CN109386961B - Electric heater protection device, air conditioning unit and electric heater protection method of air conditioning unit - Google Patents

Electric heater protection device, air conditioning unit and electric heater protection method of air conditioning unit Download PDF

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Publication number
CN109386961B
CN109386961B CN201811159108.XA CN201811159108A CN109386961B CN 109386961 B CN109386961 B CN 109386961B CN 201811159108 A CN201811159108 A CN 201811159108A CN 109386961 B CN109386961 B CN 109386961B
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China
Prior art keywords
electric heater
fuse
main board
temperature
disconnected
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CN201811159108.XA
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Chinese (zh)
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CN109386961A (en
Inventor
邓杏珍
宋俊义
成伟
吴斌
林肖纯
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H3/00—Air heaters
    • F24H3/02—Air heaters with forced circulation
    • F24H3/04—Air heaters with forced circulation the air being in direct contact with the heating medium, e.g. electric heating element
    • F24H3/0405—Air heaters with forced circulation the air being in direct contact with the heating medium, e.g. electric heating element using electric energy supply, e.g. the heating medium being a resistive element; Heating by direct contact, i.e. with resistive elements, electrodes and fins being bonded together without additional element in-between
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/18—Arrangement or mounting of grates or heating means
    • F24H9/1809—Arrangement or mounting of grates or heating means for water heaters
    • F24H9/1818—Arrangement or mounting of electric heating means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/20—Arrangement or mounting of control or safety devices
    • F24H9/2007—Arrangement or mounting of control or safety devices for water heaters
    • F24H9/2014—Arrangement or mounting of control or safety devices for water heaters using electrical energy supply
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Resistance Heating (AREA)

Abstract

The invention discloses an electric heater protection device, an air conditioning unit and an electric heater protection method thereof, wherein the device comprises: the fuse and the temperature limiter are arranged on a main loop of the electric heater; the control switch is used for controlling the power-on or power-off of the main loop of the electric heater according to the control signal output by the main board; the main board is respectively connected with the control switch and the optical coupler and is used for outputting control signals to the control switch; or under the condition that the electric heater does not work normally, if the low-level signal output by the optical coupler due to conduction is detected, a first prompt message for controlling the switch to be in fault is sent out. The scheme of the invention can solve the problem that the main circuit of the electric heater can not be effectively disconnected by the temperature limiter and the fuse link at the same time, and the on-off of the electric heater can be detected to have low protection reliability, so that the effect of improving the protection reliability is achieved.

Description

Electric heater protection device, air conditioning unit and electric heater protection method of air conditioning unit
Technical Field
The invention belongs to the technical field of air conditioners, and particularly relates to an electric heater protection device, an air conditioning unit (such as an air conditioning constant temperature and humidity unit) and an electric heater protection method thereof, in particular to a safe and reliable electric heater protection device, an air conditioning unit with the device and an electric heater protection method of the air conditioning unit.
Background
The constant temperature and humidity machine in the air conditioning unit has high requirements on temperature and humidity, and the electric heater needs to be turned on under the conditions of refrigeration and heating, so that the protection mode and whether the unit can judge whether the electric heater is turned off are very important. The electric heater protection mode adopted by the current unit is as follows: the unit uses a temperature limiter to be connected in series on a 12V control loop, a fuse link is connected in series on a main loop, and a main board carries out temperature limiting protection by detecting the on-off of the temperature limiter; the other is: the temperature limiter and the fuse link of the unit are connected in series on the main loop, and the 12V control detection interface is short-circuited.
However, both protection methods have drawbacks, and these two problems cannot be solved at the same time: the temperature limiter and the fuse link can effectively break the main loop of the electric heater and detect the on-off state of the electric heater.
Disclosure of Invention
The invention aims to overcome the defects, and provides an electric heater protection device, an air conditioning unit and an electric heater protection method thereof, so as to solve the problem that the prior art cannot realize that both a temperature limiter and a fuse link can effectively disconnect a main loop of an electric heater and detect the on-off state of the electric heater, so that the protection reliability is low, and achieve the effect of improving the protection reliability.
The invention provides an electric heater protection device, comprising: the device comprises a fuse, a temperature limiter, a control switch, a main board and an optical coupler; the fuse and the temperature limiter are arranged on a main loop of the electric heater; the control switch is used for controlling the power-on or power-off of the main loop of the electric heater according to the control signal output by the main board; the first signal input end of the optical coupler is connected to the first input interface of the main board, the second signal input end of the optical coupler is connected to the second input interface of the main board, and the signal output end of the optical coupler is connected to the IO port of the main board; the main board is respectively connected with the control switch and the optocoupler and is used for outputting the control signal to the control switch; or under the condition that the electric heater does not work normally, if the low-level signal output by the optical coupler due to conduction is detected, a first prompt message for controlling the switch to be in fault is sent out.
Optionally, the method further comprises: a first connection line and a second connection line; the first connecting wire is arranged between the first connecting end of the electric heater and the first input interface of the main board; the second connecting wire is arranged between the second connecting end of the electric heater and the second input interface of the main board; the main board is also used for determining that the main loop of the electric heater works normally if the optical coupler is detected to be on; and if the optical coupler is detected to be not conducted, determining that the fuse and/or the temperature limiter are/is disconnected.
