Jean-Christophe Olivier

Optimal sizing of a stand-alone photovoltaic system

The objective of this study is to optimize the sizing of a stand-alone photovoltaic (PV) system. The optimization of the PV energy generated by horizontal panels (or inclined) fixed (or movable) for a given site is realized. The estimation of solar radiation on inclined panels based on the measurements taken on a horizontal plane is presented. Then, an optimization of the inclination angle (tilt angle) is proposed to maximize the annual PV energy production. The energy efficiency of solar tracking system is analyzed and evaluated. Finally, the optimal sizing for the stand-alone photovoltaic system (SAPS) is presented based on an energy management between the PV panels, the batteries, and the load.

Photovoltaic energy for the fixed and tracking system based on the modeling of solar radiation

The objective of this paper is to estimate the photovoltaic energy on inclined panels for a given site. Its characterization is based on measurements carried out on horizontal plane. A comparison of different models of the diffused radiation released with respect to the monthly and annual energy balance is presented. An optimization of the inclination angle (tilt angle) by maximizing the annual photovoltaic energy is proposed. At the end of this study, energy efficiency of different solar tracking systems is also analyzed.

Indirect Synchronization Phenomenon on Self-Oscillating Current Controllers

In this paper, a particular phenomenon called indirect synchronization is investigated on self-oscillating current controllers based on a hysteresis controller and a recent relay- feedback controller without hysteresis. The main effect of this indirect synchronization is a modification of regulation behavior when the system works in high frequency. This study is thus particularly useful for applications such as active filtering or high precision power supply, where the signals to target can be close to the fifth of the switching frequency. Simulation results highlight this indirect synchronization phenomenon and thus show relevance to take it into account for high accuracy applications.

A Nonlinear Phenomenon on Self-Oscillating Current Controllers: The Indirect Synchronization

In this paper, a particular phenomenon called indirect synchronization is investigated on self-oscillating current controllers. This phenomenon appears in medium frequencies, when the reference signal frequency tends to the switching frequency. In a previous work, it has been shown that the indirect synchronization causes discontinuities on the frequential response of the system, making the various linear or continuous models inefficient. For high-accuracy applications, such as active filtering or high-precision power supply, these discontinuities are a real problem. Thus, it seems important to offer an analytical description of this phenomenon. In this paper, an analytical model of the indirect synchronization phenomenon is proposed and checked by simulation and experimental results.

A new compensation technique for PMSM torque ripple minimization

Ensuring torque smoothness is an essential requirement in a wide range of high performance applications based on permanent magnet synchronous machines (PMSM). The reported work proposes a novel technique for the compensation of the torque oscillations essentially caused by the spatial harmonics which can result from the machine design imperfectness or/and the operating uncertainties. The main idea of the proposed method is to modify a conventional PMSM controller by superposing an appropriate compensating signal in the inner current loop. The proposed approach allows minimizing torque ripple through a simple synthesis of the compensating signal and does not require a hard calculation cost. A theoretical analysis and some simulation results are presented to show the effectiveness of the proposed compensating method.

Isolation amplifier for high voltage measurement using a resonant control loop

Some papers describe a novel pulse width modulation, which makes enter converters current control loop in a resonant mode and permits an accurate tracking of the reference. Here, we investigate an analog high voltage measurement board, which implements an isolation amplifier using this modulation strategy. Thus, the isolation amplifier involves an analog-to-digital converter whose operating mode depends on this modulation technique. Then, a linear model of the encoder-decoder is found. The results demonstrate its excellent performances

An Effective Compensation Technique for Speed Smoothness at Low-Speed Operation of PMSM Drives

This paper proposes a simple and effective method to reduce speed ripples of permanent magnet synchronous machines (PMSMs) under low-speed working conditions. The treated issue is related to the periodic torque ripples, which induce speed oscillations that deteriorate the drive performance. The main idea of the proposed method is to modify a conventional PMSM controller by superposing an appropriate compensation signal to the quadratic-current reference. The proposed approach allows the reduction of speed ripples at low speed through a simple compensation signal and does not require a hard calculation cost. A theoretical analysis is presented, and both simulation and experimental results are presented to validate the proposed compensation method.

A Multirate Simulation Method for Large Timescale Systems Applied for Lifetime Simulations

This paper introduces an original approach of the modeling and simulation of multiphysics systems that exhibit a wide range of time scales. This approach will be illustrated by the simulation of the energy storage unit (ESU) of an all-electric ferry. The implementation of the models was performed using two different modeling approaches (causal and acausal) highlighting the main difficulties of modeling multiphysics systems. In order to optimize the sizing of the ESU considering its ageing, the system should be simulated for a lifetime of 20 years. For this purpose, a multirate method was developed to speed-up the simulation and the optimization by a factor of 100 or more.

Global energy optimization of a light-duty fuel-cell vehicle

In this paper, an analytic tank to wheel model of a light-duty fuel-cell vehicle is presented. This model takes into account all the elements of the vehicle along with their interactions. It is used to optimize the velocity profile of the vehicle in order to minimize the energy consumption per kilometer.

A Self Oscillating Voltage Controller for Applications with High Bandwidth

In case of electro-technical body tests, it is necessary to use voltage-controlled converters with large bandwidth and fast dynamics. Recently, a novel pulse width modulation has been investigated. It has permitted to design regulators in order to reach an accurate tracking of current or voltage references. Here, the first version of the voltage controller is improved in order to target these new specifications. Indeed, it is necessary to get a bandwidth of a couple of kiloHertz, with a phase shift lower than ten degrees. This goal is reached