Electric kettle circuit system with multiple intelligent control functions

Abstract

The utility model discloses a kind of electric kettle circuit systems with multiple intelligent control function, it is related to the field of household appliances, including main control module, temperature detection module, heating control module, dry-burning protection module, lift pot detection module and intelligent interaction module.By integrating STM32 single-chip microcomputer, DS18B20 sensor, barometric calibration, photoelectric sensing and Wi-Fi module, high-precision temperature control, multiple dry-burning protection, intelligent lifting pot detection and remote interaction function are realized.The utility model solves the problems of low temperature control precision, single dry-burning mechanism, lack of intelligent interaction and unreliable lifting pot detection in the prior art, and is suitable for smart home scenarios.

Description

Technical Field

[0001] This utility model relates to the field of household appliance technology, specifically to a circuit system for an electric kettle, which is particularly suitable for electric kettles with intelligent temperature control, anti-dry burning, kettle lifting detection and remote control functions. Background Technology

[0002] The circuit design of existing electric kettles generally has the following shortcomings:

[0003] 1. Insufficient temperature control accuracy: Traditional thermostats rely on bimetallic strips or steam sensors, which are easily affected by factors such as ambient temperature and altitude, resulting in inaccurate boiling point control and problems such as continuous boiling causing water spraying or energy waste.

[0004] 2. Limited anti-dry-burning mechanism: Most products rely solely on the bottom thermostat. If the thermostat fails or is covered with limescale, it may lead to the risk of dry burning.

[0005] 3. Lack of intelligent interaction: It cannot achieve remote control, status monitoring and personalized temperature setting, making it difficult to meet the needs of modern smart homes.

[0006] 4. Low reliability of kettle lifting detection: Traditional temperature sensing bulbs or mechanical switches have delayed response, which can easily lead to water pump leakage or coupler short circuit. Utility Model Content

[0007] Purpose of the invention

[0008] The present invention aims to provide an electric kettle circuit system that integrates multiple intelligent control functions, solving the problems of low temperature control accuracy, simple anti-dry-boil mechanism, lack of intelligent interaction, and unreliable kettle lifting detection in the prior art.

[0009] Technical solution

[0010] An electric kettle circuit system with multiple intelligent control functions includes:

[0011] Main control module: The STM32F103C8T6 microcontroller is used as the core controller, which integrates the ARM Cortex-M3 core and supports high-speed data processing and multi-task parallel operation.

[0012] Temperature detection module: Employs a DS18B20 digital temperature sensor to monitor water temperature in real time with an accuracy of ±0.5℃, supporting multi-point temperature sampling (bottom of the kettle, kettle wall, steam outlet). Built-in barometric pressure sensor (e.g., BMP280) automatically calibrates the boiling point value based on altitude, allowing users to customize the boiling point range (80-100℃) via adjustment modules.

[0013] Heating control module: Employs bidirectional thyristors (such as BT136) for power regulation, combined with a PID algorithm to dynamically adjust heating power, and supports half-wave heating mode to reduce standby power consumption. Relays (such as G5V-1) control the main heating circuit, providing overcurrent protection and fault self-diagnosis functions.

[0014] Anti-dry-burning protection module: A pressure sensor (such as HX711) detects the water level in the kettle. When the water level is below the threshold, it triggers an audible and visual alarm and cuts off the heating. The bottom thermostat (KSD301) is linked with the MCU and forces a power cut-off when the temperature exceeds 110℃.

[0015] The kettle lifting detection module uses a photoelectric sensing component (LED + phototransistor) that works in conjunction with a ring at the bottom of the kettle. Lifting the kettle triggers a signal, immediately stopping the water pump and heating in the main control module. A Hall effect sensor monitors the coupling state between the kettle and its base to prevent accidental operation.

[0016] Intelligent Interaction Module: The Wi-Fi module (such as ESP8266) connects to the cloud platform via the MQTT protocol, supporting remote control via mobile APP (temperature setting, scheduled water boiling, status query). The OLED display (0.96-inch) displays water temperature, boiling point, working mode, and fault codes in real time. The voice recognition module (such as LD3320) supports voice command control ("Start boiling water", "Keep warm at 50℃").

