Thank you for reading vector control and dynamics of ac drives. As you may know, people have search hundreds times for their favorite books like this vector control and dynamics of ac drives, but end up in infectious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some infectious bugs inside their computer. vector control and dynamics of ac drives is available in our digital library an online access to it is set as public so you can get it instantly. Our book servers saves in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the vector control and dynamics of ac drives is universally compatible with any devices to read.

Vector Control And Dynamics Of Ac Drives

In the advancement of the semiconductor device technology, ZnO could be a prospective alternative than the other metal oxides for its versatility and huge applications in different aspects. In this review, a thorough overview on ZnO for the application of resistive switching memory (RRAM) devices has been conducted. Various efforts that have been made to investigate and modulate the switching characteristics of ZnO-based switching memory devices are discussed. The use of ZnO layer in different structure, the different types of filament formation, and the different types of switching including complementary switching are reported. By considering the huge interest of transparent devices, this review gives the concrete overview of the present status and prospects of transparent RRAM devices based on ZnO. ZnO-based RRAM can be used for flexible memory devices, which is also covered here. Another challenge in ZnO-based RRAM is that the realization of ultra-thin and low power devices. Nevertheless, ZnO not only offers decent memory properties but also has a unique potential to be used as multifunctional nonvolatile memory devices. The impact of electrode materials, metal doping, stack structures, transparency, and flexibility on resistive switching properties and switching parameters of ZnO-based resistive switching memory devices are briefly compared. This review also covers the different nanostructured-based emerging resistive switching memory devices for low power scalable devices. It may give a valuable insight on developing ZnO-based RRAM and also should encourage researchers to overcome the challenges.

/pdf/status-and-prospects-of-zno-based-resistive-switching-memory-6hnx73qokk.pdf

Status and Prospects of ZnO-Based Resistive Switching Memory Devices

A system-level design optimization method under the framework of a deterministic approach was presented for electrical drive systems in our previous work, in which not only motors but also the integrated control schemes were designed and optimized to achieve good steady and dynamic performances. However, there are many unavoidable uncertainties (noise factors) in the industrial manufacturing process, such as material characteristics and manufacturing precision. These will result in big fluctuations for the product's reliability and quality in mass production, which are not investigated in the deterministic approach. Therefore, a robust approach based on the technique of design for six sigma is presented for the system-level design optimization of drive systems to improve the reliability and quality of products in batch production in this work. Meanwhile, two system-level optimization frameworks are presented for the proposed method, namely, single-level (only at the system level) and multilevel frameworks. Finally, a drive system is investigated as an example, and detailed results are presented and discussed. It can be found that the reliability and quality levels of the investigated drive system have been greatly increased by using the proposed robust approach.

System-Level Design Optimization Method for Electrical Drive Systems—Robust Approach

The rotor overtemperature caused by losses is one of the important issues for the high-speed electric machine. This paper focuses on the loss analysis and thermal performance evaluation for a rotor of 100 kW, 32 km/min high-speed permanent-magnet motor. The rotor temperature distribution based on the finite element method is obtained by accounting for various losses, including air-friction loss of the rotor, iron loss of the active magnetic bearing, and eddy-current loss of the motor. The influence of the stator core temperature on rotor thermal performance is analyzed by using a coupling simulation of fluid-temperature field. The temperature rise measurement of rotor is employed to study the impact of different cooling way on rotor thermal performance and to verify the computational accuracy of losses and temperature distribution. The analysis result of air-friction loss is compared with the measurement, which is obtained from the total losses by using the method of loss separation. It has great significance for the cooling structure design and the efficiency enhancement of electrical machine.

Loss Calculation and Thermal Analysis of Rotors Supported by Active Magnetic Bearings for High-Speed Permanent-Magnet Electrical Machines

In this paper, a multimode design method is proposed for motor design under multiple operation conditions. Based on the driving cycles in electric vehicles, five typical operation conditions and the corresponding five driving modes are determined for the multimode design. To investigate the method conveniently, a flux controllable stator permanent magnet (SPM) memory motor is selected and taken as a design example. In the design process, by using the sensitivity analysis method, the significance of the parameters in various driving modes are evaluated effectively. Based on the motor driving demands, the whole optimization design is divided into three steps, where different optimization method is applied in each step. To verify the feasibility of the multimode design method, the operation performances of the motor in different driving modes are investigated in detail. Finally, a prototype motor is built and tested. Both the simulation and experimental results reveal that the proposed design method can offer an effective design optimization for the flux-controllable SPM memory motor, where multimode operations are indispensable.

