NZ726726A

NZ726726A - Dehumidifier

Info

Publication number: NZ726726A
Application number: NZ726726A
Authority: NZ
Inventors: Noriyoshi Kabeta; Satoshi Arai; Hiroshi Wakai; Hiroshi Nakamura
Original assignee: Mitsubishi Electric Corp; Mitsubishi Electric Home Appliance Co Ltd
Priority date: 2014-10-01
Filing date: 2015-09-17
Publication date: 2021-04-30
Also published as: JPWO2016052215A1; CN106471726B; HK1231639A1; TWI608197B; WO2016052215A1; TW201632805A; CN106471726A; JP6278127B2

Abstract

In the present invention, a switch switches between direct current bus lines on the output side of a rectifier circuit. A reactor is provided between the positive output side of the rectifier circuit and the positive side of the switch. A smoothing capacitor is connected in parallel with the switch. An inverter converts the bus line voltage to an alternating current voltage to drive a compressor. An inverter controller adjusts the duty factor of the alternating current voltage of the inverter so that the operation frequency of the compressor satisfies a compressor frequency command value. A switch ON time determination unit determines a switch ON time, within a range that is no higher than an upper limit, so as to make the bus line voltage correspond to the output power of the inverter. The lower the compressor frequency command value is, the lower a switch ON time upper limit setting unit sets an upper limit for the switch ON time.

Description

Description Title: DEHUMIDIFIER Field The present invention relates to a difier capable of making operation noise of a reactor less perceptible.

Background Air conditioners use pulse amplitude modulation (PAM) control to control an operation frequency of a compressor with a magnitude of a voltage. A PAM converter switches on/off of a current flowing through a reactor to generate an induction voltage across the reactor, which is used for increasing the voltage (for example, see PTL 1).

Citation List Patent Literature [PTL 1] JPH 9-247943 In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is lly for the e of providing a context for discussing the features of the invention. Unless specifically stated ise, reference to such external documents is not to be ued as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

Summary Technical Problem For an air conditioner, a reactor is provided in an outdoor unit, and operation noise of the reactor causes no problems. On the other hand, for a dehumidifier, a reactor is provided in a housing placed in a room, which causes a problem that operation noise of the reactor is perceptible.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a dehumidifier capable of making operation noise of a reactor less perceptible. An additional or alternative object of the present invention is to at least provide the public with a useful .

Solution to Problem A difier according to a first aspect of the t invention es: a dehumidifier housing; a blower sucking indoor air into the difier housing and generating an airflow for discharging dry air; a dehumidification unit including a compressor compressing a refrigerant, the dehumidification unit using the refrigerant to remove moisture contained in the indoor air and generate the dry air; and a l unit provided in the dehumidifier housing and controlling the blower and the dehumidification unit, wherein the control unit includes: a singlephase AC rectifier circuit rectifying a voltage of an AC source; a switch performing switching between DC buses on an output side of the rectifier circuit; a reactor ted between a positive output side of the rectifier circuit and a positive side of the switch; a smoothing tor connected in parallel with the switch; a rectifier diode including an anode connected to the positive side of the switch and a cathode connected to a positive side of the smoothing tor; an inverter converting a bus voltage between the positive side and a negative side of the smoothing capacitor into an AC voltage to drive the compressor; an operation rank determination unit determining an ion rank based on setting conditions and outputting a compressor frequency instruction value corresponding to the ined operation rank; an inverter control unit adjusting a duty factor of the AC voltage of the er so that an operation frequency of the compressor satisfies the compressor frequency instruction value; a switch ON time determination unit determining an ON time of the switch within a range not higher than an upper limit value so that the bus voltage is a voltage corresponding to an output power of the inverter; a switch ON time upper limit value setting unit setting the upper limit value lower for the compressor frequency instruction value being lower; and a switch control unit controlling the switch in the ON time determined by the switch ON time determination unit in synchronization with a power synchronization signal generated from a voltage of the AC source.

A dehumidifier according to a second aspect of the present invention includes: a dehumidifier housing; a blower sucking indoor air into the dehumidifier housing and generating an airflow for discharging dry air a dehumidification unit ing a compressor compressing a refrigerant, the dehumidification unit using the refrigerant to remove moisture contained in the indoor air and generate the dry air; and a control unit provided in the difier housing and controlling the blower and the dification unit, wherein the control unit includes: a singlephase AC rectifier circuit rectifying a voltage of an AC source; a switch performing switching between DC buses on an output side of the rectifier t; a reactor connected between a positive output side of the rectifier circuit and a positive side of the switch; a smoothing capacitor connected in parallel with the ; a rectifier diode including an anode connected to the positive side of the switch and a cathode connected to a positive side of the ing capacitor; an inverter converting a bus voltage n the positive side and a negative side of the smoothing capacitor into an AC voltage to drive the compressor; an operation rank determination unit determining an operation rank based on setting conditions and outputting a blower rotation speed instruction value corresponding to the determined operation rank; a blower driving unit driving the blower so that a rotation speed of the blower ies the blower rotation speed ction value; a switch ON time determination unit ining an ON time of the switch within a range not higher than an upper limit value so that the rotation speed of the blower satisfies the blower rotation speed instruction value; a switch ON time upper limit value g unit setting the upper limit value lower for the blower rotation speed instruction value being lower; and a switch l unit controlling the switch in the ON time determined by the switch ON time determination unit in onization with a power synchronization signal generated from a voltage of the AC source.

