Control device, as well as ventilation device and air purifier

Abstract

To provide a control device that can adjust the state quantity of airborne substances in a room to the amount expected by the user, even when the state quantity detection unit is unable to properly detect the state quantity of airborne substances due to wind generated by a blower. [Solution] The control device 10 controls the operation of a blower 6 that adjusts the state quantities of airborne substances in the indoor air. The control device 10 comprises a state quantity detection unit that detects the state quantities of airborne substances in the indoor air, a storage unit 7 that stores the detected values ​​from the state quantity detection unit, and a control unit 2 that provides feedback control to the blower 6 based on the detected values ​​from the state quantity detection unit so that the detected values ​​from the state quantity detection unit are below a threshold. The control unit 2 calculates the amount of change in the detected values ​​from the state quantity detection unit due to the blowing of air by the blower 6 based on the detected values ​​from the state quantity detection unit, the operating state of the blower 6, and past detected values ​​from the state quantity detection unit stored in the storage unit 7, and adjusts the threshold.

Description

Technical Field

[0001] The present disclosure relates to a control device for controlling a blower that adjusts the state quantity of indoor air, as well as a ventilation device and an air purification device.

Background Art

[0002] In a control device for a blower having a function of adjusting the air quality of indoor air, a state quantity such as the indoor odor concentration or particulate matter is detected by a state quantity detection unit, and the ventilation device is controlled so that the state quantity detected by the state quantity detection unit becomes equal to or less than a preset threshold value. Particulate matter is also called PM (Particulate Matter) 2.5. Then, for example, when the indoor air is contaminated by cigarette smoke or the like beyond a preset threshold value, the ventilation device starts operation, exhausts the contaminated indoor air to the outside, introduces fresh outside air, and performs ventilation until the indoor air reaches a preset cleanliness level.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the air purification system described in Patent Document 1 discloses a method for efficiently reducing air pollution by detecting the pollution of the air blown by a blower that is placed in isolation, using a state quantity detection unit that detects pollutants contained in the air. However, if a heat source such as a heater resistor is installed inside the state quantity detection unit, such as a semiconductor gas sensor, the air generated by the blower will come into contact with the state quantity detection unit and cool the heat source, making it impossible to properly detect the state quantity of substances in the air. As a result, the operation may end without sufficiently purifying the indoor air, causing discomfort to the user, or the air purification operation may continue unnecessarily, consuming unnecessary power and generating operating noise in the air purifier.

[0005] This disclosure was made to solve the above-mentioned problems, and aims to provide a control device that includes a state quantity detection unit having a heat source such as a semiconductor gas sensor inside, and that can adjust the state quantity of airborne substances in a room to the amount expected by the user, even when the state quantity detection unit is cooled by the wind from a blower and the heat source is cooled, making it impossible to properly detect the state quantity of airborne substances. [Means for solving the problem]

[0006] The control device according to this disclosure is a control device for controlling the operation of a blower that adjusts the state quantities of airborne substances in the air of a room, and comprises a state quantity detection unit for detecting the state quantities of airborne substances in the room, a storage unit for storing the state quantity detection values ​​detected by the state quantity detection unit, and a control unit for controlling the output of the blower based on the state quantity detection values ​​and a threshold value, wherein the control unit calculates a corrected threshold value by correcting the threshold value in the first operating state based on a first state quantity detection value (previous detection value) detected by the state quantity detection unit in the first operating state, which is the operating state before the output of the blower changes, and a second state quantity detection value (current detection value) detected by the state quantity detection unit in the second operating state, which is the operating state after the output of the blower changes, and controls the blower based on the corrected threshold value while the second operating state continues. [Effects of the Invention]

[0007] According to this disclosure, even if the heat source built into the state quantity detection unit is cooled by the operating state of the blower and becomes unable to properly detect the state quantity of airborne substances, the state quantity of airborne substances in the room can be adjusted to the amount expected by the user. [Brief explanation of the drawing]

[0008] [Figure 1] Block diagram showing the configuration of a ventilation system equipped with a control device according to Embodiment 1. [Figure 2] This diagram shows the internal structure of the ventilation device according to Embodiment 1, and is a perspective view illustrating the airflow inside the ventilation device. [Figure 3] Circuit diagram of odor sensor 1 according to Embodiment 1 [Figure 4] A time chart illustrating the feedback control operation by the odor sensor 1 according to Embodiment 1. [Figure 5] A time chart illustrating the feedback control operation by the odor sensor 1 according to Embodiment 1. [Figure 6] Flowchart showing the procedure for feedback control of the control unit of the control device according to Embodiment 1 [Figure 7] Circuit diagram of odor sensor 1 according to Embodiment 2 [Figure 8] Time chart for explaining the feedback control operation by the odor sensor 1 according to Embodiment 2 [Figure 9] Time chart for explaining the feedback control operation by the odor sensor 1 according to Embodiment 2 [Figure 10] Flowchart showing the procedure for feedback control of the control unit of the control device according to Embodiment 2 [Figure 11] Block diagram showing the configuration of an air purifier equipped with a control device according to Embodiment 4. [Modes for carrying out the invention]

[0009] The control device according to the embodiment will be described in detail below with reference to the drawings.

[0010] Embodiment 1. FIG. 1 is a block diagram showing the configuration of a ventilation device including a control device according to Embodiment 1. The ventilation device 100 according to Embodiment 1 is a device having a ventilation function capable of adjusting the state quantity of airborne substances in indoor air. The ventilation device 100 includes a control device 10 and a blower 6.

[0011] The state quantity of airborne substances in indoor air includes, for example, the indoor odor concentration and the indoor PM2.5 concentration. The indoor odor concentration is the state quantity of odor components in indoor air. The PM2.5 concentration is the state quantity of PM2.5 in indoor air.

