In this work,an oscillating-body wave energy converter(OBWEC)with a hydraulic power take-off(PTO)system named“Dolphin 1”is designed,in which the hydraulic PTO system is equivalent to a transfer station and plays a c...In this work,an oscillating-body wave energy converter(OBWEC)with a hydraulic power take-off(PTO)system named“Dolphin 1”is designed,in which the hydraulic PTO system is equivalent to a transfer station and plays a crucial role in ensuring the stability of the electrical energy output and the efficiency of the overall system.A corresponding mathematical model for the hydraulic PTO system has been established,the factors that influence its performance have been studied,and an algorithm for solving the optimal working pressure has been derived in this paper.Moreover,a PID control method to enable the hydraulic PTO system to automatically achieve optimal performance under different wave conditions has been designed.The results indicate that,compared with single-chamber hydraulic cylinders,double-chamber hydraulic cylinders have a wider application range and greater performance;the accumulator can stabilize the output power of the hydraulic PTO system and slightly increase it;excessively large or small hydraulic motor displacement hinders system performance;and each wave condition corresponds to a unique optimal working pressure for the hydraulic PTO system.In addition,the relationship between the optimal working pressure P_(m)and the pressure P_(h)of the wave force acting on the piston satisfies P_(m)^(2)=∫_(t_(1))^(t_(2))P_(h)^(2)dt/(t_(2)-t_(1)).Furthermore,adjusting the hydraulic motor displacement automatically via a PID controller ensures that the actual working pressure of the hydraulic PTO system consistently reaches or approaches its theoretically optimal value under various wave conditions,which is a very effective control method for enhancing the performance of the hydraulic PTO system.展开更多
Herein,PtO-supported GdFeO_(3)(PtO/GdFeO_(3))composite photocatalysts were synthesized by a solutionbased technique.Extensive analysis using various analytical instruments has shown that PtO plays a crucial function i...Herein,PtO-supported GdFeO_(3)(PtO/GdFeO_(3))composite photocatalysts were synthesized by a solutionbased technique.Extensive analysis using various analytical instruments has shown that PtO plays a crucial function in augmenting the visible light absorption capacity of composites.Better photogenerated charge carrier transport was credited with this improvement,which led to a decrease in bandgap energy as low as 2.14 eV.The PtO/GdFeO_(3) nanocomposites showed remarkable photocatalytic activity when exposed to visible light,especially in the conversion of CO_(2) into CH_(3)OH.After 9 h of light,a noteworthy yield of 1550μmol·g^(−1) of methanol was produced,demonstrating maximum efficiency at a dose of 2.0 g·L^(−1) and a concentration of 5.0%PtO/GdFeO_(3).This yield indicates the effectiveness of the heterostructure,which outperformed pristine GdFeO_(3) by a factor of 7.85.This significant enhancement highlights the potential advantages of the modified structure in improving performance.Most significantly,the photocatalyst's durability maintained 98.0%of its initial efficacy throughout five cycles.The success of PtO/GdFeO_(3) is largely due to the synergistic light absorption capabilities and enhanced photocharge carrier separation that the integration of PtO produced.It highlights the conversion of CO_(2) into valuable chemicals under visible light exposure,as well as the promise of mixed oxide nanostructures in ecologically responsible material creation.展开更多
PTO(Power Take Off)系统是波浪能发电的核心单元,可将波浪能转化为电能,但由于波浪的周期时变性,传统控制策略实时最大功率跟踪技术捕获的电能较低,为了提高发电功率,需要为PTO系统引入高效实时的最大功率跟踪控制算法。针对传统的在线...PTO(Power Take Off)系统是波浪能发电的核心单元,可将波浪能转化为电能,但由于波浪的周期时变性,传统控制策略实时最大功率跟踪技术捕获的电能较低,为了提高发电功率,需要为PTO系统引入高效实时的最大功率跟踪控制算法。针对传统的在线MPPT(Max Power Point Tracking)算法应用于波浪能领域存在的耗时长,准确性低等问题,提出了一种基于离线查表法的MPPT算法。该算法结合实际工况,以发电机的输入转速为观测变量,建立了每个转速与最大功率点的工作状态映射关系一维图表,利用TMS320F280049芯片进行查表运算处理,运算频率高,可达50 kHz。为验证查表MPPT算法的可行性,进行了模拟波浪能发电的干实验,并对比了离线查表MPPT算法与在线扰动观察MPPT算法的功率输出。结果表明,相对于常用的扰动观察MPPT,查表法MPPT具有快速,高效,准确的响应特性,且输出电功率可提高50%以上。展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52071094 and 51979065).
