Advanced deep flux weakening operation control strategies for IPMSM

This paper proposes an advanced flux-weakening control method to enlarge the speed range of interior permanent magnet synchronous motor (IPMSM). In the deep flux weakening (FW) region, the flux linkage decreases as the motor speed increases, increasing instability. Classic control methods will be unstable when operating in this area when changing load torque or reference speed is required. The paper proposes a hybrid control method to eliminate instability caused by voltage limit violation and improve the reference velocity-tracking efficiency when combining two classic control methods. Besides, the effective zone of IPMSM in the FW is analyzed and applied to enhance stability and efficiency following reference velocity. Simulation results demonstrate the strength and effectiveness of the proposed method

Performance Analysis Of IPMSM Drive Using Fuzzy Logic Controller Based Loss Minimization Algorithm (LMA)

This project presents an online loss-minimization algorithm (LMA) for a fuzzy-logic-controller (FLC)-based interior permanent-magnet synchronous-motor (IPMSM) drive to yield high efficiency and high dynamic performance over a wide speed range. LMA is developed based on the motor model. In order to minimize the controllable electrical losses of the motor and thereby maximize the operating efficiency, the d-axis armature current is controlled optimally according to the operating speed and load conditions. For vector-control purpose, FLC is used as a speed controller, which enables the utilization of the reluctance torque to achieve high dynamic performance as well as to operate the motor over a wide speed range. In order to test the performance of the proposed drive in real time, the complete drive is experimentally implemented using DSP board DS1104 for a prototype laboratory 5-hp motor. The performance of the proposed loss-minimization-based FLC for IPMSM drive is tested in both simulation and experiment at different operating conditions. A performance comparison of the drive with and without the proposed LMA-based FLC is also provided. It is found from the results that the proposed LMA and FLC-based drive demonstrates higher efficiency and better dynamic responses over FLC-based IPMSM drive without LMA. In this project, an online LMA-based speed-control scheme of IPMSM drive incorporating an FLC has been presented. The LMA was developed based on the motor model

Nonlinear adaptive control for robust wide speed range operation of IPMSM drives

Various applications, including robotics, spindle drives, machine tools, etc. rely on accurate, reliable controllers to deliver the required drive performance. With recent advances in magnetic materials and semiconductor technology, machines such as the permanent magnet synchronous machine (PMSM) family of ac drives have seen a rise in popularity, owing to the high power density, efficiency and relative longevity as compared to conventional ac motors. In particular, interior permanent magnet synchronous machines (IPMSM) are characterized by all the features of the PMSM family, with the additional possibility of improved efficiency due to rotor construction, making them ideal for critical applications with high performance demands. Notably, despite the advantageous aspects of PMSM motors in general, control of this class of ac machines is complex if full performance potential is to be realized. In order to achieve optimal efficiency while permitting wide speed range operation, it is crucial to design controllers that are capable of delivering this high performance. Due to the nonlinearity of magnetic flux distribution during operation, the parameters of the PMSM may vary significantly. Thus, a high performance controller must be capable of optimizing efficiency while maintaining excellent response characteristics from set-point or loading variations. As a result of the nonlinear flux distribution caused by rotor/stator magnetic field interactions, direct control of PMSM in the stator reference frame is not possible as the level of mathematical complexity renders it infeasible. Expression of the PMSM stator variables in the rotating rotor reference frame permits the effective decoupling of machine variables into velocity and torque control components. This is roughly analogous to separately excited direct current (DC) motors, where control of the rotor speed (field magnetization) and shaft torque (armature current) are decoupled as a function of the design. Analysis of the PMSM model in the rotating reference frame shows that the “d” and “q” axis currents are principally responsible for indirect air gap flux control and developed shaft torque, respectively. Traditional linear type control techniques based on proportional-integral-derivative (PID) controllers are able to achieve moderate success in controlling the PMSM family. The performance achieved is however typically within a narrow operational band and without the ability to adapt to parametric variation or optimize efficiency. This restriction makes PID type controllers non-ideal for more demanding applications that require highly accurate control and high efficiency regardless of load, temperature, machine age or operating environment. Therefore, this thesis presents a robust nonlinear control algorithm utilizing an adaptive back-stepping technique with flux control for optimizing developed torque and improved operational range. Further, global asymptotic stability of the proposed controller is assured through Lyapunov’s stability criterion in conjuncture with criterion supported by Barbalat’s lemma. The proposed control algorithm ensures that the machine operates at precise command speeds, coping with system uncertainties and disturbances, while reducing losses and enabling operation over a wide speed range. Simulation of the proposed system is carried out in MATLAB/Simulink, as well as in a cosimulation environment utilizing MATLAB/Simulink and PSIM. The first scenario implements an ideal mathematical system model with the controller in Simulink; whereas the second scenario uses PSIM to host the dynamic system model, with MATLAB/Simulink hosting the controller. This co-simulation permits rapid, accurate system analysis, by employing more accurate software models for switching elements, synchronous machine and any reactive elements not reflected in the basic mathematical model. Simulation results from both methods indicate excellent performance and robust operation, with excellent disturbance rejection. Real-time implementation of the system is realized utilizing the DS1104 digital signal processor (DSP) in conjuncture with an IPMSM commutated by a three-phase two-level insulated gate bipolar transistor (IGBT) inverter, with a direct current (DC) generator as dynamic load. Performance of the proposed controller have been verified through experimental implementation for a range of operating conditions