[0017] Detailed connection relationships between the main control module and each functional module:

[0018] I. Connection between the main control module and the temperature detection module:

[0019] Core components: The main control module uses an STM32F103C8T6 microcontroller, and the temperature detection module includes a DS18B20 digital temperature sensor and a BMP280 barometric pressure sensor.

[0020] Specific link:

[0021] DS18B20 and STM32:

[0022] The DATA pin (single-bus data output) of the DS18B20 is directly connected to the PA0 pin (input mode) of the STM32 to transmit real-time water temperature data through the single-bus protocol. The STM32 sends reset and read / write commands and receives temperature values ​​through this pin.

[0023] BMP280 and STM32:

[0024] BMP280's SCL pin (I 2 The C clock input terminal is connected to the STM32's PB6 pin (output mode) to receive the synchronous clock signal sent by the STM32;

[0025] BMP280's SDA pin (I 2 The C data input / output terminal is connected to the PB7 pin of the STM32 (bidirectional mode) to realize bidirectional transmission of air pressure and temperature data (STM32 is the master device and BMP280 is the slave device).

[0026] II. Connection between the main control module and the heating control module:

[0027] Core components: The heating control module includes a bidirectional thyristor BT136 (isolated by an optocoupler MOC3021) and a relay G5V-1 (driven by an NPN transistor S8050).

[0028] Specific link:

[0029] Optocoupler MOC3021 and STM32:

[0030] The optocoupler input terminal (the anode is connected to a current-limiting resistor and then to a 5V power supply, and the cathode is connected to the PA1 pin of the STM32) allows the STM32 to output a PWM pulse signal (duty cycle adjustable) through PA1 to control the conduction state of the optocoupler, thereby adjusting the conduction angle of the bidirectional thyristor and realizing stepless adjustment of the heating power.

[0031] Relay driver circuit and STM32:

[0032] The base of the NPN transistor S8050 (via a 1kΩ current-limiting resistor) is connected to the PA2 pin (output mode) of the STM32. When the STM32 outputs a high level, the transistor is saturated and conducting, the relay coil is energized and engaged, and the heating main circuit is connected; when the output is low, the transistor is cut off, the relay is disconnected, and heating stops.

[0033] III. Connection between the main control module and the anti-dry-burning protection module:

[0034] Core components: The anti-dry-burning protection module includes an HX711 pressure sensor (with a weighing probe) and a KSD301 thermostat (normally closed contact).

[0035] Specific link:

[0036] HX711 and STM32:

[0037] The HX711's DOUT pin (data output) is connected to the STM32's PA3 pin (input mode) to output the digital conversion result of the weight analog signal;

[0038] The SCK pin (clock input) of the HX711 is connected to the PA4 pin (output mode) of the STM32 to receive the clock signal sent by the STM32 for synchronous data transmission. When the water level in the kettle is detected to be less than 50ml, the HX711 outputs a low level through the DOUT pin to trigger protection.

[0039] KSD301 and STM32:

[0040] The normally closed contact output of the KSD301 is connected in series with a 10kΩ pull-up resistor and then connected to the PA5 pin of the STM32 (input mode, configured as an external interrupt). During normal operation, the contact is closed and the PA5 pin is low. When dry burning occurs, the contact is open and the PA5 pin jumps to a high level, triggering the STM32 interrupt service routine and immediately cutting off the heating circuit.

[0041] IV. Connection between the main control module and the kettle detection module:

[0042] Core components: The kettle detection module includes photoelectric sensing components (light-emitting diode + phototransistor) and Hall sensor (A3144).

[0043] Specific link:

[0044] Photoelectric sensing components and STM32:

[0045] The emitter (voltage output terminal) of the phototransistor is connected to the PA6 pin (analog input mode) of the STM32. The LED is powered by a 3.3V constant current source (independent circuit). When the pot is lifted, the light path is blocked, the phototransistor is cut off, and the PA6 pin detects a high level. When the pot is put back, the light path is turned on, the phototransistor is turned on, and the PA6 pin detects a low level (voltage < 0.5V).

