Hew Wooi Ping

Adaptive Fuzzy Sliding-Mode Control Into Chattering-Free IM Drive

This paper presents an adaptive fuzzy sliding-mode controller (AFSMC) based on the boundary layer approach for speed control of an indirect field-oriented control (IFOC) of an induction motor (IM) drive. In general, the boundary layer approach leads to a tradeoff between control performances and chattering elimination. To improve the control performances, a fuzzy system is assigned as reaching control part of the fuzzy sliding-mode so that it eliminates the chattering completely in spite of the large uncertainties in the system. The applied fuzzy controller acts like a saturation function with a nonlinear slope inside thin boundary layer near the sliding surface to guarantee the stability of the system. Moreover, an adaptive law is implemented to estimate the unknown bound of uncertainty, which is obtained in the sense of Lyapunov stability theorem to minimize the control effort. The proposed AFSMC-based IM drive is implemented in real-time using DSP board TI TMS320F28335. The experimental and simulation results show the effectiveness of the proposed AFSMC-based IM drive at different operating conditions.

AXIAL-FLUX PERMANENT-MAGNET MOTOR DESIGN FOR ELECTRIC VEHICLE DIRECT DRIVE USING SIZING EQUATION AND FINITE ELEMENT ANALYSIS

The design process of a double-sided slotted TORUS axial- ∞ux permanent-magnet (AFPM) motor suitable for direct drive of electric vehicle (EV) is presented. It used sizing equation and Finite Element Analysis (FEA). AFPM motor is a high-torque-density motor easily mounted compactly onto a vehicle wheel, fltting the wheel rim perfectly. A preliminary design is a double-sided slotted AFPM motor with 6 rotor poles for high torque-density and stable rotation. In determining the design requirements, a simple vehicle-dynamics model that evaluates vehicle performance through the typical cruising trip of an automobile was considered. To obtain, with the highest possible torque, the initial design parameters of the motor, AFPMs fundamental theory and sizing equation were applied. Vector Field Opera-3D 14.0 commercial software ran the FEA of the motor design, evaluating and enhancing accuracy of the design parameters. Results of the FEA simulation were compared with those obtained from the sizing equation; at no-load condition, the ∞ux density at every part of the motor agreed. The motors design meets all the requirements and limits of EV, and flts the shape and size of a classical-vehicle wheel rim. The design process is comprehensive and can be used for an arbitrary EV with an arbitrary cruising scenario.

Advances on Single-Phase Line-Start High Efficiency Interior Permanent Magnet Motors

The past 25 years have been a significant period with advances in the development of interior permanent magnet (IPM) machines. Line-start small IPM synchronous motors have expanded their presence in the domestic marketplace from few specialized niche markets in high efficiency machine tools, household appliances, small utility motors, and servo drives to mass-produced applications. A closer examination reveals that several different knowledge-based technological advancements and market forces as well as consumer demand for high efficiency requirements have combined, sometimes in fortuitous ways, to accelerate the development of the improved new small energy efficient motors. This paper provides a broad explanation of the various factors that lead to the current state of the art of the single-phase interior permanent motor drive technology. A unified analysis of single-phase IPM motor that permits the determination of the steady-state, dynamic, and transient performances is presented. The mathematical model is based on both d-q axis theory and finite-element analysis. It leads to more accurate numerical results and meets the engineering requirements more satisfactorily than any other methods. Finally, some concluding comments and remarks are provided for efficiency improvement, manufacturing, and future research trends of line-start energy efficient permanent magnet synchronous motors.

Dual Vector Control Strategy for a Three-Stage Hybrid Cascaded Multilevel Inverter

This paper presents a voltage control algorithm for a hybrid multilevel inverter based on a staged-perception of the inverter voltage vector diagram. The algorithm is applied to control a three-stage eighteen-level hybrid inverter, which has been designed with a maximum number of symmetrical levels. The inverter has a two-level main stage built using a conventional six-switch inverter and medium- and low- voltage three-level stages constructed using cascaded H-bridge cells. The distinctive feature of the proposed algorithm is its ability to avoid the undesirable high switching frequency for high- and medium- voltage stages despite the fact that the inverter’s dc sources voltages are selected to maximize the number of levels by state redundancy elimination. The high- and medium- voltage stages switching algorithms have been developed to assure fundamental switching frequency operation of the high voltage stage and not more than few times this frequency for the medium voltage stage. The low voltage stage is controlled using a SVPWM to achieve the reference voltage vector exactly and to set the order of the dominant harmonics. The inverter has been constructed and the control algorithm has been implemented. Test results show that the proposed algorithm achieves the desired features and all of the major hypotheses have been verified.

