WO2024029283A1

WO2024029283A1 - Voltage control program and air purifier

Info

Publication number: WO2024029283A1
Application number: PCT/JP2023/025547
Authority: WO
Inventors: 政士濱谷; 勝己犬飼
Original assignee: ブラザー工業株式会社
Priority date: 2022-08-02
Filing date: 2023-07-11
Publication date: 2024-02-08
Also published as: JP2024020888A

Abstract

Provided are a voltage control program and an air purifier that contribute to minimizing the occurrence of inrush current.　A CPU of this air purifier outputs, to a voltage control unit, a PWM control signal indicating a duty ratio (S62). The CPU receives an instruction to increase a voltage applied to a motor by the voltage control unit to a target voltage. The CPU sets a target setting value that is a duty ratio corresponding to the target voltage if the instruction is received (S41). Until a first computation value, which is the result of proportional computation based on the difference between the target setting value and a command value (n−1) that is a duty ratio indicated by the PWM control signal outputted last time, reaches a prescribed value, the CPU periodically sets a second computation value, which is the result of adding/subtracting the first computation value to/from the command value (n−1) such that the command value (n−1) approaches the target setting value, to a command value (n) that is a duty ratio indicated by the PWM control signal to be output this time (S54).

Description

Voltage control program and air purifier

The present invention relates to a voltage control program and an air cleaner.

The speed control device described in Patent Document 1 performs PI control using the motor speed as a feedback target. The speed control device stores the value of the integral term when the motor is started for the first time. When starting the motor for the second time, the speed control device performs PI control of the motor based on the stored value of the integral term.

Japanese Unexamined Patent Publication No. 58-22592

When the speed control device increases the rotational speed of the motor to a target rotational speed, the motor is subjected to PI control based on the value of the integral term. For this reason, it is conceivable that the output voltage to the motor is suddenly switched to a voltage corresponding to the target rotational speed. If the output voltage to the motor is suddenly switched to a voltage corresponding to the target rotational speed, an inrush current may occur, which may have an adverse effect on circuit components and the like.

An object of the present invention is to provide a voltage control program and an air cleaner that contribute to the advantage of suppressing the generation of inrush current.

The voltage control program according to the first aspect of the present invention is a process for performing PWM control on the voltage control unit in a computer of an air purifier that controls a voltage control unit for driving a motor that rotates a fan. an output process for outputting a PWM control signal indicating a duty ratio to the voltage control unit; a reception process for receiving an instruction to increase the voltage applied to the motor by the voltage control unit to a target voltage; When the instruction is accepted, a first setting process of setting a target set value that is the duty ratio according to the target voltage, and a second calculation value is applied to the output until the first calculation value reaches a predetermined value. A second setting process is executed to periodically set the duty command value (n) which is the duty ratio indicated by the PWM control signal outputted this time by the process, and the first calculation value is changed from the previous value by the output process. The second calculated value indicates the result of proportional calculation based on the difference between the command value (n-1) which is the duty ratio indicated by the outputted PWM control signal and the target setting value, and the second calculation value is It is characterized in that the first calculation value is added to or subtracted from the command value (n-1) so that the value (n-1) approaches the target setting value.

According to the first aspect, the voltage control program contributes to the advantage of suppressing the generation of inrush current.

An air cleaner according to a second aspect of the present invention includes a fan, a motor for rotating the fan, a voltage control section for driving the motor, and a processor for controlling the voltage control section, and the processor for controlling the voltage control section. is a process of performing PWM control on the voltage control unit, which includes an output process of outputting a PWM control signal indicating a duty ratio to the voltage control unit, and a process of controlling the voltage applied to the motor by the voltage control unit. a reception process that receives an instruction to increase the voltage to a target voltage; a first setting process that sets a target set value that is the duty ratio according to the target voltage when the instruction is accepted by the reception process; and the output process of the result of proportional calculation based on the difference between the command value (n-1), which is the duty ratio indicated by the PWM control signal output last time, and the target setting value set by the first setting process. The first calculated value is added to or subtracted from the duty command value (n-1) so that the command value (n-1) approaches the target setting value until the first calculated value reaches a predetermined value. and a second setting process of periodically setting the second calculated value of the result to the command value (n) which is the duty ratio indicated by the PWM control signal outputted this time by the output process. shall be.

The second aspect contributes similar advantages to the first aspect.

1 is a perspective view of an air cleaner 1. FIG. FIG. 1 is an exploded perspective view of the air cleaner 1. FIG. FIG. 2 is a sectional view taken along the line III-III shown in FIG. 1; FIG. 3 is a bottom view of the air cleaner 1 with the lower wall 31 omitted. 1 is a block diagram showing the electrical configuration of an air cleaner 1. FIG. 9 is a conceptual diagram of a ring buffer 931. FIG. It is a transition diagram of the state of the air cleaner 1. It is a flowchart of main processing. It is a flowchart of main processing. It is a flowchart of fan control processing. It is a flowchart of fan control processing. It is a graph of duty command value D(n) with respect to time. 3 is a graph of fan voltage FV versus time.

An embodiment of the present invention will be described. In the following description, the orientation of the air cleaner 1 will be used as shown in the figure: up and down, left and right, and front and back.

The mechanical configuration of the air cleaner 1 will be explained with reference to FIGS. 1 to 4. As shown in FIGS. 1 and 2, the air cleaner 1 includes a case 3 and a lid 4. The case 3 has a rectangular parallelepiped shape and is composed of a lower wall 31, an upper wall 32, a front wall 33, a rear wall 34, a left wall 35, and a right wall 36.

An opening 325 is formed in the upper wall 32. The opening 325 has a rectangular shape in plan view. The lid 4 has a shape corresponding to the shape of the opening 325 in plan view, and is attached to and detached from the case 3. When the lid 4 is attached to the case 3, the lid 4 closes the opening 325 (see FIG. 1). When the lid 4 is removed from the case 3, the opening 325 is opened upward (see FIG. 2).

A recess 351 is formed at the bottom of the left wall 35. The recess 351 is recessed rightward from the left wall 35 and includes

walls

352, 353, and 354. The

walls

352 and 353 face each other in the front-rear direction. Wall 354 extends in the front-rear direction between the right ends of

walls

352 and 353, respectively.

At the lower part of the front wall 33, a first changeover switch 8, a second changeover switch 16, and a light emitting part 5 are provided. The first changeover switch 8 is a push button, and is pressed by the user when the state of the air cleaner 1 is changed. The state of the air cleaner 1 will be described later.

The second changeover switch 16 is a non-contact switch, and is operated by the user when the state of the air cleaner 1 is changed. For example, the user operates the second changeover switch 16 by bringing a finger close to the second changeover switch 16. That is, the second changeover switch 16 detects the user's finger located away from the second changeover switch 16 . The light emitting unit 5 is composed of a plurality of LEDs, and emits light of a color depending on the amount of dust, which will be described later, within a predetermined period of time.

Suction ports

51, 52, and 53 are formed in the lid 4, front wall 33, and rear wall 34, respectively. The

suction ports

51, 52, and 53 are each composed of a plurality of slits. The

suction ports

52 and 53 are located above the inner wall 37, which will be described later.

Air outlets

55 and 56 are formed in the left wall 35 and right wall 36, respectively. The

air outlets

55 and 56 are each openings that have a rectangular shape when viewed from the side. The

air outlets

55 and 56 are located above an inner wall 37, which will be described later. Louvers 71 and 72 are fitted into the

air outlets

55 and 56, respectively. Each of the

louvers

71 and 72 is constructed by arranging a plurality of plates in the vertical direction, and adjusts the direction in which air flows.

As shown in FIGS. 2 and 3, an inner wall 37 is provided inside the case 3. The middle wall 37 has a rectangular shape in plan view, and is arranged between the lower wall 31 and the upper wall 32 in the vertical direction. Below, the space surrounded by the lower wall 31, the front wall 33, the rear wall 34, the left wall 35, the right wall 36, and the middle wall 37 will be referred to as a "lower space 19" (see FIG. 3). The space surrounded by the upper wall 32, the front wall 33, the rear wall 34, the left wall 35, the right wall 36, and the middle wall 37 is referred to as an "upper space 10." The lower space 19 and the upper space 10 are partitioned from each other by an inner wall 37.

