A fresh air system and a control method thereof

Abstract

The application provides a control method of a fresh air system, wherein an indoor air supply unit comprises a direct current motor, and the method comprises the following steps: an detecting unit detects indoor air quality every other period, and obtains a detection value; a control unit compares the detection value with a preset value, and calculates a first difference value between the detection value and the preset value; when the first difference value is greater than a set value, the indoor air supply unit is started; after the indoor air supply unit is started, the control unit calculates a second difference value between the first difference value obtained in a current period and the first difference value obtained in a previous period, and adjusts a fresh air introduction amount of the indoor air supply unit according to the second difference value. The application further provides a fresh air system. The application has the advantages that the excellent speed regulation performance of the direct current motor is utilized, the fresh air system air volume is accurately regulated and controlled, and thus the energy saving property of the fresh air system is greatly improved under the premise of ensuring user comfort.

Description

Technical Field

[0001] This invention relates to the field of fresh air system technology, and in particular to a fresh air system and its control method. Background Technology

[0002] Compared to the internal air circulation method used by air conditioners, the fresh air system operates on a more health-friendly displacement method. It can draw fresh outdoor air into the room, filter and remove dust from the air entering the room, and at the same time exhaust the indoor stale air to the outside, keeping the indoor environment comfortable and unobstructed.

[0003] However, existing fresh air systems have relatively simple control modes and cannot adapt to changes in the indoor environment in a timely manner, which greatly increases the user's operating costs. According to feedback on the use of existing fresh air systems, more than half of the users rarely use fresh air systems on a daily basis due to their high energy consumption and operating costs, and instead prefer to use traditional methods such as opening doors and windows for ventilation. Summary of the Invention

[0004] The purpose of this invention is to provide a control method for a fresh air system, which adjusts the fresh air intake of the indoor air supply unit in real time according to a second difference, thereby ensuring both the good comfort of the fresh air system and improving its energy efficiency.

[0005] This invention provides a control method for a fresh air system. The fresh air system includes a detection unit, a control unit, and an indoor air supply unit. The indoor air supply unit of the fresh air system includes a DC motor. The method includes the following steps: the detection unit detects the indoor air quality every cycle S and obtains a detection value Z. m m is a positive integer; the control unit will detect the value Z. m The detection value Z is calculated by comparing it with the preset value Z0. m The first difference e between the preset value Z0 and the preset value Z0 m When the first difference e m When the value is greater than the set value L, the indoor air supply unit is activated; after the indoor air supply unit is activated, the control unit calculates the first difference e obtained in the current cycle. m The first difference e obtained from the previous cycle m-1 The second difference f between m And based on the second difference f m Adjust the fresh air intake of the indoor air supply unit. This invention is based on a first difference e. m To control the opening of the indoor air supply unit, and after the indoor air supply unit is opened, based on the second difference f mThe fresh air intake can be directly adjusted by the indoor air supply unit. Therefore, during the operation of the fresh air system, it is not necessary to compare the detection values ​​obtained in all cycles with the preset values ​​to obtain the corresponding fresh air intake. The algorithm is simple, clear, and easy to control, avoiding frequent start-up and shutdown of the fresh air device.

[0006] Preferably, the indoor air supply unit has multiple air supply levels; the higher the air supply level, the greater the amount of fresh air introduced. The control unit determines the amount of fresh air based on the second difference f. m Switching the air supply level of the indoor air supply unit. This invention relies on a steplessly speed-regulating DC motor to achieve multiple air supply levels, facilitating more precise adjustment of the fresh air intake of the indoor air supply unit, thereby improving user comfort and the energy efficiency of the fresh air system.

[0007] Preferably, when the second difference f m When the value is greater than 0, the control unit increases the air supply speed of the indoor air supply unit; when the second difference f m When the value equals 0, the control unit maintains the air supply level of the indoor air supply unit unchanged; when the second difference f m When the value is less than 0, the control unit reduces the air supply level of the indoor air supply unit. This invention can be based on the second difference f. m The air supply level can be directly adjusted; the control logic is simple and easy to set.

[0008] Preferably, the control unit determines the value based on the second difference f. m Calculate the fresh air increment and adjust the fresh air intake of the indoor air supply unit accordingly; the formula for calculating the fresh air increment ΔFan is: ΔFan=n*f m Where the correction value n>0. By introducing an incremental fresh air intake, the amount of fresh air introduced is adjusted, resulting in higher precision, a more intelligent and efficient adjustment process, and reduced user operating costs.

[0009] Preferably, the control unit adjusts the correction amount based on the detected value, the first difference, and the second difference, and calculates the fresh air increment ΔFan based on the first difference, the second difference, and the adjusted correction amount. Then, it adjusts the fresh air intake of the indoor air supply unit according to the fresh air increment ΔFan. Using a fuzzy controller to adjust the fresh air intake allows for more precise control of the fresh air intake, resulting in better indoor comfort, more energy-efficient operation of the fresh air system, and reduced user operating costs.

[0010] Preferably, the first difference, the second difference, and the adjusted correction amount are substituted into the PID algorithm formula, which is: ΔFan=kp×n×f m +ki×(S / 2×Si)×(e m +e m-1 )+kd×(S / 2×Si)×f mWhere S is the period, Si is the given parameter value, and kp, n, ki, and kd are correction values.

[0011] Preferably, the correction amount n is the first difference e obtained with respect to the current period. m The variable, when e m When ≤L, n=0; when L<e m When n ≤ 0, n and e m Positive correlation; when e m When the value is greater than 0, n = X; where the set value L < 0 and the set value X > 0.

[0012] Preferably, if the first difference obtained within the first set time period is less than the set value L, the indoor air supply unit is turned off. This setting can effectively reduce the phenomenon of repeated opening and closing of the indoor air supply unit caused by the small fluctuations of the detected value around the set value, thereby improving user comfort and extending the service life of the fresh air system.

