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

在世界范围内，由于环境问题，能源需求增加，替代能源要么集成到现有电网，要么在利用混合交流和直流总线的微电网中，以确保增加的电力能源安全正变得流行。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功率随幅值和频率的变化而波动；燃料电池产生宽变化的低压直流电（22至41 V），对负载变化的瞬态响应缓慢，而对纹波电流非常敏感。*** *当不同的能量源连接到直流母线时，需要双向dc/dc转换器来为电池或超级电容器充电以及为直流母线供电。一个直流到交流的逆变器是需要的公用事业接口，以增加发电或独立操作。因此，为了满足这些能源的限制，低成本、高效率的电力电子变换器是这类系统不可缺少的一部分。这可以使用具有许多优点的低损耗和高开关频率的软开关转换器，例如，高效率，小尺寸，重量轻，减少EMI，低元件应力等。因此，这项工作的主要目标是：(1)提出、分析和设计新的高频（HF）变压器隔离软开关单相和三相功率变换器拓扑结构（单向和双向dc/dc，公用事业接口dc/ac， PMSG和线性发电机高功率因数ac/dc）；(2)开发用于交流/交流直接转换的软开关电子变压器；(3)大功率应用的交错操作；(4)利用INTUSOFT SPICE或PSIM仿真软件对设计的变换器进行性能研究，并构建原型实验变换器。*** *拟议的转换器将减少尺寸和重量（由于高开关频率，低损耗和高频变压器隔离），降低成本，同时满足严格的能源要求。用于风力发电机和海浪发电机的Ac/dc和Ac/ Ac变换器具有高功率因数、低谐波畸变的特点，其中一些将采用高频变压器隔离的单级功率转换。加拿大利用海浪和风能发电的潜力巨大，拟议中的转换器将在此类系统中发挥作用。该计划预计将培养3名电力电子领域的博士，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、模拟和建造方面的培训

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.**