A filter 6 and

blowers

81 and 82 are arranged in the upper space 10. The filter 6 is attached to the upper space 10 through the opening 325. The shape of the filter 6 when viewed from the left and right with the filter 6 installed in the upper space 10 is a U-shape that opens downward. The upper surface, front surface, and rear surface of the filter 6 face the

suction ports

51, 52, and 53, respectively. The filter 6 collects viruses, dirt, dust, etc. and removes them from the air.

The blower 81 is located to the left of the filter 6. The blower 82 is located to the right of the filter 6. The blower 81 is an axial fan and includes a casing 811, a fan motor 812, and a fan 813. The casing 811 has a rectangular cylindrical shape and is fixed to the left end of the case 3 within the upper space 10.

The fan motor 812 is arranged at the center within the casing 811 and fixed to the casing 811. An output shaft (not shown) of the fan motor 812 extends in the left-right direction. Fan 813 is disposed within casing 811 and fixed to the output shaft of fan motor 812. The axis of the fan 813 extends in the left-right direction. The fan 813 is driven by the fan motor 812 to rotate around its axis. As a result, the fan 813 generates an airflow from the right to the left.

The blower 82 has the same structure as the blower 81. That is, the blower 82 includes a casing 821, a fan motor 822, and a fan 823. The support portion 821 corresponds to the casing 811. Fan motor 822 corresponds to fan motor 812. Fan 823 corresponds to fan 813. The fan 823 is driven by the fan motor 822 to rotate around its axis. As a result, the fan 823 generates an airflow from the left to the right.

As shown in FIG. 4, connection terminals 201 are provided on the wall 354. A power cable (not shown) is connected to the connection terminal 201. In this embodiment, the connection terminal 201 has a current upper limit value defined by the standard. For example, the connection terminal 201 is a terminal defined by the USB TYPE-C (registered trademark) standard. By connecting the power cable to the connection terminal 201, the connection terminal 201 receives power supplied from the external power source to the air cleaner 1 via the power cable.

A suction port 14 is provided in the rear wall 34. The suction port 14 is an opening and is located below the inner wall 37. The right wall 36 is provided with an air outlet 15 . The air outlet 15 is an opening and is located below the inner wall 37.

A control board 9 and a pipe 100 are arranged in the lower space 19. The control board 9 is a board for controlling the air cleaner 1. The pipe 100 extends from the inlet 14 to the outlet 15 while being bent. A dust sensor 18 is provided in the middle of the pipe 100. The dust sensor 18 detects dust contained in the air within the pipe 100 without contacting the dust. In other words, the dust sensor 18 detects dust located away from the dust sensor 18.

With reference to FIG. 3, the air purifying operation by the air purifier 1 will be described. In the air cleaning operation,

fan motors

812 and 822 are driven. This causes the

fans

813 and 823 to rotate. As the

fans

813 and 823 rotate, air is sucked into the upper space 10 from outside the case 3 through the

suction ports

51, 52, and 53. The air sucked into the upper space 10 passes through the filter 6. The filter 6 collects and removes viruses, dirt, dust, etc. from the air sucked into the upper space 10.

The air that has passed through the filter 6 branches to the left or right. The air flowing toward the left is blown out from the upper space 10 to the outside of the case 3 through the air outlet 55. In this case, the air blown out from the air outlet 55 is guided diagonally downward to the left by the louver 71. The air flowing toward the right is blown out from the upper space 10 to the outside of the case 3 through the air outlet 56. In this case, the air blown out from the air outlet 56 is guided diagonally downward to the right by the louver 72. The air blown out from the

air outlets

55 and 56 is air from which viruses, dirt, dust, etc. have been removed by the filter 6. Therefore, the air around the air cleaner 1 is purified.

In this embodiment, the air outlet 15 is located below the air outlet 56. Therefore, as the air blown out from the outlet 56 is guided diagonally downward to the right by the louver 72, an airflow is generated in the pipe 100 from the inlet 14 (see FIG. 4) toward the outlet 15. . As a result, air is sucked into the pipe 100 from outside the case 3 through the suction port 14. The air sucked into the pipe 100 passes through the detection area H by the dust sensor 18. The air that has passed through the detection area H is blown out of the case 3 from inside the pipe 100 through the air outlet 15. During the air cleaning operation, the dust sensor 18 detects dust in the air passing through the detection area H.

The electrical configuration of the air cleaner 1 will be explained with reference to FIG. The control board 9 includes a microcomputer 90, a power supply circuit 20, a fan circuit 60, a drive circuit 163, an AD converter 164, a drive circuit 183, an AD converter 184, and a drive circuit 50.

The microcomputer 90 includes a CPU 91, a ROM 92, a RAM 93, and an input/output interface 94, and controls the air cleaner 1. The CPU 91 functions as a processor, and executes, for example, main processing (see FIGS. 8 and 9). The ROM 92 stores in advance a control program for the CPU 91 to execute main processing, information referenced by the CPU 91 when executing the main processing, and the like. The RAM 93 temporarily stores various data used in the control program. The RAM 93 stores information indicating the current state of the air cleaner 1, for example. The first changeover switch 8 is electrically connected to the input/output interface 94 . When the first changeover switch 8 is pressed by the user, it outputs a detection signal indicating that the switch has been pressed to the CPU 91 .

The power supply circuit 20, the fan circuit 60, the drive circuit 163, the AD converter 164, the drive circuit 183, the AD converter 184, and the drive circuit 50 are each electrically connected to the input/output interface 94. Power supply circuit 20 is electrically connected to connection terminal 201 . The power supply circuit 20 detects the voltage applied through the connection terminal 201 and outputs a detection signal indicating the detected voltage to the CPU 91. The drive circuit 50 is connected to the light emitting section 5. The drive circuit 50 causes the light emitting section 5 to emit light in a color according to a signal from the CPU 91.

The fan circuit 60 is electrically connected to each of the

fan motors

812 and 822. The fan circuit 60 is subjected to PWM control by the CPU 91. The fan circuit 60 drives each of the

fan motors

812 and 822 based on a PWM control signal indicating the duty ratio from the CPU 91.

In this embodiment, the fan circuit 60 includes an ON/OFF switch 61, an analog converter 62, and a DC-DC converter 63. The ON/OFF switch 61 is turned on by an activation signal indicating High (hereinafter referred to as "H") from the CPU 91, and becomes energized. The ON/OFF switch 61 is turned off by an activation signal indicating Low (hereinafter referred to as "L") from the CPU 91, and enters a non-energized state. The analog converter 62 converts the PWM control signal from the CPU 91 into analog, and outputs the PWM control signal as a result of the conversion to the DC-DC converter 63.

The DC-DC converter 63 is activated by an enable signal indicating "H" from the CPU 91. The DC-DC converter 63 becomes inactive by an enable signal indicating "L" from the CPU 91. In the active state, the DC-DC converter 63 boosts, rectifies, and smoothes the voltage input to the fan circuit 60 based on the duty ratio indicated by the PWM control signal from the analog converter 62. In the active state, the DC-DC converter 63 applies a boosted, rectified, and smoothed voltage to the

fan motors

812 and 822. In this embodiment, the DC-DC converter 63 applies a larger voltage to the

fan motors

812 and 822 as the duty ratio indicated by the PWM control signal from the CPU 91 is smaller.

The drive circuit 163 is electrically connected to a light emitting element 161, which will be described later, and controls light emission by the light emitting element 161, which will be described later, based on a signal from the CPU 91. The AD converter 164 is electrically connected to a light-receiving element 162 (described later), converts the amount of received light indicated by a detection signal from the light-receiving element 162 into an AD value (analog-digital conversion value), and outputs it to the CPU 91. The drive circuit 183 is electrically connected to a light emitting element 181, which will be described later, and controls light emission by the light emitting element 181 based on a signal from the CPU 91. The AD converter 184 is electrically connected to a light receiving element 182 (described later), converts the amount of received light indicated by a detection signal from the light receiving element 182 into an AD value, and outputs the AD value to the CPU 91.

