This paper deals with optimization of hard switching commutation mode for high-power, high-frequency consumer applications for selected power transistor. The experimental investigation of suitable settings is outgoing...This paper deals with optimization of hard switching commutation mode for high-power, high-frequency consumer applications for selected power transistor. The experimental investigation of suitable settings is outgoing from simulation analysis of hard switching for different transistor structures. For these purposes, the simulation models of power semiconductor switches with high level of validity have been used. After that, the experimental analysis for selected transistor was done with change of parameters that are influencing commutation process of transistor. Target of such kind of analysis was to reach as low switching losses as possible, achieving high power density and efficiency of power system, without utilization of improved switching techniques such as resonant switching. The results confirm that this task is realizable through use of progressive semiconductor devices such as SiC diodes and/or through latest families of MOSFET devices.展开更多
随着双馈风电和高压直流输电(high-voltage direct-current,HVDC)在电力系统中的比例越来越大,电网换相换流器型HVDC(line-commutated converter based HVDC,LCC-HVDC)与双馈风电场、弱电网互联时会存在交互稳定问题,且振荡频率会呈现...随着双馈风电和高压直流输电(high-voltage direct-current,HVDC)在电力系统中的比例越来越大,电网换相换流器型HVDC(line-commutated converter based HVDC,LCC-HVDC)与双馈风电场、弱电网互联时会存在交互稳定问题,且振荡频率会呈现频率耦合特征。针对LCC-HVDC整流站存在的频率耦合现象,采用3-D傅里叶变换建立阻抗模型,分析LCC产生频率耦合现象的机理,进行各个影响因素对LCC频率耦合程度的敏感性分析。最后,研究频率耦合特性对LCC整流站、双馈风场、弱电网互联系统稳定性分析的影响,并通过时域仿真验证所得结论。展开更多
受端分层特高压直流受端高低压阀组接入不同电压等级的交流电网,为了提高设备可用率和减少在交流系统故障引起的功率损失,提出了换相失败预测控制的联动机制减小换相失败发生的概率。基于交流系统基波负序电压幅值的阀组谐波保护,在某...受端分层特高压直流受端高低压阀组接入不同电压等级的交流电网,为了提高设备可用率和减少在交流系统故障引起的功率损失,提出了换相失败预测控制的联动机制减小换相失败发生的概率。基于交流系统基波负序电压幅值的阀组谐波保护,在某个交流系统发生不对称故障时能退出相应阀组,保证另一阀组能继续运行。三相对称故障时利用阀组欠压保护作为后备保护。并在此基础上提出了分级多层次的保护动作策略,达到提高设备的可用率和减少功率损失的目的。理论分析和实时数字仿真(real time digital simulator,RTDS)试验验证了文中所提策略的正确性和可行性。展开更多
文摘This paper deals with optimization of hard switching commutation mode for high-power, high-frequency consumer applications for selected power transistor. The experimental investigation of suitable settings is outgoing from simulation analysis of hard switching for different transistor structures. For these purposes, the simulation models of power semiconductor switches with high level of validity have been used. After that, the experimental analysis for selected transistor was done with change of parameters that are influencing commutation process of transistor. Target of such kind of analysis was to reach as low switching losses as possible, achieving high power density and efficiency of power system, without utilization of improved switching techniques such as resonant switching. The results confirm that this task is realizable through use of progressive semiconductor devices such as SiC diodes and/or through latest families of MOSFET devices.
文摘随着双馈风电和高压直流输电(high-voltage direct-current,HVDC)在电力系统中的比例越来越大,电网换相换流器型HVDC(line-commutated converter based HVDC,LCC-HVDC)与双馈风电场、弱电网互联时会存在交互稳定问题,且振荡频率会呈现频率耦合特征。针对LCC-HVDC整流站存在的频率耦合现象,采用3-D傅里叶变换建立阻抗模型,分析LCC产生频率耦合现象的机理,进行各个影响因素对LCC频率耦合程度的敏感性分析。最后,研究频率耦合特性对LCC整流站、双馈风场、弱电网互联系统稳定性分析的影响,并通过时域仿真验证所得结论。
文摘受端分层特高压直流受端高低压阀组接入不同电压等级的交流电网,为了提高设备可用率和减少在交流系统故障引起的功率损失,提出了换相失败预测控制的联动机制减小换相失败发生的概率。基于交流系统基波负序电压幅值的阀组谐波保护,在某个交流系统发生不对称故障时能退出相应阀组,保证另一阀组能继续运行。三相对称故障时利用阀组欠压保护作为后备保护。并在此基础上提出了分级多层次的保护动作策略,达到提高设备的可用率和减少功率损失的目的。理论分析和实时数字仿真(real time digital simulator,RTDS)试验验证了文中所提策略的正确性和可行性。
