1. Principle of induction cooker
The principle of induction cooker is as shown in the figure. It uses high-frequency current to circulate the coil inside the cooker
(1) According to the working principle of the induction cooker, the physical knowledge that may be involved in the use of the induction cooker is: the magnetic effect of current, the thermal effect of current (Joule heat), impedance (resistance), magnetic field, magnetization, magnetic induction lines, electromagnetic induction, and energy conversion. , molecular thermal motion, heat transfer, internal energy, molecular current, induced current, eddy current. (2) Because the pot produces current, the thermal effect of the current generates heat, so the heat is generated in the pot, so the heat is transferred from the pot to the furnace , when the induction cooker is working, it consumes electrical energy and converts it into internal energy; when steaming steamed buns, you need to boil water. The water boils to generate steam. The steam transfers heat to the steamed buns to steam them. Steaming one steamed bun takes the same time as steaming 5 steamed buns. , both are 25min. (3) Take the lowest thermal efficiency of 90, and the lowest temperature adjustment is 100°C. Within the range of power adjustment and temperature adjustment of the induction cooker, the heating temperature changes with the power adjustment in a linear relationship. At this time, the actual power consumed by the induction cooker P There is the following relationship with the heating temperature t temperature: t temperature?70℃P?450W=240℃?70℃1600W?450W ①It can be obtained: t temperature=17℃115W(P-450W) 70℃, when t temperature= At 100℃, P=653W ②Heat absorbed by water: Q absorption=cm(t temperature-t0)=4.2*103J/(kg?℃)*3kg*(100℃-22℃)=9.828*105J. Induction cooker work Energy absorbed by water: W=Ptη, the heat generated by the induction cooker is equal to the heat absorbed by the water, W=Q absorption=Ptη, the heating time of the induction cooker: t=WPη=9.828*105J653W*90≈1672s; ④So the answer is: ( 1) The magnetic effect of current, the thermal effect of current (Joule heat), impedance (resistance), magnetic field, magnetization; (2) Pot; induction cooker; electricity; internal; (3) Boil a pot of mass under 1 standard atmospheric pressure Water with a temperature of 3kg and a temperature of 22°C takes up to 1672s.
How does an induction cooker work?
The induction cooker uses the principle of magnetic field induction eddy current heating. It uses current to pass through the coil to generate a magnetic field. When the magnetic force in the magnetic field passes through the bottom of the iron-containing pot, countless small eddy currents will be generated, causing the pot itself to It generates heat at high speed and then reheats the food in the pot. The electromagnetic waves generated by the induction cooker are completely absorbed by the shielding layer at the bottom of the coil and the iron-containing pot on the top plate.
Induction cooker heating principle
Induction cooker uses the principle of electromagnetic induction to heat food. The surface of the induction cooker is a heat-resistant ceramic plate. The alternating current passes through the coil under the ceramic plate to generate a magnetic field. When the magnetic field lines in the magnetic field pass through the bottom of iron pots, stainless steel pots, etc., eddy currents are generated, causing the bottom of the pot to heat up quickly, achieving the desired effect of heating food. Purpose. The working process is as follows: AC voltage is converted into DC power through a rectifier, and the DC power is turned into high-frequency AC power that exceeds the audio frequency through a high-frequency power conversion device. The high-frequency AC power is applied to the flat hollow spiral induction heating coil, resulting in High frequency alternating magnetic field. Its magnetic field lines penetrate the ceramic plate of the stove and act on the metal pot. Strong eddy currents are generated in the cooking pot due to electromagnetic induction. When the eddy current overcomes the internal resistance of the pot and flows, it completes the conversion of electrical energy into thermal energy. The Joule heat generated is the heat source for cooking.
What is the principle of induction cooker
The principle of induction cooker
When a loop coil is supplied with current, its effect is equivalent to a magnet bar. Therefore, the N-S pole of the magnetic field is generated on the coil surface, that is, there is magnetic flux passing through it. If the power source used is alternating current, the magnetic poles of the coil and the magnetic flux crossing the return surface will change.
When a magnetically conductive metal surface is placed above the loop coil, the metal surface will induce current. Because there is resistance on the metal surface, the induced current will cause the metal surface to generate heat energy, and this heat energy is used to cook the food.