Advantageous Effects of Invention In the present invention, a lower upper limit value of the ON time of the switch is set for a lower compressor frequency instruction value. This can make the operation noise of the reactor less perceptible even if the running noise of the compressor and the blower is low.

Brief Description of the Drawings Fig. 1 is a sectional view of a dehumidifier according to an embodiment of the present invention.

Fig. 2 is a block diagram of the dehumidifier according to the embodiment of the present invention.

Fig. 3 is a perspective view of the dehumidification unit according to the embodiment of the present invention.

Fig. 4 is a block diagram of the dehumidification unit according to the embodiment of the t invention.

Fig. 5 is a block diagram of the control unit according to the embodiment of the present invention.

Fig. 6 shows the ON time of the switch with respect to the operation frequency of the compressor according to the embodiment of the present invention.

Fig. 7 shows the upper limit value of the ON time of the switch with respect to the operation frequency of the compressor according to the embodiment of the present invention.

Fig. 8 shows operation noise of a reactor with respect to an operation ncy of a compressor of a difier according to a comparative e.

Fig. 9 shows ion noise of the reactor with t to the operation ncy of the compressor of the dehumidifier ing to the embodiment of the present invention.

Description of Embodiments Fig. 1 is a sectional view of a dehumidifier according to an embodiment of the present invention. Fig. 2 is a block diagram of the dehumidifier according to the embodiment of the present invention. A difier housing 1 is configured to be self-supportable. A blower 2 sucks indoor air A from an inlet 3 into the dehumidifier housing 1, and generates an airflow for discharging dry air B out of an outlet 4 into a room. The blower 2 has a blower fan and a fan motor for rotating the blower fan.

A dehumidification unit 5 uses a refrigerant to remove moisture contained in the indoor air A and generate the dry air B. A water e tank 6 is removably attached to the dehumidifier housing 1, and stores the moisture removed from the indoor air A.

An operation unit 7 is provided on an upper surface of the dehumidifier housing 1. The operation unit 7 has a power switch of the dehumidifier, a selection portion for selecting an ion mode, and an input portion for a user to input a desired set humidity. A humidity sensor 8, a temperature sensor 9, and a control unit 10 are provided in the dehumidifier housing 1.

The humidity sensor 8 detects a humidity of the indoor air A, and the temperature sensor 9 detects a temperature of the indoor air A. When the power switch of the operation unit 7 is turned on and the control unit 10 detects that a dehumidification mode is selected as an operation mode, the control unit 10 controls the blower 2 and the dehumidification unit 5 so that the humidity of the indoor air is the set humidity.

Fig. 3 is a perspective view of the dehumidification unit according to the embodiment of the present invention. Fig. 4 is a block diagram of the dehumidification unit according to the embodiment of the present invention. A compressor 11, a condenser 12, a decompression device 13, and an evaporator 14 are sequentially ted by a pipe to constitute a refrigerant circuit. The compressor 11 is driven and thus a refrigerant is circulated in the refrigerant t.

Specifically, the compressor 11 first compresses the refrigerant. Then, the condenser 12 cools the refrigerant compressed by the compressor 11. Then, the ression device 13 reduces pressure of and s the refrigerant cooled by the condenser 12. Then, the evaporator 14 absorbs heat from the refrigerant d in pressure and ed by the decompression device 13 to condense and remove moisture contained in the indoor air A. The decompression device 13 is a capillary tube here, but not limited to this, any other decompression device may be used.

Fig. 5 is a block m of the l unit according to the ment of the present invention. A single-phase AC ier circuit 15 rectifies a voltage of an AC source 16. In the embodiment of the present invention, a full-wave rectifier circuit is used as the rectifier circuit 15, but not limited to this, a voltage-doubler rectifier circuit or the like may be selectably used. A switch 17 performs switching n DC buses on an output side of the rectifier circuit 15. A reactor 18 is connected between a ve output side of the ier circuit 15 and a positive side of the switch 17. A smoothing capacitor 19 is connected in parallel with the switch 17.

