串联功率半导体瞬态均压技术研究

发布时间：2018-04-16 16:38

本文选题：串联功率半导体 + 瞬态电压平衡　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：在能源危机日益严重的今天,交流输电网络已经不能满足电力输送的要求,因此高压直流输电技术蓬勃发展。高压直流断路器作为直流输电的核心部件备受关注。高压直流断路器由串联半导体构成,在半导体开通关断过程中半导体之间容易出现电压不平衡。本课题研究串联功率半导体开关瞬态均压技术。本文分析了功率半导体的开关过程,串联功率半导体的瞬态可靠性,无源均压技术对串联功率半导体的瞬态均压的作用,针对串联半导体的控制所需的辅助电源进行了设计,为解决串联半导体的瞬态电压不平衡设计了有源控制方法,实现了可以保证串联功率半导体开关瞬态电压平衡的低压等效模型。为分析串联半导体开关瞬态可靠性,研究了功率半导体的微观等效模型,建立了串联MOSFET微观等效电路的转移状态矩阵,使用转移状态矩阵特征根判定的方法,对串联MOSFET的开关可靠性进行观测,并选取合适的门极电阻。以MOSFET 20N60为例进行了计算。同时分析串联半导体无源均压的原理,研究设计了无源均压电路参数设计方法与无源均压电路对系统的影响,实验验证了无源均压电路抑制瞬态过电压的效果。针对串联功率半导体门极供电需求,设计了一个具有多路输出能力,有隔离高电压能力的辅助电源,辅助源包括前级70 k Hz逆变器和后级5 V输出的稳压电路。为保证输出正弦波形,针对逆变器的滤波网络进行了分析,选择了两级Г型滤波网络,并进行推导计算。为了保证开关过程中的瞬态均压,分析了瞬态电压不平衡的原因。设计了开关状态高速采样电路,开关控制程序,使用状态机的方法,结合FPGA的高速特性,产生相对延迟的控制信号来消除误差,最终实现了串联开关管的瞬态均压,在实验平台上实现了1000 V耐压100 ns开通的串联半导体低压等效模型。实验结果表明,本课题所设计的均压策略可保证开关管电压瞬态平衡。
[Abstract]:With the increasingly serious energy crisis, the AC transmission network has been unable to meet the requirements of power transmission, so HVDC technology is booming.As the core components of HVDC transmission, HVDC circuit breakers have attracted much attention.High voltage DC circuit breaker is composed of series semiconductor.In this paper, the transient voltage sharing technology of series power semiconductor switch is studied.In this paper, the switching process of power semiconductors, the transient reliability of series power semiconductors and the effect of passive voltage sharing technology on the transient voltage equalization of series power semiconductors are analyzed. The auxiliary power supply for the control of series semiconductors is designed.In order to solve the transient voltage imbalance of series semiconductor, an active control method is designed, and a low-voltage equivalent model is implemented to guarantee the transient voltage balance of series power semiconductor switch.In order to analyze the transient reliability of series semiconductor switch, the microscopic equivalent model of power semiconductor is studied, and the transfer state matrix of series MOSFET microcosmic equivalent circuit is established. The method of determining the eigenvalue of the transfer state matrix is used.The switching reliability of series MOSFET is observed and the appropriate gate resistance is selected.Taking MOSFET 20N60 as an example, the calculation is carried out.At the same time, the principle of passive voltage sharing in series semiconductor is analyzed, the parameter design method of passive voltage sharing circuit and the influence of passive voltage sharing circuit on the system are studied, and the effect of passive voltage sharing circuit on suppressing transient overvoltage is verified by experiments.In order to meet the demand of series power semiconductor gate power supply, an auxiliary power supply with multiple output capacity and isolation high voltage capability is designed. The auxiliary source includes a 70 kHz inverter with a front stage and a stable circuit with a 5 V output from the rear stage.In order to guarantee the output sinusoidal shape, the filter network of inverter is analyzed, and the two-stage filter network is selected and calculated.In order to ensure the transient voltage balance in the switching process, the cause of the transient voltage imbalance is analyzed.The switching state high-speed sampling circuit, switching control program, using state machine method and combining the high speed characteristic of FPGA are designed to produce the relative delay control signal to eliminate the error. Finally, the transient voltage equalization of the series switch tube is realized.A low voltage equivalent model of 1000 V and 100ns open series semiconductor is realized on the experimental platform.The experimental results show that the voltage balancing strategy designed in this paper can guarantee the transient voltage balance of the switch tube.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46;TM561

【参考文献】