Soft-switched high-frequency power converters for alternative energy systems

由于环境问题，全球能源需求不断增加，替代能源要么集成到现有电网中，要么集成到利用混合交流和直流母线的微电网中，以确保提高电能安全性。这些能源的输出变化很大，包括一些操作限制，例如：与风力涡轮机一起使用的永磁同步发电机（PMSG）产生不同电压和频率的交流输出；用于海浪能量转换的线性同步发电机具有变化幅度和频率的波动功率，输出电压波形；燃料电池产生变化范围广泛的低压直流电（22 至 41 V），对负载变化具有缓慢的瞬态响应，同时对纹波电流非常敏感。***   *当不同的能源连接到直流母线时，需要双向直流/直流转换器为电池或超级电容器充电以及为直流母线供电。公用设施接口需要直流转交流逆变器以增强发电量或独立运行。因此，为了满足这些能源的限制，低成本、高效的电力电子转换器是此类系统不可或缺的一部分。使用低损耗和高开关频率工作的软开关转换器可以实现这一点，该转换器具有许多优点，例如，高效率、小尺寸、轻重量、降低 EMI、低元件应力等。***   *因此，这项工作的主要目标是：(1) 提出、分析和设计新型高频 (HF) 变压器隔离软开关单相和三相电源转换器拓扑（用于公用接口的单向和双向 DC/DC、DC/AC 和用于 PMSG 和线性发电机的高功率因数交流/直流）； (2)开发用于直接交流/交流转换的软开关电子变压器； (3) 高功率应用的交错操作； (4) 使用 INTUSOFT SPICE 或 PSIM 仿真软件研究设计转换器的性能，并构建原型实验转换器。***   *建议的转换器将减小尺寸和重量（由于高开关频率、低损耗和高频变压器隔离），从而降低成本，同时满足能源的严格要求。为风能和海浪发电机开发的AC/DC和AC/AC转换器将具有高功率因数、低谐波失真，其中一些将具有带有高频变压器隔离的单级功率转换。加拿大海浪和风能发电潜力巨大，所提出的转换器将在此类系统中发挥作用。该提案预计将在电力电子领域培养 3 名博士生、3 名硕士生和数名本科生，重点关注替代能源系统的应用。他们将接受分析、设计、模拟和实验转换器构建方面的培训。**

World-wide increased energy demand with environmental concerns, alternative energy sources either integrated to the existing power grid or in a micro-grid utilizing hybrid ac and dc buses are becoming popular to ensure increased electrical energy security. The outputs of these energy sources vary widely including some operational limits, e.g.: permanent magnet synchronous generators (PMSG) used with wind turbines generate ac output of varying voltage and frequency; linear synchronous generators used in sea wave energy conversion have fluctuating power with varying amplitude and frequency output voltage waveform; fuel cells generate wide varying low voltage dc (22 to 41 V) having slow transient response for load changes while they are very sensitive to ripple currents.***   *When different energy sources are connected to a dc bus a bidirectional dc/dc converter is needed for battery or ultracapacitors charging as well as to supply the dc bus. A dc to ac inverter is required for utility interface to augment power generation or for standalone operation. Therefore, to satisfy the constraints imposed by these energy sources, low cost, highly efficient power electronic converters are indispensable part of such systems. This is possible using soft-switching converters operating with low losses and high switching frequencies having a number of advantages, e.g., high efficiency, small size, light weight, reduced EMI, low component stresses, etc. ***   *Therefore, main objectives of this work are: (1) to propose, analyze and design new high-frequency (HF) transformer isolated soft-switching single-phase and 3-phase power converter topologies (unidirectional and bidirectional dc/dc, dc/ac for utility interface and ac/dc with high power factor for PMSG and linear generators); (2) to develop soft-switched electronic transformers for direct ac/ac conversion; (3) interleaved operation for high power applications; and (4) to study the performance of designed converters using INTUSOFT SPICE or PSIM simulation software and building prototype experimental converters.***   *Proposed converters will have reduced size and weight (due to high switching frequency, low losses and HF transformer isolation) reducing their cost while satisfying the stringent requirements of energy sources. Ac/dc and ac/ac converters developed for wind and sea-wave generators will have high power factor, low harmonic distortion, some of them will have single stage power conversion with HF transformer isolation. With huge potential for power generation from sea wave and wind energy in Canada, proposed converters will be useful in such systems. This proposal is expected to train 3 Ph.D., 3 Master and several undergraduate students in the area of power electronics with emphasis on application to alternative energy systems. They will be trained in analysis, design, simulation and building of experimental converters.**