Control solutions for multiphase permanent magnet synchronous machine drives applied to electric vehicles

207 p.En esta tesis se estudia la utilización de un accionamiento eléctrico basado en una máquina simétrica dual trifásica aplicada al sistema de propulsión de un vehículo eléctrico. Dicho accionamiento está basado en una máquina síncrona de imanes permanentes interiores. Además, dispone de un bus CC con una configuración en cascada. Por otra parte, se incorpora un convertidor CC/CC entre el módulo de baterías y el inversor de seis fases para proveer el vehículo con capacidades de carga rápida, y evitando al mismo tiempo la utilización de semiconductores de potencia con altas tensiones nominales. En este escenario, el algoritmo de control debe hacer frente a las no linealidades de la máquina, proporcionando un comando de consigna preciso para todo el rango de par y velocidad del convertidor. Por lo tanto, deben tenerse en cuenta los efectos de acoplamiento cruzado entre los devanados, y la tensión de los condensadores de enlace en cascada debe controlarse y equilibrarse activamente. En vista de ello, los autores proponen un novedoso enfoque de control que proporciona todas estas funcionalidades. La propuesta se ha validado experimentalmente en un prototipo a escala real de accionamiento eléctrico de 70 kW, probado en un laboratorio y en un vehículo eléctrico en condiciones reales de conducción.Tecnali

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

Novel Thermal Management Strategy for Improved Inverter Reliability in Electric Vehicles

Requirements for electric vehicle (EV) propulsion systems—i.e., power density, switching frequency and cost—are becoming more stringent, while high reliability also needs to be ensured to maximize a vehicle’s life-cycle. Thus, the incorporation of a thermal management strategy is convenient, as most power inverter failure mechanisms are related to excessive semiconductor junction temperatures. This paper proposes a novel thermal management strategy which smartly varies the switching frequency to keep the semiconductors’ junction temperatures low enough and consequently extend the EV life-cycle. Thanks to the proposal, the drivetrain can operate safely at maximum attainable performance limits. The proposal is validated through simulation in an advanced digital platform, considering a 75-kW in-wheel Interior Permanent Magnet Synchronous Machine (IPMSM) drive fed by an automotive Silicon Carbide (SiC) power converter.This work has been supported in part by the European Commission through ECSEL Joint Undertaking (JU) under Grant Agreement No. 783174 (HiPERFORM project), by the Government of the Basque Country within the research program ELKARTEK as the projects ELPIVE (KK-2019/0006) and ENSOL 2 (KK-2020/00077), by the Government of the Basque Country within the fund for research groups of the Basque University system IT978-16, by the Government of Spain through the Agencia Estatal de Investigación Project DPI2017-85404-P, and by the Generalitat de Catalunya through the Project 2017 SGR 872

