Cherif Larouci

Two Active Fault-Tolerant Control Schemes of Induction-Motor Drive in EV or HEV

In this paper, two active fault-tolerant control (AFTC) schemes dedicated to induction-motor drives in electric or hybrid vehicle powertrains are presented and compared. Fault detection and mitigation are merged to propose a robust algorithm against speed-sensor faults (fault is modeled as significant additional noise or an exponential type emulating a bias) leading to uncertainties in the measurement. The first architecture is a hybrid fault tolerant-control (FTC) with proportional-integral and H∞ controllers; the second architecture is the generalized internal model control (GIMC) with a natural reconfiguration. Both are built to ensure resilience while keeping good dynamic performances. For each architecture, the speed-sensor fault detection is based on an extended Kalman filter (EKF) that generates a residual vector. The correction method is calculated differently for the two schemes specifically in the switching transition phase between the nominal and robust controllers. A comparative study is carried out between the two FTC schemes.

Presizing Methodology of DC–DC Converters Using Optimization Under Multiphysic Constraints: Application to a Buck Converter

This paper presents an approach to presize dc-dc converters. This approach is carried out in three main steps. The first one helps the designer to select the most adapted architecture answering the specifications and appropriate technologies of passive and active components of the selected architecture minimizing a major constraint (like volume or cost). Models used in this step are developed from manufacturer datasheets. The second step consists on optimizing the selected architecture by considering the appropriate technologies resulting from the first step under multiphysic constraints: thermal, losses (or efficiency), volume, and electromagnetic compatibility. Analytical models to consider the different constraints are developed. The third step carries out a second optimization with integration of a finite element simulation. It allows refining the optimization results of the second step and consists on optimizing the components placement under thermal and EMC constraints together or separately. The developed methodology proposes a progressive approach to answer industrial needs when presizing power converters. It allows reducing significantly the computing time which is suitable in a presizing phase where several parameters must be optimized and multiphysic constraints must be respected.

Design of Power Converters by Optimization Under Multiphysic Constraints: Application to a Two-Time-Scale AC/DC–DC Converter

The aim of this paper is to present an optimization-under-constraints approach to design power converters. In fact, the time-domain simulation is very useful to evaluate the performances of power converters when the design solution area of the studied converter is much reduced due to the designers experience and when only few design aspects are considered. However, the design of todays power converters is more and more complicated because it needs to consider multiphysic and multidomain constraints. In this context, a design approach using optimization under constraints allows exploring a large solution area by considering the multiphysic aspect and a high number of optimization parameters. In this way, this paper proposes the use of analytical models to carry out a compromise between the model accuracy and the computing time when optimizing power converters under volume, electromagnetic compatibility, efficiency, thermal, and control constraints. This approach is applied to optimize a two-time-scale flyback converter. The optimized converter is implemented, and the proposed approach is validated by measurements.

Optimization of a 42V/14V dc-dc converter for vehicular electrical network

The aim of this paper is to present an analytical optimization approach of a 42V-14V converter for the automotive domain. Indeed, the amount of electronic equipment on board of vehicles and the electrical power requirement of motorcars has increased steadily during the past 50 years, starting at about 100 W in 1950 reaching 2 kW in 2000, it will reach 5 kW in 2010. The 14V network is not able to supply enough current for the increasing power requirement. So, a 42V network is generalized [J.G. Kassakian, February 2000]. A special dc/dc converter is therefore needed to interconnect these two networks [M. Hasebe], [C. Larouci et al.], [C. Larouci et al.]. In this context, the paper develops an analytical optimization methodology under constraints of a 42V-14V dc-dc converter. It recommends the use of analytical models to optimize the passive element volume by respecting EMC standards, by minimizing the whole dissipated losses, by constraining the semiconductor junction, the winding and the magnetic circuit temperatures and by insuring the controlled converter stability and a good dynamic performances. The developed optimization procedure is validated by numerical simulation and measures.

