponding error adjustment, which can obtain the speed of motors with different usage degrees, so that the air duct valve can be adjusted to the corresponding opening and closing degree within the adjustment time. By combining neural networks and PID controllers, the accuracy, adaptability, stability and robustness of control can be improved.

[0117] Preferably, the structure of the first neural network is as follows:

[0118] The input layer of the first neural network takes the flow difference as input;

[0119] The hidden layer is linearly transformed with the weight matrix W1 and the bias b1, and then the hidden layer output is obtained through the activation function f1 (such as ReLU or sigmoid);

[0120] Finally, the output layer performs a linear transformation with the hidden layer output, weight matrix W2 and bias b2 to obtain the opening and closing degree;

[0121] The specific hidden layer output H is as follows:

[0122] ;

[0123] The formula for obtaining the opening and closing degree is as follows:

[0124] ;

[0125] in , , are the proportional coefficients respectively, and H is the hidden layer output;

[0126] In the PID controller, the formula for obtaining the motor speed is as follows:

[0127] ;

[0128] in For the required opening and closing degree, , , are the gains of the PID controller, To adjust the time, It is the accumulation of the opening and closing error values ​​of the air duct valve that did not reach the specified opening and closing degree after the motor speed was adjusted in the past.

[0129] A control system for oxygen balance of an oxygen concentrator, characterized in that a control method for oxygen balance of an oxygen concentrator is used, comprising a consumption flow acquisition module, a detection module, an output flow acquisition module and a regulation module;

[0130] The consumption flow acquisition module is used to respectively acquire the flow of the oxygen inhalation port and the diffusion purification outlet, which are marked as the first flow and the second flow respectively;

[0131] The detection module is used to detect whether there is a change in the first flow rate, and if there is a change, obtain the change value;

[0132] Determine whether the change value is greater than a preset value, if so, update the first flow rate according to the change value, if less than, maintain the value of the first flow rate;

[0133] The output flow acquisition module is used to obtain the temperature and compressor parameters in the oxygen concentrator when the value of the first flow changes, and calculate the oxygen output flow through the temperature and compressor parameters, and call the adjustment module;

[0134] The regulating module is used to obtain the sum of the first flow rate and the second flow rate as the oxygen consumption flow rate; determine whether the oxygen consumption flow rate is greater than the oxygen output flow rate, if greater, obtain the flow difference between the two, and control the motor corresponding to the air duct valve of the diffusion purification outlet to operate according to the flow difference; if less than the oxygen output flow rate, maintain the opening and closing degree of the air duct of the diffusion purification outlet.

[0135] Preferably, the output flow acquisition module includes a standardization submodule, a temperature parameter acquisition submodule, an airflow parameter acquisition submodule and a calculation submodule;

[0136] The standardization submodule is used to obtain the standard oxygen output flow rate marked when the oxygen concentrator leaves the factory, which is marked as the third flow rate;

[0137] The temperature parameter acquisition submodule is used to determine whether the temperature is greater than a temperature threshold, and if so, to obtain a first parameter as a temperature adjustment parameter according to the temperature interval; if less than, to obtain a second parameter as a temperature adjustment parameter;

[0138] The airflow parameter acquisition submodule is used to acquire the exhaust mass flow of the first compression cylinder in the compressor, the intake mass flow of the adjacent compression cylinders, the exhaust mass flow, and the intake mass flow of the last compression cylinder;

[0139] Obtaining a first difference between the exhaust mass flow of adjacent compression cylinders and the intake mass flow of adjacent compression cylinders, if the first difference falls within the range threshold, obtaining a third parameter as the airflow adjustment parameter, if it does not fall within the range threshold, obtaining a second difference between the first difference and the edge value of the range threshold, obtaining the sum of the absolute values ​​of all the second differences as the second difference sum, and obtaining a fourth parameter as the airflow adjustment parameter according to the interval where the second difference sum is located;

[0140] The calculation submodule is used for obtaining the oxygen output flow rate by multiplying the airflow adjustment parameter and the temperature adjustment parameter by the third flow rate.

[0141] Preferably, the airflow parameter acquisition submodule includes a first unit, a second unit, a third unit and a fourth unit;

[0142] The first unit is used to obtain the inner diameter of the compression cylinder and the stroke of the piston, and obtain the theoretical working volume of the compression cylinder through the inner diameter and the piston;

[0143] The second unit is used to obtain the average intake pressure in the compression cylinder within one cycle based on the working cycle signal of the compression cylinder;

[0144] The third unit is used to obtain the volume V1 of the compression cylinder during air intake, obtain the final intake pressure P1 through the volume V1 and the temperature during air intake, and obtain the compression ratio based on the final intake pressure P1 and the average intake pressure;

[0145] The fourth unit is used to obtain the exhaust mass flow rate through the theoretical working volume and the compression ratio, and obtain the intake mass flow rate through the theoretical working volume and the exhaust mass flow rate;

[0146] Preferably, the regulating module includes an opening and closing degree acquisition submodule and a speed control submodule;

[0147] The opening and closing degree acquisition submodule is used to input the flow difference into the first neural network to obtain the opening and closing degree required for the air duct valve to reduce the flow difference;

[0148] The speed control submodule is used to input the opening and closing degree and the adjustment time into the PID controller to realize the control of the motor.