Optionally, the main board determines that the fuse and/or the temperature limiter are disconnected, including: if the duration time of the non-conduction of the optocoupler is longer than the set duration time, determining that the fuse is disconnected, and initiating a second prompting message of the disconnection of the fuse; or if the duration of non-conduction of the optocoupler is smaller than or equal to the set duration, determining that the temperature limiter is disconnected and the fuse is not disconnected.
Optionally, the fuse and the temperature limiter are both arranged on a live wire of an alternating current power supply of the electric heater, and the temperature limiter is arranged between the fuse and the electric heater; the fuse is used for performing first over-temperature protection based on a first set temperature on a main loop of the electric heater; and/or the temperature limiter is used for performing second over-temperature protection based on a second set temperature on a main circuit of the electric heater; the second set temperature is less than the first set temperature.
Optionally, the control switch includes: an alternating current contactor; the normally open contact of the alternating current contactor is arranged on the main loop of the electric heater; the electromagnetic coil of the alternating current contactor is arranged between the alternating current power supply of the main board and the control signal output interface of the main board.
Optionally, the control switch failure includes: and normally open contacts of the alternating current contactor are adhered.
Optionally, the optocoupler is disposed on the motherboard.
In accordance with another aspect of the present invention, there is provided an air conditioning unit comprising: the electric heater protection device is described above.
In accordance with another aspect of the present invention, in combination with the above-mentioned air conditioning unit, an electric heater protection method for an air conditioning unit is provided, including: the main loop of the electric heater is controlled to be electrified or powered off according to a control signal output by the main board through the control switch; outputting the control signal to the control switch; or under the condition that the electric heater does not work normally, if the main board for outputting the control signal detects a low-level signal output by the optical coupler connected to the main board due to conduction, a first prompt message of the control switch fault is sent out.
Optionally, the method further comprises: connecting the optocoupler to two ends of the electric heater; if the optical coupler is detected to be conducted, determining that a main loop of the electric heater works normally; or if the optical coupler is detected to be not conducted, determining that the fuse and/or the temperature limiter are/is disconnected.
Optionally, determining that the fuse and/or the temperature limiter are open includes: if the duration time of the non-conduction of the optocoupler is longer than the set duration time, determining that the fuse is disconnected, and initiating a second prompting message of the disconnection of the fuse; or if the duration of non-conduction of the optocoupler is smaller than or equal to the set duration, determining that the temperature limiter is disconnected and the fuse is not disconnected.
Optionally, the method further comprises: the main circuit of the electric heater is subjected to first over-temperature protection based on a first set temperature through a fuse; and/or, through the temperature limiter, performing a second over-temperature protection based on a second set temperature on the main circuit of the electric heater; the second set temperature is less than the first set temperature.
According to the scheme of the invention, the main circuit of the electric heater can be effectively disconnected by utilizing the temperature limiter and/or the fuse link, so that the main circuit of the electric heater of the air conditioning unit can be disconnected by temperature limiting protection under the conditions that the contacts of the electric heater of the air conditioning unit are adhered and the air conditioning unit is not dry-burned, the danger is avoided, the fuse link is not fused, the maintenance and replacement of the electric heater are reduced, the service life is prolonged, and the protection reliability is also improved.
Furthermore, the scheme of the invention can detect the on-off state of the electric heater, judge whether the electric heater is protected by temperature limitation or is permanently disconnected, and realize that a user or after-sale can check faults to judge whether the electric heater is disconnected by temperature limitation or is permanently disconnected, thereby being convenient after-sale and being beneficial to improving the reliability and the safety of the protection.
Further, according to the scheme, when the contact points of the contactor are adhered, the main circuit of the electric heater can be disconnected through temperature limiting protection; whether the electric heater is disconnected can be effectively detected, whether the fuse link is disconnected or not can be deduced according to the time length to report faults, the reliability and the safety of the protection of the electric heater are improved, and the service life of the electric heater is prolonged.
Therefore, according to the scheme of the invention, the temperature limiter is connected to the main circuit of the electric heater, and meanwhile, the optocoupler detection is added on the main board of the electric heater, so that the main circuit of the electric heater can be effectively disconnected through the temperature limiter and/or the fuse link, and the on-off state of the electric heater can be detected, and the temperature limiting protection or the permanent disconnection protection can be judged; the problem that the protection reliability is low due to the fact that the temperature limiter and the fuse link can not be used for effectively breaking the main loop of the electric heater and detecting the on-off state of the electric heater simultaneously in the prior art is solved, and therefore the defects of low reliability, poor safety and short service life in the prior art are overcome, and the beneficial effects of high reliability, good safety and long service life are achieved.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is a schematic diagram of an embodiment of an electrical heater protection device according to the present invention;
fig. 2 is a schematic structural diagram of a first technical solution of the protection of an original electric heater;
fig. 3 is a schematic structural diagram of a second technical scheme of the original electric heater protection;
FIG. 4 is a schematic flow chart of an embodiment of an electric heater protection method according to the present invention;
fig. 5 is a flow chart of an embodiment of detecting the on/off of the electric heater in the method of the present invention.