The greater the current induced, the higher the heat generated and the shorter the time required to cook the food. To make the induced current larger, the change in magnetic flux passing through the metal surface will be larger, and of course the magnetic field intensity will be stronger. As a result, the coil originally supplied with alternating current needs more turns to be wound together.
Because it uses high-intensity magnetic field induction, no current is generated on the stove surface, so the stove surface will not generate high temperatures when cooking food. It is a relatively safe cooking appliance.
Working Principle of Induction Cooker
Working Principle and Structure of Induction Cooker - Section Working Principle of Induction Cooker Induction cooker is mainly a kitchen appliance that uses the principle of electromagnetic induction to convert electrical energy into heat energy. When the induction cooker is working normally , the rectifier circuit converts the 50Hz AC voltage into a DC voltage, and then the control circuit converts the DC voltage into a high-frequency voltage with a frequency of 20-40KHz. The alternating magnetic field will be generated on the coil plate of the induction cooker and will repeatedly cut and change at the bottom of the pot. , causing a ring current (eddy current) to be generated at the bottom of the pot, and using the short-circuit heating effect of small resistance and large current to generate heat to directly heat the bottom of the pot quickly, and then heat the contents of the utensil.
This oscillating heating method can reduce the intermediate links in heat transfer and greatly improve heating efficiency. The block diagram of the electric control working principle of the induction cooker is as follows: AC power supply LC oscillation circuit power control bridge rectifier temperature adjustment power drive circuit waveform generation circuit overvoltage detection circuit pot detection circuit main control IC circuit step-down rectification circuit temperature detection circuit current adjustment. Chapter 1 Section 2. Indication of the model and article number of the induction cooker 1. Indication of the model of the induction cooker M——Midea C——Induction cooker 1. As for the ceramic plate: P——indicates that the surface of the ceramic plate is a plane A——indicates the surface of the ceramic plate It is a concave surface. 2. In terms of display mode: V——represents VFD display.
That is fluorescent color display (high-end series) C - means LCD display. That is, blue screen LCD display (mid-range series) S——represents digital display.
That is, digital tube display (mid-range series) Vacancy - means no display function (low-end series) 3. In terms of the shape of the ceramic panel: Y - means the panel is round (Y: yuan circle) F ——Indicates that the panel is square. 4. Power description: It consists of two digits. The data * 100 is the maximum power of the induction cooker. For example: 08——indicates the maximum power is 800W; 16——indicates the maximum power is 1600W5. Equipment distinction codes: A, B, C, D are used to distinguish different induction cookers in the same series (Note: The new product PSF series products will be launched as soon as possible , temporarily using the certification of the old PSD, so this series of products retains the PSD code)
Coding example: MC - PVF20A M - MIDEA; C - induction cooker; P - flat ceramic plate; V——VFD display mode; F——square ceramic panel; 20——maximum power is 2000W; A——A model; 2. Induction cooker product number representation method 1 22 Y V: ① Product display characteristic code: one letter represents, represents Product display characteristics are also the distinction between grades. V: VFD display ------ the highest-end product (single furnace) C: LCD display ------- high-end product S: digital display ------- mid-range product E: LED display --- ---- Low-end induction cooker ② Ceramic plate shape characteristics: one letter represents the appearance characteristics of the product.
Y---round ceramic plate F---square ceramic plate ③Product power characteristic code: two-digit representation, representing 1/100 of the power of the induction cooker. For example: 22 represents an induction cooker with a power of 2200w. ④ Product identification code: in digital form, distinguishing different products.
"1, 2, 3..." and so on. Section 3 Introduction and functions of the main components of the induction cooker\ Midea induction cooker is mainly composed of the following components: 1. Power cord 2. Fan 3. Coil plate 4 , Transformer 5, thermistor 6, ceramic plate 7, bottom seat 8, upper cover, 9, electronic control board! The functions and characteristics of each component are described below: 1. Power cord: Function: It is to introduce external mains power into the induction cooker. Since the power consumption of the induction cooker is relatively large, the overcurrent capability of the power cord is required to be relatively strong. If the wire core If the diameter is too small, the power cord will heat up, and the outer cover will become hard or even burnt after long-term use. Features: The core diameter of the existing power cord of Midea induction cooker is 1.0mm2, which can carry a current of 10A.
