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A detailed analysis has been conducted on two motor control algorithms: direct torque control (DTC) and field-oriented control (FOC). There are two ways that a voltage source inverter (VSI) can regulate a permanent magnet synchronous motor (PMSM). When using the PMSM and voltage source inverter (VSI), dead time is employed to turn off both the upper and lower switches to prevent short circuits. However, by supplying the PMSM with unexpected polarity voltages at the VSI output voltage, this switching technique reduces distortion. It is challenging to utilize the sensor to directly detect the fault voltage that results in an open circuit. This work examines the nonlinearity of the electric power controller during dead time during PMSM operation using the DTC algorithm to increase control stability. The stress distribution is estimated using an extended Kalman filter (EKF). Ultimately, the model presented in this study verified the increase in stator current and torque output through simulations and testing. [ABSTRACT FROM AUTHOR]

The direct torque control (DTC) of permanent magnet synchronous motor (PMSM), which includes flux and torque double closed-loops, requires constant flux and high calculation accuracy. Besides, uncertain flux estimation will cause torque ripples. To solve these problems, in this paper, twelve-sector direct torque control (DTC) without flux closed-loop for PMSM is proposed. To reduce the requirement on constant flux and high calculation accuracy and to simplify the structure of the system, the flux closed-loop is removed from the control system. To suppress the torque ripple, a twelve-sector space voltage vector control scheme is adopted which increases the switch states of the inverter. The number of nonzero voltage vectors is increased from 6 to 12 without increasing the hardware equipment of the system. The sections of the voltage vectors are redefined and the torque ripples are reduced. The hardware-in-the-loop simulation results show the effectiveness and feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

The main aim of this paper is to present a novel control approach of an induction machine (IM) using an improved space vector modulation based direct torque control (SVM-DTC) on the basis of imaginary swapping instant technique. The improved control strategy is presented to surmount the drawbacks of the classical direct torque control (DTC) and to enhance the dynamic performance of the induction motor. This method requires neither angle identification nor sector determination; the imaginary swapping instant vector is used to fix the effective period in which the power is transferred to the IM. Both the classical DTC method and the suggested adaptive DTC techniques have been carried out in MATLAB/SimulinkTM. Simulation results shows the effectiveness of the enhanced control strategy and demonstrate that torque and flux ripples are massively diminished compared to the conventional DTC (CDTC) which gives a better performance. Finally, the system will also be tested for its robustness against variations in the IM parameters. [ABSTRACT FROM AUTHOR]

Direct Torque Control (DTC), a superior technique, which controls the stator flux and electromagnetic torque of an electrical machine. In spite of its numerous advantages, it possesses certain shortcomings like torque ripples, flux ripples, variable switching frequency and problems during the startup conditions. Recently, Matrix Converters (MC) have emerged as an efficient alternate for the Voltage Source Inverter employed in the DTC technique, which is capable of providing flexible and dynamic control over the torque and flux ripples associated in a machine. In this paper, a review on different control techniques associated in implementing the Matrix Converters for DTC method are categorized as follows: Subdivision of MC Voltage Vector method, SVM (Space Vector Modulation) based MC-DTC method, MC-DTC Duty Cycle Control, Employing Rotational Vectors of MC and Model Predictive Torque Control method. The pros and cons of each matrix converter fed direct torque control methods are presented by analyzing the experimental results from the literature. [ABSTRACT FROM AUTHOR]

The direct torque control (DTC) of permanent magnet synchronous motor (PMSM) drives is a noticeable practice in industrial applications due to its quick dynamic performance. However, due to the presence of hysteresis controllers and inaccurate switching tables especially for the multilevel fed DTC drives are facing higher ripples in torque and flux response. An improved DTC for three‐level open‐end winding PMSM drive is proposed in this article and features reduction of flux and torque ripples. The torque and flux performances of the PMSM are directly controlled by the calculated reference voltage vector in the stationary reference frame. The voltage vector tables are proposed based on the length of the voltage space vectors and the actual voltage vector nearer to the calculated reference voltage vector is selected so that the minimum ripples exist in flux and torque responses. The steady‐state and dynamic conditions of the proposed DTC method are verified in the real‐time experiment and also compared with the conventional DTC as well as the recently developed control methods. [ABSTRACT FROM AUTHOR]

The electrical drive systems utilized in Electric Vehicles (EVs) applications must be reliable and high performance. To providing these specifications, it is essential to design high-efficiency electric motors and develop high-performance controllers. This study introduces direct torque control of Switched Reluctance Motor (SRM) for electric vehicle applications using Model Predictive Control (MPC) technique. The direct torque control using MPC is proposed to maintain the motor torque and motor speed to tracking desired signals with a satisfactory response. In this study, the MPC algorithm was programmed in C- language, and the simulation tests were performed using a non-linear model of 6/4 - 60 kW SRM that is fed with the symmetrical converter. The proposed controller was tested under different load conditions to verify the robustness of the controller, as well as at variable speeds to investigate the tracking performance. Thanks to the proposed method, the SRM torque ripples, stator copper losses, and average switching frequency of the power converter can reduce effectively due to applying a cost function that combines multiple objectives. The obtained outcomes show the effectiveness of the suggested approach compared to conventional direct torque control techniques. [ABSTRACT FROM AUTHOR]