In the embodiment of the present invention, reference numerals are as follows, in combination with the accompanying drawings:
10-a main board; 20-optocouplers; 30-a first connection line; 40-second connection line.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments of the present invention and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
According to an embodiment of the present invention, there is provided an electric heater protection device. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The electric heater protection device may include: a fuse (i.e., fuse FUT), a temperature limiter (i.e., temperature limiter SAT), a control switch, a motherboard 10, and an optocoupler 20.
Wherein the fuse and the temperature limiter are disposed on a main circuit of the electric heater (i.e., electric heater EH).
Optionally, the fuse and the temperature limiter are both arranged on a live wire of an ac power supply of the electric heater, the temperature limiter is arranged between the fuse and the electric heater, the fuse is arranged close to the live wire of the ac power supply, and the electric heater is arranged close to a zero line of the ac power supply.
Specifically, the fuse may be used for performing a first over-temperature protection based on a first set temperature on a main circuit of the electric heater, and the first over-temperature protection is not recoverable. For example: the fuse body FUT is used as overheat protection, and primary fusing is not recoverable.
Specifically, the temperature limiter can be used for performing second over-temperature protection based on a second set temperature on the main circuit of the electric heater, and the second over-temperature protection can be recovered. The second set temperature is less than the first set temperature. For example: the temperature limiter SAT can be recovered as overheat protection and can be repeatedly turned on and off.
Therefore, the fuse and the temperature limiter are connected in the main loop of the electric heater in series, and the fuse is arranged close to the alternating current power supply of the electric heater, so that the safety of over-temperature protection can be improved, the protection reliability of the electric heater can be improved, and the service life of the electric heater can be prolonged.
In an alternative example, the control switch is disposed between the main circuit of the electric heater and the main board, and may be used to control the power on or off of the main circuit of the electric heater according to a control signal output from the main board 10.
Optionally, the control switch may include: an alternating current contactor.
Specifically, the normally open contact of the alternating current contactor is arranged on the main loop of the electric heater and close to the zero line N of the alternating current power supply of the electric heater. The electromagnetic coil of the alternating current contactor is arranged between a zero line N of an alternating current power supply of the main board (10) and a control signal output interface (namely an output interface HEAT of the main board 10) of the main board (10).
For example: the alternating-current contactor K1 is used for controlling the on-off of the electric heater EH.
Therefore, the alternating-current contactor is used as a control switch to control the on-off of the electric heater, so that the control mode is simple and convenient, and the safety is good.
Wherein, the control switch fault may include: and normally open contacts of the alternating current contactor are adhered.
For example: when the contact points of the contactor are adhered, the main circuit of the electric heater can be disconnected through temperature limiting protection.
Another example is: the temperature limiter and the fuse link can effectively disconnect the main circuit of the electric heater, so that the electric heater of the air conditioning unit can disconnect the main circuit of the electric heater through temperature limiting protection under the condition that the contacts of the contactor are adhered, no danger is generated, the fuse link is not fused, and the maintenance and replacement of the electric heater are reduced.
Therefore, when the AC contactor is used as the control switch, the normally open contact of the AC contactor is stuck to determine the fault of the control switch, the judgment mode is simple and convenient, and the reliability of the judgment result is high.
In an alternative example, the first signal input end of the optocoupler 20 is connected to a first input interface of the motherboard 10 (such as the input interface EH1 of the motherboard 10), the second signal input end of the optocoupler 20 is connected to a second input interface of the motherboard 10 (such as the input interface EH2 of the motherboard 10), and the signal output end of the optocoupler 20 is connected to the IO port of the motherboard 10.
For example: the temperature limiter SAT is connected to the main loop of the electric heater EH, and meanwhile, the optocoupler detection is added on the main board.
Optionally, the optocoupler 20 is disposed on the motherboard 10.
Therefore, the optocoupler is arranged on the main board, so that the detection is convenient, the occupied space is small, and the circuit structure is simple.
In an alternative example, the main board 10 is connected to the control switch and the optocoupler 20, respectively, and may be used to output the control signal to the control switch; or, if the electric heater does not work normally (for example, if the air conditioning unit to which the electric heater belongs does not work normally, the fan of the air conditioning unit does not work normally, or the main board 10 does not output at least one of the control signals), if the IO port of the main board 10 detects a low-level signal output by the signal output end of the optocoupler 20 due to conduction, a first prompt message (such as one or more alarm signals or alarm messages including audible and visual, voice, text, etc.) of the control switch fault is sent. For example: the main board 10 may determine whether the control switch is faulty according to the feedback signal of the optocoupler 20, and initiate a prompt message or a prompt signal when the control switch is faulty. For example: the main board can be used for outputting a control signal for controlling the contactor; and receiving the detection signal, performing internal judgment and outputting an alarm signal.
For example: when the fan normally works, under the condition that the fan normally works, the HEAT (namely, the voltage signal of the main board output control contactor K1) of the main board outputs a control signal to enable the contactor K1 to be closed, the electric heater EH normally electrifies and works, the electric heater is over-high in temperature, the temperature limiter SAT effectively breaks a main loop of the electric heater EH in a temperature limiting protection mode, and the fuse link FUT is normal.
For example: when the fan does not normally work, even if the HEAT of the main board does not output a control signal, and contacts of the contactor K1 of the electric heater are controlled to adhere, the electric heater EH is normally electrified to work, the temperature limiter SAT performs temperature limiting protection to effectively disconnect a main loop of the electric heater EH, and the fuse link FUT is normally not fused.
