No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Abstract
The application of direct torque control (DTC) to brushless ac drives has been investigated extensively. This paper describes its application to brushless dc drives, and highlights the essential differences in its implementation, as regards torque estimation and the representation of the inverter voltage space vectors. Simulated and experimental results are presented, and it is shown that, compared with conventional current control, DTC results in reduced torque ripple and a faster dynamic response.
... This is the author's version which has not been fully edited and content may change prior to final publication. Hence the voltage space vector structure of a three-phase BLDC motor drive has different orientation and vector magnitude, compared to the conventional voltage space vector structure of a three-phase inverter fed AC motor drive [29][30]. Figure-1 illustrates the circuit diagram of a 3phase inverter-fed star-connected BLDC motor drive, while Figure-2 depicts its voltage space vector structure. ...
... In Figure 2, the symbols '+' and '-' denote connections to the positive and negative terminals of the DC source, respectively. The symbol 'X' indicates that the corresponding phase winding is not connected to the DC source [29][30]. For example, the triplet '(-+X)' indicates that the A-phase stator winding is connected to the negative rail of the DC bus, the B-phase stator winding is connected to the positive rail of the DC bus, and the C-phase stator winding is disconnected from the DC source. ...
This article presents a new multi-level voltage space vector structure-based control scheme for dual inverter-fed open-end winding BLDC (OEW-BLDC) motor drives, incorporating peak current control. An analysis of the voltage space vector structure of the OEW-BLDC motor drive is carried out first to identify the voltage vectors for developing two distinct PWM schemes tailored for low-speed and high-speed operations of the drive. The proposed scheme reduces the torque ripple in the drive due to the substantial reduction in the magnitude of the error voltage vectors while implementing the PWM scheme. In addition, this scheme ensures that only one inverter is switched at a time and the other inverter is clamped at a particular level, thereby reducing the switching losses. The multilevel voltage space vector structure-based switching also ensures that dv/dt is reduced substantially. The proposed scheme is verified by simulation as well as experiment on a laboratory prototype, employing a TMS320F28377S digital signal controller to implement the control algorithm.
... The hysteresis controllers suffer by several transformations which complicates the control techniques without the improvement in the torque control [14]. Several Direct Torque Control (DTC) topologies have been employed in BLDC motor applying conventional [15,16] and unconventional [17,18] inverter topologies. This DTC strategy is used to control the torque using 2-phase and 3-phase conduction mode. ...
... The duty cycle for the steady state non-commutated phase current can be obtained by equating Equation (15) to zero and can be written as, ...
Brushless Direct Current (BLDC) motors are advantageous because of their higher efficiency, higher speed operations and higher power density. Industrial applications demand BLDC motors free from torque ripple. The torque ripple is due to the unequal commutation period between the energised phase and unenergized phase current. It is a perilous problem in sensorless BLDC drive as it leads to speed oscillations, acoustic noise, serious faults, and vibration in machines. The torque ripple can be reduced either by improving motor design parameter or by improving the motor control strategy. This paper proposes a Proportional Integral (PI) controller-based control scheme for a cuk converter driven sensorless BLDC motor to reduce the torque ripple. The proposed scheme invokes Zero Crossing Point (ZCP) detection with back emf sensing approach. The presence of inductor reduces the ripple in the input and output currents. The performance of the strategy is verified using MATLAB R2018a Simulink for different operating conditions of a BLDC drive and the results prove that the recommended scheme decreases the torque ripple compared to the conventional scheme.
... Since saturation due to armature reaction will lead to changes in flux and inductance, the output torque will also be affected. The overall output torque T e can be considered as being made up of three components: PM excitation torque T PM , reluctance torque T r, and cogging torque T cog and can be expressed by [14][15][16]: ...
... According to the slot/pole number combinations, the CPPM machines can be divided into two groups [14]. Therefore, in this paper, a CPPM machine with an odd slot number for one phase in a submachine, 12-slot/8-pole (12s8p), and a CPPM machine with an even slot number for one phase in a submachine, 12s10p, are selected for demonstration, which is denoted as conventional CPPM (CCPPM) machines, i.e., 12s8p-CCPPM and 12s10p-CCPPM machines. ...
Consequent pole permanent magnet (CPPM) machines can improve the ratio of average torque to PM volume, but suffer from more serious armature reactions. In this paper, the variations of electromagnetic performance of surface-mounted PM (SPM), conventional CPPM machines, and pole-shaped CPPM machines with armature reaction at currents up to 5 times overload are analyzed and compared. The flux densities, flux linkages, back EMFs, inductances, torque characteristics, and demagnetization withstand capabilities are analyzed by the finite element method (FEM) and frozen permeability method. It is validated that the third order harmonics in inductances for CPPM machines tend to be reduced as current rises since the saturation in iron pole is prone to reducing the saliency effect. But the armature reaction tends to result in the increase of torque ripple components for all the machines. It is also found that the overall torque ripple of asymmetric pole-shaped machine tends to increase significantly under overload conditions. On the contrary, the symmetrical pole-shaped machine can maintain a relatively stable torque ripple under overload conditions which is similar to the SPM counterpart. Additionally, due to the large armature reactions, CPPM machines suffer from weaker demagnetization withstand capabilities and weaker overload capabilities than their SPM counterparts. Four CPPM prototypes with and without pole shaping are tested to confirm the FEM analysis.
... We can find in literature a lot of efforts to reduce the torque ripple. [2][3][4][5][6] are only some to name. Le-Huy, Perret and Feuillit [2] analyzed the torque by using Fourier series and shown that the torque ripple can be reduced by appropriately injecting selected current harmonics to eliminate the torque ripple components. ...
