CN113249930B

CN113249930B - Heating control circuit, heating control method, washing machine and dryer

Info

Publication number: CN113249930B
Application number: CN202110440170.1A
Authority: CN
Inventors: 崔增良
Original assignee: Hisense Refrigerator Co Ltd
Current assignee: Hisense Refrigerator Co Ltd
Priority date: 2021-04-21
Filing date: 2021-04-21
Publication date: 2023-04-11
Anticipated expiration: 2041-04-21
Also published as: CN113249930A

Abstract

The application discloses heating control circuit, heating control method, washing machine, drying-machine, heating control circuit includes: a heating unit for heating an environment; the temperature measuring unit is used for measuring the temperature of the environment to obtain the current temperature of the environment; the first end of the PWM control unit is connected with the temperature measuring unit and used for adjusting the duty ratio of the PWM control signal according to the difference value between the preset temperature and the current temperature and generating a target PWM control signal, wherein the duty ratio of the target PWM control signal is positively correlated with the difference value; and the control end of the switch unit is connected with the second end of the PWM control unit, and the output end of the switch unit is connected with the heating unit and is used for switching on or switching off according to the target PWM control signal so as to control the heating unit to be started or switched off. This application improves temperature control precision, shortens and adds duration, promotes user experience.

Description

Heating control circuit, heating control method, washing machine and dryer

Technical Field

The application relates to the technical field of electromechanical control, in particular to a heating control circuit, a heating control method, a washing machine and a dryer.

Background

Along with the improvement of the requirement of people on clothes cleaning, a plurality of washing machines are additionally provided with an electric heating function, and the clothes are washed by utilizing warm water, so that the cleaning degree of the clothes is improved. The clothes dryer utilizes electric heating to evaporate and dry moisture in washed clothes instantly, and is particularly needed for the conditions that the clothes are difficult to dry in winter in the north and in 'backsouth' in the south.

The heating control precision of the heating control circuit of the existing washing machine or clothes dryer is not high, so that the clothes are damaged due to overhigh water temperature of the washing machine, and the washing effect of the clothes is poor due to overlow water temperature; the clothes are damaged due to overhigh drying temperature of the clothes dryer, and the drying effect is poor due to overhigh drying temperature. Meanwhile, in order to maintain the constant temperature, in a heating control circuit of the existing washing machine or clothes dryer, when the water temperature or the drying temperature reaches a set temperature, the alternating current contactor is disconnected, the electric heating is stopped, when the water temperature or the drying temperature is lower than the preset temperature, the alternating current contactor is closed again, the electric heating is carried out, the heating is frequently carried out until the washing is finished or the drying is finished, the heating time or the drying time is prolonged, and the user experience is poor.

Therefore, a high-precision heating control circuit is needed to improve the user experience.

Disclosure of Invention

The embodiment of the application provides a heating control circuit, a heating control method, a washing machine and a dryer, and then can solve the problems of low heating control precision and long heating time at least to a certain extent, improve the temperature control precision, shorten the heating or drying time, and improve the user experience.

Other features and advantages of the present application will be apparent from the following detailed description, or may be learned by practice of the application.

According to a first aspect of embodiments of the present application, there is provided a heating control circuit, including:

a heating unit for heating an environment;

the temperature measuring unit is used for measuring the temperature of the environment to obtain the current temperature of the environment;

a Pulse Width Modulation (PWM) control unit, a first end of which is connected to the temperature measurement unit, and is configured to adjust a duty ratio of a PWM control signal according to a difference between a preset temperature and the current temperature, and generate a target PWM control signal, where the duty ratio of the target PWM control signal is positively correlated with the difference;

and the control end of the switch unit is connected with the second end of the PWM control unit, and the output end of the switch unit is connected with the heating unit and is used for being switched on or switched off according to the target PWM control signal so as to control the heating unit to be switched on or switched off.

Optionally, the heating control circuit further includes:

the power supply unit, the heating unit and the switch unit form a first loop and are used for supplying power to the heating unit;

the current sampling unit is connected in series between the switch unit and the power supply unit and is used for sampling the current of the first loop to obtain the current of the first loop;

and the third end of the PWM control unit is connected with the current sampling unit, and the PWM control unit is also used for generating the target PWM control signal according to the current temperature and the current so as to drive the switching unit to be switched on or switched off.

Optionally, the heating control circuit further includes:

the voltage sampling unit is connected with the power supply unit in parallel and is used for sampling the voltage of the power supply unit to obtain the current voltage of the power supply unit;

the fourth end of the PWM control unit is connected with the voltage sampling unit, and the PWM control unit is further configured to generate the target PWM control signal according to the current temperature, the current, and the current voltage, so as to drive the switching unit to be turned on or turned off.

Optionally, the PWM control unit includes:

the microprocessor unit is connected with the temperature measuring unit and used for adjusting the duty ratio of a PWM control signal according to the difference value between the preset temperature and the current temperature and generating an original PWM control signal, wherein the duty ratio of the original PWM control signal is positively correlated with the difference value;

and the optical coupling isolation unit is connected with the microprocessor unit at one end and connected with the switch unit at the other end, is used for carrying out level conversion on the original PWM control signal to generate the target PWM control signal, and is used for electrically isolating the microprocessor unit from the switch unit.

Optionally, the PWM control unit further includes:

the level overturning unit is connected between the microprocessor unit and the optical coupling isolation unit in series and is used for carrying out level overturning on the original PWM control signal;

and the optical coupling isolation unit is also used for carrying out level conversion on the overturned original PWM control signal to generate the target PWM control signal.