For example: whether the contactor K1 is adhered to the main board or not can be detected, when the fan does not work normally, the HEAT of the main board does not output control signals, and voltage 220V is arranged between the EH2 (namely a second input interface of the main board) and the EH1 (namely a first input interface of the main board) of the main board, so that the optocoupler is conducted, an IO port of a chip of the main board detects low level, and the main board sends out an adhesion protection alarm signal of the contactor.
Therefore, the fuse and the temperature limiter are connected in the main loop of the electric heater in series, the optocoupler is arranged at the main board, and if the optocoupler is detected to be conducted under the condition that the electric heater does not work normally, the fault of the control switch is determined, so that the reliability and the safety of the protection of the electric heater are improved.
In an alternative embodiment, the method may further include: a first connection line 30 and a second connection line 40.
The first connection line 30 is disposed between a first connection end of the electric heater (i.e., an end of the electric heater near the temperature limiter) and a first input interface of the main board 10 on the main circuit of the electric heater. The second connection line 40 is disposed between a second connection end of the electric heater (i.e., an end of the electric heater near the control switch) and a second input interface of the main board 10 on the main circuit of the electric heater.
In an optional example, the main board 10 may be further configured to determine that the main circuit of the electric heater works normally if it is detected through the IO port of the main board 10 that the signal output end of the optocoupler 20 is turned on; if it is detected through the IO port of the motherboard 10 that the signal output end of the optocoupler 20 is not conductive (such as a high level signal output due to non-conductive), it is determined that the fuse and/or the temperature limiter are/is disconnected.
For example: an optical coupler is connected between the temperature limiter of the electric heater and the zero line N by leading a line to the EH1 on the main board, when the HEAT on the main board outputs a control signal, the contact of the contactor K1 is closed, the on-off of the electric heater can be detected, and whether the protection of the temperature limiter SAT or the permanent disconnection protection (FUT disconnection) can be judged.
For example: when the temperature limiter SAT and the fuse body FUT are normal, the whole loop of the electric heater EH is normally conducted, and a voltage 220V and an optical coupler are conducted between the main boards EH2 and EH 1.
For example: when the temperature limiter SAT or the fuse body FUT is disconnected, the whole loop of the electric heater EH is disconnected and does not work, no voltage difference exists between the main boards EH2 and EH1, and the optical coupler is not conducted.
For example: when the temperature limiter SAT is protected, the temperature of the electric heater is rapidly reduced after the temperature limiter SAT is protected, and when the temperature limiter SAT is reduced to the recoverable temperature, the temperature limiter SAT is recovered to be closed, so that the EH2 and the EH1 on the main board are disconnected when the temperature limiter SAT is detected to be disconnected, and the voltage limiter SAT is detected to be disconnected when the temperature limiter SAT is recovered to be closed.
Therefore, the main loop of the electric heater is determined to be normal when the optical coupler is detected to be on, and the main loop of the electric heater is determined to be off when the optical coupler is detected to be off, so that the detection structure is simple, the detection mode is convenient, the protection function of the electric heater is enriched, and the reliability of the protection of the electric heater is also improved.
Optionally, the determining that the fuse and/or the temperature limiter are opened by the motherboard 10 may include: if the duration time of the non-conduction of the optocoupler is longer than the set duration time, determining that the fuse is disconnected, and initiating a second prompting message of the disconnection of the fuse; or if the duration of non-conduction of the optocoupler is smaller than or equal to the set duration, determining that the temperature limiter is disconnected and the fuse is not disconnected.
For example: and whether the electric heater is disconnected can be effectively detected, whether the fuse link is disconnected can be deduced according to the time, and faults are reported. If the on-off state of the electric heater is detected, whether the electric heater is protected by temperature limitation or permanent disconnection can be judged, so that a user or after-sale user can check the fault to judge whether the electric heater is disconnected by temperature limitation or permanent disconnection, and the electric heater is convenient to after-sale.
For example: the optocoupler is protected by the temperature limiter SAT when the optocoupler is conductive and non-conductive.
For example: when fuse-link FUT protection, the fuse-link is unrecoverable, and the main loop of electric heater EH has thoroughly been disconnected, does not have voltage difference for a long time between EH2 and the EH1 on the mainboard, and the optocoupler is non-conductive for a long time, and constant temperature constant humidity unit can't guarantee constant temperature's requirement, has needed to remind the customer to change fuse-link FUT.
Therefore, whether the fuse is disconnected or the temperature limiter is disconnected is judged according to the non-conducting duration of the optical coupler under the condition that the main loop of the electric heater is determined to be disconnected, and a prompt message of the fuse disconnection is initiated under the condition that the fuse is disconnected, so that a user can maintain the electric heater conveniently in time, the maintenance effect is improved, the timeliness and the reliability of the work of the electric heater are restored, and the user experience is improved.
Through a large number of experiments, the technical scheme of the invention can effectively disconnect the main circuit of the electric heater by utilizing the temperature limiter and/or the fuse link, so that the main circuit of the electric heater of the air conditioning unit can be disconnected through temperature limiting protection under the conditions that contacts of the electric heater of the air conditioning unit are adhered and the air conditioning unit is not dry-burned, no danger is generated, the fuse link is not fused, the maintenance and replacement of the electric heater are reduced, the service life is prolonged, and the protection reliability is also improved.
