随着环保经济、绿色经济的发展，工业化道路也逐渐向更加节能、高效、环保的方向发展，与之相对应也推动了感应加热技术的发展。虽然国内的超音频感应加热技术发展迅速，但是在数字化、电路结构、容量等方面仍需要改进。因此本文以现场可编程门阵列（FPGA）为主控制芯片对超音频感应加热电源的数字化控制进行了研究。

首先，本文以超音频感应加热电源作为研究对象，对串联和并联谐振电路进行分析和对比，选择串联谐振电路作为负载的谐振电路，主电路采用三相不可控整流和单相全桥逆变电路拓扑结构。分析和对比现有不同调功方式的优劣，选取逆变侧脉冲移相调功方式，并且详细分析了在容性状态下脉冲移相调功方式的工作状态。针对串联谐振感应加热电源的频繁启动和负载谐振电路等效负载的突变问题，选用频率内环和功率外环相结合的双闭环控制策略。为克服传统PI调节算法的缺点，采用变参数和积分分离型的PI调节算法，提高了系统的快速性。

其次，对超音频感应加热电源系统的各项指标进行分析和计算，同时运用Matlab/Simulink软件对电源系统进行了建模，对锁相环模块和移相调功模块进行了仿真分析。与数字式PI分离调节算法比较，变参数和积分分离型的PI调节算法减小了超调量，改善了动态响应，提高了稳定性。仿真结果验证了控制策略的可行性。

最后，完成了FPGA外围、驱动、采样和保护等电路的设计。在实验室搭建了实验硬件平台，编写了基于Quartus II的软件程序，获得了各种输出波形。实验结果表明，全数字锁相环能快速跟踪负载频率的变化，功率连续可调，过流过压故障保护准确。进一步论证了本文控制方案的正确性和可行性。

With the development of environmental protection economy and green economy, the industrialization road has gradually developed towards the directions of energy conservation, high efficiency and environmental protection, which also has also promoted the development of induction heating technology. Although the domestic super audio induction heating technology has developed rapidly, it still needs to be improved in terms of digitization, circuit structure, and capacity. Therefore, in this paper, a field programmable gate array (FPGA) is used as the main control chip to research the digital control of the super audio induction heating power supply.

First of all, takes the super audio induction heating power supply as the research object, analyzes and compares the series-parallel load resonance circuit, selects the series resonance circuit as the research object, and the main circuit adopts a three-phase uncontrolled rectification and a single-phase full-bridge inverter topology. Analyze and compare the advantages and disadvantages of different power modulation methods on the DC side and the inverter side. Pulse phase shift power modulation on the inverter side is adopted. The working state of the pulse phase shift power modulation method in the capacitive state is analyzed in detail. To cope with the frequent start of series resonance induction heating power and the sudden change of the equivalent load of the load resonance circuit, the combination of closed loop control strategy with a frequency inner loop and a power outer loop was selected. In order to overcome the shortcomings of the traditional PI adjustment algorithm, a variable parameter and integral separation type PI adjustment algorithm is used to improve the system's rapidity.

With calculating and analyzing the various indicators of the super audio induction heating power system, the phase-locked loop module and the phase shifting modulator block are stimulated by using Matlab / Simulink software analysis. When compared with the Digital PI separation adjustment algorithm, the variable parameter and integral separation type PI adjustment algorithm reduces the overshoot, improves the dynamic response, and enhance the stability. As the result, Simulation results verify the feasibility of the control strategy.

Finally, completes the design of FPGA peripheral, driving, sampling and protection circuits. Using an experimental hardware in the laboratory, the software program based on Quartus II was written, and various output waveforms were obtained. The experimental results show that the all-digital phase-locked-loop can quickly track the change of load frequency; the power is continuously adjustable; and the overcurrent and overvoltage fault protection is accurate. The result further demonstrates the correctness and feasibility of the control scheme in this paper.