CN210222578U

CN210222578U - Control circuit of mute heat preservation kettle

Info

Publication number: CN210222578U
Application number: CN201921665393.2U
Authority: CN
Inventors: Xiaoping Chen; 陈小平; Lihua He; 何礼华
Original assignee: Foshan Viomi Electrical Technology Co Ltd
Current assignee: Foshan Viomi Electrical Technology Co Ltd
Priority date: 2019-09-29
Filing date: 2019-09-29
Publication date: 2020-03-31
Anticipated expiration: 2029-09-29

Abstract

The utility model discloses a control circuit of a mute heat preservation kettle, which comprises a live wire terminal ACL, a zero wire terminal ACN, an AC-DC circuit, a voltage stabilizing circuit, a heating tube RL, a relay circuit, a silicon controlled circuit and an optocoupler circuit; the live wire terminal ACL is electrically connected with one contact of the relay circuit, the other contact of the relay circuit is electrically connected with one end of the heating tube RL, and the other end of the heating tube RL is electrically connected with the zero wire terminal ACN; the input end of the relay circuit is electrically connected with an external control unit; the thyristor circuit is connected between two contacts of the relay circuit in parallel, and the optical coupling circuit is electrically connected with the thyristor circuit; the input end of the optical coupling circuit is electrically connected with an external control unit; the utility model aims at providing a control circuit of silence heat preservation kettle, when the rapid heating, the device heaies up for a short time, when keeping warm, can frequent break-make reaches accurate control temperature.

Description

Control circuit of mute heat preservation kettle

Technical Field

The utility model relates to a kettle equipment technical field especially relates to a control circuit of silence heat preservation kettle.

Background

The scheme that is applied to insulating of insulating pot now has three: the first is to use PTC automatic heating temperature control, and this kind of mode has used PTC self characteristic to realize heating limit temperature, but the heat preservation temperature is fixed (generally 50 ℃), and the user can not set up the adjustment, and the heat preservation precision is lower, generally uses on low-cost mechanical kettle.

The second is to use relay and temperature sensing device to realize heat preservation and temperature control, this kind of mode detects the switching of water temperature control relay through the temperature sensing device and realizes heating and temperature control, and the heat preservation temperature can be set up the adjustment by the user, but the temperature control precision can not be made too high, generally more than 5 ℃. The higher the temperature control precision is, the more the switching frequency of the relay of the kettle in the heat preservation stage is, the longer the contact is consumed by igniting when the relay is switched on and off, and the service life of the kettle is finally greatly shortened. When the temperature is kept, the relay is closed and is heated at full power, so that great noise can be caused, and the rest of a user is influenced.

The third is to use the silicon controlled rectifier and temperature sensing device to realize the heat preservation and temperature control, this way can realize the adjustable temperature of heat preservation, accurate temperature control and silent heat preservation, but when the kettle is boiled, the full power is heated, the silicon controlled rectifier heats seriously, need to install very big air-cooling fin to assist the heat dissipation, is not favorable to the structural design; moreover, the circuit board is generally placed near the lower part of the heating tube, so that the environmental temperature is higher, and the heat dissipation is not facilitated.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a control circuit of silence heat preservation kettle, when the rapid heating, the device heaies up for a short time, when keeping warm, can frequent break-make reach the accurate control temperature.

To achieve the purpose, the utility model adopts the following technical proposal: a control circuit of a mute heat preservation kettle comprises a live wire terminal ACL, a zero wire terminal ACN, an AC-DC circuit, a voltage stabilizing circuit, a heating tube RL, a relay circuit, a silicon controlled circuit and an optocoupler circuit; the live wire terminal ACL is electrically connected with one contact of the relay circuit, the other contact of the relay circuit is electrically connected with one end of the heating tube RL, and the other end of the heating tube RL is electrically connected with the zero wire terminal ACN; the input end of the relay circuit is electrically connected with an external control unit; the thyristor circuit is connected between two contacts of the relay circuit in parallel, and the optical coupling circuit is electrically connected with the thyristor circuit; the input end of the optical coupling circuit is electrically connected with an external control unit; the AC-DC circuit is connected in parallel between the live wire terminal ACL and the zero wire terminal ACN, and the voltage stabilizing circuit is electrically connected with the AC-DC circuit.