The second changeover switch 16 is a reflective optical sensor and includes a light emitting element 161 and a light receiving element 162. The light emitting element 161 is, for example, an LED, and emits light forward from the front wall 33 under the control of the drive circuit 163. The light emitted by the light emitting element 161 is reflected by an object located away from the second changeover switch 16. The target object is, for example, a user's finger. The light receiving element 162 is, for example, a phototransistor, and receives light reflected by a user's finger. The amount of light received by the light receiving element 162 corresponds to the distance from the light receiving element 162 to the user's finger. The second changeover switch 16 outputs a detection signal indicating the amount of light received by the light receiving element 162 to the CPU 91 via the AD converter 164. The CPU 91 detects the user's operation on the second changeover switch 16 based on the amount of light received by the light receiving element 162.

An example of a method by which the CPU 91 detects a user's operation on the second changeover switch 16 will be described with reference to FIG. 6. The RAM 93 is provided with a ring buffer 931 for operation detection. The ring buffer 931 includes a plurality of (11 in this embodiment) storage areas R0 to R10. The storage areas R0 to R10 are arranged in this order in a clockwise direction.

Although FIG. 6 conceptually shows the ring buffer 931 in a ring shape for the sake of explanation, in reality, a memory address of the RAM 93 is assigned to each of the storage areas R0 to R10. In the ring buffer 931, the plurality of storage areas R0 to R10 are sequentially processed so as to be arranged in a ring shape based on the assigned memory addresses. Specifically, in the ring buffer 931, processing is performed sequentially from storage area R0 to storage areas R1, R2, . be done.

As described above, the second changeover switch 16 outputs a detection signal indicating the amount of light received by the light receiving element 162 to the AD converter 164. The AD converter 164 sequentially converts the amount of received light indicated by the detection signal received from the second changeover switch 16 into an AD value, and sequentially outputs the AD value of the conversion result to the CPU 91. The CPU 91 sequentially acquires AD values from the AD converter 164 at timing A. The time interval TP between temporally adjacent timings A is constant, for example, 10 ms.

The CPU 91 sets a plurality of consecutive AD values among the plurality of AD values sequentially acquired from the AD converter 164 as one storage target TS. In this embodiment, the plurality of AD values is three or more, for example, five. The CPU 91 removes the minimum value and maximum value from the storage target TS. The CPU 91 calculates the average value of the AD values in the storage target TS from which the minimum value and maximum value have been removed. The CPU 91 stores the calculated average value in the storage area R0. As described above, the CPU 91 sequentially calculates average values and stores the calculated average values in each storage area R0 to R10 in clockwise order. Note that, after storing the average value in the storage area R10, the CPU 91 subsequently stores the next average value in the storage area R0.

The CPU 91 determines whether the number of average values larger than the ON threshold has reached a first predetermined number among the plurality of average values stored in some or all of the plurality of storage areas R0 to R10. The CPU 91 determines that the first switching instruction has been received when the number of average values greater than the ON threshold reaches a first predetermined number. The first predetermined number is, for example, more than half of the number of storage areas R0 to R10. In this embodiment, the number of the plurality of storage areas R0 to R10 is 11, so the first predetermined number is any one of 6 to 11, and is, for example, 6.

For example, in the example shown in FIG. 6, average values of 10, 20, 10, 5, 10, 700, 800, 700, 700, 800, and 800 are stored in each of the storage areas R0 to R10. When the ON threshold is 600 and the first predetermined number is 6, at the time the average value "800" is stored in the storage area R10, the average values exceeding the ON threshold "600" (700, 800, 700, 700, 800, 800) becomes the first predetermined number "6". Therefore, the CPU 91 detects the user's operation on the second changeover switch 16 at the time when the average value "800" is stored in the storage area R10.

Note that after the user's operation on the second changeover switch 16 is detected, the number of average values smaller than the OFF threshold among the plurality of average values stored in some or all of the plurality of storage areas R0 to R10 is determined. When the second predetermined number is reached, the CPU 91 erases the average value from the plurality of storage areas R0 to R10. In this embodiment, the OFF threshold is smaller than the ON threshold.

The dust sensor 18 is a reflective optical sensor and includes a light emitting element 181 and a light receiving element 182. The light emitting element 181 is, for example, an LED, and emits light toward the detection area H under the control of the drive circuit 183. The light emitted by the light emitting element 181 is reflected by the object. The object is, for example, dust. The light receiving element 182 is, for example, a phototransistor, and receives light reflected by dust. The amount of light received by the light receiving element 182 corresponds to the amount of dust. The dust sensor 18 outputs a detection signal indicating the amount of light received by the light receiving element 182 to the CPU 91 via the AD converter 184. The CPU 91 detects the amount of dust based on the amount of light received by the light receiving element 182.

An example of how the CPU 91 detects the amount of dust based on the detection signal from the dust sensor 18 will be described. In this embodiment, the method by which the CPU 91 detects the amount of dust based on the detection signal from the dust sensor 18 is the same as the method by which the CPU 91 detects the user's operation on the second changeover switch 16 . Specifically, like the ring buffer 931, a ring buffer (not shown) for detecting dust is provided in the RAM 93. The ring buffer for dust detection has the same configuration as the ring buffer 931, or has a different number of storage areas.

The CPU 91 stores a plurality of consecutive AD values among the plurality of AD values sequentially acquired from the AD converter 184. The CPU 91 removes the minimum value and maximum value from the storage target. The CPU 91 calculates the average value of the AD values in the storage target from which the minimum value and maximum value have been removed. The CPU 91 stores the calculated average value in the storage area of the ring buffer for dust detection. As described above, the CPU 91 sequentially calculates average values and stores the calculated average values in order in each storage area of the ring buffer for dust detection.

The CPU 91 specifies the amount of dust within a predetermined time period based on a plurality of average values stored in a plurality of storage areas at predetermined time intervals. The CPU 91 causes the light emitting unit 5 to emit light in a color corresponding to the amount of dust within the specified predetermined time via the drive circuit 50.

With reference to FIG. 7, the state of the air cleaner 1 will be explained. There are six states of the air cleaner 1: reset ST0, off ST1, small fan ST2, medium fan ST3, large fan ST4, and error ST5. Hereinafter, the voltage applied to the

fan motors

812, 822 will be referred to as "fan voltage FV", and the target fan voltage FV will be referred to as "target voltage".

Reset ST0 is the state immediately after power is supplied to the air cleaner 1. Off ST1 is a state in which an error condition described below is not satisfied and the target voltage is a predetermined stop voltage. Error ST5 is a state in which the error condition is satisfied and the target voltage becomes the stop voltage. The stop voltage is not limited to a specific value, but is less than 5V in this embodiment. Even when the stop voltage is applied to the

fan motors

812, 822, the

fan motors

812, 822 remain stopped.

Fan small ST2 is a state in which the target voltage is a first voltage higher than the stop voltage. Although the first voltage is not limited to a specific value as long as it is higher than the stop voltage, it is 14V in this embodiment. When a first voltage is applied to

fan motors

812, 822,

fan motors

812, 822 rotate at a first rotational speed.

During fan ST3, the target voltage is a second voltage that is larger than the first voltage. The second voltage is not limited to a specific value as long as it is higher than the first voltage, but is 17V in this embodiment. When a second voltage is applied to the

fan motors

812, 822, the

fan motors

812, 822 rotate at a second rotational speed that is greater than the first rotational speed.

Large fan ST4 is a state in which the target voltage is a third voltage larger than the second voltage. The third voltage is not limited to a specific value as long as it is higher than the second voltage, but is 20V in this embodiment. When the third voltage is applied to the

fan motors

812, 822, the

fan motors

812, 822 rotate at a third rotational speed that is greater than the second rotational speed.