[0046] Hall effect sensor and STM32:

[0047] The Hall sensor's DO pin (digital output) is connected to the STM32's PA7 pin (input mode). When the pot (containing the magnet) is placed in position, the Hall element outputs a low level due to the magnetic field. When the pot is lifted, the magnetic field disappears, and the output becomes high. This dual detection, combined with the photoelectric signal, avoids misjudgment by a single sensor.

[0048] V. Connection between the main control module and the intelligent interaction module:

[0049] Core components: The intelligent interaction module includes an ESP8266 Wi-Fi module, an OLED display (12864), and an LD3320 voice recognition module.

[0050] Specific link:

[0051] ESP8266 and STM32:

[0052] The TX pin (data output) of the ESP8266 is connected to the PB11 pin (UART3 receiver) of the STM32, and the RX pin (data input) of the ESP8266 is connected to the PB10 pin (UART3 transmitter) of the STM32. The UART protocol enables bidirectional transmission of mobile APP commands (such as starting heating and adjusting temperature) and device status (such as current water temperature and working mode). The baud rate is set to 115200.

[0053] OLED display and STM32:

[0054] OLED SCL pin (I 2 The C clock input terminal is connected to the STM32's PB8 pin (output mode), and the SDA pin (I) is connected to the STM32's clock input terminal. 2 The C data input terminal is connected to the STM32's PB9 pin (output mode). The STM32 connects via I... 2 The C protocol sends display data (such as set temperature and heat preservation time) to drive the OLED to refresh the interface in real time.

[0055] LD3320 and STM32:

[0056] The SCK pin (SPI clock input) of the LD3320 is connected to the PC10 pin (output mode) of the STM32, the MOSI pin (SPI data input) is connected to the PC11 pin (output mode) of the STM32, the MISO pin (SPI data output) is connected to the PC12 pin (input mode) of the STM32, and the CS pin (chip select input) is connected to the PC9 pin (output mode) of the STM32. The STM32 sends voice recognition commands (such as "heat to 80℃") via the SPI protocol and receives the recognition results from the LD3320 (the operation is executed when the matching degree is >90%).

[0057] Additional notes:

[0058] Signal isolation: The high voltage circuit (220V) of the heating control module and the low voltage circuit (3.3V / 5V) of the STM32 are physically isolated through optocoupler MOC3021 and relay to avoid high voltage interference to the main control chip.

[0059] Power matching: All module power pins are powered by LDO regulator chips (such as AMS1117-3.3) to ensure that the input voltage of STM32 is stable at 3.3V±0.1V, and the power fluctuation of sensors and actuators is controlled within ±5%.

[0060] Anti-interference design: critical signal lines (such as I) 2Both the C and SPI buses have a 100Ω current-limiting resistor in series and a 100nF filter capacitor in parallel to reduce the impact of electromagnetic interference (EMI) on data transmission.

[0061] Beneficial effects

[0062] (1) High-precision temperature control: Combining the DS18B20 sensor, air pressure calibration and PID algorithm, the temperature control accuracy is ±1℃, avoiding the risk of continuous boiling and water spraying.

[0063] (2) Multiple anti-dry burning protection: pressure sensor, bottom thermostat and water level monitoring triple mechanism, response time <0.5 seconds, effectively prevents dry burning.

[0064] (3) Intelligent interactive experience: Supports remote control via APP, voice commands and cloud data storage to meet personalized needs.

[0065] (4) Improved reliability of kettle lifting detection: dual detection by photoelectric induction and Hall sensor, response time <0.1 seconds, avoiding water pump leakage and coupler short circuit.

[0066] (5) Energy saving optimization: Half-wave heating mode reduces standby power consumption to <1W, and dynamic power adjustment improves energy efficiency ratio by 20%. Attached Figure Description

[0067] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0068] Figure 1 This is a circuit system architecture diagram of the present invention (connection relationship of main control module, temperature detection module, heating control module, anti-dry burning protection module, kettle lifting detection module, and intelligent interaction module);

[0069] Figure 2 This is the circuit diagram of the temperature detection module of this utility model (connection method of DS18B20 and STM32);

[0070] Figure 3 This is a circuit diagram of the heating control module of this utility model (driving circuit of bidirectional thyristor and relay);

[0071] Figure 4 This is a circuit diagram of the kettle detection module of this utility model (signal processing circuit of photoelectric sensing component and Hall sensor);

[0072] Figure 5 This is a schematic diagram of the intelligent interaction module of this utility model (communication process between the Wi-Fi module and the cloud platform).