A Comprehensive Review of Axial-Flux Permanent-Magnet Machines

This paper presents a state-of-the-art review of axial-flux permanent-magnet (AFPM) machines in the aspects of construction, features, electromagnetic and thermal modeling, simulation, analysis, design, materials, and manufacturing. Some key references on the above-mentioned aspects pertaining to the machine are discussed briefly. Particular emphasis is given on the design and performance analysis of AFPM machines. A comparison among different permanent magnet machines is also provided. Thus, this paper makes a bridge between the currently used permanent magnet machines in industry and the recent developments of AFPM machines.

New Three-Phase Multilevel Inverter With Reduced Number of Power Electronic Components

In this paper, a new configuration of a three-phase five-level multilevel voltage-source inverter is introduced. The proposed topology constitutes the conventional three-phase two-level bridge with three bidirectional switches. A multilevel dc link using fixed dc voltage supply and cascaded half-bridge is connected in such a way that the proposed inverter outputs the required output voltage levels. The fundamental frequency staircase modulation technique is easily used to generate the appropriate switching gate signals. For the purpose of increasing the number of voltage levels with fewer number of power electronic components, the structure of the proposed inverter is extended and different methods to determine the magnitudes of utilized dc voltage supplies are suggested. Moreover, the prototype of the suggested configuration is manufactured as the obtained simulation and hardware results ensured the feasibility of the configuration and the compatibility of the modulation technique is accurately noted.

New multilevel inverter topology with minimum number of switches

This paper presents two types of multilevel inverters, known as symmetrical and asymmetrical multilevel inverter. Both types are very effective and efficient for improving the quality of the inverter output voltage. Firstly, we describe briefly the structural parts of the inverter then switching strategy and operational principles of the proposed inverter are explained and operational topologies are given. The proposed topology reduces the number of switches, losses, installation area and converter cost. Finally, the simulation results are provided to validate the proposed theory.

Self-Tuned NFC and Adaptive Torque Hysteresis-Based DTC Scheme for IM Drive

This paper presents a simplified self-tuned Sugeno-type neuro-fuzzy controller (NFC)-based direct torque control (DTC) scheme for induction motor (IM) drive. A simple tuning algorithm is developed based on the reference and actual acceleration of the motor. The online tuning strategy adjusts the parameters of the consequent layer of the NFC in order to minimize the square of the error between the actual and the reference acceleration of the motor. In a conventional DTC scheme, the band limits of flux and torque hysteresis controllers remain fixed, and hence, the torque and flux ripples are high. In order to minimize the torque ripples of the IM, the hysteresis band limits are adjusted online for the torque hysteresis controller. Thus, the proposed NFC is used to achieve high dynamic performance of the drive, and the variable hysteresis controller is used to reduce the steady-state torque ripple. The proposed NFC-based DTC scheme is successfully implemented in real time using the DSP board DS1104 for a prototype 1-hp squirrel-cage IM. The performance of the proposed drive is tested at different operating conditions in both simulation and experiment. The proposed NFC-based DTC scheme is found superior to the conventional DTC scheme in both steady-state and transient conditions.

Improvement to performance of solid-rotor-ringed line-start axial-flux permanent-magnet motor

This paper presents two design-and-analysis cases of a line- start axial-∞ux permanent-magnet motor: with solid rotor and with composite rotor. For a novel structure of the motor, two concentric unilevel spaced raised rings are added to the inner and outer radii of its rotors to enable auto-start capability. The composite rotor was coated by a thin (0.05mm) layer of copper. The basic equations for the solid rotor ring were extracted. The motors lack of symmetry necessitated 3D time-stepping flnite element analysis, conducted via Vector Field Opera 14.0, which evaluated the design parameters and predicted the motors transient performance. Results of the FEA show the composite rotor signiflcantly improving both starting torque and synchronization capability over solid rotor.

Asymmetrical Cascaded Multilevel Inverter Based on Transistor-Clamped H-Bridge Power Cell

This paper presents an asymmetrical cascaded multilevel inverter based on a five-level transistor-clamped H-bridge power cell. A two-cell configuration with a dc link voltage ratio of 4 : 1 is presented. The modulation method is based on the fundamental frequency switching. An analysis of the inverter output voltage and harmonics is presented. Injection of the third harmonic voltage as to maximize the output voltage and the issue of the inverse power flow or regeneration in the low-voltage cell are presented. The prototype of the proposed inverter was built, and its functionality was verified through experimental results.