Below, an instruction to switch the state of the air purifier 1 from OFF ST1 to fan small ST2, an instruction to switch the state of the air purifier 1 from fan small ST2 to fan medium ST3, and an instruction to change the state of the air purifier 1 from fan medium ST3 to fan The instructions for switching to large ST4 are collectively referred to as "first switching instructions." The first switching instruction is an instruction to change the state of the air cleaner 1 so that the target voltage increases, and is an instruction to increase the fan voltage FV to the target voltage according to the state of the air cleaner 1.

The instruction to switch the state of the air purifier 1 from large fan ST4 to off ST1 is referred to as a "second switching instruction." The second switching instruction is an instruction to change the state of the air cleaner 1 so that the target voltage is lowered, and is an instruction to lower the fan voltage FV to the target voltage according to the state of the air cleaner 1.

When the first switching instruction and the second switching instruction are collectively referred to as "switching instruction". The user inputs a switching instruction to the air cleaner 1 by operating the first changeover switch 8 or the second changeover switch 16.

When power is supplied to the air cleaner 1 from the external power source via the power cable, the state of the air cleaner 1 becomes reset ST0. Thereafter, the state of the air cleaner 1 switches from reset ST0 to off ST1 (see arrow A1). Thereafter, when the first switching instruction is input, the state of the air cleaner 1 is switched from OFF ST1 to fan small ST2 (see arrow A2). After that, when the first switching instruction is further input, the state of the air cleaner 1 is switched from fan small ST2 to fan medium ST3 (see arrow A3). After that, when the first switching instruction is further input, the state of the air cleaner 1 is switched from fan medium ST3 to fan large ST4 (see arrow A4). After that, when the second switching instruction is input, the state of the air cleaner 1 is switched from fan large ST4 to off ST1 (see arrow A5).

If the error condition is satisfied when the air purifier 1 is in the state of small fan ST2, medium fan ST3, or large fan ST4, the state of the air purifier 1 changes from fan small ST2, fan medium ST3, or fan large ST4 to error ST5. (see arrow A6, arrow A7, arrow A8). After that, the user may turn off the power to the air cleaner 1 and restart the air cleaner 1. As a result, the air cleaner 1 recovers from the error ST5.

In this embodiment, the error condition is that the fan voltage FV becomes below a predetermined error voltage when the

fan motors

812 and 822 are driven, and that the voltage is applied via the connection terminal 201 when the state of the air cleaner 1 is other than reset ST0. For example, the voltage applied to the error voltage becomes less than or equal to a predetermined error voltage.

For example, when the first switching instruction is input to the air cleaner 1, the target voltage increases. In this case, if the fan voltage FV suddenly rises to the changed target voltage, there is a possibility that an inrush current will occur. The CPU 91 contributes to the advantage of suppressing the generation of rush current by executing the main processing described below.

The main processing will be explained with reference to FIGS. 8 and 9. When the state of the air cleaner 1 becomes reset ST0, the CPU 91 reads the control program from the ROM 92 and executes the main process. In the main process, the CPU 91 controls the fan voltage FV by outputting a PWM control signal indicating the duty ratio to the fan circuit 60. Thereby, the CPU 91 controls the rotational speeds of the

fan motors

812 and 822.

Hereinafter, in the main process, the process in which the CPU 91 performs PWM control on the fan circuit 60 and outputs a PWM control signal indicating the duty ratio to the fan circuit 60 will be referred to as "output process." In this embodiment, the processes of S13 (see FIG. 8), S62, S82 (see FIG. 10), and S102 (see FIG. 9), which will be described later, are output processing.

Let "n" be a natural number. The duty ratio indicated by the PWM control signal output in the n-th output process is referred to as "duty command value D(n)." The duty ratio indicated by the PWM control signal output in the (n-1)th output process is referred to as "duty command value D(n-1)." In other words, if the nth output process is the current output process, the (n-1)th output process is the previous output process.

As shown in FIG. 8, when the main process is started, the CPU 91 sets the duty stop value DST to the duty command value D(n) (S11). The duty stop value DST is a reference duty ratio, and is a duty ratio corresponding to a stop voltage.

In the process of S11, the CPU 91 sets the duty stop value DST to the duty command value D(n). As a result, as shown in FIG. 12, a graph L10 in which the duty command value D(n) is plotted against the passage of time becomes a straight line indicating the duty stop value DST until a time point T0 when the process of S25, which will be described later, is performed.

As shown in FIG. 8, the CPU 91 sets a timer initial value to a timer counter T for measuring time (S12). The timer counter T is stored in the RAM 93. Although the timer initial value is not limited to a specific value, it is "0" in this embodiment.

The CPU 91 outputs a PWM control signal indicating the duty command value D(n) set in the process of S11 to the fan circuit 60 (S13). In the fan circuit 60, the analog converter 62 converts the PWM control signal obtained from the CPU 91 into analog. The DC-DC converter 63 converts the voltage input to the fan circuit 60 into a voltage according to the duty command value D(n) as a result of analog conversion. The DC-DC converter 63 applies the converted voltage to the

fan motors

812 and 822 as the fan voltage FV. Note that at the time of the process in S13, the ON/OFF switch 61 is in a non-energized state, so the fan circuit 60 does not apply voltage to the

fan motors

812 and 822. The CPU 91 starts measuring time using the timer counter T (S14). Through the above processing, the state of the air cleaner 1 is switched from reset ST0 to off ST1 (see arrow A1 shown in FIG. 7).

Based on the detection signal from the first changeover switch 8 and the detection signal from the second changeover switch 16, the CPU 91 determines whether the first changeover instruction has been received (S15). In the process of S15, for example, when the CPU 91 acquires a detection signal from the first changeover switch 8, it determines that the first changeover instruction has been received. When the CPU 91 detects the user's operation on the second changeover switch 16, it determines that the first changeover instruction has been received.

If the CPU 91 has not received the first switching instruction (S15: NO), the state of the air cleaner 1 remains OFF ST1, so the CPU 91 returns the process to the determination in S15. When the CPU 91 receives the first switching instruction (S15: YES), the state of the air cleaner 1 is switched from OFF ST1 to fan small ST2 (see arrow A2 shown in FIG. 7).

The CPU 91 determines whether the timer counter T indicates the first standby time or more (S16). Although the length of the first waiting time is not limited to a specific length, in this embodiment, it is 150 ms. If the timer counter T indicates less than 150 ms (S16: NO), the CPU 91 returns the process to the determination in S16. That is, the CPU 91 waits for a first standby time from the time when the state of the air cleaner 1 is switched from reset ST0 to off ST1 until it executes the process from S21 (see FIG. 9) onward. In this embodiment, the air cleaner 1 smoothes the PWM control signal, converts it into an analog value, and operates the DC-DC converter 63. The time required to smooth the PWM control signal corresponds to the first standby time. If the timer counter T indicates 150 ms or more (S16: YES), the CPU 91 advances the process to S21 (see FIG. 9).

As shown in FIG. 9, the CPU 91 outputs an activation signal indicating "H" to the fan circuit 60 (S21). As a result, the ON/OFF switch 61 changes from a non-energized state to an energized state. Therefore, the DC-DC converter 63 converts the voltage input to the fan circuit 60 into a voltage according to the duty command value D(n). The DC-DC converter 63 applies the converted voltage to the

fan motors

812 and 822 as the fan voltage FV. As shown in FIG. 13, a graph L20 plotting the fan voltage FV over time is a straight line showing the voltage V0 corresponding to the duty stop value DST (see FIG. 12) until the time T0 when the process of S25, which will be described later, is performed. becomes. Therefore, the

fan motors

812 and 822 remain in a stopped state until time T0 when the process of S25, which will be described later, is performed.

As shown in FIG. 9, the CPU 91 sets the timer counter T to the timer initial value "0" (S22). The CPU 91 starts measuring time using the timer counter T (S23). The CPU 91 determines whether the timer counter T indicates a second waiting time or more (S24). Although the second waiting time is not limited to a specific time, it is 50 ms in this embodiment.