Optionally, the heating unit includes N heating subunits, where N is greater than or equal to 1;

the switch unit comprises N paths of switch subunits, and the switch subunits correspond to the heating subunits one by one;

the PWM control unit comprises N paths of PWM control subunits, and the PWM control subunits correspond to the switch subunits one to one.

Optionally, the switching unit is an MOS transistor or an IGBT.

According to a second aspect of embodiments of the present application, there is provided a heating control method applied to the heating control circuit of the first aspect, the heating control method including:

acquiring a preset temperature;

acquiring the current temperature of the environment;

and adjusting the duty ratio of a PWM control signal according to a preset temperature and the difference value of the current temperature to generate a target PWM control signal so as to control the on-time and off-time of the switch unit, wherein the duty ratio of the target PWM control signal is positively correlated with the difference value.

According to a third aspect of embodiments of the present application, there is provided a washing machine including the heating control circuit of the first aspect described above.

According to a fourth aspect of embodiments of the present application, there is provided a dryer including the heating control circuit of the first aspect described above.

According to the embodiment of the application, the on-off time of the duty ratio control switch unit of the PWM control signal is adjusted through the difference value of the preset temperature and the current temperature of the environment, so that the input control of the heating unit is controlled, the smooth rising and the stable heat preservation of the temperature are realized, the temperature control precision is improved, the heating time is shortened, and the user experience is improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the principles of the application. It is obvious that the drawings in the following description are only some embodiments of the application, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

fig. 1 is a schematic structural diagram of a heating control circuit according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of another heating control circuit provided in the embodiment of the present application;

fig. 3 is a schematic structural diagram of another heating control circuit provided in the embodiment of the present application;

fig. 4 is a schematic structural diagram of a PWM control unit according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of another PWM control unit according to an embodiment of the present application;

FIG. 6 is a schematic structural diagram of another heating control circuit provided in the embodiment of the present application;

FIG. 7 is a circuit diagram of a heating control circuit according to an embodiment of the present application;

FIG. 8 is a block diagram illustrating a microprocessor unit according to an embodiment of the present disclosure;

FIG. 9 is a flow chart of a heating control method according to an embodiment of the present disclosure;

FIG. 10 is a flow chart of another heating control method provided by an embodiment of the present application;

FIG. 11 is a flow chart of another heating control method provided in an embodiment of the present application;

fig. 12 is a flowchart of another heating control method according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the subject matter of the present application can be practiced without one or more of the specific details, or with other methods, components, devices, steps, and so forth. In other instances, well-known methods, devices, implementations, or operations have not been shown or described in detail to avoid obscuring aspects of the application.

The block diagrams shown in the figures are functional entities only and do not necessarily correspond to physically separate entities. I.e. these functional entities may be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different networks and/or processor means and/or microcontroller means.

The flow charts shown in the drawings are merely illustrative and do not necessarily include all of the contents and operations/steps, nor do they necessarily have to be performed in the order described. For example, some operations/steps may be decomposed, and some operations/steps may be combined or partially combined, so that the actual execution sequence may be changed according to the actual situation.

In the description of the present application, it is to be understood that the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, the meaning of "a plurality" is two or more unless otherwise specified.

The heating control circuit provided by the embodiment of the application can be applied to a washing machine, a dryer or other electrical equipment related to a heating function, a high-precision heating function is provided for the washing machine, the dryer or other electrical equipment related to the heating function, the heating time is shortened, and the user experience is improved.

Fig. 1 is a schematic structural diagram of a heating control circuit according to an embodiment of the present disclosure, and as shown in fig. 1, the heating control circuit includes a heating unit 110, a temperature measuring unit 120, a PWM control unit 130, and a switch unit 140, which are described below.

The heating unit 110 is used to heat the environment.

In the embodiment of the application, the heating unit 110 can adopt ceramic heating equipment, the shell of the ceramic heating equipment is made of stainless steel sheets, the resistance wire is worn inside the ceramic with higher insulating fire resistance degree, the equipment can work by switching on the power supply, and the equipment is flexible and convenient to mount, high-temperature resistant, fast in heat transfer and good in insulation.

In this application embodiment, heating element 110 also can adopt stainless steel firing equipment, stainless steel firing equipment distributes the high temperature resistance wire uniformly in high temperature resistant stainless steel seamless pipe, pack the equal good crystallization magnesium oxide powder of thermal conductivity and insulating properties densely at the space part, when having the electric current to pass through in the high temperature resistance wire, the heat of production passes through crystallization magnesium oxide powder to tubular metal resonator surface diffusion, retransfer to by in heating member or the air go, reach the purpose of heating, high thermal efficiency, and it is even to generate heat.

The temperature measuring unit 120 is used for measuring the temperature of the environment to obtain the current temperature of the environment.

In this embodiment, the temperature measuring unit 120 may adopt a high-precision temperature sensor with a measurement precision of 0.1 ℃, and includes: temperature sensors such as thermocouples, thermistors, platinum Resistors (RTDs), and temperature ICs. Such as: the thermistor is made of semiconductor materials, mostly has a negative temperature coefficient, namely, the resistance value decreases along with the increase of temperature, and the change of temperature can cause large resistance value change, so that the thermistor temperature sensor is a very sensitive temperature sensor.

A first end of the PWM control unit 130 is connected to the temperature measurement unit 120, and is configured to adjust a duty ratio of the PWM control signal according to a difference between a preset temperature and a current temperature, and generate a target PWM control signal, where the duty ratio of the target PWM control signal is positively correlated to the difference between the preset temperature and the current temperature.

