Nonlinear Control Method for Air Handling Unit

Abstract

The present invention relates to a non-linear control method for an air handling unit, which includes a duct system, a supply fan, a return fan, a cooling coil and a dehumidifying coil. The duct system includes a supply air duct and an exhaust air duct. The cooling water flow rate of the cooling coil is controlled by a control valve. The controller obtains monitoring signals through an outdoor temperature sensor, an outdoor humidity sensor, an indoor temperature sensor, an indoor humidity sensor, a supply air temperature sensor and a gas flow sensor, and performs calculations based on a non-linear control model. The air flow rate of the supply fan and the water flow rate of the control valve are controlled through control signals, so that the humidity and temperature in the room are equal to their respective expected values. The technical solution has high control accuracy and is more in line with the actual control situation.

Description

Technical Field

[0001] The present invention belongs to the technical field of indoor temperature and humidity control, and particularly relates to a non-linear control method for an air handling unit. Background Art

[0002] Indoor temperature and humidity are one of the key factors affecting the living environment. Human subjective reactions, sleep, emotions, and learning are all affected by the indoor environment. When the temperature and humidity exceed the range that the human body can bear, it will pose a great threat to people's physical and mental health. In addition, temperature and humidity are also the key factors for the smooth progress of many production activities. Therefore, the regulation of temperature and humidity has always been a hot issue in social production and life.

[0003] As the main means of controlling temperature and humidity, the control methods of air handling units mostly adopt model-free, linearization, and fuzzy control schemes, such as:

[0004] Literature [1]: PID-fuzzy control of air handling units in the presence of uncertainty;

[0005] Literature [2]: Nonlinear multivariable control and performance analysis of an air-handling unit;

[0006] Literature [3]: Fuzzy logic control of air-conditioning system in residential buildings”.

[0007] The existing technologies have the following defects:

[0008] In Literature [1], although the PID control method is simple, it is difficult to achieve precise control of temperature and humidity because it only considers the temperature and humidity errors.

[0009] In Literature [2], there is a model-based control method, which simplifies the non-linear model into a linear model and then designs a controller for the simplified linear model. Inevitably, some factors affecting temperature and humidity will be ignored during the model approximation process, resulting in a decrease in the final control accuracy.

[0010] For the fuzzy controllers in Literature [1] and [3], their computational complexity increases exponentially with the increase of fuzzy logic rules. Therefore, when there are many fuzzy rules, the computational complexity is likely to increase sharply. When there are few fuzzy rules, the approximation effect will also deteriorate.

[0011] References [1] and [2] consider the environmental temperature and humidity, humidity source intensity, and heat load as constant values. However, during the temperature and humidity control process of the air handling unit, these four factors change over time. For example, the outdoor environmental temperature is different at different times of the day, which causes the heat load value reflecting the degree of indoor and outdoor heat exchange to also change, etc. Therefore, ignoring the changes in these four factors will also have an adverse impact on the temperature and humidity control effect. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to make up for the deficiencies of the prior art and provide a non-linear control method for an air handling unit.

[0013] To solve the above technical problems, the technical solution of the present invention is as follows:

[0014] A non-linear control method for an air handling unit, including

[0015] A duct system, including a supply air duct and an exhaust air duct. The supply air duct serves as a passage for air to flow from the outside to the inside of the room, and the exhaust air duct serves as a passage for air to flow from the inside to the outside of the room;

[0016] A supply fan, connected to the indoor supply air outlet and the supply air duct, for delivering air to the room;

[0017] A return fan, connected to the indoor exhaust air outlet and the exhaust air duct, for exhausting the air in the room;

[0018] A cooling coil, arranged in the supply air duct, for cooling the air in the supply air duct. The liquid inlet of the cooling coil is connected to the liquid outlet of the cooling water source through a liquid inlet pipe and a control valve, and the control valve is used to control the flow rate of the cooling water; the liquid outlet of the cooling coil is connected to the return liquid port of the cooling water source through a return liquid pipe;