[0012] The control target of the control device 10 according to Embodiment 1 is the ventilation device 100 having a ventilation function capable of adjusting the state quantity of airborne substances in indoor air. That is, the control device 10 automatically performs feedback control on the operation of the ventilation device 100 having a ventilation function capable of adjusting the state quantity of airborne substances in indoor air. More specifically, the control target of the control device 10 is the blower 6.

[0013] The ventilation device 100 has a function of adjusting the state quantity of airborne substances in indoor air, such as the indoor odor concentration and the indoor PM2.5 concentration, by sucking indoor air and exhausting it outdoors. The ventilation device 100 includes a blower 6 to adjust the state quantity of airborne substances in indoor air, such as the indoor odor concentration and the indoor PM2.5 concentration. By exhausting indoor air outdoors by this blower 6, the state quantity of airborne substances contained in indoor air is adjusted. Therefore, the control device 10 automatically performs feedback control on the operation of the blower 6. And the ventilation device 100 can be said to be a state quantity adjustment device having a function of adjusting the state quantity of airborne substances in indoor air.

[0014] The control device 10 is incorporated in the ventilation device 100 and includes an odor sensor 1, a control unit 2, a display operation unit 3, and a drive circuit 4.

[0015] FIG. 2 is a diagram showing the internal structure of the ventilation device 100 according to Embodiment 1. The arrow shown in FIG. 2 indicates the air flow when the blower 6 operates. When the blower 6 operates, indoor air is sucked in from the suction port 8 provided on the left side surface of the ventilation device 100, and blown out from the exhaust port 9 via the blower 6. A duct is connected to the exhaust port 9 and the sucked indoor air is discharged outdoors. The odor sensor 1 is arranged near the suction port 8 to detect the state quantity of airborne substances in the indoor air. In FIG. 2, the odor sensor 1 is arranged below the suction port 8 of the ventilation device 100. In order to detect the state quantity of airborne substances in the indoor air with the odor sensor 1, a detection window (not shown) is provided in the housing of the ventilation device 100 so that indoor air can be taken into the portion where the odor sensor 1 is arranged. The detection window only needs to have holes so that indoor air can pass through the portion where the odor sensor 1 is arranged. Further, the portion where the odor sensor 1 is arranged is configured such that the indoor air sucked in from the detection window passes through the odor sensor 1 and is blown out to the blower 6. The amount of indoor air taken in from the detection window via the odor sensor 1 varies due to the operation of the blower 6.

[0016] The odor sensor 1 is a state quantity detection unit that detects the indoor odor concentration, which is the state quantity of airborne substances in the indoor air, and outputs the detection result to the control unit 2. That is, the odor sensor 1 is a state quantity detection unit that detects the state quantity of airborne substances in the indoor air and outputs the detection result to the control unit 2. The odor sensor 1 outputs a voltage corresponding to the detection result to the control unit 2. That is, the odor sensor 1 converts the detection result of the indoor odor concentration, which is the state quantity of the indoor state, into a voltage and outputs it to the control unit 2. That is, the detection value of the indoor odor concentration detection result in the odor sensor 1 to the control unit 2 is a voltage value.

[0017] FIG. 3 is a configuration diagram of the odor sensor 1 according to Embodiment 1. Using FIG. 3, the principle by which the odor sensor 1 detects the state quantity of airborne substances will be described. Odor sensor 1 is a semiconductor-type gas sensor that is highly sensitive to gases containing odor components such as tobacco and cooking odors, and is long-lasting and inexpensive. As shown in Figure 3, the semiconductor-type gas sensor has a gas-sensing part 11 and a heater resistor 12 inside. In clean air, the electrons inside the metal oxide semiconductor (e.g., tin oxide) on the surface of the gas-sensing part 11 are captured, making it difficult for current to flow and increasing the sensor resistance value. In air containing reducing gases, the oxygen on the surface of the gas-sensing part 11 reacts with the reducing gas and is removed, freeing up the electrons inside the metal oxide semiconductor, making it easier for current to flow and decreasing the sensor resistance value. This principle is used to detect the gas concentration contained in the air. A heater resistor 12 is necessary to raise the temperature around the gas-sensing part 11 in order to cause a chemical reaction between oxygen and reducing gas. Various semiconductor-type gas sensors are available depending on the gas to be detected.

[0018] As mentioned above, since the odor sensor 1 detects gas concentration in a high-temperature environment, it is temperature-dependent, and the sensor resistance value changes with ambient temperature, causing the detected value to change. When the air generated by the operation of the blower 6 hits the odor sensor 1 and the ambient temperature of the odor sensor 1 decreases, the chemical reaction between oxygen and reducing gas slows down, causing the sensor resistance value to increase. In this case, the detected value of the odor sensor 1 changes as shown in Figure 4.

[0019] On the other hand, it is also possible that the surface temperature of the gas-sensing section 11 decreases as it is exposed to the airflow from the blower 6, causing the sensor resistance value to decrease. In the configuration diagram of Figure 3, when the sensor resistance value of the odor sensor 1 decreases, the sensor detection voltage increases, so the detected value of the odor sensor 1 changes as shown in Figure 5.

[0020] Whether the odor sensor 1's resistance increases or decreases when the airflow from the blower 6 hits it depends on the type of sensor and the materials used in the semiconductor. Therefore, the detected value of the odor sensor 1 could be either as shown in Figure 4 or Figure 5. In either case, the airflow from the blower 6 hitting the odor sensor 1 prevents accurate detection of the gas concentration in the indoor air.