In the embodiment of the present application, a washing machine, a dryer or other heating devices may set a plurality of temperature ranges, such as: the temperature is 30 ℃, 50 ℃, 70 ℃ and 90 ℃, and a user can set the preset temperature by selecting a gear according to actual requirements, for example, the preset temperature for washing the clothes in the washing machine is set to be 30 ℃ or the preset temperature for drying the clothes in the dryer is set to be 70 ℃.

In the embodiment of the present application, the target PWM control signal generated by the PWM control unit 130 is a digital signal which is mainly defined by two components, i.e. a duty ratio and a frequency, wherein the duty ratio means a percentage of a period of time of the signal in a high level state to a total period of time, and the frequency represents a speed of the PWM signal completing one period, i.e. a switching speed of the signal between the high level state and the low level state is determined.

In the embodiment of the present application, the PWM control unit 130 may output a PWM signal with an adjustable duty ratio to generate a target PWM control signal through an operation or logic determination module inside the MCU or the CPU by using internal hardware PWM modules such as the MCU and the CPU with high precision;

the MCU or the operation or logic judgment module in the CPU adjusts the duty ratio of the PWM control signal according to the difference value between the preset temperature and the current temperature of the environment, namely, the level of the output signal is adjusted through the duty ratio, and then the working time of the heating unit in the target PWM control signal period is controlled subsequently. For example, a user of the washing machine or the dryer sets a preset temperature to 50 ℃, the PWM module adopts a switching frequency of 400HZ, initially sets a duty ratio of the PWM control signal to 95% of a maximum value, and prompts the heating unit 110 to rapidly heat up, adjusts the duty ratio of the PWM control signal to decrease when the current temperature reaches 45 ℃, and prompts a heating speed of the heating unit 110 to slow down, and sets the duty ratio of the PWM control signal to 5% of a minimum value when the current temperature approaches 50 ℃, and prompts the heating speed of the heating unit 110 to decrease to a minimum value, so that the current temperature can be smoothly raised to 50 ℃ and stably maintained at 50 ℃ until the laundry is washed or dried.

The control terminal of the switching unit 140 is connected to the second terminal of the PWM control unit 130, the output terminal is connected to the heating unit 110, and the switching unit 140 is configured to be turned on or off according to a target PWM control signal to control the heating unit 110 to be turned on or off.

In the embodiment of the present application, the switch unit 140 may be a MOS switch Transistor (MOSFET) or an IGBT (Insulated Gate Bipolar Transistor).

For example, in the embodiment of the present application, an N-type MOS switch tube is adopted, a G pole of a control end of the MOS tube is connected to the second end of the PWM control unit 130, an S pole of an input end of the MOS tube is grounded, an N pole of an output end of the MOS tube is connected to the heating unit 110, when a target PWM control signal is at a high level, a voltage between the G pole and the S pole of the MOS tube is greater than a turn-on voltage of the MOS tube, the MOS tube is turned on, the heating unit 110 operates, when the target PWM control signal is at a low level, the voltage between the G pole and the S pole of the MOS tube is less than the turn-on voltage of the MOS tube, the MOS tube is turned off, and the heating unit 110 stops operating.

For example, in the embodiment of the present application, an N-type IGBT is adopted, a G pole of a control end of the IGBT is connected to the second end of the PWM control unit 130, an E pole of an input end of the IGBT is grounded, and a C pole of an output end of the IGBT is connected to the heating unit 110, when a target PWM control signal is at a high level, a voltage between the G pole and the E pole of the IGBT is greater than a turn-on voltage of the IGBT, the IGBT is turned on, the heating unit 110 operates, and when the target PWM control signal is at a low level, a voltage between the G pole and the E pole of the IGBT is less than the turn-on voltage of the IGBT, the IGBT is turned off, and the heating unit 110 stops operating.

In the embodiment of the present application, the PWM control unit 130 is not used as a power supply of the heating unit, but input control of the heating unit 110 is implemented through a MOS switch tube or an IGBT switch tube, a duty ratio of a target PWM control signal is adjusted through a difference between a current temperature and a preset temperature, and a working time of the heating unit 110 in a target PWM control signal period is finely managed, so that the heating unit 110 has different heating speeds at different temperature difference stages, thereby achieving smooth heating and stable heat preservation of the washing machine or the dryer, and avoiding that, in the existing electric heating control circuit, near the preset temperature, the current water temperature or the drying temperature is liable to change steeply, which causes too high water temperature to damage clothes or too low water temperature to affect a washing effect, and at the same time, the heating unit is caused to stop and start repeatedly, so as to prolong a heating time.

Fig. 2 is a schematic structural diagram of another heating control circuit provided in an embodiment of the present application, and as shown in fig. 2, the heating control circuit further includes a power supply unit 250 and a current sampling unit 260.

The power supply unit 250, the heating unit 210 and the switch unit 240 form a first loop for supplying power to the heating unit 210.

In this embodiment, the power supply unit 250 includes a rectifying and filtering module, and the rectifying and filtering module can convert the commercial power 220V into direct current to supply power to the heating unit 210.

The current sampling unit 260 is connected in series between the switching unit 240 and the power supply unit 250, and is configured to sample a current of the first loop to obtain a current of the first loop.

In the embodiment of the present application, the current sampling unit 260 may adopt a current transformer, when the current transformer operates, its secondary circuit is always closed, the operating state of the current transformer is close to a short circuit, the current in the first circuit can be accurately measured, and meanwhile, the current sampling unit can also play a role in overcurrent protection.

