通过器件串联技术可以用低电压等级的电力电子开关器件实现高电压等级的电力电子变换器，以解决目前开关器件电压等级受限的问题，在高压变换器领域有很大的应用前景。然而器件在开关瞬态过程中的不均压限制了串联技术在工业级产品中的应用，论文主要针对高压IGBT串联分析其开关瞬态动力学行为并研究其均压控制方法。研究单管IGBT开关瞬态动力学行为是研究串联IGBT瞬态特性的基础。本文结合IGBT器件内部元胞结构，建立了IGBT元胞等效电路，分析了电路中各等效元器件的数学描述，提出了精细栅极结构和基区变载流子寿命的高压IGBT机理模型。搭建了高压IGBT测试平台，验证了模型精度。通过分时间段对模型解耦降阶，研究了单管IGBT开关瞬态行为的解析描述。在高压IGBT单管模型的基础上，研究了适用于高压IGBT串联的机理模型。针对拖尾阶段的不均压现象，对单管模型中的BJT部分建模进行了改进，提出了考虑基区载流子二维分布的机理模型。搭建了高压IGBT双管串联测试平台，对模型进行了验证，重点验证了模型在描述拖尾阶段不均压方面的精度。在高压IGBT串联机理模型的基础上，分析了各类开关瞬态不均压行为以及不均压影响因素。在对高压IGBT串联开关瞬态行为分析的基础上，提出了高压IGBT串联主动均压控制方法，包括主电路侧均压电路、栅极侧有源箝位电路、反馈通路和前向控制通路四部分。分析了主电路侧均压电路和栅极有源箝位电路在不均压时对尖峰电压的抑制效果，设计了以有源箝位动作时间作为反馈信号的反馈通路以及通过对栅极时序进行调节实现均压的前向控制通路，针对每一部分电路分别给出了详细的电路参数设计方法。针对基于开关瞬态的主动均压控制其控制时间尺度小、控制阶段电磁干扰大等关键技术问题，提出了综合考虑硬件模拟电路和软件控制策略的电磁兼容设计方法，设计了满足精度要求的短时间尺度反馈信号采样电路和可靠稳定的极小计算周期下的控制算法。最后，分别搭建了高压IGBT双管串联两电平实验平台（直流母线电压等级5kV）、双管串联三电平实验平台（直流母线电压等级10kV）和四管串联两电平实验平台（直流母线电压等级10kV），详细设计了变换器系统参数，对高压IGBT串联主动均压控制方法进行了验证。
Using series-connected power semiconductor devices allows that a switching unit is able to operate at a voltage higher than rated voltage of a single device. It would have wide application in high voltage converter market in consideration of rate voltage limitation of power devices until now. Transient unbalance voltage sharing is a major constraint for the application of series-connected power devices. This paper focuses on transient characteristics analysis and balancing control for series-connected high voltage IGBTs (HV-IGBTs).As an important part, the single HV-IGBT model is studied at first by considering its cell structure and building equivalent circuit for the cell. A HV-IGBT model considering the detailed gate structure and excess carrier concentration on its lifetime is proposed in this paper with validation for its accuracy. The mathematical description for the switching transient characteristics of the single IGBT is obtained by decoupling the model.The model which can describe the switching transient characteristics of HV-IGBTs in series connection is studied based on the single HV-IGBT model. A model for series connected HV-IGBTs considering the two-dimension distribution for excess carriers in the base is proposed in order to accurately describe the voltage unbalance during tail period with validation for its accuracy. The voltage unbalance with its main factors is analyzed in detail using the model.An active voltage balancing control method for series-connected HV-IGBTs is proposed including snubber in main circuit, gate active clamping circuit, feedback circuit and control circuit. The effect of snubber and gate active clamping circuit on limiting the peak voltage is studied. The action time of gate active clamping circuit is used as the feedback signal and the voltage balance is achieved by regulating the gate control signals of series-connected HV-IGBTs. The parameter design methods for these four parts are given in detail, respectively.Considering the small time scale and high electromagnetic interference (EMI) for the active voltage balancing control, some key issues are studied specifically for the control. The electromagnetic compatibility (EMC) design method is proposed with improvement in its hardware circuit and control strategy design. The high speed feedback circuit is designed to satify the sampling accuracy. The stablility of the high speed control algorithm is studied.Three types of platforms are established to validate the active voltage balancing control including a two-level converter using two HV-IGBTs in series connection with 5kV DC-link voltage, a three level converter using two HV-IGBTs in series connection with 10kV DC-link voltage and a two level converter using four HV-IGBTs in series connection also with 10kV DC-link voltage.