[0073] Attached reference numerals: 1. Main control module; 2. Temperature detection module; 3. Heating control module; 4. Anti-dry-boil protection module; 5. Lifting kettle detection module; 6. Intelligent interaction module. Detailed Implementation

[0074] Please see Figure 1-5 This utility model provides a technical solution: an electric kettle circuit system with multiple intelligent control functions, comprising:

[0075] Main control module 1, temperature detection module 2, heating control module 3, anti-dry-boil protection module 4, kettle lifting detection module 5, and intelligent interaction module 6;

[0076] The main control module 1 is electrically connected to the temperature detection module 2, the heating control module 3, the anti-dry-boil protection module 4, the kettle lifting detection module 5, and the intelligent interaction module 6.

[0077] Temperature detection module 2 includes a DS18B20 temperature sensor and a pressure sensor. Temperature detection module 2 supports multi-point temperature sampling of the bottom of the kettle, the kettle wall, and the steam outlet, and automatically calibrates the boiling point value through the pressure sensor.

[0078] Heating control module 3 includes a bidirectional thyristor and a relay. Heating control module 3 uses a PID algorithm to dynamically adjust the heating power and supports half-wave heating mode to reduce standby power consumption.

[0079] The anti-dry-burning protection module 4 includes a pressure sensor and a bottom thermostat. The anti-dry-burning protection module 4 detects the water level through the pressure sensor. When the water level is lower than the threshold, it triggers an alarm and cuts off the heating.

[0080] The kettle lifting detection module 5 includes a photoelectric sensing component and a Hall sensor. The kettle lifting detection module 5 cooperates with the ring plate at the bottom of the kettle body through the photoelectric sensing component. When the kettle is lifted, a level signal is triggered, and the main control module immediately stops the water pump and heating.

[0081] The intelligent interaction module 6 includes a Wi-Fi module and an OLED display screen; the intelligent interaction module 6 connects to the cloud platform via the Wi-Fi module, supporting remote control via mobile APP and voice command operation.

[0082] Hardware implementation:

[0083] 1. The main control module connects to the barometric pressure sensor (BMP280) via the SPI interface and to the DS18B20 sensor via the single-bus protocol.

[0084] 2. The heating control module uses a bidirectional thyristor to achieve 0-100% power regulation, and a relay controls the on / off state of the main circuit.

[0085] 3. The photoelectric sensing component of the pot lifting detection module is installed on the base. When the bottom ring plate of the pot is blocked, it outputs a low level signal and triggers a high level signal when the pot is lifted.

[0086] Software implementation:

[0087] 1. Temperature control algorithm: An incremental PID algorithm is adopted with a sampling period of 100ms, and the heating power is dynamically adjusted according to the water temperature deviation.

[0088] 2. Anti-dry burning logic: The pressure sensor monitors the water level in real time and triggers an alarm when the water level is <50ml; the bottom thermostat will force a power cut-off when the temperature is >110℃.

[0089] 3. Intelligent Interaction: The Wi-Fi module uploads data to the cloud via the MQTT protocol, and the APP supports historical data query and fault diagnosis.

[0090] Basic principles of PID algorithm:

[0091] The PID algorithm outputs a control quantity (u(t)) by performing proportional, integral, and derivative operations on the deviation (e(t)) between the current system state and the target state. The formula is as follows: u(t) = K p e(t)+K i ∫ 0t e(τ)dτ+K ddtde(t) in:

[0092] K p K is the proportionality coefficient, reflecting the immediate adjustment effect of the deviation. p It can speed up the response, but it is prone to overshoot and oscillation;

[0093] K i The integral coefficient is used to eliminate steady-state deviations. Excessive integral action will slow down the system response and increase overshoot.