According to an embodiment of the present invention, there is also provided an air conditioning unit corresponding to the electric heater protection device. The air conditioning unit may include: the electric heater protection device is described above.
In an alternative embodiment, the main circuit of the electric heater can be disconnected through temperature limiting protection when the contact points of the contactor are adhered; and whether the electric heater is disconnected can be effectively detected, whether the fuse link is disconnected can be deduced according to the time, and faults are reported.
Optionally, in the scheme of the invention, both the temperature limiter and the fuse link can effectively disconnect the main circuit of the electric heater. Therefore, the electric heater of the air conditioning unit can be disconnected from the main circuit of the electric heater through temperature limiting protection under the condition of contact adhesion of a contactor and non-dry combustion of the unit, the danger is avoided, the fuse link is not fused, and the maintenance and replacement of the electric heater are reduced.
Optionally, in the scheme of the invention, the on-off state of the electric heater can be detected, and whether the protection is temperature limiting protection or permanent off protection can be judged. Therefore, a user or after-sale user can check the fault to judge whether the electric heater is in recoverable temperature limiting disconnection or permanent disconnection, and the after-sale operation is convenient.
In an alternative embodiment, the implementation of the solution of the present invention may be illustrated by way of example with reference to the example shown in fig. 1.
In fig. 1, FUT is a fuse link or fuse, unrecoverable; the SAT is a temperature limiter and can be recovered; EH is an electric heater; k1 is a contactor.
One specific implementation of the solution of the present invention may be seen in the example shown in fig. 1. As shown in fig. 1, the temperature limiter SAT is connected to the main circuit of the electric heater EH, and meanwhile, an optocoupler detection is added on the main board; in the prior art, a temperature limiter SAT is connected to a main loop of an electric heater EH, a main board has no detection interface, and the on-off state of the temperature limiter SAT cannot be known, for example, see an example shown in fig. 3; in the second prior art, the SAT of the middle temperature limiter is connected between +12v and EH1 of the motherboard to be used as on-off detection, for example, when K1 is adhered, the main loop of the electric heater EH cannot be disconnected through the SAT, for example, see an example shown in fig. 2.
In fig. 1, the roles of the components may include: fuse link FUT, as overheat protection, is not recoverable by primary fusing; the temperature limiter SAT is used as overheat protection, can recover and can be repeatedly turned on and off; an electric heater EH, which may be used for a heated device; the alternating-current contactor K1 is used for controlling the on-off of the electric heater EH. The main board can be used for outputting a control signal for controlling the contactor; and receiving the detection signal, performing internal judgment and outputting an alarm signal.
Alternatively, in the example shown in fig. 1, the electric heater uses a temperature limiter and a fuse link in series on the main circuit:
1) When the fan normally works, under the condition that the fan normally works, the HEAT (namely, the voltage signal of the main board output control contactor K1) of the main board outputs a control signal to enable the contactor K1 to be closed, the electric heater EH normally electrifies and works, the electric heater is over-high in temperature, the temperature limiter SAT effectively breaks a main loop of the electric heater EH in a temperature limiting protection mode, and the fuse link FUT is normal.
For example: under the condition that the air conditioning unit is in normal operation and the fan is in normal operation, the reason for temperature limiting protection is probably that the temperature of the electric heater is too high due to unsmooth ventilation caused by the blocking of the air inlet.
2) When the fan does not normally work, even if the HEAT of the main board does not output a control signal, and contacts of the contactor K1 of the electric heater are controlled to adhere, the electric heater EH is normally electrified to work, the temperature limiter SAT performs temperature limiting protection to effectively disconnect a main loop of the electric heater EH, and the fuse link FUT is normally not fused.
3) Whether the contactor K1 is adhered to the main board or not can be detected, when the fan does not work normally, the HEAT of the main board does not output control signals, and voltage 220V is arranged between the EH2 (namely a second input interface of the main board) and the EH1 (namely a first input interface of the main board) of the main board, so that the optocoupler is conducted, an IO port of a chip of the main board detects low level, and the main board sends out an adhesion protection alarm signal of the contactor.
Optionally, in the example shown in fig. 1, on-off of the electric heater can be detected, and it can be determined whether the temperature limiter SAT protection or the permanent off protection (FUT off):
leading a line to the EH1 on the main board at the front ends of the temperature limiter and the fuse link of the electric heater, connecting an optical coupler between the line and the zero line N, and closing contacts of the contactor K1 when the HEAT on the main board outputs a control signal:
1) When the temperature limiter SAT and the fuse body FUT are normal, the whole loop of the electric heater EH is normally conducted, and a voltage 220V and an optical coupler are conducted between the main boards EH2 and EH 1.
2) When the temperature limiter SAT or the fuse body FUT is disconnected, the whole loop of the electric heater EH is disconnected and does not work, no voltage difference exists between the main boards EH2 and EH1, and the optical coupler is not conducted.
