This paper presents an optimal operation method for embedded DC interconnections based on low-voltage AC/DC distribution areas(EDC-LVDA)under three-phase unbalanced compensation conditions.It can optimally determine t...This paper presents an optimal operation method for embedded DC interconnections based on low-voltage AC/DC distribution areas(EDC-LVDA)under three-phase unbalanced compensation conditions.It can optimally determine the transmission power of the DC and AC paths to simultaneously improve voltage quality and reduce losses.First,considering the embedded interconnected,unbalanced power structure of the distribution area,a power flow calculation method for EDC-LVDA that accounts for three-phase unbalanced compensation is introduced.This method accurately describes the power flow distribution characteristics under both AC and DC power allocation scenarios.Second,an optimization scheduling model for EDC-LVDA under three-phase unbalanced conditions is developed,incorporating network losses,voltage quality,DC link losses,and unbalance levels.The proposed model employs an improved particle swarm optimization(IPSO)two-layer algorithm to autonomously select different power allocation coefficients for the DC link and AC section under various operating conditions.This enables embedded economic optimization scheduling while maintaining compensation for unbalanced conditions.Finally,a case study based on the IEEE 13-node system for EDC-LVDA is conducted and tested.The results show that the proposed optimal operation method achieves a 100%voltage compliance rate and reduces network losses by 13.8%,while ensuring three-phase power balance compensation.This provides a practical solution for the modernization and upgrading of low-voltage power grids.展开更多
单级式双有源桥(dual active bridge,DAB)DC/AC变换器控制自由度多,变压器匝比、漏感、开关频率等参数相互耦合,导致变换器效率优化面临多重制约。该文分析变压器匝比、漏感与软开关范围、漏感电流有效值、漏感电流峰值之间的约束关系,...单级式双有源桥(dual active bridge,DAB)DC/AC变换器控制自由度多,变压器匝比、漏感、开关频率等参数相互耦合,导致变换器效率优化面临多重制约。该文分析变压器匝比、漏感与软开关范围、漏感电流有效值、漏感电流峰值之间的约束关系,提出直接表征DAB-DC/AC变换器效率的物理量:效率敏感因子。通过研究效率敏感因子对系统损耗的影响机理,实现变换器效率最优的硬件参数设计,为多参数耦合的单级式DAB-DC/AC变换器效率优化提供理论指导。最后通过一台450 W样机验证所提理论的正确性。展开更多
High-temperature,high-power converters have gained importance in industrial applications given their ability to operate in adverse environments,such as in petroleum exploration,multi-electric aircrafts,and electric ve...High-temperature,high-power converters have gained importance in industrial applications given their ability to operate in adverse environments,such as in petroleum exploration,multi-electric aircrafts,and electric vehicles.SiC metaloxide-semiconductor field-effect transistor(MOSFET),a new,wide bandgap,high-temperature device,is the key component of these converters.In this study,the static and dynamic characteristics of the SiC MOSFET,half-bridge module,are investigated at the junction temperature of 180℃.A simplified experimental method is then proposed pertaining to the power operation of the SiC module at 180℃.This method is based on the use of a thermal resistance test platform and is proven convenient for the study of heat dissipation characteristics.The high-temperature characteristics of the module are verified based on the conducted experiments.Accordingly,a 100 kW high-temperature converter is built,and the test results show that the SiC converter can operate at a junction temperature of 180℃in a stable manner in compliance with the requirements of high-temperature,high-power applications.展开更多
在两级式AC-DC变换器中,前级功率因数校正(power factor correction,PFC)固有的瞬时功率波动特性会造成母线电压存在二倍频纹波,影响后级CLLLC谐振变换器的输出电压质量。针对以上问题,该文提出了基于二阶广义积分(second order general...在两级式AC-DC变换器中,前级功率因数校正(power factor correction,PFC)固有的瞬时功率波动特性会造成母线电压存在二倍频纹波,影响后级CLLLC谐振变换器的输出电压质量。针对以上问题,该文提出了基于二阶广义积分(second order generalized integral,SOGI)的可变增益母线电压纹波前馈控制方法。采用SOGI提取母线电压纹波信息,基于品质因数Q与电压增益的关系和母线电压纹波对归一化频率的影响,解析了母线电压纹波对CLLLC谐振变换器输出电压的影响机理,得到Q值与前馈增益系数Ka的关系,采用仿真寻优加数据拟合的方法得到前馈可变增益系数曲线。仿真和实验结果表明,相比于无前馈控制,所提控制方法对CLLLC谐振变换器的输出电压纹波具有较好的抑制效果,输出电压纹波降低了72%,验证了所提算法的有效性。展开更多
为了解决传统的两级式光伏交流模块PV AC module存在的结构复杂、成本高、效率低等问题,提出了一种新型PV AC module。该AC module的前级为传统的Boost变换器,完成光伏组件的最大功率点跟踪和光伏接口电压的泵升;后级采用高增益集成式...为了解决传统的两级式光伏交流模块PV AC module存在的结构复杂、成本高、效率低等问题,提出了一种新型PV AC module。该AC module的前级为传统的Boost变换器,完成光伏组件的最大功率点跟踪和光伏接口电压的泵升;后级采用高增益集成式逆变器,实现直流母线电压的泵升和并网发电功能。分析了PV AC module的系统结构,工作原理及控制策略,并通过一套250 W/40 kHz的样机仿真模型,验证了方案的可行性与理论分析的正确性。研究结果表明:该新型PV AC module具有结构简洁、控制简单、成本低、效率高等优点。展开更多
三相双有源桥双向AC/DC变换器具备高效双向变换和升降压运行的优势,适合应用于储能系统,但是该变换器在宽电压范围下运行时的参数设计与性能优化面临挑战。针对适用于该变换器在宽电压范围下实现零电压开关(zero voltage switching,ZVS...三相双有源桥双向AC/DC变换器具备高效双向变换和升降压运行的优势,适合应用于储能系统,但是该变换器在宽电压范围下运行时的参数设计与性能优化面临挑战。针对适用于该变换器在宽电压范围下实现零电压开关(zero voltage switching,ZVS)的混合调制策略,提出基于遗传算法的多目标参数优化方法;以开关管损耗和电感电流有效值作为优化目标,建立多目标优化模型,对电感值和变压器匝比进行求解;在实验室搭建一台1.5 kW的原理样机,实验结果表明,采用混合调制策略的变换器可在宽电压和宽功率范围下实现ZVS。此外,多目标优化参数设计方法能降低变换器的损耗,从而提升效率,为其性能提升提供了有效方案。展开更多
基金supported by the key technology project of China Southern Power Grid Corporation(GZKJXM20220041)partly by the National Key Research and Development Plan(2022YFE0205300).
