This thesis carries out two basic studies for the flux function and the global observability of IPMSMs, leading to, respectively, two lightweight sensorless algorithms. First, we show that the flux function almost always gives a one-to-one correspondence between the rotor angle and flux, implying that the familiar IPMSM flux equations admit a unique position solution. This result eliminates the need for the arctan/atan2 function, leading to a simple flux estimation-based algorithm. Second, we show that the pair (speed, position) of IPMSMs is not globally observable, and the number of all indistinguishable pairs is at most four, an invariant independent of motor parameters and coincides with the number of the solutions of the two fundamental IPMSM equations. This result, which caps the worst-case scenario sensorless IPMSMs can behave, follows as a corollary by characterizing the observability condition involving infinitely many equations as a special limited form of the injectivity nature of finitely many polynomials. This bigger problem is approached through algebraic methodologies. The FOC scheme causes the “collapse” of at most two indistinguishable pairs and joins forces with the knowledge of motor/generator mode to turn the sensorless task “observable”, leading to another simple algorithm. / Thesis / Doctor of Philosophy (PhD)

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A stator turn fault in a safety-critical drive application must be detected at its initial stage and imperatively requires an evasive action to prevent a serious accident caused by an abrupt interruption in the drive s operation. However, this is much challenging for the case of an interior permanent magnet synchronous motor (IPMSM) drives because of the presence of the permanent magnets that cannot be turned off at will. This work tackles the problem of increase the stator turn fault tolerance of IPMSM drives in safety-critical applications. This objective is achieved by an on-line turn fault detection method and a simple turn fault-tolerant operating strategy. In this work, it is shown that a stator turn fault in a current-controlled voltage source inverter-driven machine leads to a reduced fundamental positive sequence component of the voltage references as compared to the machine without a turn fault for a given torque reference and rotating speed. Based on this finding, a voltage reference-based turn fault detection method is proposed. In addition, it is also revealed that an adjustment to the level of the rotating magnetic flux in an appropriate manner can yield a significant reduction in the propagation speed of the fault and possibly prevention of the fault from spreading to the entire winding. This would be accomplished without any hardware modification. Based on this principle, a stator turn fault-tolerant operating strategy for IPMSM drives maintaining drive s availability is proposed. To evaluate these turn fault detection method and fault-tolerant operating strategy, an electrical model and a thermal model of an IPMSM with stator turn faults are derived. All the proposed models and methods are validated through simulations and experiments on a 10kW IPMSM drive.

This thesis presents a comprehensive study of Direct Torque Control (DTC) for Interior Permanent Magnet Synchronous Motors (IPMSMs) evaluating its potential in high performance motor drive systems. The research begins with a literature review, looking into the fundamental principles of DTC, Pulse Width Modulation (PWM), Space Vector Modulation (SVM) and Field Oriented Control (FOC). The methodology section involves the detailed modeling of IPMSM using Simulink for a precise representation of system dynamics. The Park and Clarke transformations are employed in the phase transformation of currents and voltages to simplify the control strategy. The implementation of Voltage Source Inverter (VSI) is explored and its crucial role in modulating input signals is discussed. Subsequently, the implementation of DTC is demonstrated, capturing the key focus of the thesis. The validation stage verifies the model created in Simulink against research papers published in the same field. This is coupled with an analysis of sector selection and switching table in enhancing DTC performance. The results and conclusion reassess the voltage and flux vectors, evaluating their influence on the system. Additionally, the effectiveness of Proportional-Integral (PI) control for maintaining the desired speed and torque is analyzed. Thus, this thesis offers a holistic perspective on the implementation and performance of DTC for IPMSMs, contributing to the existing body of knowledge and paving the way for future research in this field.

Sans capteur,estimation de la position/vitesse,injection d'un signal HF,apprentissage,MSAPI,VE, / In EV traction applications, most of the mentioned criteria are inescapable, in particularthose related with cost (real-time implementation, additional hardware, etc.), those relatedwith functional requirements (torque ripple, motor efficiency, etc.) not to mention thatsensorless operation must cover the complete speed range.

Permanent magnet synchronous machine drives are used more often. Although, synchronous machines drive also suffer from possible faults. This thesis is focused on the detection of the three-phase synchronous motor winding faults and the detection of the drive control loop sensors' faults. Firstly, a model of the faulty winding of the motor is presented. Effects of the inter-turn short fault were analyzed. The model was experimentally verified by fault emulation on the test bench with an industrial synchronous motor. Inter-turn short fault detection algorithms are summarized. Three existing conventional winding fault methods based on signal processing of the stator voltage and stator current residuals were verified. Three new winding fault detection methods were developed by the author. These methods use a modified motor model and the extended Kalman filter state estimator. Practical implementation of the algorithms on a microcontroller is described and experimental results show the performance of the presented algorithms in different scenarios on test bench measurements. Highly related motor control loop sensors fault detection algorithms are also described. These algorithms are complementary to winding fault algorithms. The decision mechanism integrates outputs of sensor and winding fault detection algorithms and provides an overall drive fault diagnosis concept.