3) When the temperature limiter SAT is protected, the temperature of the electric heater is rapidly reduced after the temperature limiter SAT is protected, and when the temperature limiter SAT is reduced to the recoverable temperature, the temperature limiter SAT is recovered to be closed, so that the EH2 and the EH1 on the main board are disconnected when the temperature limiter SAT is detected to be disconnected, and the voltage limiter SAT is detected to be disconnected when the temperature limiter SAT is recovered to be closed; so that the optocoupler is protected by the temperature limiter SAT when it is conductive and when it is non-conductive.
4) When fuse-link FUT protection, the fuse-link is unrecoverable, and the main loop of electric heater EH has thoroughly been disconnected, does not have voltage difference for a long time between EH2 and the EH1 on the mainboard, and the optocoupler is non-conductive for a long time, and constant temperature constant humidity unit can't guarantee constant temperature's requirement, has needed to remind the customer to change fuse-link FUT.
Since the processing and the functions implemented by the air conditioning unit of the present embodiment basically correspond to the embodiment, the principle and the example of the apparatus shown in fig. 1, the description of the present embodiment is not exhaustive, and reference may be made to the related description of the foregoing embodiment, which is not repeated herein.
Through a large number of tests, the technical scheme of the invention can detect the on-off state of the electric heater, judge whether the electric heater is protected by limiting temperature or is permanently disconnected, and realize that a user or after-sale user can check faults to judge whether the electric heater is disconnected by limiting temperature or is permanently disconnected, thereby being convenient for after-sale and being beneficial to improving the reliability and safety of protection.
According to an embodiment of the present invention, there is further provided a method for protecting an electric heater of an air conditioning unit, which corresponds to the air conditioning unit, as shown in fig. 4, which is a schematic flow chart of an embodiment of the method of the present invention. The electric heater protection method may include: step S110 to step S130.
At step S110, the main circuit of the electric heater is controlled to be powered on or off according to the control signal output from the main board 10 by a control switch provided between the main circuit of the electric heater and the main board.
At step S120, the control signal is output to the control switch through the main board 10 connected to the control switch and the optocoupler 20, respectively. Or,
at step S130, if the electric heater does not work normally (e.g. if the air conditioning unit to which the electric heater belongs does not work normally, the fan of the air conditioning unit does not work normally, and the main board 10 does not output at least one of the control signals), by setting the optocoupler 20, if the signal output end of the optocoupler 20 connected to the main board 10, which can be used to output the control signal, is detected by the IO port of the main board 10 itself, is a low-level signal output by conduction, then a first prompt message (such as one or more alarm signals or alarm messages of acousto-optic, voice, text, etc.) of the control switch fault is sent. For example: the main board 10 may determine whether the control switch is faulty according to the feedback signal of the optocoupler 20, and initiate a prompt message or a prompt signal when the control switch is faulty.
The first signal input end of the optocoupler 20 is connected to a first input interface of the motherboard 10 (e.g., an input interface EH1 of the motherboard 10), the second signal input end of the optocoupler 20 is connected to a second input interface of the motherboard 10 (e.g., an input interface EH2 of the motherboard 10), and the signal output end of the optocoupler 20 is connected to an IO port of the motherboard 10.
For example: the main board can be used for outputting a control signal for controlling the contactor; and receiving the detection signal, performing internal judgment and outputting an alarm signal.
For example: when the fan normally works, under the condition that the fan normally works, the HEAT (namely, the voltage signal of the main board output control contactor K1) of the main board outputs a control signal to enable the contactor K1 to be closed, the electric heater EH normally electrifies and works, the electric heater is over-high in temperature, the temperature limiter SAT effectively breaks a main loop of the electric heater EH in a temperature limiting protection mode, and the fuse link FUT is normal.
For example: when the fan does not normally work, even if the HEAT of the main board does not output a control signal, and contacts of the contactor K1 of the electric heater are controlled to adhere, the electric heater EH is normally electrified to work, the temperature limiter SAT performs temperature limiting protection to effectively disconnect a main loop of the electric heater EH, and the fuse link FUT is normally not fused.
For example: whether the contactor K1 is adhered to the main board or not can be detected, when the fan does not work normally, the HEAT of the main board does not output control signals, and voltage 220V is arranged between the EH2 (namely a second input interface of the main board) and the EH1 (namely a first input interface of the main board) of the main board, so that the optocoupler is conducted, an IO port of a chip of the main board detects low level, and the main board sends out an adhesion protection alarm signal of the contactor.
Therefore, the fuse and the temperature limiter are connected in the main loop of the electric heater in series, the optocoupler is arranged at the main board, and if the optocoupler is detected to be conducted under the condition that the electric heater does not work normally, the fault of the control switch is determined, so that the reliability and the safety of the protection of the electric heater are improved.
In an alternative embodiment, the method may further include: and detecting the on-off process of the electric heater.
The following is a schematic flow chart of an embodiment of detecting the on/off of the electric heater in the method of the present invention in connection with fig. 5, which further illustrates a specific process of detecting the on/off of the electric heater, and may include: step S210 to step S230.