[0021] The control unit 2 is equipped with a microcomputer and uses the drive circuit 4 to feedback control the operation of the blower 6 so that the detected value of the odor sensor 1 is below a preset threshold. The control unit 2 performs feedback control using the detected value of the odor sensor 1 to control the operation of the blower 6.

[0022] The display and operation unit 3 includes switches for receiving operation commands from the user to the ventilation device 100 and a display device for informing the user of the operating status of the ventilation device 100. A communication unit (not shown) may be provided in the display and operation unit 3 so that operation commands to the ventilation device 100 are made by the remote controller 5. Hereafter, the remote controller will simply be referred to as the remote control.

[0023] The drive circuit 4 controls the operation of the blower 6 according to the control of the control unit 2.

[0024] The remote control 5 receives operation commands for the ventilation system 100 from the user and transmits them to the control unit 2. The remote control 5 is a remote control device for the user to start and stop the operation of the ventilation system 100. The remote control 5 receives commands from the user regarding the operation control of the ventilation system 100. The remote control 5 transmits the various commands received from the user to the control unit 2. The remote control 5 may be a dedicated remote control for the ventilation system 100, or it may be a terminal device such as a smartphone that has application software capable of remotely controlling the ventilation system 100 installed and can communicate with the communication unit included in the display operation unit 3. Embodiment 1 will describe the case where the remote control 5 is a dedicated remote control for the ventilation system 100.

[0025] The remote control 5 is an interface for remotely controlling the operation of the ventilation device 100, which has the same functions as the display and operation unit 3, and receives operations related to the operation of the ventilation device 100 from the user. When the remote control 5 receives an operation from the user, it generates a signal corresponding to the user's operation as an operation signal. The operation signal generated by the remote control 5 communicates with the communication unit included in the display and operation unit 3. The communication between the remote control 5 and the display and operation unit 3 may be wireless or wired. In Embodiment 1, the remote control 5 and the display and operation unit 3 are wirelessly connected, and the communication between the remote control 5 and the display and operation unit 3 is wireless.

[0026] The blower 6 operates under the control of the control unit 2 and the drive circuit 4 to provide airflow for ventilation of the room. The operating state before the output of the blower 6 changes is referred to as the first operating state, and the operating state after the output of the blower 6 changes is referred to as the second operating state.

[0027] Next, the basic feedback control performed by the control unit 2 of the control device 10 according to Embodiment 1 will be described. Figure 6 is a flowchart showing the procedure of feedback control by the control unit 2 of the control device 10 according to Embodiment 1. Figure 4 is a time chart for explaining the basic feedback control operation of the control device 10 according to Embodiment 1. The vertical axis in the upper part of Figure 4 represents the detected value when the odor sensor 1 is configured as shown in Figure 3. When the resistance value of the odor sensor 1 increases, the detected value decreases, and when the resistance value of the odor sensor 1 decreases, the detected value increases. In other words, a lower detected value indicates a lower concentration of odor components and cleaner air, while a higher detected value indicates a higher concentration of odor components and polluted air. The horizontal axis in the upper part of Figure 4 is time. The vertical axis in the lower part of Figure 4 is the control state of the blower 6. The horizontal axis in the lower part of Figure 4 is time.

[0028] Under the control of the control device 10, the blower 6 starts feedback control at time T0, as shown in the time chart in Figure 4, and its operating state is determined according to the value detected by the odor sensor 1. In Figure 4, from time T0 to time T1, the blower 6 is stopped because the value detected by the odor sensor 1 is below a preset threshold (in Figure 4, the threshold is explained as 2.5V). At time T1, if the value detected by the odor sensor 1 becomes 2.5V or higher, the blower 6 starts operating. However, the wind generated by the operation of the blower 6 hits the odor sensor 1, causing the temperature of the heater resistor 12 inside the odor sensor 1 to drop, resulting in a 0.2V decrease in the value detected by the odor sensor 1.

[0029] Here, the control unit 2 calculates the change in the value detected by the odor sensor 1 immediately before the blower 6 starts operating compared to the change in the value detected by the odor sensor 1 due to the blower 6 operating and the resulting airflow, and corrects the threshold value based on this change.

[0030] The procedure for correcting the threshold is explained using the flowchart in Figure 6. Here, the threshold used when the blower 6 is stopped is defined as the "set threshold," and the threshold used when the blower 6 is running is defined as the "corrected threshold." Note that the flowchart in Figure 6 assumes that the detected value of the odor sensor 1 fluctuates as shown in the time chart in Figure 4 or Figure 5.

[0031] First, in step S110, at time T0, the control device 10 acquires the detected value of the odor sensor 1 (hereinafter referred to as the "odor sensor detected value").

[0032] In step S120, the "odor sensor detection value" obtained in step S110 is compared with the "set threshold." Here, since the blower 6 is stopped, the "set threshold" is used. The "set threshold" is a threshold value set in advance by the user. If the "odor sensor detection value" is less than the "set threshold," the system returns to step S110 without taking any action (step S120: No). In short, the blower 6 remains in standby mode without operating until the "odor sensor detection value" becomes equal to or greater than the "set threshold." If the "odor sensor detection value" becomes equal to or greater than the "set threshold," the system proceeds to step S130 (step S120: Yes).

[0033] In step S130, the "odor sensor detection value" obtained in step S110 is stored in the "first state quantity detection value" (previous detection value) as the detection value immediately before the blower 6 starts operation.

[0034] In step S140, the blower 6 is started.

