串联型高频感应加热电源锁相控制技术研究

发布时间：2018-06-30 06:43

本文选题：感应加热 + 逆变器　；参考：《华北电力大学》2017年硕士论文

【摘要】：由于感应加热电源具有清洁、节约能源、工作效率高等优点,在工业领域有着重要而广泛的应用,适用于金属熔炼、熔焊、金属热处理等场合。针对感应加热电源工作过程中负载等效参数会发生变化,从而影响感应加热电源高效稳定工作的问题,本文对高频感应加热电源的锁相控制技术进行了分析和研究。1.详细分析比较了串联谐振逆变器与并联谐振逆变器的拓扑结构和工作特性,对比了两种逆变器各自的优缺点,选取串联谐振逆变器作为本课题中感应加热电源的逆变部分。2.详细分析了锁相环各部分的基本原理,通过建立锁相环的数学模型,分析了锁相控制过程中的延时补偿环节对锁相控制性能的影响。提出了一种感应加热过程中负载频率升高情况下提高锁相控制动态响应速度的方法,仿真验证了该控制方法能有效改善感应加热电源的锁相控制性能。3.分析了串联谐振逆变器的三种工作状态,得出小感性状态为串联谐振逆变器的合适工作状态。详细分析了感性状态下逆变器的换流过程,得出了串联谐振逆变器的最佳工作状态,并根据直流侧电压、工作频率、吸收电容等条件计算出了其对应的最优锁相角度,实验验证了理论分析的正确性。4.将模拟电路与可编程器件FPGA相结合,设计了数模混合的电压电流双反馈定角锁相控制策略。完成了基于集成锁相环74HC4046的锁相电路、动态延时电路的设计,采用FPGA控制芯片完成了触发脉冲死区时间的生成以及负载电压、电流反馈信号相位的比较。搭建了感应加热电源实验平台,对感应加热电源的主电路结构、功率开关器件的驱动电路以及过电流保护电路与失锁保护电路进行了设计。实验验证了所设计的电压电流双反馈的定角锁相控制策略是有效可行的。
[Abstract]:Induction heating power has many advantages, such as clean, energy saving and high working efficiency. It is widely used in industry, and is suitable for metal melting, welding, heat treatment and so on. Aiming at the problem that the equivalent parameters of the load will change during the operation of the induction heating power supply, which will affect the efficient and stable operation of the induction heating power supply, the phase-locked control technology of the high-frequency induction heating power supply is analyzed and studied in this paper. The topology and working characteristics of series resonant inverter and parallel resonant inverter are analyzed and compared in detail. The advantages and disadvantages of the two kinds of inverter are compared. The series resonant inverter is selected as the inverter of induction heating power supply in this subject. The basic principle of each part of PLL is analyzed in detail. By establishing the mathematical model of PLL, the effect of delay compensation in the process of PLL on the performance of PLL is analyzed. A method to improve the dynamic response speed of phase-locked power supply under the condition of increasing load frequency during induction heating is proposed. The simulation results show that the control method can effectively improve the phase-locked control performance of induction heating power supply. Three kinds of working states of series resonant inverter are analyzed, and it is concluded that the small inductive state is the appropriate working state of series resonant inverter. The commutation process of inverter in inductive state is analyzed in detail, the optimal working state of series resonant inverter is obtained, and the corresponding optimal phase-locked angle is calculated according to DC side voltage, working frequency, absorption capacitance and so on. The experimental results show that the theoretical analysis is correct. Combining analog circuit with FPGA, a digital analog hybrid voltage and current double feedback angle-locked control strategy is designed. The phase-locked circuit based on integrated phase-locked loop 74HC4046 and the design of dynamic delay circuit are completed. The dead-time generation of trigger pulse and the phase comparison of load voltage and current feedback signal are completed by using FPGA control chip. The main circuit structure of induction heating power supply, driving circuit of power switch device, overcurrent protection circuit and lost lock protection circuit are designed. The experimental results show that the designed voltage and current double feedback control strategy is effective and feasible.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

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