Design And Key Technology Of Medium Frequency Induction Heater

In view of the cold winter in northern China,heating is indispensable in every household.Because the traditional boiler heating method is mainly coal-fired,environmental pollution is serious.With the gradual increase of domestic wind power and photovoltaic power,the problem of abandoning wind and light is serious,and clean energy cannot be absorbed in time and wasted.Therefore,induction heating technology is widely used in water heating due to its high heating temperature,fast rate,high electro-thermal conversion efficiency,the use of clean energy,low environmental pollution,and automatic control.It can absorb clean energy such as photovoltaic and wind power for heating and energy storage,and has huge application prospects.This article analyzes the electromagnetic induction principle,skin effect and heat conduction based on the intermediate frequency induction heater.Various types of topological analysis of the main circuit in the induction heating power supply are carried out.The topology structure used in this design is determined by comparing its advantages and disadvantages.The transformer model is used to analyze its load equivalent,and the working process of the load resonant circuit in each state is explained.When the load is working in a weak inductive state,the load working state is optimal,and zero voltage turn-on can be achieved.There is no loss in natural commutation,and it is not easy to cause a through fault in the bridge.Then the design calculation and device selection of the main circuit and load parameters of the induction heater are carried out,and the IGBT is selected as the power switch of the inverter circuit.In view of the problem of loss and heating when power devices work,the thermal resistance equivalent circuit method is used to analyze and calculate the temperature of each point,and then the maximum thermal resistance value allowed by the heat sink is obtained,and a heat dissipation system is designed for the heating controller.The hardware is designed for the control circuit of induction heating power supply,and the single-chip STM32F103 is selected as the main control chip.The design includes the main control circuit and its basic peripheral circuits,PWM output circuit,IGBT drive and protection circuit,digital phase-locked loop circuit,temperature and water level sampling circuit,auxiliary power supply circuit,485 communication circuit,and detailed analysis of its circuitprinciple and main components used.For the main circuit and control circuit of induction heating power supply,according to the design parameters,a simulation model was built on the Multisim platform,and the simulation results obtained verified the rationality of the main circuit parameter design and the achievability of the phase-locked circuit.Then use Magnet software to simulate the electromagnetic field of the heater body,set the excitation to the output waveform of the heating power inverter circuit,and obtain the electromagnetic field and eddy current distribution rules,and select the best load structure parameters and the best core material through simulation verification.Finally,an experimental platform was built based on parameter design.After debugging and operation,voltage and current waveform analysis,temperature sampling analysis and efficiency check calculation were obtained,which verified the rationality and feasibility of parameter design.