[0013] Preferably, the method further includes the step of: after the detection unit has been running continuously for a second set time period, the control unit predicts the detection value that the detection unit can obtain after running continuously for a third set time period based on the detection value obtained by the detection unit during the second set time period, thereby obtaining a predicted detection result value, and then calculates a fourth difference between the predicted detection result value and the detection value obtained in the current cycle. With the assistance of the predicted detection result value, the airflow adjustment of the fresh air system is more intelligent, and the user experience is better.

[0014] Preferably, when the fourth difference is greater than 0, the control unit increases the fresh air intake of the indoor air supply unit. This setting can increase the fresh air intake in advance during the third set time period, preventing the air quality from continuously declining during the third set time period and helping to improve indoor comfort.

[0015] Preferably, when the detection unit experiences a communication malfunction, the control unit maintains a constant fresh air intake from the indoor air supply unit for a fourth predetermined time period, and then shuts down the indoor air supply unit. This design improves the user experience while reducing the energy consumption of the fresh air system and lowering user operating costs.

[0016] Preferably, the detection unit includes one or more of the following: a CO2 sensor, a particulate matter sensor, a formaldehyde sensor, a TVOC sensor, a temperature sensor, and a humidity sensor. The detection unit can achieve comprehensive monitoring of indoor air quality and improve the accuracy of airflow regulation in the fresh air system.

[0017] Preferably, the fresh air system further includes an air conditioning unit, and the control unit adjusts the supply air temperature of the indoor air supply unit according to the set temperature T of the air conditioning unit. Adjusting the supply air temperature of the fresh air introduced by the fresh air unit according to the set temperature of the air conditioning unit enables coordinated control of the air conditioning unit and the fresh air unit. This allows the supply air temperature to better meet the system performance requirements, satisfying user comfort while achieving energy savings and reducing user operating costs.

[0018] Preferably, the detection unit includes an indoor temperature sensor and an outdoor temperature sensor. The indoor temperature sensor detects the indoor temperature T1, and the outdoor temperature sensor detects the outdoor temperature T2. The control unit adjusts the operation of the fresh air device based on the difference between the indoor temperature T1 and the outdoor temperature T2, and the set temperature T. Adjusting the operation of the fresh air device according to the indoor-outdoor temperature difference allows for precise control of the introduced fresh air temperature, resulting in high accuracy, better meeting user comfort requirements, and high energy efficiency.

[0019] Preferably, the fresh air device further includes a fresh air heat exchange unit and an electric valve connected to the fresh air heat exchange unit. When |T1-T2| ≤ the set value T0, the electric valve is closed; when |T1-T2| > the set value T0, the control unit opens the electric valve. This setting provides high control precision, better meets user comfort requirements, and is highly energy-efficient.

[0020] Preferably, the fresh air system further includes a compressor, and the control unit adjusts the operating frequency of the compressor based on the difference between the indoor temperature T1 and the outdoor temperature T2 and the set temperature T. This setting provides high control precision, better meets user comfort requirements, and is highly energy-efficient.

[0021] Preferably, the fresh air system includes multiple air conditioning units, each with a set temperature. The control unit adjusts the supply air temperature of the indoor air supply unit based on the average of the multiple set temperatures. Adjusting the supply air temperature based on the average of the set temperatures T of the multiple air conditioning units allows the supply air temperature to be closer to the indoor temperature of the area where the multiple air conditioning units are located, achieving energy savings while meeting user comfort requirements and reducing user operating costs.

[0022] The present invention also provides a fresh air system, which is controlled by the aforementioned control method.

[0023] The advantage of this invention is that it uses a DC motor and takes advantage of the excellent speed regulation performance of the DC motor to provide a fresh air system air volume control method that changes the fresh air intake with the second difference. This achieves precise control of the fresh air system air volume, greatly improves the energy efficiency of the fresh air system and reduces energy consumption while ensuring user comfort and health. It also avoids the increase in operating costs caused by a single control mode, thereby encouraging users to use the fresh air system and reducing the abandonment of the purchased fresh air system. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the air volume control process of a fresh air system provided by a technical solution of the present invention;

[0025] Figure 2 This is a schematic diagram of the air volume control process of a fresh air system provided by another technical solution of the present invention;

[0026] Figure 3 The correction amount n in Example 1 / 2 is related to the first difference e. m A schematic diagram of the function;

[0027] Figure 4 In Example 2, the correction amount kp is related to the second difference f. m A schematic diagram of the function;

[0028] Figure 5 In Example 2, the correction value ki is related to the detection value Z. m A schematic diagram of the function;

[0029] Figure 6 In Example 2, the correction amount kd is related to the third difference g. m A schematic diagram of the function;

[0030] Figure 7 This is a schematic diagram of the fresh air system of the present invention. Detailed Implementation

[0031] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0032] <Fresh Air System>

[0033] like Figure 7As shown, this invention provides a fresh air system, including an air conditioning unit and a fresh air unit. The air conditioning unit includes an outdoor unit and an indoor unit, each equipped with a heat exchange unit (i.e., the outdoor unit has an outdoor heat exchange unit, and the indoor unit has an indoor heat exchange unit). They are connected by refrigerant piping to form a refrigerant circuit, which includes a compressor and an electric valve. The compressor regulates the refrigerant circulation in the circuit, and the electric valve regulates the refrigerant flow through the heat exchanger. Fans are also installed in both the outdoor and indoor units to regulate the airflow through the heat exchanger. By adjusting the operating state of the air conditioning unit, the heat exchange capacity of the heat exchanger can be adjusted. Specifically, the heat exchange capacity can be adjusted using one or more of the following three methods: 1) changing the compressor frequency to regulate the refrigerant circulation in the circuit; 2) adjusting the electric valve opening to regulate the refrigerant flow through the heat exchanger; 3) adjusting the fan speed to regulate the airflow through the heat exchanger. An air conditioning unit can consist of one outdoor unit connected to one or more indoor units, or multiple outdoor units connected to multiple indoor units. Each indoor unit is also equipped with a control terminal, which can be one or more of a wired remote control, a wireless remote control, or a mobile terminal. The indoor unit receives user commands through the control terminal and then controls the operation of the air conditioning unit according to the user commands.

