A new deadbeat type of direct torque control is proposed, analyzed and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods.

Stator and Rotor Flux Based Deadbeat Direct Torque Control of Induction Machines. Revision 1

To reduce the dependence on oil and environmental pollution, the development of electric vehicles has been accelerated in many countries. The implementation of EVs, especially battery electric vehicles, is considered a solution to the energy crisis and environmental issues. This paper provides a comprehensive review of the technical development of EVs and emerging technologies for their future application. Key technologies regarding batteries, charging technology, electric motors and control, and charging infrastructure of EVs are summarized. This paper also highlights the technical challenges and emerging technologies for the improvement of efficiency, reliability, and safety of EVs in the coming stages as another contribution.

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Technology development of electric vehicles: A review

The permanent magnet synchronous generator (PMSG) is dominantly used in the present wind energy market. Reflecting the latest wind energy market trends and research articles, this study presents a survey on important electrical engineering aspects for PMSG-based megawatt-level wind energy conversion systems (WECSs). A comprehensive analysis on power converter topologies for wind turbines (WTs), grid integration of wind farms, digital control schemes, fault-ride-through compliance methods, and future trends is presented. The updated market share, technology trends, WT products information, in-depth technical analysis, and promising research works highlighted in this study will help the reader to understand the state-of-the-art and emerging technologies for PMSG-based WECS.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-epa.2016.0799

PMSG-based wind energy conversion systems: survey on power converters and controls

To reduce the steady-state torque ripples for permanent-magnet synchronous motor drives with predictive torque control (PTC), this paper proposes a modified PTC algorithm based on the extended control set (ECS-PTC). In the proposed algorithm, more candidate voltage vectors are extended to the control set, which forms the ECS, and then, the torque control precision could be improved and the torque ripples will be reduced. More attractive thing is that a new voltage vector synthesis method is deigned in ECS-PTC, and the corresponding predictive model and cascaded predictive algorithm are set up on the basis of this method. With the help of them, the optimal vector can be selected from ECS in a shorter control period of time, and its amplitude is also optimized at the same time to achieve high-precision control effects for torque and flux. In addition, the three-phase duty ratios of the output vector can be determined in ECS-PTC directly, without the help of space vector pulse width modulation. The experimental results show that ECS-PTC has excellent dynamic torque performance, and it also has more stable torque control performance and better execution efficiency at the same time.

Torque Ripple Minimization of Predictive Torque Control for PMSM With Extended Control Set

This paper reviews the modern electric propulsion architectures and configurations for railway traction, which are currently in practice. The development and advancement of power electronics and digital controllers led to the standardization of the insulated gate bipolar transistor (IGBT)-based converter fed induction motor drives. This paper summarizes the state-of-the-art technology of IGBT-based rolling stock in terms of both power and control. Control hierarchy of traction system and drive control techniques are explored. Special emphasis has been put on the technologies, which can improve energy efficiency as well as reliability to develop high-speed rails and metro trains in the near future in both urban and suburban areas. Specific attention is given to power electronic transformer technology-based traction drives and on-board energy storage systems. In addition, advances in traction drive technology and wide-bandgap power devices are addressed. Finally, major issues faced in rolling stock including the challenges for further improvement are highlighted.

Comprehensive Topological Overview of Rolling Stock Architectures and Recent Trends in Electric Railway Traction Systems

This paper presents a comprehensive evaluation of several direct torque control (DTC) strategies for permanent magnet synchronous machines (PMSMs), namely DTC, model predictive DTC, and duty ratio modulated DTC. Moreover, field-oriented control is also included in this study. The aforementioned control strategies are reviewed and their control performances are analyzed and compared. The comparison is carried out through simulation, finite-element analysis, and experimental results of a PMSM fed by a two-level voltage source inverter. With the intent to fully reveal the advantages and disadvantages of each control strategy, critical evaluation has been conducted on the basis of several criteria: Torque ripple, stator flux ripple, switching frequency of inverter, steady-state control performance, dynamic response, machine losses, parameter sensitivity, algorithm complexity, and stator current total harmonic distortion.