[0019] A dehumidification coil, arranged in the supply air duct and between the supply fan and the cooling coil, for reducing the moisture content in the air;

[0020] An outdoor temperature sensor and an outdoor humidity sensor are both arranged outdoors, respectively used for monitoring the temperature and humidity of the outdoor air;

[0021] An indoor temperature sensor and an indoor humidity sensor are both arranged indoors, respectively used for monitoring the temperature and humidity of the indoor air;

[0022] A supply air temperature sensor is arranged at the air outlet of the supply fan, for monitoring the temperature of the air at the air outlet of the supply fan;

[0023] A gas flow sensor is arranged at the indoor exhaust air outlet, for monitoring the gas flow rate;

[0024] The control system model in the controller is:

[0025]

[0026] Among them, 、 and are the outdoor humidity ratio, the supply air humidity ratio, and the indoor humidity ratio respectively, 、 and are the outdoor temperature, the supply air temperature, and the indoor temperature respectively, is the temperature gradient of the heat exchanger, is the humidity source intensity, is the heat load, and are the volume of the indoor space and the internal volume of the cooling coil respectively, and are the air flow rate of the supply fan and the cooling water flow rate of the control valve respectively, and are the specific heat of air and the specific heat of water respectively, and are the saturated water enthalpy and the evaporation enthalpy respectively, and are the air density and the water density respectively, , and are all system parameters, and their values are 0.25, 0.75, and 0.25 respectively;

[0027] Supply air humidity ratio 、Temperature gradient of the heat exchanger are both set values;

[0028] Humidity source intensity: Among them, is the gas flow rate;

[0029] Heat load: Among them, is the heat transfer coefficient, is the indoor surface area;

[0030] After the control model undergoes system transformation, the control model obtained is:

[0031]

[0032] Among them,

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] including the following steps:

[0039] S1: Set the desired humidity and desired temperature indoors through the data input module of the controller and desired temperature ;

[0040] S2: The outdoor temperature sensor, outdoor humidity sensor, supply air temperature sensor, indoor temperature sensor, indoor humidity sensor, and gas flow sensor all upload the monitoring signals to the controller;

[0041] S3: The controller calculates based on the monitoring signals uploaded in step S2 and the control model, controls the air flow of the supply fan through the control signal and controls the water flow of the control valve through the control signal ;

[0042] S4: Repeat steps S2 - S3, resulting in , .

[0043] Furthermore, the outdoor humidity satisfies:

[0044] and represents a known constant, represents an unknown bounded function;

[0045] The outdoor temperature satisfies:

[0046] and represents a known constant, represents an unknown bounded function;

[0047] The humidity source intensity satisfies:

[0048] and represents a known constant, is an unknown bounded function;

[0049] The heat load satisfies:

[0050] and represents a known constant, is an unknown bounded function.

[0051] Further, the controller includes a virtual control signal, an actual humidity control signal, and an actual temperature control signal.

[0052] The virtual control signal is:

[0053]

[0054] where 、 and represent positive constants, ;

[0055] The actual humidity control signal:

[0056]

[0057] where and are positive design parameters, ;

[0058] The actual temperature control signal is:

[0059]

[0060] where 、 、 、 and are positive constants, and the variables 、 and are:

[0061] 。

[0062] Further, ranges from 0.08 to 0.15, ranges from 0.45 to 1.2, ranges from 10 -30 to 1.5.

[0063] Further, is 0.1, is 0.6, is 0.1.

[0064] Further, ranges from 0.03 to 0.13, ranges from 0.02 to 0.35, ranges from 10 -30 to 0.5.

[0065] Further, takes a value of 0.1, takes a value of 0.3, takes a value of 0.1.

[0066] Further, the air supply duct and the exhaust duct of the pipeline system are connected by a regulating damper, and the regulating damper is used to adjust the ratio of fresh air to return air entering the air supply duct.

[0067] Further, the flow rate ratio of fresh air to return air is 1:3.

[0068] Further, it further includes a filter, which is arranged in the air supply duct and between the air inlet of the air supply duct and the cooling coil.

