This paper presents an analysis of the effect of parasitic resistances on the performance of DC-DC Single Ended Pri- mary Inductor Converter (SEPIC) in photovoltaic maximum power point tracking (MPPT) applications. Th...This paper presents an analysis of the effect of parasitic resistances on the performance of DC-DC Single Ended Pri- mary Inductor Converter (SEPIC) in photovoltaic maximum power point tracking (MPPT) applications. The energy storage elements incorporated in the SEPIC converter possess parasitic resistances. Although ideal components significantly simplifies model development, but neglecting the parasitic effects in models may sometimes lead to failure in predicting first scale stability and actual performance. Therefore, the effects of parasitics have been taken into consideration for improving the model accuracy, stability, robustness and dynamic performance analysis of the converter. Detail mathematical model of SEPIC converter including inductive parasitic has been developed. The performance of the converter in tracking MPP at different irradiance levels has been analyzed for variation in parasitic resistance. The converter efficiency has been found above 83% for insolation level of 600 W/m2 when the parasitic resistance in the energy storage element has been ignored. However, as the parasitic resistance of both of the inductor has increased to 1 ohm, a fraction of the power managed by the converter has dissipated;as a result the efficiency of the converter has reduced to 78% for the same insolation profile. Although the increasing value of the parasitic has assisted the converter to converge quickly to reach the maximum power point. Furthermore it has also been observed that the peak to peak load current ripple is reduced. The obtained simulation results have validated the competent of the MPPT converter model.展开更多
目的:探讨血浆脂蛋白(a)[Lp(a)]与急性冠脉综合征(ACS)的关系及其评估ACS药物洗脱支架植入术患者预后的价值。方法:测定364例ACS患者、114例稳定型心绞痛(SAP)患者以及115例正常对照者的血Lp(a)水平;对ACS行药物洗脱支架植入术的患者随...目的:探讨血浆脂蛋白(a)[Lp(a)]与急性冠脉综合征(ACS)的关系及其评估ACS药物洗脱支架植入术患者预后的价值。方法:测定364例ACS患者、114例稳定型心绞痛(SAP)患者以及115例正常对照者的血Lp(a)水平;对ACS行药物洗脱支架植入术的患者随访6个月左右,根据Lp(a)的水平分为两组(A组≥300mg·L^(-1),B组<300mg·L^(-1)).随访有无心脏终点事件、支架内再狭窄及冠脉病变新进展。结果:ACS组Lp(a)浓度显著高于对照组及SAP组(中位数151.2/56.P<(0.001;151.2/70.4.P<0.001);A组心脏终点事件及冠脉病变新进展发生率显著高于B组(28.7% vs 8.8%,P<0.001;25.0% vs 10.1%,P=0.20),但是支架内再狭窄发生率在两组间无显著差异(15.9% vs 10.1%,P=0.322)。结论:Lp(a)与ACS的关系密切,而且是支架植入术后心脏终点事件及冠脉病变新进展的独立危险因素.但其与支架内再狭窄无显著关系。展开更多
文摘This paper presents an analysis of the effect of parasitic resistances on the performance of DC-DC Single Ended Pri- mary Inductor Converter (SEPIC) in photovoltaic maximum power point tracking (MPPT) applications. The energy storage elements incorporated in the SEPIC converter possess parasitic resistances. Although ideal components significantly simplifies model development, but neglecting the parasitic effects in models may sometimes lead to failure in predicting first scale stability and actual performance. Therefore, the effects of parasitics have been taken into consideration for improving the model accuracy, stability, robustness and dynamic performance analysis of the converter. Detail mathematical model of SEPIC converter including inductive parasitic has been developed. The performance of the converter in tracking MPP at different irradiance levels has been analyzed for variation in parasitic resistance. The converter efficiency has been found above 83% for insolation level of 600 W/m2 when the parasitic resistance in the energy storage element has been ignored. However, as the parasitic resistance of both of the inductor has increased to 1 ohm, a fraction of the power managed by the converter has dissipated;as a result the efficiency of the converter has reduced to 78% for the same insolation profile. Although the increasing value of the parasitic has assisted the converter to converge quickly to reach the maximum power point. Furthermore it has also been observed that the peak to peak load current ripple is reduced. The obtained simulation results have validated the competent of the MPPT converter model.
文摘目的:探讨血浆脂蛋白(a)[Lp(a)]与急性冠脉综合征(ACS)的关系及其评估ACS药物洗脱支架植入术患者预后的价值。方法:测定364例ACS患者、114例稳定型心绞痛(SAP)患者以及115例正常对照者的血Lp(a)水平;对ACS行药物洗脱支架植入术的患者随访6个月左右,根据Lp(a)的水平分为两组(A组≥300mg·L^(-1),B组<300mg·L^(-1)).随访有无心脏终点事件、支架内再狭窄及冠脉病变新进展。结果:ACS组Lp(a)浓度显著高于对照组及SAP组(中位数151.2/56.P<(0.001;151.2/70.4.P<0.001);A组心脏终点事件及冠脉病变新进展发生率显著高于B组(28.7% vs 8.8%,P<0.001;25.0% vs 10.1%,P=0.20),但是支架内再狭窄发生率在两组间无显著差异(15.9% vs 10.1%,P=0.322)。结论:Lp(a)与ACS的关系密切,而且是支架植入术后心脏终点事件及冠脉病变新进展的独立危险因素.但其与支架内再狭窄无显著关系。
