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

随着世界范围内能源需求的增加，随着对环境的关注，可替代能源要么集成到现有电网中，要么集成到使用交流和直流混合母线的微电网中，以确保更高的电力安全。这些能源的输出差异很大，包括一些运行限制，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的输出电压波形变化幅度和频率都不同；燃料电池产生的低电压DC(22-41V)变化范围很大，对负载变化的暂态响应很慢，而且对纹波电流非常敏感。*当不同的能源连接到DC母线时，需要一个双向DC/DC转换器来为电池或超级电容器充电，以及为DC母线供电。DC-AC逆变器需要用于公用设施接口以增强发电量或用于独立运行。因此，为了满足这些能源的限制，低成本、高效率的电力电子转换器是这类系统不可或缺的一部分。使用具有高效率、小体积、轻重量、减少EMI、低元件应力等优点的低损耗和高开关频率的软开关变流器是可能的。因此，本工作的主要目标是：(1)提出、分析和设计新型高频变压器隔离软开关单相和三相功率变流器拓扑结构(单向和双向DC/DC、用于实用接口的DC/AC和用于PMSG和线性发电机的具有高功率因数的AC/DC)；(2)开发用于直接AC/AC转换的软开关电子变压器；(3)用于高功率应用的交错操作；以及(4)研究使用INTUSOFT SPICE或PSIM仿真软件设计的转换器的性能，并构建原型实验转换器。*建议的转换器将减小体积和重量(由于高开关频率、低损耗和高频变压器隔离)，在满足严格的能源要求的同时降低成本。为风力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，其中一些将采用高频变压器隔离的单级功率变换。由于加拿大利用海浪和风能发电的潜力巨大，拟议中的变流器将在此类系统中发挥作用。这项提议预计将在电力电子领域培养3名博士、3名硕士和几名本科生，重点是替代能源系统的应用。他们将接受实验转换器的分析、设计、模拟和制造方面的培训。**

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.**