No abstract

This paper focuses on the universal control design of permanent magnet synchronous motors (PMSMs) with uncertain system dynamics. In vector control, classical proportional-integral (PI) controllers are used to control d-q axis currents and speed of the PMSM. This paper uses two control methods: conventional field-oriented vector control and simplified control. First, all the control gains are determined for numerous PMSMs with various power ratings using an empirical study and generalized mathematical expressions are derived for each of the gains. Then, these expressions are used for automatic gain calculation for various PMSMs with a wide power-rating range. In vector control, the control gains are determined using only the motor power ratings. In the simplified control, generalized control gain expressions are obtained using the number of pole pairs and the flux linkage. Compared to the vector control, the simplified control method provides much simpler generalized mathematical expressions. Validation is carried out in MATLAB/Simulink environment using various PMSMs from 0.2 HP to 10 HP, and results show accurate tracking of reference speed and d-q axis reference currents. Thus, the proposed gain scheduling approach is effective and can be used for self-commissioning motor drives.

No abstract

The use of a direct torque control (DTC) drive is a well-known control strategy that is applied frequently to induction motors. Although torque and stator flux ripples are major disadvantages of this approach, using a higher-level inverter helps to overcome these issues. In this paper, we propose a novel switching table with a modified control strategy for a three-level inverter to achieve ripple minimization, as well as smooth switching and neutral point balance; the latter features are generally ignored in many works. The proposed model is compared with a conventional DTC and an improved three-level inverter-fed voltage vector synthesis model in the Matlab/Simulink® environment with low, normal, and high-speed operation under load torque disturbances. The performance indexes and the comparative results confirm the effectiveness of the proposed model in reducing the torque and stator flux ripples by up to 70% and 78%, respectively, generating a lower total harmonic distortion (THD%) in all scenarios, in addition to maintaining the neutral point balance and preventing voltage jumps across the switches of the inverter.

The permanent magnet synchronous machine is considered one of the signicant electric machines used in dierent applications due to its high torque density, high power density, high eciency, and low maintenance. Due to the PM synchronous machines' design, the control system can drive the motor to deliver high torque to mechanical loads with the lowest current, which is called the maximum torque per ampere (MTPA) control method, and operate the generator to inject maximum electric energy into the grid at any mechanical power, which is called the maximum power extraction (MPE).MTPA control can be achieved by direct voltage control. Therefore, a simple direct voltage MTPA control strategy is suggested with a thorough insight analysis to dene the control gains analytically, which simplies the control ultimately and makes it more suitable for low-cost real-time implementation compared to other methods. The proposed method tracks the MTPA trajectory by nding the optimal pair of voltage angle and amplitude for each motor's speed and torque conditions. This is achieved without the need for any current control loop, which makes the technology simple to a great extent, contrary to most methodologies, but this simplicity is made possible by ignoring transient terms that guarantee MTPA only at steady-state. To overcome this limitation, simple dynamic direct control approaches are proposed to compensate for transient terms, making MTPA operation possible in all operating conditions with/without current sensors. The proposed strategies are applied to an interior permanent magnet synchronous motor (IPMSM) for industrial and electric vehicle applications and a surface-mount permanent magnet synchronous generator (SPMSG) for wind energy conversion system implementations.To illustrate the suggested control methods' capability, comparative studies are conducted against the popular MTPA vector control strategy. Experimental results for various situations reveal the suggested MTPA controllers' ability. Additionally, to quantitatively assess the MTPA trajectory tracking accuracy, the proposed control methods are compared using a qualication metric with energy consumption and energy eciency studies.iii I also like to thank the Department of Electronics and Prof. Chaoui for the nancial support in the form of scholarships and RA nancing.Besides, I would want to thank my family and friends, particularly my parents and daughters, for their unwavering support during my Ph.D. program. I am appreciative of their assistance in bringing this task to successful completion.Last but not least, I would like to thank and dedicate this thesis to my wife, Tasneem, for the love, support, and constant encouragement I have gotten over the years.