摘要
对两级式光伏发电方案中DC/DC变换器进行了研究和设计。在变换器中同时采用了FB-PS-PWMZVS软开关技术和稳定性好、可靠性高的改进型CVT控制策略,并对FB-PS-PWMZVS技术存在的滞后桥臂实现软开关较为困难、副边整流尖峰干扰和CVT控制策略的温度影响等问题进行了分析。通过采用可饱和电感和增加辅助谐振网络解决了滞后桥臂实现软开关较为困难的问题;通过选用超快恢复二极管、在二极管回路中串入小电感、在变压器副边接入RC吸收网络等措施有效克服了副边整流尖峰;通过增加一块相同特性的较小光伏电池,实时检测其开路电压并按固定系数确定光伏最大工作点电压给定值,解决了传统CVT受温度影响大的问题。变换器实验效率达91.5%,优于不采取软开关技术的其他MPPT方案。
The DC/DC converter in a two-stage PV generation system is studied and designed.Both soft-switching technique of FB-PS-PWM ZVS and modified CVT control strategy with good stability and reliability are adopted in the converter.Analysis is performed on problems of implementing soft-switching in lagging leg,suppressing the interference of voltage spikes and resolving temperature effect on the performance of ordinary CVT.The problem which is difficult to implement soft-switching in lagging leg is resolved by adopting saturable inductance and auxiliary resonant networks.Voltage spikes of secondary polarity are suppressed effectively by using ultra-fast recovery diodes,adopting serially connected inductances in diodes loop,and employing RC absorbing networks in secondary polarity,etc.The problem which is the temperature significant effect on the performance of ordinary CVT is resolved by introducing a little PV cell and presetting the voltage at maximum PV point according to proportion of open circuit voltage.The efficiency of the converter is up to 91.5%,which is superior to other MPPT schemes without ZVS technology.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2011年第6期71-75,79,共6页
Power System Protection and Control
基金
河南省科技攻关计划项目(082102240096)
河南省教育厅自然科学基础研究计划项目(2008B470004)