[0069] The beneficial effects that the present invention can achieve are:

[0070] (1) The control method proposed by the present invention can directly design a controller for the non-linear mathematical model of the air handling unit, avoiding the model simplification process and the problem of reduced control accuracy caused by the simplification.

[0071] (2) Since the present invention does not use the fuzzy logic systems in References [1] and [3], there is no problem of a sharp increase in the computational complexity of the controller caused by the increase of fuzzy rules.

[0072] (3) Considering the changes of environmental temperature and humidity, humidity source intensity and heat load with the control time, it is more in line with the actual control situation.

[0073] (4) Through the almost disturbance decoupling technology, the influence degree of the disturbance suffered by the system on its output can be attenuated to a given degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 is the schematic composition diagram of the air handling unit in the embodiment of the present invention;

[0075] Figure 2 is the schematic control diagram in the embodiment of the present invention;

[0076] Figure 3 is the indoor humidity error change curve of the air handling unit provided by the embodiment of the present invention.

[0077] Figure 4 is the indoor humidity change curve of the air handling unit provided by the embodiment of the present invention.

[0078] Figure 5 is the humidity control signal change curve of the air handling unit provided by the embodiment of the present invention.

[0079] Figure 6It is the indoor temperature error change curve provided by the embodiment of the present invention.

[0080] Figure 7 It is the indoor temperature change curve provided by the embodiment of the present invention.

[0081] Figure 8 It is the temperature control signal change curve of the air control processing unit provided by the embodiment of the present invention.

[0082] Figure 9 It is the supply air temperature change curve of the air control processing unit provided by the embodiment of the present invention.

[0083] Figure 10 It is the indoor humidity-temperature error change curve provided by the embodiment of the present invention (with a decreasing and ).

[0084] Figure 11 It is the humidity-temperature control signal change curve of the air control processing unit provided by the embodiment of the present invention (with a decreasing and ).

[0085] Figure 12 It is the indoor humidity-temperature error change curve provided by the embodiment of the present invention (with an increasing and a decreasing ).

[0086] Figure 13 It is the humidity-temperature control signal change curve of the air control processing unit provided by the embodiment of the present invention (with an increasing and a decreasing ).

[0087] Figure 14 It is the indoor humidity-temperature error change curve provided by the embodiment of the present invention (with a decreasing and an increasing ).

[0088] Figure 15 It is the humidity-temperature control signal change curve of the air control processing unit provided by the embodiment of the present invention (with a decreasing and an increasing ).

[0089] Figure 16 It is the indoor humidity-temperature error change curve provided by the embodiment of the present invention (with a constant and ).

[0090] Figure 17is the wet and temperature control signal change curve provided by the embodiment of the present invention (with a constant and ).

[0091] In the figure: 1 - room, 2 - supply fan, 3 - dehumidifying coil, 4 - cooling coil, 5 - control valve, 6 - filter, 7 - return liquid pipe, 8 - inlet liquid pipe, 9 - regulating damper, 10 - return fan. Detailed implementation manners

[0092] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0093] The internal space of room 1 is called "indoor", and the external space of room 1 is called "outdoor".

[0094] The "air handling unit" described in the present invention is essentially considered to operate in summer.

[0095] As Figure 1 shown, the air handling unit includes:

[0096] A duct system, including a supply duct and an exhaust duct. The supply duct serves as a passage for air to flow from the outdoor to the indoor, and the exhaust duct serves as a passage for air to flow from the indoor to the outdoor; the supply duct and the exhaust duct are connected by a regulating damper 9, and the regulating damper 9 is used to adjust the ratio of fresh air to return air entering the supply duct. In this embodiment, the flow ratio of fresh air to return air is 1:3;

[0097] A supply fan 2, connected to the indoor supply air outlet and the supply duct, for delivering air to the indoor;

[0098] A return fan 10, connected to the indoor exhaust air outlet and the exhaust duct, for exhausting the air in the indoor;