[0094] K d The differential coefficient can predict the trend of deviation changes, suppress overshoot, and accelerate system convergence. However, excessive differential action is easily affected by noise.

[0095] Specific applications of this technical solution:

[0096] (I) Definition of Controlled Objects and Deviations:

[0097] In this patent, a target parameter, such as a set water temperature T, is used. set Set pressure P set The target value is set as the real-time acquisition of actual parameters, such as the actual water temperature T, through sensors such as the DS18B20 temperature sensor and pressure sensor. real Actual pressure P real The deviation target value is defined as the actual collected value, i.e., e(t) = T.set -T real (Taking water temperature control as an example, the same principle applies to other controlled objects.)

[0098] (II) The relationship between the algorithm and the hardware module:

[0099] Data acquisition input: The actual parameters collected by the sensor (such as the DS18B20 temperature sensor, pressure sensor, etc.) are converted into a processable electrical signal by the signal conditioning circuit (if any) and input to the main control chip (such as STM32F103C8T6). This provides the basis for the main control chip to calculate the deviation e(t) and is the input source of the PID algorithm.

[0100] Algorithm Execution: The main control chip, as the core computing unit, has a built-in PID algorithm program. Based on the collected deviation e(t), it executes the algorithm according to the PID formula, combined with a pre-tuned K... p K i K d The coefficient is used to calculate the output control quantity u(t) in real time.

[0101] Control output execution: The control quantity u(t) output by the main control chip acts on the actuator (such as a heating control module composed of a bidirectional thyristor and a relay, or other adjustment modules). Taking heating control as an example, the control quantity can adjust the heating power, heating time, etc., thereby changing the actual parameters (water temperature, pressure, etc.) to form a closed-loop control.

[0102] (III) Parameter Tuning and Optimization:

[0103] For the specific application scenario of this system, experimental methods such as the step response method and the Ziegler-Nichols method were used to study K. p K i K d Perform the adjustment:

[0104] proportionality coefficient K p Initially, use an empirical value, such as 0.5-2, and adjust it according to the actual scenario. Observe the system response speed and overshoot. If the response is slow, increase K. p If the overshoot is large, then decrease K. p ;

[0105] Integral coefficient K i Initially, use an empirical value, such as 0.01-0.1, and adjust it according to the actual scenario. If steady-state deviations remain, appropriately increase K. i If the system exhibits integral saturation or excessive overshoot, reduce K. i Or increase the points limit;

[0106] Differential coefficient K dInitially, use an empirical value, such as 0.1-1, and adjust it according to the actual scenario. If the system oscillates or converges slowly, increase K. d To suppress oscillations, if there is severe noise interference, decrease K. d Alternatively, a filtering step can be added.

[0107] Through testing and optimization, this patent allows for the determination of PID parameters for specific controlled objects, such as water temperature control, enabling the system to achieve excellent results in control indicators such as heating time, steady-state error, and overshoot.

[0108] IV. Advantages and Effects:

[0109] (a) Improved control precision:

[0110] By continuously adjusting the deviation through the PID algorithm, compared with traditional open-loop control or simple feedback control, the steady-state error can be greatly reduced, so that the controlled object, such as water temperature and pressure, is stabilized near the target value, and the error is controlled within a very small range, such as ±0.5℃, ±0.1kPa, etc., which meets the high precision requirements of this patent for system functions such as precise temperature control and pressure stability.

[0111] (II) System Response and Stability Optimization:

[0112] The proportional element accelerates the response speed, the derivative element suppresses overshoot and enhances stability, and the integral element eliminates steady-state deviation. The three elements work together to enable the system to respond quickly and operate stably when faced with external disturbances, such as changes in ambient temperature or load, avoiding large fluctuations or long-term deviations from the target value, thus improving the reliability and practicality of the system.

[0113] (III) Adapting to control requirements in multiple scenarios:

[0114] The parameters of the PID algorithm can be flexibly adjusted according to different application scenarios, such as different altitudes (affecting air pressure and boiling point) and different initial water temperatures, by retuning K. p K i K d This allows it to adapt to diverse environments and usage needs, expanding the scope of application of this patented technology and enhancing the versatility and robustness of the product.