Preferably, the relay circuit comprises a diode D1, a relay REL1, a transistor Q2, a resistor R5 and a resistor R6, the diode D1 is connected in parallel with the relay REL1, a positive terminal of the diode D1 and one coil terminal of the relay REL1 are both electrically connected with the AC-DC circuit, and a negative terminal of the diode D1 and the other coil terminal of the relay REL1 are both electrically connected with a collector of the transistor Q2; the resistor R6 is connected in parallel between the base electrode and the emitter electrode of the triode Q2, one end of the resistor R5 is electrically connected with the base electrode of the triode Q2, and the other end of the resistor R5 is electrically connected with an external control unit; the emitter of the transistor Q2 is grounded.

Preferably, the thyristor circuit includes thyristor Q1, resistance R2 and resistance R4, the first electrode and the second electrode of thyristor Q1 respectively with two contacts of relay REL1 are parallelly connected, the control pole of thyristor Q1 with the opto-coupler circuit electricity is connected, resistance R4 is parallelly connected between the second electrode and the control pole of thyristor Q1, the first electrode of thyristor Q1 with the opto-coupler circuit electricity is connected.

Preferably, the optical coupling circuit comprises a MOC3063 chip and a resistor R3, a first output end of the MOC3063 chip is electrically connected with one end of the resistor R2, a second output end of the MOC3063 chip is electrically connected with one end of the resistor R4, and two ends of the resistor R3 are respectively connected with a positive electrode of the MOC3063 chip and an external control unit; and the cathode of the MOC3063 chip is grounded.

Preferably, a voltage dependent resistor MOV1 is connected in parallel between the live terminal ACL and the neutral terminal ACN; and the live wire terminal ACL is connected with a protective tube FU.

Preferably, the AC-DC circuit adopts LN8K05A chip.

Preferably, the voltage stabilizing circuit adopts an LM1117 chip.

The utility model discloses realize the parallelly connected silicon controlled rectifier of relay and temperature sensing device and boil and heat retaining mode, this kind of mode size is little, and temperature adjustable, temperature control precision is high and the heat preservation noise is little to can also protect the relay contact, thereby prolong the life of relay and prolong the life of insulating pot.

Drawings

The accompanying drawings are provided to further illustrate the present invention, but the content in the accompanying drawings does not constitute any limitation to the present invention.

Fig. 1 is a schematic diagram of the circuit principle of the present invention;

fig. 2 is a control timing diagram of the relay and the thyristor of the present invention.

Wherein: the circuit comprises an AC-DC circuit 1, a voltage stabilizing circuit 2, a relay circuit 3, a silicon controlled rectifier circuit 4 and an optical coupling circuit 5.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.

Referring to fig. 1 and 2, the control circuit of the mute thermal insulation kettle of the embodiment includes a live wire terminal ACL, a null wire terminal ACN, an AC-DC circuit 1, a voltage stabilizing circuit 2, a heating tube RL, a relay circuit 3, a silicon controlled circuit 4, and an opto-coupler circuit 5.

The live wire terminal ACL is electrically connected with one contact of the relay circuit 3, the other contact of the relay circuit 3 is electrically connected with one end of the heating tube RL, and the other end of the heating tube RL is electrically connected with the zero wire terminal ACN; the input end of the relay circuit 3 is electrically connected with an external control unit; the thyristor circuit 4 is connected between two contacts of the relay circuit 3 in parallel, and the optocoupler circuit 5 is electrically connected with the thyristor circuit 4; and the input end of the optical coupling circuit 5 is electrically connected with an external control unit.