[0099] A cooling coil 4, arranged in the supply duct, for cooling the air in the supply duct. The liquid inlet of the cooling coil 4 is connected to the liquid outlet of the cooling water source through an inlet liquid pipe 8 and a control valve 5, and the control valve 5 is used to control the flow rate of the cooling water; the liquid outlet of the cooling coil 4 is connected to the return liquid port of the cooling water source through a return liquid pipe 7;

[0100] A dehumidifying coil 3, arranged in the supply duct and between the supply fan 2 and the cooling coil 4, for reducing the moisture content in the air;

[0101] It further includes a filter 6, arranged in the supply duct and between the air inlet of the supply duct and the cooling coil 4.

[0102] As Figure 2As shown, the outdoor temperature sensor and the outdoor humidity sensor are both set outdoors and are respectively used to monitor the temperature and humidity of the outdoor air; the indoor temperature sensor and the indoor humidity sensor are both set indoors and are respectively used to monitor the temperature and humidity of the indoor air; the supply air temperature sensor is set at the air outlet of the supply fan 2 and is used to monitor the temperature of the air at the air outlet of the supply fan 2; the gas flow sensor is set at the indoor air outlet of the return fan 10 (it can also be set at the air inlet of the regulating damper 9) and is used to monitor the gas flow rate.

[0103] A non-linear control method for an air handling unit includes the following steps:

[0104] S1: Set the desired humidity and the desired temperature in the room through the data input module of the controller;

[0105] S2: The outdoor temperature sensor, the outdoor humidity sensor, the supply air temperature sensor, the indoor temperature sensor, the indoor humidity sensor and the gas flow sensor all upload the monitoring signals to the controller;

[0106] S3: The controller calculates based on the monitoring signals uploaded in step S2 and the control model, and controls the air flow rate of the supply fan 2 through the control signal and controls the water flow rate of the control valve 5 through the control signal ;

[0107] S4: Repeat steps S2 - S3 until, , .

[0108] 1) In the air handling unit, the control system model in the controller is:

[0109] (Ⅰ)

[0110] Among them, , and are the outdoor humidity ratio, the supply air humidity ratio and the indoor humidity ratio respectively, , and are the outdoor temperature, the supply air temperature and the indoor temperature respectively, is the temperature gradient of the heat exchanger, is the humidity source intensity, is the heat load, and are the volume of the indoor space and the internal volume of the cooling coil 4 respectively, and are the air flow rate of the supply fan 2 and the cooling water flow rate of the control valve 5 respectively, and Specific heat of air and specific heat of water respectively. and Enthalpy of saturated water and evaporation enthalpy respectively. and Density of air and density of water respectively. , and are all system parameters, and their values are 0.25, 0.75, and 0.25 respectively;

[0111] Humidity ratio of the supply air , temperature gradient of the heat exchanger are all set values;

[0112] Humidity source intensity: , where is the gas flow rate, measured by a gas flow sensor;

[0113] Heat load: , where is the heat transfer coefficient, is the indoor surface area;

[0114] 2) After the control model undergoes system transformation, the control model obtained is:

[0115] (Ⅱ)

[0116] Among them,

[0117]

[0118] (Ⅲ)

[0119]

[0120]

[0121] (Ⅳ)

[0122] Among them represents the system state variable, ; and represent the control signals of humidity and temperature and the system outputs of humidity and temperature respectively, .

[0123] Among them and satisfy:

[0124] (Ⅴ)

[0125] And and represent known constants, and represent unknown bounded functions.

[0126] Remark 1: Humidity and temperature cannot remain constant throughout the day. Over a period of time, they can be considered to vary around two values respectively. Given that the ambient humidity and temperature are bounded, their variations are also bounded. Therefore, (V) holds.

[0127] where and satisfy:

[0128] (VI)

[0129] and and are both known constants. and are unknown bounded functions.