Step S210, the optocoupler 20 is further connected to two ends of the electric heater. For example: the first connecting wire 30 is disposed between a first connecting end of the electric heater on the main circuit of the electric heater (i.e. an end of the electric heater close to the temperature limiter) and a first input interface of the main board 10, and the second connecting wire 40 is disposed between a second connecting end of the electric heater on the main circuit of the electric heater (i.e. an end of the electric heater close to the control switch) and a second input interface of the main board 10. The method comprises the steps of,
step S220, if it is detected through the IO port of the main board 10 that the signal output end of the optocoupler 20 is turned on, determining that the main circuit of the electric heater works normally. Or,
in step S230, if it is detected through the IO port of the motherboard 10 that the signal output end of the optocoupler 20 is not conductive (e.g., a high level signal output due to non-conductive state), it is determined that the fuse and/or the temperature limiter are/is disconnected.
For example: an optical coupler is connected between the temperature limiter of the electric heater and the zero line N by leading a line to the EH1 on the main board, when the HEAT on the main board outputs a control signal, the contact of the contactor K1 is closed, the on-off of the electric heater can be detected, and whether the protection of the temperature limiter SAT or the permanent disconnection protection (FUT disconnection) can be judged.
For example: when the temperature limiter SAT and the fuse body FUT are normal, the whole loop of the electric heater EH is normally conducted, and a voltage 220V and an optical coupler are conducted between the main boards EH2 and EH 1.
For example: when the temperature limiter SAT or the fuse body FUT is disconnected, the whole loop of the electric heater EH is disconnected and does not work, no voltage difference exists between the main boards EH2 and EH1, and the optical coupler is not conducted.
For example: when the temperature limiter SAT is protected, the temperature of the electric heater is rapidly reduced after the temperature limiter SAT is protected, and when the temperature limiter SAT is reduced to the recoverable temperature, the temperature limiter SAT is recovered to be closed, so that the EH2 and the EH1 on the main board are disconnected when the temperature limiter SAT is detected to be disconnected, and the voltage limiter SAT is detected to be disconnected when the temperature limiter SAT is recovered to be closed.
Therefore, the main loop of the electric heater is determined to be normal when the optical coupler is detected to be on, and the main loop of the electric heater is determined to be off when the optical coupler is detected to be off, so that the detection structure is simple, the detection mode is convenient, the protection function of the electric heater is enriched, and the reliability of the protection of the electric heater is also improved.
Optionally, determining, in step S230, that the fuse and/or the temperature limiter are opened by the motherboard 10 may include: if the duration time of the non-conduction of the optocoupler is longer than the set duration time, determining that the fuse is disconnected, and initiating a second prompting message of the disconnection of the fuse; or if the duration of non-conduction of the optocoupler is smaller than or equal to the set duration, determining that the temperature limiter is disconnected and the fuse is not disconnected.
For example: and whether the electric heater is disconnected can be effectively detected, whether the fuse link is disconnected can be deduced according to the time, and faults are reported. If the on-off state of the electric heater is detected, whether the electric heater is protected by temperature limitation or permanent disconnection can be judged, so that a user or after-sale user can check the fault to judge whether the electric heater is disconnected by temperature limitation or permanent disconnection, and the electric heater is convenient to after-sale.
For example: the optocoupler is protected by the temperature limiter SAT when the optocoupler is conductive and non-conductive.
For example: when fuse-link FUT protection, the fuse-link is unrecoverable, and the main loop of electric heater EH has thoroughly been disconnected, does not have voltage difference for a long time between EH2 and the EH1 on the mainboard, and the optocoupler is non-conductive for a long time, and constant temperature constant humidity unit can't guarantee constant temperature's requirement, has needed to remind the customer to change fuse-link FUT.
Therefore, whether the fuse is disconnected or the temperature limiter is disconnected is judged according to the non-conducting duration of the optical coupler under the condition that the main loop of the electric heater is determined to be disconnected, and a prompt message of the fuse disconnection is initiated under the condition that the fuse is disconnected, so that a user can maintain the electric heater conveniently in time, the maintenance effect is improved, the timeliness and the reliability of the work of the electric heater are restored, and the user experience is improved.
In an alternative embodiment, the method may further include: a first over-temperature protection based on a first set temperature is carried out on a main loop of the electric heater through a fuse, and the first over-temperature protection is unrecoverable; and/or, through the temperature limiter, the main circuit of the electric heater can be used for carrying out second over-temperature protection based on a second set temperature, and the second over-temperature protection can be recovered. The second set temperature is less than the first set temperature.
For example: the fuse body FUT is used as overheat protection, and primary fusing is not recoverable. The temperature limiter SAT can be recovered as overheat protection and can be repeatedly turned on and off.
Therefore, the fuse and the temperature limiter are connected in the main loop of the electric heater in series, and the fuse is arranged close to the alternating current power supply of the electric heater, so that the safety of over-temperature protection can be improved, the protection reliability of the electric heater can be improved, and the service life of the electric heater can be prolonged.
Since the processing and the functions implemented by the method of the present embodiment basically correspond to the embodiments, principles and examples of the air conditioning unit described above, the description of the present embodiment is not exhaustive, and reference may be made to the related descriptions in the foregoing embodiments, which are not repeated herein.
Through a large number of experiments, the technical scheme of the embodiment is adopted, and the main circuit of the electric heater can be disconnected through temperature limiting protection when contacts of the contactor are adhered; whether the electric heater is disconnected can be effectively detected, whether the fuse link is disconnected or not can be deduced according to the time length to report faults, the reliability and the safety of the protection of the electric heater are improved, and the service life of the electric heater is prolonged.
