Moez Abassi

Performance analysis of FOC and DTC for PMSM drives using SVPWM technique

The aim of this article is to present the performance of field oriented control (FOC) and direct torque control (DTC) of a permanent magnet synchronous motor (PMSM) using the technique of space vector pulse width modulation (SVPWM). First, after developing a mathematical model of PMSM we present the principle of space vector modulation technique to use in commands. Secondly, we developed a field oriented control and direct torque control strategy. Finally, we proposed a failover system between direct torque control and field oriented control in the event of default or loss of information.

A sliding-mode observer for high-performance sensorless control of PMSM with initial rotor position detection

ABSTRACTThis paper proposes a new method to detect the initial rotor position at standstill of permanent magnet synchronous motor (PMSM). To estimate rotor position and rotor speed from the back electromotive force (EMF) voltage, we apply sensorless speed control based on sliding-mode observer (SMO). The initial rotor position is detected by using a suitable high-frequency sequence of voltage pulses intermittently applied to the stator windings at standstill. With this approach, we managed to minimise the error on the estimated position to 3.75° electrical degrees without additional materials and uncomplicated calculations. The stability of the proposed SMO was verified using the Lyapunov method. Numerical simulations and experiments demonstrate that the novel SMO method can effectively estimate rotor position and speed with achievement of good static and dynamic performance. The experimental implementation is carried out on powerful dSpace DS1103 controller board based on the digital signal processor (DS...

Position sensorless vector control of PMSM drives based on SMO

In this document, an sensorless field oriented control (FOC) for PMSM utilizing the SMO is proposed. We have building a new sliding mode observer to estimate the rotor velocity/position from the back EMF, in which a continuous function (called sigmoid) is applied instead the sign method. The stability verification of our observer was made by the Lyapunov theorem. The effectiveness of sensorless FOC was validated by the results obtained in section 4. The simulation results obtained by using Matlab/Simulink program validate the robustness of the SMO under parameter variations and external disturbance.

Fault tolerant control and reconfiguration for three-phase permanent magnet synchronous motors drive

this paper proposes a fault tolerant control (FTC) for permanent magnet synchronous motors (PMSM) using field-oriented control (FOC) and direct torque control (DTC) strategy. In order to ensure continuity of operation and without losing PMSM performance in fault, the proposed FTC allows transition from FOC to DTC. The FOC of PMSM drive needed a mechanical sensor to measure rotor position but with the second strategy this was not necessary. The simulation results confirm the effectiveness of the FTC method proposed.

A rotor initial position estimation method for sensorless field-oriented control of permanent magnet synchronous motor

In this paper, a new technique to improve initial rotor position detection at standstill of a permanent magnet synchronous motor (PMSM) is presented. Sensorless field-oriented control (FOC) of a PMSM at low speed remains a difficult task. In order to estimate the position and rotor speed, we proposed a novel structure of a full-order sliding mode observer (FO-SMO) in a sensorless FOC. At standstill, we used a voltage pulse sequence applied to the windings in order to detect the initial rotor position. With this technique, we managed to minimize the error on the estimated rotor position to 3.75° (electrical) compared with others. The validity of the proposed approach with a 1.1-kW low-speed PMSM sensorless FOC has been proved by experimental results.

PMSM DTC Drive System Fed by a Fault-Tolerant Inverter

Sensorless control of a permanent magnetsynchronous motor (PMSM) at low speed remains a challenging task. In this paper, a sensorless vector control of PMSM using a new structure of a sliding mode observer (SMO) is proposed. To remove the mechanical sensors, a full‐order (FO‐SMO) is built to estimate the rotor position and speed of PMSM drives. The FO‐SMO, which replaces a sign function by a sigmoid function, can reduce the chattering phenomenon. In order to overcome time delay, we cancel the low pass filter. This sensorless speed control shows great sensitivity to stator resistance and system noise. To improve the robustness of sensorless vector control, a full‐order SMO technique has been used for stator resistance estimation. A novel stator resistance estimator is incorporated into the sensorless drive to compensate for the effects of stator resistance variation. The validity of the proposed FO‐SMO with a 1.1 kw low‐speed PMSM sensorless vector control is demonstrated by experiments. In this paper, experimental results for FO‐SMO, back‐EMF SMO and MRAS techniques were obtained with fixed point DSP‐based (TMS320F240).

Real-time implementation of discrete fourier transform phase analysis and fault tolerant control for PMSM in electric vehicles

Electric vehicles (EVs) require uninterrupted and safe conditions during operations. Therefore, the diagnostic of power devices and electric motor faults are needed to improve the availability of the system. Hence, fault-tolerant control (FTC), which combines switch fault detection, hardware redundancy and post-fault control, is used. This paper aims to propose an accurate open-phase fault detection and FTC of a direct torque control permanent magnet synchronous motor electrical vehicles by using discrete Fourier-transform phase method.,The main idea is to propose detection and identification of open-phase fault (faulty leg) among three phases voltage source invertor (VSI)-fed permanent magnet synchronous motor drives. Once the faulty leg is detected and isolated, a redundant phase leg insertion, shared by a three-phase VSI, is done by using independent bidirectional TRIAC switches to conduct FTC system. This accurate fault detection significantly improves system availability and reliability. The proposed method of open-phase fault detection and identification is based only on stator phase current measurement.,A novel method is proposed with experimental validation for fault detection, isolation and FTC for a three-phase VSI-fed permanent magnet synchronous motor.,The novel discrete Fourier-transform phase method is proposed to detect an open phase based on the measurement in real time of the instantaneous phase of stator current components in the stationary frame. The experimental implementation is carried out on powerful dSpace DS1104 controller board based on the digital signal processor TMS320F240. The validity of the proposed method has been experimentally verified.

Performance analysis of PMSM DTC drives under inverter fault

This paper presents an investigation of an inverter fault tolerant direct torque control (DTC) of permanent magnet synchronous motor (PMSM) with loss of one leg. In case of faulty inverter, continuous operation is necessary and thus a breakdown of the PMSM drive is unacceptable. The basic idea of this work consists in analyzing performance of a three legs inverter and two legs inverter fed PMSM drive using DTC technique. Simulation results show that the two legs inverter fed PMSM is able to operate steadily under the DTC approach proposed.

Sensorless FOC of PMSM drives based on full order SMO

This document deals with a sensorless field oriented control (FOC) for permanent magnet synchronous motor (PMSM) drives by using a full order sliding mode observer (FOSMO). We have constructed a FO-SMO to estimate the position and velocity. The Lyapunov theorem is used to verify the FO-SMO stability. The experimental findings indicate the robustness of SM observer under parametric variations.