[0130] Remark 2: As the ambient temperature and humidity change, the exchange of temperature and humidity between indoors and outdoors at different times is different. Therefore, the corresponding wet source intensity and heat load also vary with time. Similar to Remark 1, they can also be considered to vary around two values. At the same time, regardless of how the temperature and humidity change, the differences in temperature and humidity between indoors and outdoors are always bounded, making and bounded. Therefore, and are bounded. That is, (VI) is reasonable.

[0131] 3) Define the following transformation formula

[0132] (VII)

[0133] where and represent the desired humidity and temperature; is a virtual control signal, which will be designed later.

[0134] 4) Construct the first Lyapunov function as follows:

[0135] (VIII)

[0136] can be written as:

[0137] (IX)

[0138] According to Young's inequality, we can obtain:

[0139] (X)

[0140] Wherein are design parameters.

[0141] Substitute equation (X) into to obtain:[[]]

[0142] (XI)

[0143] The humidity control signal is:[[]]

[0144] (XII)

[0145] Wherein are positive design parameters.

[0146] Remark 3: In equation (XII), the system parameter is a positive constant. According to the model, it can be known that is non-zero. Therefore,[[]] is not equal to zero.

[0147] Using , equation (XI) can be rewritten as:[[]]

[0148] (XIII)

[0149] 5) The second Lyapunov function is shown as follows:[[]]

[0150] (XIV)

[0151] By differentiating equation (XIV) and using equation (XIII), it satisfies:[[]]

[0152] (XV)

[0153] According to Young's inequality, it can be obtained that:[[]]

[0154] (XVI)

[0155] Wherein and represent positive constants.

[0156] Substitute equation (XVI) into equation (XV) to generate:[[]]

[0157] (XVII)

[0158] The virtual control signal is:[[]]

[0159] (XVIII)

[0160] Wherein is a constant.

[0161] Remark 4: Since there is always humidity exchange between indoors and outdoors, a part of is needed to offset this exchange effect, so that the value of is always non-zero. Therefore, the denominator of is non-zero.

[0162] Substitute into Equation (XVII), we can get:

[0163] (XIX)

[0164] 6) The third Lyapunov function is as follows:

[0165] (XX)

[0166] Using Equation (XIX), is:

[0167] (XXI)

[0168] can be written as:

[0169] (XXII)

[0170] Using Equation (II) and Equation (VI), we can get:

[0171] (XXIII) To simplify the expression, define variables , and as:

[0172] (XXIV)

[0173] Then is simplified to:

[0174] (XXV)

[0175] Using Equation (V) and Equation (XXV), is transformed into:

[0176] (XXVI)

[0177] Using Young's inequality, we have:

[0178] (XXVII)

[0179] Wherein 、 、 and are positive constants.

[0180] Substituting (XXVII) into (XXVI) gives:

[0181] (XXVIII)

[0182] The temperature control signal is:

[0183] (XXIX)

[0184] Wherein represents a design parameter.

[0185] Using , finally satisfies:

[0186] (XXX)

[0187] When is the case of the first lemma, we can obtain:

[0188] (XXXI)

[0189] Using the Lyapunov stability theory, it can be guaranteed that , that is , .

[0190] When , integrating Equation (XXX) with respect to time and combining Lemma 1, we get:

[0191] (XXXII)

[0192] Considering , we get:

[0193] (XXXIII)

[0194] Wherein .

[0195] Using Equation (VII), we can obtain:

[0196] (XXXIV)

[0197] Wherein .

[0198] Define the vector as:

[0199] (XXXV)

[0200] Finally, substituting Equation (XXXV) into Equation (XXXIV) gives the second case in Lemma 1, that is, the influence of the perturbation on the system output decays to a given degree . Therefore, by designing the control signals in Equations (XII) and (XXIX), the problem of almost disturbance decoupling for Equation (II) is solved.

[0201] Lemma 1:

[0202] Almost disturbance decoupling: The column vector represents the disturbance. The column vectors and are the system output and the target output respectively. The goal is to achieve tracking of by designing a smooth state feedback control signal, so that the closed-loop system (II) satisfies the following conditions.