Because of the current commutation and the double-salient pole structure of single-winding bearingless switched reluctance motors (SWBSRMs), the torque and radial forces have large ripples when present control methods are used. In order to solve those problems, a novel solution is proposed in this paper, which can achieve direct torque control (DTC) and direct force control (DFC) simultaneously. With the hysteresis-loop control of torque and flux linkage, the power switches of converter can be directly controlled based on the proposed space voltage vectors. First, the basic space voltage vectors are transformed correspondingly to realize DTC for BSRMs. After that, considering the generation principle of levitation forces, the basic space voltage vectors are transformed into equivalent space voltage vectors to facilitate the implementation of DFC. As a result, the torque and levitation forces can be controlled at the same time only with the developed equivalent space voltage vectors. The complicated current control algorithm is not needed, which is necessary for conventional methods. Moreover, the levitation performance is improved with the proposed method. Experimental results show that the torque ripple and radial displacements of SWBSRMs can be reduced approximately by 80% and 29%, respectively. [ABSTRACT FROM AUTHOR]

A robust field-weakening method for direct-torque-controlled (DTC) synchronous reluctance motors is presented in this paper. The proposed algorithm achieves smooth transition between the constant torque and field-weakening regions. Maximum torque per ampere is utilized below base speed, while both the current and voltage limits of the drive system are satisfied in the field-weakening region. The proposed method is robust to the variations in the machine dq -axis inductances. This ensures the system stability during field-weakening operation, especially along the maximum torque per flux trajectory. The proposed algorithm is incorporated into the duty ratio regulation-based DTC to achieve high-performance torque and flux control in the field-weakening region. Experimental results included in this paper confirm the veracity of the proposed method. [ABSTRACT FROM AUTHOR]

The conventional direct torque control (DTC) features control structure simplicity, fast dynamic response, and parameter robustness. Nevertheless, it suffers from the problems of variable switching frequency and large torque ripples. This paper presents a modified DTC algorithm for interior permanent magnet synchronous motor drives with fast torque dynamics and constant switching frequency. The aforementioned problems are alleviated by adding a PI torque regulator to autonomously alter the effective duty cycle of the applied voltage vector. As a result, a constant switching frequency and also reduced torque ripples are obtained while retaining the benefits of the classical DTC. In addition, the torque dynamic response is further improved by introducing a modified switching table during transient conditions. By incorporating the modified switching table, the torque dynamic response is superior to that of the classical DTC. Simulation and experiment results included confirm the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper presents a robust field weakening method for the direct torque controlled (DTC) synchronous reluctance motors (RSMs). The proposed method ensures a smooth and stable transition between the maximum torque per ampere and field weakening including the maximum torque per flux regions. In addition, it is also robust to the variation in the machine dq-axes inductances in the field weakening region. The proposed algorithm is amalgamated with a duty ratio regulation based DTC to achieve high performance torque and flux control in the field weakening region. The effectiveness of the RSM drive is verified by both simulations and experiments. [ABSTRACT FROM PUBLISHER]

The active vector effects on torque and stator flux linkage are different in direct torque control (DTC) system. These differences may cause the over‐compensation or under‐compensation to torque and flux linkage leading to large ripples. Aimed at making sure the system can work in an optimum state, a novel duty ratio modulation strategy minimising the torque and flux linkage ripples is designed. Every sector is divided into five small sectors, and a new switching table is designed. The impact factors and the active factors are first introduced into the DTC system. Subsequently, a novel duty ratio modulation method is derived. The superiority is verified through the simulation results. [ABSTRACT FROM AUTHOR]

This paper proposes a new passive filter topology to reduce torque ripples and harmonic noises in interior permanent magnet synchronous motor (IPMSM) derived by hysteresis direct control. The filter topology consists of compound dissipative filter cascaded by RLC low pass filter. The compound filter has two tuning frequency setting points, one at inverter switching frequency and the other at some average selected frequency. The filter topology is characterized by affecting inverter switching frequency in a way that decreases stress on switching elements including dv/dt. The filter topology uses series dissipative elements to reshape motor voltage waveform to provide semi-sinusoidal voltage to the motor windings. The simulation results show that the proposed topology effectively reduces torque ripples as well as total harmonic distortion (THD) and electro-magnetic interference (EMI) noise level. [ABSTRACT FROM AUTHOR]

This paper describes an active filter topology to improve the performance of hysteresis direct torque control (HDTC) of interior permanent magnet synchronous motor (IPMSM). The filter topology consists of an active filter and two RLC filters, and is connected to the main power circuit through a 1:1 transformer. The active filter is characterized by detecting the harmonics in the motor phase voltages and injecting equivalent harmonic voltages to produce almost sinusoidal voltage waveform to the motor terminals. The active filter uses hysteresis voltage controller while the motor main circuit uses hysteresis direct torque control. The simulation results of this combined control structure show considerable torque ripple reduction in the steady state range and adequate dynamic torque performance as well as considerable harmonic voltage and EMI noise reduction. [ABSTRACT FROM AUTHOR]