1. Introduction of circuit structure of induction cooker
1. High voltage rectifier and converter circuit
Generally speaking, this kind of circuit filters out impurities in the power grid through capacitors and inductors, and then rectifies it into about 365,438+00 direct current, which is supplied to the coil disk and IGBT tube as the main components of normal working voltage: capacitors, inductors, varistors, fuse tubes and bridge stacks.
2. Low-voltage power supply voltage stabilizing circuit
This circuit outputs a DC voltage of about 300V from the pre-unit circuit, and then outputs it to the low-voltage power supply required by the induction cooker after the voltage is reduced and stabilized by the switching circuit. This is the origin of 18V and 5V. This circuit involves many things. If you are interested, you can learn about switching power supply. I will share this knowledge with you later.
3.LC oscillation inverter circuit
LC oscillation inverter circuit is the working circuit of induction cooker. Through the turn-on and turn-off of IGBT, the current oscillates between the coil disk and the high-frequency capacitor (0.2uF capacitor), forming eddy current heating at the bottom of the iron pot. Components mainly include IGBT, excitation coil and high-frequency capacitor.
4. Synchronous detection circuit
The synchronous detection circuit detects the synchronous signals from both ends of the parallel circuit of the coil disk and the high resonance capacitor, and controls the driving voltage of the G pole of IGBT after shaping and amplification, so that the leading edge of the G pole switching pulse voltage applied to IGBT is synchronized with the trailing edge of the C pole peak voltage. Vividly speaking, it is sampling, sending samples and comparing execution.
5. Oscillating sawtooth wave forming circuit
The main function of the oscillating sawtooth wave forming circuit is to form a certain sawtooth wave voltage according to the synchronous detection voltage and the driving control voltage generated by CPU to drive the subsequent circuits.
6.IGBT high voltage protection circuit
The popular saying is to protect IGBT circuit, and the elegant saying is: detect IGBT reverse peak pulse voltage to protect lGBT from damage.
7. Surge protection circuit
Surge protection circuit is when the 220v AC input voltage suddenly appears surge voltage, that is to say, sometimes the commercial power will come like waves. At this time, the surge protection circuit sends the detected voltage signal to the integrated circuit, and then the integrated circuit outputs a signal to turn off the IGBT, and the induction cooker stops working.
8. Pot temperature detection circuit
It protects the induction cooker from high temperature damage by changing the resistance of the thermistor in the center of the coil disk. There are two parts: overheating protection and dry burning protection.
9.lGBT temperature detection circuit
Like the pot temperature detection circuit, IGBT is also protected by the temperature change of thermistor. Generally, the IGBT thermistor is placed under the IGBT and can only be seen by disassembling the heat sink. There are also fan drive circuits, buzzer drive circuits, etc. Relatively speaking, these circuits are not so important and complicated, so we skipped them.
2. Selection skills of induction cooker
1, from the functional point of view, we not only require the induction cooker to provide a lot of heat when cooking food, but also it should have a variety of protective devices. Various protection devices of induction cooker include small object detection, overheating protection, over-voltage and under-voltage protection, air-burning stop heating protection and other functions. Before buying, we can know the specific protection function of the induction cooker through its manual, so as to better protect the safety of users.
2. The cooling fan plays a very important role in the induction cooker. The diagonal size of the cooling fan at the bottom of the induction cooker is larger, which means that its cooling performance will be better. The cooling fan of induction cooker mainly adopts magnetic levitation, hydraulic or nano-ceramic fan. If the induction cooker can be disassembled, you can press the fan blades by hand. If the blade pressure is 2mm, it means that its fan is a magnetic levitation fan. The cooling efficiency of the cooling fan in the induction cooker will affect the service life of the internal components of the induction cooker, and a good cooling fan will reduce the noise generated by the machine during use.
Well, having said that, you should have a certain understanding of the circuit structure of induction cooker and the selection skills of induction cooker. I didn't expect a small induction cooker to have so many complicated circuit structures. Do you think technology has changed our lives? Want to know more about the latest information about home improvement, please continue to pay attention.