[0203] (1) When the disturbance , combining with the Lyapunov stability theory, there is established.

[0204] (2) When the disturbance , and , for the case where the initial value is 0, the system satisfies:

[0205]

[0206] where represents a positive constant.

[0207] 7) Simulation verification

[0208] To verify the effectiveness of the control method proposed in the present invention, Matlab is used for simulation. The developed control scheme (denoted as C) is compared with the corresponding linearized control scheme (denoted as L) and the PID control scheme (denoted as P), and the effectiveness and superiority of C are verified.

[0209] During working hours, there are more people in the office (i.e., Room 1), so the ideal indoor humidity and temperature are slightly lower; during break hours, there are fewer people in the office, so the ideal indoor humidity and temperature are slightly higher. Therefore, the desired humidity curve varies around (simplified to ) and respectively, and the desired temperature curve varies around 25°C and 26°C.

[0210] (A) and the rising situation

[0211] The initial value is . The control signals are (ⅩⅡ), (ⅩⅧ) and (ⅩⅩⅨ), and their parameter values are .

[0212] The simulation results are as Figures 3 - 9 shown Figure 3 and give the humidity error. It can be clearly seen that C is the most stable with the smallest variation range. For C, L, and P (the absolute average value and root mean square value of the error are described in this order), their absolute average values are respectively and , and the root mean square value is and .

[0213] The "absolute average value" of the error represents the level of the average error. The smaller the "absolute average value" of the error, the smaller the average error, indicating that the overall tracking control effect of the controller is better.

[0214] The "root mean square value" of the error represents the fluctuation level of the error. The smaller the "root mean square value" of the error, the smaller the amplitude of the error fluctuation, indicating that the overall tracking control effect of the controller is more stable.

[0215] The humidity curve is as Figure 4 shown. Although the tracking performance of C is not the best in the initial stage, its error is very small and completely acceptable. And in all subsequent times, the performance of C is the best. The humidity control signal is as Figure 5 shown. The stable values of the three are basically the same, which once again proves that C is the best. It should be noted that the of C is not zero, which meets the requirements of Note 4 (this is also guaranteed in the following example). From Figure 6 , it can be seen that except for C, the temperature errors are all fluctuating. Their absolute average values are and , and the root mean square values are and . In Figure 7 , whether in the stable state or in the changing state, C can track the target temperature most accurately, and P completely fails in the initial stage. The temperature control signal is as Figure 8 shown. P increases or decreases sharply in the starting period, L has been oscillating, and only C maintains a more reasonable amplitude and frequency. The supply air temperature is asFigure 9 As shown, it varies within a reasonable range.

[0216] (B) and the case of decline

[0217] The values of some parameters are

[0218] . The values of other parameters are the same as those in (A).

[0219] The simulation results are as Figures 10 - 11 shown. In Figure 10 the humidity and temperature errors are given. The humidity-temperature error of C is undoubtedly the most stable. For the humidity error, their absolute average values are respectively and , and the root mean square value is and . For the temperature error, their absolute average values are respectively and , and the root mean square value is and . The humidity and temperature control signals are as Figure 11 shown. They are bounded and have similar steady-state values, which means that the required energy is similar.

[0220] (C) rise and the case of decline

[0221] The values of some parameters are

[0222] The values of the remaining parameters are the same as those in (A).

[0223] The simulation results are as Figures 12 - 13 shown. It can be seen from Figure 12 that C has obvious advantages in terms of temperature and humidity errors. For the humidity error, their absolute average values are respectively and , and the root mean square value is and . For the temperature error, their absolute average values are respectively and , and the root mean square value is and . The actual control laws and are as Figure 13 shown. During the entire operation, the three Stable change, only that of C Changes with the best amplitude among the three, and the three and respectively have approximately the same steady-state energy, indicating that C is better.

[0224] (D) Descent and Ascent situations

[0225] Some parameter values are

[0226] . The values of the remaining parameters are the same as those in (A).