... Le-Huy, Perret and Feuillit [2] analyzed the torque by using Fourier series and shown that the torque ripple can be reduced by appropriately injecting selected current harmonics to eliminate the torque ripple components. Yong Liu, Z. Q. Zhu and David Howe [5] utilized DTC to reduce torque ripple in addition to increasing torque dynamics. Haifeng Lu, Lei Zhang and Wenlong Qu [6] calculated duty cycles in the torque controller considering un-ideal back EMFs. ...
... Reference [15] compares the performance of BLDC drives under DTC and PWM current control. Implementation details, including torque estimation and inverter voltage space vector representation, are covered in [16] and [17], demonstrating that DTC reduces torque ripple and improves dynamic response compared to conventional control. An enhanced DTC implementation for BLDC drives, using a hybrid two-and three-phase switching mode during commutation, is presented in [17,18]. ...
This article presents a direct torque control (DTC) scheme with an integrated switching strategy to reduce commutation torque ripple in a dual inverter-fed three-phase BLDC motor with open-end stator windings. The proposed scheme covers both low- and high-speed operation, utilizing voltage space vector structures in two-phase and three-phase conduction modes. Analysis shows that utilizing three-phase conducting voltage vectors during the commutation interval significantly reduces torque ripple compared to the DTC scheme using only two-phase conducting voltage space vectors. The two-phase conducting voltage vectors however maximize electromagnetic torque during the non-commutation period. The proposed scheme results in unipolar switching that minimizes dv/dt leading to further reduction in torque ripple. Experimental validation on a laboratory prototype using a TMS320F28377S controller confirms the effectiveness of the proposed method.
... The key factors influencing torque ripple in BLDCMs encompass a wide range of design and control aspects, including modulation strategies, motor design considerations, eccentricities, control techniques, and voltage/current control strategies (Mohanraj, Gopalakrishnan, et al., 2022), (Liu et al., 2005), (Shi et al., 2017). The stator slot shape, stator slot opening width, winding pattern, commutation strategy, rotor design, stator and rotor skewing all play crucial roles in influencing torque ripple in BLDCMs (Prabhu et al., 2023), (Huang et al., 2012), (Rahman et al., 2014). ...
Brushless direct current motors (BLDCM) have been frequently preferred in the industry, especially in home appliances, due to their advantages such as long life, high efficiency, low maintenance costs and ease of control. In addition to these advantages, the main disadvantages of these motors are known to be high torque ripple and vibration levels. In this study, alternative asymmetric designs are realized in the stator tooth structure of the BLDCM designed for home appliances, and comparative analyses of the effects of the non-uniform air gap caused by the asymmetric tooth structure on the motor performance are presented. Two different asymmetric structures, namely the model with clockwise asymmetric design (CW) and the model with counterclockwise asymmetric design (CCW) in the stator tooth structure, are determined in the stator design. With these alternative designs, improvements are made in terms of torque ripple and cogging torque when compared with the reference motor; notably, the CCW-2 model achieves the lowest ripple at 19.4% compared to 23.1% for the reference motor, and a 42% reduction in cogging torque. The design of the motor models is made in ANSYS EDT program as two dimensional (2D) and analyzed with the Finite Element Method (FEM). In the analysis results, air gap flux density, torque, torque ripple and cogging torque are examined, and the flux density and torque spectrum obtained by Fast Fourier Transform (FFT) are presented comparatively
... One of these methods, as mentioned in [4], involves the utilization of a hysteresis current controller (HCC); however, it still faces challenges associated with high torque ripple. Some other approaches include the utilization of direct torque control methods, which are elaborated in [5][6][7][8][9][10][11][12] and have shown enhanced performance especially when combined with a hysteresis control strategy. Nevertheless, these methods are also vulnerable to experiencing high torque ripple and variable switching frequencies. ...
This paper focuses on the selection of the most suitable values for the PI controller parameters to minimize the discrepancy between the desired reference values and the actual values of speed and torque in the context of Space Vector Pulse Width Modulation-Direct Torque Control (SVPWM-DTC) of Brushless DC motors (BLDCM). To effectively fine-tune the PI controller, the criteria of Integral of Squared Speed Error (ISSE), Integral of Squared Torque Error (ISTE), and Integral of Squared Flux Error (ISFE) are taken into account as the objective functions across various scenarios. Nevertheless, when it comes to optimizing multiple objective functions, the most optimal approach is to reduce their linear combination. This paper employs JAYA and Sine Cosine algorithms (SCA) for the calibration of the gain parameters of the PI Controller. To assess the effectiveness of the proposed optimal PI controller for SVPWM-DTC of BLDCM, simulations are conducted. According to the findings of the simulations, the Sine Cosine technique yields a remarkable improvement by reducing the torque ripple and controlling the speed peaks overshoot reducing it to 61.6% and 11.9% respectively, and the JAYA algorithm.
... To eliminate electromagnetic torque pulsations and achieve more precise torque control of the electric motor (EM), it is necessary to control the flux linkage and the magnitude of the current flowing through the stator winding. The problem of direct torque control in a BLDC motor can be addressed in three ways: through direct flux linkage control, indirect flux linkage control, or without flux linkage control [1][2][3]. When flux linkage control is absent from the ECU, to eliminate electromagnetic torque pulsations between commutations, the magnetic system of the electric motor must be designed such that the current flowing through the winding between commutations is subject to a constant magnetic field. ...