[0035] In step S150, the "odor sensor detection value" is obtained after the blower 6 has been operated. In step S155, the "odor sensor detection value" obtained in step S150 is stored in the "second state quantity detection value" (current detection value) as the detection value after the blower 6 has started operating. In step S160, the "second state quantity detection value" and the "first state quantity detection value" are compared to calculate the change in the "odor sensor detection value" due to the airflow generated by the operation of the blower 6. If the "second state quantity detection value" is greater than or equal to the "first state quantity detection value" (step S160: Yes), the process proceeds to step S170, where the detection voltage of the odor sensor 1 has increased due to the airflow from the blower 6 (the detection value of the odor sensor 1 changes as shown in Figure 5), so the "sensor detection change amount" is calculated by subtracting the "first state quantity detection value" from the "second state quantity detection value". At this time, the "sensor detection change amount" is a positive value, so the "sign flag" is set to 0. On the other hand, if the "second state variable detection value" is less than the "first state variable detection value" (step S160: No), the process proceeds to step S180. Since the detection voltage of the odor sensor 1 is decreasing due to the effect of airflow from the blower 6 (the detection value of the odor sensor 1 changes as shown in Figure 4), the "sensor detection change amount" is calculated by subtracting the "second state variable detection value" from the "first state variable detection value". In this case, the "sensor detection change amount" is a negative value, so the "sign flag" is set to 1.

[0036] In step S190, the "first state variable detection value" is updated to the "second state variable detection value" obtained in step S155.

[0037] In step S200, the "sensor detection change amount" calculated in step S170 or step S180 is compared with a preset "change amount threshold." If it is greater than or equal to the "change amount threshold" (step S200: No), the process proceeds to step S220, where the "sensor detection change amount" obtained in either step S170 or step S180 is added to the "cumulative change amount." If it is less than the "change amount threshold" (step S200: Yes), the process proceeds to step S210, where the "cumulative change amount" is stored as the "threshold correction amount." In other words, in step S200, the change amount when the detected voltage value of the odor sensor 1 rapidly increases or decreases is judged to be due to the effect of airflow from the blower 6, and that change amount is set as the "threshold correction amount." In the upper part of the odor sensor detection value graph in Figures 4 and 5, the rapid change in the detected value immediately after the blower operation (large absolute value of the slope of the graph) is detected as being due to the effect of airflow from the blower 6. The "change threshold" is pre-set to distinguish between the change in the value detected by the odor sensor 1 due to the detection of odor components (small slope) and the change due to the airflow from the blower 6 (large slope).

[0038] In step S230, it is determined whether the "second state variable detection value" is greater than or less than the "set threshold" and whether to add or subtract the "target correction value". Specifically, if the "second state variable detection value" is greater than or equal to the "set threshold" (step S230: Yes), the sensor detection value has increased after the blower 6 operation, so the "correction threshold" is... [Correction threshold] = [Setting threshold] + [Threshold correction amount] (Step S240) It is calculated as follows. On the other hand, if the "second state quantity detection value" is less than the "set threshold" (step S230: No), the sensor detection value has decreased after the blower 6 operation, so the "correction threshold" is [Correction threshold] = [Setting threshold] - [Threshold correction amount] (Step S250) It is calculated as follows.

[0039] If a "correction threshold" is set in step S240 or step S250, the "odor sensor detection value" is obtained in step S260. The operation of the blower 6 continues as long as the "odor sensor detection value" is greater than or equal to the "correction threshold" (step S270: No). When the "odor sensor detection value" falls below the "correction threshold" (step S270: Yes), the process proceeds to step S280 to stop the blower 6.

[0040] To explain in detail using the time chart in Figure 4 as an example, the "set threshold" is assumed to be pre-set to 2.5V. When the "odor sensor detection value" becomes 2.5V in step S110, the "odor sensor detection value" ≥ "set threshold" is satisfied in step S120, so the process proceeds to step S130, and the "first state quantity detection value" becomes 2.5V. Then, the process proceeds to step S140, and the blower 6 is operated. Next, when the "odor sensor detection value" becomes 2.3V in step S150, the "second state quantity detection value" becomes 2.3V in step S155, and the "second state quantity detection value" ≥ "first state quantity detection value" in step S160 is not satisfied, so the process proceeds to step S180, and the "sign flag" is set to 1 and the "sensor detection change amount" is calculated. [Sensor detected change amount] = [First state quantity detected value] - [Second state quantity detected value] = 2.5V - 2.3V = 0.2V In step S190, the "first state variable detection value" is updated to 2.3V. To detect rapid changes in the odor sensor 1 due to airflow from the blower 6, the "change threshold" is pre-set to 0.1V. The "change threshold" is a value that can be arbitrarily set considering the timing of acquiring the "odor sensor detection value" and the normal detection fluctuation value of the odor sensor 1, and is not fixed to the "change threshold" = 0.1V used in this example. In step S200, the "sensor-detected change amount" and the "change amount threshold" are compared. If the "sensor-detected change amount" is greater than or equal to the "change amount threshold" (step S200: No), the process proceeds to step S220, where the "sensor-detected change amount" is added to the "cumulative change amount". In Figure 4, the "sensor detected change amount" is 0.2V and the "change amount threshold" is 0.1V or higher, [Integrated change] = [Integrated change] + [Sensor-detected change] = 0 + 0.2V = 0.2V As long as the "sensor-detected change amount" is greater than or equal to the "change amount threshold," it is assumed that the sensor detection is in the process of changing due to the airflow from the blower 6, and therefore the "sensor-detected change amount" is added to the "cumulative change amount." In step S200, until the "sensor detected change amount" falls below the "change amount threshold," the process returns to step S150 and continues from step S150 to step S200. In Figure 4, if we assume that the "odor sensor detection value" = 2.35V is obtained in step S150, then in step S155 the "second state variable detection value" = 2.35V. Since the condition in step S160 that "second state variable detection value" ≥ "first state variable detection value" is satisfied, we proceed to step S170, set the "sign flag" = 0 and calculate the "sensor detection change amount". [Sensor detected change amount] = [Second state quantity detected value] - [First state quantity detected value] = 2.35V - 2.3V = 0.05V In step S190, the "first state variable detection value" is updated to 2.35V. The "sensor change amount" becomes 0.05V, and the "change amount threshold" becomes less than 0.1V (step S200: Yes), so the process proceeds to step S210, where the "threshold correction amount" is set. Here, [Threshold Correction Amount] = [Integrated Change Value] = 0.2V This is the result. In step S230, the "set threshold" and the latest "second state quantity detection value" are compared to check whether the odor sensor detection value has increased or decreased. In the example in Figure 4, the "odor sensor detection value" is 2.35V and the "set threshold" is 2.5V. Since the "odor sensor detection value" is less than the "set threshold" (step S230: No), the process proceeds to step S250 to set the "correction threshold". [Correction threshold] = [Setting threshold] - [Threshold correction amount] = 2.5V - 0.2V = 2.3V In step S260, the "odor sensor detection value" is obtained, and the process proceeds to step S270. If the "odor sensor detection value" is greater than or equal to the "correction threshold" = 2.3V (step S270: No), the process returns to step S260, the "odor sensor detection value" is obtained at a certain interval, and the blower 6 continues to operate. If the "odor sensor detection value" falls below the "correction threshold" (step S270: Yes), the process proceeds to step S280, and the blower 6 is stopped.