The third terminal of the PWM control unit 230 is connected to the current sampling unit 260, and the PWM control unit 230 is further configured to generate the target PWM control signal according to the current temperature and the current, so as to drive the switching unit 240 to be turned on or turned off.

In this embodiment, PWM control unit 230 still gathers the current of the first loop that heating unit 210 is located, synthesize preset temperature, the duty cycle of PWM control signal is adjusted to factors such as current temperature and current, in practical application, can combine preset temperature, current and heating unit's power to test, fit out best PWM control signal duty cycle adjustment function, the input of this function is preset temperature, current voltage and heating unit's power, the output is PWM control signal duty cycle, in order to realize that the temperature rises smoothly and steady heat preservation, promote user experience.

Fig. 3 is a schematic structural diagram of another heating control circuit provided in an embodiment of the present application, and as shown in fig. 3, the heating control circuit further includes a voltage sampling unit 370.

The voltage sampling unit 370 is connected in parallel with the power supply unit 350, and the voltage sampling unit 370 is configured to sample a voltage of the power supply unit 350 to obtain a current voltage of the power supply unit 350.

The fourth end of the PWM control unit 330 is connected to the voltage sampling unit 370, and the PWM control unit 330 is further configured to generate a target PWM control signal according to the current temperature, the current, and the current voltage, so as to drive the switch unit 340 to be turned on or turned off.

In this embodiment, the PWM control unit 230 further collects the current of the first loop in which the heating unit 310 is located, synthesize the preset temperature, the duty ratio of the PWM control signal adjusted by factors such as the current temperature and the current, in practical application, the preset temperature, the current, the current voltage and the power of the heating unit can be combined for testing, a best PWM control signal duty ratio adjustment function is fitted, the input of the function is the preset temperature, the current, the current voltage and the power of the heating unit, the output is the duty ratio of the PWM control signal, so as to realize smooth temperature rise and stable heat preservation, and improve user experience.

Fig. 4 is a schematic structural diagram of a PWM control unit provided in an embodiment of the present application, where the PWM control unit includes a microprocessor unit 431 and an optical coupler isolation unit 432.

The microprocessor unit 431 is connected to the temperature measuring unit, and is configured to adjust a duty ratio of the PWM control signal according to a difference between a preset temperature and a current temperature, and generate an original PWM control signal, where the duty ratio of the original PWM control signal is positively correlated to the difference.

In the embodiment of the present application, the PWM control unit 431 uses a hardware PWM module built in an MCU (micro controller unit), and outputs a PWM signal with an adjustable duty ratio through an operation or logic judgment module inside the MCU to generate an original PWM control signal.

One end of the optical coupling isolation unit 432 is connected with the microprocessor unit 431, the other end of the optical coupling isolation unit 432 is connected with the switch unit, and the optical coupling isolation unit 432 is used for performing level conversion on an original PWM control signal to generate a target PWM control signal and electrically isolating the microprocessor unit from the switch unit.

In this application embodiment, optical coupler 432 can adopt optical coupler, and optical coupler is equivalent to be in the same place emitting diode and phototriode encapsulation, and microprocessor unit 431 is connected to the emitting diode side, and the switch unit is connected to the phototriode side for there is not electric lug connection between the first return circuit at microprocessor unit 431 and switch unit place, prevent because of the interference that has electric connection and arouse, realize electrical isolation. Meanwhile, the high level voltage of the original PWM control signal generated by the MCU is also small and is not enough to drive the switch unit to be closed, so that the optical coupling isolation unit 432 is adopted to carry out level conversion on the original PWM control signal to drive the switch unit to be closed or closed in the embodiment of the application.

Fig. 5 is a schematic structural diagram of a PWM control unit according to an embodiment of the present disclosure, where the PWM control unit further includes a level flipping unit 533.

The level flipping unit 533 is connected in series between the microprocessor unit 531 and the optical coupling isolation unit 532, and is configured to perform level flipping on the original PWM control signal.

The optical coupling isolation unit 532 is further configured to perform level conversion on the inverted original PWM control signal to generate the target PWM control signal.

In the embodiment of the present application, level turning unit 533 has been set up between microprocessor unit 531 and opto-isolator unit 532, i.e. the low level in the original PWM control signal that microprocessor unit 531 produced is the high level after level turning unit 533 handles, the high level is the low level after level turning unit 533 handles, level turning unit 533 can adopt the transistor to realize, this kind of mode of level upset is realized through hardware in microprocessor unit 531's outside, remove the inside operation that realizes the level upset through software of microprocessor unit 531 from, level turning unit 533 can also play the amplification effect simultaneously.

Fig. 6 is a schematic structural diagram of a heating control circuit provided in an embodiment of the present application, and as shown in fig. 6, an example in which a heating unit includes 2 heating sub-units is described below.

The switch unit comprises 2-way switch subunits, and the switch subunits correspond to the heating subunits one by one;

the PWM control unit comprises 2 paths of PWM control subunits, and the PWM control subunits correspond to the switch subunits one to one.

In the embodiment of the application, multiple paths of heating subunits can be set according to the power of the heating unit, each path of heating subunit corresponds to one path of switch subunit and the PWM control subunit respectively, and the PWM control unit can select the number of paths opened by the PWM control subunit according to the preset temperature and the current temperature and further control the number of paths of the heating subunits.