If the timer counter T indicates less than 50 ms (S24: NO), the CPU 91 returns the process to the determination in S24. In other words, the CPU 91 waits for the second standby time from the time when the ON/OFF switch 61 is switched from the de-energized state to the energized state in the process of S21 until it executes the processes from S25 onwards. This prevents the CPU 91 from performing PWM control on the fan circuit 60 in an unstable state immediately after the fan circuit 60 is energized.

If the timer counter T indicates 50 ms or more (S24: YES), the CPU 91 outputs an enable signal indicating "H" to the fan circuit 60 (S25). As a result, the DC-DC converter 63 changes from an inactive state to an active state. The CPU 91 performs fan control processing (S26).

The fan control process will be explained with reference to FIGS. 10 and 11. As shown in FIG. 10, when the fan control process is started, the CPU 91 sets a duty target value to the duty target set value DTGT (S41). The duty target value is a duty ratio corresponding to the fan voltage FV for driving the

fan motors

812 and 822 at a rotation speed according to the state of the air cleaner 1. The duty target value is stored in advance in the ROM 92 in association with the state of the air cleaner 1.

Specifically, the duty target value corresponding to the small fan ST2 is the duty ratio corresponding to the first voltage (for example, 14V). The duty target value corresponding to ST3 in the fan is the duty ratio corresponding to the second voltage (for example, 17V). The duty target value corresponding to the large fan ST4 is the duty ratio corresponding to the third voltage (for example, 20V).

The CPU 91 determines whether the duty command value D(n) is less than or equal to the duty target setting value DTGT (S42). When the duty command value D(n) is less than or equal to the duty target set value DTGT (S42: YES), there is no need to decrease the duty command value D(n), that is, there is no need to increase the fan voltage FV. In this case, since no rush current is generated, the CPU 91 directly sets the duty target set value DTGT as the duty command value D(n) (S81).

The CPU 91 outputs a PWM control signal indicating the duty command value D(n) set in the process of S81 to the fan circuit 60 (S82). In the fan circuit 60, the DC-DC converter 63 converts the voltage input to the fan circuit 60 into a voltage corresponding to the duty target set value DTGT as the duty command value D(n) indicated by the PWM control signal. The DC-DC converter 63 outputs the converted voltage to the

fan motors

812 and 822 as a fan voltage FV. As a result, the fan voltage FV suddenly drops. The CPU 91 returns the process to the main process.

If the duty command value D(n) is larger than the duty target setting value DTGT (S42: NO), it is necessary to reduce the duty command value D(n) to the duty target setting value DTGT. In other words, it is necessary to raise the fan voltage FV to the target voltage. In this case, since there is a possibility that an inrush current will occur, the CPU 91 gradually brings the fan voltage FV closer to the target voltage by performing the following processing in order to suppress the occurrence of an inrush current.

The CPU 91 sets a predetermined control initial value in the control counter DIC (S43). The control counter DIC is stored in the RAM 93, and is referenced by the CPU 91 in the process of S72 (see FIG. 11), which will be described later. Although the control initial value is not limited to a specific value, it is "0" in this embodiment.

The CPU 91 sets the duty command value D(n) to the duty command value D(n-1) (S51). The CPU 91 uses the duty command value D(n-1) set in the process of S51 to calculate the duty change amount DD based on the following equation (1) (S52). DD={Kp×(D(n-1)-DTGT)}/(2^Kj)...(1)

In other words, the duty change amount DD represents the result of proportional calculation based on the difference between the duty command value D(n-1) and the duty target setting value DTGT. Kp is an integration parameter (constant). Kj is an exponential parameter (constant).

The CPU 91 determines whether the duty change amount DD calculated in the process of S52 is greater than or equal to a predetermined value (S53). The predetermined value is the minimum unit in which the duty command value D(n) can be changed, and is "1" in this embodiment. Immediately after the CPU 91 obtains the first switching instruction, the duty change amount DD is relatively large. The duty change amount DD decreases each time the output process is repeated.

If the duty change amount DD is "1" or more (S53: YES), the CPU 91 subtracts the duty change amount DD from the duty command value D(n-1) to calculate "D(n-1)-DD". The duty command value D(n) is set (S54). The duty command value D(n-1) at the time of processing in S54 is the duty command value D(n) at the time of determination in S42. Therefore, at the time when the process of S54 is performed, the duty command value D(n-1) is larger than the duty target setting value DTGT. Therefore, when the duty change amount DD is subtracted from the duty command value D(n-1), the calculation result approaches the duty target set value DTGT by the duty change amount DD.

In the process of S54, the CPU 91 sets the calculation result "D(n-1)-DD" to the duty command value D(n), thereby calculating the sum of the

fan motors

812 and 822 based on the duty command value D(n). The power consumption [W] of is smaller than the power [W] received by the connection terminal 201.

As will be described in detail later, the CPU 91 periodically performs the process of S54 every 50 ms until the duty change amount DD becomes less than "1" in the process of S53. As shown in FIG. 12, a graph L11 plotting the duty command value D(n) against the passage of time shows that the duty change amount DD is less than "1" in the process of S53 from time T0 when the process of S25 is performed. The curve becomes asymptotic from the duty stop value DST to the duty target set value DTGT until the time point T1 when .

Note that the total power consumption [W] of the

fan motors

812 and 822 is smaller than the power [W] received by the connection terminal 201, and that the duty change amount DD changes along an asymptotic curve over time. The reason for this point is as follows. That is, since Kp and Kj in equation (1) are constants, Kp/2^Kj is a constant. Furthermore, it is set so that Kp/2^Kj<1. In other words, the duty change amount DD is proportional to the difference between the duty command value D(n-1) and the duty target setting value DTGT. The value of Kp×(D(n-1)-DTGT)/2^Kj is the largest immediately after the start of control, and as time passes, the value of Kp×(D(n-1)-DTGT)/2^Kj gradually increases. As it gets smaller, it approaches zero. Therefore, the calculation result over time does not change linearly, but changes along an asymptote that approaches the target value from the value at the start of control. In other words, since the voltage supplied to the

fan motors

812 and 822 also changes along the asymptote, excessive inrush current is suppressed. Therefore, the CPU 91 can make the total power consumption by the

fan motors

812 and 822 smaller than the power received by the connection terminal 201.

The CPU 91 determines whether the duty command value D(n) set in the process of S54 is greater than or equal to the duty target set value DTGT (S61). Although details will be described later, the duty command value D(n) set in the process of S54 will not change from the duty command value D(n-1) when the duty change amount DD becomes smaller than the predetermined value "1". . Therefore, the duty command value D(n) set in the process of S54 does not reach the duty target set value DTGT.

If the duty command value D(n) is greater than or equal to the duty target set value DTGT (S61: YES), the CPU 91 outputs a PWM control signal indicating the duty command value D(n) set in the process of S54 to the fan circuit 60. (S62). In the fan circuit 60, the DC-DC converter 63 converts the voltage input to the fan circuit 60 into a duty command value D(n) indicated by the PWM control signal according to the calculation result "D(n-1)-DD". voltage. The DC-DC converter 63 applies the converted voltage to the

fan motors

812 and 822 as the fan voltage FV. As shown in FIG. 13, a graph L21 plotting the fan voltage FV against the passage of time is from time T0 when the process of S25 is performed to time T1 when the duty variation amount DD becomes less than "1" in the process of S53. Until then, the curve becomes asymptotic from the stop voltage (voltage V0) corresponding to the duty stop value DST to the target voltage (voltage V2) corresponding to the duty target set value DTGT.

In the process of S54, the CPU 91 sets the calculation result "D(n-1)-DD" to the duty command value D(n), so that the duty command value D(n) becomes the duty command value D(n-1). becomes smaller than As a result, in the process of S61, the fan voltage FV based on the duty command value D(n) becomes larger than the fan voltage FV based on the duty command value D(n-1). Therefore, the rotational speeds of

fan motors

812, 822 based on duty command value D(n) are higher than the rotational speeds of

fan motors

812, 822 based on duty command value D(n-1).