H-infinity robust control of 3-DOF helicopter

This paper proposes a robust control technique for a 3-DOF helicopter. The control algorithm uses a robust controllers synthesized by the H infinity loop shaping approach. The simulation results show that the robust controllers stabilize the system and reject the disturbances. The evaluate and the comparative studies between the classical controllers (PI, PD, PID) and the robust H infinity loop shaping controller are given with simulations results in presence of the noise disturbance in the closed loop control of the elevation, pitch and rotation.

A new pre-sizing approach of DC-DC converters, application to a boost converter for the automotive domain

This paper presents a pre-sizing approach of DC-DC converters. This approach is carried out in two main steps. The first step consists on determining the most adapted architecture to answer the specifications and the appropriate technologies of the passive and the active components of the selected architecture representing the minimal volume. The technology choice is carried out using models developed from manufacturer datasheets. The second step consists on optimizing the selected architecture by considering the appropriate technologies resulting from the first step under multi-physic constraints: thermal, losses (or efficiency), volume and electromagnetic compatibility constraints …. The proposed approach allows reducing significantly the computing time which is suitable in a pre-sizing phase where several parameters must be optimized and multi-physic constraints must be respected.

Fault tolerant control to mechanical sensor failures for Induction Motor drive: A comparative study of voting algorithms

In this paper, we present a comparative study of four voting algorithms for two Induction Motor drive fault tolerant control to speed sensor failure schemes. In both Output and Input Fault Tolerant controller, the voting algorithm chooses the most appropriate output signal to ensure the best behavior in degraded mode. The performances are evaluated through simulations of a 7.5 kW Induction Motor drive with robustness testing against parametric variations, as well as under load testing. The results show that Euler, Newton-Raphson and Maximum Likelihood voting algorithms are more efficient than the Weighted Average in both Fault Tolerant Control schemes.

Modeling and Control of the Vehicle Transmission System Using Electric Actuators; Integration of a Clutch

The aim of this paper is to present a method to carry out an electrical simulator of the vehicle transmission chain including a clutch by using electric actuators controlled thanks to a dedicated torque control laws. It proposes an equivalent electrical system to the vehicle transmission chain. This equivalent system is easily exploited and can operate under a reduced power scale. This equivalent system allows to carry out various tests on manual, automatic or robotized gearboxes, on clutch or heat engine. Moreover, it allows to carry out a vehicle test benches by optimizing the cost and the time of the development phase of the vehicle transmission system. The proposed method is validated by numerical simulation and measures.

Optimal design of a synchronous DC-DC converter using analytical models and a dedicated optimization tool

The aim of this paper is to present an optimization approach of static converters using analytical models and a dedicated tool. Indeed, tools like Saber, Pspice or Simplorer are effective means for the power electronics structure time-domain studies. However, if these structures have an ac input and a high switching frequency (various time scales), or if several aspect studies are taken into account, time-domain simulation becomes painful and expensive in memory and computing time. The study of electromagnetic compatibility (EMC) performances is also difficult because of the line impedance stabilizer network (LISN) time-constants which come to penalize the time-domain simulation. In addition, in sizing and optimization process, results in short computing times are needed, so the time-domain simulation may be too time consuming. In this way, the paper proposes to carry out a compromise between the model accuracy and the tool rapidness and recommends the use of analytical models to optimize the passive element volume of static converters by respecting EMC standards, by minimizing the whole dissipated losses (conduction and switching semiconductor losses, core and copper inductor losses, capacitor losses) and by constraining the semiconductor junction, the winding and the magnetic circuit temperatures. This optimization approach is applied to a 42 V-14 V dc-dc converter for the automotive domain (output power 1 kW). The developed optimization procedure is validated by numerical simulation and measures.

Experimental H-infinity robust control of aerial vehicle flight

This paper proposes and evaluates the comparative studies between the classical controllers (PI, PD and PID) with H∞ robust control technique for an 3-DOF helicopter. The control algorithm uses a robust controllers synthesized by the H∞ loop shaping approach. The experimental results show that the robust controllers stabilize the system and reject the disturbances when the system is subjected to uncertainties of a norm lower than the maximum stability margin.