The AC-DC circuit 1 is connected in parallel between the live wire terminal ACL and the zero wire terminal ACN, and the voltage stabilizing circuit 2 is electrically connected with the AC-DC circuit 1.

By adopting the structure, the working state of the heating tube RL is controlled by the cooperation of the relay circuit 3 and the silicon controlled circuit 4, when the water boiling state is normal or the temperature is lower than the heat preservation temperature for a large amount, the relay circuit 3 is closed, and the heating tube RL is heated at full power; when the circuit is in a heat preservation state, the relay circuit 3 is disconnected and does not work, the heating tube RL is controlled to be heated intermittently at low power generally less than 300W by closing or opening the silicon controlled rectifier circuit 4, and the heat preservation effect is achieved.

The on-off of the live wire is controlled through the relay circuit 3 and the silicon controlled circuit 4, and the effects of safety and reliability are achieved.

By adopting the circuit structure, the size of the circuit structure is small, the temperature rise of the device is small when the full attack rate is heated, the heat preservation temperature is adjustable, the precise temperature control and the mute temperature control are realized, meanwhile, the contact of the relay can be protected, and the service life of the kettle is prolonged. The circuit structure not only can be used as a heating control circuit of a kettle, but also can be applied to the heat preservation of other household appliances, such as a health preserving kettle, a wall breaking machine and the like.

The operating principle of the thyristor circuit 4 is that the output power of the heating tube RL is reduced by controlling the heating tube RL to be frequently switched on and off, because the thyristor circuit 4 belongs to an electronic switch, the service life times of controlling the on and off of a heating loop are theoretically unlimited, no mechanical action sound is generated in the on-off process, the service life of the relay circuit 3 is directly related to the on-off times of the load, the on-off process of the load can generate contact ignition, consume contacts and generate the on-off action sound of clicking. Because the relay is easy to consume contacts when the relay is switched on and off with a load, and the service life of the on-off of the silicon controlled rectifier is not limited, the on-off of the relay is assisted by the silicon controlled rectifier, the contact ignition consumption of the relay is reduced, and the service life of the relay is prolonged.

The specific working process is as follows, the relay circuit 3 is in an off state, if the relay circuit 3 is controlled to be closed at the Ton moment, the thyristor circuit 4 is closed at the Ton-t0 moment in advance by t0, the heating tube RL is pre-conducted through the thyristor circuit 4, the relay is closed at the Ton moment, the thyristor circuit 4 is opened at the Ton + t1 moment after t1 is delayed, the relay circuit 3 is still in the on state, and the heating tube RL is conducted.

The relay circuit 3 is in a closed state, if the relay circuit 3 is controlled to be opened at the time of Toff, the thyristor is closed at the time of Toff-t2 in advance of t2, the relay circuit 3 is opened at the time of Toff, the heating tube RL is still in a conducting state through the thyristor circuit 4, the thyristor circuit 4 is opened at the time of Ton + t3 after the delay of t3, and the heating tube RL is opened. The on-off of the relay circuit 3 is carried out with the help of the silicon controlled circuit 4, so that the ignition consumption of the relay contact can be greatly reduced, and the service life of the relay is prolonged.

Preferably, the relay circuit 3 includes a diode D1, a relay REL1, a transistor Q2, a resistor R5, and a resistor R6, the diode D1 is connected in parallel to the relay REL1, a positive terminal of the diode D1 and one coil terminal of the relay REL1 are both electrically connected to the AC-DC circuit 1, and a negative terminal of the diode D1 and the other coil terminal of the relay REL1 are both electrically connected to a collector of the transistor Q2.

The resistor R6 is connected in parallel between the base and the emitter of the triode Q2, one end of the resistor R5 is electrically connected with the base of the triode Q2, and the other end of the resistor R5 is electrically connected with an external control unit. The emitter of the transistor Q2 is grounded.