[0034] The fresh air system includes an indoor unit and an outdoor unit, each equipped with a heat exchange unit (i.e., the outdoor unit has an outdoor heat exchange unit, and the indoor unit has a fresh air heat exchange unit). They are connected via refrigerant piping to form a refrigerant circuit, which includes a compressor and an electric valve. The compressor regulates the refrigerant circulation volume in the circuit, while the electric valve regulates the refrigerant flow through the fresh air heat exchange unit. The indoor unit's air supply unit regulates the amount of fresh air introduced. This fresh air can be directly supplied to the room or its temperature can be regulated by the heat exchange unit before being introduced. By adjusting the operating status of the fresh air system, the heat exchange capacity of the heat exchange unit can be adjusted, thereby regulating the temperature of the fresh air flowing through it. Specifically, the heat exchange capacity of the fresh air heat exchange unit can be adjusted through one or more of the following three methods: 1) changing the compressor frequency to adjust the refrigerant circulation volume in the refrigerant circuit; 2) adjusting the opening of the electric valve to adjust the refrigerant flow rate through the fresh air heat exchange unit; 3) adjusting the fan speed of the indoor air supply unit to adjust the air flow rate through the fresh air heat exchange unit. The fresh air system can consist of one outdoor unit connected to one or more indoor units, or multiple outdoor units connected to multiple indoor units. Each indoor unit is also equipped with a control terminal, which can be one or more of a wired remote control, a wireless remote control, or a mobile terminal. The indoor unit receives user commands through the control terminal and then controls the operation of the fresh air system according to the user commands, such as adjusting the fresh air intake, fresh air cooling / heating, and fresh air supply temperature.

[0035] The fresh air system introduces fresh air through an indoor air supply unit, creating a pressure difference between the indoor and outdoor environments. This pressure difference forces indoor air to flow to the outside through gaps in doors and windows or through ventilation devices such as exhaust fans, thus achieving ventilation. The indoor air supply unit includes a DC motor and a fan. Existing indoor air supply units commonly use AC motors, but AC motors suffer from high power consumption and poor speed regulation. This invention uses a DC motor, which consumes less power than an AC motor at the same speed. Combined with a programmable module, it enables stepless speed regulation, increasing the speed range and ensuring precise adjustment of the fresh air intake of the indoor air supply unit.

[0036] The fresh air system also includes a control unit and a detection unit. The control unit is communicatively connected to the air conditioning unit, the fresh air unit, and the detection unit, respectively, and can be wired and / or wirelessly connected. For example, the control unit and the detection unit can be wirelessly connected via a router. The control unit can adjust the operation of the fresh air unit and the air conditioning unit based on the detection results from the detection unit.

[0037] The detection unit includes one or more of the following: CO2 sensor, particulate matter sensor, formaldehyde sensor, TVOC sensor, temperature sensor, and humidity sensor. These sensors can be integrated or distributed to transmit feedback signals reflecting indoor air parameters (including indoor air quality) to the control unit. Those skilled in the art can select the type, quantity, and model of sensors as needed, or use commercially available sensor products. Different sensor products can be combined to form the detection unit according to different functional and accuracy requirements, thus improving the versatility of the detection unit while meeting personalized usage needs. Typically, the detection unit is installed anywhere in the indoor area, such as at the air outlet of a fresh air system, the return air vent of an air conditioning system, or on a table, wall, or floor within the user's activity area.

[0038] Those skilled in the art can combine air conditioning units and fresh air units according to the actual needs of the usage environment to achieve optimal energy-saving effects. For example, when an air conditioning unit includes multiple indoor units, all or some of the indoor units can be combined with a fresh air unit as needed; when a fresh air unit has one indoor unit, that indoor unit can be combined with all or some of the indoor units of multiple air conditioning units; when a fresh air unit has multiple indoor units, all or some of the indoor units can be combined with indoor units of air conditioning units as needed.

[0039] In the fresh air system of the present invention, the air conditioning unit and the fresh air unit can each have independent refrigerant circuits. For example, the outdoor unit and indoor unit of the air conditioning unit are connected by refrigerant piping to form the air conditioning unit refrigerant circuit, and the outdoor unit and indoor unit of the fresh air unit are connected by refrigerant piping to form the fresh air unit refrigerant circuit. Alternatively, the air conditioning unit and the fresh air unit can each have an indoor unit of the air conditioning unit and an indoor unit of the fresh air unit, but they share an outdoor unit. The indoor unit of the air conditioning unit, the indoor unit of the fresh air unit, and the outdoor unit are connected by refrigerant piping to form the fresh air system refrigerant circuit.

[0040] <Fresh Air Intake Adjustment>

[0041] like Figure 1 As shown, initially, the indoor air supply unit of the fresh air system is in a closed state. This invention provides a control method for a fresh air system, which includes the following steps:

[0042] S1. The detection unit measures the indoor air quality every cycle S and obtains the measured value Z. m m is a positive integer;

[0043] S2, The control unit will detect value Z m The detection value Z is calculated by comparing it with the preset value Z0.m The first difference e between the preset value Z0 and the preset value Z0 m That is, e m =Z m -Z0;

[0044] S3, when the first difference e m When the value is greater than the set value L, the indoor air supply unit is turned on; otherwise, the indoor air supply unit remains closed.