For example, the washing machine or the dryer includes four preset temperature steps of 30 ℃, 50 ℃, 70 ℃ and 90 ℃, the whole heating control circuit includes 2 heating subunits, the PWM control unit selects to turn on one heating subunit or two heating subunits according to the steps of the preset temperature, when the user of the washing machine or the dryer sets the preset temperature to 70 ℃, the PWM control unit adopts a switching frequency of 400HZ, the 2 PWM control subunits are turned on to control the 2 heating subunits to work at the beginning, and the PWM control signal duty ratio is set to be 95% at the maximum value, so as to cause the 2 heating subunits to rapidly heat up, if the current temperature reaches 65 ℃, the 1 PWM control subunit is further turned on to control the 1 heating subunit to work, and the duty ratio of the PWM control signal is adjusted to be reduced, so as to cause the 1 heating subunit to slow down, if the current temperature approaches 70 ℃, the PWM control signal duty ratio is further set to be 5% at the minimum value, so as to cause the 1 heating subunit to slow down to the PWM control subunit to heat up to the minimum value, so as to ensure that the current temperature smoothly rises to 70 ℃ and smoothly keep the clothes at 70 ℃ until the clothes are washed or dried.

Fig. 7 is a circuit diagram of a heating control circuit according to an embodiment of the present application, and as shown in fig. 7, the heating control unit includes 2 paths of heating sub-units, 2 paths of switch sub-units, 2 paths of PWM control units, and the connection relationships of the 2 paths of sub-units are the same, and only one path of connection relationship is described here. In the embodiment of the present application, the heating control circuit includes a heating subunit 710, a temperature measuring unit 720, a PWM control subunit 730, and a switch subunit 740. Each of which is described below.

The heating subunit 710 includes a heating device CN104, and the heating device CN104 is used for heating the environment.

The temperature measuring unit 720 is used for measuring the temperature of the environment to obtain the current temperature of the environment. The temperature measuring unit 720 includes: temperature sensor chip CN7, first resistance R1, first electric capacity C1, first resistance R2, first polarity electric capacity E1.

And a grounding pin of the temperature sensor chip CN7 is grounded.

A first end of the first resistor R1 is connected to the digital signal output pin of the temperature SENSOR chip CN7, and a second end of the first resistor R is connected to the first end of the PWM control unit 730, and is configured to output an IPM _ SENSOR signal to the first end of the PWM control unit, where the IPM _ SENSOR signal is a current temperature.

One end of the first capacitor C1 is connected to the second end of the first resistor R1, and the other end is grounded.

First resistance R2, first end is connected with power VCC, and the second end is connected with first end of first resistance R1.

And the anode of the first polarity capacitor E1 is connected with the second end of the first resistor R2, and the cathode of the first polarity capacitor E1 is grounded and used for filtering.

The PWM control subunit 730 is configured to adjust a duty ratio of the PWM control signal according to a difference between the preset temperature and the current temperature, and generate a target PWM control signal, where the duty ratio of the target PWM control signal is positively correlated to the difference between the preset temperature and the current temperature. The PWM control subunit 730 includes a microprocessor unit, a level flip subunit, and an optical coupler isolation unit.

As shown in fig. 8, the microprocessor unit is an MCU chip. The Analog input/P2.2 pin of the MCU chip is connected to the second end of the first resistor R1, and is used to obtain the IPM _ SENSOR signal, i.e. the current temperature, from the second end of the first resistor R1.

An Analog input/P2.3 pin of the MCU chip is connected to an output terminal of the current sampling unit 760 for obtaining an I _ C signal, i.e. a current, from the output terminal of the current sampling unit 760.

The Analog input/P2.4 pin of the MCU chip is connected to the output terminal of the voltage sampling unit 770, and is used to obtain the V _ C signal, i.e. the current voltage, from the output terminal of the voltage sampling unit 770.

And a P0.0 pin and a P0.2 pin of the MCU chip respectively output a PWM control signal.

After the MCU chip acquires the current temperature, the current and the current voltage through the pins, the output path number of the PWM control signals can be controlled according to the difference value of the preset temperature and the current temperature, the current and the current voltage, the duty ratio of the PWM control signals is adjusted, and the original PWM control signals are generated, wherein the duty ratio of the original PWM control signals is positively correlated with the difference value of the preset temperature and the current temperature.

And the level inversion rotor unit is used for performing level inversion on the original PWM control signal. The level flip subunit includes: a third resistor R3, an N-type transistor Q0 and a fourth resistor R4.

And a first end of the third resistor R3 is connected with a P0.0 pin of the MCU chip.

The N-type transistor Q0, the B pole is connected with the second end of the third resistor R3, and the E pole is grounded.

And a first end of the fourth resistor R4 is connected with the B pole of the N-type transistor Q0, and a second end of the fourth resistor R is grounded.

In the embodiment of the application, level upset unit has been set up between microprocessor unit and opto-coupler isolation unit, the low level is the high level after level upset unit handles in original PWM control signal promptly, the high level is the low level after level upset unit handles, level upset unit can adopt the transistor to realize, this kind of mode that realizes the level upset through hardware in microprocessor unit's outside, remove microprocessor unit inside from and realize the level upset through software, level upset unit can also play the amplification simultaneously.

The optical coupling isolation unit is used for carrying out level conversion on the original PWM control signal to generate a target PWM control signal and is used for electrically isolating the microprocessor unit from the switch unit. The optical coupling isolation unit includes: a fifth resistor R5, a sixth resistor R6, a second capacitor C2, an optocoupler PQ0, a ninth resistor R9, and a rectifier diode ZD210.

And a first end of the fifth resistor R5 is connected with the C pole of the N-type transistor Q0.

And a first end of the sixth resistor R6 is connected with the power supply VCC, and a second end of the sixth resistor R6 is connected with a second end of the fifth resistor R5.

