M. Boussak

Sensorless Indirect Stator Field Orientation Speed Control for Single-Phase Induction Motor Drive

The industrial requirements for the control of an induction machine without a mechanical sensor continue to be of interest, as evidenced by the most recent publications. The focus is on improvements of control without a mechanical sensor. A new method for the implementation of a sensorless indirect stator-flux-oriented control (ISFOC) of a single-phase induction motor (SPIM) drive is proposed in this paper. The proposed method of rotor speed estimation is based only on the measurement of the main and auxiliary windings stator currents and that of a reference q-axis current generated by the control algorithm. The error of the measured q-axis current from its reference value feeds the proportional plus integral controller, the output of which is the estimated slip angular frequency. Experimental results for sensorless ISFOC speed control of a SPIM drive are presented and analyzed using a dSPACE system with DS1104 controller board based on the digital signal processor TMS320F240. Digital simulation and experimental results are presented to show the improvement in performance of the proposed sensorless algorithm.

Multiple IGBTs open circuit faults diagnosis in voltage source inverter fed induction motor using modified slope method

This paper deals with multiple insulated gate bipolar transistor (IGBTs) open circuit faults detection and localization in a pulse width modulation (PWM) voltage source inverter (VSI) fed induction motor based on a modified slope method. Firstly, a detection algorithm was used to calculate the slope of the current-vector trajectory in complex plan αβ. This algorithm detects the faulty bridge. Second, the Schmitt-trigger is used for the phases currents monitoring. This circuit determines the phases currents polarity and detect whether the current in the faulty arm is positive or negative. The analysis of two combined information makes it possible to diagnose the two simultaneous IGBTs open circuit fault within inverter. The proposed technique is developed and implemented to vector control induction motor drives. An experimental setup in the laboratory is used to compare the simulation results and the experimental results and to evaluate the performances of the proposed method.

Open phase faults detection in PMSM drives based on current signature analysis

This paper deals with monitoring condition of electrical failures in variable speed of permanent magnet synchronous motor (PMSM) drives by stator current signature analysis. The objective of this study is to develop a detection method for the open phase fault in PMSM drives. The main idea consists in minimizing the number of sensors allowing the open stator phase fault of the system to study. The harmonics produced by current spectral analysis fault-related components are studied. The current waveform patterns for various modes of open phase winding are investigated. Simulation and experimental results are presented using a 1.1 kW, 6 poles three-phase PMSM. Comparison of simulation and experimental results show that the method is able to detect the open-phase fault in PMSM drive.

PWM-Switching pattern-based diagnosis scheme for single and multiple open-switch damages in VSI-fed induction motor drives

This paper deals with a fault detection technique for insulated-gate bipolar transistors (IGBTs) open-circuit faults in voltage source inverter (VSI)-fed induction motor drives. The novelty of this idea consists in analyzing the pulse-width modulation (PWM) switching signals and the line-to-line voltage levels during the switching times, under both healthy and faulty operating conditions. The proposed method requires line-to-line voltage measurement, which provides information about switching states and is not affected by the load. The fault diagnosis scheme is achieved using simple hardware and can be included in the existing inverter system without any difficulty. In addition, it allows not only accurate single and multiple faults diagnosis but also minimization of the fault detection time to a maximum of one switching period (T(c)). Simulated and experimental results on a 3-kW squirrel-cage induction motor drive are displayed to validate the feasibility and the effectiveness of the proposed strategy.

An improved diagnosis technique for IGBTs open-circuit fault in PWM-VSI-fed induction motor drive

This paper deals with an improved technique for insulated-gate bipolar transistors (IGBTs) open-circuit fault diagnoses in voltage source inverter (VSI) fed induction motors. The extraction of the fault information is based on the combining of the switching pattern and the electric drive line-to-line voltage measurements. The combined diagnosis signals make possible to detect and identify the single and multiple open-circuit faults of the inverter switches. Furthermore, only one line-to-line voltage is necessary to diagnose two inverter legs simultaneously. For simplicity and cost-effectiveness, the fault detection is carried out by a simple circuit. To avoid the false diagnosis alarms, the time delays due to turn-on and turn-off process of the power switches are compensated while acting on the switching pattern. Different from the conventional method, the proposed technique was marked by a better time delay between the fault occurrence and its detection. The Simulation results are displayed to confirm the proposal.

Development and Experimental Evaluation of a Sensorless Speed Control of SPIM Using Adaptive Sliding Mode-MRAS Strategy

The aim of this paper is to provide a high-performance sensorless control of single phase induction motor drives. The synthesis of second-order sliding mode controllers to drive the rotor speed and the stator currents is based on the adaptive super twisting algorithm. The proposed method for the estimation of speed is based on sliding mode model reference adaptive system (SM-MRAS) observer. Whereas, in order to disturbance and uncertainties cancellation, an adaptive time varying switching gain is designed then adopted. A discrete low pass filter was used to improve the estimator generated signal for practical implementation, representing a very simple design process compared with other chattering reduction methods as adding an observer. The stability of the SM-MRAS speed estimation algorithm is proved using the Lyapunov approach and its robustness is investigated under load conditions. Simulation and experimental results prove the effectiveness of the proposed sensorless speed control algorithm.

