Adrian Florescu

Hardware-in-the-loop testing of PV control systems using RT-Lab simulator

This paper presents a testing system for power converters control units. A hardware-in-the-loop test bench is designed for assessing control unit performances. A photovoltaic generator, coupled with a boost circuit, is software-simulated within a real-time environment, RT-Lab and coupled in closed loop with the physical control unit to be tested.

Frequency-separation-based energy management control strategy of power flows within electric vehicles using ultracapacitors

This paper deals with a frequency-based energy sharing method between batteries and ultracapacitors (UC) as power sources within an electric vehicle (EV). A frequency splitter is used for routing the low-frequency content of power demand into the battery and its high frequencies into the UC system, taking profit from the UC as a peak power unit. The autonomy may thus be increased while also preserving the battery life. Real-time experiments on a dedicated test rig validate the proposed energy management approach.

Load rates of low voltage transformers and medium voltage profile assessments on a real distribution electric grid based on average Daily Load Profile (DLP) of a housing for a high penetration of plug-in hybrid electric vehicles (PHEVs)

This paper assesses the impact of PHEVs on a real medium voltage distribution electric grid based on average Daily Loads Profiles (DLPs) of a PHEV and of a housing. For three penetration rates, we show the important effects on load rates of low voltage transformers which compose the studied urban substation. Nevertheless, we demonstrate the robustness of medium voltage electric grid for the high penetration of PHEVs because the ηV index proposed which assess the quality of the voltage supplied to low voltage transformers reached a minimum of 98.2%.

Voltage profile and excess subscription assessments indexes based on random selection of real Daily Loads Profiles (DLPs) on residential electric grid areas for a high penetration of Plug-in Hybrid Electric Vehicles (PHEVs)

The Plug-in Hybrid Electric Vehicles (PHEVs) will strongly penetrate in the coming years. Based on domestics Daily Loads Profiles (DLPs) models generator and probabilistic algorithm of PHEVs connections, this paper assesses the impact of PHEVs on a typical residential low voltage electric grid of 96 houses. For this purpose, two indexes are proposed in order to assess the limits of PHEVs penetration rate, the ηD for excess subscription contracts and ηV index for voltage drop. For the considered electric grid, a massive deployment of PHEVs without management increase the risk of excess subscriptions because index proposed decreases to 87% in summer and 78.8% in winter for houses without electric heating. The ηD index reaches a minimum of 76.5% in winter for houses with electric heating. Finally, the voltage profile of this electric grid is very impacted because the ηV index proposed decrease to 85.8% in summer and 81% in winter.

Energy Management System within Electric Vehicles Using Ultracapacitors: An LQG-optimal-control-based Solution

Abstract This paper proposes a frequency-separation-based energy management inside of electric vehicles using ultracapacitors as high-energy-density auxiliary power sources. The power sources are enabled to share the stochastically-variable load according to their features: low-frequency variations of the required power are ensured by the main source, the battery, whereas high-frequency variations are provided by the ultracapacitor. An LQG-based optimal control structure is designed and coupled with a gain-scheduling law to cover the entire operating range; it conveniently trades off the load regulation performance and the variations of battery current, in order to improve the battery reliability and lifetime. MATLAB®/Simulink® numerical simulations reveal good results for strongly variable driving cycles.

Energy management system for hybrid electric vehicle: Real-time validation of the VEHLIB dedicated library

This paper deals with the energy share between batteries and supercapacitors within hybrid electric vehicles (HEV). A library of models, known as Hybrid Electric Vehicle Library (VEHLIB), which combines the different models to form a coherent modular base, has been constructed and implemented in real time simulator. Real-time results are here discussed in order to illustrate the effectives of models used. The integration of the on-board energy source of an electrically propelled vehicle with a supercapacitor bank (SB) as a peak power unit, can lead to substantial benefits in terms of electric vehicle, battery life and energy economy. An energy management strategy is also suggested, which is based upon the DC bus voltage regulation.

LQG Optimal Control Applied to On-Board Energy Management System of All-Electric Vehicles

This paper proposes a general frequency-separation-based strategy of coordinating power sources within off-grid applications. The application chosen to illustrate this strategy is an electric vehicle equipped with two power sources-a battery and an ultracapacitor (UC)-for which coordination problem can be formulated and solved as a linear quadratic Gaussian (LQG) optimal control problem. The two power sources are controlled to share the stochastically variable load according to their respective frequency range of specialization: low-frequency variations of the required power are supplied by the main source, the battery, whereas high-frequency variations are provided by the UC. The studied system is a bilinear one; it can be modeled as a linear parameter varying system. An LQG-based optimal control structure is designed and coupled with a gain-scheduling structure to cover the entire operating range. In this way, load regulation performance and the variations of battery current are conveniently traded off to preserve battery reliability and lifetime. Real-time experiments on a dedicated test rig-based on employing a real UC-validate the proposed optimal power flow management approach.

PHIL simulation for validating power management strategies in all-electric vehicles

In this paper a power hardware-in-the-loop (PHIL) structure for testing algorithms for the management of power flows in all-electric vehicles is presented. Its complex structure, comprising both real-time simulators and control structures, covers the entire electromechanical power chain. It is based upon real-time platforms (DSPACE and RT-LAB) interacting with dedicated hardware equipments, thus enabling the replication of driving conditions and driver actions, as well as power sources emulation and DC-link control. Successful real-time tests that validate control algorithms for electrical power flow sharing in a complex all-electrical vehicle have been performed on this platform.

Protection devices testing based on power-hardware-in-the-loop simulation

Low-voltage circuit breakers are vital elements in order to insure the low-voltage power systems security. As nowadays the loads connected in these power systems are characterized by a strong non-linearity, inrush currents or high harmonic pollution can cause circuit breakers false tripping. In this context, it is necessary to study the interaction between these newer loads and the protection devices. Thus, this paper deals with a new test procedure for switching devices, based on power hardware-in-the-loop real-time simulation. The goal of this procedure is the test of a real circuit breaker while the power system is emulated by the real-time simulator. The new test procedure was validated via experimental test.