2. Fan function: The fan is a component that dissipates heat in the induction cooker. Currently, there are three types of fans: 1 brushed fan and 2 brushless fans; brushless fans are divided into 12V and 18V.
Features: Brushless fans are more durable, have larger air volume and lower noise; the noise source of brushed fans is mainly airflow sound. 3. Coil disk function: In the induction cooker, it is one of the key devices to complete LC oscillation, a device to store and release electrical energy, and a key device to complete the conversion of electric field energy into magnetic field energy.
In the circuit principle, it is generally analyzed as an inductor, which is divided into two types: large coil disk and small coil disk. There are two types of inductance: 140uH and 157uH. Features: National patented large coil plate, ensuring 100% heating area at the bottom of the pot, more uniform heating, and higher thermal efficiency 4. Transformer function: It is a device that converts 220V AC power into low-voltage AC power. Generally, there are two or three sets of power supplies on the induction cooker. , 5V, 18V, the three sets of power supplies also include 12V. Those that use two sets of power supplies generally use 5V for microcontrollers, display buttons and some low-voltage processing circuits, and 18V for IGBT drive or fan power. Those that use three sets of power supplies generally use IGBT drive and The fan power supply is separated and the fan power supply adopts 12V.
The transformer provides front-stage low-voltage AC for the above power supply. Therefore, transformers generally have three sets of power supplies.
Features: Midea uses hot-rolled silicon steel sheet transformers to reduce the power loss and heat of the transformer and extend its service life. 5 Thermistor function: senses the heating temperature of the pot and transmits the signal to the control loop and main control IC Through judgment, the working process of the induction cooker is controlled. Features: Made of negative temperature coefficient material, imported quality.
6. Ceramic plate function: on the outermost surface of the induction cooker, it determines the appearance quality of the induction cooker. It is divided into two categories: domestic and imported. Domestic is divided into glazed and unglazed. Generally speaking, , after glazing, it is not easy to turn yellow. Features: In the heated state, the expansion coefficient is extremely small, radial heat transfer, high temperature resistance, and wear resistance.
Imported ceramic plate: white. Domestic ceramic plates: A, B, C and glazed.
7. Bottom seat 8. Upper cover Function: The plastic upper cover and base together form the product protective shell. Features: Midea induction cooker is made of V0 flame-retardant grade antibacterial, mildew, and UV-resistant plastic, and has an antibacterial rate of 99.89 certified by authoritative departments.
Double-layer metal spraying process on the surface: Spraying protective paint on the surface greatly improves the coating's scratch resistance. 9. Electric control board function: The key component of the induction cooker has nearly 200 components.
There are the following modules on the circuit board: power entry EMC protection module; rectifier module; filter module; LC oscillation module; IGBT switch module; zero-crossing detection module; current detection module; voltage detection module; temperature detection module ; Synchronization module; Oscillation control module; IGBT drive module; Power.
Read the passage and answer the questions that follow. As shown in the figure is a schematic diagram describing the principle of the induction cooker. Stove
(1) According to "Because the induction cooker generates current through electromagnetic induction, it uses The electric heating effect generates heat, so not all pots or utensils are suitable." It can be seen that the heating effect of current is used here; according to "The method for choosing a pot is very simple, as long as the bottom of the pot can attract a magnet, it can be used." The magnetic effect of current is used here; (2) Because ceramics and glass are generally neither magnetic nor electrically conductive, no induced current will be generated in a magnetic field. Aluminum and copper are not magnetically conductive materials, so induction cookers cannot be used. Pots made of these two materials. (3) Because the magnetic field lines can pass through cardboard. The iron pot has enough magnetic field lines to pass through, so the induction cooker can work normally. So the answer is: (1) The heating effect of current; Magnetic effect of current; (2) Answer: Because ceramics and glass are generally neither magnetic nor electrically conductive, no induced current will be generated in a magnetic field. Aluminum and copper are not magnetically conductive materials, so these two cannot be used in induction cookers. Pots made of various materials; (3) Answer: Because the magnetic field lines can pass through cardboard. The iron pot has enough magnetic field lines to pass through, so the induction cooker can work normally.