Multi-Objective Optimization of a Hybrid ESS Based on Optimal Energy Management Strategy for LHDs

Abstract

Abstract:Energy storage systems (ESS) play an important role in the performance of mining vehicles. A hybrid ESS combining both batteries (BTs) and supercapacitors (SCs) is one of the most promising solutions. As a case study, this paper discusses the optimal hybrid ESS sizing and energy management strategy (EMS) of 14-ton underground load-haul-dump vehicles (LHDs). Three novel contributions are added to the relevant literature. First, a multi-objective optimization is formulated regarding energy consumption and the total cost of a hybrid ESS, which are the key factors of LHDs, and a battery capacity degradation model is used. During the process, dynamic programming (DP)-based EMS is employed to obtain the optimal energy consumption and hybrid ESS power profiles. Second, a 10-year life cycle cost model of a hybrid ESS for LHDs is established to calculate the total cost, including capital cost, operating cost, and replacement cost. According to the optimization results, three solutions chosen from the Pareto front are compared comprehensively, and the optimal one is selected. Finally, the optimal and battery-only options are compared quantitatively using the same objectives, and the hybrid ESS is found to be a more economical and efficient option.

Optimization of Hybrid Energy Storage Systems for Vehicles with Dynamic On-Off Power Loads Using a Nested Formulation

“…The HESS design optimization for an LHD is used to illustrate the newly proposed method. In addition, compared to the optimal solution selected from Pareto front in our prior work [8], the solution obtained in this paper has more advantages, including fewer life-cycle cost and replacement cost as well as longer working hours, which indicates that the proposed method can achieve a better solution. The remainder of this paper is organized as follows: in Section 2, the adequate architecture of the HESS for the LHD application is identified and the performance and power-loss model of the HESS is introduced.…”

“…The batteries are connected directly to the DC bus for maintaining its voltage because the battery voltage only changes slightly during operation comparing to the UC. This topology has the ability to use the UCs more effectively compared to passive parallel topology and has relatively low cost and high efficiency compared to fully active topology, and the UCs are used in complementary to reduce the peak power and to extend the operation life of the batteries [8,35]. In practice, electric accessories (ACC) also need to be powered by the HESS, and these accessories usually have stable energy consumption.…”

“…As for the design space, DOD BT from 50% to 80% is added as a new continuous variable compared to our work in [8]. N BT belongs to an even number from 170 to 200 due to the working range of the DC bus (400 V-720 V) as well as for easy arrangement.…”

“…These variant power flow in and out of the ESS are either due to the direct power demands from a PEV or caused by the need from a hybrid electric vehicle (HEV) to allow its internal combustion engine (ICE) to work at relatively constant speed and torque outputs for higher fuel efficiency. These dynamically changing loads impose negative impacts on battery life, thereby increasing the LCC of the ESS and the EVs [7,8]. To better serve the rapidly growing PEV and PHEV markets, lower battery ESS LCC and extended operation life are demanded.…”

Methodology for the Optimisation of Battery Hybrid Energy Storage Systems for Mass and Volume Using a Power-To-Energy Ratio Analysis

“…Conversely, a HESS that is designed for a vehicle is significantly more dependent on mass and volume and is critical for both packaging and performance. In general, HESSs in vehicles can include electrical, chemical and mechanical storage systems, including batteries, fuel cells, flywheels and ultracapacitors [16][17][18][19][20][21][22][23][24]. Recently, more research has been focused on their implementation in vehicles, covering a variety of applications, such as city buses, tramways, passenger cars and construction machinery.…”