... Revisiting Fig. 5, it can be seen that the change in the motor output torque is evident when trying to achieve a smooth closing curve. By using a straightforward method such as adjusting the duty cycle of the IGBT drive signal, we can take advantage of the solid dynamic properties of the motor to dynamically adjust its output torque and produce a better motion process [23]. In this study, the closing process is divided into four angle intervals: 0 • -23 • , 23 • -34 • , 34 • -52 • and 52 • -64 • , as shown in Figs. 4 and 5, and have been named as the start-up stage, the measurement stage, the overtravel stage, and the buffer stage. ...
This study has designed a set of motor operating devices for a 126 kV vacuum circuit breaker (VCB) to improve its reliability and controllability. A finite‐angle permanent magnet brushless motor (FAPMBM) with a multi‐slot stator structure and a dovetail rotor structure has been designed based on the torque and speed requirements of the motor. These requirements were determined by a dynamic analysis of the operating device and its short‐time, finite‐angle working characteristics. The work performance of the prototype motor has been evaluated in an online experiment with a 126 kV VCB, and based on this, a segmented control method has been designed. The motion process of the operating device has been divided into four stages in combination with the output torque demand of the driving motor. At each stage, the output torque of the motor has been changed dynamically to prevent contact collision, shorten the pre‐breakdown time, and make the circuit breaker work more reliably. The results show that the FAPMBM can meet the operating time and speed requirements of the interrupter for the operating device. In addition, the segmented control method improves the work reliability and optimizes the movement of the operating device, which helps the circuit breaker work intelligently. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.
... Based on torque estimation and inverter voltage space vector, a novel BLDCM Direct Torque Control (DTC) was proposed to control the instantaneous torque and reduce the torque ripple [5]. The Field-Oriented Control (FOC) scheme for BLDCM driven by voltage source inverter (VSI) is realized by using sinusoidal and space vector pulse width modulation to control the motor parameters on d-q axis [6]. ...
... To make it clear, the output torque T e can be divided into three constituent components: PM torque T PM , reluctance torque T r , and cogging torque T cog . These can be expressed as [28,29]: ...
The influences of slot/pole number combinations on electromagnetic performances, including flux linkage, inductance, and torque ripple harmonic components etc., resulting from unbalanced characteristics between north and south poles in concentrated winding permanent magnet (PM) machines with symmetrical and asymmetric rotor pole shaping methods are theoretically analysed and experimentally validated in this paper. It shows that for the PM machines with odd number of coils per phase per submachine, including consequent pole (CP) and surface‐mounted PM (SPM) machines, the influences of unbalanced pole characteristics can lead to additional torque ripple harmonics due to additive effects in windings, but can be cancelled in other machines. Compared with symmetrical pole shaping method, asymmetric pole shaping method can result in lower torque ripple for CPPM machines with odd number of coils per phase per submachine, while symmetrical and asymmetric pole shapes have similar effects on torque ripple reduction for other CPPM machines and all the SPM machines. The findings have been validated by finite element analyses on 12‐slot/8‐pole, 12‐slot/10‐pole, 9‐slot/6‐pole, and 12‐slot/14‐pole machines, and by experiments with 12‐slot/8‐pole and 12‐slot/10‐pole CPPM prototypes.
... Due to these advantages, authors in [11,12] tried the FOC principle to find the optimal current excitation component as an extension over the main controller. Another widely accepted control technique for the AC motors is the DTC [13,14]. It has been primarily proposed for IMs and has been then utilized in BLDC motor control [15,16]. ...
In this paper, the Nonlinear Model Predictive Control (NMPC) technique is proposed for the control of BrushLess Direct Current (BLDC) motors to address the problem of over-excitation, specifically in Electric Vehicle (EV) applications. This over-excitation increases the overall energy consumption of the machine and eventually reduces the vehicle’s driving range. The developed NMPC incorporates a nonlinear model of the BLDC motor with EV load and obtains the optimal current through the optimal voltage applied to the machine to regulate the motor torque. The proposed NMPC is compared with three conventional control techniques, the Field-Oriented Control (FOC), the Direct Torque Control (DTC), and the hybrid (the combination of DTC and FOC) control. It is observed from the simulation results that the proposed NMPC controller is more energy efficient while maintaining performance. This paper also discusses the selection of the motor based on the specified vehicle requirements. This has been done by matching the vehicle speed-torque characteristic curve with the motor’s one.
... Zhu defined zero-voltage vector as all inverter switches were off [24]. But in a two-phase conduction BLDCM, the effect of the all-turn-off voltage vector was equivalent to the inverse vector, which will cause a larger torque drop [25]. ...
BLDCMs are widely used in automotive, industrial and intelligent equipment fields due to their high power density, simple control, and good dynamic performance. However, its non‐sinusoidal characteristics have brought problems such as turn‐off phase freewheeling to the research and application of BLDCM DTC. This paper proposes the definition, particular characteristic analysis, selection scheme and realization method of the voltage vector, especially the novel zero‐voltage vector. Based on the novel zero‐voltage and twelve‐sector vector selection switch table, an improved PWM modulation strategy in a single cycle is proposed to cooperate with them to achieve the reduction of torque ripple. Finally, the correctness and feasibility of the proposed voltage vector and control strategy theory are verified by a series of experiments.
... There are several methods to vary the speed of the BLDC motor over a wide range. The most modern technique is direct torque control method (DTC) [1].The DTC offers many advantages like fast torque response, no need of coordinate transformation and less dependence on the rotor parameters. The conventional PI, PID control methods are widely used in motor control system due to the simple control structure and easiness of design. ...