[0149] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0150] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for controlling oxygen balance of an oxygen concentrator, characterized in that: The steps include: Step S1: respectively obtaining the flow rates of the oxygen inlet and the diffusion purification outlet, and marking them as the first flow rate and the second flow rate respectively; Step S2: Detect whether there is a change in the first flow rate, and if there is a change, obtain a change value; Determine whether the change value is greater than a preset value, if so, update the first flow rate according to the change value, if less than, maintain the value of the first flow rate; Step S3: when the value of the first flow rate is updated, the temperature and compressor parameters in the oxygen concentrator are obtained, and the oxygen output flow rate is calculated according to the temperature and the compressor parameters, and step S4 is executed; Step S4: obtaining the sum of the first flow rate and the second flow rate as the oxygen consumption flow rate; Determine whether the oxygen consumption flow rate is greater than the oxygen output flow rate, if so, obtain the flow difference between the two, and control the motor corresponding to the air duct valve of the diffusion purification outlet to operate according to the flow difference; if less than the oxygen output flow rate, maintain the opening and closing degree of the air duct of the diffusion purification outlet; The steps of calculating the oxygen output flow rate in step S3 are as follows: obtaining the standard oxygen output flow rate marked when the oxygen concentrator leaves the factory, marked as the third flow rate; Determine whether the temperature is greater than a temperature threshold, if so, obtain a first parameter as a temperature adjustment parameter according to the temperature interval, and if less than a second parameter as a temperature adjustment parameter; Obtaining the exhaust mass flow rate of the first compression cylinder in the compressor, the intake mass flow rate of the adjacent compression cylinder, the exhaust mass flow rate, and the intake mass flow rate of the last compression cylinder; Obtaining a first difference between the exhaust mass flow of adjacent compression cylinders and the intake mass flow of adjacent compression cylinders, if the first difference falls within the range threshold, obtaining a third parameter as the airflow adjustment parameter, if it does not fall within the range threshold, obtaining a second difference between the first difference and the edge value of the range threshold, obtaining the sum of the absolute values ​​of all the second differences as the second difference sum, and obtaining a fourth parameter as the airflow adjustment parameter according to the interval where the second difference sum is located; The oxygen output flow rate is obtained by multiplying the airflow adjustment parameter and the temperature adjustment parameter by the third flow rate.

2. The method for controlling oxygen balance of an oxygen concentrator according to claim 1, characterized in that: The exhaust mass flow rate and intake mass flow rate are obtained as follows: The inner diameter of the compression cylinder and the stroke of the piston are obtained, and the theoretical working volume of the compression cylinder is obtained through the inner diameter and the piston, wherein the acquisition of the theoretical working volume is shown as follows: ； Where D is the cylinder diameter, S is the piston stroke, and V is the theoretical working volume; Based on the working cycle signal of the compression cylinder, the average intake pressure in the compression cylinder within one cycle is obtained; The volume V1 of the compression cylinder during air intake is obtained, the final intake pressure P1 is obtained through the volume V1 and the temperature during air intake, and the compression ratio is obtained based on the final intake pressure P1 and the average intake pressure; The formula for obtaining the intake end pressure P1 is as follows: ； Where n is the number of moles, R is the gas constant of air, T1 is the temperature at intake, and V1 is the volume of the compression cylinder at intake; The compression ratio r is obtained by the following formula: ； in is the average intake pressure, is the temperature variability index; The exhaust mass flow rate is obtained by the theoretical working volume and the compression ratio, and the intake mass flow rate is obtained by the theoretical working volume and the exhaust mass flow rate; The formulas for obtaining the exhaust mass flow rate and the intake mass flow rate are as follows: ； ； Where V is the theoretical working volume, is the exhaust mass flow rate, is the intake air mass flow rate.

3. The method for controlling oxygen balance of an oxygen concentrator according to claim 2, characterized in that: The steps of controlling the motor corresponding to the air duct valve of the diffusion purification outlet by the flow difference in step S4 are as follows: The flow difference is input into the first neural network to obtain the opening and closing degree required for the air duct valve to reduce the flow difference; The opening and closing degree and adjustment time are input into the PID controller to control the motor.