Multimode Optimization Design Methodology for a Flux-Controllable Stator Permanent Magnet Memory Motor Considering Driving Cycles

An improved practical two-dimensional model for the analytical calculation of the magnetic field distributions in permanent magnet (PM) eddy current couplings is presented to obtain the torque characteristics. By establishing the Cartesian coordinate reference system on the rotating conductor, the PM region is treated as a source of traveling wave magnetic field and then the multi-layer boundary value problem is solved. The formulation for the magnet blocks, the eddy current and saturation effects in the solid secondary back iron, and the equivalence relationships between typical PM shapes, are all reasonably taken into account. Calculation results produced by the proposed analytical model are compared with those from the nonlinear finite element method and experimental measurement.

A General Analytical Model of Permanent Magnet Eddy Current Couplings

Core-loss prediction is an important issue in design and analysis of permanent-magnet (PM) motors. Because of the diverse structure, flux distribution, and rotational variation of flux, it is difficult to predict the core loss in a machine exactly. In this paper, a core-loss model for the PM motor is introduced in which flux variation loci in different parts of the motor are predicted by carrying out a finite-element transient analysis. Since the flux variation pattern is complicated, an improved equation based on the conventional three-term expression is used for core-loss calculation. The core-loss model is developed totally in ANSYS parametric design language as a parametric model and it can be used easily for different types of PM motors. Calculation and experiments on a high-speed PM motor have shown that the model can produce results that agree with the experimental ones.

Core Loss Modeling for Permanent-Magnet Motor Based on Flux Variation Locus and Finite-Element Method

Compared with the conventional fixed speed drive, a major factor that handicaps the wide acceptance of variable speed drive with high efficiency permanent magnet (PM) motors is its high cost. This paper presents an effort to reduce the material and manufacturing costs of PM motors by using the soft magnetic composite (SMC), and the highly matured powder metallurgic technology. Because the SMC's magnetic properties are quite different from that of the traditional silicon steel sheets, special efforts have been made on measurement and modelling of vectorial magnetic properties, electrical machine topologies, and drive schemes in order to make the best use of the material. Various PM SMC motors of transverse flux topologies have been designed, fabricated, and tested. The detailed results are presented and discussed.

Development of PM Transverse Flux Motors With Soft Magnetic Composite Cores

This paper investigates the losses of a high-speed permanent magnet motor. The iron losses are calculated by a model that can consider the skin effect and rotational loss. The rotor eddy current losses are estimated by a fast hybrid method that can consider the end effect. Pulse-width modulation (PWM) harmonics brought by the voltage source inverter (VSI) are considered in the loss calculations. Then the temperature distribution of the motor is evaluated by using the calculated loss results and computational fluid dynamic (CFD) modeling. Finally, based on the CFD results, the motor structure is optimized to achieve better rotor cooling. The outer slots are closed to force the cooling air flow through the rotor surface. Calculated temperature distributions and optimization results are verified by measurements.

Thermal Optimization of a High-Speed Permanent Magnet Motor

Wind power generation has increased rapidly in China over the last decade. In this paper the authors present an extensive survey on the status and development of wind power generation in China. The wind resource distributions in China are presented and assessed, and the 10 GW-scale wind power generation bases are introduced in details. The domestic research status of main components of WP system is then elaborated, followed by an evaluation of the wind power equipment manufacturers. Finally, the outlook for the development of the wind power utilization in China is presented.

Yunkai Huang

Papers

A General Analytical Model of Permanent Magnet Eddy Current Couplings

Core Loss Modeling for Permanent-Magnet Motor Based on Flux Variation Locus and Finite-Element Method

Development of PM Transverse Flux Motors With Soft Magnetic Composite Cores

Thermal Optimization of a High-Speed Permanent Magnet Motor

Overview of wind power generation in China: Status and development