... Another solution is to place permanent magnets on the rotor of the machine [13,14]. This solution eliminates the mechanical commutator, which causes frequent failures of DC machines [15,16]. Electric machines with permanent magnets placed on the rotor are divided into two types: ...
BrushLess Direct-Current (BLDC) motors are characterized by high efficiency and reliability due to the fact that the BLDC motor does not require power to the rotor. The rotor of the BLDC motor consists of permanent magnets. When examining the waveform of the current supplied to the motor windings, significant current ripple was observed within one power cycle, where the optimum value would be the constant value of this current during one power cycle. The variability of this current in one motor supply cycle results from the variability of the electromotive force induced in the motor winding. The paper presents a diagram of the power supply system consisting of an electronic commutator and a DC/DC converter made by the authors, and a proposed modification of the power supply system reducing the current pulsation of the motor windings and thus the possibility of reducing energy losses in the motor windings. The paper presents numerous results of measurements which showed a significant reduction in energy losses in the case of low-load operation.
... The aim is to use a suitable switching state to reach the desired torque value [16][17][18]. Similar to induction and synchronous machines, direct torque control (DTC) has been implemented for BLDC machines [19][20][21][22][23][24][25][26][27][28][29]. DTC dominates the torque and flux directly by using 2 hysteresis controllers. ...
Brushless DC motors (BLDCs) are highly efficient and have the least maintenance requirement due to which they have replaced many conventional AC motors in various applications like electric vehicles, fans, water pumps, and home appliances. However, like all conventional motors, performance degradation of the BLDC motors can occur due to faults like Hall sensors failure, commutation switch failure, and stator‐winding failure. Among all these failures, this paper focuses on Hall sensor failures and the execution of fault tolerant control. Hall sensors produce an output after every 60° of rotation of the rotor, generating six sequences in one electrical cycle. In this study, each sequence is defined as a sector, which corresponds to the rotor position. Based only on this sector information in each electrical cycle, this paper proposes an uncomplicated detection strategy for Hall sensor fault, which is independent of motor loading and high‐performance processing unit. Along with the diagnosis, an improved faulty signal reconstruction is implemented, which bypasses the fault and continues a smooth performance of the motor. The proposed detection and reconstruction strategies have been simulated in MATLAB Simulink 2020, and the experimental analysis has been conducted to validate the proposed strategies.
Recent technological advancements have propelled remarkable progress in servo systems, resulting in their extensive utilization across various high-end applications. A comprehensive review of high-quality servo system technologies, focusing specifically on electrical motor topologies and control strategies is presented. In terms of motor topology, this study outlines the mainstream servo motors used across different periods, as well as the latest theories and technologies surrounding contemporary servo motors. In terms of control strategies, two well-established approaches are presented: field-oriented control and direct torque control. Additionally, it discusses advanced control strategies employed in servo systems, such as model predictive control (MPC) and fault tolerance control, among others.
In recent years, electric vehicles (EVs) have attracted a lot of attention and are rapidly growing trends today due to their ability to compete with and overtake fossil fuel-powered vehicles among all electrified transportation tools. The primary focus of EV evolution is on improving driving range and optimizing energy consumption, both of which are essential demands achieved through improved and developing motor performance. The brushless direct current (BLDC) motor is one of the most superior choices for dynamic applications in EVs, providing the highest power density and capability of any motor. BLDCs are gaining popularity in EVs not only for their high performance in speed and position controls but also for meeting the requirements of smooth torque maintenance with torque ripple mitigation. This paper provides an overview of various advanced control strategies, such as field-oriented control (FOC), direct torque control (DTC), intelligent control (IC), controlling input voltage (CIV), current shaping techniques (CST), model predictive control (MPC), and sliding mode control (SMC). These strategies are used to regulate the torque ripples produced in BLDC motors, aiming to achieve energy-efficient EV performance for various applications. Additionally, it describes a cloud-based control system coupled with electric motor drives to address challenges in predicting current vehicle conditions for improved power distribution between the motor and battery systems. Furthermore, recent concerns and difficulties in advancing torque ripple mitigation control strategies are highlighted, with comparisons and discussions for future EV research. Finally, an evaluative study on BLDC motor drive in EVs with different control strategies reveals its significance and potential outcomes.
In the electric three-wheeler vehicular segment, permanent magnet (PM) motors are strong competitors for traction applications. The vehicular environment faces sudden load variations, where traditional control like field-oriented control (FOC) over-excites the machine. It also degrades the machine’s overall performance due to dynamic changes in the motor states with limited bandwidth of the cascaded proportional-integral (PI) controllers; this makes the overall motor operation inefficient. The paper proposes a model predictive control (MPC) based on torque ripple and over-current excitation minimization for permanent magnet motors to overcome these challenges. The proposed controller is tailored to improve the overall electrical efficiency of permanent magnet motors while considering the real back EMF. The performance of the proposed controller is tested in simulation, considering an electric three-wheeler as a load along with a European driving cycle. The feasibility of the proposed method is tested by deployment on (1) STM32F546ZG micro-controller and (2) Xilinx’s ZYNQ-7000 SoC ZC706 FPGA and validated the implementation results with hardware-in-the-loop(HIL) co-simulation. The implementation results show that the proposed MPC outperforms the conventionally used FOC in energy consumption, torque ripples minimization, and torque disturbance handling while tracking the desired speed accurately with load variations.
This book gathers selected high-impact articles from the 3rd International Conference on Data Science, Machine Learning & Applications 2021. It highlights the latest developments in the areas of artificial intelligence, machine learning, soft computing, human–computer interaction and various data science and machine learning applications. It brings together scientists and researchers from different universities and industries around the world to showcase a broad range of perspectives, practices and technical expertise.