[0041] Thus, during the period when the blower 6 is operating in response to the odor sensor 1, the detected value of the odor sensor 1 decreases by 0.2V from the dashed line to the solid line in the upper part of Figure 4. However, by controlling the threshold value by also decreasing it by 0.2V, the blower 6 can be operated for the same period (T1 to T2) as when it is not affected by wind (odor sensor 1 output is the dashed line and the threshold value is 2.5V).

[0042] If threshold correction is not performed, even though the detected value of the odor sensor 1 drops by 0.2V due to the airflow generated by the operation of the blower 6, the threshold is not changed. As a result, the blower 6 will only be operated during the period from T1' to T2', which is the period when the detected value of the odor sensor 1 is above the threshold, as shown in the time chart in Figure 4. Since the period from T1' to T2' is shorter than the period from T1 to T2, there will be insufficient capacity to adjust the odor concentration to the amount expected by the user.

[0043] Furthermore, as shown in the time chart in Figure 5, even when the "odor sensor detection value" rises due to the influence of the airflow from the blower 6, the blower 6 can be operated for an appropriate period by correcting the threshold using the flowchart in Figure 6 and implementing feedback control.

[0044] In Figure 5, if the threshold is not corrected, even though the detected value of the odor sensor 1 rises by 0.2V due to the wind generated by the operation of the blower 6, the threshold is not changed. As a result, the blower 6 continues to operate even after T2, when the detected value of the odor sensor 1 should normally fall below the threshold, and continues to operate until T2', when it falls below the preset threshold. Between T2 and T2', the blower 6 operates unnecessarily, consuming unnecessary power, and the prolonged operating noise of the blower 6 causes discomfort to the user.

[0045] In the flowchart of Figure 6, when acquiring the detected value of the odor sensor 1, the determination may not be made based on a single detected value, but rather the average of multiple detections (for example, 5 times) may be used as the detected value of the odor sensor 1. This suppresses the variation in the detected value of the odor sensor 1, enabling stable feedback control by the odor sensor 1. Furthermore, after switching the operating state of the blower 6, the detected value of the odor sensor 1 will not be stable and will vary considerably for a while. Therefore, by adding processing such as not using the detected value of the odor sensor 1 in the calculation of the threshold correction amount until a predetermined time has elapsed, or not using the value in the calculation of the threshold correction amount if the fluctuation amount of the detected value of the odor sensor 1 exceeds predetermined upper and lower limits, more stable feedback control by the odor sensor 1 can be achieved.

[0046] Therefore, according to the control device 10 of Embodiment 1, even when the wind generated by the operation of the blower 6 blows onto the odor sensor 1, the effect is obtained that the odor concentration in the room can be adjusted to the amount expected by the user.

[0047] Furthermore, the threshold set by the user operating the remote control 5 is set to the concentration of odor components contained in the air (for example, 100 ppm). As mentioned above, the threshold may be the concentration detected by the specific odor sensor 1, or the user may set an abstract value as the threshold, such as setting the sensitivity to odor components to low, medium, or high, or setting the sensitivity level from 1 to 10.

[0048] Similarly, when the ventilation system 100 has three or more operating states, such as stopped, low speed, and high speed, the system uses the detected value of the odor sensor 1 when the blower 6 is stopped as a baseline. Based on the detected value of the odor sensor 1 during each operating state, the system determines how much the detected value changes from the odor sensor 1 detected value data from past operating state changes stored in the memory unit 7, and performs feedback control of the blower 6 by changing the threshold by the same amount as the change.

[0049] Furthermore, in preparation for the first time when the operating state of the ventilation system 100 is switched, for which no past performance data exists, initial data is stored in the memory unit 7 when the ventilation system 100 is manufactured. The initial data is set by the manufacturer based on values ​​verified during the development of the ventilation system 100. When switching the operating state of the ventilation system 100 for the second time or later, the average value of past performance data, including the initial data, shall be used. However, if the number of stored past performance data exceeds a specified number of times (e.g., 30 times), in order to reduce memory capacity and prioritize the use of data for the latest ventilation system 100's installation environment, the past performance data used to calculate the average value may be the average value of only the most recent specified number of times (e.g., 30 times).

