【作者】 熊一频；

【导师】 沈锦飞；

【作者基本信息】 江南大学 ， 控制理论与控制工程， 2009， 硕士

【摘要】 感应加热电源广泛应用于各行各业中,这些工艺大都需要高频大功率的电源。目前,高频阶段都是采用功率MOSFET器件。由于MOSFET在高频化下的电压、电流容量等级低,使得其输出功率容量提升受到限制。本课题研究了基于MOSFET的倍频式700kHz大功率感应加热电源逆变电路的拓扑结构,逆变桥两组MOSFET采用并联分时导通,在逆变器输出的两个周期内,每个MOSFET工作一个周期,其工作频率为350kHz。为了进一步提高输出功率,运用MOSFET并联技术增加电流容量,从而提高输出功率。功率调节方式采用分时控制和密度调节复合调功方式,即分时—密度复合控制。论文对倍频式电源的拓扑结构和工作原理做了详细的分析。该功率控制方法是以复杂可编程逻辑器件CPLD为核心,利用VHDL硬件语言软件编程及模块化搭建,并用Quartus仿真软件对其进行了仿真试验,验证了其准确性。同时,设计了基于DSP的电流闭环控制系统,设计了DSP的数字PI调节,给出了功率闭环的整体框图。为保证电源正常运行,并使逆变器始终工作在功率因数接近或等于1的准谐振或谐振状态,以实现逆变器开关器件的零电流或零电压开关,设计了以高速集成锁相环74HC4046为核心的频率跟踪电路,并分析了锁相环的基本原理及数学建模。最后,通过分析比较各种MOSFET驱动电路,选用专用MOSFET驱动芯片IXDD430来完成驱动电路的设计。同时设计了保护及死区时间、启动、补偿时间形成等辅助电路。设计的700kHz的倍频式感应加热电源实验样机,MOSFET工作频率为350kHz,逆变器工作频率为700kHz。控制核心采用Altera公司的EPM1270CPLD产生倍频式感应加热电源分时—密度复合控制的驱动脉冲,利用TI公司的TMS320F2812DSP控制芯片实现功率闭环调节及保护,简化了系统结构。实验结果表明,倍频电源能有效提高电源工作频率,使之满足更多应用场合的需要。更多还原

【Abstract】 Induction heating power supplies are widely used in all walks of life, these processes are the need for high-power high-frequency power. At present, it uses the MOSFETs as high-frequency phase-power devices. As the MOSFET with the low level voltage and current, the capacity to enhance its output power is limited. This paper researches on an 700kHz double-frequency induction heater based on MOSFET. The main circuit is parallelling MOSFET in each of the traditional MOSFET and time-sharing controling, that is, in the the two cycles of inverter output, each MOSFET works one cycle, the operating frequency is 350kHz. To further enhance the output power, the use of MOSFET technology in parallel to increase current capacity, thereby enhancing the output power. Power regulating method is a new time-sharing PDM power control method of multiple frequency inverter is presented in this paper, which is based on PDM and time-sharing. Then, it analysed the structure and working principle of multiple frequency inverter. The implementation of the power control method is based on complex programmable logic device CPLD as its core. The use of VHDL hardware language programming, module structure and Quartus II simulation verified its accuracy. Meanwhile, a closed-loop system of current and power was designed, and the overall closed-loop block diagram of the power is proposed. Finally, through analysis and comparison of various MOSFET driver circuit, a dedicated MOSFET driver IC IXDD430 is choosed to complete driver circuit design. At the same time, protection and the formation of deadtime , starttime and compensationtime circuit are introducted. Finally a 700kHz multiple frequency inverter is made. MOSFETs’operating frequency is 350kHz, the inverter’s operating frequency is 700kHz. Control core using Altera’s EPM1270CPLD produce the control drive pulse of time-sharing control of multiple frequency inverter, the use of TI’s TMS320F2812 DSP implement closed-loop power control, simplifying the system architecture. The experimental results show that multiple frequency inverter can effectively improve the power supply frequency, so as to meet the needs of more applications.更多还原