[0045] The set value L can be equal to 0, that is, when the detected value Z m The indoor air supply unit turns on when the preset value Z0 is reached; the set value L can also be less than 0, that is, when the detected value Z0 is reached. m Before reaching the preset value Z0, the indoor air supply unit turns on in advance to improve user comfort.

[0046] S4. After the indoor air supply unit is turned on, the detection unit still detects the indoor air quality every cycle S, and the control unit calculates the first difference e obtained in the current cycle. m The first difference e obtained from the previous cycle m-1 The second difference f between m f m =e m -e m-1 =(Z m -Z0)-(Z m-1 -Z0)=Z m -Z m-1 That is, the second difference f m Simultaneously, the detection value Z obtained in the current period is... m The detection value Z obtained in the previous period m-1 The difference between them.

[0047] S5, The control unit determines the second difference f. m Adjust the amount of fresh air introduced into the indoor air supply unit.

[0048] Since the indoor air supply unit of this invention uses a DC motor capable of stepless speed regulation, it has multiple air supply speeds. The lowest air supply speed corresponds to a DC motor speed of 0, and the indoor air supply unit is in a closed state. The higher the air supply speed, the greater the corresponding DC motor speed, and the greater the amount of fresh air introduced. Therefore, in step S5, the control unit can adjust the air supply speed according to the second difference f. m Switch the air supply speed of the indoor air supply unit.

[0049] In steps S1-S3 above, when the CO2 concentration detected by the detection unit is greater than 700 ppm, or PM2.5 is greater than 75 ug / m³, 3 Or formaldehyde / TVOC greater than 0.1 mg / m³ 3Or when the temperature is above 26℃, the first difference e m If the value is greater than the set value L, the indoor air supply unit will be activated.

[0050] For ease of understanding, the present invention provides an embodiment one, which includes the following steps:

[0051] S10. The detection unit is a CO2 sensor, which detects the CO2 concentration every 5 minutes and obtains the CO2 concentration detection value Z. m ;

[0052] S20, The control unit will detect value Z m The detection value Z is calculated by comparing it with the preset value Z0 = 800 ppm. m The first difference e between the preset value Z0 and the preset value Z0 m ;

[0053] S30, when the first difference e m Greater than the set value L = -100ppm (i.e., the detection value Z) m When the concentration is 700 ppm, turn on the indoor air supply unit; otherwise, keep the indoor air supply unit off.

[0054] S40. After the indoor air supply unit is turned on, the detection unit still detects the CO2 concentration every 5 minutes, and the control unit calculates the second difference value f. m ;

[0055] S51, The control unit, based on the second difference f m To switch the air supply speed of the indoor air supply unit, the following conditions must be met:

[0056] 1) When the second difference f m When the value is greater than 0, the control unit increases the air supply level.

[0057] Second difference f m A value greater than 0 indicates that the CO2 concentration is rising, and the current fresh air intake of the indoor air supply unit is insufficient to reduce the CO2 concentration. It is necessary to increase the fresh air intake to dilute the indoor CO2.

[0058] 2) When the second difference f m When the value is 0, the control unit maintains the air supply level unchanged:

[0059] Second difference f m A value of 0 means that the CO2 concentration is being maintained within a stable (or low) range, thus allowing the current fresh air intake of the indoor air supply unit to remain unchanged.

[0060] 3) When the second difference f m When the value is less than 0, the control unit reduces the air supply level.

[0061] Second difference f m A value less than 0 indicates that the CO2 concentration is decreasing. From an energy-saving perspective, the amount of fresh air introduced can be appropriately reduced to avoid excessive energy consumption.

[0062] As can be seen from Embodiment 1, the present invention is based on the first difference e m To control the opening of the indoor air supply unit, and after the indoor air supply unit is opened, based on the second difference f m This allows for direct adjustment of the fresh air intake of the indoor air supply unit. With this setting, there is no need to compare the detection values ​​obtained from all cycles with the preset values ​​to obtain the corresponding air supply level, saving a lot of complicated calculations. The algorithm is clearer, easier to control, and avoids frequent opening and closing.

[0063] In step S51, switching conditions 1) / 3) allow those skilled in the art to adjust the control unit by increasing / decreasing the air supply level by N increments each time, where N is a positive integer. This control logic is relatively simple and easy to set, and can be adjusted with simple controls, but it may result in insufficient increase in fresh air intake to reduce CO2 concentration.

[0064] Step S51 includes the following steps:

[0065] S511, The control unit, based on the second difference f m Calculate the fresh air increment ΔFan, and then determine the air supply level based on the fresh air increment ΔFan; the formula for calculating the fresh air increment ΔFan is:

[0066] ΔFan=n*f m (1)

[0067] Where the correction amount n>0.

[0068] In equation (1), when the correction amount n is a fixed value, the f obtained in the current period m The larger the value, the larger the required ΔFan for the next cycle, and the more air supply levels the control unit can increase each time, and vice versa. This setting helps to improve control flexibility and increase the accuracy of adjusting the amount of fresh air introduced.

[0069] Furthermore, to improve the energy efficiency of the fresh air system, the correction value n can be set as the first difference e obtained with respect to the current cycle. m The variable, whose range of values ​​is: when e m When ≤L, n=0; when L<e m When n ≤ 0, n and e m Positive correlation; when e m When the value is greater than 0, n = X. Here, the setpoint L < 0, and the setpoint X > 0.

[0070] Preferably, such as Figure 3 As shown, L = -100, X = 1.7, that is, when e m When n ≤ -100, n = 0; when -100 < e m When n ≤ 0, n = 0.017e m +1.7; when e m When n > 0, n = 1.7.