[0050] Furthermore, when the control unit 2 switches the operating state of the blower 6 and stores the detected value of the odor sensor 1 in the storage unit 7, it stores the value after a certain period of time has elapsed, which is the period until the detected value of the odor sensor 1 stabilizes. This certain period is determined based on the results of verifying the time it takes for the detected value of the odor sensor 1 to stabilize during the development of the ventilation device 100, and is the time that was stored in the storage unit 7 when the ventilation device 100 was manufactured, for example, 30 seconds.

[0051] Alternatively, after switching the operating state of the blower 6, the control unit 2 may store the detected value of the odor sensor 1 in the storage unit 7, for example, every second, and when the amount of change every second falls below a certain value, it may be considered to have stabilized, and this amount of change due to the switching of the operating state may be adopted and used for subsequent control of the blower 6.

[0052] In Embodiment 1, an odor sensor 1 that detects the odor concentration in the room is shown as the state quantity detection unit for detecting the state quantities of airborne substances in the indoor air. However, the state quantity detection unit is not limited to the odor sensor 1. Other sensors, such as a VOC sensor that detects the VOC (volatile organic compound) concentration in the room, which is a state quantity of airborne substances in the indoor air, may be used as the state quantity detection unit. The feedback control shown in Embodiment 1 can be applied to any semiconductor gas sensor equipped with a heater resistor that has a configuration equivalent to that of the odor sensor 1.

[0053] Embodiment 2. Embodiment 2 describes a case where the circuit configuration of the odor sensor 1 of the control device 10 described above is changed. In Embodiment 2, items not specifically described are the same as in Embodiment 1, and the same functions and configurations are described using the same reference numerals. Furthermore, descriptions of functions and configurations that are the same as in Embodiment 1 are omitted.

[0054] Figure 7 is a diagram of the configuration of the odor sensor 1 according to Embodiment 2, in which the positions of the odor sensor 1 and the resistor 13 are swapped from those in Figure 3. In this configuration, the resistance value of the gas-sensing part 11 increases in clean air, so the detection value of the odor sensor 1 increases, and when there are many odor components in the air, the resistance value of the gas-sensing part 11 decreases, so the detection value of the odor sensor 1 decreases. In other words, the odor sensor 1 configured as in Figure 3 has a high detection value when there are many odor components in the air, whereas the odor sensor 1 configured as in Figure 7 has a low detection value when there are many odor components in the air.

[0055] Furthermore, when the wind generated by the operation of the blower 6 hits the odor sensor 1 and the resistance value of the gas sensing unit 11 increases, in the circuit configuration shown in Figure 7, the detected value of the odor sensor 1 will rise above the correct detected value of the state quantity of the airborne substance. That is, the detected value of the odor sensor changes as shown in the time chart in Figure 8. On the other hand, when the wind generated by the operation of the blower 6 hits the odor sensor 1 and the resistance value of the gas sensing unit 11 decreases, the detected value of the odor sensor 1 decreases as shown in the time chart in Figure 9.

[0056] Figures 8 and 9 are time charts illustrating the basic feedback control operation of the control device 10 according to Embodiment 2, when the odor sensor 1 is configured in the circuit shown in Figure 7. Figure 10 is a flowchart illustrating the feedback control procedure of the control unit 2 of the control device 10 according to Embodiment 2. In the upper diagrams of Figures 8 and 9, the vertical axis represents the detected value of the odor sensor 1, with the change in the detected value of the odor sensor 1 shown as a curve and the threshold value as a straight line. In the circuit configuration of Figure 7, the detected value of the odor sensor 1 increases as the resistance value of the gas sensing unit 11 increases, and decreases as the resistance value of the gas sensing unit 11 decreases. In other words, the fewer odor components in the air and the cleaner the air, the higher the detected value, and the more odor components in the air and the dirtier the air, the lower the detected value. The detection voltage curve of the odor sensor 1 in Figure 7 is an inverted version of the detection voltage curve of the odor sensor 1 in Figures 4 and 5. In the upper diagrams of Figures 8 and 9, the horizontal axis represents time. In the lower diagrams of Figures 8 and 9, the vertical axis represents the operating state of the blower 6. In the lower diagrams of Figures 8 and 9, the horizontal axis represents time.

[0057] As mentioned above, the difference between Figure 4 and Figure 8 is that the detected value of the odor sensor 1 is inverted vertically. Therefore, during the period from T1 to T2 when the blower 6 is operating, in Figure 4 the detected value of the odor sensor 1 decreases from the dashed line to the solid line, but in Figure 7 the detected value of the odor sensor 1 increases from the dashed line to the solid line. Accordingly, in Figure 4 the control unit 2 corrects the threshold from 2.5V to 2.3V (-0.2V), but in Figure 7 the threshold needs to be corrected from 2.5V to 2.7V (0.2V). Figure 10 is a flowchart showing the feedback control procedure of the control unit 2 of the control device 10 according to Embodiment 2. It differs from Figure 6, a flowchart showing the feedback control procedure of Embodiment 1, in the following respects.

[0058] The differences between the flowchart in Figure 6 and the flowchart in Figure 10 are twofold: in step S120 of Figure 6, the condition for judgment is that the "odor sensor detection value" is equal to or greater than the "set threshold," whereas in step S121 of Figure 10, the condition for judgment is that the "odor sensor detection value" is less than or equal to the "set threshold"; and in step S271 of Figure 10, the condition for stopping the fan operation is that the "odor sensor detection value" exceeds the "correction threshold."

[0059] In the circuit configuration of the odor sensor 1 according to Embodiment 2, by correcting the threshold value, the effect of operating the blower 6 for an appropriate amount of time according to the detected value of the odor sensor 1 is achieved, similar to Embodiment 1.