文摘This paper presents an optimal operation method for embedded DC interconnections based on low-voltage AC/DC distribution areas(EDC-LVDA)under three-phase unbalanced compensation conditions.It can optimally determine the transmission power of the DC and AC paths to simultaneously improve voltage quality and reduce losses.First,considering the embedded interconnected,unbalanced power structure of the distribution area,a power flow calculation method for EDC-LVDA that accounts for three-phase unbalanced compensation is introduced.This method accurately describes the power flow distribution characteristics under both AC and DC power allocation scenarios.Second,an optimization scheduling model for EDC-LVDA under three-phase unbalanced conditions is developed,incorporating network losses,voltage quality,DC link losses,and unbalance levels.The proposed model employs an improved particle swarm optimization(IPSO)two-layer algorithm to autonomously select different power allocation coefficients for the DC link and AC section under various operating conditions.This enables embedded economic optimization scheduling while maintaining compensation for unbalanced conditions.Finally,a case study based on the IEEE 13-node system for EDC-LVDA is conducted and tested.The results show that the proposed optimal operation method achieves a 100%voltage compliance rate and reduces network losses by 13.8%,while ensuring three-phase power balance compensation.This provides a practical solution for the modernization and upgrading of low-voltage power grids.
文摘单级式双有源桥(dual active bridge,DAB)DC/AC变换器控制自由度多,变压器匝比、漏感、开关频率等参数相互耦合,导致变换器效率优化面临多重制约。该文分析变压器匝比、漏感与软开关范围、漏感电流有效值、漏感电流峰值之间的约束关系,提出直接表征DAB-DC/AC变换器效率的物理量:效率敏感因子。通过研究效率敏感因子对系统损耗的影响机理,实现变换器效率最优的硬件参数设计,为多参数耦合的单级式DAB-DC/AC变换器效率优化提供理论指导。最后通过一台450 W样机验证所提理论的正确性。
基金supported by the National Key R&D Program of China (grant no. 2017YFB0903303)
文摘High-temperature,high-power converters have gained importance in industrial applications given their ability to operate in adverse environments,such as in petroleum exploration,multi-electric aircrafts,and electric vehicles.SiC metaloxide-semiconductor field-effect transistor(MOSFET),a new,wide bandgap,high-temperature device,is the key component of these converters.In this study,the static and dynamic characteristics of the SiC MOSFET,half-bridge module,are investigated at the junction temperature of 180℃.A simplified experimental method is then proposed pertaining to the power operation of the SiC module at 180℃.This method is based on the use of a thermal resistance test platform and is proven convenient for the study of heat dissipation characteristics.The high-temperature characteristics of the module are verified based on the conducted experiments.Accordingly,a 100 kW high-temperature converter is built,and the test results show that the SiC converter can operate at a junction temperature of 180℃in a stable manner in compliance with the requirements of high-temperature,high-power applications.
文摘为了解决传统的两级式光伏交流模块PV AC module存在的结构复杂、成本高、效率低等问题,提出了一种新型PV AC module。该AC module的前级为传统的Boost变换器,完成光伏组件的最大功率点跟踪和光伏接口电压的泵升;后级采用高增益集成式逆变器,实现直流母线电压的泵升和并网发电功能。分析了PV AC module的系统结构,工作原理及控制策略,并通过一套250 W/40 kHz的样机仿真模型,验证了方案的可行性与理论分析的正确性。研究结果表明:该新型PV AC module具有结构简洁、控制简单、成本低、效率高等优点。
文摘三相双有源桥双向AC/DC变换器具备高效双向变换和升降压运行的优势,适合应用于储能系统,但是该变换器在宽电压范围下运行时的参数设计与性能优化面临挑战。针对适用于该变换器在宽电压范围下实现零电压开关(zero voltage switching,ZVS)的混合调制策略,提出基于遗传算法的多目标参数优化方法;以开关管损耗和电感电流有效值作为优化目标,建立多目标优化模型,对电感值和变压器匝比进行求解;在实验室搭建一台1.5 kW的原理样机,实验结果表明,采用混合调制策略的变换器可在宽电压和宽功率范围下实现ZVS。此外,多目标优化参数设计方法能降低变换器的损耗,从而提升效率,为其性能提升提供了有效方案。
