Guillermo R. Bossio

Optimization of power management in an hybrid electric vehicle using dynamic programming

Hybrid electric vehicles are those powered from two different sources. Typically, they are equipped with an internal combustion engine, and also with an electrical storage system, such as a bank of batteries or ultra-capacitors. While braking, these vehicles may convert kinetic energy to electrical energy and send it back to the electrical storage system (regenerative braking). The whole vehicle system may be abstracted to one consisting of two energy sources, one of them rechargeable and the other consumable, that feed or receive energy from an energy consumer. A centralized control strategy is required to define the instantaneous power flows among these three main components. In this work, we derive the power split between the two sources such that fuel consumption is minimized, while the vehicle performs a given velocity cycle. Bounds on the power flows from both sources are considered. There is also a constraint of an integral nature that arises from the fact that the energy of the electrical storage system must remain between proper limits, in order to avoid physical damage. The problem is posed as a finite horizon dynamical optimization problem with constraints and solved by a dynamic programming (DP) approach. The hybrid electrical vehicle being developed in the University of Rio Cuarto, Argentina is taken as the case study.

A 2-D model of the induction machine: an extension of the modified winding function approach

A new method to calculate the inductances of induction machines considering axial nonuniformity is proposed. The proposed method, an extension of the modified winding function approach, allows considering nonuniformity due to skew and static and dynamic air-gap eccentricity. Theoretical fundamentals and experimental results that validate the proposed method are presented.

Separating Broken Rotor Bars and Load Oscillations on IM Fault Diagnosis Through the Instantaneous Active and Reactive Currents

A new method for broken rotor bars and load oscillation diagnosis on induction motors is presented. The proposed strategy is based on the decomposition of the stator currents into their instantaneous active and reactive current components. Such components allow the decoupling of the effects produced by rotor asymmetries from those produced by oscillating loads. This allows not only the proper fault detection but also a correct fault diagnosis. Simulation and experimental results, both from laboratory and industrial cases, are presented to validate the proposal.

A 2D-model of the induction motor: an extension of the modified winding function approach

In this paper, a method to calculate the inductances of an induction machine with axial nonuniformity is presented. The analyzed axial nonuniformities are skew and rotor eccentricities. The inductance calculation is based on an extension of the modified winding function approach. Theoretical fundaments of this extension are presented. The coupled magnetic circuits approach has been used for modeling the induction machine. Experimental results that validate the proposal are also presented.

Effects of rotor bar and end-ring faults over the signals of a position estimation strategy for induction motors

The effect of rotor faults, such as broken bars and end rings, over the signals of a position estimation strategy for induction motor drives is analyzed using a multiple coupled circuit model. The objective is to establish the possibility of using the estimation strategy signals for fault diagnosis in variable speed electric drives. This strategy is based on the effect produced by inductance variation on the zero sequence voltage, exciting the motor with a predefined inverter-switching pattern. Experimental results illustrate the feasibility of the proposal.

Effects of partial rotor demagnetization on permanent magnet synchronous machines

The effects of magnet faults on the rotor of permanent magnet synchronous machines are analyzed in the present work. In particular, demagnetization effects are analyzed using the finite element method. Two different stator winding configurations are considered in the analysis, series and parallel connected windings. From this analysis, a fault detection strategy based on the information contained in winding-current spectrum is proposed. A fault severity factor is also proposed to quantify residual magnetism losses (demagnetization) on a single magnet. This factor is practically independent from the motor load conditions. Experimental results are presented to validate the proposal.

Evaluation of harmonic current sidebands for broken bar diagnosis in induction motors

Effects of rotor faults on stator currents in induction motors are studied in the present work. Particularly, the effects of such faults on the sidebands at fundamental and harmonics current components are analyzed. A multiple-coupled circuit model determines the variation of amplitude of these sidebands as a function of the number of broken bars, load and motor-load inertia. The results obtained from this analysis allow improving the rotor fault diagnosis techniques and identifying and separating rotor faults from others. Simulation and experimental results are presented to validate the proposal.

Broken bar detection in single-phase reciprocating compressors

Broken rotor bar detection in induction motors using current signature analysis gives good results when the motor load is almost constant. However, if the load torque is oscillating, or it is a function of the rotor position, the current spectrum will contain spectral components which coincides with the components produced by rotor faults. Thus, rotor fault detection in these loads, such as compressors and other reciprocating loads, is very difficult. A new strategy for broken rotor bar diagnosis in single-phase induction motors is presented in this paper. This strategy is based on the analysis of the auxiliary winding voltage. The proposed strategy allows the diagnostic of rotor faults even with pulsating load torque. Simulation and experimental results are presented.

Angular misalignment in induction motors with flexible coupling

The problem of angular shaft misalignment in motors-load systems coupled through flexible couplings is analyzed in this work. A model for the analysis and diagnosis of angular misalignment in induction motors is presented. It allows studying the angular shaft misalignment effects over the motor torque, instantaneous power and currents through dynamic simulation. Additional effects introduced by the mixed eccentricity produced by the shaft misalignment are also analyzed through experiments. The results show that angular misalignment can be detected from electrical motor variables, but its correct diagnosis is difficult. The study is completed by vibration and thermography analysis.

Model Based Stator Fault Detection in Induction Motors

A new strategy for stator fault diagnosis in induction motors is presented in this paper. The proposed strategy is based on the generation of a vector of specific residual using a state observer. The residual allows the detection of the faulted motor phase and the quantification of the number of shortcircuited turns. This strategy is robust to motor load variation and power supply perturbations