DE类大功率高频逆变器的研究与实现

发布时间：2018-09-03 18:50

【摘要】：本文以感应加热电源为对象,研究一种以DE类功率放大器为基础的全桥逆变软开关技术。DE类功率放大器的功率器件工作在软开关状态,可以在很高的工作频率下保持高效率,并且DE类功率放大器对功率器件的电压应力要求较低。传统DE类功率放大器的功率器件为MOSFET(场效应管),这是由于场效应管开关速度快、损耗小,工作频率可以达到兆赫兹。但是,场效应管的单管电流不大,不适合应用在大功率高频电源场合中。本文研究感应加热技术,逆变器的输出功率比较大,功率管选择容量比较大的IGBT作为逆变器的功率器件。因此,本文DE类软开关技术使用IGBT作为高频大功率开关管。DE类功率放大器是以半桥逆变拓扑结构为基础的,而DE类全桥逆变是以全桥逆变拓扑结构为基础的。在相同工作频率下,此种拓扑结构比DE类功率放大器输出功率扩大了2倍,提高了输出功率,对研究高频大功率逆变电源提供了广阔的前景。在感应加热电源的加热过程中,谐振网络中的等效负载随着加热环境的变化而变化,等效负载并不恒定。在逆变器谐振频率和并联电容容值固定情况下,DE类全桥逆变的零电压转换(ZVS)和零电压导数转换(ZDS)条件的实现方式是通过控制驱动信号的死区时间。根据DE类全桥逆变控制策略的特性选择适合此逆变器结构的调功方式为直流调功方式。比较两种直流调功方式的优缺点,本文选择直流斩波调功方式,并且直流斩波调功为Buck恒流源而非电压源。为了验证DE类全桥逆变软开关技术的可行性,制作了一台实验样机。实验样机包括前级Buck恒流源部分和后级DE类全桥逆变部分。Buck恒流源设计输出功率为20kW,开关频率30kHz,输出电流调节范围为5~50A;DE类全桥逆变设计输出功率为20kW,IGBT工作频率60kHz,驱动信号的占空比可调范围为0.25~0.5。通过观察逆变回路中正弦电流和IGBT两端的电压波形,并参照对DE类全桥逆变的理论分析,实验结果证明DE类软开关能实现提高IGBT的工作频率,并将开关损耗控制在合适的范围。
[Abstract]:In this paper, a kind of full-bridge inverter soft-switching technology based on DE power amplifier. DE power amplifier is studied, which works in soft switching state, and can keep high efficiency at high working frequency. Moreover, the voltage stress of DE type power amplifier is low. The power device of traditional DE type power amplifier is MOSFET (Field effect Transistor), which is due to the fast switching speed and low loss of FET, and the operation frequency can reach MHz. However, the single transistor current of FET is small, so it is not suitable for high-power high-frequency power supply. In this paper, the induction heating technology is studied. The output power of the inverter is relatively large, and the IGBT with large capacity is chosen as the power device of the inverter. Therefore, the DE soft switching technology uses IGBT as the high-frequency high-power switch .DE power amplifier is based on the half-bridge inverter topology, while the DE full-bridge inverter is based on the full-bridge inverter topology. At the same operating frequency, the output power of this topology is increased by 2 times than that of DE type power amplifier, which provides a broad prospect for the study of high frequency and high power inverter power supply. In the heating process of induction heating power supply, the equivalent load in the resonant network changes with the change of heating environment, and the equivalent load is not constant. Under the condition of fixed resonant frequency of inverter and capacitance of parallel connection, the conditions of zero-voltage conversion (ZVS) and zero-voltage derivative conversion (ZDS) are realized by controlling the dead-time of driving signal. According to the characteristics of DE full-bridge inverter control strategy, the power regulation mode suitable for this inverter structure is the DC power regulation mode. Comparing the merits and demerits of the two DC power regulation modes, this paper chooses the DC chopper power modulation mode, and the DC chopper power modulation mode is a Buck constant current source rather than a voltage source. In order to verify the feasibility of DE full bridge inverter soft switch technology, an experimental prototype was made. The experimental prototype includes the front-stage Buck constant-current source and the backstage full-bridge inverter of DE class. The designed output power of the Buck constant-current source is 20kW, the switching frequency is 30kHz, and the output current regulation range is 50.50ADE full-bridge inverter design output power is 20kWN IGBT working frequency 60kHz. The adjustable duty cycle range of the driving signal is 0.25U 0.5. By observing sinusoidal current and voltage waveforms at both ends of IGBT in inverter circuit and referring to the theoretical analysis of full-bridge inverter of DE class, the experimental results show that DE soft switch can improve the frequency of IGBT and control the switching loss in an appropriate range.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464

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