And a first end of the second capacitor C2 is connected with a 15V power supply.

In the optocoupler PQ0, the Anode pin is connected to the second end of the sixth resistor R6, the Cathode pin is connected to the first end of the fifth resistor R5, the Vcc pin is connected to the 15V power supply, the 2 Vo pins are connected to the first ends of the seventh resistor R7, the eighth resistor R8, and the Vee pin is connected to the second end of the second capacitor C2.

A first end of the ninth resistor R9 is connected to the second end of the seventh resistor R7 and the second end of the eighth resistor R8, respectively, and a second end of the ninth resistor R9 is connected to the second end of the second capacitor C2.

The anode of the rectifier diode ZD210 is connected to the second end of the ninth resistor R9, and the cathode thereof is connected to the first end of the ninth resistor R9.

The embodiment of the application adopts the optical coupler to be equivalent to the encapsulation of emitting diode and phototriode together, and the microprocessor unit is connected to the emitting diode side, and the phototriode side link switch unit for there is not electric lug connection between the first loop at microprocessor unit and switch unit place, prevents because of the interference that has electric connection to cause, realizes electrical isolation. Meanwhile, the high level voltage of the original PWM control signal generated by the microprocessor unit is also small and is not enough to drive the switch unit to be closed, so that the optical coupling isolation unit is adopted to carry out level conversion on the original PWM control signal to drive the switch unit to be closed or closed in the embodiment of the application;

the switch subunit 740 is used to close or open according to the target PWM control signal to control the heating unit to start or close. The switch subunit 740 includes: an IGBT1.

The G pole of the IGBT1 is connected to the first end of the ninth resistor R9, the E pole is connected to the second end of the second capacitor C2, and the C pole is connected to the heating unit CN 104.

The current sampling unit 760 is configured to perform current sampling on a first loop formed by the power supply unit CN103 and the heating unit to obtain a current, and the current sampling unit 760 includes: a tenth resistor R10, a third capacitor C3, a fourth capacitor C4 and a current transformer CT201.

And a first end of the tenth resistor R10 is connected with an Analog input/P2.3 pin of the MCU chip and used for sending an I _ C signal, namely the current, to the MCU chip.

And a first end of the third capacitor C3 is connected with a first end of the tenth resistor R10, and a second end thereof is grounded.

And a first end of the fourth capacitor C4 is connected with the power supply VCC, and a second end of the fourth capacitor C4 is grounded.

The current transformer CT201, the in-phase input end IP + of the current transformer CT201 is connected with the E pole of the IGBT 1; the reverse input end IP-is connected with the negative electrode of the power supply unit CN 103; the power supply pin VCC is respectively connected with a power supply VCC and a first end of a fourth capacitor C4; the VIOUT pin is connected with a second end of the tenth resistor R10; the ground pin GND is grounded.

The voltage sampling unit 770 is configured to perform voltage sampling on the voltage of the power supply unit CN103 to obtain a current voltage. The voltage sampling unit 770 includes: an eleventh resistor R11, a twelfth resistor R12, a rectifier diode ZD201, a thirteenth resistor R13, a fourteenth resistor R14, a fifth capacitor C5 and a sixth capacitor C6.

A first end of the eleventh resistor R11 is connected to the positive electrode of the power supply unit CN 103.

A first end of the twelfth resistor R12 is connected to the second end of the eleventh resistor R11, and a second end thereof is connected to the second end of the fifth resistor R5.

The anode of the rectifier diode ZD201 is connected to the cathode of the power supply unit CN103, and the cathode thereof is connected to the second end of the twelfth resistor R12.

A first end of the thirteenth resistor R13 is connected to the second end of the twelfth resistor R12, and a second end thereof is connected to the negative electrode of the power supply unit CN 103.

And a first end of the fourteenth resistor R14 is connected with an Analog input/P2.4 pin of the MCU chip and is used for sending a V _ C signal, namely the current voltage, to the MCU chip.

A first end of the fifth capacitor C5 is connected to the first end of the fourteenth resistor R14, and a second end thereof is grounded.

And a first end of the sixth capacitor C6 is connected with the power supply VCC, and a second end of the sixth capacitor C6 is grounded.

The anode of the rectifier diode ZD202 is grounded, and the cathode is connected to the second end of the fourteenth resistor R14.

In the voltage sampling chip IC1, a channel voltage in-phase input pin Sin + is connected with a first end of a thirteenth resistor R13, a channel voltage reverse-phase input pin Sin-is connected with a second end of the thirteenth resistor R13, a channel voltage in-phase output pin Sout + is connected with a second end of a fourteenth resistor R14, and a channel voltage reverse-phase output pin Sout-is grounded; the two-channel voltage non-inverting input Pin Pin + is connected to the power supply VCC, the two-channel voltage inverting input Pin Pin-is grounded, and the two-channel voltage inverting output Pin Pout-is connected to the Vee Pin of the optocoupler PQ 0.

The embodiment of the application provides a heating control circuit, measure current ambient temperature through the temperature measuring unit, measure current through the current sampling unit, measure current voltage through the voltage sampling unit, microprocessor unit is according to current temperature, current and current voltage adjustment PWM control signal's output way number and the duty ratio control heating unit of adjustment PWM control signal during the operating time of unit interval, improve the temperature control precision, realize smooth intensification and stable heat preservation in washing machine or the drying-machine, reduce the clothing damage or the clothing washing is unclean that the steep decline of temperature brought, reduce washing machine or drying-machine frequent heating time, promote user experience.

