Hierarchical Control for Electro-Thermal Power Management of an Electric Vehicle Powertrain

Author(s):  
Donald J. Docimo ◽  
Herschel C. Pangborn ◽  
Andrew G. Alleyne

This paper develops a hierarchical control framework to manage both the electrical and thermal domains of an automotive electric vehicle (EV). Batteries, electric machines, and power electronics all have desired thermal operating ranges, with operation outside these limits leading to reduced component performance and lifespan. Previous studies present various component- and high-level energy management algorithms that seek to maintain desired temperatures. However, the literature contains limited efforts to develop comprehensive control approaches that coordinate the electrothermal dynamics within the vehicle, ensuring that electrical systems do not generate more thermal energy than can be managed within temperature constraints. To address this gap, this paper presents a hierarchical control framework that governs electrical and thermal states across multiple timescales while meeting operational requirements, such as tracking a desired vehicle velocity and cabin temperature. To develop this framework, a network of communicating model predictive controllers coordinates the system dynamics, with significant reduction in computational complexity over a centralized control approach. A graph-based model of the candidate EV powertrain is developed and then decomposed to generate models used in each controller of the hierarchical framework. Through the case study of this paper, it is demonstrated that the hierarchical controller can make important trade-offs between tracking desired operational references and maintaining temperatures within constraints.

Author(s):  
Matthew A. Williams ◽  
Justin P. Koeln ◽  
Andrew G. Alleyne

This two-part paper presents the development of a hierarchical control framework for the control of power flow throughout large-scale systems. Part II presents the application of the graph-based modeling framework and three-level hierarchical control framework to the power systems of an aircraft. The simplified aircraft system includes an engine, electrical, and thermal systems. A graph based approach is used to model the system dynamics, where vertices represent capacitive elements such as fuel tanks, heat exchangers, and batteries with states corresponding to the temperature and state of charge. Edges represent power flows in the form of electricity and heat, which can be actuated using control inputs. The aircraft graph is then partitioned spatially into systems and subsystems, and temporally into fast, medium, and slow dynamics. These partitioned graphs are used to develop models for each of the three levels of the hierarchy. Simulation results show the benefits of hierarchical control compared to a centralized control method.


2020 ◽  
Vol 12 (10) ◽  
pp. 4264 ◽  
Author(s):  
Younès Dagdougui ◽  
Ahmed Ouammi ◽  
Rachid Benchrifa

This paper presents a smart building energy management system (BEMS), which is in charge of optimally controlling the sustainable operation of a building-integrated-microgrid (BIM). The main objective is to develop an advanced high-level centralized control approach-based model predictive control (MPC) considering variations of renewable sources and loads. A finite-horizon planning optimization problem is developed to control the operation of the BIM. The model can be implemented as a BEMS for the BIM to manipulate the indoor temperature and optimize the operation of the system’s units. A centralized MPC-based algorithm is implemented for the power management scheduling of all sub-systems as well as power exchanges with the electrical grid. The MPC algorithm is verified over case studies applied to two floors residential building considering the climate condition of a typical day of March, where the effects of both loads and thermal resistance of building shell on the operation of the BIM are analyzed via numerical simulations. The analysis shows that 96% of the total electrical load has been fulfilled by the local production where 23% represents the total electric output of the micro-CHP and 73% is the renewable energy production. The deficit, which represents only 4%, is purchased from the electrical distribution network (EDN).


Author(s):  
Justin P. Koeln ◽  
Matthew A. Williams ◽  
Andrew G. Alleyne

This two-part paper presents the development of a hierarchical control framework for the control of power flow throughout mobile systems. These vehicles are comprised of multiple interconnected systems each with multiple subsystems which exhibit dynamics over a wide range of timescales. These interconnections and the timescale separation pose a significant challenge when developing an effective control strategy. Part I presents the proposed graph-based modeling approach and the three-level hierarchical control framework developed to directly address these interconnections and timescale separation. The mobile system is represented as a directed graph with vertices corresponding to the states of the vehicle and edges capturing the power flow throughout the vehicle. The mobile system and the corresponding graph are partitioned spatially into systems and subsystems and temporally into vertices of slow, medium, and fast dynamics. The partitioning facilitates the development of models used by model predictive controllers at each level of the hierarchy. A simple example system is used to demonstrate the approach. Part II utilizes this framework to control the power flow in the electrical and thermal systems of an aircraft. Simulation results show the benefits of hierarchical control compared to centralized and decentralized control methods.