By adopting the structure, the relay REL1 controls the heating tube RL to heat, because the relay REL1 is not suitable for frequent on-off, and the frequent on-off can shorten the contact life of the relay REL1, the control process generally comprises that the water temperature is lower than the lower heat preservation threshold Tlow, the relay is closed to heat with full power, the water temperature is higher than the upper heat preservation threshold Thigh, the relay is disconnected to stop heating, the difference value between the Thigh and the Tlow is generally more than 10 ℃, and the kettle is convenient to select a control mode.

Preferably, the thyristor circuit 4 includes a thyristor Q1, a resistor R2 and a resistor R4, a first electrode and a second electrode of the thyristor Q1 are respectively connected in parallel with two contacts of the relay REL1, a control electrode of the thyristor Q1 is electrically connected with the optical coupling circuit 5, the resistor R4 is connected in parallel between the second electrode and the control electrode of the thyristor Q1, and the first electrode of the thyristor Q1 is electrically connected with the optical coupling circuit 5.

With this structure, the resistor R2 acts as a current limiting resistor, and the current at its output terminal does not exceed 1A. The thyristor Q1 has a current less than or equal to 0.5mA in the off state of the output end, and the resistor R4 can eliminate the influence of the current on the circuit. The silicon controlled rectifier circuit 4 uses a silicon controlled rectifier optocoupler with a zero-crossing on-off function, and a circuit structure does not need to be designed with a circuit for detecting a zero-crossing signal, so that the circuit structure is relatively simple and small in size.

In the heat preservation state, the heat dissipation capacity of the electric kettle is not large, the heat provided for the electric kettle by low-power heating is not large, and the output heating power of the heating tube RL is also not large, so the mute effect is good. The controllable silicon Q1 can be frequently switched on and off, so the temperature control precision of the kettle is higher, and simultaneously, the controllable silicon Q1 can support a user to set different heat preservation temperatures by matching with an external control unit. The controllable silicon Q1 controls the output heating power of the heating tube RL to be lower, the self heating value is smaller, the requirement can be met only by self heat dissipation, no extra large-size heat dissipation sheet is needed to assist heat dissipation, and the size of the circuit board is reduced.

Preferably, the optical coupling circuit 5 comprises a MOC3063 chip and a resistor R3, a first output end of the MOC3063 chip is electrically connected with one end of the resistor R2, a second output end of the MOC3063 chip is electrically connected with one end of the resistor R4, and two ends of the resistor R3 are respectively connected with a positive electrode of the MOC3063 chip and an external control unit; and the cathode of the MOC3063 chip is grounded.

By adopting the structure, the MOC3063 chip is adopted as the bidirectional thyristor output type optical coupler, the optical coupler has a zero-crossing detection and trigger circuit, the control current of the input end of the optical coupler is 5mA, the rated voltage of the output end of the optical coupler is 600V, and the separation voltage between the input end and the output end of the optical coupler is 7500V, so that the optical coupler has the advantage of high control precision.

With this structure, the voltage can be protected and clamped to a relatively fixed voltage value through the piezoresistor MOV1, and the protection effect on the subsequent circuit is achieved. The fuse tube FU is arranged to protect the circuit.

Preferably, the AC-DC circuit 1 uses an LN8K05A chip.

With the structure, the AC-DC circuit 1 which is formed by adopting the LN8K05A chip as a core can convert alternating current into a non-isolated low-voltage direct current power supply VCC to supply power for the relay circuit 3.

Preferably, the voltage stabilizing circuit 2 adopts an LM1117 chip.

With this structure, the voltage regulator circuit 2 formed by using the LM1117 chip as a core can keep the output voltage stable.