This paper gives a concise review on mathematical modeling of brushless direct current (BLDC) motor, the challenges on BLDC motor, torque ripple reduction techniques, condition for minimum commutation torque ripple, and different control strategies for torque ripple reduction in sensor and sensorless BLDC motor. This review also discusses the comparison between sensor and sensorless BLDC drives, merits of sensorless BLDC drive, and outcomes of different torque ripple reduction techniques. It also gives an idea to select better control strategy for specific BLDC drive applications. The best-suited control strategies have the advantages such as high efficiency, minimum torque ripple over the entire speed range, less switching loss, simple modulation scheme, improvement in DC voltage utilization, smooth and noiseless operation, and regulation in the speed of BLDC motor. The MATLAB simulation tool is used to verify the results of few topologies.
In this paper a modified BLDC motor having a wide flat topped back emf waveform of around 169
is designed and presented. This motor when excited with an appropriate current waveform as proposed in this paper provides around 13.8% improvement in torque density while ensuring that the torque ripple to remain same as that of a conventional BLDC motor drive. Further, the proposed drive can be realized by employing only three hall sensors, and the control configuration remains to be simple as that of a conventional BLDC motor drive involving two phase conduction. The proposed motor of 3.6 kW rating has been designed, and its various design parameters are verified on an FEM based platform, MAGNET. A 3.6 kW motor has been fabricated and a conventional three leg inverter is employed to drive the motor. The controller for the drive has been realized by utilizing a TMS320F28335 dsp board. The efficacy of the proposed drive is verified by performing detailed simulation and experimental studies.
In this paper, a simulation study enhanced to model that the speed control of brushless direct current (BLDC) motors used in electric vehicles with intelligent control methods. The simulation study was prepared in Matlab/Simulink environment. The first control method is Type-1 fuzzy logic control (T1FLC), and the second control method is the Intermittent Type-2 fuzzy logic control (IT2FLC) model. Membership functions for different membership numbers have been created for both types of FLC models. These are 3×3, 5×5, 7×7. Control methods are prepared in Matlab/M-file environment. The model is defined as the input variable of the error, which is the difference between the reference speed and the motor speed, and the output variable of the Pulse Width Modulation (PWM) signal applied to the motor. The simulation study maintains the speed of the BLDC motor up to the reference speed with T1FLC and IT2FLC controllers, depending on the reference speed and applied load values. Depending on the number of different memberships, the effects of controller performances on the control of motor speed have been observed. The graphs and findings of the experiment are shown in the results and discussion section.
Consequent-pole (CP) permanent magnet (PM) machines have attracted considerable interest as a means of reducing machine cost through a marked reduction in the volume of PM required to meet a particular torque specification. However, the presence of a large torque ripple that can result from the CPPM structure can hinder their adoption in some applications, especially for the dominant third-order torque ripple. Although several design-specific modifications have been proposed to ameliorate torque ripple, the generalized principles underpinning this behavior have not been fully established. In this article, it will be illustrated that an aggregation of the fluctuations in inductance, back electromotive force, and cogging torque contributes to increased torque ripple. Meanwhile, an asymmetric pole shaping method is proposed to reduce the torque ripple, taking the dominant third-order torque ripple as an example. Both simulated and experimental results of the 12-slot/8-pole prototypes show that compared to the symmetrical pole shaping model and the plain pole model, the proposed asymmetric shaping method is effective in reducing torque ripple.
Consequent pole (CP) permanent magnet (PM) machines offer scope for reducing the quantity of PM material and hence cost compared to more conventional PM machine topologies of the same rating. In this type of machine, the rotor pole arc is usually optimized to realize the largest output torque with pole shaping methods used to reduce torque ripple. However, such approaches tend to be limited by constraints imposed on the pole shapes. It is a common practice to adopt similar PM and iron pole shapes, an approach that does not fully account for the different characteristics of PM and iron poles in CPPM machines, often leading to large even order harmonics in the airgap flux density. This article proposes a shaping method with a variable rotor profile and pole arc span being established by means of optimization by Genetic Algorithm. It is demonstrated that for a fixed quantity of PM material, different PM and iron pole shapes in combination with optimal PM and iron pole arc spans are essential for ensuring both maximum output torque and lower torque ripple when the due account is taken of flux leakage. It also demonstrates that since the flux density in the region under a PM pole is governed by the magnetic potential produced by magnets while it is governed by magnetic reluctance under iron pole, different PM pole and iron pole shapes are necessary to reduce the even-order harmonics in a CPPM machine and consequently to reduce torque ripple. The performances of optimized and more conventional CP machines are compared by finite-element method on 12-slot/8-pole prototype motors.
Efficient, safe, and comfortable electric vehicles (EVs) are essential for the creation of a sustainable transport system. Distributed-driven EVs, which often use in-wheel motors (IWMs), have many benefits with respect to size (compactness), controllability, and efficiency. However, the vibration of IWMs is a particularly important factor for both passengers and drivers, and it is, therefore, crucial for the successful commercialization of distributed-driven EVs. This article provides a comprehensive literature review and state-of-the-art vibration-source analysis and mitigation methods in IWMs. First, selection criteria are given for IWMs, and a multidimensional comparison for several motor types is provided. The IWM vibration sources are then divided into internally and externally induced vibration sources and discussed in detail. Next, vibration reduction methods, which include motor-structure optimization, motor controller, and additional control components, are reviewed. Emerging research trends and an outlook for future improvement aims are summarized at the end of this article. This article can provide useful information for researchers who are interested in the application and vibration mitigation of IWMs or similar topics.