As shown in FIG. 10, the CPU 91 determines whether a switching instruction has been received (S63). If the CPU 91 has not received the switching instruction (S63: NO), the state of the air cleaner 1 has not been changed. In this case, the CPU 91 waits for the third standby time (S64). Although the length of the third waiting time is not limited to a specific length, it is 50 ms in this embodiment. After 50 ms have passed, the CPU 91 returns the process to S51. As a result, the CPU 91 periodically performs the processing of S51, S52, S53: YES, S54, S61: YES, S62, S63: NO every 50 ms.

If the CPU 91 receives the switching instruction (S63: YES), the state of the air cleaner 1 is changed. In this case, the CPU 91 determines whether the changed state of the air cleaner 1 is OFF ST1 or error ST5 (S65). In the process of S65, when the CPU 91 receives the second switching instruction, the CPU 91 determines that the state of the air cleaner 1 after the change is OFF ST1 (S65: YES) (see arrow A5 shown in FIG. 7). If the error condition is satisfied, the CPU 91 determines that the state of the air cleaner 1 after the change is an error ST5 (S65: YES) (see arrows A6, A7, and A8 shown in FIG. 7).

If the state of the air cleaner 1 is off ST1 or error ST5 (S65: YES), the CPU 91 returns the process to the main process (see FIG. 9). When the state of the air cleaner 1 is small fan ST2, medium fan ST3, or large fan ST4 (S65: NO), the CPU 91 returns to the process of S41. In this case, the CPU 91 sets the duty target value according to the changed state of the air cleaner 1 as the duty target set value DTGT (S41). The CPU 91 repeats the processing from S42 onwards.

In the determination in S53, each time the process in S54 is performed, the duty change amount DD, which is the result of the proportional calculation in the process in S52, gradually becomes smaller. The predetermined value is the minimum unit in which the duty command value D(n) can be changed. Therefore, if the duty change amount DD is less than the predetermined value, even if the duty change amount DD is subtracted from the duty command value D(n-1) in the process of S54, the calculation result will be the duty command value D(n-1). become the same size. Therefore, when the duty change amount DD becomes less than "1" (S53: NO), the CPU 91 performs a calculation different from the calculation in the process of S54 as follows regarding the duty command value D(n).

As shown in FIG. 11, the CPU 91 adds "1" to the control counter DIC (S71). The CPU 91 determines whether the control counter DIC added in the process of S71 indicates a predetermined counter value (S72). Although the counter value is not limited to a specific value, it is "3" in this embodiment.

When the control counter DIC indicates "1" or "2" (S72: NO), the CPU 91 sets the duty command value D(n-1) to the duty command value D(n) (S73). In this case, the duty command value D(n) does not approach the duty target set value DTGT. The CPU 91 advances the process to determination in S61.

When the control counter DIC indicates "3" (S72: YES), the CPU 91 subtracts the predetermined value "1" from the duty command value D(n-1) to calculate "D(n-1)-1". The duty command value D(n) is set (S74). The duty command value D(n-1) at the time of processing in S74 is the duty command value D(n) at the time of determination in S42. Therefore, at the time when the process of S74 is performed, the duty command value D(n-1) is larger than the duty target setting value DTGT. Therefore, when the predetermined value "1" is subtracted from the duty command value D(n-1), the calculation result approaches the duty target set value DTGT by the predetermined value "1". The CPU 91 sets a control initial value "0" to the control counter DIC (S75). The CPU 91 advances the process to determination in S61.

In the process of S73 or S74, the CPU 91 sets the duty command value D(n-1) or the calculation result "D(n-1)-1" to the duty command value D(n). As a result, as shown in FIG. 12, a graph L12 in which the duty command value D(n) is plotted against the passage of time changes from time T1 when the duty change amount DD becomes less than "1" in the process of S53 to S61. In this process, the duty command value D1 approaches the duty target set value DTGT in a straight line until the duty command value D(n) becomes less than the duty target set value DTGT.

In this embodiment, the CPU 91 executes the process of S74 once every time it executes the process of S73 twice. In the process of S73, the duty command value D(n) does not approach the duty target setting value DTGT, so the slope of the graph L12 becomes gentler due to the process of S73.

As shown in FIG. 10, the CPU 91 makes the determination in S61 described above based on the duty command value D(n) set in the process of S73 or the process of S74. If the duty command value D(n) set in the process of S73 or the process of S74 is greater than or equal to the duty target setting value DTGT, the PWM indicating the duty command value D(n) set in the process of S73 or the process of S74 A control signal is output to the fan circuit 60 (S62). In the fan circuit 60, the DC-DC converter 63 converts the voltage input to the fan circuit 60 into the duty command value D(n-1) or the calculation result "D" as the duty command value D(n) indicated by the PWM control signal. (n-1)-1". The DC-DC converter 63 applies the converted voltage to the

fan motors

812 and 822 as the fan voltage FV.

As shown in FIG. 13, a graph L22 in which the fan voltage FV is plotted against the passage of time shows that from time T1 when the duty change amount DD becomes less than "1" in the process of S53, to the duty command value D in the process of S61. Until time T2 when (n) becomes less than the duty target set value DTGT, the voltage V1 becomes linear approaching the target voltage (voltage V2) corresponding to the duty target set value DTGT.

If the state of the air cleaner 1 has not been changed (S63: NO), the CPU 91 performs the process of S64 described above. The CPU 91 performs the processes of S51 and S52 described above based on the duty command value D(n) set in the process of S73 or S74.

When the process of S73 or the process of S74 is repeated, the duty command value D(n) becomes less than the duty target setting value DTGT in the process of S61 (S61: NO). In this case, the CPU 91 sets the duty target setting value DTGT to the duty command value D(n) (S81).

In the process of S81, the CPU 91 sets the duty target set value DTGT to the duty command value D(n). As a result, as shown in FIG. 12, the graph L13 plotting the duty command value D(n) against the passage of time shows that the duty command value D(n) became less than the duty target setting value DTGT in the process of S61. From time T2, a straight line indicates the duty target setting value DTGT.

As shown in FIG. 10, the CPU 91 outputs a PWM control signal indicating the duty command value D(n) set in the process of S81 to the fan circuit 60 (S82). The CPU 91 returns the process to the main process. Through the process of S82, in the fan circuit 60, the DC-DC converter 63 converts the voltage input to the fan circuit 60 into a voltage corresponding to the duty target set value DTGT as the duty command value D(n) indicated by the PWM control signal. target voltage). The DC-DC converter 63 outputs the converted voltage (target voltage) to the

fan motors

812 and 822 as the fan voltage FV.

As shown in FIG. 13, a graph L23 plotting the fan voltage FV against the passage of time shows that the duty target setting starts from the time T2 when the duty command value D(n) becomes less than the duty target setting value DTGT in the process of S61. A straight line indicates the target voltage (voltage V2) corresponding to the value DTGT. That is, from the time T2 when the duty command value D(n) becomes less than the duty target set value DTGT in the process of S61, the fan voltage FV is fixed to the target voltage (voltage V2). Therefore, the

fan motors

812 and 822 each maintain a state of being driven at a rotational speed according to the target voltage.

Returning to the explanation of FIG. 9. The CPU 91 determines whether the state of the air cleaner 1 is off ST1 or error ST5 (S91). When the state of the air cleaner 1 is small fan ST2, medium fan ST3, or large fan ST4 (S91: NO), the CPU 91 determines whether the first change instruction has been received (S92). If the CPU 91 has not received the first change instruction (S92: NO), the state of the air cleaner 1 has not been changed. In this case, the CPU 91 returns the process to the determination in S91.

If the CPU 91 receives the first change instruction (S92: YES), the state of the air cleaner 1 is changed (see arrows A2, A3, and A4 shown in FIG. 7). In this case, the CPU 91 changes the duty target value to be set as the duty target set value DTGT according to the changed state of the air cleaner 1 (S93). The CPU 91 returns the process to S26. Thereby, as shown in FIG. 10, the CPU 91 sets the changed duty target value to the duty target set value DTGT (S41), and performs the processes from S42 onwards.