[0115] In summary, the PID algorithm serves as the core control strategy in this patented technical solution. Through precise deviation adjustment, efficient collaboration with hardware modules, and flexible parameter adaptation, it effectively ensures the control performance of the system.

[0116] Experimental data:

[0117] 1. Temperature control accuracy test:

[0118] (1) Test environment: room temperature 25℃, altitude 0m (standard atmospheric pressure), altitude 1500m (low atmospheric pressure).

[0119] (2) Test method: Set the target temperature to 80℃, 90℃, and 100℃, and record the actual stable water temperature (n=10 times).

[0120] (3) Results:

[0121]

[0122] 2. Anti-dry-burning response time test:

[0123] (1) Test conditions: Simulated dry boiling (water volume in the kettle < 50ml), thermostat failure (short circuit).

[0124] (2) Results:

[0125] (3) Pressure sensor trigger protection: response time 0.3±0.1 seconds.

[0126] (4) Bottom temperature controller (KSD301) trigger protection: response time 0.4±0.1 seconds.

[0127] (5) Dual protection linkage: maximum power failure delay < 0.5 seconds.

[0128] 3. Reliability test for the kettle:

[0129] (1) Test method: 1000 times of lifting / putting back the pot, and record the number of false triggers.

[0130] (2) Results:

[0131] (3) Photoelectric induction + Hall sensor combination: 0 false triggers.

[0132] (4) Single mechanical switch (traditional solution): 23 false triggers.

[0133] 4. Energy consumption comparison test:

[0134] (1) Test object: the circuit of this utility model vs the traditional electric kettle circuit.

[0135] (2) Results:

[0136]

[0137] 5. Intelligent Interaction Delay Test:

[0138] (1) Test content: Response time of remote commands from mobile APP (start heating, stop heating).

[0139] (2) Results:

[0140] (3) When the Wi-Fi connection is stable: command response delay < 1 second.

[0141] (4) When the network fluctuates (packet loss rate 10%): maximum delay < 3 seconds.

[0142] in conclusion:

[0143] The circuit system of this invention is superior to traditional solutions in terms of temperature control accuracy, safety protection response speed, energy consumption, and intelligent interaction performance, thus meeting the design objectives.

[0144] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A circuit system for an electric kettle with multiple intelligent control functions, characterized in that, include: The main control module (1), temperature detection module (2), heating control module (3), anti-dry-burning protection module (4), kettle lifting detection module (5), and intelligent interaction module (6) are included. The main control module (1) is electrically connected to the temperature detection module (2), the heating control module (3), the anti-dry-burning protection module (4), the kettle detection module (5), and the intelligent interaction module (6); The temperature detection module (2) includes a DS18B20 temperature sensor and a pressure sensor; the heating control module (3) includes a bidirectional thyristor and a relay; the anti-dry-burning protection module (4) includes a pressure sensor and a bottom thermostat; the kettle lifting detection module (5) includes a photoelectric sensing component and a Hall sensor; and the intelligent interaction module (6) includes a Wi-Fi module and an OLED display screen.

2. The electric kettle circuit system with multiple intelligent control functions according to claim 1, characterized in that: The temperature detection module (2) samples the temperature through the bottom of the kettle, the kettle wall or the steam outlet, and calibrates the boiling point value through a pressure sensor.

3. The electric kettle circuit system with multiple intelligent control functions according to claim 1, characterized in that: The heating control module (3) uses a PID algorithm to dynamically adjust the heating power.

4. The electric kettle circuit system with multiple intelligent control functions according to claim 1, characterized in that: The anti-dry-burning protection module (4) detects the water volume through a pressure sensor.

5. The electric kettle circuit system with multiple intelligent control functions according to claim 1, characterized in that: The pot-lifting detection module (5) triggers a level signal by cooperating with the bottom ring plate of the pot body through the photoelectric sensing component.

6. The electric kettle circuit system with multiple intelligent control functions according to claim 1, characterized in that: The intelligent interaction module (6) is connected to the cloud platform via a Wi-Fi module.

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