[0060] Embodiment 3. Embodiment 3 describes other functions of the control device 10 described above. In Embodiment 3, items not specifically described are the same as in Embodiments 1 and 2, and the same functions and configurations are denoted by the same reference numerals. Furthermore, descriptions of functions and configurations that are the same as in Embodiments 1 and 2 are omitted.

[0061] In Embodiment 3, the method of reflecting past performance data stored in the memory unit 7 in the control of the blower 6 differs from that of Embodiments 1 and 2.

[0062] The control unit 2 stores the detected value of the odor sensor 1 in the memory unit 7 before and after switching the operating state of the blower 6. However, if the state of odor concentration in the room changes significantly at the same time as the operating state is switched, the change in the odor sensor 1's detected value due to the effect of airflow on the odor sensor 1 may be masked by this change, making it difficult to accurately grasp the effect of airflow on the odor sensor 1. For example, if a strong odor is generated when cooking begins, the detected value of odor sensor 1 will rise significantly. Conversely, if the range hood fan is activated, the cooking odor will be rapidly exhausted, which may cause the detected value of odor sensor 1 to drop significantly. Therefore, the control unit 2 performs control such that the detection values ​​from the odor sensor 1, recorded under accidental specific conditions, are not reflected in the control of the blower 6.

[0063] One method involves calculating the average value of the remaining data points (for example, 28 data points if the arbitrary number of trials is 30, excluding the cases where the maximum and minimum changes occurred) from a set of data points (e.g., 30 trials) and using this average value to calculate the threshold. Furthermore, in order to obtain data that more accurately reflects only the effect of wind hitting the odor sensor 1, it is also possible to use the average value of 24 values, for example, by excluding the 3 largest and 3 smallest values ​​(a total of 6 values), rather than just the maximum and minimum values.

[0064] Furthermore, since it is unlikely that a significant change in the effect of airflow on the odor sensor 1 would occur even if the installation environment of the ventilation device 100 changes, it is acceptable to adopt only the data that falls within an arbitrary range from the initial data stored in the memory unit 7 during manufacturing. For example, if the change in the initial data is 0.2V, only the data that falls within the range of -50% (0.1V) to +50% (0.3V) would be adopted.

[0065] Alternatively, the control unit 2 may be equipped with a clock function, and the system may be operated daily during late-night hours (for example, 2 AM) when changes in the state of odor concentration in the room are unlikely to occur, with the aim of measuring the effect of airflow on the odor sensor 1 and acquiring the data.

[0066] Embodiment 4. In Embodiments 1 to 3, the case in which the control device 10 is implemented in the ventilation device 100 was shown, but the control device 10 may also be implemented in the air purifier.

[0067] Figure 11 is a block diagram showing the configuration of the air purifier according to Embodiment 4. The air purifier 200 according to Embodiment 5 is a device equipped with an air purification function that can adjust the state amounts of airborne substances in the indoor air. The air purifier 200 comprises a control device 20, a blower 6, and an electrostatic precipitator 21.

[0068] The control device 20 according to Embodiment 4 controls an air purifier 200 equipped with an air purification function that can adjust the state amounts of airborne substances in the indoor air. In other words, the control device 20 automatically provides feedback control of the operation of the air purifier 200 equipped with an air purification function that can adjust the state amounts of airborne substances in the indoor air.

[0069] In the ventilation system 100, the control device 10 controls only the blower 6, whereas in the air purification system 200, the control device 20 controls both the blower 6 and the electrostatic precipitator 21. In the case of the ventilation system 100, the blower 6 draws in indoor air and discharges it outdoors in order to adjust the state amounts of airborne substances in the indoor air. On the other hand, in the case of the air purification system 200, the blower 6 draws in indoor air, passes it through the electrostatic precipitator 21 to capture airborne substances, and then blows clean air into the room in order to adjust the state amounts of airborne substances in the indoor air.

[0070] The control device 10 of the air purifier 200 according to the above-described embodiment 4 provides feedback control to the air purifier 200 until the indoor air reaches a preset cleanliness level by correcting the threshold even when the air generated by the blower 6 hits the odor sensor 1, thereby adjusting the indoor odor concentration to a level of cleanliness that does not cause discomfort to the user. In other words, even when the air generated by the blower 6 hits the odor sensor 1, the control device 10 of the air purifier 200 continuously controls the air purification operation of the air purifier 200 so that the indoor odor concentration remains below the threshold, thereby adjusting the indoor odor concentration to the level expected by the user and improving indoor comfort.

[0071] Therefore, according to the air purifier 200 of Embodiment 4, even when the air generated by the blower 6 blows onto the odor sensor 1, which is the state quantity detection unit, the state quantity of airborne substances in the room can be adjusted to the amount expected by the user.

