Speed Sensor Faults Research Articles

Application of Speed, Rotor Flux, Electromagnetic, Load Torque Observers and Diagnostic System in a Vector-Controlled High-Power Traction Motor Drive

For a field-oriented high-power induction motor drive, the observers are used to calculate speed, rotor flux phase and amplitude, electromagnetic and load torque observation and control and for diagnostic purposes. The observers of speed, rotor flux phase and amplitude are designed based on the model reference adaptive system, which has simple structure but extreme precision. A load torque observer is planned by employing the speed and electromagnetic observers, which well estimates the actual load torque. A diagnostic system is proposed to send an alarm to the maintenance center during the fault occurrence by independently comparing the observed and the actual or the previously recorded values of the load torque and speed. In addition, the drive control can be switched automatically to sensorless mode during the system operation, as a speed sensor fault occurs. Generally, the application of the observers and diagnostic system increases the drive reliability and safety. The performances of the drive, observers and diagnostic system are verified through simulations accomplished on a 150-kW induction motor drive.

Fault-tolerant cruise control of electric vehicles with induction motors

A fault-tolerant control scheme is proposed for the cruise control of electric vehicles (trains, cars) that make use of induction motors. It relies on a rotor speed reference generator and on a flux observer which is adaptive with respect to the uncertain rotor and stator resistances and to the load torque as well. The closed loop on-line identification of those three critical uncertain parameters allows for: (i) on-line estimating and imposing the motor flux modulus reference value which minimizes power losses at steady-state and improves power efficiency; (ii) the on-line detection of speed sensor faults as well as the fast switching on redundant motor speed sensors. CarSim simulations illustrate the effectiveness of the proposed approach.

An FTC Approach to Wind Turbine Power Maximisation via T-S Fuzzy Modelling and Control

This paper presents a new strategy for offshore wind (OSW) turbine active sensor fault-tolerant control (FTC) to optimise the wind energy captured by a wind turbine operating at low wind speed via Takagi-Sugeno (T-S) multiple models with effective wind speed (EWS) estimation. The FTC strategy uses the proportional multiple integral observer (PMIO) as intermediate block between the system and the controller to provide (1) an estimation of the generator and/or rotor speed sensor(s) faults to compensate (hide) their effects from the T-S fuzzy dynamic output feedback controller (TSDOFC), and (2) robust estimation of the unknown aerodynamic torque component required to estimate the EWS. The Lyapunov stability condition and proof for the PMIO are derived and the TSDOFC stability with H∞ performance and D-stability constraints is formulated via a further Linear Matrix Inequality (LMI) problem. The strategy is illustrated using a non-linear benchmark system model of a wind turbine offered within a competition led by the companies Mathworks (USA) and KK-Electronic (Denmark).

Fault tolerant adaptive sliding mode controller for wind turbine power maximisation

This paper presents a new approach to robust fault tolerant control (FTC) to optimise the wind energy captured by a wind turbine in the low wind speed range of operation, using Sliding Mode Control (SMC). In addition to the inherent robustness of SMC against matched model parameter uncertainty, the proposed method can first tolerate generator speed sensor faults and generator torque bias faults. Secondly, the need for a state observer can be removed by using the SMC robustness property and by adapting its switching gain so that the unmeasurable signals are compensated. The sliding surface is designed to achieve the required objectives by utilizing the nonlinear equation of the flexible two mass model of variable speed wind turbine. The proposed FTC SMC method is applied to a 4.8MW wind turbine benchmark model and the results are compared with equivalent results obtained from a “standard controller” (SC).

Sensorless induction motor drive for electric vehicle application

In this paper, an electric vehicle drive with a robust and low cost alternating current (AC) induction motor is presented. This approach is applied to an existing commercial utility electric vehicle where previously used direct current (DC) series motor was replaced by the new AC induction motor. The use of three-phase squirrel cage induction motor requires implementing of voltage source inverter supplied by DC voltage from vehicle battery system. A new DSP based voltage inverter is designed for the proposed drive. The used processor realizes the field oriented control algorithm with torque and flux closed loop control. The proposed drive does not require speed sensor, which make the solution and reliable on speed sensor faults. Motor speed is computed by the processor using speed observer. In this paper system description, control algorithms realization, and speed computation are presented. The paper includes the simulation and experimental results of the discussed system. Keywords: Electric vehicle, induction motor, field oriented control, sensorless control International Journal of Engineering, Science and Technology, Vol. 2, No. 10, 2010, pp. 20-34

Application of Speed and Load Torque Observers in High-Speed Train Drive for Diagnostic Purposes

In this paper, an application of speed and load torque observers is presented. The aim of the observer implementation is to be used in the diagnostic system for a motor speed sensor and a torque transmission system. The diagnostic system is dedicated to the high-speed train propelled by an induction motor. An analysis of the observed variables allows the identification of problems in the mechanical part of the main traction drive. For example, in the case of speed sensor faults, the motor control system could be switched into speed-sensorless control. The proposed observers were verified by simulation and on a test bench for 1.2-MW rail vehicle motor used in high-speed trains.