전기자동차 주행거리 증대를 위한 통합열관리시스템에 관한 연구

학위논문 (박사) -- 서울대학교 대학원 : 공과대학 기계항공공학부(멀티스케일 기계설계전공), 2020. 8. 김민수.전기자동차의1회 충전 주행거리는 탑재된 배터리의 전기용량에 의하여 결정된다. 하지만 최근 적용되고 있는 리튬-이온 배터리의 경우 단위 무게당 에너지 밀도의 한계로 인해 전기승용차의 1회 충전 최대 주행거리는 약 350~400 km를 상회한다. 그런데 이러한 최대 주행 가능 거리는 외기온도에 의해 크게 변동되며 운전자로 하여금 심각한 거리불안감을 유발하고 있으며 이는 전기자동차의 보급 확대에 큰 걸림돌로 알려져 있다. 외기온도에 따라 주행거리가 변화하는 가장 큰 원인은 차량의 실내 열관리를 위해 냉난방 공조시스템에서 요구하는 전기에너지가 클 뿐만 아니라, 이러한 에너지의 양이 외기온도에 따라 큰 폭으로 변화하기 때문이다. 본 연구는 승용전기자동차의 전동 파워트레인과 공조시스템간의 열 적 연계성을 강화시켜 외기온도에 따라 공조시스템 소모 동력 변화가 적은 통합열관리시스템을 제안하였으며, 이러한 통합열관리 시스템이 전기자동차의 주행거리 연장에 미치는 영향성을 정량적으로 분석하였다. 먼저, 시뮬레이션 기반으로 전기자동차의 전동 파워트레인 (배터리,모터,인버터)에서 발생하는 발열량 예측 방법을 제시하였다. 배터리, 모터, 인버터는 전기에너지와 기계에너지간의 연속적인 변환과정을 수행한다. 이러한 변환과정에서 전기에너지는 전압과 전류의 형태로 기계에너지로 변환되며 반대로 발생된 기계에너지는 그것의 역 과정을 통해 배터리로 저장되게 된다. 본 연구에서는 각 구성요소에서 발생하는 발열량을 정량적으로 예측하기 위해 기계에너지와 전기에너지의 실시간 변환에 대한 통합 동력전달모델 및 열에너지 손실 모델을 개발하였다. 실외 온도에 따라 차량의 실내에서 요구되는 공조 부하를 정량적으로 예측하기 위해 열 쾌적성 기반의 차량 실내 모델을 개발하였다. 개발된 모델에서는 차량의 외부로부터 유입되는 복사에너지 뿐만 아니라 차량 내장재의 비열까지 고려하여 보다 현실성이 높은 공조 부하량을 예측할 수 있다. 배터리, 인버터, 모터에서 발생하는 발열량과 공조부하량을 바탕으로 승용전기자동차에 적합한 통합열관리시스템을 설계하였다. 설계된 시스템의 성능과 효율을 검증하기 위해 실험연구를 수해하였으며 그 결과 기본 시스템과 비교하여 난방조건에서는 약 12%, 그리고 냉방조건에서는 약 5% 의 소모동력 저감율을 확인하였다. 이러한 소모동력 저감율이 전기자동차의 주행거리에 미치는 영향력을 확인하기 위해 전기자동차 주행거리 예측 모델을 개발하였다. 다양한 외기조건에 대해 주행거리 증대효과를 확인한 결과 약 10%의 주행거리 증대 효과가 기대된다. 본 연구에서 제시한 통합열관리시스템이 전기자동차에 적용된다면, 외기온도에 따른 주행거리 변화율을 줄이고 나아가 전기자동차 보급에 기여할 수 있을 것으로 기대된다.The mileage of a single charge of an electric vehicle is determined by the capacity of the mounted battery. However, due to the limitation of energy density per unit weight of lithium-ion batteries that have been applied recently, the maximum mileage of an electric passenger car is less than about 500 km. However, this mileage is greatly changed by the outside temperature, causing the driver anxiety, which is known as a major obstacle to the expansion of electric vehicles. The main cause of the change in the driving distance according to the outside temperature is that the air conditioning load used for indoor heat management of the vehicle is large and also varies according to the outside temperature. In this study, we proposed an integrated heat management system with a low rate of change in power consumption of the air conditioning system according to the outside temperature, and quantitatively analyzed the effect of these systems on the mileage extension of electric vehicles. First, a method for predicting the amount of heat generated from a battery, a motor, and an inverter of an electric vehicle was presented based on simulation. The battery, the motor, and the inverter each continuously store and convert electrical energy. In this process, electrical energy moves in the form of voltage and current. In this study, an integrated power transmission model for real-time conversion of mechanical and electrical energy was developed to quantitatively measure the amount of heat generated by each component. In order to quantitatively calculate the air conditioning load required in the interior of the vehicle according to the outdoor temperature, a vehicle interior model based on thermal comfort was developed. In the developed model, it is possible to predict a more realistic air conditioning load by considering not only radiant energy introduced from the outside of the vehicle, but also specific heat of the vehicle interior material. We designed an integrated heat management system that can be applied based on the amount of heat generated from the battery, inverter, and motor and the air conditioning load. Experimental studies were conducted to verify the performance and efficiency of the designed system, and as a result, a reduction in power consumption of about 12% under heating conditions and about 5% under cooling conditions was confirmed. An electric vehicle mileage prediction model was developed to confirm the impact of such reduction in power consumption on the mileage of an electric vehicle. As a result of confirming the effect of increasing the mileage for various outdoor conditions, an effect of increasing the mileage of about 10% is expected. If the integrated heat management system proposed in this study is applied to electric vehicles, it is expected that the mileage change rate according to the outside temperature can be reduced and further contribute to the supply of electric vehicles.Chapter 1. Introduction 1 1.1 Background of the study 1 1.2 Literature survey 8 1.2.1 Electric powertrain thermal management stystem 8 1.2.2 Cabin thermal management system 12 1.2.3 Integrated thermal management system 12 1.3 Objectives and scopes 16 Chapter 2. Electric vehicle thermal load analysis 19 2.1 Introduction 19 2.2 Design a light-duty battery electric vehicle 20 2.2.1 Design an energy storage system 23 2.2.2 Design an electric machine 30 2.2.3 Design a cabin 35 2.3 Electric powertrain thermal load 35 2.3.1 Numerical model description 35 2.3.2 Vehicle dynamics 36 2.3.3 Power electronics and electric machine model 38 2.3.3.1 Electric machine thermal model 38 2.3.3.2 Power electronics thermal model 52 2.3.4 Lithium-ion batterty thermal model 59 2.3.5 Regenerative braking system model 61 2.3.6 Integrated power transfer and loss model 64 2.4 Cabin model thermal load 67 2.4.1 Numerical model description 67 2.5 Results and discussion 75 2.5.1 Electric powertrain thermal load anlysis 75 2.5.2 Cabin thermal load analysis 81 2.5.3 Thermal load imbalance in a light duty electric vehicle 91 Chapter 3. Design and performance analysis of the integrated electric vehicle thermal management system 97 3.1 Introduction 97 3.2 System description 100 3.2.1 Baseline thermal management system 100 3.2.2 A new integrated electric vehicle thermal management system 103 3.3 Numerical analysis of HVAC system 108 3.3.1 Heat exchangers 108 3.3.2 Compressor 113 3.3.3 Expansion device 114 3.3.4 Cycle modeling and simulation condition 116 3.3.5 Heating and cooling capacity prediction 118 3.3.6 Heating and cooling capacity prediction 118 3.4 Experimental study for integrated electric vhicle thermal management system 121 3.4.1 Experimental set up 121 3.4.2 Data reduction and uncertainty analysis 132 3.4.3 Baseline heat pump system 134 3.4.4 A new intergrated electric vehicle thermal management system 141 3.5 Results and discussion 144 3.6 Summary 146 Chapter 4. The effect of the IEVTMS on range extension 149 4.1 Introduction 149 4.2 The effect of IEVTMS for range extension 152 4.3 Range extension opportunities for various ambient temperature 156 4.4 Summary 158 Chapter 5. Concluding remarks 159 Abstract (in Korean) 176Docto