4. The method for controlling oxygen balance of an oxygen concentrator according to claim 3, characterized in that: The structure of the first neural network is as follows: The input layer of the first neural network takes the flow difference as input; The hidden layer is linearly transformed with the weight matrix W1 and the bias b1, and then the hidden layer output is obtained through the activation function f1; Finally, the output layer performs a linear transformation with the hidden layer output, weight matrix W2 and bias b2 to obtain the opening and closing degree; The specific hidden layer output H is as follows: ； The formula for obtaining the opening and closing degree is as follows: ； in , , are the proportional coefficients respectively, and H is the hidden layer output; In the PID controller, the formula for obtaining the motor speed is as follows: ； in For the required opening and closing degree, , , are the gains of the PID controller, To adjust the time, It is the accumulation of the opening and closing error values ​​of the air duct valve that did not reach the specified opening and closing degree after the motor speed was adjusted in the past.

5. A control system for oxygen balance of an oxygen concentrator, characterized in that: A method for controlling oxygen balance of an oxygen concentrator according to any one of claims 1 to 4, characterized in that it comprises a consumption flow acquisition module, a detection module, an output flow acquisition module and a regulation module; The consumption flow acquisition module is used to respectively acquire the flow of the oxygen inhalation port and the diffusion purification outlet, which are marked as the first flow and the second flow respectively; The detection module is used to detect whether there is a change in the first flow rate, and if there is a change, obtain the change value; Determine whether the change value is greater than a preset value, if so, update the first flow rate according to the change value, if less than, maintain the value of the first flow rate; The output flow acquisition module is used to obtain the temperature and compressor parameters in the oxygen concentrator when the value of the first flow changes, and calculate the oxygen output flow through the temperature and compressor parameters, and call the adjustment module; The regulating module is used to obtain the sum of the first flow rate and the second flow rate as the oxygen consumption flow rate; determine whether the oxygen consumption flow rate is greater than the oxygen output flow rate, if greater, obtain the flow difference between the two, and control the motor corresponding to the air duct valve of the diffusion purification outlet to operate according to the flow difference; if less than the oxygen output flow rate, maintain the opening and closing degree of the air duct of the diffusion purification outlet; The output flow acquisition module includes a standardization submodule, a temperature parameter acquisition submodule, an airflow parameter acquisition submodule and a calculation submodule; The standardization submodule is used to obtain the standard oxygen output flow rate marked when the oxygen concentrator leaves the factory, which is marked as the third flow rate; The temperature parameter acquisition submodule is used to determine whether the temperature is greater than a temperature threshold, and if so, to obtain a first parameter as a temperature adjustment parameter according to the temperature interval; if less than, to obtain a second parameter as a temperature adjustment parameter; The airflow parameter acquisition submodule is used to acquire the exhaust mass flow of the first compression cylinder in the compressor, the intake mass flow of the adjacent compression cylinders, the exhaust mass flow, and the intake mass flow of the last compression cylinder; Obtaining a first difference between the exhaust mass flow of adjacent compression cylinders and the intake mass flow of adjacent compression cylinders, if the first difference falls within the range threshold, obtaining a third parameter as the airflow adjustment parameter, if it does not fall within the range threshold, obtaining a second difference between the first difference and the edge value of the range threshold, obtaining the sum of the absolute values ​​of all the second differences as the second difference sum, and obtaining a fourth parameter as the airflow adjustment parameter according to the interval where the second difference sum is located; The calculation submodule is used for obtaining the oxygen output flow rate by multiplying the airflow adjustment parameter and the temperature adjustment parameter by the third flow rate.

6. The oxygen balance control system of an oxygen concentrator according to claim 5, characterized in that: The airflow parameter acquisition submodule includes a first unit, a second unit, a third unit and a fourth unit; The first unit is used to obtain the inner diameter of the compression cylinder and the stroke of the piston, and obtain the theoretical working volume of the compression cylinder through the inner diameter and the piston; The second unit is used to obtain the average intake pressure in the compression cylinder within one cycle based on the working cycle signal of the compression cylinder; The third unit is used to obtain the volume V1 of the compression cylinder during air intake, obtain the final intake pressure P1 through the volume V1 and the temperature during air intake, and obtain the compression ratio based on the final intake pressure P1 and the average intake pressure; The fourth unit is used to obtain the exhaust mass flow rate through the theoretical working volume and the compression ratio, and to obtain the intake mass flow rate through the theoretical working volume and the exhaust mass flow rate.

7. The oxygen balance control system of an oxygen concentrator according to claim 6, characterized in that: The regulating module includes an opening and closing degree acquisition submodule and a speed control submodule; The opening and closing degree acquisition submodule is used to input the flow difference into the first neural network to obtain the opening and closing degree required for the air duct valve to reduce the flow difference; The speed control submodule is used to input the opening and closing degree and the adjustment time into the PID controller to realize the control of the motor.

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