Improvement of Electric Vehicles Performance using Energy Storage Systems with High Specific Power

电气化动力总成系统对开发节能电动汽车产生了极大的兴趣。储能系统(ESS)是实现更高续航里程、更好的爬升或加速能力以及提高能源效率的核心。目前，电动汽车广泛使用电池，但为了获得可接受的行驶里程，通常首选高比能量(HSE)电池，但其比功率通常较低(~1kW/kg)。最近的发展趋势表明，锂离子电容器或超级电容器(SCs)等具有潜在潜力的新型电池系统已经被开发出来，以提供高比功率(~12kW/kg)。这些系统可以解决主能量电池组合在一起时的部分快速退化，并通过更有效地存储制动能量来增加行驶里程。它们的控制是一个双重挑战，因为它需要高性能的转换器和智能管理。我研究的长期愿景是开发性能良好、可靠且具有成本效益的能源转换和交通运输ESSS，以降低总体化石燃料消耗。自2008年以来，我的研究主要集中在多ESS电动汽车(电池和SC)的实时能量共享策略上，以提高驾驶循环结束时的全局性能。同时，我研究了可变电感(VI)的概念，以解决用于高功率传输的功率电感的饱和问题，表现出相当大的磁性材料减少，具有更好的效率和功率密度。作为上述研究的加强，本次发现拨款(DG)的总体目标是证明，通过改进的基于可变电感(VI)的功率转换器耦合的HSP-ESSS，在智能多目标能量管理算法的正确协调下，可以提高全局效率和电动汽车的驱动性能。为了实现这一目标，在一个扩展的跨学科挑战下，我将追求以下三个具体目标：1)分析HSP-ESS的能效，以及基于VI的转换器的具体使用，包括其设计和实现；2)使用新定义的优点指标，研究HSP-ESS的添加对主要ESS性能的影响；3)开发包含多个目标函数的算法，其中不同程度的重要程度作为一些外部变量(交通、用户需求、天气条件等)的函数来分配，以解决驾驶周期功率需求的随机特性。该方法的创新之处在于使用虚拟仪器的概念来：1)开发更高效、更小、更轻的DC/DC转换器；2)定义多目标算法以更好地将HSP-ESSS集成到电动汽车中，以同时解决两个主要挑战：多ESS的能量管理和VI的控制复杂性。

Electrified powertrain systems have gained a significant interest to develop energy-efficient Electric Vehicles (EVs). Energy Storage System (ESS) is central to reach higher driving range, better climbing or acceleration capabilities, and increased energy efficiency. Currently, batteries are widely-used in EVs, but to obtain an acceptable driving range, batteries with High Specific Energy (HSE) are typically preferred but their specific power is normally low (~1kW/kg). Recent trends suggest that new battery systems with promising potential as Li-Ion capacitor or SuperCapacitors (SCs) have been developed to give High Specific Power (HSP) (~12kW/kg). These systems could address part of the fast degradation of the main energy battery when coupled together, and increase the driving range by storing the braking energy more efficiently. Their control is a double challenge because it demands a high performance converters and an intelligent management. The long-term vision of my research is to develop performant, reliable and cost-effective energy conversion and ESSs for transport that will reduce overall fossil fuel consumption. Since 2008, my research has focused on the real time power sharing strategies for a multi-ESS EVs (battery and SCs) for increasing the global performance at the end of the driving cycle. In parallel, I have studied the Variable Inductor (VI) concept to solve the saturation issues of power inductors for high power transfers showing a considerable reduction of magnetic material, with better efficiency and power density.As an enhancement of the aforementioned research, the general objective of this Discovery Grant (DG) is to demonstrate that HSP-ESSs coupled through improved VI-based power converters, correctly coordinated by an intelligent multi-objective energy management algorithm, may increase the global efficiency and the driving performance of EVs. To achieve this goal, under an extended interdisciplinary challenge, I will pursue the following 3 specific objectives: 1) to analyze the energy efficiency of HSP-ESS, with the specific usage of VI-based converters, including theirs design and implementation; 2) to study the impact on the main ESS performance with the addition of the HSP-ESSs, using a new defined indicator of merits; 3) to develop algorithms encompassing multiple objective functions to which different degrees of importance are assigned as a function of some exogenous variables (traffic, user requirements, weather conditions, etc.), to address the random nature of the power demand of the driving cycle.The novelty of the proposed approach is to use the VI concept in order: 1) to develop more efficient, smaller and lighter DC/DC converters; and 2) to define multi-objective algorithms to better integrate the HSP-ESSs into the EV to address simultaneously two main challenges: the energy management of multi-ESS and the control complexity of the VI.