FDI based on an adaptive observer for current and speed sensors of PMSM drives

Abstract This paper deals with a new method of current and speed sensors faults detection isolation (FDI) and identification for a permanent magnet synchronous motor (PMSM) drives. A new state variable is introduced so that an augmented system can be constructed to treat PMSM sensor faults as actuator faults. This method uses the PMSM model and a bank of adaptive observers to generate residuals. The residuals results are used for sensor fault detection. A logic algorithm is built in such a way to isolate and identify the faulty sensor for a stator phase current fault after detecting the fault occurrence. Simulation results are presented to illustrate the functionality of theoretical developments. Experimental results with 1.1-kW PMSM have validated the effectiveness of the proposed FDI method. The experimental implementation is carried out on powerful dSpace DS1103 controller board based on the DSP TMS320F240.

Simultaneous estimation of speed and rotor resistance in sensorless ISFOC induction motor drive based on MRAS Scheme

Usually the estimation of speed is achieved by assuming that the rotor resistance is constant throughout the operating range. In practice, the variation of this resistance depends on the temperature inside the machine. This paper proposes a simultaneous rotor speed and rotor resistance estimation method for a conventional indirect stator flux oriented controlled (ISFOC) induction motor drive. In order to estimate the both parameters, an adaptation algorithm based on the model reference adaptive system (MRAS) scheme for tuning the rotor speed and the rotor resistance is proposed. The reference and adjustable models, developed in stationary stator reference frame, are used in the MRAS scheme to estimate rotor speed and rotor resistance from measured terminal voltages and currents. The Integral-Proportional (IP) speed controller and Proportional-Integral (PI) current controller gains are calculated and tuned at each sampling time according to the new simultaneous estimation. A 3-phase induction motor has been used to verify the accuracy and feasibility of the proposed method. Simulation results show that the proposed method gives accurate estimations of simultaneous rotor speed and rotor resistance for a reference speed of the induction motor drive with nominal load torque is applied.

Model Reference Adaptive System Based Adaptive Speed Estimation for Sensorless Vector Control with Initial Rotor Position Estimation for Interior Permanent Magnet Synchronous Motor Drive

Abstract The rotor position/speed sensor used to control the permanent magnet synchronous motor drive has increased size and cost, decreased reliability, and a need for shaft extension and mounting arrangements. Sensorless control is currently adopted in many industrial applications for reasons of robustness, cost, cabling, and reliability. In order to achieve correct operation from zero speed startup of a sensorless salient-pole permanent-magnet synchronous motor (the interior permanent magnet synchronous motor), the initial rotor position of the motor is required. A model reference adaptive system technique has been used for speed estimation in sensorless speed control of the interior permanent magnet synchronous motor with space vector pulse width modulation. This article presents a new approach to improved initial rotor position detection of an interior permanent magnet synchronous motor. The method uses a suitable sequence of short and long time voltage pulses applied to the stator coil at standstill. Short time voltage pulses are applied to the motor terminals to detect the initial rotor position. Long time voltage pulses are used for detection of the magnet polarity based on the effect of saturation. The measurement of the current peaks values gives information about the initial rotor position. Simulation and experimental results are presented and show the validity of the proposed method, which is capable of reliable initial rotor position detection, including the polarity of the magnet at standstill. The error initial rotor position detection is less than 5 mechanical degrees. Experimental results are presented for an interior permanent magnet synchronous motor obtained on a fixed-point digital signal processor based control system. Experimental results show that the modeled reference adaptive system technique speed estimation provides high-performance sensorless control and initial rotor position estimation algorithms of the interior permanent magnet synchronous motor drive.

Robustness and limitations of sensorless technique based on Luenberger state-Observer for induction motor drives under inverter faults

The aim of the present paper is double; the first is to implement a sensorless Indirect Stator Field Oriented Control (ISFOC) of three phase induction motor drive based on the Luenberger Observer (LO). The second is to study the robustness and the limitations of the proposed sensorless vector control technique under abnormal operations of the electric drive. The proposed sensorless strategy is based on an algorithm permitting a better simultaneous estimation of the rotor speed and the flux linkage including an adaptive mechanism based on the lyaponov theory. To study the reliability, the robustness and the limitations of the sensorless technique to abnormal operations, some experimental tests have been performed under several cases: single open switch damage in a leg, multiple faults involving two transistors belonging to the same inverter leg. For healthy and faulty operation mode, an experimental setup based on a 3kW squirrel-cage induction motor has been used.