This paper presents a micro‐hydro generator driven frequency adaptive sliding mode (FASM) control‐based improved power quality permanent magnet brushless DC motor (PMBLDCM) driven air conditioning system for remote and hilly areas. In such locations, the grid availability is poor or limited. The self‐excited asynchronous generator (SEAG) is highly suitable for micro‐hydro power generation. The voltage and frequency regulations of SEAG systems are very poor. Therefore, an improved power quality FASM control of a new zeta function based modified CSC (ZFM‐CSC) converter scheme is developed to drive the micro‐hydro power driven SEAG fed air conditioning system. The conventional air‐conditioning schemes are suitable for the grid fed system, where the frequency and voltage remain constant. However, these conventional control schemes are not suitable for a standalone SEAG based micro‐hydro generator driven air conditioners since the frequency and voltage of this system vary frequently at different loadings and dynamic operating conditions. This leads to an incorrect estimation of reference source current in a conventional system, which in turn affects the system stability. The sudden change of loads in a conventional air conditioning system may de‐magnetize and de‐stabilize the micro‐hydro driven SEAG. The experimental and simulated results presented validate the robustness of this system.
The solar energy is clean and future energy for electricity generation. Its energy has enormous potential but do not optimal to utilized caused by intermittent energy. The intermittent radiance and ambient temperature influence the energy produced fluctuates and unstable. These power fluctuations affect system stability and frequency. To overcome this problem, several methods for PV power stabilization have been developed. One of them is the Stabilized Power Generation where PV output power is to a certain power value. The result of SPG method is reducing in PV power fluctuations but still unstable.
The use of DC motors in the industry due to outstanding specifications such as extensive control of high efficiency and speed. .. It is very common, the only drawback of this type of engine is the need for commutators and brooms because these components are constantly eroding and therefore increase the need for service and maintenance of the engine.
Robust dynamic speed response with less maintenance and efficient operation makes the Brushless Direct Current (BLDC) motors as an oblivious choice for many motoring applications which needs instantaneous speed control while developing high torque. This paper proposes Jaya optimization Algorithm on Xilinx platform for BLDC Motor and Fractional Order Proportional Integral Derivative controller to improve its efficiency through minimizing the ripples present in the Torque of the motor. The control strategy of torque controller works with the combinations of Xilinx and optimization algorithms. In this proposed controller, the strategy of control is achieved after deriving the BLDC motor's dynamic mode there after the electronic interaction with BLDC motor is enrooted with the Math lab/Simulink model while tactically utilizing Xilinx tools for all kind of co-simulation in the same model. Initially the dynamic model of a BLDC motor drive is derived and the control topology is designed with the help of the proposed controller. The controlling mechanism established in this paper is effective and efficient in minimizing the ripples present in the torque of the motor. The proposed controller is utilized for possible low-cost and high-performance industrial applications. The results are obtained and analyzed with existing methodologies and it shows that the proposed technique outperforms the existing models.
The Direct Torque Control on Space Vector Modulator of Induction motor is modeled to reduce the torque ripples. The conventional approaches are used various controlling strategies for determining the performance of motor drive system. Here the controlling section mainly utilized with switching activity of the device. Here the proposed model is designed to rectify the problem of overcoming the modulation at high speed Induction motor. In proposed DTC of Induction Motor, designed with discrete switching activity by generating the gated pulse from PWM and it is modeled based on the Space Vector Modulator. The discrete switching activity is performed with referring peak voltage and offset voltage with initial state of zero. By adding these voltages, the vector voltage is generated to occupy the SVM - Induction machine; therefore, this reduces the torque ripples and harmonic signals. Here the adaptive pulse width modulator generates the pulse by controlling the torque and flux ripples using PI controller. The experimental result shows the 4.3% reduction of torque ripples and 0.7% reduction of flux ripples. This makes the discrete clock switching for performing the Induction motor. The closed loop flux controlling strategy is enabled to perform best result of rated speed, torque and stator flux. By analyzing various conventional methods, the proposed model utilized to obtain better result. The overall design is done with the help of MATLAB/2018a tool.
This paper presents a comparative study of three-phase permanent-magnet brushless machines in which the slot and pole numbers are similar, with reference to conventional brushless dc machines in which the ratio of the slot number to pole number is usually 3 : 2. Three different motor designs are considered. Two have equal tooth widths, with one having a coil wound on every tooth and the other only having a coil wound on alternate teeth, while the third machine also has coils wound on alternate teeth but these are wider than the unwound teeth while the width of their tooth tips is almost equal to the rotor pole pitch in order to maximize the flux linkage and torque. Analytical and finite-element methods are employed to predict the flux-linkage and back-electromotive-force waveforms, and the self- and mutual-inductances, and these are shown to be in good agreement with measured results. It is also shown that the third machine is eminently appropriate for brushless dc operation.
Among various types of motor drives, permanent magnet (PM) brushless motor drives, especially the PM synchronous motor drive, are currently the most attractive motor drives for electric vehicle (EV) propulsion. This chapter presents two major PM brushless motor drives, namely the PM synchronous and PM brushless DC (BLDC) types. It describes their PM materials, system configurations, machine topologies, inverter topologies, and control strategies. The chapter also discusses the corresponding design criteria, design examples, and application examples for EV propulsion. PM materials are the key of PM brushless motor drives that provide the machines with lifelong excitation. The system configuration of PM brushless motor drives for electric propulsion is similar to that of induction motor drives. PM brushless motors have become the preferred choice for EV propulsion because of their high efficiency and high power density.