Mathematical Approaches to Modeling, Optimally Designing, and Controlling Electric Machine

Optimal performance of the electric machine/drive system is mandatory to improve the energy consumption and reliability. To achieve this goal, mathematical models of the electric machine/drive system are necessary. Hence, this motivated the editors to instigate the Special Issue “Mathematical Approaches to Modeling, Optimally Designing, and Controlling Electric Machine”, aiming to collect novel publications that push the state-of-the art towards optimal performance for the electric machine/drive system. Seventeen papers have been published in this Special Issue. The published papers focus on several aspects of the electric machine/drive system with respect to the mathematical modelling. Novel optimization methods, control approaches, and comparative analysis for electric drive system based on various electric machines were discussed in the published papers

Multi-Criteria Performance Evaluation and Control in Power and Energy Systems

The role of intuition and human preferences are often overlooked in autonomous control of power and energy systems. However, the growing operational diversity of many systems such as microgrids, electric/hybrid-electric vehicles and maritime vessels has created a need for more flexible control and optimization methods. In order to develop such flexible control methods, the role of human decision makers and their desired performance metrics must be studied in power and energy systems. This dissertation investigates the concept of multi-criteria decision making as a gateway to integrate human decision makers and their opinions into complex mathematical control laws. There are two major steps this research takes to algorithmically integrate human preferences into control environments: MetaMetric (MM) performance benchmark: considering the interrelations of mathematical and psychological convergence, and the potential conflict of opinion between the control designer and end-user, a novel holistic performance benchmark, denoted as MM, is developed to evaluate control performance in real-time. MM uses sensor measurements and implicit human opinions to construct a unique criterion that benchmarks the system\u27s performance characteristics. MM decision support system (DSS): the concept of MM is incorporated into multi-objective evolutionary optimization algorithms as their DSS. The DSS\u27s role is to guide and sort the optimization decisions such that they reflect the best outcome desired by the human decision-maker and mathematical considerations. A diverse set of case studies including a ship power system, a terrestrial power system, and a vehicular traction system are used to validate the approaches proposed in this work. Additionally, the MM DSS is designed in a modular way such that it is not specific to any underlying evolutionary optimization algorithm

Modeling And Analysis Of Multi–Phase Permanent Magnet Synchronous Machines: Direct–Drive Electric Vehicle Application