[0071] Combining equation (1), we can see that

[0072] 1) When the indoor air supply unit is in the off state, if e m If -100 ≤ e, the indoor air supply unit remains closed; if -100 < e m ≤0, at this point the CO2 concentration gradually increases, f m If the value is greater than 0, then ΔFan is greater than 0, the indoor air supply unit turns on earlier, and the air supply level changes with e. m and / or f m The concentration increases slowly as the CO2 level rises. This setting improves user comfort and reduces operating costs before the CO2 concentration reaches the preset value.

[0073] 2) When the indoor air supply unit is in the on state, if -100 < e m ≤0, at this point the CO2 concentration gradually decreases, f m If e is less than 0, then ΔFan is less than 0, and the air supply level follows e. m and / or f m The air supply speed gradually decreases until it reaches the lowest setting, at which point the indoor air supply unit shuts off. This setting allows the amount of fresh air introduced into the indoor air supply unit to decrease slowly when the CO2 concentration drops below the preset value, thus reducing operating costs.

[0074] To further achieve precise control of the air volume of the fresh air system, the present invention also provides a second embodiment. The difference between the second embodiment and the first embodiment is that step S52 is used instead of step S51.

[0075] Step S52 includes: the control unit adjusts the correction amount based on the detected value, the first difference, and the second difference, and substitutes the first difference, the second difference, and the adjusted correction amount into the PID algorithm formula to obtain the fresh air increment ΔFan. Then, based on the fresh air increment ΔFan, the control unit switches the air supply level of the indoor air supply unit to adjust the fresh air intake of the indoor air supply unit. The PID algorithm formula is:

[0076] ΔFan=kp×n×f m +ki×(S / 2×Si)×(e m +e m-1 )+kd×(S / 2×Si)×f m (2)

[0077] Where S is the period, specifically 5 min; Si is the given parameter value, specifically 3; kp, n, ki, and kd are correction values.

[0078] like Figure 3 As shown, in equation (2), the correction amount n is the first difference e obtained with respect to the current period. m The variable, taking CO2 concentration as an example:

[0079] If the first difference e obtained in the current period m Within the first set range, for example, e m When the value is between -100ppm and 0ppm, e m The larger the value of n, the closer the CO2 concentration detected in the current cycle is to the preset value Z0. At this point, n increases with e. m The value increases with the increase of e, and correspondingly, the change in the air supply level also increases with e. m The size increases accordingly, ensuring that the indoor air supply unit starts in advance, improving user comfort;

[0080] If e m If the concentration is greater than 0 ppm, it indicates that the CO2 concentration in the current cycle is greater than the preset value Z0. The indoor air supply unit continues to operate. At this time, n is a constant value greater than 0 (e.g., 1.7), which does not change with e. m The changes then affect the airflow level;

[0081] If e m If the concentration is less than -100ppm, it indicates that the CO2 concentration in the current cycle is much lower than the preset value Z0. At this time, n is 0, which does not affect the change of the air supply level.

[0082] like Figure 4 As shown, in equation (2), the correction amount kp is the second difference f obtained with respect to the current period. m The variable, taking CO2 concentration as an example:

[0083] If the first difference e obtained in the current period m The first difference e obtained from the previous cycle m-1 The second difference f between m Within the first set range, for example f m When the concentration is between -10ppm and 10ppm, it can be seen that the difference between the CO2 concentration values ​​detected in two adjacent cycles is very small, that is, the CO2 concentration is in a stable range. At this time, kp is 0, which does not affect the change of the air supply level.

[0084] If f m Within the second set range, for example, f mWhen the concentration is between -50ppm and -10ppm, it can be known that the CO2 concentration detected in the current cycle is less than the CO2 concentration detected in the previous cycle. m The smaller the value, the faster the CO2 concentration decreases; at this point, kp increases with f. m The decrease in f corresponds to the increase in f, and the corresponding air supply level also increases with f. m The decrease is due to the decrease;

[0085] If f m Within the third set range, for example f m When the concentration is between 10 ppm and 50 ppm, it can be known that the CO2 concentration detected in the current cycle is greater than the CO2 concentration detected in the previous cycle. m The larger the value, the faster the CO2 concentration increases; at this point, kp increases with f. m The value increases with the increase of f, and correspondingly, the air supply level also increases with f. m It increases with the increase of;

[0086] When f m When the absolute value of kp exceeds a certain value, such as greater than 50 ppm or less than -50 ppm, it indicates that the CO2 concentration in the current cycle is changing drastically. Considering the operating noise of the indoor air supply unit, kp is a constant value greater than 0 at this time (e.g., when f...). m When >50, kp = 1; f m When f < -50, kp = 0.5), meaning kp does not change with f. m Changes in airflow settings can affect the airflow level, preventing noise caused by sudden changes in airflow settings and thus avoiding auditory discomfort for users.

[0087] like Figure 5 As shown, the correction amount ki is related to the detection value Z obtained in the current period. m The variable, taking CO2 concentration as an example:

[0088] If the detection value Z obtained in the current period m Within the first set range, for example, Z m When the concentration is 750ppm to 850ppm, it can be seen that the CO2 concentration detected in the current cycle fluctuates slightly around the preset value Z0. At this time, ki is 0, which does not affect the change of the air supply level.

[0089] If Z m Within the second set range, for example, Z m When the concentration is between 600 ppm and 750 ppm, it can be known that the CO2 concentration detected in the current cycle is less than the preset value Z0. At this time, ki increases with Z. m The increase of decreases;

[0090] If Z m Within the third setting range, for example, Z mWhen the concentration is between 850 ppm and 1200 ppm, it can be seen that the CO2 concentration detected in the current cycle is greater than the preset value Z0. At this time, ki increases with Z. m It increases with the increase of;

[0091] When Z m If the concentration exceeds a certain value, such as greater than 1200 ppm or less than 600 ppm, it indicates that the CO2 concentration detected in the current cycle is much higher or much lower than the preset value Z0. In this case, ki is a fixed value greater than 0 (e.g., when Z0 > 0). m When >1200, ki = 1; f m When Z < -600, ki = 0.5), meaning ki does not change with Z. m The changes then affect the air supply level.