New quick-response and high-efficiency control of an induction motor, which is quite different from that of the field-oriented control is proposed. The most obvious differences between the two are as follows. 1) The proposed scheme is based on limit cycle control of both flux and torque using optimum PWM output voltage; a switching table is employed for selecting the optimum inverter output voltage vectors so as to attain as fast a torque response, as low an inverter switching frequency, and as low harmonic losses as possible. 2) The efficiency optimization in the steady-state operation is also considered; it can be achieved by controlling the amplitude of the flux in accordance with the torque command. To verify the feasibility of this scheme, experimentation, simulation, and comparison with field-oriented control are carried out. The results prove the excellent characteristics for torque response and efficiency, which confirm the validity of this control scheme.
This paper presents the fundamentals of a new class of torque speed and position controllers for electric drives, characterized by the association of a modified sliding mode position (speed) controller and stator flux control through a unique table of optimal conduction sequence to fire directly the static power converter SCR switches. Robustness is provided by the sliding mode controller and stator (instead of rotor) flux vector estimation while control precision is secured by the torque pulsation controller. Fast response is obtained through the table of optimal conduction sequence which leads to the fastest response available through a stator flux vector (or stator accelerating field) control obtained without the transformation of coordinates or special techniques. The control computation time (costs) is drastically reduced in comparison with PWM transvector (or field accelerating) methods while the performance in terms of precision, response and robustness are better.
An AC brushless drive in which Hall effect sensors are used as rotor position sensors is presented in this paper. Three different methods to obtain high resolution position information from the low resolution sensors are described and compared through simulation and some preliminary experimental testing. The proposed control algorithm's most innovative feature is it's adaptability to the whole speed range, including start-up, when using any of the three estimation algorithms. The entire control algorithm has been implemented and tested in order to drive an axial-flux PM machine for home appliance applications.
A new instantaneous torque control strategy is presented for the
high performance control of a permanent magnet synchronous motor. In
order to deal with the torque pulsation problem of the PM synchronous
motor in the low-speed region, new torque estimation and control
techniques are proposed. The linkage flux of the PM synchronous motor is
estimated using a model reference adaptive control system technique and
the developed torque of the motor is instantaneously controlled by a
torque controller combining variable structure control with space vector
PWM. The proposed control scheme provides the advantage of reducing the
torque pulsation caused by the nonsinusoidal flux distribution of the
motor. This control strategy is applied to a high torque PM synchronous
motor drive system for direct drive applications and implemented by
using a software of the DSP TMS320C30. Computer simulations and
experiments are carried out for this system and the results demonstrate
well the effectiveness of the proposed control strategy
Permanent-magnet brushless DC drives can have excellent
performance in direct-drive servo applications provided suitable control
techniques are implemented. This calls for a cascade control strategy in
which the controller is divided into two control loops: an outer loop
which generates the instantaneous torque reference signal required to
track acceleration, velocity or position; and an inner loop which forces
the developed instantaneous torque to follow the torque command. In most
conventional control algorithms, the inner loop is designed to produce
sinusoidal stator currents, thus giving rise to significant torque
ripples if the motor has a back EMF waveform which differs appreciably
from the ideal sinusoid. A digital torque control scheme is proposed
which uses the variable structure approach to generate the on-off
switching patterns (vectors) directly with a microprocessor. At every
switching instant, the optimum vector is selected to force the developed
torque to follow the torque reference while keeping the direct axis
current as close to zero as possible for the highest efficiency. The
instantaneous torque feedback signal can be estimated from the terminal
quantities of the motor. Simulation results are presented
Brushless DC (BLDC) drives with permanent-magnet motors are suitable as servo-motors if properly controlled. Their performance can be superior to that of conventional DC servos if NdFeB or rare-earth cobalt magnets are used for motor excitation and novel control techniques are implemented for its servo performance. The availability of inexpensive but high-performance digital signal processors allows the implementation of a novel instantaneous torque control algorithm for the BLDC drive applications. Described are the servo performances of a BLDC drive with instantaneous torque control. To assess the quality of this controller, its performance is compared with those obtained using conventional current controllers. Details of the control strategies are also described.< >
The paper describes an instantaneous torque control for a
permanent magnet motor driven in a brushless direct current drive
configuration. The motor has high torque capabilities, which makes it
suitable for direct drive applications, but unfortunately it suffers
from torque pulsations when controlled by a conventional sinusoidal
current controller. Instantaneous torque control is aimed at eliminating
such torque pulsation, thereby improving speed and position control. The
approach adopted is to design an instantaneous torque control algorithm
based on a variable structure strategy in the dq rotating
reference frame. The switching commands for the inverter are generated
by the digital controller directly. The required instantaneous torque
feedback information is estimated from knowledge of the motor parameters
and measurements of instantaneous currents and rotor position. The
performance of the proposed controller design and torque feedback
technique are investigated in computer simulation studies and
experimental implementations. Experimental results for drive
applications using instantaneous torque control and conventional
sinusoidal current control are evaluated and compared
A new instantaneous torque-control strategy is presented for
high-performance control of a permanent magnet (PM) synchronous motor.