In commercially existing electric vehicles (EVs), power is transferred from the motor to the wheels through a fixed gear mechanical transmission system. However, such a transmission system contributes to a power loss between 2% to 20% of output power of the motor depending on the operating speed and torque of the motor. Therefore, by removing the transmission, a direct–drive EV configuration is obtained with lower component count, improved motor to wheel efficiency and frequency dependent losses. However, challenges in developing a single on–board permanent magnet synchronous machine (PMSM) for such a configuration include high torque density, low torque ripple and high torque per permanent magnet (PM) volume. Therefore, this dissertation proposes a novel PMSM addressing the aforementioned challenges for a direct–drive application. Initially, the design targets, stator and rotor configuration and phase numbers of the PMSM are chosen to satisfy the requirements of a direct drive application. A novel torque and torque ripple model based on multiple reference frames is proposed, in which the torque ripple from spatial harmonics of flux, inductances and the time harmonics of stator currents are included. Using the analytical model, optimal slot–pole combination of the machine is selected based on adaptive gradient descent algorithm. A new consequent pole rotor topology is proposed to improve the torque density and torque per PM volume thereby reducing the usage of expensive rare earth magnets. The proposed PMSM with novel rotor is further improved in terms of torque density, losses and cost by performing an intensive structural optimization based on novel hybrid analytical model, finite element analysis and supervised learning. The optimized PMSM is then analyzed for various drive cycles and performance in terms of torque, speed and efficiency are discussed. A scaled–down prototype of the proposed PMSM is developed and comprehensive experimental analysis in terms of torque ripple, torque–speed characteristics and efficiency are performed under different speeds and load conditions and are compared with the results obtained from proposed analytical model

Dual Benefits of Adding Damper Bars in PMSMs for Electrified Vehicles: Improved Machine Dynamics and Simplified Integrated Charging

Recently, due to rising environmental concerns and predicted future shortages of fossil fuels, there is a movement towards electrification of the transportation industry. A vast majority of the current research uses permanent magnet synchronous machines as the main traction motor in the drivetrain. This work proposes to add a special damper to a conventional permanent magnet synchronous machine to further improve the suitability of this machine for electrified vehicles. Firstly, an equivalent circuit model is developed to simulate the operation of a conventional PMSM with a damper. A synchronous loading test is proposed to determine the synchronous reactance of the machine. A modified blocked rotor test is used to find the damper parameters assuming that the rotor cage construction is known. Also a single-phase AC test that can be used to determine the damper parameters without prior knowledge of the rotor construction is proposed and presented as an alternative to the blocked rotor test. Thereafter, the models of a 50 kW traction motor and the same machine with damper bars are developed and simulated. The performance of both machines are compared and evaluated. The damper parameters are selected based on the dynamic and steady state performances. It is also shown that the machine with a damper has faster response to a three-phase short circuit fault. In addition, this study also looks into integrated charging which utilizes the existing drivetrain components for vehicle to grid and grid to vehicle operation. The damper is shown to be effective in mitigating the saliency condition caused by the buried magnets of IPMSM at stand-still condition. As a result, the machine windings can be used as line inductors for integrated charging

INVESTIGATION OF PERMANENT MAGNET SYNCHRONOUS MACHINES FOR DIRECT-DRIVE AND INTEGRATED CHARGING APPLICATIONS IN ELECTRIC VEHICLES

Electrified vehicles have proven to be potential candidates in the future for disrupting the automotive industry which is dominated by conventional gasoline vehicles. Electric vehicle (EV) technology has evolved rapidly over the last decade with new designs of EV drivetrain systems and components but no specific design has been able to serve as a solution that is affordable, reliable and performance-wise similar to existing gasoline vehicle equivalent. Extended driving range and overall cost of the vehicle still remain major bottlenecks. Understanding the state-of-the-art technologies and challenges in existing electric vehicle powertrain and charging systems, with major focus on permanent magnet synchronous machines & drives, this dissertation presents the following

Modelling and vector control of dual three‐phase PMSM with one‐phase open

This study proposes a generic mathematical modelling and decoupling fault-tolerant vector control for dual three-phase permanent magnet synchronous machine (PMSM) with one phase open based on the conventional dual three-phase voltage source inverters, accounting for the mutual coupling between two sets of three-phase windings and the second harmonic inductance. When the dual three-phase PMSM has one phase open, the permanent flux-linkages are asymmetric and there are second harmonic components in the conventional synchronous reference frame (dq-frame). Based on the proposed mathematical modelling, both permanent magnet flux-linkages and currents become DC values in the dq-frame, and therefore, the conventional proportional integral (PI) controller can be used to regulate the dq-axis currents. Then, a decoupling fault-tolerant vector control with/without a dedicated feed-forward compensation is proposed to validate the correctness of the proposed mathematical modelling. Experimental results on a prototype dual three-phase PMSM with one phase open show that the second harmonic dq-axis currents can be well suppressed simply by the conventional PI controller and dedicated feed-forward compensation. It also shows that the decoupling fault-tolerant control based on the proposed modelling and control method has excellent dynamic performance, which is equivalent to the vector space decomposition control for the healthy machine