To realize effective utilization of renewable energy sources,a novel polymorphic topology with hybrid control strategy based LLC resonant converter was analyzed and designed in this paper.By combining the merits of a ...To realize effective utilization of renewable energy sources,a novel polymorphic topology with hybrid control strategy based LLC resonant converter was analyzed and designed in this paper.By combining the merits of a full bridge LLC resonant converter,three-level half bridge LLC resonant converter,and variable frequency control mode,the converter realizes an intelligent estimation of input voltage by automatically changing its internal cir-cuit topology.Under this control strategy,different input voltages determine different operation modes.This is achieved in full bridge LLC mode when the input voltage is low.If the input voltage rises to a certain level,it operates in three-level half bridge LLC mode.These switches are digital and entirely carried out by the DSP(Digi-tal Signal Processor),which means that an auxiliary circuit is unnecessary,where a simple strategy of software modification can be utilized.Experimental results of a 500W prototype with 100V~600V input voltage and full load efficiency of up to 92%are developed to verify feasibility and practicability.This type of converter is suitable for applications with an ultra-wide input voltage range,such as wind turbines,photovoltaic generators,bioenergy,and other renewable energy sources.展开更多
A Cascade H Bridge (CHB) is evaluated for both electric vehicle motor traction control and off-vehicle charging against the Power ElectronicsUK Automotive Challenge for cost and mass for the year 2035. By combining th...A Cascade H Bridge (CHB) is evaluated for both electric vehicle motor traction control and off-vehicle charging against the Power ElectronicsUK Automotive Challenge for cost and mass for the year 2035. By combining the power electronics with batteries using low-voltage MOSFET transistors in a series cascade arrangement the cost and mass targets could be met 12 years earlier (in 2023 and 20 times lighter if an application specific integrated circuit (ASIC) is used. A 200 kW peak reference car was used to evaluate cost and mass benefits using four different topologies of power electronics. Vehicle installation is shown to be simplified as only passive cooling is required removing the need for liquid cooling systems and the arrangement is inherently safe;no high voltages are present when the vehicle is stationary. The inherently higher efficiency of CHB increases vehicle range. The converter with integrated batteries can also behave as an integrated on-board battery charger delivering additional off-vehicle benefits by removing the need for costly external chargers.展开更多
Multi-level converters have been used extensively in modern industry which calls for energy conversion with high-power and high-or medium-voltage.Because of its modularity and scalability,the multi-level converter wit...Multi-level converters have been used extensively in modern industry which calls for energy conversion with high-power and high-or medium-voltage.Because of its modularity and scalability,the multi-level converter with modular structure can be extended to different voltage levels and has a variety of forms in practical applications.It has attracted much attention from academia in the past decade,however,as a result of the numerous vulnerable power electronics sub-modules,significant challenges remain with regards to reliability.After summarizing the current research status of modular multilevel cascade converters,the main issues of reliability are reviewed in the paper.Firstly,the failure cases are thoroughly surveyed and classified,and the main failure causes are analyzed.Secondly,the reliability evaluation methods are reviewed and applied to the modular multilevel cascade converters.Thirdly,some promising measures to improve the reliability are presented and discussed,including parameter selection,redundancy design,fault-tolerant control and so on.Then,a complete reliability-oriented design procedure for the modular multilevel cascade converters is proposed.Finally,the challenges and opportunities to improve the reliability are concluded.展开更多
文摘To realize effective utilization of renewable energy sources,a novel polymorphic topology with hybrid control strategy based LLC resonant converter was analyzed and designed in this paper.By combining the merits of a full bridge LLC resonant converter,three-level half bridge LLC resonant converter,and variable frequency control mode,the converter realizes an intelligent estimation of input voltage by automatically changing its internal cir-cuit topology.Under this control strategy,different input voltages determine different operation modes.This is achieved in full bridge LLC mode when the input voltage is low.If the input voltage rises to a certain level,it operates in three-level half bridge LLC mode.These switches are digital and entirely carried out by the DSP(Digi-tal Signal Processor),which means that an auxiliary circuit is unnecessary,where a simple strategy of software modification can be utilized.Experimental results of a 500W prototype with 100V~600V input voltage and full load efficiency of up to 92%are developed to verify feasibility and practicability.This type of converter is suitable for applications with an ultra-wide input voltage range,such as wind turbines,photovoltaic generators,bioenergy,and other renewable energy sources.
文摘A Cascade H Bridge (CHB) is evaluated for both electric vehicle motor traction control and off-vehicle charging against the Power ElectronicsUK Automotive Challenge for cost and mass for the year 2035. By combining the power electronics with batteries using low-voltage MOSFET transistors in a series cascade arrangement the cost and mass targets could be met 12 years earlier (in 2023 and 20 times lighter if an application specific integrated circuit (ASIC) is used. A 200 kW peak reference car was used to evaluate cost and mass benefits using four different topologies of power electronics. Vehicle installation is shown to be simplified as only passive cooling is required removing the need for liquid cooling systems and the arrangement is inherently safe;no high voltages are present when the vehicle is stationary. The inherently higher efficiency of CHB increases vehicle range. The converter with integrated batteries can also behave as an integrated on-board battery charger delivering additional off-vehicle benefits by removing the need for costly external chargers.
基金Supported by the key program of National Natural Science Foundation of China under Grant 51490683.
文摘Multi-level converters have been used extensively in modern industry which calls for energy conversion with high-power and high-or medium-voltage.Because of its modularity and scalability,the multi-level converter with modular structure can be extended to different voltage levels and has a variety of forms in practical applications.It has attracted much attention from academia in the past decade,however,as a result of the numerous vulnerable power electronics sub-modules,significant challenges remain with regards to reliability.After summarizing the current research status of modular multilevel cascade converters,the main issues of reliability are reviewed in the paper.Firstly,the failure cases are thoroughly surveyed and classified,and the main failure causes are analyzed.Secondly,the reliability evaluation methods are reviewed and applied to the modular multilevel cascade converters.Thirdly,some promising measures to improve the reliability are presented and discussed,including parameter selection,redundancy design,fault-tolerant control and so on.Then,a complete reliability-oriented design procedure for the modular multilevel cascade converters is proposed.Finally,the challenges and opportunities to improve the reliability are concluded.