1973 ◽  
Vol 12 (1) ◽  
pp. 1-30
Author(s):  
Syed Nawab Haider Naqvi

The recent uncertainties about aid flows have underscored the need for achieving an early independence from foreign aid. The Perspective Plan (1,965-85) had envisaged the termination of Pakistan's dependence on foreign aid by 1985. However, in the context of West Pakistan alone the time horizon can now be advanced by several years with considerable confidence in its economy to pull the trick. The difficulties of achieving independence from foreign aid can be seen by reference to the fact that aid flows make it possible for the policy-maker to pursue such ostensibly incompatible objectives as a balance in international payments (i.e., foreign aid finances the balance of payments), higher rates of economic growth (Lei, it pulls up domestic saving and investment levels), a high level of employment (i.e., it keeps the industries working at a fuller capacity than would otherwise be the case), and a reasonably stable price level (i.e., it lets a higher level of imports than would otherwise be possible). Without aid, then a simultaneous attainment of all these objectives at the former higher levels together with the balance in foreign payments may become well-nigh impos¬sible. Choices are, therefore, inevitable not for definite places in the hierarchy of values, but rather for occasional "trade-offs". That is to say, we will have to" choose how much to sacrifice for the attainment of one goal for the sake of somewhat better realization of another.


Author(s):  
Ahmed Khalil ◽  
Nicolas Fezans

AbstractGust load alleviation functions are mainly designed for two objectives: first, alleviating the structural loads resulting from turbulence or gust encounter, and hence reducing the structural fatigue and/or weight; and second, enhancing the ride qualities, and hence the passengers’ comfort. Whilst load alleviation functions can improve both aspects, the designer will still need to make design trade-offs between these two objectives and also between various types and locations of the structural loads. The possible emergence of affordable and reliable remote wind sensor techniques (e.g., Doppler LIDAR) in the future leads to considering new types of load alleviation functions as these sensors would permit anticipating the near future gusts and other types of turbulence. In this paper, we propose a preview control design methodology for the design of a load alleviation function with such anticipation capabilities, based on recent advancements on discrete-time reduced-order multi-channel $$H_\infty $$ H ∞ techniques. The methodology is illustrated on the DLR Discus-2c flexible sailplane model.


Author(s):  
Iram Akhtar ◽  
Sheeraz Kirmani ◽  
Shaheen Hasan ◽  
Sabah khan

2019 ◽  
Vol 9 (15) ◽  
pp. 3052
Author(s):  
Jiafu Yin ◽  
Dongmei Zhao

Due to the potential of thermal storage being similar to that of the conventional battery, air conditioning (AC) has gained great popularity for its potential to provide ancillary services and emergency reserves. In order to integrate numerous inverter ACs into secondary frequency control, a hierarchical distributed control framework which incorporates a virtual battery model of inverter AC is developed. A comprehensive derivation of a second-order virtual battery model has been strictly posed to formulate the frequency response characteristics of inverter AC. In the hierarchical control scheme, a modified control performance index is utilized to evaluate the available capacity of traditional regulation generators. A coordinated frequency control strategy is derived to exploit the complementary and advantageous characteristics of regulation generators and aggregated AC. A distributed consensus control strategy is developed to guarantee the fair participation of heterogeneous AC in frequency regulation. The finite-time consensus protocol is introduced to ensure the fast convergence of power tracking and the state-of-charge (SOC) consistency of numerous ACs. The effectiveness of the proposed control strategy is validated by a variety of illustrative examples.


2014 ◽  
Vol 663 ◽  
pp. 532-538
Author(s):  
Nor Aziah Mohd Azubir ◽  
Mohd. Khair Hassan ◽  
Hairi Zamzuri ◽  
Saiful Amri Mazlan

There are many types of Electric Vehicle (EV) applied in automotive industry. It can be hybridization or electrification vehicle. Battery Electric Vehicle (BEV) also called as fully electric vehicle using batteries as the only source and an electric motor as a traction motor to move the vehicle. In a world view of BEV, it is still has circumstances that would strand the BEV to have huge commercialization due to range anxiety. This paper is discussing about an electrification vehicle power and energy management (PEM) strategy. PEM strategy has two layer control strategies that consist of low level component control and high level supervisory control. Management and control strategy in BEV is carefully designed due to heavy loads consumption from Propulsion Electrical Load (PEL) and Non Propulsion Electrical Loads (NoPEL) with a single energy source. This is to ensure that power and energy is managed at optimum level that will give some extension of wider kilometer of the vehicle. The BEV performance is typically controlled by high level supervisory control algorithm using event-based condition using state machine deterministic rule-based method. More than one drive mode to be determined in this paper as part of control strategy to get an optimal PEM performance.


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