Fig. 9 is a flowchart of a heating control method according to an embodiment of the present application, which is applied to the heating control circuit shown in fig. 1, and the heating control method includes the following steps.

Step 910: and acquiring a preset temperature.

In the embodiment of the present application, for example, the washing machine or the dryer sets four preset temperature stages of 30 ℃, 50 ℃, 70 ℃ and 90 ℃, and the user can set the preset temperature by selecting the temperature stage.

Step 920: the current temperature of the environment is obtained.

In the embodiment of the application, the current temperature of the environment is obtained through the temperature measuring unit.

Step 930: and adjusting the duty ratio of the PWM control signal according to the difference value of the preset temperature and the current temperature to generate a target PWM control signal so as to control the on-time and the off-time of the switch unit, wherein the duty ratio of the target PWM control signal is positively correlated with the difference value of the preset temperature and the current temperature.

In the embodiment of the application, the PWM control unit may output the PWM signal with adjustable duty ratio to generate the target PWM control signal by using internal hardware PWM modules such as the MCU and the CPU and by using an operation or logic determination module inside the MCU or the CPU.

And an operation or logic judgment module in the MCU or the CPU adjusts the duty ratio of the PWM control signal according to the difference value between the preset temperature and the current temperature of the environment, namely, the level of the output signal is adjusted through the duty ratio, and the working time of the heating unit in the target PWM control signal period is subsequently controlled. For example, a user of the washing machine or the dryer sets a preset temperature to be 50 ℃, the PWM module adopts a switching frequency of 400HZ, the duty ratio of the PWM control signal is set to be 95% of the maximum value at the beginning, the heating unit is prompted to be heated up rapidly, if the current temperature reaches 45 ℃, the duty ratio of the PWM control signal is adjusted to be reduced, the heating speed of the heating unit is prompted to be slowed down, if the current temperature approaches 50 ℃, the duty ratio of the PWM control signal is set to be 5% of the minimum value, the heating speed of the heating unit is prompted to be reduced to the minimum value, and thus the current temperature can be guaranteed to be smoothly increased to 50 ℃ and stably maintained at 50 ℃ until the clothes are washed or dried.

Fig. 10 is a flowchart of a heating control method according to an embodiment of the present application, which is applied to the heating control circuit shown in fig. 2.

Step 1010: and acquiring a preset temperature.

In the embodiment of the present application, step 1010 is the same as step 910, and is not described herein again.

Step 1020: the current temperature of the environment is obtained.

In the embodiment of the present application, step 1020 is the same as step 920, and is not described herein again.

Step 1030: and acquiring the current.

The current of the first loop formed by the power supply unit and the heating unit is obtained through the current sampling unit.

Step 1040: and adjusting the duty ratio of the PWM control signal according to the difference value between the preset temperature and the current to generate a target PWM control signal so as to control the on-time and the off-time of the switch unit, wherein the duty ratio of the target PWM control signal is positively correlated with the difference value between the preset temperature and the current temperature.

Because the difference value between the preset temperature and the current temperature of the environment reflects the condition that the heating unit still needs to generate heat, and the current reflects the current power condition of the heating unit, in the embodiment of the application, the operation or logic judgment module inside the MCU or the CPU adjusts the duty ratio of the PWM control signal according to the difference value between the preset temperature and the current temperature of the environment and the current, that is, adjusts the level of the output signal according to the duty ratio, and then subsequently controls the working duration of the heating unit in the target PWM control signal period. In practical application, the test can be carried out by combining preset temperature, current temperature and current, an optimal PWM control signal duty ratio adjusting function is fitted, the input of the function is the preset temperature and the current temperature, the output of the function is the PWM control signal duty ratio, so that smooth temperature rise and stable heat preservation are realized, and the user experience is improved.

Fig. 11 is a flowchart of a heating control method according to an embodiment of the present application, which is applied to the heating control circuit shown in fig. 3, and the heating control method includes the following steps.

Step 1110: and acquiring a preset temperature.

In the embodiment of the present application, step 1110 is the same as step 910, and is not described herein again.

Step 1120: the current temperature of the environment is obtained.

In the embodiment of the present application, step 1120 is the same as step 920, and is not described herein again.

Step 1130: and acquiring the current.

In the embodiment of the present application, step 1130 is the same as step 930, and is not described herein again.

Step 1140: and acquiring the current voltage.

According to the embodiment of the application, the voltage sampling unit is used for sampling the voltage of the power supply unit to obtain the current voltage.

Step 1150: and adjusting the duty ratio of the PWM control signal according to the difference value of the preset temperature and the current temperature to generate a target PWM control signal so as to control the on-time and off-time of the switch unit, wherein the duty ratio of the target PWM control signal is positively correlated with the difference value.

Because the difference value between the preset temperature and the current temperature of the environment reflects the condition that the heating unit still needs to generate heat, and the current and the current voltage reflect the current power condition of the heating unit, in the embodiment of the application, the operation or logic judgment module inside the MCU or the CPU adjusts the duty ratio of the PWM control signal according to the difference value between the preset temperature and the current temperature of the environment, the current and the current voltage, that is, the level of the output signal is adjusted by the duty ratio, and then the working duration of the heating unit in the target PWM control signal period is subsequently controlled. In practical application, the preset temperature, the current and the current voltage can be combined for testing, an optimal PWM control signal duty ratio adjusting function is fitted, the input of the function is the preset temperature, the current temperature and the current voltage, the output of the function is the PWM control signal duty ratio, so that smooth temperature rise and stable heat preservation are achieved, and user experience is improved.

