Soft-switched high-frequency power converters for energy systems

随着能源需求和环境问题的增加，替代能源（燃料电池、风能、光电和海洋）越来越受欢迎。这些能源的输出差异很大，包括一些操作限制。一些例子是：(1)燃料电池产生变化很大的低压直流电（例如，22至41 V），对负载变化的瞬态响应缓慢，并且在纹波电流下性能下降。(2)与风力发电机组配套使用的永磁同步发电机产生变电压、变频率的交流输出，需要功率因数（pf）校正的交流/直流变换器来获得稳压直流母线。对于所有这些源，需要一个额外的dc/ac转换器单独或实用程序接口，以增加发电量。此外，当不同的能源连接到直流母线时，需要一个双向dc- dc转换器来为电池充电以及为直流母线供电，用于为燃料电池产生氢气的电解槽需要一个dc/dc转换器。因此，所有这些能源都需要低成本，高效率的dc/dc， dc/ac和ac/dc电力电子变换器，同时满足能源所施加的约束。这是可能的使用软开关（包括谐振）转换器工作低损耗和高开关频率。这些变换器具有许多优点，例如，高效率，体积小，重量轻，减少EMI，元件应力低等。

With increased energy demand and environmental concerns, alternate energy sources (fuel cell, wind, photovoltaic and ocean) are becoming popular. The outputs of these energy sources vary widely including some operational limits. Some examples are: (1) Fuel cells generate widely varying low voltage dc (e.g., 22 to 41 V) having slow transient response for load changes and has degraded performance with ripple currents. (2) Permanent magnet synchronous generators used with wind turbines generate varying voltage and varying frequency ac output demanding power factor (pf) corrected ac/dc converters to get a regulated dc bus. For all these sources, an additional dc/ac converter is required for stand alone or utility interface to augment power generation. In addition, when different energy sources are connected to a dc bus, a bidirectional dc-to-dc converter is needed for battery charging as well as to supply the dc bus and an electrolyser used to generate hydrogen for fuel cells requires a dc/dc converter. Therefore, all these energy sources require low cost, highly efficient dc/dc, dc/ac and ac/dc power electronic converters while satisfying the constraints imposed by the energy sources. This is possible using soft-switching (including resonant) converters operating with low losses and high switching frequencies. These converters have a number of advantages, e.g., high efficiency, small size, light weight, reduced EMI, low component stresses, etc.