文摘In this work,an oscillating-body wave energy converter(OBWEC)with a hydraulic power take-off(PTO)system named“Dolphin 1”is designed,in which the hydraulic PTO system is equivalent to a transfer station and plays a crucial role in ensuring the stability of the electrical energy output and the efficiency of the overall system.A corresponding mathematical model for the hydraulic PTO system has been established,the factors that influence its performance have been studied,and an algorithm for solving the optimal working pressure has been derived in this paper.Moreover,a PID control method to enable the hydraulic PTO system to automatically achieve optimal performance under different wave conditions has been designed.The results indicate that,compared with single-chamber hydraulic cylinders,double-chamber hydraulic cylinders have a wider application range and greater performance;the accumulator can stabilize the output power of the hydraulic PTO system and slightly increase it;excessively large or small hydraulic motor displacement hinders system performance;and each wave condition corresponds to a unique optimal working pressure for the hydraulic PTO system.In addition,the relationship between the optimal working pressure P_(m)and the pressure P_(h)of the wave force acting on the piston satisfies P_(m)^(2)=∫_(t_(1))^(t_(2))P_(h)^(2)dt/(t_(2)-t_(1)).Furthermore,adjusting the hydraulic motor displacement automatically via a PID controller ensures that the actual working pressure of the hydraulic PTO system consistently reaches or approaches its theoretically optimal value under various wave conditions,which is a very effective control method for enhancing the performance of the hydraulic PTO system.
基金support from National Natural Science Foundation of China(21771047)Natural Science Foundation of Heilongjiang Province,China(YQ2020E029)Open Project of State Key Laboratory of Inorganic Synthesis&Preparative Chemistry,Jilin University(2023-17).
文摘Herein,PtO-supported GdFeO_(3)(PtO/GdFeO_(3))composite photocatalysts were synthesized by a solutionbased technique.Extensive analysis using various analytical instruments has shown that PtO plays a crucial function in augmenting the visible light absorption capacity of composites.Better photogenerated charge carrier transport was credited with this improvement,which led to a decrease in bandgap energy as low as 2.14 eV.The PtO/GdFeO_(3) nanocomposites showed remarkable photocatalytic activity when exposed to visible light,especially in the conversion of CO_(2) into CH_(3)OH.After 9 h of light,a noteworthy yield of 1550μmol·g^(−1) of methanol was produced,demonstrating maximum efficiency at a dose of 2.0 g·L^(−1) and a concentration of 5.0%PtO/GdFeO_(3).This yield indicates the effectiveness of the heterostructure,which outperformed pristine GdFeO_(3) by a factor of 7.85.This significant enhancement highlights the potential advantages of the modified structure in improving performance.Most significantly,the photocatalyst's durability maintained 98.0%of its initial efficacy throughout five cycles.The success of PtO/GdFeO_(3) is largely due to the synergistic light absorption capabilities and enhanced photocharge carrier separation that the integration of PtO produced.It highlights the conversion of CO_(2) into valuable chemicals under visible light exposure,as well as the promise of mixed oxide nanostructures in ecologically responsible material creation.
文摘PTO(Power Take Off)系统是波浪能发电的核心单元,可将波浪能转化为电能,但由于波浪的周期时变性,传统控制策略实时最大功率跟踪技术捕获的电能较低,为了提高发电功率,需要为PTO系统引入高效实时的最大功率跟踪控制算法。针对传统的在线MPPT(Max Power Point Tracking)算法应用于波浪能领域存在的耗时长,准确性低等问题,提出了一种基于离线查表法的MPPT算法。该算法结合实际工况,以发电机的输入转速为观测变量,建立了每个转速与最大功率点的工作状态映射关系一维图表,利用TMS320F280049芯片进行查表运算处理,运算频率高,可达50 kHz。为验证查表MPPT算法的可行性,进行了模拟波浪能发电的干实验,并对比了离线查表MPPT算法与在线扰动观察MPPT算法的功率输出。结果表明,相对于常用的扰动观察MPPT,查表法MPPT具有快速,高效,准确的响应特性,且输出电功率可提高50%以上。