If the state of the air cleaner 1 is OFF ST1 or error ST5 in the process of S91 (S91: YES), the CPU 91 sets the duty stop value DST to the duty command value D(n) (S101). The CPU 91 outputs a PWM control signal indicating the duty command value D(n) set in the process of S101 to the fan circuit 60 (S102). In the fan circuit 60, the DC-DC converter 63 converts the voltage input to the fan circuit 60 into a voltage corresponding to the duty stop value DST as the duty command value D(n) indicated by the PWM control signal. The DC-DC converter 63 applies the converted voltage to the

fan motors

812 and 822 as the fan voltage FV. As a result, the fan voltage FV suddenly drops to the stop voltage. Therefore, the drive of

fan motors

812 and 822 is stopped.

The CPU 91 outputs an enable signal indicating "L" to the fan circuit 60 (S103). As a result, the DC-DC converter 63 changes from an active state to an inactive state. The CPU 91 outputs an activation signal indicating "L" to the fan circuit 60 (S104). As a result, the ON/OFF switch 61 changes from the energized state to the de-energized state. The CPU 91 returns the process to S12.

As explained above, the CPU 91 changes the calculation result "D(n-1)-DD" to the duty command value D(n) in the process of S54 until the duty variation amount DD reaches the predetermined value "1". Set periodically. The duty change amount DD indicates the result of proportional calculation based on the difference between the duty command value D(n-1) and the duty target set value DTGT. The calculation result "D(n-1)-DD" means that the duty change amount DD is calculated with respect to the duty command value D(n-1) so that the duty command value D(n-1) approaches the duty target setting value DTGT. Shows the subtracted result. According to this, the duty command value D(n) is unlikely to drop suddenly, so the fan voltage FV is unlikely to rise suddenly. Therefore, the CPU 91 contributes to the advantage of suppressing the generation of rush current.

As a method of controlling the fan voltage FV, a method of controlling the fan voltage FV using PI (proportional/integral) control may be considered. In this case, the control load on the microcomputer 90 due to the calculation of the integral term increases. Therefore, if the computing power of the microcomputer 90 is low, problems may occur in other controls by the microcomputer 90. For this reason, the method of PI (proportional/integral) control of the fan voltage FV may require a microcomputer 90 with high processing capacity. Furthermore, a method of processing the residual deviation using a past integral term is also conceivable. In this case as well, it is necessary for the microcomputer 90 to calculate the integral term. Furthermore, since the calculated integral term is stored, the storage area of the microcomputer 90 may be occupied. Therefore, even with the method of processing the residual deviation using past integral terms, a microcomputer 90 with high processing capacity may be required.

When the duty variation amount DD reaches the predetermined value "1", the CPU 91 calculates the calculation result "(D(n-1)" in the process of S74 until the duty command value D(n) reaches the duty target set value DTGT. -1)" is periodically set as the duty command value D(n). According to this, the predetermined value is subtracted without calculating the integral term, so the calculation by the CPU 91 is simplified. Therefore, the CPU 91 contributes to the advantage of reducing the control load on the microcomputer 90. Thereby, the CPU 91 contributes to the advantage of reducing the possibility that the microcomputer 90 with high processing capacity is required.

A graph L11 in which the duty command value D(n) is plotted against the passage of time shows the duty ratio from time T0 when the process of S25 is performed to time T1 when the duty change amount DD becomes less than "1" in the process of S53. The curve becomes asymptotic from the stop value DST to the duty target set value DTGT. According to this, a sudden rise in fan voltage FV is suppressed. Therefore, the CPU 91 contributes to the advantage of suppressing the generation of rush current.

The CPU 91 performs the process of S74 once every time the process of S73 is performed twice. In the process of S73, the duty command value D(n) does not change from the duty command value D(n-1). Therefore, the CPU 91 contributes to the advantage of suppressing the generation of rush current due to sudden changes in the duty command value D(n).

The connection terminal 201 has a current upper limit value determined by the standard. By suppressing the generation of rush current, the CPU 91 contributes to the advantage of suppressing a current exceeding the current upper limit value from flowing through the connection terminal 201.

The

fan motors

812 and 822 may be driven in a state where there is a limit to the power supplied from the external power source. In this case, if the total power consumption [W] of the

fan motors

812, 822 based on the duty command value D(n) is larger than the power [W] received by the connection terminal 201, the

fan motors

812, 822 cannot be driven. Problems may occur. In this embodiment, the total power consumption [W] of the

fan motors

812 and 822 based on the duty command value D(n) is smaller than the power [W] received by the connection terminal 201. Therefore, the CPU 91 contributes to the advantage of suppressing irregularities in the drive of the

fan motors

812 and 822 even when the

fan motors

812 and 822 are driven in a state where the power supplied from the external power source is limited. do.

The rotational speed of the

fan motors

812, 822 based on the duty command value D(n) is greater than the rotational speed of the

fan motors

812, 822 based on the duty command value D(n-1). Thereby, each time the CPU 91 outputs a PWM control signal indicating the duty command value D(n) to the fan circuit 60 in the process of S62, the rotational speed of the

fan motors

812 and 822 increases continuously. Therefore, the CPU 91 contributes to the advantage of suppressing the generation of gusts of wind from the

fans

813, 813 when the first change instruction is input to the air cleaner 1.

The CPU 91 receives the first changeover instruction via the first changeover switch 8 or the second changeover switch 16 in the processes of S15, S92, and S63. According to this, the user can change the rotational speed of the

fan motors

812 and 822, that is, the strength of the wind blown out from the

air outlets

55 and 56.

For example, among the three or more AD values that constitute the storage target TS, the maximum value or minimum value may be noise. In the processes of S15, S92, and S63, the CPU 91 receives a switching instruction based on the AD value smaller than the maximum value and larger than the minimum value among the three or more AD values forming the storage target TS. According to this, the CPU 91 receives a switching instruction based on the storage target TS from which AD values that may be noise are excluded. Therefore, the CPU 91 contributes to the advantage of accurately detecting the operation of the second changeover switch 16 by the user.

In the processing of S15, S92, and S63, the CPU 91 receives a switching instruction if the number of average values that are equal to or greater than the ON threshold value among the plurality of average values stored in the ring buffer 931 is equal to or greater than the first predetermined number. According to this, the operation of the second changeover switch 16 by the user is detected based on the plurality of average values. Therefore, the CPU 91 contributes to the advantage of accurately detecting the operation of the second changeover switch 16 by the user.

In the above embodiment, the

fan motors

812 and 822 correspond to the "motor" of the present invention. The fan circuit 60 corresponds to the "voltage control section" of the present invention. The CPU 91 corresponds to the "computer" and "processor" of the present invention. The processes of S13, S62, S82, and S102 correspond to the "output process" of the present invention. The processes of S15, S92, and S63 correspond to the "reception process" of the present invention. The process in S11 corresponds to the "first setting process" of the present invention. The process of S54 corresponds to the "second setting process" of the present invention. The process of S74 corresponds to the "third setting process" of the present invention. The process of S73 corresponds to the "fourth setting process" of the present invention. The connection terminal 201 corresponds to the "terminal" of the present invention. The first changeover switch 8 or the second changeover switch 16 corresponds to the "switch" of the present invention. The processes of S15, S92, and S63 correspond to the "acquisition process" of the present invention.

The present invention may be modified in various ways from the above embodiments. For example, the number of

fan motors

812 and 822 may be one, or three or more. The configuration of the fan circuit 60 is not limited to the above embodiment. In the above embodiment, the air purifier 1 changes when the state of the air purifier 1 is changed from off ST1 to fan small ST2, when the state of the air purifier 1 is changed from fan small ST2 to fan medium ST3, etc. , the rotational speeds of the

fan motors

812 and 822 are increased in stages as the state of the air cleaner 1 changes. On the other hand, the air cleaner 1 may be configured such that the rotational speed of the

fan motors

812 and 822 increases continuously.

The air cleaner 1 increases the rotational speed of the

fan motors

812 and 822 in three stages (small fan ST2, medium fan ST3, and large fan ST4) as the state of the air cleaner 1 changes. On the other hand, the rotational speed of the

fan motors

812 and 822 may be provided in only one or two steps, or may be provided in four or more steps.