Performance analysis of interior permanent magnet synchronous motor (IPMSM) drive system using different speed controllers

The present research is indicating that the Permanent magnet motor drive could become serious competitor to the induction motor drive for servo application. Further, with the evolution of permanent magnet materials and control technology, the Permanent Magnet Synchronous Motor (PMSM) has become a pronounced choice for low and mid power applications such as computer peripheral equipments, robotics, adjustable speed drives and electric vehicles due to its special features like high power density, high torque/inertia ratio, high operating efficiency, variable speed operation, reliability, and low cost etc. Here we deals with the detailed modeling of an IPMSM drive system with Hybrid PI-Fuzzy logic controller (PI-FLC) as speed controller and Adaptive Hysteresis Current Controller as torque controller by controlling the current components of torque.In this thesis we deals with a simulation for speed control and improvement in the performance of a closed loop vector controlled IPMSM drive which employ two loops for better speed tracking and fast dynamic response during transient as well as steady state conditions by controlling the torque component of current. The outer loop employ Hybrid PIFuzzy logic controller (PI-FLC) while inner loop as Adaptive Hysteresis Band Current Controller (AHBCC) designed to reduce the torque ripple. Despite proportional plus Integral (PI) controller are usually preferred as speed controller due to its fixed gain (Kp) and Integral time constant (Ki), the performance of PI controller are affected by parameters variations, speed change and load disturbances in PMSM, due to which it results to unsatisfied operation under transient conditions. The drawbacks of PI controller are minimized using fuzzy logic controller (FLC). So for this a fuzzy control technique is also designed using mamdani type, triangular based 5x5 MFs and selecting the superior functionalities of PI and FLC, a Hybrid PI-FLC designed for effective speed control under transient and steady state condition.The complete viability of above mentioned integrated control strategy is implemented and tested in the MATLAB/Simulink environment and a performance comparison of proposed drive system with conventional PI, fuzzy logic controller and Hybrid PI-Fuzzy Logic Controller integrated separately as speed controller in terms of steady state and transient analysis with fixed step, variable step load and variable speed condition has been presented. Beside this a detailed comparative study of AHBCC is also done with Conventional Hysteresis Current Control(CHCC) scheme. The simulation circuits parameters for IPMSM, inverter, speed and current controllers of the drive system are given in Appendix-A

Field weakening and sensorless control solutions for synchronous machines applied to electric vehicles.

184 p.La polución es uno de los mayores problemas en los países industrializados. Por ello, la electrificación del transporte por carretera está en pleno auge, favoreciendo la investigación y el desarrollo industrial. El desarrollo de sistemas de propulsión eficientes, fiables, compactos y económicos juega un papel fundamental para la introducción del vehículo eléctrico en el mercado.Las máquinas síncronas de imanes permanentes son, a día de hoy la tecnología más empleada en vehículos eléctricos e híbridos por sus características. Sin embargo, al depender del uso de tierras raras, se están investigando alternativas a este tipo de máquina, tales como las máquinas de reluctancia síncrona asistidas por imanes. Para este tipo de máquinas síncronas es necesario desarrollar estrategias de control eficientes y robustas. Las desviaciones de parámetros son comunes en estas máquinas debido a la saturación magnética y a otra serie de factores, tales como tolerancias de fabricación, dependencias en función de la temperatura de operación o envejecimiento. Las técnicas de control convencionales, especialmente las estrategias de debilitamiento de campo dependen, en general, del conocimiento previo de dichos parámetros. Si no son lo suficientemente robustos, pueden producir problemas de control en las regiones de debilitamiento de campo y debilitamiento de campo profundo. En este sentido, esta tesis presenta dos nuevas estrategias de control de debilitamiento de campo híbridas basadas en LUTs y reguladores VCT.Por otro lado, otro requisito indispensable para la industria de la automoción es la detección de faltas y la tolerancia a fallos. En este sentido, se presenta una nueva estrategia de control sensorless basada en una estructura PLL/HFI híbrida que permite al vehículo continuar operando de forma pseudo-óptima ante roturas en el sensor de posición y velocidad de la máquina eléctrica. En esta tesis, ambas propuestas se validan experimentalmente en un sistema de propulsión real para vehículo eléctrico que cuenta con una máquina de reluctancia síncrona asistidas por imanes de 51 kW