[0227] The comparison results are as Figures 14 - 15 shown. The error changes are as Figure 14 shown, where the fluctuations of L and P are relatively large. For humidity error, their absolute average values are respectively and , and the root mean square values are and . For temperature error, their absolute average values are respectively and , and the root mean square values are and . and As Figure 15 shown, the superiority of C can be easily seen.

[0228] (E) and Constant situations

[0229] The initial values are ,

[0230] ,

[0231] . The values of other parameters are the same as those in (A).

[0232] The simulation results are as Figures 16 - 17 shown, and the errors are as Figure 16 shown. The two errors of C are relatively stable. In terms of humidity error, C and L have the fastest convergence rate, and P almost fluctuates all the time. Compared with L, C has no overshoot. Their absolute average values are respectively and , and the root mean square values are and 。For the temperature error, C converges to zero in only about 20 seconds. Their absolute average values are respectively and , and the root mean square values are and . Figure 17 Two control signals are given. Both of these control signals have bounded variations and each has approximately the same steady-state energy, thus highlighting the advantage of C.

[0233] The following table is the table of physical meanings and values of the hot fluid parameters of the air handling unit in this embodiment

[0234]

[0235] The above is only one implementation manner of the present invention. The protection scope of the present invention is not limited to the above embodiments. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and refinements made without departing from the idea of the present invention are within the protection scope of the present invention.