Comparative Evaluation of Direct Torque Control Strategies for Permanent Magnet Synchronous Machines

This paper proposes a novel duty ratio modulated direct torque control (DDTC) to concurrently reduce torque ripple and stator flux ripple that are typically associated with conventional direct torque control (DTC). Three different methods of duty ratio determination are presented to achieve various control objectives, namely DDTC-final, DDTC-mean and DDTC-rms. Additionally, adjustable error weight coefficients are introduced to balance the torque ripple reduction and stator flux ripple reduction. Experimental results are presented to validate the effectiveness of proposed DDTC. Furthermore, the comparative evaluation of proposed DDTC, conventional DDTC and DTC is conducted on the basis of several criteria to verify the superiority of proposed DDTC.

Direct Torque Control for Permanent-Magnet Synchronous Machines Based on Duty Ratio Modulation

This paper presents a detailed comparative evaluation of several direct torque control (DTC) strategies for permanent magnet synchronous machines (PMSMs), namely basic DTC, model predictive DTC (MPDTC) and DTC with duty ratio modulation (DTC-duty). Moreover, field orient control (FOC) is also included in this study. The aforementioned control strategies are reviewed and their performances are analyzed and compared. The comparison is carried out through simulation of a 60 kW PMSM fed by a two-level voltage source inverter (VSI). With the intent to fully reveal advantages and disadvantages of each control strategy, critical evaluation has been conducted on the basis of several criteria: torque and stator flux ripple, inverter switching frequency, machine parameter sensitivity, computational complexity and stator current total harmonic distortion (THD). The choice of control scheme can be determined based on specific requirements of particular application under consideration.

Comparative evaluation of direct torque control strategies for permanent magnet synchronous machines

This paper proposes a simple and practical duty cycle modulated direct torque control (DDTC) for permanent magnet synchronous motors. The duty cycle of active vector is obtained using a duty cycle generator according to the torque error and motor speed, which can avoid the complex calculation process associated with conventional DDTC. The design details about the duty cycle generator are illustrated, and the stability of the proposed DDTC is analyzed, which ensures the reliable operation of the motor system. Experimental results are presented to validate the effectiveness of the proposed DDTC. Furthermore, the comparative evaluation of the proposed DDTC and conventional DDTC is conducted to verify the superiority of the proposed DDTC.

A Simple and Practical Duty Cycle Modulated Direct Torque Control for Permanent Magnet Synchronous Motors

Permanent magnet synchronous machines work with controllers and controller parameters affect the machine's voltages and currents and, thus, the diagnosis of stator winding fault. One such parameter is the current controller bandwidth that affects the harmonic content in these signals. In the literature, the second harmonics in both $dq$ -axis currents and voltages have been used for fault detection, and the main advantage is that interturn short-circuit (ITSC) winding fault with a few shorted turns, specially one turn, can be detected. One indicator that combines the fault information in voltages and currents is the instantaneous reactive power (IRP). However, it has been shown that IRP does not perform robustly with respect to current controller bandwidth. The main contribution of this article is that it proposes and validates a new mathematical function for ITSCs detection, Rayleigh quotient, which combines the fault information present in voltages and currents to make ITSCs detection robust to current controller bandwidth. The validations from both cosimulation and experiment show that the proposed method is robust to the bandwidth and can detect ITSC faults faster than IRP.

Kui Li

Papers

Comparative Evaluation of Direct Torque Control Strategies for Permanent Magnet Synchronous Machines

Direct Torque Control for Permanent-Magnet Synchronous Machines Based on Duty Ratio Modulation

Comparative evaluation of direct torque control strategies for permanent magnet synchronous machines

A Simple and Practical Duty Cycle Modulated Direct Torque Control for Permanent Magnet Synchronous Motors

Robust Stator Winding Fault Detection in PMSMs With Respect to Current Controller Bandwidth