Development and Implementation of Novel Intelligent Motor Control for Performance Enhancement of PMSM Drive in Electrified Vehicle Application

The demand for electrified vehicles has grown significantly over the last decade causing a shift in the automotive industry from traditional gasoline vehicles to electric vehicles (EVs). With the growing evolution of EVs, high power density, and high efficiency of electric powertrains (e–drive) are of the utmost need to achieve an extended driving range. However, achieving an extended driving range with enhanced e-drive performance is still a bottleneck. The control algorithm of e–drive plays a vital role in its performance and reliability over time. Artificial intelligence (AI) and machine learning (ML) based intelligent control methods have proven their continued success in fault determination and analysis of motor–drive systems. Considering the potential of intelligent control, this thesis investigates the legacy space vector modulation (SVM) strategy for wide–bandgap (WBG) inverter and conventional current PI controller for permanent magnet synchronous motor (PMSM) control to reduce the switching loss, computation time and enhance transient performance in the available state–of–the-art e–drive systems. The thesis converges on AI– and ML–based control for e–drives to enhance the performance by focusing in reducing switching loss using ANN–based modulation technique for GaN–based inverter and improving transient performance of PMSM by incorporating ML–based parameter independent controller

Fuzzy logic based efficiency optimization of IPM synchronous motor drive

Interior permanent magnet synchronous motor (IPMSM) is highly appreciated by researchers in variable speed drive applications due to some of its advantageous features such as small size, high power density, simple maintenance, high output torque, high power factor, low noise and robustness as compared to the conventional IM and other ac motors. Although these motor drives are well known for their relatively high efficiency, improvement margins still exist in their operating efficiency. Particularly, the reduction of power loss for IPMSM still remains a challenge for researchers. Improvement of motor drives efficiency is important not only from the viewpoints of energy loss and hence cost saving, but also from the perspective of environmental pollution. The thesis presents development of a fuzzy logic based efficiency and speed control system of an IPMSM drive. In order to maximize the efficiency in steady state operation while meeting the speed and load torque demands a search based fuzzy efficiency controller is designed to minimize the drive power losses to achieve higher efficiency by reducing the flux. The air gap flux level can be reduced by controlling the d-axis armature current as it is supplied by rotor permanent magnet. In order for the drive to track the reference speed in transient operation another fuzzy logic based controller is designed to increase the flux depending on the speed error and its derivative. The torque component of stator current (q-axis component of stator current) is generated by fuzzy logic based speed controller for different dynamic operation depending on speed error and its derivative. In this work a torque compensation algorithm is also introduced to reduce the torque and speed fluctuations

Efficiency Optimised Control of Interior Permanent Magnet Machine Drives in Electric Vehicle Applications

