为了保证柔性直流输电工程的可靠运行,在投入运行之前必须通过一系列试验来考察换流阀的安全可靠性,这就需要制定一套科学全面的型式试验方案来验证考核换流阀设计的正确性。针对模块化多电平换流阀(modular multilevel converter,M M C...为了保证柔性直流输电工程的可靠运行,在投入运行之前必须通过一系列试验来考察换流阀的安全可靠性,这就需要制定一套科学全面的型式试验方案来验证考核换流阀设计的正确性。针对模块化多电平换流阀(modular multilevel converter,M M C)的结构和工作原理,参考相关标准,以南澳多端柔性直流输电工程为例,研究提出了详细的M M C的型式试验方案,该方案能够较全面地验证基于MMC拓扑结构的换流阀及其相关电路设计的正确性。展开更多
The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS)...The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS) PWM push pull three level converter in which the voltage stress of switches is input voltage. With phase shifted modulation strategy, the leading switches can only realize zero voltage switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero voltage and zero current switching PWM push pull three level converters are proposed.展开更多
With the use of this novel average model for Single Stage Flyback PFC+Flyback DC/DC converter, voltage control mode, peak current control mode and average current control mode can be simulated easily by changing the m...With the use of this novel average model for Single Stage Flyback PFC+Flyback DC/DC converter, voltage control mode, peak current control mode and average current control mode can be simulated easily by changing the model's parameters. It can be used to do various analysis not only for small signal and static behavior but also for large signal and dynamic behavior of the converter. By using this average model the simulation speed can be improved by 2 orders of magnitude above that obtained by using the conventional switched model. It can be applied to optimize the trade\|off between high power factor, voltage stress, current stress and good output performance while designing this kind of single stage PFC converter. A 60W single stage power factor corrector was built to verify the proposed model. The modeling principle can be applied to other Single Stage PFC topologies.展开更多
In the first part, the concept of instrumental reason is defended. Although we live in the age of pluralism, in which a tendency prevails to put all types of rationality on the same plane, there is a rationality that ...In the first part, the concept of instrumental reason is defended. Although we live in the age of pluralism, in which a tendency prevails to put all types of rationality on the same plane, there is a rationality that has a unique position： the instrumental rationality. The article then examines Luk^ics＇s roots of this concept and its elaboration by Adomo and Horkheimer. The second part refers to the current transformation of instrumental reason that these authors could not register. Instrumental reason changes so that it can connect several seemingly incoherent elements： postmodern non-objectivity, social and ecological normativity, and reified imperatives of capitalism. This formation is here called over-instrumental instrumental reason. In conclusion, the article deals with the question of how its non-instrumental component to exempt from its instrumental ones.展开更多
文摘为了保证柔性直流输电工程的可靠运行,在投入运行之前必须通过一系列试验来考察换流阀的安全可靠性,这就需要制定一套科学全面的型式试验方案来验证考核换流阀设计的正确性。针对模块化多电平换流阀(modular multilevel converter,M M C)的结构和工作原理,参考相关标准,以南澳多端柔性直流输电工程为例,研究提出了详细的M M C的型式试验方案,该方案能够较全面地验证基于MMC拓扑结构的换流阀及其相关电路设计的正确性。
文摘The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS) PWM push pull three level converter in which the voltage stress of switches is input voltage. With phase shifted modulation strategy, the leading switches can only realize zero voltage switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero voltage and zero current switching PWM push pull three level converters are proposed.
文摘With the use of this novel average model for Single Stage Flyback PFC+Flyback DC/DC converter, voltage control mode, peak current control mode and average current control mode can be simulated easily by changing the model's parameters. It can be used to do various analysis not only for small signal and static behavior but also for large signal and dynamic behavior of the converter. By using this average model the simulation speed can be improved by 2 orders of magnitude above that obtained by using the conventional switched model. It can be applied to optimize the trade\|off between high power factor, voltage stress, current stress and good output performance while designing this kind of single stage PFC converter. A 60W single stage power factor corrector was built to verify the proposed model. The modeling principle can be applied to other Single Stage PFC topologies.
文摘In the first part, the concept of instrumental reason is defended. Although we live in the age of pluralism, in which a tendency prevails to put all types of rationality on the same plane, there is a rationality that has a unique position： the instrumental rationality. The article then examines Luk^ics＇s roots of this concept and its elaboration by Adomo and Horkheimer. The second part refers to the current transformation of instrumental reason that these authors could not register. Instrumental reason changes so that it can connect several seemingly incoherent elements： postmodern non-objectivity, social and ecological normativity, and reified imperatives of capitalism. This formation is here called over-instrumental instrumental reason. In conclusion, the article deals with the question of how its non-instrumental component to exempt from its instrumental ones.