When the heating device works, the control unit sends a signal to switch on the relay circuit 3, two contacts of the relay REL1 are closed, and the heating tube RL carries out full-attack heating to achieve the purpose of rapid heating; when the temperature reaches the set stability, the control unit sends a signal to disconnect the relay circuit 3, two contacts of the relay REL1 are disconnected, and the heating tube RL stops heating. In the heat preservation state, the control unit sends a signal to switch on the thyristor circuit 4, the thyristor Q1 outputs low power, the heating tube RL is heated discontinuously, the heat preservation is carried out, the thyristor circuit 4 reduces the contact ignition consumption of the relay Q1, and the service life of the relay is prolonged.

The technical principle of the present invention is described above with reference to specific embodiments. The description is made for the purpose of illustrating the principles of the invention and should not be construed in any way as limiting the scope of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without any inventive effort, which would fall within the scope of the present invention.

Claims

1. A control circuit of a mute heat preservation kettle is characterized by comprising a live wire terminal ACL, a zero wire terminal ACN, an AC-DC circuit, a voltage stabilizing circuit, a heating tube RL, a relay circuit, a silicon controlled circuit and an optical coupler circuit;

the live wire terminal ACL is electrically connected with one contact of the relay circuit, the other contact of the relay circuit is electrically connected with one end of the heating tube RL, and the other end of the heating tube RL is electrically connected with the zero wire terminal ACN; the input end of the relay circuit is electrically connected with an external control unit; the thyristor circuit is connected between two contacts of the relay circuit in parallel, and the optical coupling circuit is electrically connected with the thyristor circuit; the input end of the optical coupling circuit is electrically connected with an external control unit;

the AC-DC circuit is connected in parallel between the live wire terminal ACL and the zero wire terminal ACN, and the voltage stabilizing circuit is electrically connected with the AC-DC circuit.

2. The control circuit of a mute thermal water bottle as claimed in claim 1, wherein the relay circuit comprises a diode D1, a relay REL1, a transistor Q2, a resistor R5 and a resistor R6, the diode D1 is connected in parallel with the relay REL1, the positive terminal of the diode D1 and one coil terminal of the relay REL1 are both electrically connected with the AC-DC circuit, and the negative terminal of the diode D1 and the other coil terminal of the relay REL1 are both electrically connected with the collector of the transistor Q2;

the resistor R6 is connected in parallel between the base electrode and the emitter electrode of the triode Q2, one end of the resistor R5 is electrically connected with the base electrode of the triode Q2, and the other end of the resistor R5 is electrically connected with an external control unit;

the emitter of the transistor Q2 is grounded.

3. The control circuit of the mute heat preservation kettle as claimed in claim 1, wherein the silicon controlled circuit comprises a silicon controlled rectifier Q1, a resistor R2 and a resistor R4, a first electrode and a second electrode of the silicon controlled rectifier Q1 are respectively connected with two contacts of the relay REL1 in parallel, a control electrode of the silicon controlled rectifier Q1 is electrically connected with the optical coupling circuit, the resistor R4 is connected between the second electrode and the control electrode of the silicon controlled rectifier Q1 in parallel, and the first electrode of the silicon controlled rectifier Q1 is electrically connected with the optical coupling circuit.

4. The control circuit of a mute thermos according to claim 3, wherein the optical coupling circuit comprises a MOC3063 chip and a resistor R3, a first output end of the MOC3063 chip is electrically connected with one end of the resistor R2, a second output end of the MOC3063 chip is electrically connected with one end of the resistor R4, and two ends of the resistor R3 are respectively connected with an anode of the MOC3063 chip and an external control unit; and the cathode of the MOC3063 chip is grounded.

5. The control circuit of a silent thermal bottle according to claim 1, wherein a voltage dependent resistor MOV1 is connected in parallel between said live terminal ACL and said neutral terminal ACN; and the live wire terminal ACL is connected with a protective tube FU.

6. The control circuit of the mute thermal insulation kettle according to claim 1, wherein the AC-DC circuit adopts LN8K05A chip.

7. The control circuit of the mute thermal insulation kettle according to claim 1, wherein the voltage regulator circuit adopts an LM1117 chip.