An anode of a rectifier diode 20 is connected to a positive side of the switch 17, and a cathode is connected to a positive side of the smoothing capacitor 19. An inverter 21 converts a bus voltage that is a DC voltage between the positive side and a negative side of the smoothing capacitor 19 into an AC voltage of any voltage, frequency, and phase to drive the compressor 11.

When an operation rank determination unit 22 detects that the dehumidification mode is selected as the operation mode, the ion rank determination unit 22 determines an operation rank based on setting ions such as a set humidity, a ty detected by the humidity sensor 8, and a ature detected by the temperature sensor 9. For e, the operation rank is higher for a larger difference between the set humidity and the detected humidity. Then, the operation rank determination unit 22 outputs a compressor frequency instruction value and a blower rotation speed instruction value corresponding to the determined operation rank.

A blower driving unit 23 drives the blower 2 so that a rotation speed of the blower 2 satisfies the blower rotation speed instruction value. An inverter control unit 24 adjusts a duty factor of the AC voltage of the inverter 21 so that an operation frequency of the ssor 11 satisfies the compressor ncy instruction value.

Here, the compressor frequency instruction value is a target operation frequency (Hz) of the compressor 11, and the blower rotation speed instruction value is a target rotation speed (rpm) of the blower 2. The compressor frequency instruction value and the blower rotation speed instruction value are ined for each operation rank, and for a higher operation rank, the compressor frequency instruction value and the blower rotation speed instruction value corresponding thereto are higher. For a higher operation frequency of the compressor 11 and a higher rotation speed of the blower 2, the dehumidifier has a higher dehumidification capability.

Table 1 below shows examples of operation ranks, and ssor frequency instruction values and blower rotation speed instruction values ponding thereto.

[Table 1] OPERATION RANK １２３４５ SSOR NCY 30Hz 40Hz 50Hz 60Hz 70Hz INSTRUCTION VALUE BLOWER ROTATION SPEED 300rpm 400rpm 500rpm 600rpm 700rpm INSTRUCTION VALUE An inverter control unit 24 calculates output power of the inverter 21 from an output current of the inverter 21 and outputs the output power as a power signal. A e detection unit 25 detects a bus e between the positive side and the negative side of the smoothing capacitor 19. A switch ON time determination unit 26 determines an ON time of the switch 17 within a range not higher than an upper limit value so that the bus voltage is a voltage corresponding to the output power of the inverter 21 (for example, 285 V). A switch ON time upper limit value setting unit 27 sets the upper limit value of the ON time of the switch 17 based on the compressor frequency instruction value. A switch control unit 28 controls the switch 17 in the ON time determined by the switch ON time determination unit 26 in synchronization with a power synchronization signal generated from the voltage of the AC source 16.

The reactor 18 includes a coil wound around a core of a magnetic material. The core is provided with a gap for adjusting magnetic permeability, and when an AC current is passed h the reactor 18, the core expands and contracts at the gap in proportion to a magnitude of the current (magnetostriction phenomenon). The expansion and contraction vibrates air to generate operation noise of the reactor 18. For a longer ON time of the switch 17, a larger current flows h the reactor 18 to te louder operation noise.

For a high operation frequency of the compressor 11 and a high rotation speed of the blower 2, running noise of the compressor 11 and the blower 2 is high, which makes the operation noise of the reactor 18 less perceptible. On the other hand, when the running noise of the compressor 11 and the blower 2 is low, the operation noise of the reactor 18 is perceptible.

Thus, the switch ON time upper limit value setting unit 27 sets a lower upper limit value of the ON time of the switch 17 for a lower compressor ncy instruction value. This can make the operation noise of the reactor 18 less perceptible even if the running noise of the compressor 11 and the blower 2 is low. Lowering the upper limit value of the ON time of the switch 17 reduces the bus voltage input to the inverter 21. Thus, the inverter control unit 24 ses the duty factor of the output of the inverter 21 by a ent of the bus voltage to keep power ed for operation of the compressor 11. As a variant of this embodiment, the switch ON time determination unit 26 may determine the ON time of the switch 17 within a range not higher than the upper limit value so that the rotation speed of the blower 2 satisfies the blower rotation speed instruction value, and the switch ON time upper limit value setting unit 27 may set a lower upper limit value for a lower blower on speed instruction value.

Fig. 6 shows the ON time of the switch with respect to the operation ncy of the compressor according to the embodiment of the present invention. A higher operation ncy of the compressor consumes higher power, and the ON time of the switch 17 must be increased in order to keep the bus voltage. Also, when the voltage input from the AC source 16 is 90 V as compared to 100 V, the ON time of the switch 17 must be more increased in order to obtain a required bus e.