The thesis focuses on the losses minimisation of an interior permanent magnet synchronous machine (IPMSM) drive in electric vehicle applications. As drive losses are a combination of the IPMSM losses and the inverter losses, this thesis is mainly divided into two parts: the first part deals with minimising the copper and iron losses of the IPMSM with due account of machine parameters variations and the voltage drop across the stator winding resistance. A new losses minimisation algorithm (LMA) which considers these issues is presented in this research. A comprehensive off-line simulation study based on this LMA is performed in order to evaluate the effect of the parameters variations, resistive voltage drop and iron losses on the IPMSM optimal efficiency operation. It is shown that the parameters variations and resistive voltage drop should be included in the losses minimisation to achieve IPMSM optimal efficiency operation. On the other hand, the minimum losses operation points are not significantly affected by the utilised IPMSM iron losses. The proposed LMA is implemented with non-linear look-up tables (LUTs) using the current commands developed for both constant torque and field weakening operations. Good matching between the simulation and experimental results has been achieved. Reducing the inverter switching losses is the aim of the second part of this PhD research in addition to decrease the common mode voltage (CMV) which may lead to undesirable motor bearing current and electromagnetic interference. A comparative study between up-to-date PWM techniques for CMV reduction with the conventional space vector PWM (SVPWM technique) through simulation studies are presented. Due to its advantages on reducing both the switching losses and CMV of the inverter over all (αβ) voltage hexagon modulation regions, the LuPWM technique is selected for the tested IPMSM drive. Firstly, the scalar implementation of this LuPWM technique using the sine triangle waveform modulation technique on a simulation model of a resistor-inductor (R-L) inductive load is validated with sinusoidal current waveforms. However, implementation of the LuPWM in the closed loop control system of the tested IPMSM drive results in a considerable unexpected distortion in the phase current waveforms especially at low demanded torques. A study on this issue shows that due to the unavoidable ripples on the electrical angle position information leading to the malfunction on determining the (αβ) voltage hexagon sectors, the sector transition point of the LuPWM pulses especially when the state of the LuPWM pulse is changed between On-state and Off-state is strongly affected. Consequently, the current waveforms for a closed-loop drive system under the LuPWM technique during the sectors transition period become seriously distorted. In this thesis, the LuPWM current waveforms distortion problem is proposed to be addressed by modifying the pulse pattern of the traditional LuPWM technique around the (αβ) voltage hexagon sectors transition points associated with significant current waveforms distortion as aforementioned. Under this proposed PWM technique denoted as Mod-LuPWM technique, the switching state of each LuPWM pulse is suggested to be hold for an optimum small period around each transition period. Hence, the adverse effects of the angular ripple and the voltage error will be evened out between the “Turn-On” and “Turn-Off” transitions. Therefore, sinusoidal current waveforms can be obtained for closed-loop drive system under the proposed Mod-LuPWM. In addition, similar to the traditional LuPWM the Mod-LuPWM technique own the ability of on reducing the peak-to-peak common mode voltage value to one sixth of the DC-link voltage compared with the traditional PWMs. On the other hand, due to its switching characteristics, the switching losses of the drive system under the Mod-LuPWM technique are also reduced by one third during the switching period leading to an increase on the switching device life-time. Furthermore, as its implementation does not require any additional hardware, the proposed Mod-LuPWM can be employed for any existing drive system without any increase in the total drive cost. The proposed Mod-LuPWM has been validated with well-matched between simulation and experimental results showing significant current waveform improvements and considerable CMV reduction

Advances in Rotating Electric Machines

It is difficult to imagine a modern society without rotating electric machines. Their use has been increasing not only in the traditional fields of application but also in more contemporary fields, including renewable energy conversion systems, electric aircraft, aerospace, electric vehicles, unmanned propulsion systems, robotics, etc. This has contributed to advances in the materials, design methodologies, modeling tools, and manufacturing processes of current electric machines, which are characterized by high compactness, low weight, high power density, high torque density, and high reliability. On the other hand, the growing use of electric machines and drives in more critical applications has pushed forward the research in the area of condition monitoring and fault tolerance, leading to the development of more reliable diagnostic techniques and more fault-tolerant machines. This book presents and disseminates the most recent advances related to the theory, design, modeling, application, control, and condition monitoring of all types of rotating electric machines

Sensorless control for limp-home mode of EV applications

PhD ThesisOver the past decade research into electric vehicles’ (EVs) safety, reliability and availability has become a hot topic and has attracted a lot of attention in the literature. Inevitably these key areas require further study and improvement. One of the challenges EVs face is speed/position sensor failure due to vibration and harsh environments. Wires connecting the sensor to the motor controller have a high likelihood of breakage. Loss of signals from the speed/position sensor will bring the EV to halt mode. Speed sensor failure at a busy roundabout or on a high speed motorway can have serious consequences and put the lives of drivers and passengers in great danger. This thesis aims to tackle the aforementioned issues by proposing several novel sensorless schemes based on Model Reference Adaptive Systems (MRAS) suitable for limp-home mode of EV applications. The estimated speed from these schemes is used for the rotor flux position estimation. The estimated rotor flux position is employed for sensorless torque-controlled drive (TCD) based on indirect rotor field oriented control (IRFOC). The capabilities of the proposed schemes have been evaluated and compared to the conventional back-Electromotive Force MRAS (back-EMF MRAS) scheme using simulation environment and a test bench setup. The new schemes have also been tested on electric golf buggies. The results presented for the proposed schemes show that utilising these schemes provide a reliable and smooth sensorless operation during vehicle test-drive starting from standstill and over a wide range of speeds, including the field weakening region. Employing these new schemes for sensorless TCD in limp-home mode of EV applications increases safety, reliability and availability of EVs