The Study And Implementation Of Induction System For The Injection Molding Machine

Nearly four decades, with the rapid development of power electronics technology, the induction heating system with the principle of electromagnetic induction constantly change, small power, low-frequency induction heating system development to today's high-power, high frequency systems, and has heating efficiency, thermal pollution of small, fast, controllable and easy to implement intelligent, automated, etc, so the traditional heating methods in industry have been generally modified for the induction heating method.. Especially with the outline of the eleventh five-year plan proposed and the energy conservation and emission reduction strengthened, the plastics processing industry as one of China's pillar industry, its transformation of heating method plays an important role.Because induction heating system for injection molding machine in the market is with poor stability, low efficiency and high failure rates, the main content of this paper is to research the induction heating system for injection molding machine and realized. Based on the analysis of induction heating system trends in the industry and comparison of power components, light of actual demand of induction heating system for injection molding machine, this paper developed 6.3kW/20kHz induction system with IGBT.Analyzing and comparing the series resonant inverter structure and the parallel resonant inverter structure, the induction heating system is suitable for work in the induction quasi-resonant state with series resonant inverter structure. This paper gives the overall design of the injection molding machine induction heating system. In the control system hardware design, this paper introduces the core chips in the system, describes the concrete realization of the key signal acquisition and conditioning module, protection modules, interactive modules, isolation modules, and auxiliary power module, and focuses on analysis the operational principle of the lock Phase loop frequency tracking module which improved the traditional use of the MM74HC4046, realized the digital control of independent excitation to self-excited and the loss of lock during the operation, and ensured the system work in the induction quasi-resonant state.In the control system software design, this paper describes the programming ideas, achieves the every task function module in the system, completes the change of system task by using the task flags and focuses on analysis the PID control module.According to the system main circuit design, this paper analyzes the causes of the peak voltage and the peak current in the main circuit, gives the concrete solutions, study the structure and parameters of the selected IGBT power components, calculates the parameters of the key components detaily, eventually developes a prototype of 6.3kW/20kHz induction heating system for injection molding machine, tests the prototype and study the experimental results to verify feasibility, reliability and stability of the system.