Fig. 7 shows the upper limit value of the ON time of the switch with respect to the operation frequency of the compressor according to the embodiment of the present invention. A short switch ON time is set for a low operation frequency, and a long switch ON time is set for a high operation frequency. Fig. 8 shows operation noise of a r with respect to an operation frequency of a compressor of a dehumidifier according to a comparative example. The comparative example has no upper limit value of an ON time of a switch 17. Fig. 9 shows operation noise of the reactor with respect to the operation frequency of the compressor of the dehumidifier according to the ment of the present invention. In this embodiment as compared to the comparative example, the operation noise of the reactor 18 is low when the voltage of the AC source 16 is 90 V and the operation frequency of the compressor 11 is 30 to 40 Hz. Thus, when the running noise of the compressor 11 and the blower 2 is low, the operation noise of the reactor 18 can be made less perceptible.

The term ‘comprising’ as used in this specification and claims means ‘consisting at least in part of’. When interpreting statements in this specification and claims which include the term ising’, other features besides the features prefaced by this term in each statement can also be present. Related terms such as ise’ and ‘comprised’ are to be interpreted in a r manner.

Reference Signs List 1 difier housing; 2 ; 5 dehumidification unit; 10 control unit; 11 compressor; 12 condenser; 13 decompression device; 14 evaporator; 16 blower; 15 rectifier circuit; 17 switch; 18 reactor; 19 smoothing capacitor; 20 rectifier diode; 21 inverter; 22 operation rank determination unit; 23 blower driving unit; 24 inverter control unit; 26 switch ON time determination unit; 27 switch ON time upper limit value setting unit; 28 switch control unit

Claims

[Claim 1] A dehumidifier comprising: a dehumidifier housing; a blower sucking indoor air into the difier housing and generating an airflow for discharging dry air; a dehumidification unit ing a compressor compressing a refrigerant, the dehumidification unit using the refrigerant to remove re ned in the indoor air and generate the dry air; and a control unit provided in the dehumidifier housing and controlling the blower and the dehumidification unit, wherein the control unit includes: a single-phase AC rectifier circuit rectifying a voltage of an AC ; a switch performing switching between DC buses on an output side of the rectifier circuit; a reactor connected between a positive output side of the rectifier circuit and a positive side of the switch; a smoothing capacitor connected in parallel with the ; a rectifier diode including an anode connected to the positive side of the switch and a cathode connected to a positive side of the smoothing capacitor; an inverter converting a bus voltage between the positive side and a negative side of the smoothing capacitor into an AC voltage to drive the compressor; an operation rank determination unit determining an operation rank based on setting conditions and outputting a compressor frequency ction value corresponding to the ined operation rank; an er control unit adjusting a duty factor of the AC voltage of the inverter so that an operation ncy of the compressor satisfies the compressor frequency instruction value; a switch ON time determination unit determining an ON time of the switch within a range not higher than an upper limit value so that the bus voltage is a voltage corresponding to an output power of the inverter; a switch ON time upper limit value setting unit setting the upper limit value lower for the compressor frequency instruction value being lower; and a switch l unit controlling the switch in the ON time ined by the switch ON time determination unit in synchronization with a power synchronization signal generated from a voltage of the AC .
[Claim 2] The dehumidifier according to claim 1, wherein the operation rank determination unit outputs a blower rotation speed instruction value corresponding to the determined operation rank, and the control unit includes a blower driving unit driving the blower so that a rotation speed of the blower satisfies the blower rotation speed instruction value.
[Claim 3] A dehumidifier comprising: a dehumidifier housing; a blower sucking indoor air into the dehumidifier g and generating an w for discharging dry air; a dehumidification unit including a compressor compressing a refrigerant, the dehumidification unit using the refrigerant to remove moisture contained in the indoor air and generate the dry air; and a control unit provided in the difier housing and controlling the blower and the dehumidification unit, wherein the control unit includes: a single-phase AC rectifier t rectifying a voltage of an AC source; a switch performing switching between DC buses on an output side of the rectifier circuit; a reactor connected between a positive output side of the rectifier circuit and a ve side of the switch; a smoothing capacitor connected in parallel with the switch; a rectifier diode including an anode connected to the positive side of the switch and a cathode connected to a positive side of the smoothing capacitor; an inverter converting a bus voltage n the positive side and a negative side of the smoothing capacitor into an AC voltage to drive the compressor; an ion rank determination unit determining an operation rank based on setting conditions and outputting a blower rotation speed instruction value corresponding to the determined ion rank; a blower driving unit driving the blower so that a rotation speed of the blower satisfies the blower rotation speed instruction value; a switch ON time determination unit determining an ON time of the switch within a range not higher than an upper limit value so that the rotation speed of the blower satisfies the blower rotation speed instruction value; a switch ON time upper limit value g unit setting the upper limit value lower for the blower rotation speed instruction value being lower; and a switch control unit controlling the switch in the ON time determined by the switch ON time determination unit in synchronization with a power synchronization signal generated from a voltage of the AC source.