[0092] like Figure 6 As shown, the correction amount kd is related to the third difference g. m The variable, the third difference g m The second difference f obtained for the current period m The second difference f obtained from the previous cycle m-1 The difference between them, i.e., g m =f m -f m-1 Taking CO2 concentration as an example:

[0093] If the third difference g obtained in the current period m Within the first set range, for example, g m When the concentration is between -2ppm and 2ppm, it can be seen that the difference between the CO2 concentration values ​​detected in three adjacent cycles is very small, that is, the CO2 concentration is within a stable range. At this time, kd is 0, which does not affect the change of the air supply level.

[0094] If g m Within the second set range, for example, g m When the concentration is between -10ppm and -2ppm, it can be seen that the CO2 concentration change in the current two cycles is less than that in the previous two cycles. m The smaller the value, the faster the CO2 concentration decreases; at this point, kd increases with g. m As g decreases, g increases; correspondingly, the airflow level also increases with g. m The decrease is due to the decrease;

[0095] If g m Within the third setting range, for example, g m When the concentration is between 2 ppm and 10 ppm, it can be seen that the CO2 concentration change in the current two cycles is greater than that in the previous two cycles. m The larger the value, the faster the CO2 concentration increases; at this point, kd increases with g. mThe value increases with the increase of g, and correspondingly, the air supply level also increases with g. m It increases with the increase of;

[0096] When g m When the absolute value of kd exceeds a certain value, such as greater than 10 ppm or less than -10 ppm, it indicates a rapid change in CO2 concentration. Considering the operating noise of the indoor air supply unit, kd is a constant value greater than 0 at this time (e.g., when g...). m When >10, kd=1; g m When kd < -10, kd = 0.5, meaning kd does not change with g. m Changes in airflow settings can affect the airflow level, preventing noise caused by sudden changes in airflow settings and thus avoiding auditory discomfort for users.

[0097] Combining formula (2) and Figure 3-6 It can be seen that,

[0098] 1) When Z1=Z2=Z3=600, ΔFan=0.5×7.5×(-400)=-1500;

[0099] 2) When Z1 = Z2 = 700 and Z3 = 750, ΔFan = 1 × 0.85 × 50 + 0.025 × 7.5 × (-150) + 1 × 7.5 × 50 = 389.375;

[0100] 3) When Z1 = Z2 = 800 and Z3 = 700, ΔFan = 0.19 × 7.5 × (-100) + 0.5 × 7.5 × (-100) = -517.5;

[0101] 4) When Z1 = Z2 = Z3 = 850, ΔFan = 0;

[0102] 5) When Z1=Z2=Z3=1200, ΔFan=(0.0029×1200-2.43)×7.5×800=6300.

[0103] Compared to Equation (1), Equation (2) can comprehensively calculate ΔFan based on the detection value, the first difference, the second difference, and the degree of change of the second difference (i.e., the third difference) in different cycles, so as to achieve: when the detection value is less than the preset value, the fresh air intake decreases as the detection value decreases; when the detection value fluctuates near the preset value, the fresh air intake remains unchanged, allowing reasonable fluctuations in the detection value; when the detection value is greater than the preset value, the fresh air intake increases as the detection value increases, thereby making the control of the fresh air intake more precise and intelligent, improving the energy efficiency of the fresh air system, and reducing the user's operating costs.

[0104] Those skilled in the art can adjust the range of values ​​of S, Si and correction values ​​kp, n, ki and kd in equation (2) as needed.

[0105] Combination Figure 2 It can be seen that, between steps S4 and S5 of the present invention, there is also step S401: if all the first differences obtained within the first set time period t1 are less than the set value L, the indoor air supply unit is turned off. Here, the first set time period t1 is greater than the period S. Compared to the opening condition of the indoor air supply unit (the first difference obtained in the current period is greater than the set value L), the closing condition of the indoor air supply unit set in step S401 takes more first differences into consideration. To close the indoor air supply unit, the condition must be met: multiple first differences obtained within the first set time period t1 are all less than the set value L. This can effectively reduce the repeated opening and closing of the indoor air supply unit caused by fluctuations in the detected values, thereby improving user comfort and extending the service life of the fresh air system.

[0106] Furthermore, between steps S401 and S5, step S402 is also included: after the detection unit continues to run for a second set time period t2, the control unit predicts the detection value that the detection unit can obtain after running for a third set time period t3 based on the detection value obtained by the detection unit during the second set time period t2, obtains the predicted detection result value, and then calculates the fourth difference between the predicted detection result value and the detection value obtained in the current cycle.

[0107] If the fourth difference is greater than 0, it means that the current fresh air intake of the indoor air supply unit is insufficient to reduce the detection result within the third set time period t3, and the control unit should increase the fresh air intake of the indoor air supply unit.

[0108] If the fourth difference is less than or equal to 0, then continue to step S5.

[0109] Regarding step S402, one application example is: 15 people enter a room with an area of ​​100m². 2 In the room, the detection unit detects that the current CO2 concentration in the room is 600ppm and predicts that the CO2 concentration in the room will be 1000ppm after 15 minutes. Since the fourth difference = 1000ppm - 600ppm = 400ppm > 0, the control unit will increase the fresh air intake of the indoor air supply unit. If step S402 is not followed, according to equation (1), the control unit needs to increase the fresh air intake of the indoor air supply unit only when the detection unit detects that the current CO2 concentration in the room is greater than 700ppm. Therefore, step S402 can increase the fresh air intake in advance within the third set time period t3, avoiding the continuous decline of air quality within the third set time period t3, which helps to improve indoor comfort.