In summary, it is readily understood by those skilled in the art that the above-described advantageous ways can be freely combined and superimposed without conflict.
The above description is only an example of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (11)

1. An electric heater protection device, comprising: the device comprises a fuse, a temperature limiter, a control switch, a main board (10) and an optical coupler (20); the fuse and the temperature limiter are arranged on a main loop of the electric heater; wherein,,
the control switch is used for controlling the power-on or power-off of the main loop of the electric heater according to the control signal output by the main board (10);
the first signal input end of the optical coupler (20) is connected to the first input interface of the main board (10), the second signal input end of the optical coupler (20) is connected to the second input interface of the main board (10), and the signal output end of the optical coupler (20) is connected to the IO port of the main board (10);
the main board (10) is respectively connected with the control switch and the optocoupler (20) and is used for outputting the control signal to the control switch; or under the condition that the electric heater does not work normally, if a low-level signal output by the optical coupler (20) due to conduction is detected, a first prompt message of the control switch fault is sent out;
further comprises: a first connection line (30) and a second connection line (40); wherein the first connecting wire (30) is arranged between the first connecting end of the electric heater and the first input interface of the main board (10); the second connecting wire (40) is arranged between the second connecting end of the electric heater and the second input interface of the main board (10); the main board (10) is further used for determining that the main loop of the electric heater works normally if the optical coupler (20) is detected to be conducted; if the optocoupler (20) is detected to be not conducted, the fuse and/or the temperature limiter are/is determined to be disconnected;
wherein the main board (10) determines that the fuse and/or the temperature limiter are/is disconnected, comprising: if the duration time of the non-conduction of the optocoupler is longer than the set duration time, determining that the fuse is disconnected, and initiating a second prompting message of the disconnection of the fuse; or if the duration of non-conduction of the optocoupler is smaller than or equal to the set duration, determining that the temperature limiter is disconnected and the fuse is not disconnected.
2. The apparatus of claim 1, wherein the fuse and the temperature limiter are both disposed on a hot line of an ac power source of the electric heater, and the temperature limiter is disposed between the fuse and the electric heater; wherein,,
the fuse is used for performing first over-temperature protection based on a first set temperature on a main loop of the electric heater; and/or the number of the groups of groups,
the temperature limiter is used for performing second over-temperature protection based on a second set temperature on a main loop of the electric heater; the second set temperature is less than the first set temperature.
3. The apparatus according to claim 1 or 2, wherein the control switch comprises: an alternating current contactor;
the normally open contact of the alternating current contactor is arranged on the main loop of the electric heater; the electromagnetic coil of the alternating current contactor is arranged between an alternating current power supply of the main board (10) and a control signal output interface of the main board (10).
4. A device according to claim 3, wherein the control switch failure comprises: and normally open contacts of the alternating current contactor are adhered.
5. The device according to one of claims 1, 2, 4, characterized in that the optocoupler (20) is arranged on the motherboard (10).
6. A device according to claim 3, characterized in that the optocoupler (20) is arranged on the motherboard (10).
7. An air conditioning unit, comprising: an electric heater protection device as claimed in any one of claims 1 to 6.
8. A method of protecting an electric heater of an air conditioning unit as set forth in claim 7, comprising:
the main loop of the electric heater is controlled to be electrified or powered off according to a control signal output by the main board (10) through a control switch;
outputting the control signal to the control switch; or,
and under the condition that the electric heater does not work normally, if the main board (10) for outputting the control signal detects a low-level signal output by the optical coupler (20) connected to the main board (10) due to conduction, a first prompt message of the control switch fault is sent out.
9. The method as recited in claim 8, further comprising:
-connecting the optocoupler (20) also to both ends of the electric heater; the method comprises the steps of,
if the optical coupler (20) is detected to be conducted, determining that a main loop of the electric heater works normally; or,
if the optocoupler (20) is detected to be not conducted, the fuse and/or the temperature limiter are/is determined to be disconnected.
10. The method of claim 9, wherein determining that the fuse and/or the temperature limiter are open comprises:
if the duration time of the non-conduction of the optocoupler is longer than the set duration time, determining that the fuse is disconnected, and initiating a second prompting message of the disconnection of the fuse; or,
if the duration of non-conduction of the optocoupler is smaller than or equal to the set duration, the fact that the temperature limiter is disconnected and the fuse is not disconnected is determined.
11. The method according to one of claims 8-10, further comprising:
the main circuit of the electric heater is subjected to first over-temperature protection based on a first set temperature through a fuse; and/or the number of the groups of groups,
the temperature limiter is used for performing second over-temperature protection based on a second set temperature on the main circuit of the electric heater; the second set temperature is less than the first set temperature.
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CN108152723A (en) * 2017-11-15 2018-06-12 珠海格力电器股份有限公司 Direct current contactor adhesion detection device and method
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FR2625820A1 (en) * 1988-01-08 1989-07-13 Landis & Gyr Ag METHOD AND APPARATUS FOR TESTING A SAFETY TEMPERATURE LIMITER FOR A HEATING SYSTEM
JP2007155264A (en) * 2005-12-07 2007-06-21 Sharp Corp Air conditioner
CN103955246A (en) * 2014-05-12 2014-07-30 珠海格力电器股份有限公司 Electric heater control system and method
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