Research Of Induction Heating Power Supply Based On Tms320F2812

In the view of the adverse situation that traditional induction heating power supply often uses hard-switching technology and analog control circuit, it is inevitable to have the shortcomings of low control precision, complex circuit, inefficiency and easy to aging, the capacitive phase-shifting PWM power modulation of induction heating power supply and its hardware and software of control system are studied intensively. After analysing the inverter working process in the resonant, inductive and capacitive load states, this paper selects insulated gate bipolar transistors (IGBT) as inverter switching devices, and using capacitive phase-shifting PWM to control the output power instantly based on TMS320F2812, this method focuses on soft-switching technology, frequency tracking technology and digital PID control technology, MATLAB simulation results show that the method is able to achieve smooth output of current and voltage and stable continuous adjustment of output power.The main contents of the paper are as follows:1. The basic structure and components of the power supply are analysed, the inverter working process in the resonant, inductive and capacitive load states are discussed in detail, by comparing the turn-on and turn-off condition of switching devices IGBT in the three states, the capacitive phase-shifting PWM power modulation is selected to control the inverter, thus achieving soft switching and stable real-time control of the output power.2. The various devices parameters of main circuit are selected according to actual design requirements, SIMULINK is used to simulate the inverter output current and voltage waveforms with phase shifting angle change under capacitive phase-shifting PWM control method, and simulation results show that the control method not only has wide adjustment range of phase shifting angle, but also achieves stable continuous adjustment of output power.3. The internal function modules and peripheral functions of the selected control chip TMS320F2812are introduced, the frequency, current and voltage detection circuit of load are designed respectively, M57962AL is chosen as integrated drive circuit of IGBT, and its internal structure diagram and peripheral application circuit are analysed.4. The software of power supply control system is designed, the main program flow chart of control system is listed, after comparing the advantages and disadvantages of software implementation with hardware implementation of digital phase-locked loop(DPLL), designing the DPLL software flow chart. Incremental PID control algorithm is used, PID control program flow chart is designed to adjust closed-loop control of the output power.