[0072] Examples of aspects that may be included in this disclosure are listed below as an addendum. (Note 1) A control device for controlling the operation of a fan that adjusts the state quantities of airborne substances in indoor air, A state quantity detection unit for detecting the state quantities of substances in the air inside the room, A storage unit that stores the state quantity detection value detected by the state quantity detection unit, A control unit that controls the output of the blower based on the detected state value and threshold, Equipped with, The control unit calculates a corrected threshold value based on the first operating state (previously detected value) detected by the state quantity detection unit in the first operating state (before the output of the blower changes) and the second operating state (currently detected value) detected by the state quantity detection unit in the second operating state (after the output of the blower changes), and controls the blower based on the corrected threshold value while the second operating state continues. A control device characterized by the following features. (Note 2) The control unit calculates the amount of change in the state quantity between the first state quantity detection value and the second state quantity detection value, and calculates the corrected threshold value by correcting the threshold value based on the amount of change in the state quantity. The control device according to Appendix 1, characterized in that it is a control device. (Note 3) The state quantity detection unit is a semiconductor gas sensor positioned in communication with the room and the blower, and has a heat source inside. A control device as described in Appendix 1 or Appendix 2, characterized by the above. (Note 4) The amount of change in the state variable is the difference between the first detected state variable value and the second detected state variable value. The control device according to Appendix 2, characterized in that it is a control device. (Note 5) The control unit stores the second state quantity detection value in the storage unit after a predetermined time has elapsed since the blower changed to the second operating state. A control device according to any one of the appendices 1 to 3, characterized in that it is a control device. (Note 6) The control unit calculates the correction threshold based on the average value of the past multiple state quantity changes stored in the storage unit. A control device according to any one of the appendices 1 to 3, characterized in that it is a control device. (Note 7) The control unit calculates the correction threshold based only on the most recent predetermined number of state quantity changes from the past state quantity changes stored in the storage unit. A control device according to any one of the appendices 1 to 3, characterized in that it is a control device. (Note 8) The control unit calculates the correction threshold based only on the state quantity change amount, excluding the maximum and minimum state quantity change amounts from the multiple past state quantity change amounts stored in the memory unit. A control device according to any one of the appendices 1 to 3, characterized in that it is a control device. (Note 9) The control unit calculates the correction threshold based on the amount of change in state quantity, which is obtained by excluding the amount of change in state quantity that is greater than or equal to a predetermined upper limit or less than a predetermined lower limit from the past amount of change in state quantity stored in the storage unit. A control device according to any one of the appendices 1 to 3, characterized in that it is a control device. (Note 10) The control unit determines the upper and lower limits based on the amount of change in the state quantity that was previously stored in the memory unit during the manufacture of the blower. The control device according to Appendix 9, characterized in that it is a control device. (Note 11) The control unit includes a clock function and calculates the correction threshold during the late-night hours when the amount of change in the state variable is small. A control device according to any one of the appendices 1 to 3, characterized in that it is a control device. (Note 12) If the first operating state is the stopped state of the blower, then the threshold in the first operating state is a predetermined reference threshold. A control device according to any one of the appendices 1 to 3, characterized in that it is a control device. (Note 13) If the second operating state is the stopped state of the blower, the blower is controlled by the reference threshold while the second operating state continues. The control device according to Appendix 12, characterized in that it is a control device. (Note 14) Equipped with a control device as described in any one of the appendices 1 to 13. A ventilation device characterized by the following features. (Note 15) Equipped with a control device as described in any one of the appendices 1 to 13. An air purifier characterized by the following features. [Explanation of Symbols]

[0073] 1 Odor sensor (state quantity detection unit), 2 Control unit, 3 Display operation unit, 4 Drive circuit, 5 Remote controller, 6 Blower, 7 Memory unit, 8 Intake port, 9 Exhaust port, 10 Control device, 11 Gas sensing unit, 12 Heater resistor, 13 Resistor, 20 Control device, 21 Electrostatic precipitators, 100 Ventilation systems, 200 Air purifiers

Claims

1. A control device for controlling the operation of a fan that adjusts the state quantities of airborne substances in indoor air, A state quantity detection unit for detecting the state quantities of substances in the air inside the room, A storage unit that stores the state quantity detection value detected by the state quantity detection unit, A control unit that controls the output of the blower based on the detected state value and threshold, Equipped with, The control unit calculates a corrected threshold value based on the first operating state (previously detected value) detected by the state quantity detection unit in the first operating state (before the output of the blower changes) and the second operating state (currently detected value) detected by the state quantity detection unit in the second operating state (after the output of the blower changes), and controls the blower based on the corrected threshold value while the second operating state continues. A control device characterized by the following features.

2. The control unit calculates the amount of change in the state quantity between the first state quantity detection value and the second state quantity detection value, and calculates the corrected threshold value by correcting the threshold value based on the amount of change in the state quantity. The control device according to feature 1.

3. The state quantity detection unit is a semiconductor gas sensor positioned in communication with the room and the blower, and has a heat source inside. The control device according to claim 2, characterized in that...

4. The amount of change in the state quantity is the difference between the first detected state quantity value and the second detected state quantity value. The control device according to claim 2.

5. The control unit stores the second state quantity detection value in the storage unit after a predetermined time has elapsed since the blower changed to the second operating state. The control device according to feature 1.

6. The control unit calculates the correction threshold based on the average value of the past multiple state quantity changes stored in the storage unit. The control device according to feature 1.

7. The control unit calculates the correction threshold based only on the most recent predetermined number of state quantity changes from the past state quantity changes stored in the storage unit. The control device according to feature 1.

8. The control unit calculates the correction threshold based only on the state quantity change amount, excluding the maximum and minimum state quantity change amounts from the multiple past state quantity change amounts stored in the memory unit. The control device according to feature 1.

9. The control unit calculates the correction threshold based on the amount of change in state quantity, which is obtained by excluding the amount of change in state quantity that is greater than or equal to a predetermined upper limit or less than a predetermined lower limit from the past amount of change in state quantity stored in the storage unit. The control device according to feature 1.

10. The control unit determines the upper and lower limits based on the amount of change in the state quantity that was previously stored in the memory unit during the manufacture of the blower. The control device according to feature 9.

11. The control unit includes a clock function and calculates the correction threshold during the late-night hours when the amount of change in the state variable is small. The control device according to feature 1.

12. If the first operating state is the stopped state of the blower, then the threshold in the first operating state is a predetermined reference threshold. The control device according to feature 1.

13. If the second operating state is the stopped state of the blower, the blower is controlled at the reference threshold while the second operating state continues. The control device according to claim 12.

14. The control device is provided according to any one of claims 1 to 13. A ventilation device characterized by the following features.

15. The control device is provided according to any one of claims 1 to 13. An air purifier characterized by the following features.

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