In order to deal with the torque pulsating problem of a PM synchronous
motor in a low-speed region, new torque estimation and control
techniques are proposed. The linkage flux of a PM synchronous motor is
estimated using a model reference adaptive system technique, and the
developed torque is instantaneously controlled by the proposed torque
controller combining a variable structure control (VSC) with a
space-vector pulse-width modulation (PWM). The proposed control provides
the advantage of reducing the torque pulsation caused by the
nonsinusoidal flux distribution. This control strategy is applied to the
high-torque PM synchronous motor drive system for direct-drive
applications and implemented by using a software of the digital signal
processor (DSP) TMS320C30. The simulations and experiments are carried
out for this system, and the results demonstrate the effectiveness of
the proposed control
This paper describes an investigation of direct torque control
(DTC) for permanent magnet synchronous motor (PMSM) drives. It is
mathematically proven that the increase of electromagnetic torque in a
permanent magnet motor is proportional to the increase of the angle
between the stator and rotor flux linkages, and, therefore, the fast
torque response can be obtained by adjusting the rotating speed of the
stator flux linkage as fast as possible. It is also shown that the zero
voltage vectors should not be used, and stator flux linkage should be
kept moving with respect to the rotor flux linkage all the time. The
implementation of DTC in the permanent magnet motor is discussed, and it
is found that for DTC using available digital signal processors (DSPs),
it is advantageous to have a motor with a high ratio of the rated stator
flux linkage to stator voltage. The simulation results verify the
proposed control and also show that the torque response under DTC is
much faster than the one under current control
In this paper a method of the torque control attenuating the
undesired torque pulsation for brushless DC motor with nonideal
trapezoidal back EMF is presented. It is the direct torque control
method in which the applied output voltage is calculated from the
reference torque and the torque of the previous step in the two-phase
conducting period and in the commutation period considering the back EMF
waveform. The time delay due to the calculation is compensated by the
one step ahead current prediction. To measure the instantaneous torque
ripple, a torque observer is constructed using a high precision encoder
of 50000 pulse per revolution. The simulation and experimental results
show that the proposed method reduces the torque ripple significantly
and that it keeps the torque control dynamics as well
The new direct self-control (DSC) is a simple method of signal
processing that gives converter-fed three-phase machines an excellent
dynamic performance. To control the torque of, say, an induction motor,
it is sufficient to process the measured signals of the stator currents
and the total flux linkages only. In the basic version of DSC, the power
semiconductors of a three-phase voltage source inverter are directly
switched on and off via three Schmitt triggers, comparing the time
integrals of line-to-line voltages to a reference value of desired flux,
if the torque has not yet reached an upper-limit value of a two-limit
torque control. Optimal performance of drive systems is accomplished in
steady state as well as under transient conditions by combination of
several two-limit controls
Torque-ripple control of the brushless DC motor has been the main
issue of the servo drive systems in which the speed fluctuation,
vibration, and acoustic noise should be minimized. Most methods for
suppressing the torque ripples require Fourier series analysis and
either iterative or least-mean-square minimization. In this paper, a
novel approach to achieve ripple-free torque control with maximum
efficiency based on the d-q-0 reference frame is presented. The proposed
method optimizes the reference phase current waveforms which include the
case of three-phase unbalanced conditions. As a result, the proposed
approach provides a simple way to obtain optimal motor excitation
currents. The validity and practical applications of the proposed
control scheme are verified through the simulations and experimental
results
Many permanent magnet motor drives use an open loop form of torque
control, based on the assumption that output torque is proportional to
applied current. In a practical motor this assumption may not always be
correct, due to suboptimal alignment of magnets, nonuniformity of
magnetic material, current sensor nonlinearities, and current controller
limitations. These factors, together with nonoptimized current
references, can lead to undesirable levels of torque ripple and copper
loss. This paper describes a method of estimating the electromagnetic
torque from the rate of change of coenergy with respect to position,
thus taking account of mutual torque, reluctance torque and saturation
effects. The paper shows how the estimator can be used in a direct
torque control scheme. The direct torque controller maximizes the
torque:copper loss ratio. Implementation of the direct torque controller
in a digital signal processor (DSP)-based drive system is described,
with steady-state and transient experimental results illustrating the
effectiveness of the direct torque control scheme
Brushless DC (BLDC) drives with permanent-magnet motors are
suitable as servo motors if properly controlled. Their performance can
be superior to conventional DC servos if NdFeB or rare-earth cobalt
magnets are used for motor excitation, and novel control techniques
implemented for its servo performance. The availability of inexpensive
and high-performance digital signal processors allows the implementation
of a novel instantaneous torque control algorithm for BLDC drive
applications. The authors present the servo performances of a BLDC drive
with instantaneous torque control. To assess the quality of this
controller, its performance is compared with that obtained using
conventional current controllers. Details of the control strategies are
also described
A new quick-response and high-efficiency control strategies of an induction motorAnalysis of direct torque control in permanent magnet synchronous motor drives
- I Takahashi
- T Noguchi
- L Zhong
- M F Rahman
- W Y Hu
- K W Lim
I. Takahashi and T. Noguchi, "A new quick-response and high-efficiency control strategies of an induction motor," IEEE Trans. Ind. Appl., vol. 22, no. 5, pp. 820–827, Sep./Oct. 1986. [12] L. Zhong, M. F. Rahman, W. Y. Hu, and K. W. Lim, "Analysis of direct torque control in permanent magnet synchronous motor drives," IEEE Trans. Power Electron., vol. 12, no. 3, pp. 528–536, May 1997.
Anewquick-responseandhigh-efficiency controlstrategiesofaninductionmotor
- I Takahashiandt
- Noguchi
I.TakahashiandT.Noguchi,“Anewquick-responseandhigh-efficiency controlstrategiesofaninductionmotor,”IEEETrans.Ind.Appl.,vol.22, no. 5, pp. 820–827, Sep./Oct. 1986. r608IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 41, NO. 2, MARCH/APRIL 2005