Fig. 12 is a flowchart of a heating control method according to an embodiment of the present application, which is applied to the heating control circuit shown in fig. 6.

Step 1210: and acquiring a preset temperature.

In the embodiment of the present application, step 1210 is the same as step 910, and is not described herein again.

Step 1220: the current temperature of the environment is obtained.

In the embodiment of the present application, step 1220 is the same as step 920, and is not described herein again.

Step 1230: and selecting the number of paths output by the PWM control subunit and adjusting the duty ratio of the PWM control signal according to the difference value of the preset temperature and the current temperature to generate a target PWM control signal so as to control the on-off duration and the off-off duration of the switch unit, wherein the duty ratio of the target PWM control signal is positively correlated with the difference value of the preset temperature and the current temperature.

In the embodiment of the application, the heating control circuit comprises a multi-path heating subunit, a multi-path switch subunit and a multi-path PWM control subunit. The PWM control unit can select and output several paths of PWM control signals according to the difference value of the preset temperature and the current temperature.

The embodiment of the application provides a heating control method, which includes the steps of selecting the number of paths output by a PWM control subunit and adjusting the duty ratio of a PWM control signal through the difference value between the preset temperature and the current temperature, generating a target PWM control signal, realizing input control on each heating subunit, ensuring smooth rise and stable heat preservation of the temperature in a washing machine or a drying machine, and improving user experience.

The embodiment of the application also provides a washing machine which comprises the heating control circuit.

The embodiment of the application also provides a dryer, which comprises the heating control circuit.

Embodiments of the present application further provide a computer device, which includes a program or instructions, and when the program or instructions are executed, the computer device is configured to execute a heating control method and any optional method provided in embodiments of the present application.

Embodiments of the present application also provide a storage medium, which includes a program or instructions, and when the program or instructions are executed, the program or instructions are used to execute a heating control method and any optional method provided in embodiments of the present application.

Finally, it should be noted that: as will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A heating control circuit is applied to a washing machine or a dryer and is characterized by comprising a heating unit, a temperature measuring unit, a switch unit, a power supply unit, a current sampling unit and a PWM control unit;

the heating unit is used for heating the environment;

the control end of the switch unit is connected with the second end of the PWM control unit, and the output end of the switch unit is connected with the heating unit and is used for being switched on or switched off according to a target PWM control signal so as to control the heating unit to be switched on or switched off;

the current sampling unit is connected in series between the switch unit and the power supply unit and is used for sampling the current of the first loop to obtain the current of the first loop; the current sampling unit is a current transformer;

the first end of the PWM control unit is connected with the temperature measuring unit and used for adjusting the duty ratio of a PWM control signal according to the difference value between the preset temperature and the current temperature and generating the target PWM control signal, wherein the duty ratio of the target PWM control signal is in positive correlation with the difference value; the PWM control unit includes: the microprocessor unit is connected with the temperature measuring unit and used for adjusting the duty ratio of a PWM control signal according to the difference value between the preset temperature and the current to generate an original PWM control signal, wherein the duty ratio of the original PWM control signal is positively correlated with the difference value; the optical coupling isolation unit is connected with the microprocessor unit at one end and the switch unit at the other end, is used for carrying out level conversion on the original PWM control signal to generate the target PWM control signal, and is used for electrically isolating the microprocessor unit from the switch unit; the level overturning unit is connected in series between the microprocessor unit and the optical coupling isolation unit and is used for carrying out level overturning on the original PWM control signal; the optical coupling isolation unit is also used for carrying out level conversion on the overturned original PWM control signal to generate the target PWM control signal;

the heating unit comprises N paths of heating subunits, wherein N is more than or equal to 1;

the PWM control unit comprises N paths of PWM control subunits, and the PWM control subunits correspond to the switch subunits one to one;

the PWM control unit is further used for determining the number of paths of the PWM control subunit according to the difference value between the preset temperature and the current temperature, wherein the larger the difference value between the preset temperature and the current temperature is, the more the number of paths of the PWM control subunit is opened, and the larger the duty ratio of the PWM control signal is.

2. The heating control circuit according to claim 1, wherein a third terminal of the PWM control unit is connected to the current sampling unit, and the PWM control unit is further configured to generate the target PWM control signal according to the current temperature and the current to drive the switching unit to be turned on or off.

3. The heating control circuit of claim 2, further comprising:

and the fourth end of the PWM control unit is connected with the voltage sampling unit, and the PWM control unit is also used for generating the target PWM control signal according to the current temperature, the current and the current voltage so as to drive the switch unit to be switched on or switched off.

4. The heating control circuit according to any one of claims 1 to 3, wherein the switching unit is a MOS transistor or an IGBT.

5. A heating control method applied to the heating control circuit according to any one of claims 1 to 4, the heating control method comprising:

acquiring a preset temperature;

acquiring the current temperature and current of the environment;

selecting the number of paths output by the PWM control subunit according to the difference value between the preset temperature and the current temperature, adjusting the duty ratio of a PWM control signal according to the difference value between the preset temperature and the current, and generating an original PWM control signal, wherein the larger the difference value between the preset temperature and the current temperature is, the more the number of paths of the output PWM control subunit is, and the larger the duty ratio of the PWM control signal is;

and performing level conversion on the original PWM control signal to generate a target PWM control signal so as to control the closing time length and the opening time length of the switching unit, wherein the duty ratio of the target PWM control signal is positively correlated with the difference value.

6. A washing machine, characterized in that it comprises a heating control circuit according to any one of claims 1 to 4.

7. A dryer, characterized in that it comprises a heating control circuit according to any one of claims 1 to 4.