研究了一种新颖的反激式并网逆变器,从电路拓扑、控制策略、稳态原理特性、关键电路参数设计等相关内容对此逆变器进行了研究分析,此并网逆变器是由具有多路串联同时选择功率开关的隔离反激直流变换器和极性反转逆变桥级联组合而成,采...研究了一种新颖的反激式并网逆变器,从电路拓扑、控制策略、稳态原理特性、关键电路参数设计等相关内容对此逆变器进行了研究分析,此并网逆变器是由具有多路串联同时选择功率开关的隔离反激直流变换器和极性反转逆变桥级联组合而成,采用输出电流瞬时值反馈最大功率输出SPWM控制策略。设计并研制了500 W 38 V DC/220V50HzAC的实验样机,其电路结构简洁、输入输出电气隔离、输出并网电流优质、变换效率高,在小功率多输入源联合供电场合具有重要应用价值。展开更多
A single-stage flyback driving integrated circuit （IC） for light-emitting diodes （LEDs） is proposed. With an average primary-side current estimation and negative feedback networks, the driver operates in the bound...A single-stage flyback driving integrated circuit （IC） for light-emitting diodes （LEDs） is proposed. With an average primary-side current estimation and negative feedback networks, the driver operates in the boundary conduction mode （BCM）, while the output current can be derived and regulated precisely. By means of a simple external resistor divider, a compensation voltage is produced on the ISEN pin during the turn-on period of the primary MOSFET to improve the line regulation performance. On the other hand, since the delay time between the time that the secondary diode current reaches zero and the turn-on time of the MOSFET can be automatically adjusted, the MOSFET can always turn on at the valley voltage even if the inductance of the primary winding varies with the output power, resulting in quasi-resonant switching for different primary inductances. The driving IC is fabricated in a Dongbu HiTek＇s 0.35μm bipolar-CMOS-DMOS process. An 18 W LED driver is finally built and tested. Results show that the driver has an average efficiency larger than 86%, a power factor larger than 0.97, and works under the universal input voltage （85-265 V） with the LED current variation within ±0.5%.展开更多
文摘研究了一种新颖的反激式并网逆变器,从电路拓扑、控制策略、稳态原理特性、关键电路参数设计等相关内容对此逆变器进行了研究分析,此并网逆变器是由具有多路串联同时选择功率开关的隔离反激直流变换器和极性反转逆变桥级联组合而成,采用输出电流瞬时值反馈最大功率输出SPWM控制策略。设计并研制了500 W 38 V DC/220V50HzAC的实验样机,其电路结构简洁、输入输出电气隔离、输出并网电流优质、变换效率高,在小功率多输入源联合供电场合具有重要应用价值。
文摘提出了一种新颖的强升压能力的单级三相电压型准Z源光伏(photovoltaic,PV)并网逆变器,并对这种逆变器的电路拓扑、改进的空间矢量脉宽调制(space vector pulse width modulation,SVPWM)控制策略和低频工作模式、高频开关过程、外特性等稳态原理特性进行了深入研究,获得了重要结论和电压传输比表达式。该电路拓扑是由大升压比准Z源阻抗网络、三相逆变桥和三相LCL滤波器构成,该改进的SVPWM控制策略为大升压比阻抗网络储能电容电压控制和光伏电池最大功率跟踪(maximum power point tracking,MPPT)外环并网电流内环控制。实验结果验证了采用改进SVPWM控制策略的准Z源逆变器的实际性能。所提出的准Z源逆变器为实现低输入电压或宽变化范围输入电压的新能源并网发电提供了一种有效方法。
文摘A single-stage flyback driving integrated circuit （IC） for light-emitting diodes （LEDs） is proposed. With an average primary-side current estimation and negative feedback networks, the driver operates in the boundary conduction mode （BCM）, while the output current can be derived and regulated precisely. By means of a simple external resistor divider, a compensation voltage is produced on the ISEN pin during the turn-on period of the primary MOSFET to improve the line regulation performance. On the other hand, since the delay time between the time that the secondary diode current reaches zero and the turn-on time of the MOSFET can be automatically adjusted, the MOSFET can always turn on at the valley voltage even if the inductance of the primary winding varies with the output power, resulting in quasi-resonant switching for different primary inductances. The driving IC is fabricated in a Dongbu HiTek＇s 0.35μm bipolar-CMOS-DMOS process. An 18 W LED driver is finally built and tested. Results show that the driver has an average efficiency larger than 86%, a power factor larger than 0.97, and works under the universal input voltage （85-265 V） with the LED current variation within ±0.5%.
