With the widespread application of power electronic equipment in the power grid,the harmonic problem of the power grid becomes more pronounced,reducing the efficiency of power production,transmission,and utilization,a...With the widespread application of power electronic equipment in the power grid,the harmonic problem of the power grid becomes more pronounced,reducing the efficiency of power production,transmission,and utilization,and interfering with the normal operation of the power grid.Based on the requirements of harmonic suppression and power system protection,a shunt active power filter(SAPF)is proposed as an effective harmonic suppression method.However,there are problems with impulse current and impulse voltage in the starting process of SAPF.Impulse current and impulse voltage cause the power grid and switchgear to bear greater current stress and voltage stress,which seriously affect the security and reliability of the power grid and may damage the switchgear.To effectively solve the problem of impulse current and impulse voltage,the starting process of SAPF is divided into the uncontrolled rectification stage and the transition stage.The mathematical model of the DC side of APF is established.The causes of impulse current and impulse voltage in the uncontrolled rectifier and transition phases are analyzed.By introducing voltage square,a new starting impulse suppression strategy of active power filter based on the slow rising curve is proposed,fundamentally solving the problems of impulse current and impulse voltage.Simulation results verify the effectiveness and feasibility of this method.展开更多
全桥L-LLC谐振变换器在启动时存在谐振电流冲击大的现象,通常采用降频方式限制电流尖峰,从特定的高频逐渐降低到谐振频率,而由于谐振变换器的复杂动态特性,很难确定关键参数。因此,基于状态平面分析,提出了适用于全桥L-LLC谐振变换器的...全桥L-LLC谐振变换器在启动时存在谐振电流冲击大的现象,通常采用降频方式限制电流尖峰,从特定的高频逐渐降低到谐振频率,而由于谐振变换器的复杂动态特性,很难确定关键参数。因此,基于状态平面分析,提出了适用于全桥L-LLC谐振变换器的软启动策略。通过设计限流带确定最佳启动频率以及合理的降频策略,分三阶段将谐振电流限制在限流带内完成软启动。为了验证所提出的软启动策略的可行性,通过MATLAB/Simulink仿真验证,仿真结果表明,所提出的软启动策略不仅有效降低谐振电流过冲,还明显提高了启动速度,并能够保持原边侧开关管的零电压开通(zero voltage switching,ZVS)以及副边侧整流二极管的零电流关断(zero current switching,ZCS)特性。展开更多
基金supported by the National Natural Science Foundation of China under Grant 61863023.
文摘With the widespread application of power electronic equipment in the power grid,the harmonic problem of the power grid becomes more pronounced,reducing the efficiency of power production,transmission,and utilization,and interfering with the normal operation of the power grid.Based on the requirements of harmonic suppression and power system protection,a shunt active power filter(SAPF)is proposed as an effective harmonic suppression method.However,there are problems with impulse current and impulse voltage in the starting process of SAPF.Impulse current and impulse voltage cause the power grid and switchgear to bear greater current stress and voltage stress,which seriously affect the security and reliability of the power grid and may damage the switchgear.To effectively solve the problem of impulse current and impulse voltage,the starting process of SAPF is divided into the uncontrolled rectification stage and the transition stage.The mathematical model of the DC side of APF is established.The causes of impulse current and impulse voltage in the uncontrolled rectifier and transition phases are analyzed.By introducing voltage square,a new starting impulse suppression strategy of active power filter based on the slow rising curve is proposed,fundamentally solving the problems of impulse current and impulse voltage.Simulation results verify the effectiveness and feasibility of this method.
文摘全桥L-LLC谐振变换器在启动时存在谐振电流冲击大的现象,通常采用降频方式限制电流尖峰,从特定的高频逐渐降低到谐振频率,而由于谐振变换器的复杂动态特性,很难确定关键参数。因此,基于状态平面分析,提出了适用于全桥L-LLC谐振变换器的软启动策略。通过设计限流带确定最佳启动频率以及合理的降频策略,分三阶段将谐振电流限制在限流带内完成软启动。为了验证所提出的软启动策略的可行性,通过MATLAB/Simulink仿真验证,仿真结果表明,所提出的软启动策略不仅有效降低谐振电流过冲,还明显提高了启动速度,并能够保持原边侧开关管的零电压开通(zero voltage switching,ZVS)以及副边侧整流二极管的零电流关断(zero current switching,ZCS)特性。
