Medium Voltage DC Systems in Electricity Distribution Networks

描述：太阳能光伏和储能系统已被广泛认为是解决能源和环境问题的最有效方法之一。需要几个电力电子转换器来管理从太阳能光伏板到储能和电网的功率流。因此，这种转换器可以决定太阳能储能系统的整体性能，例如效率和功率密度。最近提出了许多控制方法、拓扑结构和调制策略，以提高转换器的功率密度、效率、可靠性和成本。然而，两大挑战仍然是进一步推进这些目标的关键障碍。第一个挑战是用于减少电压波动的笨重的电解电容器，这是转换器中最脆弱的部件。它们可以导致大约30%的故障，并且在小型电源转换器中占据83%的体积。第二个挑战是用于隔离泄漏电流的效率低下且体积庞大的隔离变压器。在一台6kw的光伏逆变器中，这种变压器约占系统功率损耗的3%，重量的60%以上，体积的50%以上。在这个项目中，我们的目标是通过1)先进的电源拓扑设计，去除隔离变压器和电解电容器，为太阳能光伏储能系统开发一个5kw的高效，可靠和小型的变换器系统；2)设计高频电感，减小系统体积和重量；3)控制系统设计，改善系统动力学；4)所研制电源变换器的仿真与实验验证。随着Solar Ready Solutions的承诺，开发的转换器的商业化路线将作为该项目的一部分。

EPSRC Portfolio Areas: Energy storage, Solar technologyDescription:Solar PV and energy storage systems have been widely recognised as one of most effective ways to address energy and environmental issues. Several power electronic converters are required to manage the power flow from solar PV panels to energy storage and power grid. As a result, such converters can determine the overall performance, e.g., efficiency and power density, of the solar energy storage system.Numerous control methods, topologies, and modulation strategies have been recently proposed to improve power density, efficiency, reliability, and costs of the converters. However, two major challenges remain as critical obstacles to further advance these. The first challenge is the bulky electrolytic capacitors used to reduce voltage ripples, which are the most vulnerable components in the converters. They can cause about 30% of failures, and occupy 83% of the volume in a small power converter. The second challenge is the inefficient and bulky isolation transformers used to isolate leakage currents. Such transformers can account for about 3% of system power losses, over 60% of weight, and over 50% of volume in a 6 kW PV inverter. In this project, we aim to develop a 5 kW highly efficient, reliable and small-sized converter system for solar PV energy storage systems through 1) advanced design of power topologies to remove isolation transformers and electrolytic capacitors; 2) design of high-frequency inductors to reduce system size and weight; 3) control system design to improve system dynamics; 4) simulation and experimental verification of the developed power converters. With the commitment from Solar Ready Solutions, routes to commercialization of the developed converters will be included as a part of this project.