[0110] In the control method of this invention, when the detection unit communication is abnormal, the control unit maintains the fresh air intake of the indoor air supply unit unchanged for a fourth preset time period t4, and then shuts down the indoor air supply unit. This setting ensures that the fresh air system continues to work for a period of time after the detection unit communication is abnormal, improving indoor air quality, and then shuts down in time, which not only improves the user experience but also reduces the energy consumption of the fresh air system and lowers the user's operating costs.

[0111] In the control method of this invention, the fresh air system adjusts the amount of fresh air introduced based on indoor air quality detection values. In addition to the CO2 concentration value mentioned above, the control unit can also adjust the amount of fresh air introduced based on one or more of the following detection values: PM2.5 concentration value detected by a particulate matter sensor, formaldehyde concentration value detected by a formaldehyde sensor, TVOC concentration value detected by a TVOC sensor, indoor-outdoor temperature difference value detected by a temperature sensor, and indoor-outdoor humidity difference value detected by a humidity sensor. This reduces the operating energy consumption of the fresh air system while meeting user comfort requirements, thus reducing user operating costs. Furthermore, the fresh air system can simultaneously adjust both the amount of fresh air introduced and the temperature of the introduced fresh air, further enhancing user comfort and saving energy.

[0112] <Fresh Air Temperature Control>

[0113] The fresh air intake unit of a fresh air system introduces fresh air based on indoor air quality to ensure indoor air quality and improve user comfort. In spring and autumn, due to the small temperature difference between indoors and outdoors, adjusting the fresh air intake will not cause discomfort due to the large temperature difference. At this time, the indoor air supply unit of the fresh air intake unit can introduce fresh air, but the refrigerant circuit of the fresh air intake unit does not operate, meaning that the temperature of the introduced fresh air is not regulated. In summer or winter, due to the large temperature difference between indoors and outdoors, adjusting the fresh air intake not only affects user comfort but also impacts the overall energy consumption of the fresh air system. Therefore, before the fresh air is delivered indoors, the supply air temperature of the indoor unit of the fresh air intake unit needs to be adjusted by regulating its operating status. Specifically, the heat exchange of the fresh air flowing through the heat exchange unit can be adjusted by regulating the refrigerant circulation volume in the refrigerant circuit of the fresh air intake unit and / or by adjusting the refrigerant flow rate through the heat exchange unit.

[0114] In the control method of the present invention, the indoor unit of the air conditioner receives a set temperature T sent by the control terminal. For example, the user sends a command to the indoor unit of the air conditioner via a remote control or mobile APP to confirm that the set temperature T is 24°C. The control unit adjusts the supply air temperature of the fresh air introduced by the indoor air supply unit according to the set temperature T. Preferably, the supply air temperature of the indoor air supply unit is adjusted to 24°C. This ensures that the temperature of the fresh air supplied to the room is consistent with the indoor temperature, thereby improving user comfort and the energy efficiency of the fresh air system.

[0115] Considering that the location of the temperature sensor in the indoor unit of the fresh air system, the fresh air volume, and the length of the air supply duct can all cause deviations in the supply air temperature, in cooling mode, the supply air temperature of the indoor air supply unit can be adjusted to be slightly lower than the set temperature T of the air conditioner, for example, 1°C lower; in heating mode, the supply air temperature of the indoor air supply unit can be adjusted to be slightly higher than the set temperature T of the air conditioner, for example, 1°C higher, to ensure that the supply air temperature of the indoor air supply unit is close to the set temperature T of the air conditioner, thereby further improving user comfort and the energy efficiency of the fresh air system.

[0116] The detection unit includes an indoor temperature sensor and an outdoor temperature sensor. The indoor temperature sensor detects the indoor temperature T1, and the outdoor temperature sensor detects the outdoor temperature T2. The control unit adjusts the operating state of the fresh air heat exchange unit based on the difference between the indoor temperature T1 and the outdoor temperature T2, and the set temperature T. In a specific embodiment of the invention, when |T1-T2| ≤ the set value T0, the indoor and outdoor temperature difference is small, and the introduction of fresh air will not cause indoor temperature fluctuations. The electric valve is closed, meaning that the temperature of the fresh air is not regulated by the fresh air heat exchange unit of the fresh air device. When |T1-T2| > the set value T0, the indoor and outdoor temperature difference is large, and the heat exchange capacity of the fresh air heat exchange unit can be adjusted according to the indoor temperature T1 or the set temperature T of the air conditioning device. To ensure that the temperature of the fresh air supplied by the indoor air supply unit is close to the indoor temperature T1 or the set temperature T of the air conditioning unit, the larger the set value T0, the greater the heat exchange capacity of the fresh air heat exchange unit. In this case, the refrigerant flow rate through the fresh air heat exchange unit can be increased by adjusting the opening of the electric valve, and / or the compressor frequency can be adjusted to regulate the amount of refrigerant circulating in the refrigerant circuit to increase the heat exchange capacity of the fresh air unit, thereby regulating the supply air temperature of the indoor unit of the fresh air unit.

[0117] When |T1-T2| exceeds the set value T X Time (set value T) X When the outdoor temperature is extremely cold or hot (greater than the set value T0), in order to ensure the service life of the fresh air device and to avoid excessive wear and tear on the fresh air system, the indoor air supply unit of the fresh air device stops operating, that is, no fresh air is introduced.