In the above embodiment, when the user operates the first changeover switch 8 or the second changeover switch 16, the CPU 91 changes the state of the air purifier 1 from OFF ST1 to fan small ST2, from fan small ST2 to fan medium ST3, etc. do. On the other hand, the CPU 91 may change the state of the air cleaner 1 based on the detection result from the dust sensor 18, for example. More specifically, when the amount of dust detected by the dust sensor 18 exceeds a reference amount, the CPU 91 may change the state of the air cleaner 1 from fan small ST2 to fan medium ST3.

The transition of the state of the air cleaner 1 is not limited to the above embodiment. For example, the state of the air purifier 1 may be switched from large fan ST4 to fan medium ST3 or fan small ST2, or may be switched from fan small ST2 or fan medium ST3 to off ST1, or from off ST1 to fan medium You may switch to ST3 or large fan ST4.

In the above embodiment, the second predetermined number does not need to be more than half of the number of the plurality of storage areas R0 to R10, and may be one, for example. That is, when one average value exceeds a threshold value, the CPU 91 may determine that the switching instruction has been received. When determining whether the CPU 91 has received a switching instruction, the ring buffer 931 may not be used. The method by which the CPU 91 detects the amount of dust may be similarly changed.

The CPU 91 performs the process of S74 once every time the process of S73 is performed twice. On the other hand, the process of S73 may be omitted. That is, when the duty change amount DD reaches the predetermined value "1", the CPU 91 may repeat S74 without performing the process of S73. The CPU 91 may repeat the process of S74 once or multiple times each time the process of S73 is performed once or three or more times.

If the duty change amount DD reaches the predetermined value (S53: NO), the CPU 91 may proceed to the process of S81 without proceeding to the process of S71. The DC-DC converter 63 may apply a higher voltage to the

fan motors

812 and 822 as the duty ratio indicated by the PWM control signal from the CPU 91 is higher. In this case, in the process of S54, the CPU 91 sets the duty command value D(n) to the calculation result "D(n-1)+DD" obtained by adding the duty change amount DD from the duty command value D(n-1). good. Furthermore, in the process of S74, the CPU 91 sets the duty command value D(n) to the calculation result "D(n-1)+1" obtained by adding a predetermined value "1" to the duty command value D(n-1). Bye.

A graph L11 in which the duty command value D(n) is plotted against the passage of time shows the duty ratio from time T0 when the process of S25 is performed to time T1 when the duty change amount DD becomes less than "1" in the process of S53. The curve does not have to be asymptotic from the stop value DST to the duty target setting value DTGT.

The connection terminal 201 does not have to be a terminal defined in the USB TYPE-C (registered trademark) standard, and may be a terminal to which an AC-DC adapter is connected, for example. The connection terminal 201 does not need to have a current upper limit value defined by the standard. Power may be supplied to the air cleaner 1 from a battery. The position where the connection terminal 201 is provided is not limited to the above embodiment.

The predetermined value may be larger than the minimum unit in which the duty command value D(n) can be changed. Error conditions are not limited to the above embodiments. For example, the state of the air cleaner 1 may be changed to error ST5 based on the amount of dust detected by the dust sensor 18.

The method for recovering from error ST5 is to restart the power supply in this embodiment, but press and hold the first changeover switch 8 while the power is on to turn the air purifier 1 into OFF ST1. is also possible.

1 Air purifier 8 First changeover switch 16 Second changeover switch 60 Fan circuit 91 CPU
201

Connection terminal

812, 822

Fan motor

813, 823 Fan

Claims

The air purifier's computer controls the voltage control unit that drives the motor that rotates the fan.
A process of performing PWM control on the voltage control unit, the output process of outputting a PWM control signal indicating a duty ratio to the voltage control unit;
a reception process for receiving an instruction to increase the voltage applied to the motor by the voltage control unit to a target voltage;
a first setting process of setting a target setting value that is the duty ratio according to the target voltage when the instruction is accepted by the reception process;
A second setting that periodically sets the second calculated value to the command value (n) that is the duty ratio indicated by the PWM control signal currently output by the output process until the first calculated value reaches a predetermined value. Execute processing and
The first calculation value is the result of proportional calculation based on the difference between the command value (n-1), which is the duty ratio indicated by the PWM control signal output last time by the output processing, and the target setting value. shows,
The second calculated value indicates a result of adding or subtracting the first calculated value to the command value (n-1) so that the command value (n-1) approaches the target setting value. A voltage control program featuring:
to the computer;
a third setting in which, when the first calculated value reaches the predetermined value, a third calculated value is periodically set to the command value (n) until the command value (n) reaches the target setting value; execute the process,
The third calculated value is characterized in that it indicates a result of adding or subtracting the predetermined value to the command value (n-1) so that the command value (n-1) approaches the target setting value. The voltage control program according to claim 1.
In the second setting process, the second calculated value is set so that a graph in which the command value (n) is plotted over time becomes a curve that asymptotically approaches the target setting value from the reference duty ratio. 2. The voltage control program according to claim 1, wherein the voltage control program is periodically set to the value (n).
to the computer;
When the first calculated value reaches the predetermined value, the command value (n-1) is periodically set to the command value (n) until the command value (n) reaches the target setting value. Execute the fourth setting process,
3. The voltage control program according to claim 2, wherein the third setting process is executed a second predetermined number of times each time the fourth setting process is executed a first predetermined number of times.
with fans,
a motor that rotates the fan;
a voltage control unit for driving the motor;
a processor that controls the voltage control section;
The processor includes:
output processing for outputting a PWM control signal indicating a duty ratio to the voltage control section;
a reception process for receiving an instruction to increase the voltage applied to the motor by the voltage control unit to a target voltage;
a first setting process of setting a target setting value that is the duty ratio according to the target voltage when the instruction is accepted by the reception process;
A second setting that periodically sets the second calculated value to the command value (n) that is the duty ratio indicated by the PWM control signal currently output by the output process until the first calculated value reaches a predetermined value. Execute the process and
The first calculation value is the result of proportional calculation based on the difference between the command value (n-1), which is the duty ratio indicated by the PWM control signal output last time by the output processing, and the target setting value. shows,
The second calculated value indicates a result of adding or subtracting the first calculated value to the command value (n-1) so that the command value (n-1) approaches the target setting value. An air purifier featuring
A terminal that receives power supplied from an external power source and has a current upper limit value determined by the standard,
The air cleaner according to claim 5, wherein the voltage control unit supplies the electric power supplied via the terminal to the motor based on the PWM control signal output by the output processing. Machine.
The processor is characterized in that, in the second setting process, the processor periodically sets the command value (n) such that power consumption based on the command value (n) is smaller than the power received by the terminal. The air cleaner according to claim 6.
In the second setting process, the processor sets the command value (n) such that the rotation speed of the motor based on the command value (n) is larger than the rotation speed of the motor based on the command value (n-1). ) is set periodically. The air cleaner according to any one of claims 5 to 7.
comprising a switch through which the instruction is input by a user's operation;
The air purifier according to any one of claims 5 to 7, wherein the processor receives the instruction via the switch in the reception process.
The switch is a non-contact switch that detects an object located away from the switch and outputs a signal to the processor according to the distance from the switch to the object,
The processor includes:
Executing an acquisition process to acquire the distance according to the signal three or more times,
In the reception process, the instruction is given based on the distance that is smaller than the maximum value and larger than the minimum value among the three or more distances that correspond to the signals acquired three or more times in the acquisition process. The air cleaner according to claim 9, characterized in that it accepts.
The switch is a non-contact switch that detects an object located away from the switch and outputs a signal to the processor according to the distance from the switch to the object,
The processor includes:
Executing an acquisition process to acquire the distance according to the signal multiple times,
10. In the reception process, if the number of distances that are equal to or greater than a predetermined distance among the distances obtained multiple times in the acquisition process is equal to or greater than a predetermined number, the instruction is accepted. Air cleaner.