Claims

1. A non-linear control method for an air handling unit, characterized in that: including a pipe system including a supply air duct and an exhaust air duct, the supply air duct serving as a passage for air to flow from the outside to the inside of the room, and the exhaust air duct serving as a passage for air to flow from the inside to the outside of the room; a supply air fan (2) connected to an indoor supply air outlet and the supply air duct for supplying air to the room; a return air fan (10) connected to an indoor exhaust air outlet and the exhaust air duct for exhausting the air in the room; a cooling coil (4) disposed in the supply air duct for cooling the air in the supply air duct, the liquid inlet of the cooling coil (4) being connected to the liquid outlet of a cooling water source through a liquid inlet pipe (8) and a control valve (5), the control valve (5) being used to control the flow rate of the cooling water; the liquid outlet of the cooling coil (4) is connected to the return liquid port of the cooling water source through a return liquid pipe (7); a dehumidifying coil (3) disposed in the supply air duct and between the supply air fan (2) and the cooling coil (4) for adjusting the moisture content in the air; an outdoor temperature sensor and an outdoor humidity sensor are both disposed outdoors and are respectively used for monitoring the temperature and humidity of the outdoor air; an indoor temperature sensor and an indoor humidity sensor are both disposed indoors and are respectively used for monitoring the temperature and humidity of the indoor air; a supply air temperature sensor is disposed at the air outlet of the supply air fan (2) for monitoring the temperature of the air at the air outlet of the supply air fan (2); a gas flow sensor is disposed at the indoor exhaust air outlet for monitoring the gas flow rate; the control system model in the controller is: （Ⅰ） wherein, , and are the outdoor humidity ratio, the supply air humidity ratio, and the indoor humidity ratio respectively, , and are the outdoor temperature, the supply air temperature, and the indoor temperature respectively, is the temperature gradient of the heat exchanger, is the humidity source intensity, is the heat load, and are the volume of the indoor space and the internal volume of the cooling coil (4) respectively, and are the air flow rate of the supply fan (2) and the cooling water flow rate of the control valve (5) respectively, and are the specific heat of air and the specific heat of water respectively; and are the saturated water enthalpy and the evaporation enthalpy respectively, and are the air density and the water density respectively, , and are both system parameters, and their values are 0.25, 0.75 and 0.25 respectively; Supply air humidity ratio and the temperature gradient of the heat exchanger are both set values; Humidity source intensity: , where is the gas flow rate; Heat load: , where is the heat transfer coefficient, is the indoor surface area; After the control model is transformed by the system transformation, the control model is obtained: （Ⅱ） Among them, （Ⅲ） （Ⅳ） Among them, represents the system state variable, ; is the humidity control signal, is the temperature control signal, is the system output of humidity, is the system output of temperature; and satisfy: （Ⅴ） , , and are all known constants, and are all unknown bounded functions; and satisfy: （Ⅵ） And and are both known constants; and are both unknown bounded functions; Define the following transformation formula: （Ⅶ） Among them and represent the desired humidity and temperature; is a virtual control signal, which will be designed subsequently; Construct the first Lyapunov function as follows: （Ⅷ） It can be written as: （Ⅸ） According to Young's inequality, it can be obtained that: （Ⅹ） wherein are design parameters; Substitute formula (Ⅹ) into to obtain: （ⅩⅠ） Humidity control signal is as follows: （ⅩⅡ） wherein is a positive design parameter; Using , Equation (ⅩⅠ) can be rewritten as: （ⅩⅢ） Construct the second Lyapunov function as follows: （ⅩⅣ） By differentiating Equation (XIV) and using Equation (XIII), It satisfies: （ⅩⅤ） According to Young's inequality, it can be obtained that: （ⅩⅥ） wherein and both represent positive constants; Substitute equation (ⅩⅥ) into equation (ⅩⅤ) to generate: （ⅩⅦ） Virtual control signal is as follows: （ⅩⅧ） wherein is a constant; Substitute into formula (XVII), and we can get: （ⅩⅨ） Construct the third Lyapunov function as follows: （ⅩⅩ） Using formula (XIX), it is: （ⅩⅩⅠ） It can be written as: （ⅩⅩⅡ） Using equation (Ⅱ) and equation (Ⅵ), it can be obtained that: （ⅩⅩⅢ） To simplify the expression, define the variables , and as follows: （ⅩⅩⅣ） Then is reduced to: （ⅩⅩⅤ） Using formula (V) and formula (XXV), It is transformed into: （ⅩⅩⅥ） Using Young's inequality, there is: （ⅩⅩⅦ） Among them , , and are all positive constants; Substitute (ⅩⅩⅦ) into (ⅩⅩⅥ) to get: （ⅩⅩⅧ） Temperature control signal is as follows: （ⅩⅩⅨ） wherein represents a design parameter; Through the almost disturbance decoupling technology, the influence degree of the disturbance suffered by the system on its output is attenuated to a given degree; including the following steps: S1: Set the desired humidity and desired temperature indoors through the data input module of the controller and desired temperature ; S2: The outdoor temperature sensor, the outdoor humidity sensor, the supply air temperature sensor, the indoor temperature sensor, the indoor humidity sensor, and the gas flow sensor all upload the monitoring signals to the controller; S3: The controller calculates based on the monitoring signals uploaded in step S2 and the control model, and controls the air flow rate of the air blower (2) through a control signal and controls the water flow rate of the control valve (5) through a control signal ; S4: Repeat steps S2 - S3, resulting in, , .

2. The non-linear control method of the air handling unit according to claim 1, characterized in that: The value range of is 0.45 - 1.2, The value range of -30 is 10 ~1.

5.

3. The non-linear control method for an air handling unit according to claim 2, wherein: takes the value of 0.1, takes the value of 0.6, takes the value of 0.

1.

4. The non-linear control method of the air handling unit according to claim 1, characterized in that: The value range of is 0.02 to 0.35, The value range of -30 is 10 ~0.

5.

5. The non-linear control method of the air handling unit according to claim 4, characterized in that: The value of is 0.1, The value of is 0.3, The value of is 0.

1.

6. The non-linear control method of the air handling unit according to claim 1, characterized in that: The supply air duct and the exhaust air duct of the pipe system are connected through an adjusting damper (9), and the adjusting damper (9) is used to adjust the ratio of fresh air to return air entering the supply air duct.

7. The non-linear control method of the air handling unit according to claim 6, characterized in that: The flow ratio of fresh air to return air is 1:

3.

8. The non-linear control method for an air handling unit according to claim 1, characterized in that: It further includes a filter (6) disposed in the supply air duct and between the air inlet of the supply air duct and the cooling coil (4).

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