[0118] like Figure 7As shown, the air conditioning unit of the fresh air system can have multiple indoor units, which can be installed in different rooms or different indoor areas. Each indoor unit has a set temperature. The control unit adjusts the supply air temperature of the fresh air introduced by the indoor air supply unit based on the average of the multiple set temperatures. In this way, the supply air temperature of the indoor air supply unit can be as close as possible to the set temperature of most of the indoor units, thereby ensuring the comfort of users in different rooms or different indoor areas, while improving the energy efficiency of the fresh air system. Here, the average set temperature of the multiple indoor units is taken as the average of the set temperatures of the operating indoor units.

[0119] The indoor air supply unit can finely adjust the temperature of the fresh air introduced by the fresh air device through the linkage control of the fresh air device and the air conditioning device, so as to achieve the energy-saving effect of the fresh air system while ensuring the user's comfort.

[0120] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A control method for a fresh air system, the fresh air system comprising a detection unit, a control unit, and a fresh air device, characterized in that, The indoor air supply unit of the fresh air device includes a DC motor, and the method includes the following steps: The detection unit measures the indoor air quality every cycle S and obtains the detection value Z. m m is a positive integer; The control unit will detect value Z m The detection value Z is calculated by comparing it with the preset value Z0. m The first difference e between the preset value Z0 and the preset value Z0 m ; When the first difference e m When the value is greater than the set value L, the indoor air supply unit is turned on; After the indoor air supply unit is turned on, the control unit calculates the first difference e obtained in the current cycle. m The first difference e obtained from the previous cycle m-1 The second difference f between m And based on the second difference f m Adjust the amount of fresh air introduced into the indoor air supply unit; The control unit is based on the second difference f m Calculate the fresh air increment, and adjust the fresh air intake of the indoor air supply unit according to the fresh air increment; the formula for calculating the fresh air increment ΔFan is: ΔFan=n*f m , Where the correction amount n is the first difference e obtained with respect to the current period. m Variables; When e m When ≤L, n=0; When L < e m When n ≤ 0, n and e m Positive correlation; When e m When n > 0, n = X; Wherein, the set value L < 0, and the set value X > 0.

2. The control method according to claim 1, characterized in that, The indoor air supply unit has multiple air supply levels; the higher the air supply level, the greater the amount of fresh air introduced. The control unit adjusts the air supply according to the second difference f. m Switch the air supply speed of the indoor air supply unit.

3. The control method according to claim 2, characterized in that, When the second difference f m When the value is greater than 0, the control unit increases the air supply level of the indoor air supply unit; When the second difference f m When the value is 0, the control unit maintains the air supply level of the indoor air supply unit unchanged; When the second difference f m When the value is less than 0, the control unit reduces the air supply level of the indoor air supply unit.

4. The control method according to claim 1, characterized in that, The control unit adjusts the correction amount based on the detected value, the first difference, and the second difference, and calculates the fresh air increment ΔFan based on the first difference, the second difference, and the adjusted correction amount. Then, it adjusts the fresh air intake of the indoor air supply unit based on the fresh air increment ΔFan.

5. The control method according to claim 4, characterized in that, Substituting the first difference, the second difference, and the adjusted correction amount into the PID algorithm formula, the PID algorithm formula is as follows: ΔFan=kp×n×f m +ki×(S / 2×Si)×(e m +e m-1 )+kd×(S / 2×Si)×f m Where S is the period, Si is the given parameter value, and kp, ki, and kd are the correction values.

6. The control method according to claim 1, characterized in that, If the first difference obtained within the first set time period is less than the set value L, the indoor air supply unit is turned off.

7. The control method according to claim 1, characterized in that, The method also includes the following steps: after the detection unit has been running for a second set time period, the control unit predicts the detection value that the detection unit can obtain after running for a third set time period based on the detection value obtained by the detection unit during the second set time period, obtains the predicted detection result value, and then calculates the fourth difference between the predicted detection result value and the detection value obtained in the current period.

8. The control method according to claim 7, characterized in that, When the fourth difference is greater than 0, the control unit increases the amount of fresh air introduced into the indoor air supply unit.

9. The control method according to claim 1, characterized in that, When the detection unit experiences a communication failure, the control unit maintains the fresh air intake of the indoor air supply unit unchanged for a fourth set time period, and then shuts down the indoor air supply unit.

10. The control method according to claim 1, characterized in that, The detection unit includes one or more of the following: CO2 sensor, microparticle sensor, formaldehyde sensor, TVOC sensor, temperature sensor, and humidity sensor.

11. The control method according to claim 1, characterized in that, The fresh air system also includes an air conditioning unit, and the control unit adjusts the supply air temperature of the indoor air supply unit according to the set temperature T of the air conditioning unit.

12. The control method according to claim 11, characterized in that, The detection unit includes an indoor temperature sensor and an outdoor temperature sensor. The indoor temperature sensor detects the indoor temperature T1, and the outdoor temperature sensor detects the outdoor temperature T2. The control unit adjusts the operation of the fresh air device based on the difference between the indoor temperature T1 and the outdoor temperature T2 and the set temperature T.

13. The control method according to claim 12, characterized in that, The fresh air device also includes a fresh air heat exchange unit and an electric valve connected to the fresh air heat exchange unit. When |T1-T2| ≤ the set value T0, the electric valve is closed; when |T1-T2| > the set value T0, the control unit opens the electric valve.

14. The control method according to claim 12, characterized in that, The fresh air device also includes a compressor, and the control unit adjusts the operating frequency of the compressor according to the difference between the indoor temperature T1 and the outdoor temperature T2 and the set temperature T.

15. The control method according to claim 1, characterized in that, The fresh air system includes multiple air conditioning units, each with a set temperature. The control unit adjusts the supply air temperature of the indoor air supply unit based on the average of the multiple set temperatures.

16. A fresh air system, characterized in that, Control is performed using the control method described in any one of claims 1-15.

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